Agenda packet — Aliso Viejo City Council, December 3, 2025 (part 2 of 17)

5.3. Construction Vehicles

5.3.1. Unmitigated
Phase Name Trip Type One-Way Trips per Day Miles per Trip Vehicle Mix Demolition — — — —
Demolition Worker 12.5 18.5 LDA,LDT1,LDT2
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Demolition Vendor — 10.2 HHDT,MHDT
Demolition Hauling 81.3 20.0 HHDT
Demolition Onsite truck — — HHDT
Site Preparation — — — —
Site Preparation Worker 7.50 18.5 LDA,LDT1,LDT2
Site Preparation Vendor — 10.2 HHDT,MHDT
Site Preparation Hauling 0.00 20.0 HHDT
Site Preparation Onsite truck — — HHDT
Grading — — — —
Grading Worker 10.0 18.5 LDA,LDT1,LDT2
Grading Vendor — 10.2 HHDT,MHDT
Grading Hauling 50.0 20.0 HHDT
Grading Onsite truck — — HHDT
Building Construction — — — —
Building Construction Worker 43.9 18.5 LDA,LDT1,LDT2
Building Construction Vendor 6.52 10.2 HHDT,MHDT
Building Construction Hauling 0.00 20.0 HHDT
Building Construction Onsite truck — — HHDT
Paving — — — —
Paving Worker 15.0 18.5 LDA,LDT1,LDT2
Paving Vendor — 10.2 HHDT,MHDT
Paving Hauling 9.00 20.0 HHDT
Paving Onsite truck — — HHDT
Architectural Coating — — — —
Architectural Coating Worker 8.78 18.5 LDA,LDT1,LDT2
Architectural Coating Vendor — 10.2 HHDT,MHDT
Architectural Coating Hauling 0.00 20.0 HHDT
Architectural Coating Onsite truck — — HHDT
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5.4. Vehicles

5.4.1. Construction Vehicle Control Strategies
Non-applicable. No control strategies activated by user.

5.5. Architectural Coatings
Phase Name Residential Interior Area
Coated (sq ft)
Residential Exterior Area
Coated (sq ft)
Non-Residential Interior Area
Coated (sq ft)
Non-Residential Exterior Area
Coated (sq ft)
Parking Area Coated (sq ft)
Architectural Coating 307,047 102,349 0.00 0.00 2,378

5.6. Dust Mitigation

5.6.1. Construction Earthmoving Activities
Phase Name Material Imported (Cubic
Yards)
Material Exported (Cubic
Yards)
Acres Graded (acres) Material Demolished (Ton of
Debris)
Acres Paved (acres)
Demolition 0.00 0.00 0.00 6,500 —
Site Preparation 0.00 0.00 4.50 0.00 —
Grading 0.00 2,400 6.00 0.00 —
Paving 0.00 0.00 0.00 0.00 0.91

5.6.2. Construction Earthmoving Control Strategies
Control Strategies Applied Frequency (per day) PM10 Reduction PM2.5 Reduction Water Exposed Area 2 61% 61%
Water Demolished Area 2 36% 36%

5.7. Construction Paving
Land Use Area Paved (acres) % Asphalt
Condo/Townhouse — 0%
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Parking Lot 0.91 100%

5.8. Construction Electricity Consumption and Emissions Factors kWh per Year and Emission Factor (lb/MWh)
Year kWh per Year CO2 CH4 N2O
2026 370 346 0.03 < 0.005
2027 450 346 0.03 < 0.005

5.9. Operational Mobile Sources

5.9.1. Unmitigated
Land Use Type Trips/Weekday Trips/Saturday Trips/Sunday Trips/Year VMT/Weekday VMT/Saturday VMT/Sunday VMT/Year Condo/Townhouse 411 411 411 150,066 3,632 3,632 3,632 1,325,753 Parking Lot 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

5.10. Operational Area Sources

5.10.1. Hearths

5.10.1.1. Unmitigated
Hearth Type Unmitigated (number)
Condo/Townhouse —
Wood Fireplaces 0
Gas Fireplaces 0
Propane Fireplaces 0
Electric Fireplaces 0
No Fireplaces 61
Conventional Wood Stoves 0
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Catalytic Wood Stoves 0
Non-Catalytic Wood Stoves 0
Pellet Wood Stoves 0

5.10.2. Architectural Coatings
Residential Interior Area Coated (sq
ft)
Residential Exterior Area Coated (sq
ft)
Non-Residential Interior Area Coated
(sq ft)
Non-Residential Exterior Area
Coated (sq ft)
Parking Area Coated (sq ft)
307046.7 102,349 0.00 0.00 2,378

5.10.3. Landscape Equipment
Season Unit Value
Snow Days day/yr 0.00
Summer Days day/yr 250

5.11. Operational Energy Consumption

5.11.1. Unmitigated
Electricity (kWh/yr) and CO2 and CH4 and N2O and Natural Gas (kBTU/yr) Land Use Electricity (kWh/yr) CO2 CH4 N2O Natural Gas (kBTU/yr) Condo/Townhouse 444,090 346 0.0330 0.0040 0.00
Parking Lot 34,724 346 0.0330 0.0040 0.00

5.12. Operational Water and Wastewater Consumption

5.12.1. Unmitigated
Land Use Indoor Water (gal/year) Outdoor Water (gal/year) Condo/Townhouse 2,289,065 440,285
Parking Lot Appendix A 0.00 0.00 34 267
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5.13. Operational Waste Generation

5.13.1. Unmitigated
Land Use Waste (ton/year) Cogeneration (kWh/year)
Condo/Townhouse 45.2 —
Parking Lot 0.00 —

5.14. Operational Refrigeration and Air Conditioning Equipment

5.14.1. Unmitigated
Land Use Type Equipment Type Refrigerant GWP Quantity (kg) Operations Leak Rate Service Leak Rate Times Serviced Condo/Townhouse Average room A/C &
Other residential A/C
and heat pumps
R-410A 2,088 < 0.005 2.50 2.50 10.0
Condo/Townhouse Household
refrigerators and/or
freezers
R-134a 1,430 0.12 0.60 0.00 1.00

8. User Changes to Default Data
Screen Justification
Land Use Bldg Square footage is Gross for construction purposes and conservatively based on 3 story buildings at a site coverage 41 % (this estimate would include unconditioned built space such as garages, porches etc)
Landscaping from site plans
Parking represents interior roads and parking and calculated by subtracting building footprint/coverage and open space 33,092 sq ft
Construction: Construction Phases Building construction phases increased based on applicants schedule and density of the construction
Assume that on-site electricity is available for uses such as welding - air compressors and temporary power used in lieu of diesel generators
Construction: Off-Road Equipment Generator Reduced to 4 hours per day to reflect grid/temp power Appendix A Air Compressors and Welders - Electric 35 268 Argonaut Residential Custom Report, 1/31/2025
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Operations: Energy Use Calculational Method is from Measure E-15 of the CAPCOA Handbook for Analyzing Greenhouse Gas Emission Reductions, Assessing Climate Vulnerabilities, and Advancing Health
Construction: Trips and VMT Vendor Paving Trips for Asphalt Operations: Vehicle Data Trip Generation Rate = 6.74 Trips/DU for ITE Code 220 - to match Urban Crossroads Trip Generation (06.01.2024) and VMT Screening Evaluation Report (07.15.24)
Operations: Hearths No Wood stoves or Fireplaces
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Argonaut Residential - Localized Emissions Custom Report Table of Contents

1. Basic Project Information

1.1. Basic Project Information

1.2. Land Use Types

1.3. User-Selected Emission Reduction Measures by Emissions Sector

2. Emissions Summary

2.1. Construction Emissions Compared Against Thresholds

2.2. Construction Emissions by Year, Unmitigated

2.4. Operations Emissions Compared Against Thresholds

2.5. Operations Emissions by Sector, Unmitigated

3. Construction Emissions Details

3.1. Demolition (2026) - Unmitigated

3.3. Site Preparation (2026) - Unmitigated

3.5. Grading (2026) - Unmitigated

3.7. Building Construction (2026) - Unmitigated

3.9. Building Construction (2027) - Unmitigated
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3.11. Paving (2027) - Unmitigated

3.13. Architectural Coating (2027) - Unmitigated

4. Operations Emissions Details

4.1. Mobile Emissions by Land Use

4.1.1. Unmitigated

4.2. Energy

4.2.1. Electricity Emissions By Land Use - Unmitigated

4.2.3. Natural Gas Emissions By Land Use - Unmitigated

4.3. Area Emissions by Source

4.3.1. Unmitigated

4.4. Water Emissions by Land Use

4.4.1. Unmitigated

4.5. Waste Emissions by Land Use

4.5.1. Unmitigated

4.6. Refrigerant Emissions by Land Use

4.6.1. Unmitigated

4.7. Offroad Emissions By Equipment Type

4.7.1. Unmitigated
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4.8. Stationary Emissions By Equipment Type

4.8.1. Unmitigated

4.9. User Defined Emissions By Equipment Type

4.9.1. Unmitigated

4.10. Soil Carbon Accumulation By Vegetation Type

4.10.1. Soil Carbon Accumulation By Vegetation Type - Unmitigated

4.10.2. Above and Belowground Carbon Accumulation by Land Use Type - Unmitigated

4.10.3. Avoided and Sequestered Emissions by Species - Unmitigated

5. Activity Data

5.1. Construction Schedule

5.2. Off-Road Equipment

5.2.1. Unmitigated

5.3. Construction Vehicles

5.3.1. Unmitigated

5.4. Vehicles

5.4.1. Construction Vehicle Control Strategies

5.5. Architectural Coatings

5.6. Dust Mitigation
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5.6.1. Construction Earthmoving Activities

5.6.2. Construction Earthmoving Control Strategies

5.7. Construction Paving

5.8. Construction Electricity Consumption and Emissions Factors

5.9. Operational Mobile Sources

5.9.1. Unmitigated

5.10. Operational Area Sources

5.10.1. Hearths

5.10.1.1. Unmitigated

5.10.2. Architectural Coatings

5.10.3. Landscape Equipment

5.11. Operational Energy Consumption

5.11.1. Unmitigated

5.12. Operational Water and Wastewater Consumption

5.12.1. Unmitigated

5.13. Operational Waste Generation

5.13.1. Unmitigated

5.14. Operational Refrigeration and Air Conditioning Equipment Appendix A 40 273
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5.14.1. Unmitigated

8. User Changes to Default Data
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1. Basic Project Information

1.1. Basic Project Information
Data Field Value
Project Name Argonaut Residential - Localized Emissions Construction Start Date 4/7/2025
Operational Year 2027
Lead Agency —
Land Use Scale Project/site
Analysis Level for Defaults County
Windspeed (m/s) 2.50
Precipitation (days) 6.00
Location 95 Argonaut, Aliso Viejo, CA 92656, USA
County Orange
City Aliso Viejo
Air District South Coast AQMD
Air Basin South Coast
TAZ 6039
EDFZ 7
Electric Utility Southern California Edison
Gas Utility Southern California Gas
App Version 2022.1.1.29

1.2. Land Use Types
Land Use Subtype Size Unit Lot Acreage Building Area (sq ft) Landscape Area (sq ft)
Special Landscape
Area (sq ft)
Population Description
Condo/Townhouse 61.0 Dwelling Unit 1.92 151,628 27,795 0.00 182 — Appendix A 42 275
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Parking Lot 0.91 Acre 0.91 0.00 0.00 0.00 — —

1.3. User-Selected Emission Reduction Measures by Emissions Sector No measures selected

2. Emissions Summary

2.1. Construction Emissions Compared Against Thresholds Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Un/Mit. TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 48.0 48.0 14.2 15.6 0.03 0.58 4.53 5.04 0.53 1.34 1.88 — 2,766 2,766 0.18 0.06 0.30 2,790 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 48.0 48.0 5.90 7.02 0.01 0.24 0.02 0.26 0.22 < 0.005 0.23 — 1,565 1,565 0.07 0.02 < 0.005 1,573 Average
Daily
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 3.06 3.00 3.72 4.31 0.01 0.15 0.31 0.46 0.14 0.06 0.20 — 916 916 0.05 0.01 0.02 921 Annual
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 0.56 0.55 0.68 0.79 < 0.005 0.03 0.06 0.08 0.02 0.01 0.04 — 152 152 0.01 < 0.005 < 0.005 152

2.2. Construction Emissions by Year, Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Year TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily -
Summer
(Max)
— — — — — — — — — — — — — — — — — —
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2026 1.82 1.48 14.2 15.6 0.03 0.58 4.53 5.04 0.53 1.34 1.88 — 2,766 2,766 0.18 0.06 0.30 2,790 2027 48.0 48.0 5.88 8.41 0.01 0.23 0.02 0.24 0.21 < 0.005 0.21 — 1,565 1,565 0.07 0.02 0.07 1,573 Daily -
Winter
(Max)
— — — — — — — — — — — — — — — — — —
2026 0.86 0.74 5.90 7.02 0.01 0.24 0.02 0.26 0.22 < 0.005 0.23 — 1,565 1,565 0.07 0.02 < 0.005 1,573 2027 48.0 48.0 5.60 6.98 0.01 0.22 0.02 0.24 0.20 < 0.005 0.21 — 1,565 1,565 0.07 0.02 < 0.005 1,572 Average
Daily
— — — — — — — — — — — — — — — — — —
2026 0.52 0.44 3.72 4.31 0.01 0.15 0.31 0.46 0.14 0.06 0.20 — 916 916 0.05 0.01 0.02 921 2027 3.06 3.00 2.87 3.63 0.01 0.11 0.01 0.12 0.10 < 0.005 0.11 — 781 781 0.04 0.01 0.02 785 Annual — — — — — — — — — — — — — — — — — —
2026 0.10 0.08 0.68 0.79 < 0.005 0.03 0.06 0.08 0.02 0.01 0.04 — 152 152 0.01 < 0.005 < 0.005 152 2027 0.56 0.55 0.52 0.66 < 0.005 0.02 < 0.005 0.02 0.02 < 0.005 0.02 — 129 129 0.01 < 0.005 < 0.005 130

2.4. Operations Emissions Compared Against Thresholds
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Un/Mit. TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 4.86 4.81 0.32 6.00 < 0.005 < 0.005 0.15 0.15 < 0.005 0.04 0.04 28.7 698 727 2.98 0.05 1.57 817 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 4.53 4.50 0.31 2.86 < 0.005 < 0.005 0.15 0.15 < 0.005 0.04 0.04 28.7 684 712 2.99 0.05 1.10 802 Average
Daily
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 4.74 4.70 0.33 5.18 < 0.005 < 0.005 0.14 0.15 < 0.005 0.04 0.04 28.7 691 720 2.99 0.05 1.29 810 Annual
(Max)
— — — — — — — — — — — — — — — — — —
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Unmit. 0.87 0.86 0.06 0.95 < 0.005 < 0.005 0.03 0.03 < 0.005 0.01 0.01 4.76 114 119 0.49 0.01 0.21 134

2.5. Operations Emissions by Sector, Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Sector TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Mobile 1.03 1.00 0.29 2.54 < 0.005 < 0.005 0.15 0.15 < 0.005 0.04 0.04 — 218 218 0.06 0.03 0.48 229 Area 3.83 3.81 0.03 3.46 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 0.00 9.25 9.25 < 0.005 < 0.005 — 9.29 Energy 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 454 454 0.04 0.01 — 457 Water — — — — — — — — — — — 4.39 17.0 21.4 0.45 0.01 — 35.9 Waste — — — — — — — — — — — 24.3 0.00 24.3 2.43 0.00 — 85.2 Refrig. — — — — — — — — — — — — — — — — 1.09 1.09
Total 4.86 4.81 0.32 6.00 < 0.005 < 0.005 0.15 0.15 < 0.005 0.04 0.04 28.7 698 727 2.98 0.05 1.57 817 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Mobile 1.02 0.99 0.31 2.86 < 0.005 < 0.005 0.15 0.15 < 0.005 0.04 0.04 — 212 212 0.06 0.03 0.01 224 Area 3.51 3.51 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 Energy 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 454 454 0.04 0.01 — 457 Water — — — — — — — — — — — 4.39 17.0 21.4 0.45 0.01 — 35.9 Waste — — — — — — — — — — — 24.3 0.00 24.3 2.43 0.00 — 85.2 Refrig. — — — — — — — — — — — — — — — — 1.09 1.09
Total 4.53 4.50 0.31 2.86 < 0.005 < 0.005 0.15 0.15 < 0.005 0.04 0.04 28.7 684 712 2.99 0.05 1.10 802 Average
Daily
— — — — — — — — — — — — — — — — — —
Mobile 1.01 0.98 0.31 2.81 < 0.005 < 0.005 0.14 0.15 < 0.005 0.04 0.04 — 214 214 0.06 0.03 0.21 225 Area 3.73 3.72 0.02 2.37 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 0.00 6.34 6.34 < 0.005 < 0.005 — 6.36 Energy 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 454 454 0.04 0.01 — 457 Appendix A 45 278 Argonaut Residential - Localized Emissions Custom Report, 1/31/2025 10 / 41
Water — — — — — — — — — — — 4.39 17.0 21.4 0.45 0.01 — 35.9 Waste — — — — — — — — — — — 24.3 0.00 24.3 2.43 0.00 — 85.2 Refrig. — — — — — — — — — — — — — — — — 1.09 1.09
Total 4.74 4.70 0.33 5.18 < 0.005 < 0.005 0.14 0.15 < 0.005 0.04 0.04 28.7 691 720 2.99 0.05 1.29 810 Annual — — — — — — — — — — — — — — — — — —
Mobile 0.18 0.18 0.06 0.51 < 0.005 < 0.005 0.03 0.03 < 0.005 0.01 0.01 — 35.4 35.4 0.01 0.01 0.03 37.2 Area 0.68 0.68 < 0.005 0.43 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 0.00 1.05 1.05 < 0.005 < 0.005 — 1.05 Energy 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 75.2 75.2 0.01 < 0.005 — 75.6 Water — — — — — — — — — — — 0.73 2.81 3.54 0.07 < 0.005 — 5.95 Waste — — — — — — — — — — — 4.03 0.00 4.03 0.40 0.00 — 14.1 Refrig. — — — — — — — — — — — — — — — — 0.18 0.18
Total 0.87 0.86 0.06 0.95 < 0.005 < 0.005 0.03 0.03 < 0.005 0.01 0.01 4.76 114 119 0.49 0.01 0.21 134

3. Construction Emissions Details

3.1. Demolition (2026) - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Location TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Onsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

1.66 1.39 12.9 14.6 0.02 0.51 — 0.51 0.47 — 0.47 — 2,494 2,494 0.10 0.02 — 2,503 Demoliti
on
— — — — — — 4.49 4.49 — 0.68 0.68 — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Appendix A 46 279
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Daily, — — — — — — — — — — — — — — — — — —
Winter
(Max)
Average
Daily
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.09 0.08 0.71 0.80 < 0.005 0.03 — 0.03 0.03 — 0.03 — 137 137 0.01 < 0.005 — 137 Demoliti
on
— — — — — — 0.25 0.25 — 0.04 0.04 — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Annual — — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.02 0.01 0.13 0.15 < 0.005 0.01 — 0.01 < 0.005 — < 0.005 — 22.6 22.6 < 0.005 < 0.005 — 22.7 Demoliti
on
— — — — — — 0.04 0.04 — 0.01 0.01 — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Offsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.03 0.03 0.01 0.10 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 6.44 6.44 < 0.005 < 0.005 0.02 6.79 Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling 0.13 0.05 1.24 0.88 < 0.005 < 0.005 0.04 0.04 < 0.005 0.01 0.01 — 265 265 0.07 0.04 0.28 280 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Average
Daily
— — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 0.01 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 0.35 0.35 < 0.005 < 0.005 < 0.005 0.36 Appendix A 47 280
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Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling 0.01 < 0.005 0.07 0.05 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 14.6 14.6 < 0.005 < 0.005 0.01 15.4 Annual — — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 < 0.005 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 0.06 0.06 < 0.005 < 0.005 < 0.005 0.06 Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling < 0.005 < 0.005 0.01 0.01 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 2.42 2.42 < 0.005 < 0.005 < 0.005 2.55

3.3. Site Preparation (2026) - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Location TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Onsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

1.34 1.13 9.84 10.8 0.03 0.42 — 0.42 0.39 — 0.39 — 2,716 2,716 0.11 0.02 — 2,725 Dust
From
Material
Movement
— — — — — — 0.62 0.62 — 0.07 0.07 — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Average
Daily
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.01 0.01 0.08 0.09 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 22.3 22.3 < 0.005 < 0.005 — 22.4 Appendix A 48 281
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Dust — — — — — — 0.01 0.01 — < 0.005 < 0.005 — — — — — — — From
Material
Movement
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Annual — — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent
< 0.005 < 0.005 0.01 0.02 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 3.70 3.70 < 0.005 < 0.005 — 3.71 Dust
From
Material
Movement
— — — — — — < 0.005 < 0.005 — < 0.005 < 0.005 — — — — — — — Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Offsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.02 0.02 < 0.005 0.06 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 3.87 3.87 < 0.005 < 0.005 0.01 4.08 Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Average
Daily
— — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 < 0.005 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 0.03 0.03 < 0.005 < 0.005 < 0.005 0.03 Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Annual — — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 < 0.005 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 0.01 0.01 < 0.005 < 0.005 < 0.005 0.01 Appendix A 49 282
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Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00

3.5. Grading (2026) - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Location TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Onsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

1.70 1.42 12.9 14.0 0.02 0.58 — 0.58 0.53 — 0.53 — 2,455 2,455 0.10 0.02 — 2,463 Dust
From
Material
Movement
— — — — — — 2.77 2.77 — 1.34 1.34 — — — — — — —
Onsite
truck

0.03 0.02 0.21 0.23 < 0.005 0.01 — 0.01 0.01 — 0.01 — 40.4 40.4 < 0.005 < 0.005 — 40.5 Dust
From
Material
Movement
— — — — — — 0.05 0.05 — 0.02 0.02 — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Appendix A 50 283
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Annual — — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.01 < 0.005 0.04 0.04 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 6.68 6.68 < 0.005 < 0.005 — 6.70 Dust
From
Material
Movement
— — — — — — 0.01 0.01 — < 0.005 < 0.005 — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Offsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.03 0.03 0.01 0.08 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 5.15 5.15 < 0.005 < 0.005 0.01 5.44 Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling 0.08 0.03 0.76 0.54 < 0.005 < 0.005 0.02 0.02 < 0.005 0.01 0.01 — 163 163 0.05 0.03 0.17 173 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Average
Daily
— — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 < 0.005 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 0.08 0.08 < 0.005 < 0.005 < 0.005 0.09 Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling < 0.005 < 0.005 0.01 0.01 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 2.69 2.69 < 0.005 < 0.005 < 0.005 2.84 Annual — — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 < 0.005 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 0.01 0.01 < 0.005 < 0.005 < 0.005 0.01 Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 0.45 0.45 < 0.005 < 0.005 < 0.005 0.47

3.7. Building Construction (2026) - Unmitigated
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Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Location TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Onsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.74 0.62 5.80 6.58 0.01 0.24 — 0.24 0.22 — 0.22 — 1,527 1,527 0.06 0.01 — 1,532 Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.74 0.62 5.80 6.58 0.01 0.24 — 0.24 0.22 — 0.22 — 1,527 1,527 0.06 0.01 — 1,532 Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Average
Daily
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.33 0.28 2.59 2.93 0.01 0.11 — 0.11 0.10 — 0.10 — 681 681 0.03 0.01 — 683 Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Annual — — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.06 0.05 0.47 0.54 < 0.005 0.02 — 0.02 0.02 — 0.02 — 113 113 < 0.005 < 0.005 — 113 Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Appendix A 52 285
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Offsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.12 0.11 0.03 0.35 0.00 0.00 0.02 0.02 0.00 < 0.005 < 0.005 — 22.6 22.6 0.01 < 0.005 0.05 23.9 Vendor 0.01 < 0.005 0.07 0.05 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 16.1 16.1 < 0.005 < 0.005 0.03 16.9 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.12 0.11 0.03 0.39 0.00 0.00 0.02 0.02 0.00 < 0.005 < 0.005 — 22.0 22.0 0.01 < 0.005 < 0.005 23.2 Vendor 0.01 < 0.005 0.07 0.05 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 16.2 16.2 < 0.005 < 0.005 < 0.005 17.0 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Average
Daily
— — — — — — — — — — — — — — — — — —
Worker 0.05 0.05 0.01 0.17 0.00 0.00 0.01 0.01 0.00 < 0.005 < 0.005 — 9.90 9.90 < 0.005 < 0.005 0.01 10.4 Vendor < 0.005 < 0.005 0.03 0.02 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 7.20 7.20 < 0.005 < 0.005 < 0.005 7.55 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Annual — — — — — — — — — — — — — — — — — —
Worker 0.01 0.01 < 0.005 0.03 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 1.64 1.64 < 0.005 < 0.005 < 0.005 1.73 Vendor < 0.005 < 0.005 0.01 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 1.19 1.19 < 0.005 < 0.005 < 0.005 1.25 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00

3.9. Building Construction (2027) - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Location TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Onsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
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Off-Roa 0.72 0.60 5.51 6.56 0.01 0.22 — 0.22 0.20 — 0.20 — 1,527 1,527 0.06 0.01 — 1,532 d
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.72 0.60 5.51 6.56 0.01 0.22 — 0.22 0.20 — 0.20 — 1,527 1,527 0.06 0.01 — 1,532 Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Average
Daily
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.33 0.27 2.50 2.98 0.01 0.10 — 0.10 0.09 — 0.09 — 693 693 0.03 0.01 — 695 Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Annual — — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.06 0.05 0.46 0.54 < 0.005 0.02 — 0.02 0.02 — 0.02 — 115 115 < 0.005 < 0.005 — 115 Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Offsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.11 0.11 0.03 0.32 0.00 0.00 0.02 0.02 0.00 < 0.005 < 0.005 — 22.2 22.2 0.01 < 0.005 0.05 23.4 Vendor 0.01 < 0.005 0.06 0.05 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 15.8 15.8 < 0.005 < 0.005 0.02 16.6 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Appendix A 54 287
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Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.11 0.11 0.03 0.37 0.00 0.00 0.02 0.02 0.00 < 0.005 < 0.005 — 21.6 21.6 0.01 < 0.005 < 0.005 22.8 Vendor 0.01 < 0.005 0.07 0.05 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 15.9 15.9 < 0.005 < 0.005 < 0.005 16.7 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Average
Daily
— — — — — — — — — — — — — — — — — —
Worker 0.05 0.05 0.01 0.16 0.00 0.00 0.01 0.01 0.00 < 0.005 < 0.005 — 9.88 9.88 < 0.005 < 0.005 0.01 10.4 Vendor < 0.005 < 0.005 0.03 0.02 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 7.21 7.21 < 0.005 < 0.005 < 0.005 7.56 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Annual — — — — — — — — — — — — — — — — — —
Worker 0.01 0.01 < 0.005 0.03 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 1.64 1.64 < 0.005 < 0.005 < 0.005 1.73 Vendor < 0.005 < 0.005 0.01 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 1.19 1.19 < 0.005 < 0.005 < 0.005 1.25 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00

3.11. Paving (2027) - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Location TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Onsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.77 0.65 5.74 8.20 0.01 0.23 — 0.23 0.21 — 0.21 — 1,244 1,244 0.05 0.01 — 1,248 Paving 0.12 0.12 — — — — — — — — — — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Appendix A 55 288
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Daily, — — — — — — — — — — — — — — — — — —
Winter
(Max)
Average
Daily
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.04 0.04 0.31 0.45 < 0.005 0.01 — 0.01 0.01 — 0.01 — 68.2 68.2 < 0.005 < 0.005 — 68.4 Paving 0.01 0.01 — — — — — — — — — — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Annual — — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.01 0.01 0.06 0.08 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 11.3 11.3 < 0.005 < 0.005 — 11.3 Paving < 0.005 < 0.005 — — — — — — — — — — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Offsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.04 0.04 0.01 0.11 0.00 0.00 0.01 0.01 0.00 < 0.005 < 0.005 — 7.59 7.59 < 0.005 < 0.005 0.02 8.00 Vendor 0.01 0.01 0.14 0.10 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 28.9 28.9 0.01 < 0.005 0.03 30.6 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Average
Daily
— — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 0.01 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 0.41 0.41 < 0.005 < 0.005 < 0.005 0.43 Vendor < 0.005 < 0.005 0.01 0.01 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 1.59 1.59 < 0.005 < 0.005 < 0.005 1.68 Appendix A 56 289
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Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Annual — — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 < 0.005 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 0.07 0.07 < 0.005 < 0.005 < 0.005 0.07 Vendor < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 0.26 0.26 < 0.005 < 0.005 < 0.005 0.28 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00

3.13. Architectural Coating (2027) - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Location TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Onsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 0.00 0.00 0.00 0.00 — 0.00 Architect
ural
Coating
s

48.0 48.0 — — — — — — — — — — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 0.00 0.00 0.00 0.00 — 0.00 Architect
ural
Coating
s

48.0 48.0 — — — — — — — — — — — — — — — —
Appendix A 57 290
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Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Average
Daily
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 0.00 0.00 0.00 0.00 — 0.00 Architect
ural
Coating
s

2.63 2.63 — — — — — — — — — — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Annual — — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 0.00 0.00 0.00 0.00 — 0.00 Architect
ural
Coating
s

0.48 0.48 — — — — — — — — — — — — — — — —
Onsite
truck

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Offsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.02 0.02 0.01 0.06 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 4.45 4.45 < 0.005 < 0.005 0.01 4.69 Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.02 0.02 0.01 0.07 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 4.32 4.32 < 0.005 < 0.005 < 0.005 4.55 Appendix A 58 291 Argonaut Residential - Localized Emissions Custom Report, 1/31/2025 23 / 41
Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Average
Daily
— — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 < 0.005 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 0.24 0.24 < 0.005 < 0.005 < 0.005 0.25 Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Annual — — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 < 0.005 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 0.04 0.04 < 0.005 < 0.005 < 0.005 0.04 Vendor 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Hauling 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00

4. Operations Emissions Details

4.1. Mobile Emissions by Land Use

4.1.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Condo/T
ownhou
se

1.03 1.00 0.29 2.54 < 0.005 < 0.005 0.15 0.15 < 0.005 0.04 0.04 — 218 218 0.06 0.03 0.48 229 Parking
Lot

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Total 1.03 1.00 0.29 2.54 < 0.005 < 0.005 0.15 0.15 < 0.005 0.04 0.04 — 218 218 0.06 0.03 0.48 229 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
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Condo/T 1.02 0.99 0.31 2.86 < 0.005 < 0.005 0.15 0.15 < 0.005 0.04 0.04 — 212 212 0.06 0.03 0.01 224 Parking
Lot

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Total 1.02 0.99 0.31 2.86 < 0.005 < 0.005 0.15 0.15 < 0.005 0.04 0.04 — 212 212 0.06 0.03 0.01 224 Annual — — — — — — — — — — — — — — — — — —
Condo/T
ownhou
se

0.18 0.18 0.06 0.51 < 0.005 < 0.005 0.03 0.03 < 0.005 0.01 0.01 — 35.4 35.4 0.01 0.01 0.03 37.2 Parking
Lot

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Total 0.18 0.18 0.06 0.51 < 0.005 < 0.005 0.03 0.03 < 0.005 0.01 0.01 — 35.4 35.4 0.01 0.01 0.03 37.2

4.2. Energy

4.2.1. Electricity Emissions By Land Use - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Condo/T
ownhou
se
— — — — — — — — — — — — 421 421 0.04 < 0.005 — 424
Parking
Lot
— — — — — — — — — — — — 32.9 32.9 < 0.005 < 0.005 — 33.1 Total — — — — — — — — — — — — 454 454 0.04 0.01 — 457
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Condo/T
ownhou
se
— — — — — — — — — — — — 421 421 0.04 < 0.005 — 424
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Parking — — — — — — — — — — — — 32.9 32.9 < 0.005 < 0.005 — 33.1 Lot
Total — — — — — — — — — — — — 454 454 0.04 0.01 — 457
Annual — — — — — — — — — — — — — — — — — —
Condo/T
ownhou
se
— — — — — — — — — — — — 69.7 69.7 0.01 < 0.005 — 70.1
Parking
Lot
— — — — — — — — — — — — 5.45 5.45 < 0.005 < 0.005 — 5.48 Total — — — — — — — — — — — — 75.2 75.2 0.01 < 0.005 — 75.6

4.2.3. Natural Gas Emissions By Land Use - Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Condo/T
ownhou
se

0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 0.00 0.00 0.00 0.00 — 0.00 Parking
Lot

0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 0.00 0.00 0.00 0.00 — 0.00 Total 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 0.00 0.00 0.00 0.00 — 0.00 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Condo/T
ownhou
se

0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 0.00 0.00 0.00 0.00 — 0.00 Parking
Lot

0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 0.00 0.00 0.00 0.00 — 0.00 Total 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 0.00 0.00 0.00 0.00 — 0.00 Annual — — — — — — — — — — — — — — — — — — Appendix A 61 294 Argonaut Residential - Localized Emissions Custom Report, 1/31/2025 26 / 41
Condo/T 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 0.00 0.00 0.00 0.00 — 0.00 Parking
Lot

0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 0.00 0.00 0.00 0.00 — 0.00 Total 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 — 0.00 0.00 0.00 0.00 — 0.00

4.3. Area Emissions by Source

4.3.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Source TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Hearths 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 Consum
er
Product
s

3.25 3.25 — — — — — — — — — — — — — — — —
Architect
ural
Coating
s

0.26 0.26 — — — — — — — — — — — — — — — —
Landsca
pe
Equipm
ent

0.32 0.30 0.03 3.46 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 9.25 9.25 < 0.005 < 0.005 — 9.29 Total 3.83 3.81 0.03 3.46 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 0.00 9.25 9.25 < 0.005 < 0.005 — 9.29 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Hearths 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 Consum
er
Product
s

3.25 3.25 — — — — — — — — — — — — — — — —
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Architect
Coatings

0.26 0.26 — — — — — — — — — — — — — — — —
Total 3.51 3.51 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 Annual — — — — — — — — — — — — — — — — — —
Hearths 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 Consum
er
Product
s

0.59 0.59 — — — — — — — — — — — — — — — —
Architect
ural
Coating
s

0.05 0.05 — — — — — — — — — — — — — — — —
Landsca
pe
Equipm
ent

0.04 0.04 < 0.005 0.43 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 1.05 1.05 < 0.005 < 0.005 — 1.05 Total 0.68 0.68 < 0.005 0.43 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 0.00 1.05 1.05 < 0.005 < 0.005 — 1.05

4.4. Water Emissions by Land Use

4.4.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Condo/T
ownhou
se
— — — — — — — — — — — 4.39 17.0 21.4 0.45 0.01 — 35.9
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 4.39 17.0 21.4 0.45 0.01 — 35.9 Appendix A 63 296
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Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Condo/T
ownhou
se
— — — — — — — — — — — 4.39 17.0 21.4 0.45 0.01 — 35.9
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 4.39 17.0 21.4 0.45 0.01 — 35.9 Annual — — — — — — — — — — — — — — — — — —
Condo/T
ownhou
se
— — — — — — — — — — — 0.73 2.81 3.54 0.07 < 0.005 — 5.95 Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 0.73 2.81 3.54 0.07 < 0.005 — 5.95

4.5. Waste Emissions by Land Use

4.5.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Condo/T
ownhou
se
— — — — — — — — — — — 24.3 0.00 24.3 2.43 0.00 — 85.2
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 24.3 0.00 24.3 2.43 0.00 — 85.2 Appendix A 64 297
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Daily, — — — — — — — — — — — — — — — — — —
Winter
(Max)
Condo/T
ownhou
se
— — — — — — — — — — — 24.3 0.00 24.3 2.43 0.00 — 85.2
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 24.3 0.00 24.3 2.43 0.00 — 85.2 Annual — — — — — — — — — — — — — — — — — —
Condo/T
ownhou
se
— — — — — — — — — — — 4.03 0.00 4.03 0.40 0.00 — 14.1
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 4.03 0.00 4.03 0.40 0.00 — 14.1

4.6. Refrigerant Emissions by Land Use

4.6.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Condo/T
ownhou
se
— — — — — — — — — — — — — — — — 1.09 1.09
Total — — — — — — — — — — — — — — — — 1.09 1.09
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Appendix A 65 298
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Condo/T — — — — — — — — — — — — — — — — 1.09 1.09
ownhou
Total — — — — — — — — — — — — — — — — 1.09 1.09
Annual — — — — — — — — — — — — — — — — — —
Condo/T
ownhou
se
— — — — — — — — — — — — — — — — 0.18 0.18
Total — — — — — — — — — — — — — — — — 0.18 0.18

4.7. Offroad Emissions By Equipment Type

4.7.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Equipm
ent
Type
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.8. Stationary Emissions By Equipment Type

4.8.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Appendix A 66 299
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Equipm TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e ent
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.9. User Defined Emissions By Equipment Type

4.9.1. Unmitigated
Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Equipm
ent
Type
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.10. Soil Carbon Accumulation By Vegetation Type
Appendix A 67 300
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4.10.1. Soil Carbon Accumulation By Vegetation Type - Unmitigated Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Vegetati
on
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.10.2. Above and Belowground Carbon Accumulation by Land Use Type - Unmitigated Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Land
Use
TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.10.3. Avoided and Sequestered Emissions by Species - Unmitigated Appendix A 68 301
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Criteria Pollutants (lb/day for daily, ton/yr for annual) and GHGs (lb/day for daily, MT/yr for annual) Species TOG ROG NOx CO SO2 PM10E PM10D PM10T PM2.5E PM2.5D PM2.5T BCO2 NBCO2 CO2T CH4 N2O R CO2e Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — — Appendix A 69 302 Argonaut Residential - Localized Emissions Custom Report, 1/31/2025 34 / 41
Remove — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —

5. Activity Data

5.1. Construction Schedule
Phase Name Phase Type Start Date End Date Days Per Week Work Days per Phase Phase Description Demolition Demolition 4/6/2026 5/1/2026 5.00 20.0 —
Site Preparation Site Preparation 5/4/2026 5/6/2026 5.00 3.00 — Grading Grading 5/7/2026 5/14/2026 5.00 6.00 —
Building Construction Building Construction 5/18/2026 8/20/2027 5.00 330 Default Length increased from 220 to 200
Paving Paving 8/23/2027 9/17/2027 5.00 20.0 Length Doubled from Default Length
Architectural Coating Architectural Coating 9/20/2027 10/15/2027 5.00 20.0 Length Doubled from Default Lengtth

5.2. Off-Road Equipment

5.2.1. Unmitigated
Phase Name Equipment Type Fuel Type Engine Tier Number per Day Hours Per Day Horsepower Load Factor Demolition Concrete/Industrial
Saws
Diesel Average 1.00 8.00 33.0 0.73
Demolition Rubber Tired Dozers Diesel Average 1.00 8.00 367 0.40 Demolition Tractors/Loaders/Back
hoes
Diesel Average 3.00 8.00 84.0 0.37
Site Preparation Graders Diesel Average 1.00 8.00 148 0.41 Site Preparation Scrapers Diesel Average 1.00 8.00 423 0.48 Appendix A 70 303
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Site Preparation Tractors/Loaders/Back Diesel Average 1.00 7.00 84.0 0.37 hoes
Grading Graders Diesel Average 1.00 8.00 148 0.41
Grading Rubber Tired Dozers Diesel Average 1.00 8.00 367 0.40 Grading Tractors/Loaders/Back
hoes
Diesel Average 2.00 7.00 84.0 0.37
Building Construction Cranes Diesel Average 1.00 8.00 367 0.29 Building Construction Forklifts Diesel Average 2.00 7.00 82.0 0.20 Building Construction Generator Sets Diesel Average 1.00 4.00 14.0 0.74 Building Construction Tractors/Loaders/Back
hoes
Diesel Average 1.00 6.00 84.0 0.37
Building Construction Welders Electric Average 3.00 8.00 46.0 0.45 Paving Cement and Mortar
Mixers
Diesel Average 1.00 8.00 10.0 0.56
Paving Pavers Diesel Average 1.00 8.00 81.0 0.42
Paving Paving Equipment Diesel Average 1.00 8.00 89.0 0.36 Paving Rollers Diesel Average 2.00 8.00 36.0 0.38
Paving Tractors/Loaders/Back
hoes
Diesel Average 1.00 8.00 84.0 0.37
Architectural Coating Air Compressors Electric Average 1.00 6.00 37.0 0.48

5.3. Construction Vehicles

5.3.1. Unmitigated
Phase Name Trip Type One-Way Trips per Day Miles per Trip Vehicle Mix Demolition — — — —
Demolition Worker 12.5 0.50 LDA,LDT1,LDT2
Demolition Vendor — 0.50 HHDT,MHDT
Demolition Hauling 81.3 0.50 HHDT
Demolition Onsite truck — — HHDT
Appendix A 71 304
Argonaut Residential - Localized Emissions Custom Report, 1/31/2025 36 / 41
Site Preparation — — — —
Site Preparation Worker 7.50 0.50 LDA,LDT1,LDT2
Site Preparation Vendor — 0.50 HHDT,MHDT
Site Preparation Hauling 0.00 0.50 HHDT
Site Preparation Onsite truck — — HHDT
Grading — — — —
Grading Worker 10.0 0.50 LDA,LDT1,LDT2
Grading Vendor — 0.50 HHDT,MHDT
Grading Hauling 50.0 0.50 HHDT
Grading Onsite truck — — HHDT
Building Construction — — — —
Building Construction Worker 43.9 0.50 LDA,LDT1,LDT2
Building Construction Vendor 6.52 0.50 HHDT,MHDT
Building Construction Hauling 0.00 0.50 HHDT
Building Construction Onsite truck — — HHDT
Paving — — — —
Paving Worker 15.0 0.50 LDA,LDT1,LDT2
Paving Vendor 9.00 0.50 HHDT
Paving Hauling 0.00 0.50 HHDT
Paving Onsite truck 0.00 0.50 HHDT
Architectural Coating — — — —
Architectural Coating Worker 8.78 0.50 LDA,LDT1,LDT2
Architectural Coating Vendor — 0.50 HHDT,MHDT
Architectural Coating Hauling 0.00 0.50 HHDT
Architectural Coating Onsite truck — — HHDT

5.4. Vehicles
Appendix A 72 305
Argonaut Residential - Localized Emissions Custom Report, 1/31/2025 37 / 41

5.4.1. Construction Vehicle Control Strategies
Non-applicable. No control strategies activated by user.

5.6. Dust Mitigation

5.6.2. Construction Earthmoving Control Strategies
Control Strategies Applied Frequency (per day) PM10 Reduction PM2.5 Reduction Water Exposed Area 2 61% 61%
Water Demolished Area 2 36% 36%

5.7. Construction Paving
Land Use Area Paved (acres) % Asphalt
Condo/Townhouse — 0%
Parking Lot 0.91 100%
Appendix A 73 306
Argonaut Residential - Localized Emissions Custom Report, 1/31/2025 38 / 41

5.8. Construction Electricity Consumption and Emissions Factors kWh per Year and Emission Factor (lb/MWh)
Year kWh per Year CO2 CH4 N2O
2026 370 346 0.03 < 0.005
2027 450 346 0.03 < 0.005

5.9. Operational Mobile Sources

5.9.1. Unmitigated
Land Use Type Trips/Weekday Trips/Saturday Trips/Sunday Trips/Year VMT/Weekday VMT/Saturday VMT/Sunday VMT/Year Condo/Townhouse 411 411 411 150,066 206 206 206 75,033
Parking Lot 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

5.10. Operational Area Sources

5.10.1. Hearths

5.10.1.1. Unmitigated
Hearth Type Unmitigated (number)
Condo/Townhouse —
Wood Fireplaces 0
Gas Fireplaces 0
Propane Fireplaces 0
Electric Fireplaces 0
No Fireplaces 61
Conventional Wood Stoves 0
Catalytic Wood Stoves 0
Non-Catalytic Wood Stoves Appendix A 0 74 307
Argonaut Residential - Localized Emissions Custom Report, 1/31/2025 39 / 41
Pellet Wood Stoves 0

5.10.3. Landscape Equipment
Season Unit Value
Snow Days day/yr 0.00
Summer Days day/yr 250

5.11. Operational Energy Consumption

5.12. Operational Water and Wastewater Consumption

5.12.1. Unmitigated
Land Use Indoor Water (gal/year) Outdoor Water (gal/year) Condo/Townhouse 2,289,065 440,285
Parking Lot 0.00 0.00
Appendix A 75 308
Argonaut Residential - Localized Emissions Custom Report, 1/31/2025 40 / 41

5.13. Operational Waste Generation

5.13.1. Unmitigated
Land Use Waste (ton/year) Cogeneration (kWh/year)
Condo/Townhouse 45.2 —
Parking Lot 0.00 —

5.14. Operational Refrigeration and Air Conditioning Equipment

8. User Changes to Default Data
Screen Justification
Land Use Bldg Square footage is Gross for construction purposes and conservatively based on 3 story buildings at a site coverage 41 % (this estimate would include unconditioned built space such as garages, porches etc)
Landscaping from site plans
Parking represents interior roads and parking and calculated by subtracting building footprint/coverage and open space 33,092 sq ft
Construction: Construction Phases Building construction phases increased based on applicants schedule and density of the construction
Assume that on-site electricity is available for uses such as welding - air compressors and temporary power used in lieu of diesel generators
Construction: Off-Road Equipment Generator Reduced to 4 hours per day to reflect grid/temp power Appendix A Air Compressors and Welders - Electric 76 309 Argonaut Residential - Localized Emissions Custom Report, 1/31/2025 41 / 41
Operations: Energy Use Calculational Method is from Measure E-15 of the CAPCOA Handbook for Analyzing Greenhouse Gas Emission Reductions, Assessing Climate Vulnerabilities, and Advancing Health
Construction: Trips and VMT Vendor Paving trips for asphalt Trip Length 0.5 mile for LST
Operations: Vehicle Data Trip Length 0.5 mile for LST
Trip Generation Rates from Urban Crossroads Reports (June and July 2024) for Trip Generation and VMT Screening
Operations: Hearths No Woodstoves or Fireplaces
Appendix A 77 310
Argonaut Residential
Demolition Debris Calculations
Description Footprint Area 1
(square feet)
height/depth
(ft)
Volume
(ft3)
Demolition Waste
Fraction
Demolition
Volume1 (ft3)
Demolition Waste
Density (tons/cy)
Demolition
Weight
(tons)
Building (2-story) 24,000 25 600,000 0.25 150,000 0.50 2,778 Pavement 99,275 0.5 49,637 1 49,637 2.025 3,723
Totals 123,275 - - - 6,500
Notes:
1 Source: Site Plans - Pervious Areas removed. Conservatively used as Bldg Square Footage for Demoltion Estimates.

Building demolition estimates are based on methods used in CalEEMod (CAPCOA, 2022), based on 1 story building , assume 10 ft per floor where 1 sf = 10 cf of building volume, and 1 cf of building volume = 0.25 cf of waste. This approach can be used to estimate demolition for multiple story buildings. It also assumes 1 cubic yard building waste = 0.5 ton weight 1 cubic yard of asphalt = 2.025 tons or 4050 lbs.

Appendix A 78 311
Argonaut Residential
Asphalt Paving Construction Trips Calculation
Paved area including driveways (acres)
Paved area (sf) 39,640
Asphalt volume (cube feet) assume 6 inch pavement 19,820 Asphalt volume (cy) 734
Capacity per vendor truck (CY per truck) 16
One-Way Trips 92
Days in paving phase 10
One-way Vendor Trips per day 9
Appendix A 79 312
Argonaut Residential
All-Electric Measure Electricity Adjustment to Replace NG Usage CEC Electricity Demand Forecast Zone (EDFZ) 7
Water Primary Cooking Dryer
TOTAL per Unit) (per Unit)
Title 24
(per Unit)
Non-Title 24
Total CalEEMod
Value
Subject to
Title 24
Not Subject to
Title 24
Total CalEEMod
Value
Subject to
Title 24
Not Subject to Title
24 Building Type / LandUse Amount Units Heater Heat kWhr/yr kWhr/yr kWhr/yr kWhr/yr kWhr/yr Condo/Townhouse 61 Dwelling Units 1365 609 292 422 2,688 1,974 714 280,122 69,046 211,076 444,090 189,460 254,630 Parking Lot 39.640 1,000 sqft 0 34,725 34,725 0
Calculational Method is from Measure E-15 of the CAPCOA Handbook for Analyzing Greenhouse Gas Emission Reductions, Assessing Climate Vulnerabilities, and Advancing Health and Equity Emission Factors are From Data Tables E=15.2 from Appendix C of the Handbook References:

CAPCOA, 2021. Handbook for Analyzing Greenhouse Gas Emission Reductions, Assessing Climate Vulnerabilities, and Advancing Health and Equity. Available at: Available at: https://www.airquality.org/ClimateChange/Documents/Final%20Handbook_AB434.pdf.

CAPCOA. 2021. Appendix C : Emission Factors and Data Tables from Handbook for Analyzing Greenhouse Gas Emission Reductions, Assessing Climate Vulnerabilities, and Advancing Health and Equity.. Available at: https://www.caleemod.com/documents/handbook/appendices/appendix_c.pdf Electric End Use per Unit (DU or KSF) Additional Energy for Replaced End Uses Caleemod DEFAULT Electricity Usage
kWhr/yr ALL Electtric Project REVISED Electricity KWhr-Year Appendix A 80 313
Argonaut Residential
Modeling Parameters for Construction HRA
Diesel Particulate Matter Emission Sources
SITE Site - Off-Road Equipment Diesel Exhaust1
Project Site - Construction Area Area 11468.4 m2 5 — 1.4 0.0298 3.27E-07 g/m2-sec ROAD1 Roadway 1 - On-Road Diesel Exhaust 2,3 Truck Route - Glenwood Drive Line-Volume 957 meters 3.40 7.44 3.16 2.8E-05 3.53E-06 g/s Monday - Friday
1-6 0 0 0 0 0 0
7-12 0 0 1 1 1 1
13-18 0 1 1 1 1 0
19-24 0 0 0 0 0 0
Saturday
1-6 0 0 0 0 0 0
7-12 0 0 0 0 0 0
13-18 0 0 0 0 0 0
19-24 0 0 0 0 0 0
Sunday
1-6 0 0 0 0 0 0
7-12 0 0 0 0 0 0
13-18 0 0 0 0 0 0
19-24 0 0 0 0 0 0
4 Emissions from CalEEModeling for Construction modeled during construction hours as included in Attachment A. See Note 2 above regarding roadway emission portion modeled.

Source ID
Emissions4
(lb/hr)
AERMOD Source
Emission Rate
Variable Emission Factors: ALL Sources
1 Construction exhaust modeled as an area source. Release parameters for construction equipment DPM exhaust modeling from SCAQMD (2008) for gaseous exhaust from construction equipment.
2 Emissions for On-Road Mobile Sources (Vendor and Haul Diesel Exhaust) modeled only for roadways within 1,000 feet of the site within the modeling domain. 3 Parameters calculated as per US EPA Haul Road Workgroup Final Report released on March 2, 2012 which suggests the use of Adjacent Volume Sources to represent the haul road.

Initial Source Release Parameters (m)
Modeled Source Location Description
AERMOD
Source Type Size
Release
Height
Initial Lateral
Dimension
Initial
Vertical
Dimension
Appendix A 81 314
Argonaut Residential
Health Risk Assessment Inputs
DPM Emissions for AERMOD Inputs
Net Work Days 399
Net Construction Years 1.53
Total Working Hours 3,192
Worker Vendor Haul
2026 Demolition 10.17 1.43 - - 1.43
2026 Site Preparation 1.27 0.00 - - -
2026 Grading 3.47 0.26 - - 0.26
2026 Building Construction 39.07 0.24 - 0.239 -
2026 Building Construction 36.39 0.24 - 0.243 -
2027 Paving 4.60 0.16 - - 0.16
2027 Architectural Coating 0.00 0.00 - - -

94.97 2.34 - 0.48 1.856
Note: PM10E = PM10 Exhaust which is a surrogate for Diesel Exhaust, particulate matter

11.7 8.4 20

0.59 0.59 0.59
5% 7% 3%
`
` Worker Vendor Haul
Modeled Emissions (lbs) 94.97 0.089 - 0.03 0.06
Hourly Emissions (lb/hr) 0.0298 0.00003 0.00E+00 1.07E-05 1.73E-05 Source percentage
Site Emissions 100% 2.98E-02 lb/hr
Roadway 1 Emissions 100% 2.80E-05 lb/hr
Modeling Inputs
Roadway Emissions included
Off-Site PM10E Off-Site PM10E(lbs)
(lbs)
Offsite Roadway
Off-Site Diesel PM10E (lbs)
within 1,000 ft Roadways
CalEEMod Distance (miles)
Total Roadways Included within 1,000 ft
Total PM Exhaust (On-site)
On-site
Construction
Construction Year On-site Construction Activity On-site PM10E (lbs)
Appendix A 82 315
PROJECT TITLE:

Argonaut Residential Project
Construction HRA - Source and Receptors
Source Legend:

Site Boundary ------
Site ■
Haul Road ⛝⛝⛝
Receptor Legend:
● Residential
● Near Residential
● Commercial / Retail
● Park / Open Space
Sources / Receptors :
2 / 236
SCALE: 1:7,500
0 0.2 km
AERMOD View - Lakes Environmental Software
Appendix A 83 316
WIND ROSE PLOT: DISPLAY:

Mission Viejo Station (MSVJ) Wind Speed
Wind Direction during Construction Hours Direction (blowing from) NORTH

13.1%

10.5%

7.86%

5.24%

2.62%

WEST EAST

WIND SPEED
(m/s)
>= 11.10

8.80 - 11.10

5.70 - 8.80
SOUTH 3.60 - 5.70

2.10 - 3.60

0.50 - 2.10
Calms: 0.56%
COMMENTS:

Wind Rose is generated just for the
hours with emissions when
construction would occur or from
8 AM – 5 PM. This corresponds to the
modeling hours in AERMOD.

DATA PERIOD:

Start Date: 1/1/2017 - 09:00
End Date: 12/31/2021 - 17:00
How to Read a Wind Rose Diagram
The wind rose above shows the general wind direction
and speed for the meteorological data set used in the
AERMOD modeling for the project.’
The circular format of the wind rose shows the direction the winds blew from and the length of each "spoke"
around the circle shows how often the wind blew from
that direction.

CALM WINDS:

0.56%
AVG. WIND SPEED:

1.96 m/s
WRPLOT View - Lakes Environmental Software
Appendix A 84 317
PROJECT TITLE:

Argonaut Residential Project - Construction HRA
Maximum Impact Location
Source Legend:

Site
Boundary ------
Site ■
Receptor Legend:
● Residential
● Near Residential
● Commercial / Retail
● Park / Open Space
Sensitive Receptor Legend:
▲ MEIR = Maximally Exposed Individual Resident
▲ MEIW = Maximally Exposed Individual Worker
SCALE
1:7,500
0 0.2 km
AERMOD View - Lakes Environmental Software
MEIW ▲
85 318
Control Pathway
AERMOD
Total Deposition (Dry & Wet)
Dry Deposition
Wet Deposition
Output Type
Concentration
Regulatory Default Non-Default Options
Dispersion Options
Argonaut Residential Project
Construction HRA - DPM
Titles
Dispersion Options
Population:

Name (Optional):

Roughness Length:

Plume Depletion
Dry Removal
Wet Removal
Output Warnings
No Output Warnings
Non-fatal Warnings for Non-sequential Met Data
Dispersion Coefficient
Urban
Pollutant / Averaging Time / Terrain Options
TG: Meters
RE: Meters
1 2 3 4 6 8 12 24 Flat Elevated SO: Meters
Hours Terrain Height Options
Averaging Time Options
Option not available Half Life of 4 hrs will be used
Pollutant Type Exponential Decay
Month Period Annual
PM10
Flagpole Receptors
Yes No
Default Height = 0.00 m
Appendix A 86 319
Control Pathway
AERMOD
Optional Files
Re-Start File Init File Multi-Year Analyses Event Input File Error Listing File Detailed Error Listing File
Filename: ConHRA.err
Appendix A 87 320
Source Pathway - Source Inputs
AERMOD
Polygon Area Sources
Source Type: AREA POLY
Source: SITE (Construction Site)
X Coordinate
for Vertices
[m]
Y Coordinate
for Vertices
[m]
Base
Elevation
(Optional)
Emission
Rate
[g/ (s-m^2)]
Release
Height
[m]
Initial
Vertical
Dim. [m]
Number of
Vertices
(or sides)
135.99 5.00 3.27E-7 1.40 18 432852.37 3717489.75

3.27E-7 432849.58 3717501.17

3.27E-7 432717.68 3717473.69

3.27E-7 432716.80 3717473.95

3.27E-7 432713.57 3717467.44

3.27E-7 432731.86 3717385.04

3.27E-7 432734.07 3717382.84

3.27E-7 432735.90 3717380.63

3.27E-7 432739.58 3717379.90

3.27E-7 432762.72 3717385.04

3.27E-7 432778.15 3717390.55

3.27E-7 432787.34 3717392.39

3.27E-7 432797.99 3717385.77

3.27E-7 432848.13 3717436.03

3.27E-7 432845.02 3717447.87

3.27E-7 432843.18 3717461.83

3.27E-7 432843.18 3717471.01

3.27E-7 432846.86 3717482.77
Appendix A 88 321
Source Pathway - Source Inputs
AERMOD
Line Volume Sources
Source Type: LINE VOLUME
Source: ROAD1 (HAUL ROUTE)
Release Height
[m]
Base Elevation
[m]
Y Coordinate for points
[m]
X Coordinate for Points
[m]
Length of Side
[m]
Emission Rate
[g/ s]
Building Height
[m]

16.00 3.53E-6 432330.87 3717336.79 160.70 3.40
432386.15 3717379.94 159.21 3.40
432481.89 3717428.48 154.23 3.40
432584.36 3717467.58 146.77 3.40
432704.36 3717487.80 138.62 3.40
432967.29 3717539.04 128.16 3.40
433081.90 3717566.01 119.10 3.40
433192.46 3717571.40 110.31 3.40
433243.70 3717561.96 106.64 3.40
Appendix A 89 322
Source Pathway - Source Inputs
AERMOD
Volume Sources Generated from Line Sources
Line
Source
ID
Volume
Source
ID
X Coordinate
[m]
Y Coordinate
[m]
Base
Elevation
[m]
Release
Height
[m[
Emission
Rate
[g/s]
Length of
Side
[m]
Building
Height
[m]
Initial Lateral
Dimencion
[m]
Initial Vertical
Dimencion
[m]
ROAD1 L0000001 432337.18 3717341.71 160.55 3.40 5.88E-8 16.00 7.44 3.16 L0000002 432349.79 3717351.56 160.22 3.40 5.88E-8 16.00 7.44 3.16 L0000003 432362.40 3717361.40 159.85 3.40 5.88E-8 16.00 7.44 3.16 L0000004 432375.02 3717371.25 159.45 3.40 5.88E-8 16.00 7.44 3.16 L0000005 432387.82 3717380.78 159.12 3.40 5.88E-8 16.00 7.44 3.16 L0000006 432402.10 3717388.02 158.60 3.40 5.88E-8 16.00 7.44 3.16 L0000007 432416.37 3717395.26 157.90 3.40 5.88E-8 16.00 7.44 3.16 L0000008 432430.64 3717402.49 157.18 3.40 5.88E-8 16.00 7.44 3.16 L0000009 432444.91 3717409.73 156.43 3.40 5.88E-8 16.00 7.44 3.16 L0000010 432459.18 3717416.96 155.65 3.40 5.88E-8 16.00 7.44 3.16 L0000011 432473.45 3717424.20 154.81 3.40 5.88E-8 16.00 7.44 3.16 L0000012 432487.99 3717430.81 153.91 3.40 5.88E-8 16.00 7.44 3.16 L0000013 432502.94 3717436.51 152.94 3.40 5.88E-8 16.00 7.44 3.16 L0000014 432517.89 3717442.22 151.90 3.40 5.88E-8 16.00 7.44 3.16 L0000015 432532.84 3717447.92 150.81 3.40 5.88E-8 16.00 7.44 3.16 L0000016 432547.79 3717453.63 149.67 3.40 5.88E-8 16.00 7.44 3.16 L0000017 432562.74 3717459.33 148.48 3.40 5.88E-8 16.00 7.44 3.16 L0000018 432577.69 3717465.03 147.20 3.40 5.88E-8 16.00 7.44 3.16 L0000019 432593.09 3717469.05 145.93 3.40 5.88E-8 16.00 7.44 3.16 L0000020 432608.87 3717471.71 144.70 3.40 5.88E-8 16.00 7.44 3.16 L0000021 432624.65 3717474.37 143.45 3.40 5.88E-8 16.00 7.44 3.16 L0000022 432640.43 3717477.03 142.31 3.40 5.88E-8 16.00 7.44 3.16 L0000023 432656.20 3717479.69 141.29 3.40 5.88E-8 16.00 7.44 3.16 L0000024 432671.98 3717482.35 140.34 3.40 5.88E-8 16.00 7.44 3.16 Appendix A 90 323
Source Pathway - Source Inputs
AERMOD
Line
Source
ID
Volume
Source
ID
X Coordinate
[m]
Y Coordinate
[m]
Base
Elevation
[m]
Release
Height
[m[
Emission
Rate
[g/s]
Length of
Side
[m]
Building
Height
[m]
Initial Lateral
Dimencion
[m]
Initial Vertical
Dimencion
[m]
ROAD1 L0000025 432687.76 3717485.01 139.42 3.40 5.88E-8 16.00 7.44 3.16 L0000026 432703.54 3717487.67 138.62 3.40 5.88E-8 16.00 7.44 3.16 L0000027 432719.25 3717490.70 137.89 3.40 5.88E-8 16.00 7.44 3.16 L0000028 432734.95 3717493.77 137.25 3.40 5.88E-8 16.00 7.44 3.16 L0000029 432750.65 3717496.83 136.71 3.40 5.88E-8 16.00 7.44 3.16 L0000030 432766.36 3717499.89 136.26 3.40 5.88E-8 16.00 7.44 3.16 L0000031 432782.06 3717502.95 135.90 3.40 5.88E-8 16.00 7.44 3.16 L0000032 432797.77 3717506.01 135.55 3.40 5.88E-8 16.00 7.44 3.16 L0000033 432813.47 3717509.07 135.18 3.40 5.88E-8 16.00 7.44 3.16 L0000034 432829.18 3717512.13 134.74 3.40 5.88E-8 16.00 7.44 3.16 L0000035 432844.88 3717515.19 134.21 3.40 5.88E-8 16.00 7.44 3.16 L0000036 432860.59 3717518.25 133.63 3.40 5.88E-8 16.00 7.44 3.16 L0000037 432876.29 3717521.31 133.00 3.40 5.88E-8 16.00 7.44 3.16 L0000038 432892.00 3717524.37 132.28 3.40 5.88E-8 16.00 7.44 3.16 L0000039 432907.70 3717527.43 131.53 3.40 5.88E-8 16.00 7.44 3.16 L0000040 432923.40 3717530.49 130.75 3.40 5.88E-8 16.00 7.44 3.16 L0000041 432939.11 3717533.55 129.83 3.40 5.88E-8 16.00 7.44 3.16 L0000042 432954.81 3717536.61 128.86 3.40 5.88E-8 16.00 7.44 3.16 L0000043 432970.49 3717539.80 127.86 3.40 5.88E-8 16.00 7.44 3.16 L0000044 432986.07 3717543.46 126.78 3.40 5.88E-8 16.00 7.44 3.16 L0000045 433001.64 3717547.12 125.60 3.40 5.88E-8 16.00 7.44 3.16 L0000046 433017.22 3717550.79 124.43 3.40 5.88E-8 16.00 7.44 3.16 L0000047 433032.79 3717554.45 123.20 3.40 5.88E-8 16.00 7.44 3.16 L0000048 433048.37 3717558.12 121.95 3.40 5.88E-8 16.00 7.44 3.16 L0000049 433063.94 3717561.78 120.68 3.40 5.88E-8 16.00 7.44 3.16 Appendix A 91 324
Source Pathway - Source Inputs
AERMOD
Line
Source
ID
Volume
Source
ID
X Coordinate
[m]
Y Coordinate
[m]
Base
Elevation
[m]
Release
Height
[m[
Emission
Rate
[g/s]
Length of
Side
[m]
Building
Height
[m]
Initial Lateral
Dimencion
[m]
Initial Vertical
Dimencion
[m]
ROAD1 L0000050 433079.51 3717565.45 119.49 3.40 5.88E-8 16.00 7.44 3.16 L0000051 433095.43 3717566.67 118.18 3.40 5.88E-8 16.00 7.44 3.16 L0000052 433111.41 3717567.45 116.89 3.40 5.88E-8 16.00 7.44 3.16 L0000053 433127.40 3717568.23 115.60 3.40 5.88E-8 16.00 7.44 3.16 L0000054 433143.38 3717569.01 114.33 3.40 5.88E-8 16.00 7.44 3.16 L0000055 433159.36 3717569.79 113.06 3.40 5.88E-8 16.00 7.44 3.16 L0000056 433175.34 3717570.57 111.81 3.40 5.88E-8 16.00 7.44 3.16 L0000057 433191.32 3717571.35 110.59 3.40 5.88E-8 16.00 7.44 3.16 L0000058 433207.07 3717568.71 109.38 3.40 5.88E-8 16.00 7.44 3.16 L0000059 433222.81 3717565.81 108.19 3.40 5.88E-8 16.00 7.44 3.16 L0000060 433238.54 3717562.91 107.03 3.40 5.88E-8 16.00 7.44 3.16 Appendix A 92 325
Source Pathway
AERMOD
Option not in use
Building Downwash Information
Emission Rate Units for Output
For Concentration
Concentration Unit Label:

Emission Unit Label:

Unit Factor: 1E6

GRAMS/SEC
MICROGRAMS/M**3
Source Group ID: DPM List of Sources in Group (Source Range or Single Sources) SITE
ROAD1
Source Groups
Variable Emissions
Appendix A 93 326
Source Pathway
AERMOD
Hour-of-Day / Day-of-Week Emission Rate Variation
Scenario: Scenario 1
Source ID: SITE
Weekdays
Hour 1 - 6 0.00 0.00 0.00 0.00 0.00 0.00
of 7 - 12 0.00 0.00 1.00 1.00 1.00 1.00
Day 13 - 18 0.00 1.00 1.00 1.00 1.00 0.00
19 - 24 0.00 0.00 0.00 0.00 0.00 0.00
Saturday
Hour 1 - 6 0.00 0.00 0.00 0.00 0.00 0.00
of 7 - 12 0.00 0.00 0.00 0.00 0.00 0.00
Day 13 - 18 0.00 0.00 0.00 0.00 0.00 0.00
19 - 24 0.00 0.00 0.00 0.00 0.00 0.00
Sunday
Hour 1 - 6 0.00 0.00 0.00 0.00 0.00 0.00
of 7 - 12 0.00 0.00 0.00 0.00 0.00 0.00
Day 13 - 18 0.00 0.00 0.00 0.00 0.00 0.00
19 - 24 0.00 0.00 0.00 0.00 0.00 0.00
Source ID: ROAD1
Weekdays
Hour 1 - 6 0.00 0.00 0.00 0.00 0.00 0.00
of 7 - 12 0.00 0.00 1.00 1.00 1.00 1.00
Day 13 - 18 0.00 1.00 1.00 1.00 1.00 0.00
19 - 24 0.00 0.00 0.00 0.00 0.00 0.00
Saturday
Hour 1 - 6 0.00 0.00 0.00 0.00 0.00 0.00
of 7 - 12 0.00 0.00 0.00 0.00 0.00 0.00
Day 13 - 18 0.00 0.00 0.00 0.00 0.00 0.00
19 - 24 0.00 0.00 0.00 0.00 0.00 0.00
Sunday
Hour 1 - 6 0.00 0.00 0.00 0.00 0.00 0.00
of 7 - 12 0.00 0.00 0.00 0.00 0.00 0.00
Day 13 - 18 0.00 0.00 0.00 0.00 0.00 0.00
19 - 24 0.00 0.00 0.00 0.00 0.00 0.00
Appendix A 94 327
Receptor Pathway
AERMOD
Receptor Networks
Note: Terrain Elavations and Flagpole Heights for Network Grids are in Page RE2 - 1 (If applicable) Generated Discrete Receptors for Multi-Tier (Risk) Grid and Receptor Locations for Fenceline Grid are in Page RE3 - 1 (If applicable) Discrete Receptors
Discrete Cartesian Receptors
X-Coordinate [m] Y-Coordinate [m] Terrain Elevations
Flagpole Heights [m]
(Optional)
Record
Number
Group Name
(Optional)
1 433064.66 3717636.96 RES 136.27
2 432739.31 3717670.08 RES 141.13
3 432739.31 3717657.42 RES 140.71
4 432739.31 3717644.75 RES 140.22
5 432741.26 3717624.30 RES 139.47
6 432751.98 3717608.71 RES 138.80
7 432755.87 3717591.18 RES 138.17
8 432773.41 3717581.44 RES 137.35
9 432783.15 3717572.67 NEAR-RES 136.89
10 432795.81 3717564.88 NEAR-RES 136.51
11 432838.67 3717560.01 NEAR-RES 136.43
12 432852.31 3717562.93 NEAR-RES 136.59
13 432867.89 3717563.90 NEAR-RES 136.82
14 432884.45 3717564.88 NEAR-RES 137.02
15 432897.12 3717568.77 NEAR-RES 137.12
16 432922.44 3717596.05 RES 137.57
17 432917.57 3717612.61 RES 137.76
18 432912.70 3717627.22 RES 137.95
19 432911.73 3717639.88 RES 138.14
20 432914.65 3717655.47 RES 138.39
21 432902.96 3717668.13 RES 138.48
22 432891.27 3717685.67 RES 138.77
23 432876.66 3717693.46 RES 139.05
24 432864.97 3717704.17 RES 139.42
25 432848.41 3717710.99 RES 139.75
26 432833.80 3717714.89 RES 140.01
27 432823.08 3717718.79 RES 140.23
28 432806.53 3717719.76 RES 140.49
29 432793.86 3717718.79 RES 140.83
30 432776.33 3717718.79 RES 141.18
Appendix A 95 328
Receptor Pathway
AERMOD
31 432783.15 3717670.08 RES 141.06
32 432795.81 3717673.98 RES 140.93
33 432811.40 3717673.98 RES 140.54
34 432837.70 3717666.18 RES 139.72
35 432847.44 3717651.57 RES 139.26
36 432859.13 3717636.96 RES 138.59
37 432863.02 3717621.38 RES 138.07
38 432864.97 3717601.89 RES 137.40
39 432831.85 3717608.71 RES 136.73
40 432812.37 3717615.53 RES 137.42
41 432799.71 3717624.30 RES 138.43
42 432788.02 3717642.81 RES 139.89
43 432860.10 3717380.77 OFFICE 133.68
44 432860.10 3717356.42 OFFICE 133.55
45 432851.33 3717296.03 OFFICE 133.24
46 432855.23 3717280.44 OFFICE 133.33
47 432856.20 3717245.37 OFFICE 133.85
48 432853.28 3717225.89 OFFICE 133.89
49 432844.52 3717175.24 OFFICE 134.18
50 432836.72 3717146.99 OFFICE 134.21
51 432751.00 3717323.30 COMM 136.79
52 432723.73 3717319.41 COMM 136.77
53 432702.30 3717314.54 COMM 136.87
54 432754.90 3717292.13 COMM 136.56
55 432763.67 3717266.80 COMM 136.64
56 432765.61 3717241.48 COMM 136.47
57 432765.61 3717213.23 COMM 136.51
58 432719.83 3717262.91 COMM 136.88
59 432718.86 3717241.48 COMM 136.93
60 432688.66 3717258.04 COMM 137.07
61 432669.18 3717258.04 COMM 137.05
62 432649.70 3717299.92 COMM 137.18
63 432675.02 3717307.72 COMM 137.19
64 432567.87 3717271.68 COMM 139.31
65 432574.69 3717252.19 COMM 139.38
66 432555.21 3717240.50 COMM 139.43
67 432566.90 3717216.15 COMM 139.23
68 432586.38 3717225.89 COMM 139.17
Appendix A 96 329
Receptor Pathway
AERMOD
69 432599.04 3717164.52 COMM 138.54
70 432617.55 3717175.24 COMM 138.07
71 432689.63 3717159.65 COMM 137.00
72 432677.94 3717130.43 COMM 136.96
73 432748.08 3717138.22 COMM 137.29
74 432740.29 3717118.74 COMM 137.28
75 432530.86 3717371.03 COMM 140.19
76 432543.52 3717345.71 COMM 140.47
77 432541.57 3717326.22 COMM 140.67
78 432528.91 3717308.69 COMM 140.40
79 432605.86 3717404.15 COMM 138.88
80 432581.51 3717396.36 COMM 138.78
81 432590.28 3717372.98 COMM 138.78
82 432611.71 3717380.77 COMM 138.77
83 432673.07 3717441.17 COMM 138.29
84 432648.72 3717434.35 COMM 138.21
85 432668.20 3717409.02 COMM 138.33
86 432965.30 3717204.46 NEAR-RES 119.56
87 433012.06 3717205.44 RES 118.77
88 433058.82 3717211.28 RES 118.60
89 433104.60 3717211.28 RES 118.50
90 433045.18 3717163.55 RES 118.80
91 433016.93 3717157.71 RES 118.94
92 432995.50 3717130.43 RES 119.28
93 432967.25 3717140.17 RES 119.33
94 432963.35 3717093.42 RES 120.15
95 432982.84 3717097.31 RES 120.07
96 432960.43 3717067.12 RES 120.08
97 432976.99 3717069.06 RES 120.04
98 432960.43 3717036.92 RES 119.70
99 432983.81 3717035.94 RES 119.72
100 433010.11 3717055.43 RES 119.22
101 433026.67 3717122.64 RES 118.98
102 433045.18 3717091.47 RES 118.96
103 432651.64 3717505.46 NEAR-RES 141.28
104 432630.21 3717505.46 RES 141.44
105 432605.86 3717504.48 RES 141.70
106 432580.53 3717503.51 RES 141.90
Appendix A 97 330
Receptor Pathway
AERMOD
107 432559.10 3717499.61 RES 142.20
108 432537.67 3717495.72 RES 142.38
109 432507.48 3717517.15 RES 142.81
110 432508.45 3717501.56 RES 142.70
111 432531.83 3717515.20 RES 142.38
112 432547.42 3717518.12 RES 142.31
113 432586.38 3717523.97 RES 141.86
114 432607.81 3717524.94 RES 141.76
115 432630.21 3717553.19 RES 141.38
116 432628.27 3717535.66 RES 141.52
117 432651.64 3717556.11 RES 141.17
118 432649.70 3717534.68 RES 141.22
119 432632.16 3717579.49 RES 141.44
120 432649.70 3717579.49 RES 141.34
121 432627.29 3717599.95 RES 141.65
122 432649.70 3717601.89 RES 141.49
123 432631.19 3717619.43 RES 141.82
124 432640.93 3717620.40 RES 141.76
125 432626.32 3717639.88 RES 142.42
126 432646.77 3717640.86 RES 142.25
127 432626.32 3717665.21 RES 142.47
128 432646.77 3717666.18 RES 142.30
129 433017.90 3717513.25 NEAR-RES 130.76
130 433019.85 3717493.77 NEAR-RES 131.35
131 433019.85 3717478.18 NEAR-RES 131.55
132 433020.83 3717464.55 NEAR-RES 131.69
133 433023.75 3717449.93 NEAR-RES 131.79
134 433025.70 3717437.27 NEAR-RES 131.92
135 433022.77 3717419.74 NEAR-RES 132.06
136 433027.65 3717404.15 NEAR-RES 132.20
137 433036.41 3717389.54 NEAR-RES 132.36
138 433064.66 3717396.36 RES 132.15
139 433073.43 3717408.05 RES 132.08
140 433080.25 3717428.50 RES 132.02
141 433072.45 3717439.22 RES 131.90
142 433062.71 3717455.78 RES 131.76
143 433060.76 3717468.44 RES 131.59
144 433057.84 3717485.00 RES 131.31
Appendix A 98 331
Receptor Pathway
AERMOD
145 433061.74 3717499.61 RES 131.18
146 433099.73 3717507.41 RES 125.42
147 433101.68 3717491.82 RES 125.49
148 433102.65 3717477.21 RES 125.56
149 433102.65 3717460.65 RES 125.73
150 433140.64 3717507.41 RES 125.20
151 433140.64 3717494.74 RES 125.38
152 433140.64 3717476.24 RES 125.56
153 433139.67 3717460.65 RES 125.68
154 433143.56 3717446.04 RES 125.82
155 433139.67 3717432.40 RES 125.80
156 433137.72 3717413.89 RES 125.69
157 433134.80 3717396.36 RES 125.54
158 433128.95 3717381.75 RES 125.43
159 433123.11 3717372.01 RES 125.32
160 433178.63 3717386.62 RES 117.71
161 433181.55 3717403.18 RES 118.00
162 433182.53 3717418.76 RES 118.19
163 433181.55 3717434.35 RES 118.44
164 433182.53 3717450.91 RES 118.56
165 433182.53 3717467.47 RES 118.61
166 433179.60 3717479.16 RES 118.90
167 433178.63 3717494.74 RES 119.09
168 433179.60 3717508.38 RES 119.17
169 433222.46 3717497.67 RES 118.85
170 433221.49 3717483.05 RES 118.76
171 433220.52 3717468.44 RES 118.64
172 433219.54 3717455.78 RES 118.46
173 433219.54 3717437.27 RES 118.22
174 433219.54 3717419.74 RES 118.07
175 433219.54 3717403.18 RES 117.96
176 433219.54 3717392.46 RES 117.94
177 433213.70 3717373.96 RES 117.73
178 433211.75 3717356.42 RES 117.51
179 433201.03 3717345.71 RES 117.41
180 433149.41 3717218.10 RES 114.94
181 433153.30 3717202.51 RES 114.97
182 433154.28 3717185.95 RES 115.02
Appendix A 99 332
Receptor Pathway
AERMOD
183 433131.87 3717283.36 POS 116.58
184 433216.62 3717292.13 RES 110.56
185 433202.98 3717683.72 RES 127.17
186 433192.27 3717670.08 RES 127.12
187 433187.40 3717657.42 RES 127.15
188 433168.89 3717636.96 RES 127.24
189 433164.99 3717631.12 RES 127.26
190 433138.69 3717623.32 RES 127.54
191 433113.37 3717616.51 RES 127.54
192 433126.03 3717653.52 RES 127.43
193 433129.93 3717675.93 RES 127.55
194 433148.43 3717689.56 RES 127.29
195 433165.97 3717699.30 RES 127.13
196 433182.53 3717710.99 RES 126.99
197 433004.27 3717603.84 RES 136.04
198 433034.46 3717615.53 RES 136.17
199 433059.79 3717624.30 RES 136.26
200 433070.51 3717648.65 RES 136.44
201 433077.32 3717667.16 RES 136.48
202 433086.09 3717684.69 RES 136.51
203 433036.41 3717662.29 RES 136.26
204 433025.70 3717644.75 RES 136.15
205 432992.58 3717651.57 RES 135.99
206 432993.55 3717634.04 RES 136.10
207 432996.47 3717699.30 RES 136.25
208 433007.19 3717698.33 RES 136.25
209 433035.44 3717694.43 RES 136.43
210 433052.00 3717691.51 RES 136.51
211 433046.15 3717735.35 RES 144.59
212 433064.66 3717738.27 RES 144.61
213 433106.55 3717739.24 RES 144.48
214 433140.64 3717763.59 RES 144.13
215 433015.96 3717745.09 RES 144.23
216 433001.34 3717746.06 RES 144.25
217 433013.03 3717772.36 RES 144.09
218 433000.37 3717787.95 RES 143.86
219 433070.51 3717767.49 RES 144.64
220 433089.99 3717766.52 RES 144.61
Appendix A 100 333
Receptor Pathway
AERMOD
221 433115.31 3717778.21 RES 144.21
222 433082.19 3717791.84 RES 144.45
223 433085.12 3717812.30 RES 144.14
224 433018.88 3717830.81 RES 144.25
225 432420.78 3717653.52 RES 147.63
226 432412.02 3717635.01 RES 148.43
227 432403.25 3717614.56 RES 149.54
228 432399.35 3717597.02 RES 150.32
229 432392.53 3717581.44 RES 150.75
230 432401.30 3717561.96 RES 151.68
231 432405.20 3717539.55 RES 152.41
232 432417.86 3717525.91 RES 153.17
233 432426.63 3717511.30 RES 153.62
234 432442.21 3717493.77 RES 154.30
235 432454.88 3717478.18 RES 154.87
236 432463.64 3717462.60 RES 155.39
237 432419.81 3717443.12 RES 155.37
238 432374.03 3717665.21 RES 147.96
239 432351.62 3717618.45 RES 149.81
240 432353.57 3717541.50 RES 151.94
241 432374.03 3717496.69 RES 153.23
242 432397.40 3717469.42 RES 154.27
243 432434.42 3717745.09 RES 149.10
244 432423.71 3717692.48 RES 147.87
245 432478.25 3717775.28 RES 146.19
246 432483.13 3717728.53 RES 145.63
247 432482.15 3717689.56 RES 145.15
248 432525.01 3717764.57 RES 145.66
249 432527.93 3717725.60 RES 145.22
250 432529.88 3717693.46 RES 144.71
251 432466.57 3717650.60 RES 144.70
252 432491.89 3717655.47 RES 144.61
253 432458.77 3717628.19 RES 144.65
254 432493.84 3717631.12 RES 144.36
255 432454.88 3717608.71 RES 144.27
256 432496.76 3717608.71 RES 143.87
257 432481.18 3717585.33 RES 143.90
258 432485.07 3717561.96 RES 144.14
Appendix A 101 334
Receptor Pathway
AERMOD
259 432485.07 3717544.42 RES 144.04
260 432447.08 3717576.57 RES 144.34
261 432541.57 3717653.52 RES 143.81
262 432544.49 3717630.14 RES 143.67
263 432581.51 3717636.96 RES 142.55
264 432594.17 3717599.95 RES 142.11
265 432571.77 3717598.00 RES 142.30
266 432535.73 3717612.61 RES 143.25
267 432550.34 3717574.62 RES 142.66
268 432532.80 3717567.80 RES 142.82
269 433296.50 3717761.65 RES 125.93
270 432563.00 3717816.20 RES 146.67
271 432524.04 3717806.45 RES 146.51
272 432604.89 3717823.01 RES 146.01
273 432641.90 3717826.91 RES 145.99
274 432691.58 3717861.98 RES 146.69
275 432694.50 3717803.53 RES 145.15
276 432695.48 3717757.75 RES 143.96
277 432698.40 3717711.97 RES 142.76
278 432640.93 3717763.59 RES 144.60
279 432642.88 3717708.07 RES 143.08
280 432611.71 3717762.62 RES 144.72
281 432603.91 3717710.02 RES 143.19
282 432559.10 3717758.72 RES 145.64
283 432564.95 3717702.23 RES 144.81
284 432731.52 3717806.45 RES 145.17
285 432731.52 3717757.75 RES 143.91
286 432731.52 3717707.10 RES 142.53
287 432730.55 3717861.98 RES 146.58
288 432776.33 3717861.98 RES 145.97
289 432778.28 3717808.40 RES 144.47
290 432778.28 3717764.57 RES 143.22
291 432832.83 3717862.95 POS 142.56
292 432875.69 3717861.98 POS 145.65
293 432923.42 3717864.90 POS 150.03
294 432825.03 3717810.35 POS 141.35
295 432876.66 3717810.35 POS 142.93
296 432921.47 3717806.45 POS 146.21
Appendix A 102 335
Receptor Pathway
AERMOD
297 432831.85 3717767.49 POS 140.42
298 432880.56 3717768.46 POS 142.69
299 432916.60 3717748.98 POS 143.48
300 432982.84 3717351.55 POS 118.23
301 432961.41 3717332.07 POS 117.83
302 432931.21 3717297.98 POS 117.79
303 433022.77 3717307.72 POS 117.89
304 432999.40 3717286.29 POS 117.26
305 432961.41 3717255.12 POS 117.63
306 433055.89 3717282.39 POS 117.48
307 433024.72 3717256.09 POS 116.75
308 433004.27 3717237.58 POS 116.91
309 433068.56 3717245.37 POS 116.23
310 433197.14 3717276.55 POS 111.70
311 433176.68 3717247.32 POS 113.65
312 433173.76 3717310.64 POS 116.08
313 433143.56 3717336.94 POS 117.58
314 433099.73 3717359.34 POS 122.99
315 432374.03 3717318.43 COMM 160.15
316 432400.33 3717259.01 COMM 159.39
317 432425.65 3717231.74 COMM 159.09
318 432967.25 3717407.07 INDUST 126.01
319 432782.17 3717036.92 POS 142.12
320 432832.83 3717007.70 POS 137.28
321 432691.58 3717064.19 POS 137.94
322 432383.77 3717207.38 POS 159.87
323 432475.33 3717145.04 POS 160.91
324 432651.64 3717085.62 POS 138.12
325 433823.13 3716702.40 POS 88.14
326 432709.08 3717636.99 POS 140.33
Plant Boundary Receptors
Appendix A 103 336
Receptor Pathway
AERMOD
Receptor Groups
Group ID Group Description
Record
Number
1 COMM Non-Residential Commerical
2 OFFICE Non-Residential Office
3 POS Non-Residential Park - Open Space
4 RES Residential
5 INDUST Non-Residential -Industrial
6 NEAR-RES Residential
Appendix A 104 337
Meteorology Pathway
AERMOD
Met Input Data
Surface Met Data
Profile Met Data
Met\MSVJ_V11_trimmed.sfc
Default AERMET format
Filename:

Format Type:

Filename:

Format Type:

Met\MSVJ_V11_trimmed.PFL
Potential Temperature Profile
Base Elevation above MSL (for Primary Met Tower): 168.00 [m] Wind Direction
Rotation Adjustment [deg]:

Meteorological Station Data
Upper Air
On-Site
Station No. Year Station Name
Surface
Stations X Coordinate [m] Y Coordinate [m]
2017
2017
2017
Default AERMET format
Wind Speed
Wind Speeds are Vector Mean (Not Scalar Means)
Data Period
Start Date: 1/1/2017 Start Hour: 1 End Date: 12/31/2021 End Hour: 24 Data Period to Process

10.8 8.23

5.14 3.09

1.54 No Upper Bound
Wind Speed [m/s] Stability Category Wind Speed [m/s]
F
E
D
C
B
A
Stability Category
Wind Speed Categories
Appendix A 105 338
Output Pathway
AERMOD
Appendix A 106 339
Results Summary
Argonaut Residential Project
Construction HRA - DPM
PM10 - Concentration - Source Group: DPM
Averaging
Period Rank Peak
X
(m)
Y
(m)
ZELEV
(m)
ZHILL
(m)
Peak Date,
Start Hour
ZFLAG
(m) Units
PERIOD 0.06186 ug/m^3 432860.10 3717380.77 133.68 0.00 133.68 Appendix A 107 340
Sensitive Receptor Summary
Argonaut Residential Project
Construction HRA - DPM
PM10 - Concentration - Source Group: DPM
Averaging
Period Rank Peak
X
(m)
Y
(m)
ZELEV
(m)
ZHILL
(m)
Peak Date,
Start Hour
ZFLAG
(m) Units
Receptor
ID
PERIOD 0.02399 ug/m^3 432783.15 3717572.67 136.89 0.00 136.89 PERIOD 0.03067 ug/m^3 432795.81 3717564.88 136.51 0.00 136.51 PERIOD 0.03893 ug/m^3 MEIR 432838.67 3717560.01 136.43 0.00 136.43 PERIOD 0.03582 ug/m^3 432852.31 3717562.93 136.59 0.00 136.59 PERIOD 0.03246 ug/m^3 432867.89 3717563.90 136.82 0.00 136.82 PERIOD 0.02807 ug/m^3 432884.45 3717564.88 137.02 0.00 137.02 PERIOD 0.02390 ug/m^3 432897.12 3717568.77 137.12 0.00 137.12 Appendix A 108 341

HEALTH RISK ASSESSMENT CALCULATIONS
Argonaut Residential Project
The Health Risk Assessment (HRA) follows South Coast Air Quality Management District (SCAQMD) Risk Assessment Guidelines and is based on foundational Office of Environmental Health Hazard Assessment (OEHHA) Guidance1. This risk assessment intake methodology addresses children’s greater sensitivity and health impacts from early exposure to carcinogenic compounds. The chemical intake or dose describing the frequency and duration of the exposure is estimated using receptor’s breathing rates, exposure duration, and exposure frequency. The calculations include the use of age-specific weighting factors, breathing rates, fraction of time at home, and reduced exposure durations.

The HRA was conducted utilizing the California Air Resources Board’s (ARB’s) Hot Spots Analysis and Reporting Program Version 2 (HARP2) to automatically calculate risks for the projects using OEHHA promulgated cancer potency and reference exposure levels. The approach used in HARP is consistent with SCAQMD’s risk assessment guidance methodology under permitting rules 1401 and 212.2 These factors are described below, followed by a summary of the HARP2 HRA inputs to determine risk from the maximally exposed individual resident and worker.

AERMOD Inputs — The AMS/EPA Regulatory Model (AERMOD) was utilized to predict the ground level concentrations resulting from the emissions of Diesel Particulate Matter (DPM) (represented as PM10 exhaust) associated with construction activities. The modeling included both emissions generated at the project site and those generated along the anticipated haul roads within approximately 1,000 ft of the site boundary. Diesel exhaust from material movement were characterized by an area source with a height of 5 meters to account for the height of the construction exhaust from the off-road equipment.

Roadway emissions were modeled as line-volume sources or adjacent volume sources using US EPA Haul Road Guidance. The modeling utilized Urban dispersion coefficients and SCAQMD-provided meteorological data from the Mission Viejo meteorological station (MSVJ). Emissions were modeled only during the hours of 8 AM – 5 PM (with a one-hour break for lunch) Monday to Friday. DPM Emissions were calculated using CalEEMod using emissions from PM10 exhaust from diesel vehicles and off-road construction equipment exhaust.

Age Sensitivity Factors — Studies have shown that young animals are more sensitive than adult animals to exposure to many carcinogens.3
Therefore, OEHHA developed age sensitivity factors (ASFs) to account for the increased sensitivity to carcinogens during early-in-life exposures. Accordingly, the cancer risk methodology applies different ASFs by age groups. The ASFs utilized a 10-fold multiplier in sensitivity for 1 Office of Environmental Health Hazard Assessment (OEHHA). 2015. The Air Toxics Hot Spots Program Guidance Manual for Preparation of Health Risk Assessments. Website: https://oehha.ca.gov/media/downloads/crnr/2015guidancemanual.pdf. Accessed December 24, 2024. 2 South Coast Air Quality Management District (SCAQMD). 2017. Risk Assessment Procedures for Rules 1401, 1401.1 and 212 Version 8.1.

September. Website: https://www.aqmd.gov/docs/default-source/permitting/rule-1401-risk-assessment/riskassessproc-v8-1.pdf.

Accessed December 24, 2024.
3 Office of Environmental Health Hazard Assessment (OEHHA). 2009. Technical Support Document for Cancer Potency Factors 2009. June.

Website: http://www.oehha.ca.gov/air/hot_spots/tsd052909.html. Accessed December 24, 2024.

Appendix A 109 342
the third trimester and infants less than age 2, a 3-fold increase in sensitivity for children ages 2 to 16 years old, and a sensitivity factor of 1 for ages 16 and older.

Daily breathing rates (age-specific daily air intake) — Breathing rates are determined for specific age groups (i.e., third trimester, 0-2, 2-16, and 16-30 years). The analysis follows ARB’s Risk Management Policy (RMP) that includes recommendations for inhalation exposures. For residential exposures, SCAQMD procedures adopt ARB’s RMP policy which recommends using the high-end daily breathing rates (DBR) (e.g., 95th percentile) for children from the third trimester through age 2, and 80th percentile DBR for all other ages.4
Time at home – The time at home applies only applies to residential receptors. Residents are assumed to be at home 350 days per year, which assumes individuals are away for approximately 2 weeks of vacation. The fraction of time at home refers to the estimated amount of time residents stay at home during these 350 days. The HRA assumes 100 percent time at home for receptors under age 16. Since the duration of construction is only 1.53 years, all exposure is for infants/children less than 16 years of age.

Exposure Duration — OEHHA 2015 guidelines specify a 30-year residential exposure duration for estimating cancer risk at the maximum exposed individual resident (MEIR). This is based on studies showing that 30 years is a reasonable estimate of the 90th to 95th percentile of residency duration in the population. A 25-year standard exposure duration is the default to estimate cancer risk for off-site workers. However, risk assessors can use other exposure durations with proper justification and documentation. For example, short-term projects (e.g., construction projects) can now be evaluated for as short a duration as 6 months. Because there are no significant sources of TAC emissions during operations, the exposure assessment is limited to the duration of the proposed project construction 399 workdays or 1.53 years.

Residential Cancer Risk — Cancer risk for individual resident receptors exposed to DPM were calculated utilizing HARP2. Consistent with OEHHA guidance, the start of residential exposure was assumed to occur in the third trimester (-0.25 years) to accommodate the increased susceptibility of exposures in early life. Inhalation is the only exposure pathway included in the OEHHA risk assessment guidelines for Diesel Exhaust. The exposure assessment was modeled for Inhalation pathway only, using Risk Management Program.

Exposure Duration Bin Distribution:
3rd Trimester Bin: 0.25
0<2 Years Bin: 1.28
2<9 Years Bin: 0
2<16 Years Bin: 0
16<30 Years Bin: 0
4 California Air Resources Board (ARB) and California Air Pollution Control Officers Association. 2015. Risk Management Guidance for Stationary Sources of Air Toxics. July 23. Website: https://ww2.arb.ca.gov/sites/default/files/classic/toxics/rma/rmgssat.pdf. Accessed December 24, 2024.

Appendix A 110 343
16 to 70 Years Bin: 0
Worker Cancer Risk — Cancer risk for off-site worker receptors exposed to DPM were calculated utilizing HARP2. Consistent with OEHHA guidance, the start of residential exposure was assumed to start at age 16 and occur over the construction period of 1.53 years. Inhalation is the only exposure pathway included in the OEHHA risk assessment guidelines for Diesel Exhaust. The exposure assessment was modeled for Inhalation pathway only, using Risk Management Program assuming the 80th percentile breathing rate for adults. All exposure is in the adult age bin (16 <30 years), with no adjustments for age sensitivity.

The worker adjustment factor (WAF) is used to determine the long-term concentration the worker is breathing during their work shift. Therefore, the long-term concentration is adjusted so it is based only on the hours when the worker is present. For this project, assuming the emitting source and worker’s schedules are the same, the adjustment factor is 4.2 = (24 hours per day/8 hours per shift) x (7 days in a week/5 days in a work week).

HARP2 provides for the specification of the WAF for worker cancer risk assessments, and this was entered as 4.2 to make this adjustment.

Noncancer Chronic Health Risks
Chronic RELs are used to assess residential health impacts characterized by the chronic hazard index, affecting the respiratory system for DPM.

Potential chronic noncancer health impacts use the long-term annual average concentration regardless of the emitting facility’s schedule.

Appendix A 111 344
HARP2 - HRACalc (dated 22118) 1/1/2025 3:06:32 AM - Output Log GLCs loaded successfully
Pollutants loaded successfully
**********************************

RISK SCENARIO SETTINGS
Receptor Type: Resident
Scenario: Cancer
Calculation Method: HighEnd
**********************************

EXPOSURE DURATION PARAMETERS FOR CANCER
Start Age: -0.25
Total Exposure Duration: 1.28
Exposure Duration Bin Distribution
3rd Trimester Bin: 0.25
0<2 Years Bin: 1.28
2<9 Years Bin: 0
2<16 Years Bin: 0
16<30 Years Bin: 0
16 to 70 Years Bin: 0
**********************************

PATHWAYS ENABLED
NOTE: Inhalation is always enabled and used for all assessments. The remaining pathways are only used for cancer and noncancer chronic assessments.

Inhalation: True
Soil: False
Dermal: False
Mother's milk: False
Water: False
Fish: False
Homegrown crops: False
Beef: False
Dairy: False
Pig: False
Chicken: False
Egg: False
**********************************

INHALATION
Daily breathing rate: RMP
**Worker Adjustment Factors**
Worker adjustment factors enabled: NO
**Fraction at time at home**
3rd Trimester to 16 years: OFF
16 years to 70 years: OFF
**********************************
TIER 2 SETTINGS
Tier2 adjustments were used in this assessment. Please see the input file for details.

Tier2 - What was changed: ED or start age changed|
Calculating cancer risk
Cancer risk saved to: F:\Jobs\49400049\ConHRA\HARP2\ResCancerCancerRisk.csv HRA ran successfully
Appendix A 112 345
*HARP - HRACalc v22118 1/1/2025 3:06:32 AM -
Cancer Risk - Input File: F:\Jobs\49400049\ConHRA\HARP2\ResCancerHRAInput.hra UTME UTMN Pollutant Conc (ug/m3) Risk Scenario Inhalation Risk 432838.67 3717560.01 DieselExhPM 0.039 8.7296e-06 1.28YrCancerRMP_Inh 8.7296e-06 Appendix A 113 346
HARP2 - HRACalc (dated 22118) 1/16/2025 5:43:02 AM - Output Log GLCs loaded successfully
Pollutants loaded successfully
**********************************

RISK SCENARIO SETTINGS
Receptor Type: Resident
Scenario: NCChronic
Calculation Method: HighEnd
**********************************

EXPOSURE DURATION PARAMETERS FOR CANCER
**Exposure duration are only adjusted for cancer assessments** **********************************

PATHWAYS ENABLED
NOTE: Inhalation is always enabled and used for all assessments. The remaining pathways are only used for cancer and noncancer chronic assessments.

INHALATION
Daily breathing rate: RMP
**Worker Adjustment Factors**
Worker adjustment factors enabled: NO
**Fraction at time at home**
NOTE: Exposure duration (i.e., start age, end age, ED, & FAH) are only adjusted for cancer assessments. **********************************
TIER 2 SETTINGS
Tier2 adjustments were used in this assessment. Please see the input file for details.

Tier2 - What was changed: ED or start age changed|
Calculating chronic risk
Chronic risk saved to: F:\Jobs\49400049\ConHRA\HARP2\ResChronicNCChronicRisk.csv HRA ran successfully
Appendix A 114 347
*HARP - HRACalc v22118 1/16/2025 5:43:02 AM -
Chronic Risk - Input File: F:\Jobs\49400049\ConHRA\HARP2\ResChronicHRAInput.hra UTME UTMN Pollutant Conc (ug/m3) CV CNS IMMUN KIDNEY GILV REPRO RESP SKIN EYE B/T ENDO BLOOD ODOR GEN 432838.67 3717560.01 DieselExhPM 0.039 0.0 0.0 0.0 0.0 0.0 0.0 0.0078 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Appendix A 115 348
HARP2 - HRACalc (dated 22118) 1/1/2025 3:09:59 AM - Output Log GLCs loaded successfully
Pollutants loaded successfully
**********************************

RISK SCENARIO SETTINGS
Receptor Type: Worker
Scenario: Cancer
Calculation Method: Derived
**********************************

EXPOSURE DURATION PARAMETERS FOR CANCER
Start Age: 16
Total Exposure Duration: 1.53
Exposure Duration Bin Distribution
3rd Trimester Bin: 0
0<2 Years Bin: 0
2<9 Years Bin: 0
2<16 Years Bin: 0
16<30 Years Bin: 1.53
16 to 70 Years Bin: 0
**********************************

PATHWAYS ENABLED
NOTE: Inhalation is always enabled and used for all assessments. The remaining pathways are only used for cancer and noncancer chronic assessments.

INHALATION
Daily breathing rate: Moderate8HR
**Worker Adjustment Factors**
NOTE: The worker adjustment factors below are only used for cancer assessments. However, the GLC adjustment factor is also applied to 8-hr noncancer chronic assessments.

Worker adjustments factors enabled: YES
GLC adjustment factor: 4.2
Exposure frequency: 250
**Fraction at time at home**
3rd Trimester to 16 years: OFF
16 years to 70 years: OFF
**********************************
TIER 2 SETTINGS
Tier2 adjustments were used in this assessment. Please see the input file for details.

Tier2 - What was changed: ED or start age changed|
Calculating cancer risk
Cancer risk saved to: F:\Jobs\49400049\ConHRA\HARP2\WorkerCancerCancerRisk.csv HRA ran successfully
Appendix A 116 349
*HARP - HRACalc v22118 1/1/2025 3:09:59 AM -
Cancer Risk - Input File: F:\Jobs\49400049\ConHRA\HARP2\WorkerCancerHRAInput.hra UTME UTMN Pollutant Conc (ug/m3) Risk Scenario Inhalation Risk 432860.1 3717380.77 DieselExhPM 0.062 1.0292e-06 1.53YrCancerDerived_Inh 1.0292e-06 Appendix A 117 350
HARP2 - HRACalc (dated 22118) 1/16/2025 5:43:39 AM - Output Log GLCs loaded successfully
Pollutants loaded successfully
**********************************

RISK SCENARIO SETTINGS
Receptor Type: Worker
Scenario: NCChronic
Calculation Method: HighEnd
**********************************

EXPOSURE DURATION PARAMETERS FOR CANCER
**Exposure duration are only adjusted for cancer assessments** **********************************

PATHWAYS ENABLED
NOTE: Inhalation is always enabled and used for all assessments. The remaining pathways are only used for cancer and noncancer chronic assessments.

Worker adjustments factors enabled: YES
GLC adjustment factor: 4.2
Exposure frequency: 250
**Fraction at time at home**
NOTE: Exposure duration (i.e., start age, end age, ED, & FAH) are only adjusted for cancer assessments. **********************************
TIER 2 SETTINGS
Tier2 adjustments were used in this assessment. Please see the input file for details.

Tier2 - What was changed: ED or start age changed|
Calculating chronic risk
Chronic risk saved to: F:\Jobs\49400049\ConHRA\HARP2\WorkerChronicNCChronicRisk.csv HRA ran successfully
Appendix A 118 351
*HARP - HRACalc v22118 1/16/2025 5:43:39 AM -
Chronic Risk - Input File: F:\Jobs\49400049\ConHRA\HARP2\WorkerChronicHRAInput.hra UTME UTMN Pollutant Conc (ug/m3) CV CNS IMMUN KIDNEY GILV REPRO RESP SKIN EYE B/T ENDO BLOOD ODOR GEN 432860.1 3717380.77 DieselExhPM 0.062 0.0 0.0 0.0 0.0 0.0 0.0 0.0124 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Appendix A 119 352
Argonaut Residential 0.054 bhphr/gal
Construction Equipment - Unmitigated 18.5 gal/bhp-hr
Phase Name Equipment Type Fuel Type Engine Tier Number per Day Hours Per Day Horsepower Load Factor Days bhp-hr gallons Demolition Concrete/Industrial Saws Diesel Average 1 8 33 0.73 20 3854 208 Demolition Rubber Tired Dozers Diesel Average 1 8 367 0.4 20 23488 1268 Demolition Tractors/Loaders/Backhoes Diesel Average 3 8 84 0.37 20 14918 806 Site Preparation Graders Diesel Average 1 8 148 0.41 3 1456 79 Site Preparation Scrapers Diesel Average 1 8 423 0.48 3 4873 263 Site Preparation Tractors/Loaders/Backhoes Diesel Average 1 7 84 0.37 3 653 35 Grading Graders Diesel Average 1 8 148 0.41 6 2913 157
Grading Rubber Tired Dozers Diesel Average 1 8 367 0.4 6 7046 381 Grading Tractors/Loaders/Backhoes Diesel Average 2 7 84 0.37 6 2611 141 Building Construction Cranes Diesel Average 1 8 367 0.29 330 280975 15173 Building Construction Forklifts Diesel Average 2 7 82 0.2 330 75768 4091 Building Construction Generator Sets Diesel Average 1 4 14 0.74 330 13675 738 Building Construction Tractors/Loaders/Backhoes Diesel Average 1 6 84 0.37 330 61538 3323 Building Construction Welders Electric Average 3 8 46 0.45 330 0 0 Paving Cement and Mortar Mixers Diesel Average 1 8 10 0.56 20 896 48 Paving Pavers Diesel Average 1 8 81 0.42 20 5443 294
Paving Paving Equipment Diesel Average 1 8 89 0.36 20 5126 277 Paving Rollers Diesel Average 2 8 36 0.38 20 4378 236
Paving Tractors/Loaders/Backhoes Diesel Average 1 8 84 0.37 20 4973 269 Architectural Coating Air Compressors Electric Average 1 6 37 0.48 20 0 0 27,788
Appendix A 120 353
Argonaut Residential

5.3. Construction Vehicles

5.3.1 Unmitigated
Phase Name Trip Type One-Way Trips per Day Miles per Trip Days VMT Vehicle Mix Demolition
Demolition Worker 13 18.5 20 4625 LDA,LDT1,LDT2
Demolition Vendor 10.2 HHDT,MHDT
Demolition Hauling 81 20 20 32500 HHDT
Demolition Onsite truck HHDT
Site Preparation
Site Preparation Worker 8 18.5 3 416 LDA,LDT1,LDT2
Site Preparation Vendor 10.2 HHDT,MHDT
Site Preparation Hauling 0 20 3 0 HHDT
Site Preparation Onsite truck HHDT
Grading
Grading Worker 10 18.5 6 1110 LDA,LDT1,LDT2
Grading Vendor 10.2 HHDT,MHDT
Grading Hauling 50 20 6 6000 HHDT
Grading Onsite truck HHDT
Building Construction
Building Construction Worker 44 18.5 330 268132 LDA,LDT1,LDT2 Building Construction Vendor 7 10.2 330 21949 HHDT,MHDT Building Construction Hauling 0 20 330 0 HHDT
Building Construction Onsite truck HHDT
Paving
Paving Worker 15 18.5 20 5550 LDA,LDT1,LDT2
Paving Vendor 10.2 HHDT,MHDT
Paving Hauling 9 20 20 3600 HHDT
Paving Onsite truck HHDT
Architectural Coating
Architectural Coating Worker 9 18.5 20 3250 LDA,LDT1,LDT2 Architectural Coating Vendor 10.2 HHDT,MHDT
Architectural Coating Hauling 0 20 20 0 HHDT
Architectural Coating Onsite truck HHDT
(County-Specific Fuel Efficiency)
mpg gal/mile EMFAC Vehicle Category

30.69 0.033 LDA

25.63 0.039 LDT1

25.05 0.040 LDT2

8.98 0.111 MHDT

6.06 0.165 HHDT
Gasoline for Light Duty and Diesel for Heavy Duty - Consistent with CalEEMod Assumptions Orange County 2025

VMT TOTALS
Vehicle
Category Fuel Efficiency (MPG) Fuel (gallons)
283,083 LDA,LDT1,LDT2 26.75 10583
21,949 HHDT,MHDT 7.52 2919
- MHDT 8.98 0
42,100 HHDT 6.06 6947
20,449
Appendix A 121 354
Argonaut Residential

5.11. Operational Energy Consumption

5.11.1 Unmitigated
Land Use Electricity (kWh/yr) Natural Gas (kBTU/yr)
Condo/Townhouse 444090 0
Parking Lot 34724 0
478,814
Appendix A 122 355
Argonaut Residential
Energy Calculations - Operations Fuel Use from On-Road Mobile Sources Region Orange
OpYear 2027
Fuel Consumption by Vehicle Category - Annual Usage (gallons ; KWh-hr for Electicity) Fuel Usage HHDT LDA LDT1 LDT2 LHD1 LHD2 MCY MDV MH MHDT OBUS SBUS UBUS Gasoline 45,054 1 18643 1986 11703 1539 284 692 8703 631 736 83 43 11 Diesel 4,243 1073 31 0 36 628 326 0 101 166 1788 38 54 0 Natural Gas 378 136 0 0 0 0 0 0 0 0 20 6 107 109
Electricity 22,959 237 18796 97 1374 438 114 0 1455 0 415 9 20 5 EMFAC Default Mix- County Popuation VMT HHDT LDA LDT1 LDT2 LHDT1 LHDT2 MCY MDV MH MHDT OBUS SBUS UBUS Orange County Population 2,366,528 13,648 1,170,612 94,631 558,478 65,876 17,275 52,507 343,688 8,510 36,755 1,419 2,287 841 Vehicle Mix Default 1 0.6% 49.5% 4.0% 23.6% 2.8% 0.7% 2.2% 14.5% 0.4% 1.6% 0.1% 0.1% 0.0% Vehicle Types /Mix in CalEEMod VMT HHDT LDA LDT1 LDT2 LHDT1 LHDT2 MCY MDV MH MHDT OBUS SBUS UBUS Condo/Townhouse 1325753 1 1 1 1 1 1 1 1 1 1 1 1 1
Vehicle Percentages Modeled VMT HHDT LDA LDT1 LDT2 LHDT1 LHDT2 MCY MDV MH MHDT OBUS SBUS UBUS Condo/Townhouse 1325753 0.6% 49.5% 4.0% 23.6% 2.8% 0.7% 2.2% 14.5% 0.4% 1.6% 0.1% 0.1% 0.0% Condo/Townhouse Fuel Consumption by Vehicle Category
Fuel Consumption for CVMT Units HHDT LDA LDT1 LDT2 LHD1 LHD2 MCY MDV MH MHDT OBUS SBUS UBUS Gasoline gal 1 18306 1983 11647 1539 284 692 8666 631 736 83 43 11 Diesel gal 1073 31 0 36 628 326 0 101 166 1788 38 54 0
Natural Gas gal 136 0 0 0 0 0 0 0 0 20 6 107 109
Plug-in Hybrid (Gasoline) gal 0 337 3 56 0 0 0 37 0 0 0 0 0 Fuel Consumption for EVMT Units HHDT LDA LDT1 LDT2 LHD1 LHD2 MCY MDV MH MHDT OBUS SBUS UBUS Electricity kwhr 237 18796 97 1374 438 114 0 1455 0 415 9 20 5 Plug-in Hybrid (Electricity) kwhr 0 3417 34 616 0 0 0 389 0 0 0 0 0 County and Year Specific - Fuel Efficiency
Fuel Consumption Factors Units HHDT LDA LDT1 LDT2 LHDT1 LHDT2 MCY MDV MH MHDT OBUS SBUS UBUS 127 Gasoline gal/mi 0.222 0.031 0.038 0.038 0.067 0.077 0.024 0.047 0.205 0.190 0.186 0.111 0.077 Diesel gal/mi 0.161 0.023 0.040 0.030 0.048 0.056 - 0.040 0.098 0.111 0.135 0.134 - Natural Gas gal/mi 0.162 - - - - - - - - 0.117 0.108 0.229 0.336 Plug-in Hybrid gal/mi - 0.035 0.035 0.035 - - - 0.036 - - - - - Fuel Consumption Factors Units HHDT LDA LDT1 LDT2 LHDT1 LHDT2 MCY MDV MH MHDT OBUS SBUS UBUS Electricity kwhr/mi 1.810 0.386 0.386 0.386 0.563 0.563 - 0.386 - 1.051 1.042 1.156 2.127 Plug-in Hybrid kwhr/mi - 0.302 0.302 0.302 - - - 0.302 - - - - - Appendix A 123 356
Argonaut Residential
Energy Calculations - Operations Fuel Use from On-Road Mobile Sources Total VMT Fraction by Fuel and Vehicle Category - Default EMFAC Fuel HHDT LDA LDT1 LDT2 LHDT1 LHDT2 MCY MDV MH MHDT OBUS SBUS UBUS 144 Gasoline 0% 89% 99% 97% 62% 38% 100% 96% 65% 19% 56% 30% 31% Diesel 87% 0.2% 0.0% 0.4% 35.8% 60.0% 0.0% 1.3% 35.4% 78.5% 35.8% 31.6% 0.0% Natural Gas 11% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.8% 6.8% 36.6% 68.9% Electricity 2% 7.4% 0.5% 1.1% 2.1% 2.1% 0.0% 2.0% 0.0% 1.9% 1.1% 1.4% 0.5% Plug-in Hybrid 0% 3.2% 0.4% 1.2% 0.0% 0.0% 0.0% 1.2% 0.0% 0.0% 0.0% 0.0% 0.0% totals 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% 100.0% CVMT/Total VMT by EMFAC Vehicle Type
Fuel HHDT LDA LDT1 LDT2 LHDT1 LHDT2 MCY MDV MH MHDT OBUS SBUS UBUS 153 Gasoline 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% Diesel 100% 100% 100% 100% 100% 100% 0% 100% 100% 100% 100% 100% 0% Natural Gas 100% 0% 0% 0% 0% 0% 0% 0% 0% 100% 100% 100% 100% Plug-in Hybrid 0% 46% 42% 44% 0% 0% 0% 44% 0% 0% 0% 0% 0% EVMT/Total VMT by EMFAC Vehicle Type
Fuel HHDT LDA LDT1 LDT2 LHDT1 LHDT2 MCY MDV MH MHDT OBUS SBUS UBUS Electricity 100% 100% 100% 100% 100% 100% 0% 100% 0% 100% 100% 100% 100% Plug-in Hybrid 0% 53.89% 57.95% 56.18% 0.00% 0.00% 0.00% 55.57% 0.00% 0.00% 0.00% 0.00% 0.00% Appendix A 124 357

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358
95 Argonaut Residential Project
Initial Study/Mitigated Negative Declaration
FCS
APPENDIX B:

Biological Resources Supporting
Information
359

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360
MLC Holdings, Inc.—95 Argonaut Residential Project
Biological Resources Assessment Special-status Species Table FirstCarbon Solutions
Table 1: Special-status Plant Species Potentially Occurring within the Project Site Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
Dicots
Aphanisma blitoides
aphanisma
— — 1B.2 Annual herb found in gravelly (sometimes) and
sandy (sometimes) soils in coastal bluff scrub,
coastal dunes, and coastal scrub.

Elevation: 1–305 m
Bloom period: February–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are
three recent and three historical records
between five and ten miles from the project
site.

No
Artemisia palmeri
San Diego sagewort
— — 4.2 Perennial deciduous shrub found in mesic and
sandy soils in chaparral, coastal scrub, riparian
forest, riparian scrub, and riparian woodland.

Elevation: 5–915 m
Bloom period: May–September
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Astragalus brauntonii
Braunton's milk-vetch
FE — 1B.1 Perennial herb found in carbonate and
sandstone soils in chaparral, coastal scrub, and
valley and foothill grassland communities.

Typically found in burned areas and sometimes
in disturbed areas.

Elevation: 4–640 m
Bloom period: January–August
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
recent record between five and ten miles from
the project site.

No
Atriplex coulteri
Coulter’s saltbush
— — 1B.2 Perennial herb found in alkaline or clay soils (sometimes) in coastal bluff scrub, coastal
dunes, coastal scrub, and valley and foothill
grassland communities.

Elevation: 3–460 m
Bloom period: March–October
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are
three historical records within five miles of the
project site and there are three recent and
eight historical records between five and ten
miles from the project site.

No
-
r
361
MLC Holdings, Inc.—95 Argonaut Residential Project
Biological Resources Assessment Special-status Species Table FirstCarbon Solutions
Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
Atriplex pacifica
south coast saltscale
— — 1B.2 Annual herb found in coastal bluff scrub, coastal dunes, coastal scrub, and playas.

Elevation: 0–140 m
Bloom period: March–October
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are
two historical records within five miles of the
project site and one recent and two historical
records between five and ten miles from the
project site.

No
Atriplex parishii
Parish’s brittlescale
— — 1B.1 Annual herb found in alkaline soils in chenopod scrub, playas, and vernal pools.

Elevation: 25–1900 m
Bloom period: June–October
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
historical record within five miles of the project
site. This species may be locally extirpated.

No
Atriplex serenana var.
davidsonii
Davidson’s saltscale
— — 1B.2 Annual herb found in alkaline soils in coastal bluff scrub and coastal scrub.

Elevation: 10–200 m
Bloom period: April–October
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
record within five miles of the project site and
three historical records between five and ten
miles from the project site.

No
Bahiopsis laciniata
San Diego County viguiera
— — 4.3 Perennial shrub found in chaparral and coastal
scrub.

Elevation: 60–750 m
Bloom period: February–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Berberis nevinii
Nevin's Barberry
FE SE 1B.1 Perennial, evergreen shrub found on steep,
north-facing slopes or in low-grade sandy
washes in coastal scrub, chaparral, cismontane
woodland, and riparian scrub communities.

Elevation: 290–1,575 m
Blooming period: March–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
362
MLC Holdings, Inc.—95 Argonaut Residential Project
Biological Resources Assessment Special-status Species Table FirstCarbon Solutions
Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
Camissoniopsis lewisii
Lewis’ evening-primrose
— — 3 Annual herb found in clay and sandy soils
(sometimes) in coastal bluff scrub, cismontane
woodland, coastal dunes, coastal scrub, and
valley and foothill grassland communities.

Elevation: 0–300 m
Bloom period: March–May
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Caulanthus simulans
Payson's jewelflower
— — 4.2 Annual herb found in granitic and sandy soils in chaparral and coastal scrub communities.

Elevation: 90–2,200 m
Bloom period: March–May
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Centromadia parryi ssp.
australis
southern tarplant
— — 1B.1 Annual herb found in marshes and swamps
(margins), valley and foothill grassland (vernally
mesic), and vernal pools.

Elevation: 0–480 m
Bloom period: May–November
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
recent record within five miles of the project
site and six recent and thirteen historical
records between five and ten miles from the
project site.

No
Chaenactis glabriuscula var.
orcuttiana
Orcutt's pincushion
— — 1B.1 Annual herb found in coastal bluff scrub (sandy) and coastal dunes.

Elevation: 0–100 m
Bloom period: January–August
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
historical record within five miles of the project
site and one recent and two historical records
between five and ten miles from the project
site.

No
Chloropyron maritimum
salt marsh bird’s-beak
FE SE 1B.2 Annual, hemiparasitic herb found in coastal
dunes, marsh and swamp, salt marsh, and
wetlands communities.

Elevation: 0–30 m
Bloom period: May–October
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
recent record between five and ten miles from
the project site.

No
363
MLC Holdings, Inc.—95 Argonaut Residential Project
Biological Resources Assessment Special-status Species Table FirstCarbon Solutions
Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
Chorizanthe leptotheca
Peninsular spineflower
— — 4.2 Annual herb found in granitic soils in chaparral, coastal scrub, and lower montane coniferous
forest communities.

Elevation: 300–1,900 m
Bloom period: May–August
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Chorizanthe polygonoides
var. longispina
long-spined spineflower
— — 1B.2 Annual herb that occurs in valley and foothill grassland, coastal scrub, chaparral, meadows
and seeps, and vernal pools.

Elevation: 30–1,530 m
Bloom period: April–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Cistanthe maritima
seaside cistanthe
— — 4.2 Annual herb found in sandy soils in coastal bluff scrub, coastal scrub, and valley and foothill
grassland.

Elevation: 5–300 m
Bloom period: March–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Clinopodium chandleri
San Miguel savory
— — 1B.2 Perennial shrub found in chaparral, cismontane woodland, coastal scrub, riparian woodland, and
valley and foothill grassland. Sometimes in
gabbroic and rocky soils.

Elevation: 120–1,075 m
Bloom period: March–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
record between five and ten miles from the
project site.

No
Comarostaphylis diversifolia
ssp. diversifolia
summer holly
— — 1B.2 Perennial evergreen shrub found in chaparral
and cismontane woodland.

Elevation: 30–790 m
Bloom period: April–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are
one recent and five historical records between
five and ten miles from the project site.

No
Convolvulus simulans
small-flowered morningglory
— — 4.2 Annual herb found in clay soils, seeps, and
serpentine soils in openings in chaparral, coastal
scrub, and valley and foothill grassland
communities.

Elevation: 30–740 m
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
364
MLC Holdings, Inc.—95 Argonaut Residential Project
Biological Resources Assessment Special-status Species Table FirstCarbon Solutions
Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
Bloom period: March–July
Deinandra paniculata
paniculate tarplant
— — 4.2 Annual herb found in sandy soils (sometimes)
and in vernally mesic soils (usually) in coastal
scrub, valley and foothill grassland, vernal pool
communities.

Elevation: 25–940 m
Bloom period: April–November
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Dichondra occidentalis
western dichondra
CONCC
P/HCP
CONCC
P/HCP

4.2 Perennial rhizomatous herb found in chaparral,
cismontane woodland, coastal scrub, and valley
and foothill grassland communities.

Elevation: 50–500 m
Bloom period: March–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Diplacus clevelandii
Cleveland's bush
monkeyflower
— — 4.2 Perennial rhizomatous herb found in chaparral,
cismontane woodland, and lower montane
coniferous forest. In disturbed areas, gabbroic
soils, openings, and rocky areas.

Elevation: 450–2,000 m
Bloom period: April–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Dudleya blochmaniae ssp.
blochmaniae
Blochman's dudleya
CONCC
P/HCP
CONCC
P/HCP
1B.1 Perennial herb found in clay (often), rocky, and
serpentine soils in coastal bluff scrub, chaparral,
coastal scrub, and valley and foothill grassland.

Elevation: 5–450 m
Bloom period: April–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are
four historical records between five and ten
miles from the project site.

No
Dudleya cymosa ssp.
ovatifolia
Santa Monica dudleya
FT
CONCC
P/HCP
CONCC
P/HCP
1B.1 Perennial herb found in chaparral and coastal
scrub, typically in rocky and sometimes volcanic
areas.

Elevation: 150– 1,675 m
Bloom period: March–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
365
MLC Holdings, Inc.—95 Argonaut Residential Project
Biological Resources Assessment Special-status Species Table FirstCarbon Solutions
Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
Dudleya multicaulis
many-stemmed dudleya
— — 1B.2 Perennial herb found in clay soils (usually) in chaparral, coastal scrub, and valley and foothill
grassland communities.

Elevation: 15–790 m
Bloom period: April–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are
three recent and 22 historical records within
five miles of the project site and eight recent
and eighteen historical records between five
and ten miles from the project site.

No
Dudleya stolonifera
Laguna Beach dudleya
FT
CONCC
P/HCP
CT
CONCC
P/HCP
1B.1 Perennial stoloniferous herb found in rocky soils
in chaparral, cismontane woodland, coastal
scrub, and valley and foothill grassland
communities.

Elevation: 10–260 m
Bloom period: May–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
recent record within five miles of the project
site.

No
Dudleya viscida
sticky dudleya
— — 1B.2 Perennial herb found in rocky areas in coastal bluff scrub, chaparral, cismontane woodland,
and coastal scrub.

Elevation: 10–550 m
Bloom period: May–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
historical record between five and ten miles
from the project site.

No
Eryngium pendletonense
Pendleton button-celery
— — 1B.1 Perennial herb found in clay and vernally mesic soils in coastal bluff scrub, valley foothill
grassland, and vernal pools.

Elevation: 15–110 m
Bloom period: April–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Erythranthe diffusa
Palomar monkeyflower
— — 4.3 Annual herb found in gravelly and sandy soils
(sometimes) in chaparral and lower montane
coniferous forest communities.

Elevation: 1,220–1,830 m
Bloom period: April – June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
366
MLC Holdings, Inc.—95 Argonaut Residential Project
Biological Resources Assessment Special-status Species Table FirstCarbon Solutions
Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
Euphorbia misera
Cliff spurge
CONCC
P/HCP
CONCC
P/HCP
2B.2 Perennial shrub found in rocky soils in coastal
bluff scrub, coastal scrub, and Mojavean desert
scrub.

Elevation: 10–500 m
Bloom period: December–August
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are
two recent and two historical records between
five and ten miles from the project site.

No
Harpagonella palmeri
Palmer’s grapplinghook
CONCC
P/HCP
CONCC
P/HCP

4.2 Annual herb found in clay soils and openings in
chaparral, coastal scrub, and valley and foothill
grassland communities.

Elevation: 20–955 m
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
historical record between five and ten miles
from the project site.

No
Helianthus nuttallii ssp.
parishii
Los Angeles sunflower
— — 1A Perennial rhizomatous herb found in marshes
and swamps (freshwater, coastal salt).

Elevation: 10–1525 m
Bloom period: August–October
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
historical record between five and ten miles
from the project site.

No
Holocarpha virgata ssp.
elongata
graceful tarplant
— — 4.2 Annual herb found in chaparral, cismontane
woodland, coastal scrub, and valley and foothill
grassland.

Elevation: 60–1,100 m
Bloom period: May–November
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Horkelia cuneata var.
puberula
mesa horkelia
— — 1B.1 Perennial herb found in chaparral, coastal scrub, and cismontane woodland communities.

Bloom period: February–July
Elevation: 70–810 m
Bloom period: March–May
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
historical record within five miles of the project
site and one historical record between five and
ten miles from the project site.

No
367
MLC Holdings, Inc.—95 Argonaut Residential Project
Biological Resources Assessment Special-status Species Table FirstCarbon Solutions
Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
Isocoma menziesii var.
decumbens
decumbent goldenbush
— — 1B.2 Perennial shrub found in chaparral and coastal scrub (often disturbed areas, sandy).

Elevation: 10–250 m
Bloom period: April–November
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
recent and one historical record between five
and ten miles from the project site.

No
Juglans californica
southern California black
walnut
— — 4.2 Perennial, deciduous tree found in chaparral,
cismontane woodland, coastal scrub, and
riparian woodland communities.

Elevation: 50–900 m
Bloom period: March–August
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Lasthenia glabrata ssp.
coulteri
Coulter’s goldfields
— — 1B.1 Annual herb found in marshes and swamps,
playas, and vernal pools.

Elevation: 1–1,220 m
Bloom period: February–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are
three historical records between five and ten
miles from the project site.

No
Lepechinia cardiophylla
heart-leaved pitcher sage
CONCC
P/HCP
CONCC
P/HCP
1B.2 Perennial shrub found in closed-cone coniferous
forest, chaparral, and cismontane woodland
communities.

Elevation: 520– 1,370 m
Bloom period: April–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Lepidium virginicum var.
robinsonii
Robinson’s pepper-grass
— — 4.3 Annual herb found in dry soils in chaparral and coastal scrub communities.

Elevation: 1–855 m
Bloom period: January–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are
two recent and two historical records between
five and ten miles from the project site.

No
Lessingia hololeuca
woolly-headed lessingia
— — 3 Annual herb found in clay and serpentine soils in broadleafed upland forest, coastal scrub, lower
montane coniferous forest, and valley and
foothill grassland.

None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
368
MLC Holdings, Inc.—95 Argonaut Residential Project
Biological Resources Assessment Special-status Species Table FirstCarbon Solutions
Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
Elevation: 15–305 m
Bloom period: June–October
Lycium brevipes var. hassei
Santa Catalina Island
desert-thorn
— — 3.1 Perennial deciduous shrub found in coastal bluff scrub and coastal scrub communities.

Elevation: 65–300 m
Bloom period: June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Lycium californicum
California box-thorn
— — 4.2 Perennial shrub found in coastal bluff scrub and coastal scrub communities.

Elevation: 5–150 m
Bloom period: March–August
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Malacothrix saxatilis var.
saxatilis
cliff malacothrix
— — 4.2 Perennial rhizomatous herb found in coastal
bluff scrub and coastal scrub communities.

Elevation: 3–200 m
Bloom period: March–September
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Microseris douglasii ssp.
platycarpha
small-flowered microseris
— — 4.2 Annual herb found in clay soils in cismontane
woodland, coastal scrub, valley and foothill
grassland, and vernal pool communities.

Elevation: 15–1,070 m
Bloom period: March–May
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Monardella hypoleuca ssp.
intermedia
intermediate monardella
— — 1B.3 Perennial rhizomatous herb that occurs in
chaparral, cismontane woodland, and lower
montane coniferous forest communities.

Elevation: 400–1,250 m
Bloom period: April–September
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are
three recent records between five and ten miles
from the project site.

No
Monardella macrantha ssp.
hallii
Hall's monardella
— — 1B.3 Perennial rhizomatous herb found in
broadleafed upland forest, chaparral,
cismontane woodland, lower montane
coniferous forest, and valley and foothill
grassland.

Elevation: 730–2,195 m
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
369
MLC Holdings, Inc.—95 Argonaut Residential Project
Biological Resources Assessment Special-status Species Table FirstCarbon Solutions
Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
Bloom period: June–October
Myosurus minimus ssp.
apus
little mousetail
— — 3.1 Annual herb found in alkaline soils in valley and foothill grassland and vernal pools.

Elevation: 20– 640 m
Bloom period: March–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Nama stenocarpa
mud nama
— — 2B.2 Annual/perennial herb found in marshes and
swamps.

Elevation: 5–500 m
Bloom period: January–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are
two historical records within five miles of the
project site and three historical records
between five and ten miles from the project
site.

No
Nasturtium gambelii
Gambel’s water cress
FE CT 1B.1 Perennial rhizomatous herb found in marshes
and swamps (brackish, freshwater).

Elevation: 5–330 m
Bloom period: April–October
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Navarretia prostrata
prostrate vernal pool
navarretia
— — 1B.2 Annual herb found in mesic, alkaline soils in
coastal scrub, meadows and seeps, valley and
foothill grassland, and vernal pool communities.

Elevation: 3–1,210 m
Bloom period: April–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
historical record within five miles of the project
site.

No
Nemacaulis denudata var.
denudata
coast woolly-heads
— — 1B.2 Annual herb found in coastal dunes.

Elevation: 0–100 m
Bloom period: April–September
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
recent and one historical record within five
miles of the project site and two historical
No
370
MLC Holdings, Inc.—95 Argonaut Residential Project
Biological Resources Assessment Special-status Species Table FirstCarbon Solutions
Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
records between five and ten miles from the
project site.

Pentachaeta aurea ssp.
allenii
Allen’s pentachaeta
— — 1B.1 Annual herb found in openings in coastal scrub and valley and foothill grassland communities.

Elevation: 75–520 m
Bloom period: March–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are
three historical records within five miles of the
project site and three historical records
between five and ten miles from the project
site.

No
Pentachaeta aurea ssp.
aurea
golden-rayed pentachaeta
— — 4.2 Annual herb found in chaparral, cismontane
woodland, coastal scrub, lower montane
coniferous forest, riparian woodland, and valley
and foothill grassland communities.

Elevation: 80–1,850 m
Bloom period: March–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Phacelia hubbyi
Hubby's phacelia
— — 4.2 Annual herb found in gravelly, rocky, and talus soils in chaparral, coastal scrub, and valley and
foothill grassland.

Elevation: 0–1,000 m
Bloom period: April–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Phacelia keckii
Santiago Peak phacelia
— — 1B.3 Annual herb found in closed-cone coniferous
forest and chaparral communities.

Elevation: 545–1,600 m
Bloom period: May–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Phacelia ramosissima var.
austrolitoralis
south coast branching
phacelia
— — 3.2 Perennial herb found in rocky (sometimes) and
sandy soils in chaparral, coastal dunes, coastal
scrub, and marshes and swamps (coastal salt).

Elevation: 5–300 m
Bloom period: March–August
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
371
MLC Holdings, Inc.—95 Argonaut Residential Project
Biological Resources Assessment Special-status Species Table FirstCarbon Solutions
Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
Pseudognaphalium
leucocephalum
white rabbit-tobacco
— — 2B.2 Perennial herb found in gravelly and sandy soils in chaparral, cismontane woodland, coastal
scrub, and riparian woodland communities.

Elevation: 0–2,100 m
Bloom period: August–November
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
historical record within five miles of the project
site and three recent and two historical records
between five and ten miles from the project
site.

No
Quercus dumosa
Nuttall’s scrub oak
CONCC
P/HCP
CONCC
P/HCP
1B.1 Perennial evergreen shrub found in clay, loam,
and sandy soils in closed-cone coniferous forest,
chaparral, and coastal scrub.

Elevation: 15–400 m
Bloom period: February–April
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
historical record within five miles of the project
site and three recent and five historical records
between five and ten miles from the project
site.

No
Rhinotropis cornuta var.
fishiae
Fish's milkwort
— — 4.3 Perennial deciduous shrub found in chaparral,
cismontane woodland, and riparian woodland
communities.

Elevation: 100–1,000 m
Bloom period: May–August
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Romneya coulteri
Coulter's matilija poppy
CONCC
P/HCP
CONCC
P/HCP

4.2 Perennial, rhizomatous herb found in chaparral
and coastal scrub, often in burned areas.

Elevation: 20–1,200 m
Bloom period: March–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Senecio aphanactis
chaparral ragwort
— — 2B.2 Annual herb found in drying alkaline flats
(usually) in chaparral, cismontane woodland,
and coastal scrub communities.

Elevation: 15–800 m
Bloom period: January–April
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are
three historical records between five and ten
miles from the project site.

No
372
MLC Holdings, Inc.—95 Argonaut Residential Project
Biological Resources Assessment Special-status Species Table FirstCarbon Solutions
Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
Sidalcea neomexicana
salt spring checkerbloom
— — 2B.2 Perennial herb found in playas and in alkaline, mesic soils in chaparral, coastal scrub, lower
montane coniferous forest, and Mojavean
desert scrub communities.

Elevation: 15–1,500 m
Bloom period: March–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
recent and one historical record between five
and ten miles from the project site.

No
Suaeda esteroa
estuary seablite
— — 1B.2 Perennial herb found in marshes and swamps
(coastal salt).

Elevation: 0–5 m
Bloom period: July–October
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are
two recent and one historical record between
five and ten miles from the project site.

No
Suaeda taxifolia
woolly seablite
— — 4.2 Perennial evergreen shrub found in coastal bluff scrub, coastal dunes, and marshes and swamps
(coastal margins).

Elevation: 0–50 m
Bloom period: January–December
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Symphyotrichum defoliatum
San Bernardino aster
— — 1B.2 Perennial, rhizomatous herb found in banks of
ditches, streams, and springs in cismontane
woodlands, coastal scrub, lower montane
coniferous forests, meadows and seeps,
marshes and swamps, and vernally mesic valley
and foothill grassland communities.

Elevation: 2–2,040 m
Bloom period: July–November
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are
two historical records between five and ten
miles from the project site.

No
Verbesina dissita
big-leaved crownbeard
FT CT 1B.1 Perennial herb found in chaparral (maritime) and coastal scrub communities.

Elevation: 45–205 m
Bloom period: April–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
recent record within five miles of the project
site and one recent record between five and ten
miles from the project site.

No
373
MLC Holdings, Inc.—95 Argonaut Residential Project
Biological Resources Assessment Special-status Species Table FirstCarbon Solutions
Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
Ferns
Asplenium vespertinum
western spleenwort
— — 4.2 Perennial, rhizomatous herb found in rocky
areas in chaparral, cismontane woodland, and
coastal scrub.

Elevation: 180–1,000 m
Bloom period: February–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Gymnosperms
Hesperocyparis forbesii
Tecate cypress
CONCC
P/HCP
CONCC
P/HCP
1B.1 Perennial, evergreen tree found in clay and
gabbroic (sometimes) soils in closed-cone
coniferous forest and chaparral communities.

Elevation: 80–1,500 m
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Lycophytes
Selaginella cinerascens
ashy spike-moss
— — 4.1 Perennial rhizomatous herb found in chaparral
and coastal scrub communities.

Elevation: 20–640 m
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Monocots
Allium marvinii
Yucaipa onion
— — 1B.2 Perennial, bulbiferous herb found in clay soils and openings in chaparral.

Elevation: 760–1,065 m
Bloom period: April–May
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Brodiaea filifolia
thread-leaved brodiaea
FT CE 1B.1 Perennial, bulbiferous herb found in clay soils in chaparral (openings), cismontane woodland,
coastal scrub, playas, valley and foothill
grassland, and vernal pools.

Elevation: 25–1,120 m
Bloom period: March–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
recent and one historical record within five
miles of the project site and five recent and four
historical records between five and ten miles
from the project site.

No
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Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
Calochortus catalinae
Catalina mariposa lily
CONCC
P/HCP
CONCC
P/HCP

4.2 Perennial, bulbiferous herb found in chaparral,
cismontane woodland, coastal scrub, and valley
and foothill grassland communities.

Elevation: 15–700 m
Bloom period: March–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Calochortus plummerae
Plummer's mariposa-lily
— — 4.2 Perennial, bulbiferous herb found in granitic and rocky soils in chaparral, cismontane woodland,
coastal scrub, lower montane coniferous forest,
and valley and foothill grassland communities.

Elevation: 100– 1,700 m
Bloom period: May–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Calochortus weedii var.
intermedius
intermediate mariposa-lily
CONCC
P/HCP
CONCC
P/HCP
1B.2 Perennial, bulbiferous herb that occurs in
calcareous soils on rocky sites in coastal scrub,
chaparral, and valley and foothill grassland
communities.

Elevation: 105–855 m
Bloom period: May–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are
twelve recent and nine historical records within
five miles of the project site and 36 recent and
sixteen historical records between five and ten
miles from the project site.

No
Hordeum intercedens
vernal barley
— — 3.2 Annual herb found in vernal pools and
depressions and saline flats in coastal dunes,
coastal scrub, and valley and foothill grassland
communities.

Elevation: 5–1,000 m
Bloom period: March–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Imperata brevifolia
California satintail
— — 2B.1 Perennial rhizomatous herb found in mesic soils in chaparral, coastal scrub, Mojavean desert
scrub, meadows and seeps (often alkali), and
riparian scrub.

Elevation: 0–1,215 m
Bloom period: September–May
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There is one
historical record between five and ten miles
from the project site.

No
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Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
Juncus acutus ssp. leopoldii
southwestern spiny rush
— — 4.2 Perennial, rhizomatous herb found in mesic soils in coastal dunes, meadows and alkaline seeps
and coastal salt marshes and swamps.

Elevation: 3–900 m
Bloom period: May–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Lilium humboldtii ssp.
ocellatum
ocellated Humboldt lily
— — 4.2 Perennial, bulbiferous herb found in openings in chaparral, cismontane woodland, coastal scrub,
lower montane coniferous forest, and riparian
woodland communities.

Elevation: 30–1,800 m
Bloom period: March–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Nolina cismontana
chaparral nolina
— — 1B.2 Perennial, evergreen shrub occurring in
gabbroic soils and sandstone (sometimes) in
chaparral and coastal scrub communities.

Elevation: 140–1,275 m
Bloom period: May–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species. There are six
recent and two historical records between five
and ten miles from the project site.

No
Orcuttia californica
California Orcutt grass
FE CE 1B.1 Annual herb found in vernal pools.

Elevation: 15–660 m
Bloom period: April–August
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Piperia cooperi
chaparral rein orchid
— — 4.2 Perennial herb found in chaparral, cismontane
woodland, and valley and foothill grassland.

Elevation: 15–1,585 m
Bloom period: March–June
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Piperia leptopetala
narrow-petaled rein orchid
— — 4.3 Perennial herb found in cismontane woodland,
lower montane coniferous forest, and upper
montane coniferous forest.

Elevation: 380–2,225 m
Bloom period: May–July
None: The project site has been subjected to
significant historical surface disturbances and
does not contain suitable habitat(s) that would
support occurrence of this species.

No
Code Designations
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Scientific Name
Common Name
Status
Habitat Description4 Potential to Occur and Rationale5
Included in
USFWS Impact Analysis 1 CDFW2 CNPS3
1 Federal Status: 2025 USFWS Listing 2 State Status: 2025 CDFW Listing 3 CNPS: 2025 CNPS Listing FE = Listed as endangered under Federal Endangered
Species Act (FESA)
FT = Listed as threatened under FESA
FC = Candidate for listing (threatened or endangered)
under FESA
FD = Delisted in accordance with FESA
FPD = Federally Proposed to be Delisted
— = Not federally listed
SE = Listed as endangered under California Endangered
Species Act (CESA)
ST = Listed as threatened under CESA
SC = Candidate for listing (threatened or endangered)
under CESA
CR = Rare in California
— = Not State listed
Rank 1A = Plants species that presumed extinct in
California.

Rank 1B = Plant species that are rare, threatened, or
endangered in California and elsewhere.

Rank 2 = Plant species that are rare, threatened, or
endangered in California, but more common
elsewhere.

Rank 3 = Plants about which we need more information—
A Review List
Rank 4 = Plants of limited distribution—A Watch List
CBR = Considered But Rejected
Blooming period: Months in parentheses are uncommon.

Notes:
4 Habitat Description: Habitat description adapted from CNDDB and CNPS online inventory or other specified source. 5 Potential to Occur and Rationale: Location of recorded species occurrences determined by geospatial information from BIOS 6 or other specified source.

Sources:

California Department of Fish and Wildlife (CDFW). 2024. CNDDB RareFind 5 California Natural Diversity Database Query for Special-Status Species. Website:
https://map.dfg.ca.gov/rarefind/view/RareFind.aspx. Accessed November 27, 2024.

California Native Plant Society (CNPS). 2024. California Native Plant Society Rare and Endangered Plant Inventory. Website: http://www.rareplants.cnps.org/. Accessed November 27, 2024.

California Department of Fish and Wildlife (CDFW). 2024. Biogeographic Information and Observation System (BIOS 6). Website: https://map.dfg.ca.gov/bios/. Accessed November 27, 2024.

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Table 2: Special-status Wildlife Species Potentially Occurring within the Project Scientific Name
Common Name
Status
Habitat Description3 Potential to Occur and Rationale4
Included in Impact
USFWS Analysis 1 CDFW2
Insects
Bombus crotchii
Crotch bumble
bee
— SC This species occurs primarily in California,
including coastal habitats, western Mojave
Desert, San Joaquin Valley, and adjacent foothills
through most of southwestern California. It
inhabits arid grasslands and shrublands, and its
food sources including milkweeds, pincushions,
lupines, clovers, phacelias, sages, clarkias,
poppies, and buckwheats.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
recent and one historical record within five
miles of the project site and five recent
records between five and ten miles from the
project site.

No
Bombus
pensylvanicus
American
bumble bee
— — Occurs in coastal prairie, Great Basin grassland,
and valley & foothill grassland communities. Nests
above ground under long grass or underground.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are 14
recent and two historical records within five
miles of the project site and 44 recent and six
historical records between five and ten miles
from the project site.

No
Cicindela
hirticollis gravida
sandy beach
tiger beetle
— — Occurs in coastal dunes adjacent to non-brackish
water along the coast of California from San
Francisco Bay to northern Mexico.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
historical record between five and ten miles
from the project site. This species is believed
to be locally extirpated.

No
Cicindela
latesignata
western beach
tiger beetle
— — Occurs in mudflats and beaches of coastal
estuaries from San Diego County to Los Angeles
County. Typically inhabit wet or dry sandy
beaches and mud, sand, or salt flats.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are two
historical records between five and ten miles
from the project site.

No
Coelus globosus
globose dune
beetle
— — Occurs in coastal sand dune habitat. Inhabits
foredunes and sand hummocks; burrows beneath
the sand surface and is most common beneath
dune vegetation.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
historical record between five and ten miles
from the project site.

No
I I I
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Danaus
plexippus
monarch
butterfly
(California
overwintering
population)
FC — Occurs in temperate climates, such as eastern and
western North America and undergoes longdistance migration. Lays eggs on obligate milkweed host plant (primarily Asclepias spp.).

Roosts located in wind protected Eucalyptus,
Monterey pine, and Cypress tree groves with
nectar and water sources nearby
None: The project site does not contain
suitable overwintering habitat or the obligate
host plant that would support occurrence of
this species.

No
Habroscelimorph
a gabbii
western tidal-flat
tiger beetle
— — Occurs in estuaries and mudflats along the coast
of Southern California. Generally found on darkcolored mud in the lower zone; occasionally found on dry saline flats of estuaries.

No
Mollusks
Tryonia imitator
mimic tryonia
(=California
brackishwater
snail)
— — Occurs in coastal lagoons, estuaries and salt
marshes, from Sonoma County south to San Diego
County. Found only in permanently submerged
areas in a variety of sediment types; able to
withstand a wide range of salinities.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
historical record between five and ten miles
from the project site.

No
Crustaceans
Branchinecta
sandiegonensis
San Diego fairy
shrimp
FE
CONCC
P/HCP
CONCC
P/HCP
Small, shallow (5-30 cm deep) vernal pools with
cool water (10-20ºC), moderate alkalinity and
conductivity, and less than 1 m deep.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
recent and two historical records between
five and ten miles from the project site.

No
Streptocephalus
woottoni
Riverside fairy
shrimp
FE
CONCC
P/HCP
CONCC
P/HCP
Vernal pools on the Santa Rosa Plateau on
Murrieta stony clay loams, Las Posas series,
Wyman clay loam, and Willows soils.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are three
recent and six historical records between five
and ten miles from the project site.

No
Fish
Eucyclogobius
newberryi
tidewater goby
FE SSC Occurs in shallow lagoons and lower stream
reaches with fairly still but not stagnant water and
high oxygen levels.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
historical record within five miles of the
project site and one historical record
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between five and ten miles from the project
site.

Gila orcuttii
arroyo chub
— SSC Native to the streams and rivers of the Los
Angeles plain in Southern California. Arroyo chub
are adapted to survive in streams that fluctuate
between large winter storm flows, and low
summer flows, and the low dissolved oxygen and
wide temperature fluctuations. Feeds on plants
such as algae and water fern, as well as insects
and mollusks.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are two
historical records within five miles of the
project site and four historical records
between five and ten miles from the project
site.

No
Oncorhynchus
mykiss irideus
pop. 10
steelhead -
southern
California DPS
FE SC Occurs in Pacific coast streams, including the
Santa Ana River.

No
Rhinichthys
gabrielino
Santa Ana
speckled dace
— SSC Occurs in small springs, streams, large rivers, and deep lakes, including headwaters of the Santa Ana
and San Gabriel Rivers.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are two
historical records between five and ten miles
from the project site.

No
Amphibians
Anaxyrus
californicus
arroyo toad
FE
CONCC
P/HCP
SSC
CONCC
P/HCP
Occurs in washes, arroyos, sandy riverbanks,
riparian areas with willows, sycamores, oaks,
cottonwoods. Requires exposed sandy
streamsides with stable terraces for burrowing
with scattered vegetation for shelter, and areas of
quiet water or pools free of predatory fishes with
sandy or gravel bottoms without silt for breeding.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
historical record between five and ten miles
from the project site.

No
Spea hammondii
western
spadefoot
CONCC
P/HCP
SSC
CONCC
P/HCP
Occurs in open areas with sandy or gravelly soils
in mixed woodlands, grasslands, coastal sage and
Riversidean alluvial fan sage scrub, chaparral,
sandy washes, lowlands, river floodplains, alluvial
fans, playas, alkali flats, foothills, and mountains.

Breeds in ephemeral rain pools that do not
contain bullfrogs, fish, or crayfish.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are eight
recent and seven historical records within five
miles of the project site and seventeen recent
and fifteen historical records between five
and ten miles from the project site.

No
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Reptiles
Actinemys
pallida
southwestern
pond turtle
— SSC Occurs in ponds, lakes, rivers, streams, creeks,
marshes, and irrigation ditches with abundant
vegetation, and either rocky or muddy bottoms, in
woodland, forest, and grassland. In streams,
prefers pools to shallower areas. Logs, rocks,
cattail mats, and exposed banks are required for
basking. May enter brackish water and even
seawater.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are one
recent and six historical records within five
miles of the project site and one recent and
eight historical records between five and ten
miles from the project site.

No
Anniella
stebbinsi
southern
California legless
lizard
— SSC Occurs in moist, loose soil in coastal sand dunes and a variety of interior habitats, including sandy
washes and alluvial fans. Tolerant of disturbances.

No
Arizona elegans
occidentalis
California glossy
snake
— SSC Occurs in areas of rocky washes and loose, sandy
soils and for burrowing in desert scrub grassland,
coastal sage and Riversidean alluvial fan sage
scrub, and chaparral habitats. Prefer open sandy
areas with scattered brush, but also found in
rocky areas.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are two
historical records within five miles of the
project site and one historical record
between five and ten miles from the project
site.

No
Aspidoscelis
hyperythra
orange-throated
whiptail
CONCC
P/HCP
WL
CONCC
P/HCP
Occurs primarily on coarse soils in open coastal
sage and Riversidean alluvial fan sage scrub
habitat.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
recent and six historical records within five
miles of the project site and five recent and
ten historical records between five and ten
miles from the project site.

No
Aspidoscelis
tigris stejnegeri
San Diegan
(coastal) whiptail
CONCC
P/HCP
SSC
CONCC
P/HCP
Occurs in dry, open areas with sparse foliage in
coastal sage and Riversidean alluvial fan sage
scrub, chaparral, woodland, and riparian habitats.

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Crotalus ruber
red-diamond
rattlesnake
CONCC
P/HCP
SSC
CONCC
P/HCP
Occurs in arid, rocky areas in creosote scrub,
coastal sage and Riversidean alluvial fan sage
scrub, chaparral, oak and pine woodlands,
grasslands, on cultivated areas.

No
Phrynosoma
blainvillii
coast horned
lizard
CONCC
P/HCP
SSC
CONCC
P/HCP
Occurs in open areas with sandy soil and low
vegetation in grasslands, coniferous forests,
woodlands, and chaparral.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are six
historical records within five miles of the
project site and one recent and twelve
historical records between five and ten miles
from the project site.

No
Salvadora
hexalepis
virgultea
coast patchnosed snake
— SSC Occurs in brushy or shrubby vegetation.

Dependent on small mammal burrows.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
historical record between five and ten miles
from the project site.

No
Thamnophis
hammondii
two-striped
gartersnake
— SSC Occurs in or near permanent fresh water in
marshes and swamps, riparian scrub, riparian
woodlands, and wetlands.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
recent and one historical record within five
miles of the project site and two historical
records between five and ten miles from the
project site.

No
Birds
Accipiter cooperii
Cooper’s hawk

MBTA WL
FGC
Occurs and nests in deciduous and mixed forests
and open woodland habitats. Year-round resident
in southern California, and tolerant of urban areas
with an abundance of trees.

Low: Marginally suitable foraging and nesting
habitat for this species is present in the trees
adjacent to the project site. There is one
recent and two historical records within five
miles of the project site and one recent
record between five and ten miles from the
project site.

No
Agelaius tricolor
tricolored
blackbird

MBTA FT
SSC
FGC
Occurs and nests in large freshwater marshes with
dense stands of hydrophytic vegetation (cattails,
bulrushes, etc.). Short-distance migrant.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are four
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historical records within five miles of the
project site and one recent and five historical
records between five and ten miles from the
project site.

Aimophila
ruficeps
canescens
southern
California rufouscrowned
sparrow
MBTA
CONCC
P/HCP
WL
FGC
CONCC
P/HCP
Occurs and nests on steep, often rocky hillsides
with grass and forb patches in coastal sage and
Riversidean alluvial fan sage scrub and sparse
mixed chaparral habitats. Year-round resident in
southern California.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are fourteen
historical records within five miles of the
project site and four recent and six historical
records between five and ten miles from the
project site.

No
Ammodramus
savannarum
grasshopper
sparrow
MBTA SSC Occurs and nests in dense grasslands on rolling hills, lowland plains, in valleys and on hillsides on
lower mountain slopes.

No
Aquila
chrysaetos
golden eagle
BGEPA
MBTA
CONCC
P/HCP
FP
WL
CONCCP
/HCP
Forages in areas of rolling foothills, mountainous
areas, sage-juniper flats, and desert. Cliff-walled
canyons provide nesting habitat in most parts of
range; also, large trees in open areas.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
record between five and ten miles from the
project site.

No
Asio otus
long-eared owl

MBTA FP
FGC
Occurs and nests in conifer, oak, riparian, pinyonjuniper, and desert woodlands that are either open or are adjacent to grasslands, meadows, or
shrublands.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are four
historical records between five and ten miles
from the project site.

No
Athene
cunicularia
burrowing owl

MBTA SSC
FGC
Occurs and nests in open, dry annual or perennial
grasslands, deserts, and scrublands characterized
by low-growing vegetation. A subterranean
nester, dependent upon burrowing mammals,
most notably the California ground squirrel. Shortdistance migrant.

No
Buteo regalis MBTA WL Occurs in grassland and arid shrublands with an abundance of prey species, such as pocket
None: The project site does not contain
suitable habitat(s) that would support
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ferruginous
hawk
gophers, black-tailed jackrabbits, and desert
cottontails. Will winter near cultivated fields that
have an abundance of pocket gophers.
occurrence of this species. There are two
historical records between five and ten miles
from the project site.

Campylorhynchu
s brunneicapillus
sandiegensis
coastal cactus
wren
MBTA
CONCC
P/HCP
SSC
FGC
CONCC
P/HCP
Occurs and nests in coastal sage scrub. Requires
tall opuntia cactus or Yucca trees for nesting and
roosting.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are ten
historical records within five miles of the
project site and five recent and 32 historical
records between five and ten miles from the
project site.

No
Charadrius
nivosus nivosus
western snowy
plover
FT
MBTA
SSC Occurs in sandy beaches, salt pond levees and
shores of large alkali lakes. Needs sandy, gravelly
or friable soils for nesting.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
recent record between five and ten miles
from the project site.

No
Circus hudsonius
northern harrier
MBTA
CONCC
P/HCP
SSC
BCC
CONCC
P/HCP
Frequents meadows, grasslands, open rangelands,
freshwater emergent wetlands; uncommon in
wooded habitats.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
historical record between five and ten miles
from the project site.

No
Coturnicops
noveboracensis
yellow rail

MBTA SSC
FGC
Occurs in shallow marshes and wet meadows. In
winter, this species inhabits drier fresh-water and
brackish marshes, as well as dense, deep grass,
and rice fields.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
historical record between five and ten miles
from the project site.

No
Elanus leucurus
white-tailed kite

MBTA FP
FGC
Occurs and nests in grasslands and open coastal
scrub in coastal and valley lowlands; rarely found
away from agricultural areas. Inhabits herbaceous,
open stages of most habitats mostly in
cismontane California. Year-round resident in
southern California.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are six
recent records within five miles of the project
site and thirteen recent and one historical
records between five and ten miles from the
project site.

No
Empidonax
traillii extimus
southwestern
willow flycatcher
FE
MBTA
CONCC
P/HCP
SE
CONCC
P/HCP
Occurs and nests in dense riparian woodlands.

Long-distance migrant.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
No
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recent and two historical records between
five and ten miles from the project site.

Eremophila
alpestris actia
California
horned lark

MBTA WL
FGC
Occurs and nests in open areas with sparse
vegetation. Year-round resident in southern
California.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are three
historical records within five miles of the
project site and two historical records
between five and ten miles from the project
site.

No
Icteria virens
yellow-breasted
chat

MBTA SSC
FGC
Occurs and nests in riparian thickets of willow and
other bushy tangles near watercourses. Longdistance migrant.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
recent and one historical record within five
miles of the project site and three historical
records between five and ten miles from the
project site.

No
Laterallus
jamaicensis
coturniculus
California black
rail

MBTA ST
FP
FGC
Occurs and nests in freshwater marshes, wet
meadows, and shallow margins of saltwater
marshes bordering larger bays. Needs water
depths of about 1 inch that do not fluctuate
during the year and dense vegetation for nesting
habitat.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
historical record between five and ten miles
from the project site.

No
Pandion
haliaetus
osprey
MBTA WL Occurs in ocean shore, bays, freshwater lakes, and larger streams.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
recent record between five and ten miles
from the project site.

No
Passerculus
sandwichensis
beldingi
Belding’s
savannah
sparrow
MBTA SE Occurs in coastal wetlands and marshes. None: The project site does not contain suitable habitat(s) that would support
occurrence of this species. There is one
recent record within five miles of the project
site and one historical record between five
and ten miles from the project site.

No
Polioptila
californica
californica
FT
MBTA
CONCC
P/HCP
SSC
FGC
CONCC
P/HCP
Occurs and nests in arid washes, on mesas, and
slopes in coastal sage scrub below 2,500 ft. Yearround resident in California.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are 44
recent and twelve historical records within
No
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coastal California
gnatcatcher
five miles of the project site and 83 recent
and 49 historical records between five and
ten miles from the project site.

Rallus obsoletus
levipes
light-footed
Ridgway's rail
FE
MBTA
SE
FP
Occurs in salt marshes traversed by tidal sloughs,
where cordgrass and pickleweed (required for
nesting or escape cover) are the dominant
vegetation.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are two
recent records between five and ten miles
from the project site.

No
Setophaga
petechia
yellow warbler

MBTA SSC
FGC
Occurs and nests in willow shrubs and thickets,
cottonwoods, sycamores, ash, and alders,
predominantly in riparian habitats. Long-distance
migrant.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
recent record within five miles of the project
site and one recent record between five and
ten miles from the project site.

No
Sternula
antillarum
browni
California least
tern
FE
MBTA
SE
FP
Occurs and nests on bare or sparsely vegetated,
flat substrates: sand beaches, alkali flats, land fills, or paved areas.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
recent and one historical record between five
and ten miles from the project site.

No
Vireo bellii
pusillus
least Bell’s vireo
FE
MBTA
CONCC
P/HCP
SE
CONCC
P/HCP
Occurs and nests in low riparian habitat in the
vicinity of water or in dry river bottoms. Longdistance migrant.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are ten
recent and one historical records within five
miles of the project site and 22 recent and
five historical records between five and ten
miles from the project site.

No
Mammals
Antrozous
pallidus
pallid bat
— SSC Occurs in deserts, grasslands, shrublands,
woodlands, and forests. Most common in open,
dry habitats with rocky areas for roosting. Roosts
must protect bats from high temperatures.

Species is very sensitive to disturbance of roosting
sites.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are two
historical records between five and ten miles
from the project site.

No
Chaetodipus
californicus
femoralis
— — Occurs in coastal scrub, chaparral and grassland in San Diego County.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
No
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Dulzura pocket
mouse
historical record between five and ten miles
from the project site.

Chaetodipus
fallax fallax
northwestern
San Diego pocket
mouse
— SSC Occurs in sandy, herbaceous areas, usually in
association with rocks or coarse gravel, in coastal
sage and Riversidean alluvial fan sage scrub,
chaparral, and grasslands.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
recent record between five and ten miles
from the project site.

No
Eumops perotis
californicus
western mastiff
bat
— SSC Occurs in many open, semi-arid to arid habitats,
including conifer and deciduous woodlands,
coastal scrub, grasslands, chaparral. Roosts in
crevices in cliff faces, high buildings, trees, and
tunnels.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are four
historical records within five miles of the
project site and five records between five and
ten miles from the project site.

No
Lasiurus frantzii
western red bat
— SSC Occurs in cismontane woodland, lower montane
coniferous forest, riparian forest, riparian
woodland. Prefers habitat edges and mosaics with
trees that are protected from above and open
below with open areas for foraging.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
historical record between five and ten miles
from the project site.

No
Myotis
yumanensis
Yuma myotis
— — Occurs in open forests and woodlands with
sources of water over which to feed. Maternity
colonies in caves, mines, buildings or crevices.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
historical record within five miles of the
project site.

No
Neotoma lepida
intermedia
San Diego desert
woodrat
CONCC
P/HCP
SSC
CONCCP
/HCP
Occurs in rock outcrops, rocky cliffs, and slopes in
coastal sage and Riversidean alluvial fan sage
scrub with moderate to dense canopies.

No
Nyctinomops
macrotis
big free-tailed
bat
— SSC Occurs in rocky habitats in arid landscapes and has been found in a variety of plant associations,
including desert shrub, woodlands, and evergreen
forests. Roosts by day in crevices on cliff faces.

These bats forage mostly for large moths, but may
eat other insects as well.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
historical record between five and ten miles
from the project site.

No
Onychomys
torridus ramona
— SSC Occurs in desert areas, especially scrub habitats with friable soils for digging. Prefers low to
moderate shrub cover.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
No
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southern
grasshopper
mouse
recent record between five and ten miles
from the project site.

Perognathus
longimembris
pacificus
Pacific pocket
mouse
FE
CONCC
P/HCP
SSC
CONCC
P/HCP
Occurs in coastal strand, coastal dunes, and
coastal sage scrub growing on marine terraces.

Prefers soils of fine alluvial sands near the ocean.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There are three
historical records between five and ten miles
from the project site.

No
Sorex ornatus
salicornicus
southern
California
saltmarsh shrew
— SSC Occurs in coastal marshes in Los Angeles, Orange
and Ventura counties. Requires dense vegetation
and woody debris for cover.

None: The project site does not contain
suitable habitat(s) that would support
occurrence of this species. There is one
historical record between five and ten miles
from the project site.

No
Code Designations
1 Federal Status: 2025 USFWS Listing 2 State Status: 2025 CDFW Listing ESU = Evolutionary Significant Unit is a distinctive population.

FE = Listed as endangered under the Endangered Species Act.

FT = Listed as threatened under the Endangered Species Act.

FC = Candidate for listing (threatened or endangered) under the Endangered Species Act.

FD = Delisted in accordance with the Endangered Species Act.

FPD = Federally Proposed to be Delisted.

BCC = Bird of Conservation Concern
MBTA= protected by the Migratory Bird Treaty Act
— = Not federally listed
SE = Listed as endangered under the California Endangered Species Act (CESA).

ST = Listed as threatened under the CESA.

SSC = Species of Special Concern as identified by CDFW.

FP = Listed as fully protected under the Fish and Game Code.

FGC = protected by Fish and Game Code 3503-3513
CE = Candidate endangered under CESA.

WL = CDFW Watch List
— = Not State listed
Notes:
3 Habitat Description: Habitat description adapted from CNDDB or other specified source 4 Potential to Occur and Rationale: Location of recorded species occurrences determined by geospatial information from BIOS 6 or other specified source.

Sources:

California Department of Fish and Wildlife (CDFW). 2024. Biogeographic Information and Observation System (BIOS 6). Website: https://map.dfg.ca.gov/bios/. Accessed November 27, 2024.

U.S. Fish and Wildlife Service (USFWS). 2024. Information for Planning and Consultation. Website: https://ecos.fws.gov/ipac/. Accessed November 27, 2024. 388
IPaC resource list
This report is an automatically generated list of species and other resources such as critical habitat (collectively referred to as trust resources) under the U.S. Fish and Wildlife Service's (USFWS) jurisdiction that are known or expected to be on or near the project area referenced below. The list may also include trust resources that occur outside of the project area, but that could potentially be directly or indirectly aected by activities in the project area.

However, determining the likelihood and extent of eects a project may have on trust resources typically requires gathering additional site-specic (e.g., vegetation/species surveys) and project-specic (e.g., magnitude and timing of proposed activities) information.

Below is a summary of the project information you provided and contact information for the USFWS oce(s) with jurisdiction in the dened project area. Please read the introduction to each section that follows (Endangered Species, Migratory Birds, USFWS Facilities, and NWI Wetlands) for additional information applicable to the trust resources addressed in that section.

Location
Orange County, California
Local oce
Carlsbad Fish And Wildlife Oce
 (760) 431-9440
 (760) 431-5901
IPaC U.S. Fish & Wildlife Service
Fm•....,.J • "'
389
2177 Salk Avenue - Suite 250
Carlsbad, CA 92008-7385
390
Endangered species
This resource list is for informational purposes only and does not constitute an analysis of project level impacts.

The primary information used to generate this list is the known or expected range of each species. Additional areas of inuence (AOI) for species are also considered. An AOI includes areas outside of the species range if the species could be indirectly aected by activities in that area (e.g., placing a dam upstream of a sh population even if that sh does not occur at the dam site, may indirectly impact the species by reducing or eliminating water ow downstream). Because species can move, and site conditions can change, the species on this list are not guaranteed to be found on or near the project area. To fully determine any potential eects to species, additional site-specic and project-specic information is often required.

Section 7 of the Endangered Species Act requires Federal agencies to "request of the Secretary information whether any species which is listed or proposed to be listed may be present in the area of such proposed action" for any project that is conducted, permitted, funded, or licensed by any Federal agency. A letter from the local oce and a species list which fullls this requirement can only be obtained by requesting an ocial species list from either the Regulatory Review section in IPaC (see directions below) or from the local eld oce directly.

For project evaluations that require USFWS concurrence/review, please return to the IPaC website and request an ocial species list by doing the following:

1. Draw the project location and click CONTINUE.

2. Click DEFINE PROJECT.

3. Log in (if directed to do so).

4. Provide a name and description for your project.

5. Click REQUEST SPECIES LIST.

Listed species and their critical habitats are managed by the Ecological Services Program of the U.S. Fish and Wildlife Service (USFWS) and the sheries division of the National Oceanic and Atmospheric Administration (NOAA Fisheries ).

Species and critical habitats under the sole responsibility of NOAA Fisheries are not shown on this list. Please contact NOAA Fisheries for species under their jurisdiction.

1. Species listed under the Endangered Species Act are threatened or endangered; IPaC also shows species that are candidates, or proposed, for listing. See the listing status page for more information. IPaC only shows species that are regulated by USFWS (see FAQ). 1 2
391

2. NOAA Fisheries, also known as the National Marine Fisheries Service (NMFS), is an oce of the National Oceanic and Atmospheric Administration within the Department of Commerce.

The following species are potentially aected by activities in this location:

Mammals
Birds
Reptiles

NAME STATUS
Pacic Pocket Mouse Perognathus longimembris pacicus
Wherever found
No critical habitat has been designated for this species. https://ecos.fws.gov/ecp/species/8080
Endangered

NAME STATUS
California Least Tern Sternula antillarum browni
Wherever found
No critical habitat has been designated for this species. https://ecos.fws.gov/ecp/species/8104
Endangered
Coastal California Gnatcatcher Polioptila californica
californica
Wherever found
There is nal critical habitat for this species. Your location does not overlap the critical habitat.
https://ecos.fws.gov/ecp/species/8178
Threatened
Least Bell's Vireo Vireo bellii pusillus
Wherever found
There is nal critical habitat for this species. Your location does not overlap the critical habitat.
https://ecos.fws.gov/ecp/species/5945
Endangered

NAME STATUS
Southwestern Pond Turtle Actinemys pallida
Wherever found
No critical habitat has been designated for this species. https://ecos.fws.gov/ecp/species/4768
Proposed Threatened
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392
Amphibians
Fishes
Insects
Crustaceans

NAME STATUS
Arroyo (=arroyo Southwestern) Toad Anaxyrus californicus Wherever found
There is nal critical habitat for this species. Your location does not overlap the critical habitat.
https://ecos.fws.gov/ecp/species/3762
Endangered
Western Spadefoot Spea hammondii
Wherever found
No critical habitat has been designated for this species. https://ecos.fws.gov/ecp/species/5425
Proposed Threatened

NAME STATUS
Tidewater Goby Eucyclogobius newberryi
Wherever found
There is nal critical habitat for this species. Your location does not overlap the critical habitat.
https://ecos.fws.gov/ecp/species/57
Endangered

NAME STATUS
Monarch Buttery Danaus plexippus
Wherever found
No critical habitat has been designated for this species. https://ecos.fws.gov/ecp/species/9743
Candidate

NAME STATUS
Riverside Fairy Shrimp Streptocephalus woottoni
Wherever found
There is nal critical habitat for this species. Your location does not overlap the critical habitat.
https://ecos.fws.gov/ecp/species/8148
Endangered
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393
Flowering Plants
Critical habitats
Potential eects to critical habitat(s) in this location must be analyzed along with the endangered species themselves.

There are no critical habitats at this location.

You are still required to determine if your project(s) may have eects on all above listed species.

Bald & Golden Eagles
San Diego Fairy Shrimp Branchinecta sandiegonensis
Wherever found
There is nal critical habitat for this species. Your location does not overlap the critical habitat.
https://ecos.fws.gov/ecp/species/6945
Endangered

NAME STATUS
Nevin's Barberry Berberis nevinii
Wherever found
There is nal critical habitat for this species. Your location does not overlap the critical habitat.
https://ecos.fws.gov/ecp/species/8025
Endangered
Thread-leaved Brodiaea Brodiaea lifolia
Wherever found
There is nal critical habitat for this species. Your location does not overlap the critical habitat.
https://ecos.fws.gov/ecp/species/6087
Threatened
Bald and golden eagles are protected under the Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act .

Any person or organization who plans or conducts activities that may result in impacts to bald or golden eagles, or their habitats , should follow appropriate regulations and consider implementing appropriate conservation measures, as described in the links below. 1 2
3 - ---
- ---
394
There are likely bald eagles present in your project area. For additional information on bald eagles, refer to Bald Eagle Nesting and Sensitivity to Human Activity For guidance on when to schedule activities or implement avoidance and minimization measures to reduce impacts to migratory birds on your list, see the PROBABILITY OF PRESENCE SUMMARY below to see when these birds are most likely to be present and breeding in your project area.

BREEDING SEASON
Probability of Presence Summary
The graphs below provide our best understanding of when birds of concern are most likely to be present in your project area. This information can be used to tailor and schedule your project activities to avoid or minimize impacts to birds. Please make sure you read Specically, please review the "Supplemental Information on Migratory Birds and Eagles".

Additional information can be found using the following links:

Eagle Management https://www.fws.gov/program/eagle-management Measures for avoiding and minimizing impacts to birds
https://www.fws.gov/library/collections/avoiding-and-minimizing-incidental-takemigratory-birds Nationwide conservation measures for birds
https://www.fws.gov/sites/default/les/documents/nationwide-standard-conservationmeasures.pdf Supplemental Information for Migratory Birds and Eagles in IPaC https://www.fws.gov/media/supplemental-information-migratory-birds-and-bald-andgolden-eagles-may-occur-project-action NAME
Bald Eagle Haliaeetus leucocephalus
This is not a Bird of Conservation Concern (BCC) in this area, but warrants attention because of the Eagle Act or for potential susceptibilities in oshore areas from certain types of
development or activities.

Breeds Jan 1 to Aug 31
Golden Eagle Aquila chrysaetos
This is not a Bird of Conservation Concern (BCC) in this area, but warrants attention because of the Eagle Act or for potential susceptibilities in oshore areas from certain types of
development or activities.
https://ecos.fws.gov/ecp/species/1680
Breeds Jan 1 to Aug 31
•
•
•
•
--- -- --------
395
"Supplemental Information on Migratory Birds and Eagles", specically the FAQ section titled "Proper Interpretation and Use of Your Migratory Bird Report" before using or attempting to interpret this report.

Probability of Presence ( )
Each green bar represents the bird's relative probability of presence in the 10km grid cell(s) your project overlaps during a particular week of the year. (A year is represented as 12 4- week months.) A taller bar indicates a higher probability of species presence. The survey eort (see below) can be used to establish a level of condence in the presence score. One can have higher condence in the presence score if the corresponding survey eort is also high.

How is the probability of presence score calculated? The calculation is done in three steps:

1. The probability of presence for each week is calculated as the number of survey events in the week where the species was detected divided by the total number of survey events for that week. For example, if in week 12 there were 20 survey events and the Spotted Towhee was found in 5 of them, the probability of presence of the Spotted Towhee in week 12 is 0.25.

2. To properly present the pattern of presence across the year, the relative probability of presence is calculated. This is the probability of presence divided by the maximum probability of presence across all weeks. For example, imagine the probability of presence in week 20 for the Spotted Towhee is 0.05, and that the probability of presence at week 12 (0.25) is the maximum of any week of the year. The relative probability of presence on week 12 is 0.25/0.25 = 1; at week 20 it is 0.05/0.25 = 0.2.

3. The relative probability of presence calculated in the previous step undergoes a statistical conversion so that all possible values fall between 0 and 10, inclusive. This is the probability of presence score.

To see a bar's probability of presence score, simply hover your mouse cursor over the bar.

Breeding Season ( )
Yellow bars denote a very liberal estimate of the time-frame inside which the bird breeds across its entire range. If there are no yellow bars shown for a bird, it does not breed in your project area.

Survey Eort ( )
Vertical black lines superimposed on probability of presence bars indicate the number of surveys performed for that species in the 10km grid cell(s) your project area overlaps. The number of surveys is expressed as a range, for example, 33 to 64 surveys.

To see a bar's survey eort range, simply hover your mouse cursor over the bar.

No Data ( )
A week is marked as having no data if there were no survey events for that week.

Survey Timeframe
396
probability of presence breeding season survey eort no data Surveys from only the last 10 years are used in order to ensure delivery of currently relevant information. The exception to this is areas o the Atlantic coast, where bird returns are based on all years of available data, since data in these areas is currently much more sparse.

SPECIES JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Bald Eagle
Non-BCC
Vulnerable
Golden Eagle
Non-BCC
Vulnerable
What does IPaC use to generate the potential presence of bald and golden eagles in my specied location?
The potential for eagle presence is derived from data provided by the Avian Knowledge Network (AKN). The AKN data is based on a growing collection of survey, banding, and citizen science datasets and is queried and ltered to return a list of those birds reported as occurring in the 10km grid cell(s) which your project intersects, and that have been identied as warranting special attention because they are a BCC species in that area, an eagle (Eagle Act requirements may apply). To see a list of all birds potentially present in your project area, please visit the Rapid Avian Information Locator (RAIL) Tool.

What does IPaC use to generate the probability of presence graphs of bald and golden eagles in my specied location?
The Migratory Bird Resource List is comprised of USFWS Birds of Conservation Concern (BCC) and other species that may warrant special attention in your project location.

The migratory bird list generated for your project is derived from data provided by the Avian Knowledge Network (AKN). The AKN data is based on a growing collection of survey, banding, and citizen science datasets and is queried and ltered to return a list of those birds reported as occurring in the 10km grid cell(s) which your project intersects, and that have been identied as warranting special attention because they are a BCC species in that area, an eagle (Eagle Act requirements may apply), or a species that has a particular vulnerability to oshore activities or development.

Again, the Migratory Bird Resource list includes only a subset of birds that may occur in your project area. It is not representative of all birds that may occur in your project area. To get a list of all birds potentially present in your project area, please visit the Rapid Avian Information Locator (RAIL) Tool.

What if I have eagles on my list?
If your project has the potential to disturb or kill eagles, you may need to obtain a permit to avoid violating the Eagle Act should such impacts occur. Please contact your local Fish and Wildlife Service Field Oce if you have questions.
++++ ++++ ++++
+ I ++ ++++ +ttt +tt+
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397
Migratory birds
The birds listed below are birds of particular concern either because they occur on the USFWS Birds of Conservation Concern (BCC) list or warrant special attention in your project location. To learn more about the levels of concern for birds on your list and how this list is generated, see the FAQ below. This is not a list of every bird you may nd in this location, nor a guarantee that every bird on this list will be found in your project area. To see exact locations of where birders and the general public have sighted birds in and around your project area, visit the E-bird data mapping tool (Tip: enter your location, desired date range and a species on your list). For projects that occur o the Atlantic Coast, additional maps and models detailing the relative occurrence and abundance of bird species on your list are available. Links to additional information about Atlantic Coast birds, and other important information about your migratory bird list, including how to properly interpret and use your migratory bird report, can be found below.

For guidance on when to schedule activities or implement avoidance and minimization measures to reduce impacts to migratory birds on your list, see the PROBABILITY OF PRESENCE SUMMARY below to see when these birds are most likely to be present and breeding in your project area.

BREEDING SEASON
Certain birds are protected under the Migratory Bird Treaty Act and the Bald and Golden Eagle Protection Act .

Any person or organization who plans or conducts activities that may result in impacts to migratory birds, eagles, and their habitats should follow appropriate regulations and consider implementing appropriate conservation measures, as described in the links below.

Specically, please review the "Supplemental Information on Migratory Birds and Eagles".

1. The Migratory Birds Treaty Act of 1918.

2. The Bald and Golden Eagle Protection Act of 1940.

Additional information can be found using the following links:

Eagle Management https://www.fws.gov/program/eagle-management Measures for avoiding and minimizing impacts to birds
https://www.fws.gov/library/collections/avoiding-and-minimizing-incidental-takemigratory-birds Nationwide conservation measures for birds https://www.fws.gov/sites/default/les/ documents/nationwide-standard-conservation-measures.pdf Supplemental Information for Migratory Birds and Eagles in IPaC https://www.fws.gov/media/supplemental-information-migratory-birds-and-bald-andgolden-eagles-may-occur-project-action 1 2
3 NAME
398
Allen's Hummingbird Selasphorus sasin
This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska.
https://ecos.fws.gov/ecp/species/9637
Breeds Feb 1 to Jul 15
Bald Eagle Haliaeetus leucocephalus
This is not a Bird of Conservation Concern (BCC) in this area, but warrants attention because of the Eagle Act or for potential susceptibilities in oshore areas from certain types of
development or activities.

Breeds Jan 1 to Aug 31
Belding's Savannah Sparrow Passerculus sandwichensis
beldingi
This is a Bird of Conservation Concern (BCC) only in particular Bird Conservation Regions (BCRs) in the continental USA https://ecos.fws.gov/ecp/species/8
Breeds Apr 1 to Aug 15
Black Skimmer Rynchops niger
This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska.
https://ecos.fws.gov/ecp/species/5234
Breeds May 20 to Sep 15
Brandt's Cormorant Urile penicillatus
This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska.

Breeds Apr 15 to Sep 15
Bullock's Oriole Icterus bullockii
This is a Bird of Conservation Concern (BCC) only in particular Bird Conservation Regions (BCRs) in the continental USA Breeds Mar 21 to Jul 25
California Gull Larus californicus
This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska.

Breeds Mar 1 to Jul 31
California Thrasher Toxostoma redivivum
This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska.

Breeds Jan 1 to Jul 31
Clark's Grebe Aechmophorus clarkii
This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska.

Breeds Jun 1 to Aug 31
- ---
- ---
- ---
399
Common Yellowthroat Geothlypis trichas sinuosa
This is a Bird of Conservation Concern (BCC) only in particular Bird Conservation Regions (BCRs) in the continental USA https://ecos.fws.gov/ecp/species/2084
Breeds May 20 to Jul 31
Elegant Tern Thalasseus elegans
This is a Bird of Conservation Concern (BCC) only in particular Bird Conservation Regions (BCRs) in the continental USA https://ecos.fws.gov/ecp/species/8561
Breeds Apr 5 to Aug 5
Golden Eagle Aquila chrysaetos
This is not a Bird of Conservation Concern (BCC) in this area, but warrants attention because of the Eagle Act or for potential susceptibilities in oshore areas from certain types of
development or activities.
https://ecos.fws.gov/ecp/species/1680
Breeds Jan 1 to Aug 31
Lawrence's Goldnch Spinus lawrencei
This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska.
https://ecos.fws.gov/ecp/species/9464
Breeds Mar 20 to Sep 20
Marbled Godwit Limosa fedoa
This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska.
https://ecos.fws.gov/ecp/species/9481
Breeds elsewhere
Northern Harrier Circus hudsonius
This is a Bird of Conservation Concern (BCC) only in particular Bird Conservation Regions (BCRs) in the continental USA https://ecos.fws.gov/ecp/species/8350
Breeds Apr 1 to Sep 15
Nuttall's Woodpecker Dryobates nuttallii
This is a Bird of Conservation Concern (BCC) only in particular Bird Conservation Regions (BCRs) in the continental USA https://ecos.fws.gov/ecp/species/9410
Breeds Apr 1 to Jul 20
Oak Titmouse Baeolophus inornatus
This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska.
https://ecos.fws.gov/ecp/species/9656
Breeds Mar 15 to Jul 15
--- -- --------
--- -- --------
--- -- --------
--- -- --------
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400
Probability of Presence Summary
The graphs below provide our best understanding of when birds of concern are most likely to be present in your project area. This information can be used to tailor and schedule your project activities to avoid or minimize impacts to birds. Please make sure you read Olive-sided Flycatcher Contopus cooperi
This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska.
https://ecos.fws.gov/ecp/species/3914
Breeds May 20 to Aug 31
Santa Barbara Song Sparrow Melospiza melodia graminea
This is a Bird of Conservation Concern (BCC) only in particular Bird Conservation Regions (BCRs) in the continental USA https://ecos.fws.gov/ecp/species/5513
Breeds Mar 1 to Sep 5
Tricolored Blackbird Agelaius tricolor
This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska.
https://ecos.fws.gov/ecp/species/3910
Breeds Mar 15 to Aug 10
Western Grebe aechmophorus occidentalis
This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska.
https://ecos.fws.gov/ecp/species/6743
Breeds Jun 1 to Aug 31
Western Gull Larus occidentalis
This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska.

Breeds Apr 21 to Aug 25
Western Screech-owl Megascops kennicottii cardonensis
This is a Bird of Conservation Concern (BCC) only in particular Bird Conservation Regions (BCRs) in the continental USA Breeds Mar 1 to Jun 30
Willet Tringa semipalmata
This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska.

Breeds elsewhere
Wrentit Chamaea fasciata
This is a Bird of Conservation Concern (BCC) throughout its range in the continental USA and Alaska.

Breeds Mar 15 to Aug 10
- ---
- ---
- ---
- ---
401
"Supplemental Information on Migratory Birds and Eagles", specically the FAQ section titled "Proper Interpretation and Use of Your Migratory Bird Report" before using or attempting to interpret this report.

How is the probability of presence score calculated? The calculation is done in three steps:

To see a bar's probability of presence score, simply hover your mouse cursor over the bar.

To see a bar's survey eort range, simply hover your mouse cursor over the bar.

No Data ( )
A week is marked as having no data if there were no survey events for that week.

Survey Timeframe
402
probability of presence breeding season survey eort no data Surveys from only the last 10 years are used in order to ensure delivery of currently relevant information. The exception to this is areas o the Atlantic coast, where bird returns are based on all years of available data, since data in these areas is currently much more sparse.

SPECIES JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Allen's
Hummingbird
BCC Rangewide
(CON)
Bald Eagle
Non-BCC
Vulnerable
Belding's
Savannah
Sparrow

BCC - BCR
Black Skimmer
BCC Rangewide
(CON)
Brandt's
Cormorant
BCC Rangewide
(CON)
Bullock's Oriole

BCC - BCR
California Gull
BCC Rangewide
(CON)
California
Thrasher
BCC Rangewide
(CON)
Clark's Grebe
BCC Rangewide
(CON)
Common
Yellowthroat

BCC - BCR
Elegant Tern

BCC - BCR
Golden Eagle
Non-BCC
Vulnerable

SPECIES JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC I+
++++ ++++ tt+t ++++ ++ I I
++++ ++ + ++++
++
++ + + tt+t + I ++ ++++
++++ ++++ ++++
++++ ++++ ++++
+++ +tt+
++++ ++++ ++++
+++ + ++ +tt+
+ t+ + + +t I
+++
I +++ +t++ +tt+ +ttt +tt+
+ I ++ ++++ +ttt +tt+
403
Lawrence's
Goldnch
BCC Rangewide
(CON)
Marbled Godwit
BCC Rangewide
(CON)
Northern
Harrier

BCC - BCR
Nuttall's
Woodpecker

BCC - BCR
Oak Titmouse
BCC Rangewide
(CON)
Olive-sided
Flycatcher
BCC Rangewide
(CON)
Santa Barbara
Song Sparrow

BCC - BCR
Tricolored
Blackbird
BCC Rangewide
(CON)
Western Grebe
BCC Rangewide
(CON)
Western Gull
BCC Rangewide
(CON)
Western
Screech-owl

BCC - BCR
Willet
BCC Rangewide
(CON)

SPECIES JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Wrentit
BCC Rangewide
(CON)
Tell me more about conservation measures I can implement to avoid or minimize impacts to migratory birds.
+++ ++++ ++++ ++ + ++++ ++++ ++++ ++++ ++++ ++++ ++++ ++++ + +tt+ ttt +t I
+ + ++++ ++++ + I I + + +.
++++ ++++ ++++ +++ + ++++ ++++ +tt+
++++ ++++ ++++ ++++ ++++ ++++ ++++ ++++ ++++ ++++ + ++ +tt+ 404
Nationwide Conservation Measures describes measures that can help avoid and minimize impacts to all birds at any location year round. Implementation of these measures is particularly important when birds are most likely to occur in the project area. When birds may be breeding in the area, identifying the locations of any active nests and avoiding their destruction is a very helpful impact minimization measure.

To see when birds are most likely to occur and be breeding in your project area, view the Probability of Presence Summary. Additional measures or permits may be advisable depending on the type of activity you are conducting and the type of infrastructure or bird species present on your project site.

What does IPaC use to generate the list of migratory birds that potentially occur in my specied location?
The Migratory Bird Resource List is comprised of USFWS Birds of Conservation Concern (BCC) and other species that may warrant special attention in your project location.

What does IPaC use to generate the probability of presence graphs for the migratory birds potentially occurring in my specied location?
The probability of presence graphs associated with your migratory bird list are based on data provided by the Avian Knowledge Network (AKN). This data is derived from a growing collection of survey, banding, and citizen science datasets.

Probability of presence data is continuously being updated as new and better information becomes available. To learn more about how the probability of presence graphs are produced and how to interpret them, go the Probability of Presence Summary and then click on the "Tell me about these graphs" link.

How do I know if a bird is breeding, wintering or migrating in my area? To see what part of a particular bird's range your project area falls within (i.e. breeding, wintering, migrating or year-round), you may query your location using the RAIL Tool and look at the range maps provided for birds in your area at the bottom of the proles provided for each bird in your results. If a bird on your migratory bird species list has a breeding season associated with it, if that bird does occur in your project area, there may be nests present at some point within the timeframe specied. If "Breeds elsewhere" is indicated, then the bird likely does not breed in your project area.

What are the levels of concern for migratory birds?
Migratory birds delivered through IPaC fall into the following distinct categories of concern:

1. "BCC Rangewide" birds are Birds of Conservation Concern (BCC) that are of concern throughout their range anywhere within the USA (including Hawaii, the Pacic Islands, Puerto Rico, and the Virgin Islands);
---- ·-----
---- ·-----
405

2. "BCC - BCR" birds are BCCs that are of concern only in particular Bird Conservation Regions (BCRs) in the continental USA; and

3. "Non-BCC - Vulnerable" birds are not BCC species in your project area, but appear on your list either because of the Eagle Act requirements (for eagles) or (for non-eagles) potential susceptibilities in oshore areas from certain types of development or activities (e.g. oshore energy development or longline shing).

Although it is important to try to avoid and minimize impacts to all birds, eorts should be made, in particular, to avoid and minimize impacts to the birds on this list, especially eagles and BCC species of rangewide concern. For more information on conservation measures you can implement to help avoid and minimize migratory bird impacts and requirements for eagles, please see the FAQs for these topics.

Details about birds that are potentially aected by oshore projects For additional details about the relative occurrence and abundance of both individual bird species and groups of bird species within your project area o the Atlantic Coast, please visit the Northeast Ocean Data Portal. The Portal also oers data and information about other taxa besides birds that may be helpful to you in your project review. Alternately, you may download the bird model results les underlying the portal maps through the NOAA NCCOS Integrative Statistical Modeling and Predictive Mapping of Marine Bird Distributions and Abundance on the Atlantic Outer Continental Shelf project webpage.

Bird tracking data can also provide additional details about occurrence and habitat use throughout the year, including migration. Models relying on survey data may not include this information. For additional information on marine bird tracking data, see the Diving Bird Study and the nanotag studies or contact Caleb Spiegel or Pam Loring.

What if I have eagles on my list?
If your project has the potential to disturb or kill eagles, you may need to obtain a permit to avoid violating the Eagle Act should such impacts occur.

Proper Interpretation and Use of Your Migratory Bird Report The migratory bird list generated is not a list of all birds in your project area, only a subset of birds of priority concern. To learn more about how your list is generated, and see options for identifying what other birds may be in your project area, please see the FAQ "What does IPaC use to generate the migratory birds potentially occurring in my specied location". Please be aware this report provides the "probability of presence" of birds within the 10 km grid cell(s) that overlap your project; not your exact project footprint.

On the graphs provided, please also look carefully at the survey eort (indicated by the black vertical bar) and for the existence of the "no data" indicator (a red horizontal bar). A high survey eort is the key component. If the survey eort is high, then the probability of presence score can be viewed as more dependable. In contrast, a low survey eort bar or no data bar means a lack of data and, therefore, a lack of certainty about presence of the species. This list is not perfect; it is simply a starting point for identifying what birds of concern have the potential to be in your project area, when they might be there, and if they might be breeding (which means nests might be present). The list helps you know what to look for to conrm presence, and helps guide you in knowing when to implement conservation measures to avoid or minimize potential impacts from your project activities, should presence be conrmed. To learn more about conservation measures, visit the FAQ "Tell me about conservation measures I can implement to avoid or minimize impacts to migratory birds" at the bottom of your migratory bird trust resources page. 406
Facilities
National Wildlife Refuge lands
Any activity proposed on lands managed by the National Wildlife Refuge system must undergo a 'Compatibility Determination' conducted by the Refuge. Please contact the individual Refuges to discuss any questions or concerns.

There are no refuge lands at this location.

Fish hatcheries
There are no sh hatcheries at this location.

Wetlands in the National Wetlands Inventory
(NWI)
Impacts to NWI wetlands and other aquatic habitats may be subject to regulation under Section 404 of the Clean Water Act, or other State/Federal statutes.

For more information please contact the Regulatory Program of the local U.S. Army Corps of Engineers District.

This location did not intersect any wetlands mapped by NWI.

NOTE: This initial screening does not replace an on-site delineation to determine whether wetlands occur. Additional information on the NWI data is provided below.

Data limitations
The Service's objective of mapping wetlands and deepwater habitats is to produce reconnaissance level information on the location, type and size of these resources. The maps are prepared from the analysis of high altitude imagery. Wetlands are identied based on vegetation, visible hydrology and geography. A margin of error is inherent in the use of imagery; thus, detailed on-the-ground inspection of any particular site may result in revision of the wetland boundaries or classication established through image analysis. ------ --- ---
407
The accuracy of image interpretation depends on the quality of the imagery, the experience of the image analysts, the amount and quality of the collateral data and the amount of ground truth verication work conducted. Metadata should be consulted to determine the date of the source imagery used and any mapping problems.

Wetlands or other mapped features may have changed since the date of the imagery or eld work. There may be occasional dierences in polygon boundaries or classications between the information depicted on the map and the actual conditions on site.

Data exclusions
Certain wetland habitats are excluded from the National mapping program because of the limitations of aerial imagery as the primary data source used to detect wetlands. These habitats include seagrasses or submerged aquatic vegetation that are found in the intertidal and subtidal zones of estuaries and nearshore coastal waters. Some deepwater reef communities (coral or tubercid worm reefs) have also been excluded from the inventory. These habitats, because of their depth, go undetected by aerial imagery.

Data precautions
Federal, state, and local regulatory agencies with jurisdiction over wetlands may dene and describe wetlands in a dierent manner than that used in this inventory. There is no attempt, in either the design or products of this inventory, to dene the limits of proprietary jurisdiction of any Federal, state, or local government or to establish the geographical scope of the regulatory programs of government agencies.

Persons intending to engage in activities involving modications within or adjacent to wetland areas should seek the advice of appropriate Federal, state, or local agencies concerning specied agency regulatory programs and proprietary jurisdictions that may aect such activities. 408
Species Element Code Federal Status State Status Global Rank State Rank Rare Plant
Rank/CDFW
SSC or FP
Accipiter cooperii
Cooper's hawk
ABNKC12040 None None G5 S4 WL
Actinemys pallida
southwestern pond turtle
ARAAD02032 Proposed
Threatened
None G2G3 SNR SSC
Agelaius tricolor
tricolored blackbird
ABPBXB0020 None Threatened G1G2 S2 SSC
Aimophila ruficeps canescens
southern California rufous-crowned sparrow
ABPBX91091 None None G5T3 S4 WL
Ammodramus savannarum
grasshopper sparrow
ABPBXA0020 None None G5 S3 SSC
Anaxyrus californicus
arroyo toad
AAABB01230 Endangered None G2G3 S2 SSC
Anniella stebbinsi
Southern California legless lizard
ARACC01060 None None G3 S3 SSC
Antrozous pallidus
pallid bat
AMACC10010 None None G4 S3 SSC
Aphanisma blitoides
aphanisma
PDCHE02010 None None G3G4 S2 1B.2
Aquila chrysaetos
golden eagle
ABNKC22010 None None G5 S3 FP
Arizona elegans occidentalis
California glossy snake
ARADB01017 None None G5T2 S2 SSC
Asio otus
long-eared owl
ABNSB13010 None None G5 S3? SSC
Aspidoscelis hyperythra
orange-throated whiptail
ARACJ02060 None None G5 S2S3 WL
Aspidoscelis tigris stejnegeri
coastal whiptail
ARACJ02143 None None G5T5 S3 SSC
Astragalus brauntonii
Braunton's milk-vetch
PDFAB0F1G0 Endangered None G2 S2 1B.1
Athene cunicularia
burrowing owl
ABNSB10010 None Candidate
Endangered
G4 S2 SSC
Atriplex coulteri
Coulter's saltbush
PDCHE040E0 None None G3 S2 1B.2
Atriplex pacifica
south coast saltscale
PDCHE041C0 None None G4 S2 1B.2
Atriplex parishii
Parish's brittlescale
PDCHE041D0 None None G1G2 S1 1B.1
Quad IS (Laguna Beach (3311757) OR Santiago Peak (3311765) OR Tustin (3311767) OR El Toro (3311766) OR San Clemente (3311745) OR Canada Gobernadora (3311755) OR Dana Point (3311746) OR San Juan Capistrano (3311756)) Query Criteria:

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Selected Elements by Scientific Name
California Department of Fish and Wildlife
California Natural Diversity Database
409
Species Element Code Federal Status State Status Global Rank State Rank Rare Plant
Rank/CDFW
SSC or FP
Atriplex serenana var. davidsonii
Davidson's saltscale
PDCHE041T1 None None G5T1 S1 1B.2
Bombus crotchii
Crotch's bumble bee
IIHYM24480 None Candidate
Endangered
G2 S2
Bombus pensylvanicus
American bumble bee
IIHYM24260 None None G3G4 S2
Branchinecta sandiegonensis
San Diego fairy shrimp
ICBRA03060 Endangered None G2 S1
Brodiaea filifolia
thread-leaved brodiaea
PMLIL0C050 Threatened Endangered G2 S2 1B.1
Buteo regalis
ferruginous hawk
ABNKC19120 None None G4 S3S4 WL
Calochortus weedii var. intermedius
intermediate mariposa-lily
PMLIL0D1J1 None None G3G4T3 S3 1B.2
Campylorhynchus brunneicapillus sandiegensis
coastal cactus wren
ABPBG02095 None None G5T3Q S2 SSC
Canyon Live Oak Ravine Forest
Canyon Live Oak Ravine Forest
CTT61350CA None None G3 S3.3
Centromadia parryi ssp. australis
southern tarplant
PDAST4R0P4 None None G3T2 S2 1B.1
Chaenactis glabriuscula var. orcuttiana
Orcutt's pincushion
PDAST20095 None None G5T1 S1 1B.1
Chaetodipus californicus femoralis
Dulzura pocket mouse
AMAFD05021 None None G5T3 S3
Chaetodipus fallax fallax
northwestern San Diego pocket mouse
AMAFD05031 None None G5T3T4 S3S4
Choeronycteris mexicana
Mexican long-tongued bat
AMACB02010 None None G3G4 S1 SSC
Chorizanthe polygonoides var. longispina
long-spined spineflower
PDPGN040K1 None None G5T3 S3 1B.2
Cicindela latesignata
western beach tiger beetle
IICOL02110 None None G2G3 S1
Circus hudsonius
northern harrier
ABNKC11011 None None G5 S3 SSC
Clinopodium chandleri
San Miguel savory
PDLAM08030 None None G2G3 S2 1B.2
Coccyzus americanus occidentalis
western yellow-billed cuckoo
ABNRB02022 Threatened Endangered G5T2T3 S1
Coelus globosus
globose dune beetle
IICOL4A010 None None G1G2 S1S2
Comarostaphylis diversifolia ssp. diversifolia
summer holly
PDERI0B011 None None G3T2 S2 1B.2
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Selected Elements by Scientific Name
California Department of Fish and Wildlife
California Natural Diversity Database
410
Species Element Code Federal Status State Status Global Rank State Rank Rare Plant
Rank/CDFW
SSC or FP
Coturnicops noveboracensis
yellow rail
ABNME01010 None None G4 S2 SSC
Crotalus ruber
red-diamond rattlesnake
ARADE02090 None None G4 S3 SSC
Danaus plexippus plexippus pop. 1
monarch - California overwintering population
IILEPP2012 Proposed
Threatened
None G4T1T2Q S2
Dipodomys stephensi
Stephens' kangaroo rat
AMAFD03100 Threatened Threatened G2 S3
Dudleya blochmaniae ssp. blochmaniae
Blochman's dudleya
PDCRA04051 None None G3T2 S2 1B.1
Dudleya multicaulis
many-stemmed dudleya
PDCRA040H0 None None G2 S2 1B.2
Dudleya stolonifera
Laguna Beach dudleya
PDCRA040P0 Threatened Threatened G1 S1 1B.1
Dudleya viscida
sticky dudleya
PDCRA040T0 None None G2 S2 1B.2
Elanus leucurus
white-tailed kite
ABNKC06010 None None G5 S3S4 FP
Empidonax traillii extimus
southwestern willow flycatcher
ABPAE33043 Endangered Endangered G5T2 S3
Eremophila alpestris actia
California horned lark
ABPAT02011 None None G5T4Q S4 WL
Eryngium pendletonense
Pendleton button-celery
PDAPI0Z120 None None G1 S1 1B.1
Eucyclogobius newberryi
tidewater goby
AFCQN04010 Endangered None G3 S3 SSC
Eumops perotis californicus
western mastiff bat
AMACD02011 None None G4G5T4 S3S4 SSC
Euphorbia misera
cliff spurge
PDEUP0Q1B0 None None G5 S2 2B.2
Gila orcuttii
arroyo chub
AFCJB13120 None None G1 S2 SSC
Harpagonella palmeri
Palmer's grapplinghook
PDBOR0H010 None None G4 S3 4.2
Helianthus nuttallii ssp. parishii
Los Angeles sunflower
PDAST4N102 None None G5TX SX 1A
Hesperocyparis forbesii
Tecate cypress
PGCUP040C0 None None G2 S2 1B.1
Horkelia cuneata var. puberula
mesa horkelia
PDROS0W045 None None G4T1 S1 1B.1
Icteria virens
yellow-breasted chat
ABPBX24010 None None G5 S4 SSC
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Selected Elements by Scientific Name
California Department of Fish and Wildlife
California Natural Diversity Database
411
Species Element Code Federal Status State Status Global Rank State Rank Rare Plant
Rank/CDFW
SSC or FP
Imperata brevifolia
California satintail
PMPOA3D020 None None G3 S3 2B.1
Isocoma menziesii var. decumbens
decumbent goldenbush
PDAST57091 None None G3G5T2T3 S2 1B.2
Lasiurus frantzii
western red bat
AMACC05080 None None G4 S3 SSC
Lasthenia glabrata ssp. coulteri
Coulter's goldfields
PDAST5L0A1 None None G4T2 S2 1B.1
Laterallus jamaicensis coturniculus
California black rail
ABNME03041 None Threatened G3T1 S2 FP
Lepechinia cardiophylla
heart-leaved pitcher sage
PDLAM0V020 None None G3 S2S3 1B.2
Lepidium virginicum var. robinsonii
Robinson's pepper-grass
PDBRA1M114 None None G5T3 S3 4.3
Lycium brevipes var. hassei
Santa Catalina Island desert-thorn
PDSOL0G0N0 None None G5T1Q S1 3.1
Monardella hypoleuca ssp. intermedia
intermediate monardella
PDLAM180A4 None None G4T2? S2? 1B.3
Monardella macrantha ssp. hallii
Hall's monardella
PDLAM180E1 None None G5T3 S3 1B.3
Myosurus minimus ssp. apus
little mousetail
PDRAN0H031 None None G5T2Q S2 3.1
Myotis yumanensis
Yuma myotis
AMACC01020 None None G5 S4
Nama stenocarpa
mud nama
PDHYD0A0H0 None None G4G5 S1S2 2B.2
Nasturtium gambelii
Gambel's water cress
PDBRA270V0 Endangered Threatened G1 S1 1B.1
Navarretia prostrata
prostrate vernal pool navarretia
PDPLM0C0Q0 None None G2 S2 1B.2
Neotoma lepida intermedia
San Diego desert woodrat
AMAFF08041 None None G5T3T4 S3S4 SSC
Nolina cismontana
chaparral nolina
PMAGA080E0 None None G3 S3 1B.2
Nyctinomops femorosaccus
pocketed free-tailed bat
AMACD04010 None None G5 S3 SSC
Nyctinomops macrotis
big free-tailed bat
AMACD04020 None None G5 S3 SSC
Oncorhynchus mykiss irideus pop. 10
steelhead - southern California DPS
AFCHA0209J Endangered Candidate
Endangered
G5T1Q S1
Onychomys torridus ramona
southern grasshopper mouse
AMAFF06022 None None G5T3 S3 SSC
Report Printed on Tuesday, January 14, 2025
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Selected Elements by Scientific Name
California Department of Fish and Wildlife
California Natural Diversity Database
412
Species Element Code Federal Status State Status Global Rank State Rank Rare Plant
Rank/CDFW
SSC or FP
Passerculus sandwichensis beldingi
Belding's savannah sparrow
ABPBX99015 None Endangered G5T3 S3
Pentachaeta aurea ssp. allenii
Allen's pentachaeta
PDAST6X021 None None G4T1 S1 1B.1
Perognathus longimembris pacificus
Pacific pocket mouse
AMAFD01042 Endangered None G5T2 S2 SSC
Phacelia keckii
Santiago Peak phacelia
PDHYD0C4G1 None None G1 S1 1B.3
Phrynosoma blainvillii
coast horned lizard
ARACF12100 None None G4 S4 SSC
Plestiodon skiltonianus interparietalis
Coronado skink
ARACH01114 None None G5T5 S2S3 WL
Polioptila californica californica
coastal California gnatcatcher
ABPBJ08081 Threatened None G4G5T3Q S2 SSC
Pseudognaphalium leucocephalum
white rabbit-tobacco
PDAST440C0 None None G4 S2 2B.2
Quercus dumosa
Nuttall's scrub oak
PDFAG050D0 None None G3 S3 1B.1
Rallus obsoletus levipes
light-footed Ridgway's rail
ABNME05014 Endangered Endangered G3T1T2 S1 FP
Rhinichthys gabrielino
Santa Ana speckled dace
AFCJB3705K Proposed
Threatened
None G5T1 S1 SSC
Salvadora hexalepis virgultea
coast patch-nosed snake
ARADB30033 None None G5T4 S3 SSC
Senecio aphanactis
chaparral ragwort
PDAST8H060 None None G3 S2 2B.2
Setophaga petechia
yellow warbler
ABPBX03010 None None G5 S3 SSC
Sidalcea neomexicana
salt spring checkerbloom
PDMAL110J0 None None G4 S2 2B.2
Sorex ornatus salicornicus
southern California saltmarsh shrew
AMABA01104 None None G5T1? S1 SSC
Southern Coast Live Oak Riparian Forest
Southern Coast Live Oak Riparian Forest
CTT61310CA None None G4 S4
Southern Coastal Salt Marsh
Southern Coastal Salt Marsh
CTT52120CA None None G2 S2.1
Southern Cottonwood Willow Riparian Forest
Southern Cottonwood Willow Riparian Forest
CTT61330CA None None G3 S3.2
Southern Dune Scrub
Southern Dune Scrub
CTT21330CA None None G1 S1.1
Southern Foredunes
Southern Foredunes
CTT21230CA None None G2 S2.1
Report Printed on Tuesday, January 14, 2025
Commercial Version -- Dated January, 3 2025 -- Biogeographic Data Branch Page 5 of 6 Information Expires 7/3/2025
Selected Elements by Scientific Name
California Department of Fish and Wildlife
California Natural Diversity Database
413
Species Element Code Federal Status State Status Global Rank State Rank Rare Plant
Rank/CDFW
SSC or FP
Southern Mixed Riparian Forest
Southern Mixed Riparian Forest
CTT61340CA None None G2 S2.1
Southern Riparian Scrub
Southern Riparian Scrub
CTT63300CA None None G3 S3.2
Southern Sycamore Alder Riparian Woodland
Southern Sycamore Alder Riparian Woodland
CTT62400CA None None G4 S4
Spea hammondii
western spadefoot
AAABF02020 Proposed
Threatened
None G2G3 S3S4 SSC
Sternula antillarum browni
California least tern
ABNNM08103 Endangered Endangered G4T2T3Q S2 FP
Streptocephalus woottoni
Riverside fairy shrimp
ICBRA07010 Endangered None G1G2 S2
Suaeda esteroa
estuary seablite
PDCHE0P0D0 None None G3 S2 1B.2
Symphyotrichum defoliatum
San Bernardino aster
PDASTE80C0 None None G2 S2 1B.2
Taricha torosa
Coast Range newt
AAAAF02032 None None G4 S4 SSC
Taxidea taxus
American badger
AMAJF04010 None None G5 S3 SSC
Thamnophis hammondii
two-striped gartersnake
ARADB36160 None None G4 S3S4 SSC
Thamnophis sirtalis pop. 1
south coast gartersnake
ARADB3613F None None G5T1T2 S1S2 SSC
Tryonia imitator
mimic tryonia (=California brackishwater snail)
IMGASJ7040 None None G2 S2
Valley Needlegrass Grassland
Valley Needlegrass Grassland
CTT42110CA None None G3 S3.1
Verbesina dissita
big-leaved crownbeard
PDAST9R050 Threatened Threatened G1G2 S1 1B.1
Vireo bellii pusillus
least Bell's vireo
ABPBW01114 Endangered Endangered G5T2 S3
Record Count: 119
Report Printed on Tuesday, January 14, 2025
Commercial Version -- Dated January, 3 2025 -- Biogeographic Data Branch Page 6 of 6 Information Expires 7/3/2025
Selected Elements by Scientific Name
California Department of Fish and Wildlife
California Natural Diversity Database
414
Search Results
77 matches found. Click on scientific name for details
Search Criteria: , 9-Quad include [3311757:3311765:3311767:3311766:3311745:3311755:3311746:3311756] ▲ SCIENTIFIC
NAME
COMMON

NAME FAMILY LIFEFORM

BLOOMING
PERIOD
FED
LIST
STATE
LIST
GLOBAL
RANK
STATE
RANK
CA
RARE
PLANT
RANK
CA

ENDEMIC
DATE

ADDED PHOTO
Aphanisma
blitoides
aphanisma Chenopodiaceae annual herb Feb-Jun None None G3G4 S2 1B.2 1980- 01-01
© 2010
Larry
Sward
Artemisia palmeri San Diego
sagewort
Asteraceae perennial
deciduous shrub
(Feb)MaySepNone None G3? S3? 4.2 1974-
01-01 No Photo
Available
Asplenium
vespertinum
western
spleenwort
Aspleniaceae perennial
rhizomatous
herb
Feb-Jun None None G3? S4 4.2 1974-
01-01 No Photo
Available
Astragalus
brauntonii
Braunton's
milk-vetch
Fabaceae perennial herb Jan-Aug FE None G2 S2 1B.1 Yes 1974- 01-01
© 2009
Thomas
Stoughton
Atriplex coulteri Coulter's
saltbush
Chenopodiaceae perennial herb Mar-Oct None None G3 S2 1B.2 1994- 01-01 No Photo
Available
Atriplex pacifica south coast
saltscale
Chenopodiaceae annual herb Mar-Oct None None G4 S2 1B.2 1994- 01-01 No Photo
Available
Atriplex parishii Parish's
brittlescale
Chenopodiaceae annual herb Jun-Oct None None G1G2 S1 1B.1 1988- 01-01 No Photo
Available
Atriplex serenana
var. davidsonii
Davidson's
saltscale
Chenopodiaceae annual herb Apr-Oct None None G5T1 S1 1B.2 1994- 01-01 No Photo
Available
Bahiopsis laciniata San Diego
County
viguiera
Asteraceae perennial shrub FebJun(Aug)None None G4 S4 4.3 1974- 01-01 No Photo
Available
CNPS Rare Plant Inventory
415
Brodiaea filifolia thread-leaved
brodiaea
Themidaceae perennial
bulbiferous herb
Mar-Jun FT CE G2 S2 1B.1 Yes 1974-
01-01
© 2016
Keir Morse
Calochortus
catalinae
Catalina
mariposa lily
Liliaceae perennial
bulbiferous herb
(Feb)MarJunNone None G3G4 S3S4 4.2 Yes 1974-
01-01 No Photo
Available
Calochortus
plummerae
Plummer's
mariposa-lily
Liliaceae perennial
bulbiferous herb
May-Jul None None G4 S4 4.2 Yes 1994-
01-01 No Photo
Available
Calochortus weedii
var. intermedius
intermediate
mariposa-lily
Liliaceae perennial
bulbiferous herb
May-Jul None None G3G4T3 S3 1B.2 Yes 1994-
01-01 No Photo
Available
Camissoniopsis
lewisii
Lewis'
eveningprimrose
Onagraceae annual herb MarMay(Jun)None None G4 S4 3 1994- 01-01 No Photo
Available
Caulanthus
simulans
Payson's
jewelflower
Brassicaceae annual herb (Feb)MarMay(Jun)None None G4 S4 4.2 Yes 1974- 01-01 No Photo
Available
Centromadia parryi
ssp. australis
southern
tarplant
Asteraceae annual herb May-Nov None None G3T2 S2 1B.1 1994- 01-01 No Photo
Available
Chaenactis
glabriuscula var.
orcuttiana
Orcutt's
pincushion
Asteraceae annual herb Jan-Aug None None G5T1 S1 1B.1 2001- 01-01 No Photo
Available
Chorizanthe
leptotheca
Peninsular
spineflower
Polygonaceae annual herb May-Aug None None G3 S3 4.2 1994- 01-01 No Photo
Available
Chorizanthe
polygonoides var.
longispina
long-spined
spineflower
Polygonaceae annual herb Apr-Jul None None G5T3 S3 1B.2 1994- 01-01 No Photo
Available
Cistanthe maritima seaside
cistanthe
Montiaceae annual herb (Feb)MarJun(Aug)None None G3G4 S3 4.2 1980- 01-01 No Photo
Available
Clinopodium
chandleri
San Miguel
savory
Lamiaceae perennial shrub Mar-Jul None None G2G3 S2 1B.2 1974- 01-01 No Photo
Available
Comarostaphylis
diversifolia ssp.
diversifolia
summer holly Ericaceae perennial
evergreen shrub
Apr-Jun None None G3T2 S2 1B.2 1980-
01-01 No Photo
Available
Convolvulus
simulans
smallflowered
morning-glory
Convolvulaceae annual herb Mar-Jul None None G4 S4 4.2 1994- 01-01 No Photo
Available
Deinandra
paniculata
paniculate
tarplant
Asteraceae annual herb (Mar)AprNovNone None G4 S4 4.2 2001- 01-01 No Photo
Available
416
Dichondra
occidentalis
western
dichondra
Convolvulaceae perennial
rhizomatous
herb
(Jan)MarJulNone None G3G4 S3S4 4.2 1974-
01-01 No Photo
Available
Diplacus
clevelandii
Cleveland's
bush
monkeyflower
Phrymaceae perennial
rhizomatous
herb
Apr-Jul None None G4 S4 4.2 1980-
01-01
© 2020 W.

Juergen
Schrenk
Dudleya
blochmaniae ssp.
blochmaniae
Blochman's
dudleya
Crassulaceae perennial herb Apr-Jun None None G3T2 S2 1B.1 1974- 01-01
© 2011
Aaron E.

Sims
Dudleya
multicaulis
manystemmed
dudleya
Crassulaceae perennial herb Apr-Jul None None G2 S2 1B.2 Yes 1974- 01-01 No Photo
Available
Dudleya stolonifera Laguna Beach
dudleya
Crassulaceae perennial
stoloniferous
herb
May-Jul FT CT G1 S1 1B.1 Yes 1974-
01-01 No Photo
Available
Dudleya viscida sticky dudleya Crassulaceae perennial herb May-Jun None None G2 S2 1B.2 Yes 1974- 01-01 No Photo
Available
Eryngium
pendletonense
Pendleton
button-celery
Apiaceae perennial herb AprJun(Jul)None None G1 S1 1B.1 Yes 2001- 01-01
© 2009
Vince
Scheidt
Erythranthe diffusa Palomar
monkeyflower
Phrymaceae annual herb Apr-Jun None None G4 S3 4.3 1974- 01-01
Ron
Vanderhoff,
2019
Euphorbia misera cliff spurge Euphorbiaceae perennial shrub (Oct)DecAugNone None G5 S2 2B.2 1974- 01-01 No Photo
Available
Harpagonella
palmeri
Palmer's
grapplinghook
Boraginaceae annual herb Mar-May None None G4 S3 4.2 1980- 01-01
© 2015
Keir Morse
Helianthus nuttallii
ssp. parishii
Los Angeles
sunflower
Asteraceae perennial
rhizomatous
herb
Aug-Oct None None G5TX SX 1A Yes 1974-
01-01 No Photo
Available
Hesperocyparis
forbesii
Tecate
cypress
Cupressaceae perennial
evergreen tree
None None G2 S2 1B.1 1974-
01-01
© 2011
Joey
Malone
417
Holocarpha virgata
ssp. elongata
graceful
tarplant
Asteraceae annual herb May-Nov None None G5T3 S3 4.2 Yes 1994- 01-01
© 2013
Anna
Bennett
Hordeum
intercedens
vernal barley Poaceae annual herb Mar-Jun None None G3G4 S3S4 3.2 1994- 01-01 No Photo
Available
Horkelia cuneata
var. puberula
mesa horkelia Rosaceae perennial herb FebJul(Sep)None None G4T1 S1 1B.1 Yes 2001- 01-01
© 2008
Tony
Morosco
Imperata brevifolia California
satintail
Poaceae perennial
rhizomatous
herb
Sep-May None None G3 S3 2B.1 2006-
12-26
© 2020
Matt C.

Berger
Isocoma menziesii
var. decumbens
decumbent
goldenbush
Asteraceae perennial shrub Apr-Nov None None G3G5T2T3 S2 1B.2 1994- 01-01 No Photo
Available
Juglans californica Southern
California
black walnut
Juglandaceae perennial
deciduous tree
Mar-Aug None None G4 S4 4.2 Yes 1994-
01-01
© 2020
Zoya
Akulova
Juncus acutus ssp.
leopoldii
southwestern
spiny rush
Juncaceae perennial
rhizomatous
herb
(Mar)MayJunNone None G5T5 S4 4.2 1988-
01-01
© 2019
Belinda Lo
Lasthenia glabrata
ssp. coulteri
Coulter's
goldfields
Asteraceae annual herb Feb-Jun None None G4T2 S2 1B.1 1994- 01-01
© 2013
Keir Morse
Lepechinia
cardiophylla
heart-leaved
pitcher sage
Lamiaceae perennial shrub Apr-Jul None None G3 S2S3 1B.2 1974- 01-01
© 2003
Vince
Scheidt
Lepidium
virginicum var.
robinsonii
Robinson's
pepper-grass
Brassicaceae annual herb Jan-Jul None None G5T3 S3 4.3 1994- 01-01
© 2015
Keir Morse
418
Lessingia
hololeuca
woollyheaded
lessingia
Asteraceae annual herb Jun-Oct None None G2G3 S2S3 3 Yes 1994- 01-01
© 2015
Aaron
Schusteff
Lilium humboldtii
ssp. ocellatum
ocellated
Humboldt lily
Liliaceae perennial
bulbiferous herb
MarJul(Aug)None None G4T4? S4? 4.2 Yes 1980-
01-01
© 2008
Thomas
Stoughton
Lycium brevipes
var. hassei
Santa
Catalina
Island desertthorn
Solanaceae perennial
deciduous shrub
Jun(Aug) None None G5T1Q S1 3.1 Yes 1974-
01-01 No Photo
Available
Lycium
californicum
California
box-thorn
Solanaceae perennial shrub MarAug(Dec)None None G4 S4 4.2 2001- 01-01 No Photo
Available
Malacothrix
saxatilis var.
saxatilis
cliff
malacothrix
Asteraceae perennial
rhizomatous
herb
Mar-Sep None None G5T4 S4 4.2 Yes 2001-
01-01 No Photo
Available
Microseris
douglasii ssp.
platycarpha
smallflowered
microseris
Asteraceae annual herb Mar-May None None G4T4 S4 4.2 2001- 01-01
© 2015
Richard
Spellenberg
Monardella
hypoleuca ssp.
intermedia
intermediate
monardella
Lamiaceae perennial
rhizomatous
herb
Apr-Sep None None G4T2? S2? 1B.3 Yes 2012-
10-16
© 2016
Ron
Vanderhoff
Monardella
macrantha ssp.
hallii
Hall's
monardella
Lamiaceae perennial
rhizomatous
herb
Jun-Oct None None G5T3 S3 1B.3 Yes 1974-
01-01 No Photo
Available
Myosurus minimus
ssp. apus
little
mousetail
Ranunculaceae annual herb Mar-Jun None None G5T2Q S2 3.1 1980- 01-01 No Photo
Available
Nama stenocarpa mud nama Namaceae annual/perennial
herb
Jan-Jul None None G4G5 S1S2 2B.2 1994-
01-01 No Photo
Available
Nasturtium
gambelii
Gambel's
water cress
Brassicaceae perennial
rhizomatous
herb
Apr-Oct FE CT G1 S1 1B.1 1980-
01-01 No Photo
Available
Navarretia
prostrata
prostrate
vernal pool
navarretia
Polemoniaceae annual herb Apr-Jul None None G2 S2 1B.2 Yes 2001- 01-01 No Photo
Available
419
Nolina cismontana chaparral
nolina
Ruscaceae perennial
evergreen shrub
(Mar)MayJulNone None G3 S3 1B.2 Yes 2001-
01-01
© 2005
Santa
Monica
Mountains
National
Recreation
Area
Pentachaeta aurea
ssp. allenii
Allen's
pentachaeta
Asteraceae annual herb Mar-Jun None None G4T1 S1 1B.1 Yes 2008- 05-08
©2008 Bob
Allen
Pentachaeta aurea
ssp. aurea
golden-rayed
pentachaeta
Asteraceae annual herb Mar-Jul None None G4T3 S3 4.2 2001- 01-01 No Photo
Available
Phacelia hubbyi Hubby's
phacelia
Hydrophyllaceae annual herb Apr-Jul None None G4 S4 4.2 Yes 2007- 02-02 No Photo
Available
Phacelia keckii Santiago
Peak phacelia
Hydrophyllaceae annual herb May-Jul None None G1 S1 1B.3 Yes 1980- 01-01 No Photo
Available
Phacelia
ramosissima var.
austrolitoralis
south coast
branching
phacelia
Hydrophyllaceae perennial herb Mar-Aug None None G5?T3Q S3 3.2 2007- 05-17 No Photo
Available
Piperia cooperi chaparral rein
orchid
Orchidaceae perennial herb Mar-Jun None None G3 S3S4 4.2 2001- 01-01 No Photo
Available
Piperia leptopetala narrowpetaled rein
orchid
Orchidaceae perennial herb May-Jul None None G4 S4 4.3 Yes 2001- 01-01
©2006
Brad Kelley
Pseudognaphalium
leucocephalum
white rabbittobaccoAsteraceae perennial herb (Jul)AugNov(Dec)None None G4 S2 2B.2 2006- 11-03 No Photo
Available
Quercus dumosa Nuttall's scrub
oak
Fagaceae perennial
evergreen shrub
FebApr(MayAug)
None None G3 S3 1B.1 1994-
01-01 No Photo
Available
Rhinotropis
cornuta var. fishiae
Fish's
milkwort
Polygalaceae perennial
deciduous shrub
May-Aug None None G5T4 S4 4.3 1974-
01-01 No Photo
Available
Romneya coulteri Coulter's
matilija poppy
Papaveraceae perennial
rhizomatous
herb
MarJul(Aug)None None G4 S4 4.2 1974-
01-01 No Photo
Available
ii
420
}
Selaginella
cinerascens
ashy spikemossSelaginellaceae perennial
rhizomatous
herb
None None G3G4 S3? 4.1 1974-
01-01 No Photo
Available
Senecio
aphanactis
chaparral
ragwort
Asteraceae annual herb JanApr(May)None None G3 S2 2B.2 1994- 01-01
Neal
Kramer
Sidalcea
neomexicana
salt spring
checkerbloom
Malvaceae perennial herb Mar-Jun None None G4 S2 2B.2 1994- 01-01 No Photo
Available
Suaeda esteroa estuary
seablite
Chenopodiaceae perennial herb (JanMay)JulOctNone None G3 S2 1B.2 1984- 01-01 No Photo
Available
Suaeda taxifolia woolly
seablite
Chenopodiaceae perennial
evergreen shrub
Jan-Dec None None G4 S3S4 4.2 1994-
01-01 No Photo
Available
Symphyotrichum
defoliatum
San
Bernardino
aster
Asteraceae perennial
rhizomatous
herb
Jul-Nov None None G2 S2 1B.2 Yes 2004-
01-01 No Photo
Available
Verbesina dissita big-leaved
crownbeard
Asteraceae perennial herb (Mar)AprJulFT CT G1G2 S1 1B.1 1984- 01-01 No Photo
Available
Showing 1 to 77 of 77 entries
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Suggested Citation:

California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 14 January 2025]. 421

THIS PAGE INTENTIONALLY LEFT BLANK
422
95 Argonaut Residential Project
Initial Study/Mitigated Negative Declaration
FCS
APPENDIX C:

Cultural Resources Supporting
Information
423

THIS PAGE INTENTIONALLY LEFT BLANK
424
49400049 • 05/2024 | 49400049_record_search.mxd
Exhibit A
Record Search Map
Source: USGS San Juan Capistrano 7.5' Quadrangle / T07S,R08W,sec4,5;T06S,R08W,SEC32,33.

Project Site: USGS San Juan Capistrano 7.5' Quadrangle / T07S,R08W,sec4.

MLC HOLDINGS, INC.

ARGONAUT PROJECT

DUE DILIGENCE MEMORANDUM
I
2,000 1,000 0 2,000
Feet
Project Site
Half-Mile Radius

FIRSTCARBO

SOLUTIONSTM N
425
Primary No. Trinomial
Resource List
Other IDs Type Age Attribute codes Recorded by Reports
P-30-000286 CA-ORA-000286 Resource Name - HOGAN SITE /
LAGUNA CYN #C
OR-01926, OR01995, OR-03441,
OR-03867, OR03937, OR-04247,
OR-04449
Site Prehistoric AP02; AP14; AP15 1970 (McKinney, PCAS) P-30-000414 CA-ORA-000414 Resource Name - Jas-10 OR-00431, OR00702, OR-00926, OR-01073, OR01129, OR-01995,
OR-02089, OR03586
Site Prehistoric AP02; AP15 1973 (Foster; Reeves,
Archaeological Research, Inc);
1988 (Demcak, Carol R., ARM)
P-30-000419 CA-ORA-000419 Resource Name - CSRI 205 OR-00304, OR00431, OR-00702, OR-01439, OR01995, OR-02089
Site Prehistoric AP02; AP08 1973 (COOLEY, RMW Paleo
Associates, Inc.);
1979 (OXENDINE)
P-30-000420 CA-ORA-000420 OR-00431, OR00702, OR-00718, OR-01843, OR01995, OR-02089,
OR-03586, OR04103
Site Prehistoric AP02 1973 (COOLEY, ELLIS, HALL,
RMW Paleo Associates, Inc.);
1979;
2008 (P. Fulton)
P-30-000421 CA-ORA-000421 OR-00431, OR00702, OR-00926, OR-01129, OR01995
Site Prehistoric AP02; AP15 1973 (COOLEY, Archaeological Research, Inc);
1988 (Carol Demcak, ARM)
P-30-000580 CA-ORA-000580 Resource Name - Site 2 OR-00040, OR00255, OR-00824, OR-01873, OR01995, OR-04066,
OR-04366, OR04554
Site Prehistoric AP02; AP15 1975 (Leonard, N.)
P-30-000581 CA-ORA-000581 Resource Name - Site 3 OR-00040, OR00300, OR-00702, OR-00824, OR01873, OR-01995,
OR-02157, OR03125, OR-04305,
OR-04349
Site Prehistoric AP02; AP15 1975 (LEONARD);
1986 (Bissell, Ronald M., RMW)
P-30-000993 CA-ORA-000993 Site Prehistoric AP02 1981 (Schroth; DelChario, OR-04366 Archaeological Resource
Management Corp.)

Page 1 of 2 ends

426
Primary No. Trinomial
Resource List
Other IDs Type Age Attribute codes Recorded by Reports
P-30-001006 CA-ORA-001006 Resource Name - AMH Golf
Course Archaeological Site
OR-01073, OR01127, OR-01721,
OR-02208
Site Prehistoric AP02; AP15 1982 (Schroth; Del Chario,
Archaeological Resource
Management Corp);
1991 (Charleton Jones,
Archaeological Resource
Management Corp);
1998 (R. Bissell, RMW Paleo
Associates)
P-30-100178 Resource Name - AMH Golf
Course Isolate
Other Prehistoric AP02 1998 (R. Bissel, RMW Paleo OR-01721 Associates)

Page 2 of 2 ends

427
Report List
Report No. Other IDs Year Author(s) Title Affiliation Resources OR-00254 1977 Archaeological Report on the Aliso Creek
Specific Plan-planning Unit 1 Located in the
El Toro and Laguna Hills Area of the County
of Orange
Whitney-Desautels,
Nancy A.
30-000016, 30-000354, 30-000355,
30-000388, 30-000394, 30-000415,
30-000514, 30-000536, 30-000544,
30-000566, 30-000579, 30-000604,
30-000628, 30-000659
OR-00255 1977 Archaeological Report on the Aliso Creek
Corridor- Planning Units 2 & 3 Orange
County, California
Scientific Resource
Surveys, Inc.

Anonymous 30-000006, 30-000008, 30-000009,
30-000010, 30-000017, 30-000018,
30-000019, 30-000020, 30-000033,
30-000040, 30-000074, 30-000110,
30-000126, 30-000131, 30-000133,
30-000135, 30-000388, 30-000389,
30-000390, 30-000395, 30-000396,
30-000397, 30-000398, 30-000399,
30-000400, 30-000401, 30-000402,
30-000403, 30-000404, 30-000405,
30-000406, 30-000407, 30-000512,
30-000515, 30-000580
OR-00304 1978 An Archaeological Assessment of Eight
Cultural Localities Along the San OnofreSantiago 220 Kv Transmission Line Dodge, William A. ARCSEARCH 30-000341, 30-000419, 30-000494, 30-000495, 30-000496, 30-000497,
30-000498, 30-000499
OR-00431 1979 Aliso Viejo Cultural/scientific Resources Management Plan
Archaeological Resource
Management Corp.
30-000019, 30-000064, 30-000126,
30-000388, 30-000389, 30-000390,
30-000395, 30-000396, 30-000397,
30-000398, 30-000399, 30-000400,
30-000401, 30-000402, 30-000403,
30-000404, 30-000405, 30-000406,
30-000407, 30-000408, 30-000409,
30-000410, 30-000411, 30-000412,
30-000413, 30-000414, 30-000415,
30-000416, 30-000417, 30-000418,
30-000419, 30-000420, 30-000421,
30-000422, 30-000425, 30-000582,
30-000703
OR-00580 1977 The Aliso Creek Watershed, Orange County, California a Proposal for Creating an
Archaeological District for the National
Register of Historic Places and a Suggested
Research and Study Design
Scientific Resource
Surveys, Inc.

Anonymous

Page 1 of 3 ends

428
Report List
Report No. Other IDs Year Author(s) Title Affiliation Resources OR-00702 1977 Cultural Scientific Resources Report on the Aliso Viejo Company Property Located in the
Southeastern Portion of the County of Orange
Scientific Resource
Surveys, Inc.

Scientific Resource
Surveys, Inc.
30-000006, 30-000013, 30-000017,
30-000019, 30-000020, 30-000126,
30-000177, 30-000266, 30-000388,
30-000389, 30-000390, 30-000395,
30-000396, 30-000397, 30-000398,
30-000399, 30-000400, 30-000401,
30-000402, 30-000403, 30-000404,
30-000405, 30-000406, 30-000407,
30-000408, 30-000409, 30-000410,
30-000411, 30-000412, 30-000413,
30-000414, 30-000415, 30-000416,
30-000417, 30-000418, 30-000419,
30-000420, 30-000421, 30-000422,
30-000425, 30-000581, 30-000582,
30-000604
Paleo -
OR-00705 1973 A Final Report on the Scientific Resources Survey for Moulton Ranch
Archaeological Research,
Inc.

Anonymous 30-000013, 30-000411
OR-00926 1988 Archaeological Investigations at CA-ORA414, CA-ORA-421, and CA-ORA-1006, Laguna Hills, South Orange County, California
Archaeological Resource
Management Corporation
Demcak, Carol R. 30-000414, 30-000421, 30-001007
OR-00945 1982 Rossmoor Business Park Liquidating Trust
Properties
Van Horn, David M. Ultra Systems, Inc. 30-000610
OR-01073 1990 Archaeological Investigations at CA-ORA1006, Locus C Laguna Hills, South Orange County, California
Archaeological Resource
Management Corp.

Jones, Carleton S. and
Demcak, Carol R.
30-000414, 30-001006
OR-01439 1980 National Register Assessment Program of
Cultural Resources of the 230 Kv
Transmission Line Rights-of-way From San
Onofre Nuclear Generating Station to Black
Star Canyon and Santiago Substation and to
Encina and Mission Valley Substation
McCoy, Lesley C. and Westec Services, Inc.

Phillips, Roxana
30-000419, 30-000438, 30-000447,
30-000495, 30-000496, 30-000498,
30-000499, 30-000640, 30-000700,
30-000725, 30-000782, 30-000784,
30-000785, 30-000786, 30-000787,
30-000823, 30-000824, 30-000825,
30-000826, 30-000827, 30-000828,
30-000829, 30-000830, 30-000831,
30-000832, 30-000905
OR-01721 1998 Monitoring of Grading, CA-ORA-1006, Locus C, on the AMH Golf Course Property, Orange
County, California
Bissell, Ronald M. RMW Paleo Associates, Inc. 30-001006, 30-100178 OR-01721 1998 Pollen, Phytolith, and Protein Residue
Analysis of a Metate Fragment from Site CaORA-1006, California Paleo Research
Laboratories
Cummings, Linda Scott,
Thomas E. Moutoux, and
Kathryn Puseman

Page 2 of 3 ends

429
Report List
Report No. Other IDs Year Author(s) Title Affiliation Resources OR-01843 1995 Archaeological Investigations at the Aliso Viejo Sites, South Orange, California
Archaeological Resource
Management Corp.

Demcak, Carol R. and
Maxwell, Pamela C.
30-000017, 30-000019, 30-000126,
30-000408, 30-000409, 30-000410,
30-000411, 30-000416, 30-000417,
30-000420, 30-000425, 30-000703,
30-001211, 30-001212, 30-001213
OR-02404 2001 Cultural Resource Assessment Cingular
Wireless Facility No. SC 021-06 Orange
County, California
Cellular - Duke, Curt LSA Associates, Inc.

OR-03586 2008 Cultural Resources Records Search and Site Visit Results for AT&T Mobility, LLC,
Candidate LAC408 (Laguna Hills/Columbia),
101 Columbia Road, Aliso Viejo, Orange
County, California
Michael Brandman
Associates
Cellular - Bonner, Wayne H. 30-000388, 30-000414, 30-000420

Page 3 of 3 ends

430
STATE OF CALIFORNIA Gavin Newsom, Governor

NATIVE AMERICAN HERITAGE COMMISSION

Page 1 of 2 ends

June 5, 2024
Taylor Love
FirstCarbon Solutions

Via Email to: [email protected] & [email protected] Re: Native American Tribal Consultation, Pursuant to the Assembly Bill 52 (AB 52), Amendments to the California Environmental Quality Act (CEQA) (Chapter 532, Statutes of 2014), Public Resources Code Sections 5097.94 (m), 21073, 21074, 21080.3.1, 21080.3.2, 21082.3, 21083.09, 21084.2 and 21084.3, Argonaut Project, Orange County
To Whom It May Concern:

Pursuant to Public Resources Code section 21080.3.1 (c), attached is a consultation list of tribes that are traditionally and culturally affiliated with the geographic area of the above-listed project. Please note that the intent of the AB 52 amendments to CEQA is to avoid and/or mitigate impacts to tribal cultural resources, (Pub. Resources Code §21084.3 (a)) (“Public agencies shall, when feasible, avoid damaging effects to any tribal cultural resource.”) Public Resources Code sections 21080.3.1 and 21084.3(c) require CEQA lead agencies to consult with California Native American tribes that have requested notice from such agencies of proposed projects in the geographic area that are traditionally and culturally affiliated with the tribes on projects for which a Notice of Preparation or Notice of Negative Declaration or Mitigated Negative Declaration has been filed on or after July 1, 2015. Specifically, Public Resources Code section 21080.3.1 (d) provides:

Within 14 days of determining that an application for a project is complete or a decision by a public agency to undertake a project, the lead agency shall provide formal notification to the designated contact of, or a tribal representative of, traditionally and culturally affiliated California Native American tribes that have requested notice, which shall be accomplished by means of at least one written notification that includes a brief description of the proposed project and its location, the lead agency contact information, and a notification that the California Native American tribe has 30 days to request consultation pursuant to this section.

The AB 52 amendments to CEQA law does not preclude initiating consultation with the tribes that are culturally and traditionally affiliated within your jurisdiction prior to receiving requests for notification of projects in the tribe’s areas of traditional and cultural affiliation. The Native American Heritage Commission (NAHC) recommends, but does not require, early consultation as a best practice to ensure that lead agencies receive sufficient information about cultural resources in a project area to avoid damaging effects to tribal cultural resources.

The NAHC also recommends, but does not require that agencies should also include with their notification letters, information regarding any cultural resources assessment that has been completed on the area of potential effect (APE), such as:

1. The results of any record search that may have been conducted at an Information Center of the California Historical Resources Information System (CHRIS), including, but not limited to:

CHAIRPERSON
Reginald Pagaling
Chumash

VICE-CHAIRPERSON
Buffy McQuillen
Yokayo Pomo, Yuki,
Nomlaki

SECRETARY
Sara Dutschke
Miwok

PARLIAMENTARIAN
Wayne Nelson
LuiseÒo

COMMISSIONER
Isaac Bojorquez
Ohlone-Costanoan

COMMISSIONER
Stanley Rodriguez
Kumeyaay

COMMISSIONER
Laurena Bolden
Serrano

COMMISSIONER
Reid Milanovich
Cahuilla

COMMISSIONER
Bennae Calac
Pauma-Yuima Band of
LuiseÒo Indians

EXECUTIVE SECRETARY
Raymond C.

Hitchcock
Miwok, Nisenan

NAHC HEADQUARTERS
1550 Harbor Boulevard
Suite 100
West Sacramento,
California 95691
(916) 373-3710
[email protected]
431

Page 2 of 2 ends

• A listing of any and all known cultural resources that have already been recorded on or adjacent to the APE, such as known archaeological sites;
• Copies of any and all cultural resource records and study reports that may have been provided by the Information Center as part of the records search response; • Whether the records search indicates a low, moderate, or high probability that unrecorded cultural resources are located in the APE; and
• If a survey is recommended by the Information Center to determine whether previously unrecorded cultural resources are present.

2. The results of any archaeological inventory survey that was conducted, including:
• Any report that may contain site forms, site significance, and suggested mitigation measures.

All information regarding site locations, Native American human remains, and associated funerary objects should be in a separate confidential addendum, and not be made available for public disclosure in accordance with Government Code section 6254.10.

3. The result of the Sacred Lands File (SLF) check conducted through the Native American Heritage Commission was positive. Please contact the Juaneno Band of Mission Indians Acjachemen Nation - Belardes on the attached list for more information.

4. Any ethnographic studies conducted for any area including all or part of the APE; and

5. Any geotechnical reports regarding all or part of the APE.

Lead agencies should be aware that records maintained by the NAHC and CHRIS are not exhaustive and a negative response to these searches does not preclude the existence of a tribal cultural resource. A tribe may be the only source of information regarding the existence of a tribal cultural resource.

This information will aid tribes in determining whether to request formal consultation. In the event that they do, having the information beforehand will help to facilitate the consultation process.

If you receive notification of change of addresses and phone numbers from tribes, please notify the NAHC. With your assistance, we can assure that our consultation list remains current.

If you have any questions, please contact me at my email address: [email protected].

Sincerely,
Andrew Green
Cultural Resources Analyst
Attachment

432
Tribe Name Fed (F)
Non-Fed (N)
Contact Person
Cahuilla Band of Indians F Erica Schenk, Chairperson
Cahuilla Band of Indians F BobbyRay Esaprza, Cultural
Director
Cahuilla Band of Indians F Anthony Madrigal, Tribal Historic Preservation Officer
Gabrieleno Band of Mission Indians - Kizh
Nation
N Christina Swindall Martinez,
Secretary
Gabrieleno Band of Mission Indians - Kizh
Nation
N Andrew Salas, Chairperson
Gabrieleno/Tongva San Gabriel Band of
Mission Indians
N Anthony Morales, Chairperson
Gabrielino Tongva Indians of California
Tribal Council
N Robert Dorame, Chairperson
Gabrielino Tongva Indians of California
Tribal Council
N Christina Conley, Cultural
Resource Administrator
Gabrielino/Tongva Nation N Sandonne Goad, Chairperson
06/05/2024 10:30 AM
1 of 9 433
Gabrielino-Tongva Tribe N Sam Dunlap, Cultural Resource Director
Gabrielino-Tongva Tribe N Charles Alvarez, Chairperson
Juaneno Band of Mission Indians N Sonia Johnston, Chairperson Juaneno Band of Mission Indians
Acjachemen Nation - Belardes
N Joyce Perry, Cultural Resource
Director
Juaneno Band of Mission Indians
Acjachemen Nation 84A
N Heidi Lucero, Chairperson, THPO
La Jolla Band of Luiseno Indians F Norma Contreras, Chairperson Pala Band of Mission Indians F Alexis Wallick, Assistant THPO Pala Band of Mission Indians F Christopher Nejo, Legal
Analyst/Researcher
Pala Band of Mission Indians F Shasta Gaughen, Tribal Historic Preservation Officer
06/05/2024 10:30 AM
2 of 9 434
Pauma Band of Luiseno Indians F Temet Aguilar, Chairperson Santa Rosa Band of Cahuilla Indians F Steven Estrada, Tribal Chairman Santa Rosa Band of Cahuilla Indians F Vanessa Minott, Tribal Administrator
Soboba Band of Luiseno Indians F Joseph Ontiveros, Tribal Historic Preservation Officer
Soboba Band of Luiseno Indians F Jessica Valdez, Cultural Resource Specialist
This list is current only as of the date of this document. Distribution of this list does not relieve This list is only applicable for consultation w
06/05/2024 10:30 AM
3 of 9 435
Contact Address Phone # Fax # Email Address
52701 CA Highway 371
Anza, CA, 92539
(951) 590-0942 (951) 763-2808 [email protected]
52701 CA Highway 371
Anza, CA, 92539
(951) 763-5549 [email protected]
52701 CA Highway 371
Anza, CA, 92539
(951) 763-5549 [email protected]
P.O. Box 393
Covina, CA, 91723
(844) 390-0787 [email protected]
P.O. Box 393
Covina, CA, 91723
(844) 390-0787 [email protected]
P.O. Box 693
San Gabriel, CA, 91778
(626) 483-3564 (626) 286-1262 [email protected]
P.O. Box 490
Bellflower, CA, 90707
(562) 761-6417 (562) 761-6417 [email protected]
P.O. Box 941078
Simi Valley, CA, 93094
(626) 407-8761 [email protected]
u
106 1/2 Judge John Aiso St.,
#231
Los Angeles, CA, 90012
(951) 807-0479 [email protected]
Native American Heritage Commission
Native American Contact List
Orange County
6/5/2024
06/05/2024 10:30 AM
4 of 9 436
Native American Heritage Commission
Native American Contact List
Orange County
6/5/2024
P.O. Box 3919
Seal Beach, CA, 90740
(909) 262-9351 [email protected]
23454 Vanowen Street
West Hills, CA, 91307
(310) 403-6048 [email protected]
P.O. Box 25628
Santa Ana, CA, 92799
[email protected]
4955 Paseo Segovia
Irvine, CA, 92603
(949) 293-8522 [email protected]
31411-A La Matanza Street
San Juan Capistrano, CA, 92675
(562) 879-2884 [email protected]
22000 Highway 76
Pauma Valley, CA, 92061
(760) 742-3771
PMB 50, 35008 Pala Temecula
Road
Pala, CA, 92059
(760) 891-3537 [email protected]
PMB 50, 35008 Pala Temecula
Road
Pala, CA, 92059
(760) 891-3564 [email protected]
PMB 50, 35008 Pala Temecula
Road
Pala, CA, 92059
(760) 891-3515 [email protected]
06/05/2024 10:30 AM
5 of 9 437
Native American Heritage Commission
Native American Contact List
Orange County
6/5/2024
P.O. Box 369
Pauma Valley, CA, 92061
(760) 742-1289 (760) 742-3422 [email protected]
P.O. Box 391820
Anza, CA, 92539
(951) 659-2700 (951) 659-2228 [email protected] P.O. Box 391820
Anza, CA, 92539
(951) 659-2700 (951) 659-2228 [email protected] P.O. Box 487
San Jacinto, CA, 92581
(951) 663-5279 (951) 654-4198 [email protected] P.O. Box 487
San Jacinto, CA, 92581
(951) 663-6261 (951) 654-4198 [email protected]
any person of statutory responsibility as defined in Section 7050.5 of the Health and Safety Code, Section 5097.94 of the P Resources Code.
with Native American tribes under Public Resources Code Sections 21080.3.1 for the proposed Argonaut Project, Orange Co 06/05/2024 10:30 AM
6 of 9 438
Cultural Affiliation Last Updated
Cahuilla 2/1/2024
Cahuilla 6/28/2023
Cahuilla 6/28/2023
Gabrieleno 8/18/2023
Gabrieleno 8/18/2023
Gabrieleno 12/4/2023
Gabrielino 3/16/2023
Gabrielino 3/16/2023
Gabrielino 3/28/2023
Counties
Imperial,Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Imperial,Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Imperial,Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Los Angeles,Orange,Riverside,San
Bernardino,Santa Barbara,Ventura
Los Angeles,Orange,Riverside,San
Bernardino,Santa Barbara,Ventura
Los Angeles,Orange,Riverside,San
Bernardino,Santa Barbara,Ventura
Los Angeles,Orange,Riverside,San
Bernardino,Santa Barbara,Ventura
Los Angeles,Orange,Riverside,San
Bernardino,Santa Barbara,Ventura
Los Angeles,Orange,Riverside,San
Bernardino,Santa Barbara,Ventura
06/05/2024 10:30 AM
7 of 9 439
Gabrielino 5/30/2023
Gabrielino 5/30/2023
Juaneno
Juaneno 3/17/2023
Juaneno 3/28/2023
Luiseno
Cupeno
Luiseno
11/27/2023
Cupeno
Luiseno
11/27/2023
Cupeno
Luiseno
11/27/2023
Los Angeles,Orange,Riverside,San
Bernardino,Santa Barbara,Ventura
Los Angeles,Orange,Riverside,San
Bernardino,Santa Barbara,Ventura
Orange,Riverside,San Diego
Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Orange,Riverside,San Diego
Orange,Riverside,San Bernardino,San Diego
Orange,Riverside,San Bernardino,San Diego
Orange,Riverside,San Bernardino,San Diego
06/05/2024 10:30 AM
8 of 9 440
Luiseno
Cahuilla 4/8/2024
Cahuilla 4/8/2024
Cahuilla
Luiseno
7/14/2023
Cahuilla
Luiseno
7/14/2023
ublic Resources Code and section 5097.98 of the Public
ounty.

Record: PROJ-2024-002895
Report Type: AB52 GIS
Counties: Orange
NAHC Group: All
Orange,Riverside,San Diego
Imperial,Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Imperial,Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Imperial,Los Angeles,Orange,Riverside,San
Bernardino,San Diego
Imperial,Los Angeles,Orange,Riverside,San
Bernardino,San Diego
06/05/2024 10:30 AM
9 of 9 441
MLC Holdings Inc.— Argonaut Project
Due Diligence Memorandum Appendix D
First Carbon Solutions
Photograph 1: Overview of the project site from the northeast corner. View SW.

Photograph 2: Overview of the project site from the northeast corner. View south. 442
MLC Holdings Inc.— Argonaut Project
Due Diligence Memorandum Appendix D
First Carbon Solutions
Photograph 3: Overview of the project site from the northeast corner. View west.

Photograph 4: Overview of the project site from the northwest corner. View SE. 443
MLC Holdings Inc.— Argonaut Project
Due Diligence Memorandum Appendix D
First Carbon Solutions
Photograph 5: Overview of the project site from the northwest corner. View east.

Photograph 6: Overview of the project site from the northwest corner. View south. 444
MLC Holdings Inc.— Argonaut Project
Due Diligence Memorandum Appendix D
First Carbon Solutions
Photograph 7: Overview of the project site from the southwest corner. View NE.

Photograph 8: Overview of the project site from the southwest corner. View north. 445
MLC Holdings Inc.— Argonaut Project
Due Diligence Memorandum Appendix D
First Carbon Solutions
Photograph 9: Overview of the project site from the southwest corner. View east.

Photograph 10: Overview of the main entrance of building. View north. 446
MLC Holdings Inc.— Argonaut Project
Due Diligence Memorandum Appendix D
First Carbon Solutions
Photograph 11: Overview of the project site from the southeast corner. View SW.

Photograph 12: Overview of the project site from the northwest corner. View SW. 447
MLC Holdings Inc.— Argonaut Project
Due Diligence Memorandum Appendix D
First Carbon Solutions
Photograph 13: Overview of the project site from the northwest corner. View north. 448
Counties:

Fresno
Kern
Kings
Madera
Tulare
Inyo
Mono
Keywords:

Buried Sites
Buried Soils
Geoarchaeology
Landform Evolution
Late Quaternary
Owens Valley
Radiocarbon
San Joaquin Valley
Stratigraphy
Submitted to:

California Department of
Transportation, District 6
2015 East Shields Ave
Fresno, CA 93726
Volume I:

A Geoarchaeological Overview
and Assessment of
Caltrans Districts 6 and 9
Cultural Resources Inventory of Caltrans District 6/9
Rural Conventional Highways
EA 06-0A7408 TEA Grant
By:

Jack Meyer
D. Craig Young
Jeffrey S. Rosenthal
February 2010
Prepared and Edited by:

FAR WESTERN ANTHROPOLOGICAL RESEARCH GROUP, INC.
2727 Del Rio Place, Suite A, Davis, California, 95618
http://www.farwestern.com 530-756-3941
449
450
Volume I:

A Geoarchaeological Overview
and Assessment of
Caltrans Districts 6 and 9
Cultural Resources Inventory of Caltrans District 6/9
Rural Conventional Highways
EA 06-0A7408 TEA Grant
By:

Jack Meyer
D. Craig Young
Jeffrey S. Rosenthal
February 2010
Submitted to:

California Department of Transportation, District 6
2015 East Shields Ave
Fresno, CA 93726
451
452
Transportation Enhancement Activities Program i Far Western California Department of Transportation, District 6/9
Geoarchaeological Study

TABLE OF CONTENTS
CHAPTER 1. INTRODUCTION ............................................................................................................ 1 Methods..................................................................................................................................................... 3 Research Agenda ........................................................................................................................................ 3 Climatically Induced Landscape Change ................................................................................................ 4 Pleistocene-Holocene Environmental Change and Human Land Use..................................................... 4 Archaeology in an Active Volcanic Region.............................................................................................. 4 Filling the Middle Holocene Gap........................................................................................................... 5 Structure of the Report............................................................................................................................... 5 CHAPTER 2. ENVIRONMENTAL SETTING........................................................................................ 7 Physical Geography and Hydrology............................................................................................................ 7 Coast Ranges.......................................................................................................................................... 7 Tehachapi Mountains and Transverse Ranges ........................................................................................ 9 San Joaquin Valley ................................................................................................................................. 9 Sierra Nevada ....................................................................................................................................... 10 Great Basin .......................................................................................................................................... 11 Mojave Desert...................................................................................................................................... 12 Contemporary Climate ............................................................................................................................ 12 Coast Ranges........................................................................................................................................ 13 San Joaquin Valley ............................................................................................................................... 13 Sierra Nevada ....................................................................................................................................... 13 Great Basin .......................................................................................................................................... 16 Mojave Desert...................................................................................................................................... 16 CHAPTER 3. EXISTING MODELS AND NOTIONS OF LANDSCAPE CHANGE........................... 17 Sierra Nevada Glacial Sequence................................................................................................................ 18 Great Basin Lake and River Sequence....................................................................................................... 20 Notions of Glaciers and Lakes .............................................................................................................. 22 Notions of the Owens River System ..................................................................................................... 22 San Joaquin Valley Lake Records.......................................................................................................... 25 Conclusions.......................................................................................................................................... 31 The Glacial Model and San Joaquin Valley Depositional Sequence .......................................................... 32 Riverbank Formation ........................................................................................................................... 32 Modesto Formation.............................................................................................................................. 35 Constraining the Ages of Modesto and Post-Modesto Deposits................................................................ 36 Previous Soil-Age Relationships............................................................................................................ 39 Radiocarbon Assessment of “Modesto” Soil-Age Relationships ............................................................. 39 Radiocarbon Assessment of “Post-Modesto” Soil-Age Relationships ..................................................... 43 Conclusions ............................................................................................................................................. 44 453
Far Western ii Transportation Enhancement Activities Program California Department of Transportation, District 6/9
Geoarchaeological Study
CHAPTER 4. AGE OF SURFACE LANDFORMS, REFINED SOIL CHRONOSTRATIGRAPHY, AND MODEL OF LANDSCAPE EVOLUTION.................................................................................... 51 A Climate-Based Model of Landscape Evolution...................................................................................... 51 Refined Soil-Age Relationships, Chronostratigraphy, and the Age of Surface Landforms.......................... 53 San Joaquin Valley and Sierra Nevada ...................................................................................................... 54 Older Pleistocene (>25,000 cal BP) ...................................................................................................... 54 Late Pleistocene (~25,000 to 15,000 cal BP)......................................................................................... 62 Latest Pleistocene (15,000 to 11,500 cal BP) ........................................................................................ 65 Early Holocene (11,500 to 7000 cal BP) .............................................................................................. 69 Middle Holocene (7000 to 4000 cal BP).............................................................................................. 75 Late Holocene (4000 to 2000 cal BP)................................................................................................... 79 Latest Holocene (2000 to 150 cal BP) .................................................................................................. 83 Historical to Modern (150 to 0 cal BP) ................................................................................................ 85 Great Basin and Mojave Desert ................................................................................................................ 89 Late Pleistocene and Older (>15,000 cal BP)........................................................................................ 89 Latest Pleistocene (15,000 to 11,500 cal BP) ........................................................................................ 89 Early Holocene (11,500 to 7000 cal BP) .............................................................................................. 91 Middle Holocene (7000 to 4000 cal BP).............................................................................................. 98 Late Holocene (4000 to 2000 cal BP)................................................................................................. 101 Latest Holocene (2000 to 150 cal BP) ................................................................................................ 102 Historic-Era to Modern (150 to 0 cal BP) .......................................................................................... 107 Summary and Discussion ....................................................................................................................... 110 Latest Pleistocene ............................................................................................................................... 110 Early Holocene................................................................................................................................... 110 Middle Holocene ............................................................................................................................... 113 Late Holocene .................................................................................................................................... 113 Latest Holocene.................................................................................................................................. 113 Conclusion............................................................................................................................................. 114 CHAPTER 5. ARCHAEOLOGY IN AN ACTIVE VOLCANIC REGION........................................... 117 Volcanism in South-Central California .................................................................................................. 117 Latest Pleistocene (15,000-11,500 BP) ............................................................................................... 118 Early Holocene (11,500-7000 BP) ..................................................................................................... 118 Middle Holocene (7000-4000 BP) ..................................................................................................... 122 Late Holocene (4000-2000 BP).......................................................................................................... 124 Latest Holocene (2000-150 BP) ......................................................................................................... 124 Implications for Human Occupation and Preservation of the Archaeological Record ......................... 125 The Prehistoric Use of Obsidian in South-Central California: Temporal and Spatial Aspects ................. 125 The Timing of Obsidian Use in South-Central California.................................................................. 127 The Holocene Distribution of Obsidian in South-Central California ................................................. 130 Conclusions ........................................................................................................................................... 132 454
Transportation Enhancement Activities Program iii Far Western California Department of Transportation, District 6/9
Geoarchaeological Study
CHAPTER 6. BURIED SITE POTENTIAL IN DISTRICT 6/9.......................................................... 133 Mapping Strategy and Methods ............................................................................................................. 133 Radiocarbon Database........................................................................................................................ 133 Digital Soils Surveys ........................................................................................................................... 134 Limitations of the Soils Surveys .......................................................................................................... 135 Map Development ............................................................................................................................. 138 Landform Map Limitations ................................................................................................................ 138 Landform Age and Buried Site Potential ................................................................................................ 139 Caltrans Right-of-Way ....................................................................................................................... 139 Environmental Parameters and Buried Site Potential.............................................................................. 140 Distance to Water Sources and Degree of Slope ................................................................................. 141 An Environmental Model of Buried Site Potential.................................................................................. 141 Comparison of Buried Site Potential Using Landform Age and Environmental Parameters ................ 142 Caltrans Right-of-Way ....................................................................................................................... 145 Estimating Buried Site Potential: Limitations, Performance, and Use..................................................... 146 Limitations of Environmental Parameters........................................................................................... 146 Testing the Landform Map and Environmental Model ...................................................................... 149 CHAPTER 7. APPROACHES FOR IDENTIFYING AND SAMPLING BURIED SITES .................. 153 Survey Strategies and Sampling Methods................................................................................................ 153 Phase I Survey .................................................................................................................................... 153 Phase I Extended “Subsurface” Survey................................................................................................ 154 Phase II Test Evaluation and Phase III Data Recovery........................................................................ 156 Using the Buried Site Potential Model ................................................................................................... 157 REFERENCES CITED.......................................................................................................................... 159

APPENDICES
Included on CD Inside Back Cover
Appendix A. Radiocarbon Dates Documenting Tulare Lake Level History.

Appendix B. Radiocarbon Dating Methods, Results, and Database.

Appendix C. Soil Types, Age Assignments, and Definitions for Soil Horizons and Layers.

Appendix D. Obsidian Hydration Methods, Results, and Database.

Appendix E. Extent of Buried Site Potential along each State Route in District 6/9 Based on Landform Map and Predictive Model.

Appendix F. Known Buried Prehistoric Archaeological Sites in Caltrans District 6/9.

Appendix G. Quaternary Geology Map and Buried Site Potential Map for District 6/9. (Also included as fold-out maps in back pockets.)
455
Far Western iv Transportation Enhancement Activities Program California Department of Transportation, District 6/9
Geoarchaeological Study

LIST OF FIGURES
Figure 1. Project Area..................................................................................................................................... 2 Figure 2. Location and Extent of Major Rivers and Streams in the Study Area. .............................................. 8 Figure 3. Koppen Climate Zones within District 6/9. .................................................................................. 14 Figure 4. Distribution of Annual Precipitation in District 6/9...................................................................... 15 Figure 5. Average Extent of Latest Pleistocene and Holocene Glacial Advances. ........................................... 21 Figure 6. Paleoconnections along the Owens River Drainage System............................................................ 23 Figure 7. Owens to China to Searles Proxy Lake Indicators.......................................................................... 26 Figure 8. Tulare Lake Highstands and Inferred Shorelines............................................................................ 29 Figure 9. Lake Level History of Tulare Basin................................................................................................ 30 Figure 10. Major Geomorphic and Stratigraphic Units in Western San Joaquin Valley. ............................... 37 Figure 11. Schematic Cross Section of Major Stratigraphic Units in the San Joaquin Valley......................... 38 Figure 12. Schematic Cross Sections of Merced River Showing Relation of Soils to Geomorphic Surfaces and Stratigraphic Units.......................................................................................................................... 40 Figure 13. Distribution of Radiocarbon Sample Localities in and near District 6/9. ..................................... 45 Figure 14. Pleistocene Radiocarbon Dates from Buried “Modesto-Age” Soils in the San Joaquin Valley....... 47 Figure 15. New Radiocarbon-Age Relationships of “Modesto” and Post-Modesto Soils in the Study Area. .. 48 Figure 16. Net Annual Sediment Yield in Relation to Precipitation.............................................................. 52 Figure 17. Depositional Landforms and Buried Archaeological Potential in Caltrans District 6/9. ............... 59 Figure 18. Older Pleistocene Fans Emanating from Glaciated and Unglaciated Drainages along the Eastern San Joaquin Valley. ................................................................................................................... 61 Figure 19. Selected Views of Older Pleistocene Deposits in the San Joaquin Valley...................................... 63 Figure 20. Selected Views of Late Pleistocene Deposits in the San Joaquin Valley. ....................................... 64 Figure 21. Late Pleistocene Fan and Basin Deposits in the Eastern San Joaquin Valley................................. 66 Figure 22. Latest Pleistocene Fan and Basin Deposits in the Western (top) and Eastern (bottom) San Joaquin Valley................................................................................................................................. 67 Figure 23. Selected Views of Radiocarbon-Dated Latest Pleistocene Deposits in the San Joaquin Valley. ..... 68 Figure 24. Count and Percent of Buried and Surface Natural (top) and Cultural (bottom) Contexts by Major Time Periods............................................................................................................................... 70 Figure 25. Early Holocene Fan and Basin Deposits in the Eastern San Joaquin Valley.................................. 72 Figure 26. Age and Frequency of Radiocarbon Dates from Buried Soils Associated with Natural and Cultural Contexts in District 6/9........................................................................................................... 73 Figure 27. Selected Views of Radiocarbon-Dated Early Holocene Deposits in the San Joaquin Valley.......... 74 Figure 28. Selected Views of Radiocarbon-Dated Middle Holocene Deposits in the San Joaquin Valley. ..... 76 Figure 29. Middle Holocene Fan and Basin Deposits in the Western (top) and Eastern (bottom) San Joaquin Valley................................................................................................................................. 78 Figure 30. Late Holocene Fan and Basin Deposits in the Western San Joaquin Valley. ................................ 80 Figure 31. Selected Views of Radiocarbon-Dated Late Holocene Deposits in the San Joaquin Valley........... 81 Figure 32. Selected Views of Radiocarbon-Dated Latest Holocene and Historic to Modern Deposits in the San Joaquin Valley....................................................................................................................... 84 Figure 33. Latest Holocene Fan and Basin Deposits in the San Joaquin Valley............................................. 86 456
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Figure 34. Examples of Historic-era Land Use and Landscape Changes in the San Joaquin Valley and Adjoining Portions of District 6/9. ........................................................................................................ 87 Figure 35. Historical to Modern Deposits in the San Joaquin Valley............................................................ 88 Figure 36. Older Pleistocene Fans Emanating from Glaciated and Unglaciated Drainages in the Owens Valley......................................................................................................................................... 90 Figure 37. Late Pleistocene Deposits in the Owens Valley (top) and Mojave Desert (bottom). ..................... 92 Figure 38. Selected Views of Latest Pleistocene Deposits in the Mojave Desert (top) and Owens Valley (bottom)................................................................................................................................................ 93 Figure 39. Freshwater Shell from Owens and Mojave River Systems (top) and Comparison of Dates from Shell and Other Lacustrine Sources (bottom). ............................................................................... 95 Figure 40. Early Holocene Deposits in the Owens Valley............................................................................. 96 Figure 41. Selected Views of Radiocarbon-Dated Early Holocene Deposits in Owens and Indian Wells Valleys. .................................................................................................................................................. 97 Figure 42. Middle Holocene Fan and Basin Deposits in Rose Valley (top) and Owens Valley (bottom). ...... 99 Figure 43. Selected Views of Middle Holocene Fan and Basin Deposits in Indian Wells, Rose, and Mono Valleys. ..................................................................................................................................... 100 Figure 44. Selected Views of Late and Latest Holocene Deposits in Deep Springs, Fremont, Little Lake, and Owens Valleys............................................................................................................................... 103 Figure 45. Late Holocene Deposits in the Upper Owens Valley (top) and Lower Owens Valley (bottom).. 104 Figure 46. Latest Holocene Deposits in Antelope and Fremont Valleys. ..................................................... 106 Figure 47. Historical to Modern Deposits in the Owens Valley (above) and Antelope Valley (below)......... 108 Figure 48. Historic-era Land Use and Landscape Changes in the Great Basin and Northern Mojave Desert in Portions of District 6/9. ........................................................................... 109 Figure 49. Comparison of Radiocarbon Dates from Buried Soils by Physiographic Region In and near District 6/9.......................................................................................................................................... 111 Figure 50. Comparison of Radiocarbon-Dated Surface and Buried Contexts from Eastern and Western Regions of District 6/9. ....................................................................................................................... 115 Figure 51. Radiometric (top) and Radiocarbon (bottom) Dates Associated with Volcanic Deposits in the Mono-Inyo Chain. .............................................................................................................................. 119 Figure 52. Distribution of Holocene Volcanic Deposits in the Mono-Inyo Craters Area. ........................... 120 Figure 53. Holocene-Age Volcanic Deposit in the San Joaquin Valley........................................................ 121 Figure 54. Radiocarbon-Dated Holocene-age Volcanic Strata in the Study Area. ....................................... 123 Figure 55. Percentage of Radiocarbon Dates from Surface and Buried Volcanic Contexts. ......................... 126 Figure 56. Obsidian Hydration Profiles for Main Sources Utilized in the Study Area................................. 129 Figure 57. Distribution of the Three Primary Obsidian Types found in Archaeological Contexts within District 6/9............................................................................................................................... 131 Figure 58. Mapping Discrepancies within SSURGO soil data (top) and between SSURGO and STATSGO soils data (bottom). ........................................................................................................... 136 Figure 59. Extent of Buried Site Potential Based on the Landform Map Compared to the Predictive Model. ................................................................................................................................ 144 Figure 60. Buried Site Potential Model for District 6/9 with Distribution of Known Buried Sites.............. 147 Figure 61. Predicted Potential for Buried Sites at Actual Buried Sites (observed) Compared to Random Sample of Sites in District 6/9............................................................................................... 152 Figure 62. Comparison of the Age and Depth of Buried Natural and Cultural Contexts. ........................... 155 457
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LIST OF TABLES
Table 1. Radiocarbon Dates from Late Pleistocene Glacial Moraines in the Sierra Nevada. .......................... 19 Table 2. Generalized Sierra Nevada Glacial Sequence................................................................................... 20 Table 3. Previous Correlations of Glacial and Stratigraphic Sequences in Central California and Adjacent Areas. ...................................................................................................................................... 33 Table 4. Relationship of Glacial Stages with Deposits in the San Joaquin Valley and Adjoining Foothills..... 36 Table 5. Summary of Proposed Age Ranges for Upper Modesto and Post-Modesto Deposits....................... 36 Table 6. Summary of Soil Types Previously Associated with Modesto and Post-Modesto Deposits. ............. 41 Table 7. Previous and Revised Age of Surface Soils Associated with “Modesto” and “Post-Modesto” Deposits in the San Joaquin Valley. ....................................................................................................... 49 Table 8. Summary of Radiocarbon Dates Obtained for This Study (Listed by Lab/Sample Number)........... 55 Table 9. Summary of Radiocarbon-Dated Buried Soils from Study Area by Time Periods............................ 62 Table 10. Identified Deposits of Tsoyowata and Mazama Tephra in Northeastern California. ................... 122 Table 11. Obsidian Hydration Summary Information for Latest Pleistocene and Early Holocene Artifacts by Source............................................................................................................................... 128 Table 12. Obsidian Hydration Summary for Latest Pleistocene and Early Holocene Artifacts by Region and Source............................................................................................................................... 128 Table 13. Summary of Radiocarbon Database............................................................................................ 133 Table 14. Summary of Radiocarbon Database by Time Interval and Context............................................. 134 Table 15. Summary of Digital Soil Survey Data and Coverage. .................................................................. 135 Table 16. Definitions of Landform Map Units........................................................................................... 137 Table 17. Age and Buried Site Potential of Depositional Landforms in the Sierra Nevada (adapted from Meyer and Rosenthal 2008).......................................................................................... 138 Table 18. Buried Site Potential and Size of Landform Map Units in the Study Area. ................................. 140 Table 19. Parameters Used to Model Slope and Distance to Water. ........................................................... 141 Table 20. Buried Site Potential Scoring System and Possible Score Combinations...................................... 142 Table 21. Comparison Buried Site Potential Scores, and Area Covered. ..................................................... 142 Table 22. Buried Site Potential and Area Covered by Landform Map Units............................................... 143 Table 23. Buried Site Potential of Landform Map Compared to Environmental Parameters along all Roadways in District 6/9. ...................................................................................................... 145 Table 24. Roadways with the Greatest Linear Extent of Reduced or Elevated Buried Site Potential Based on Environmental Parameters.............................................................................................................. 146 Table 25. Buried Site Potential Identified by Environmental Model at Known Buried Sites....................... 150 Table 26. Predicted Buried Site Potential at Actual Buried Sites Compared to Random Sample................. 151 Table 27. Depth of Buried Radiocarbon Samples by Time Period.............................................................. 156 Table 28. Suggested Actions and Level of Effort for Zones of Buried Site Potential.................................... 158 458
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CHAPTER 1. INTRODUCTION
The California Department of Transportation (Caltrans) is conducting a cultural resources inventory of rural roads in Districts 6 and 9 (hereafter District 6/9), which includes the counties of Madera, Fresno, Kings, Tulare, Kern, Mono, and Inyo (Figure 1). The inventory combines survey for prehistoric and historic-period archaeological sites, historic-period structures, and architectural properties, along with Native American consultations and ethnographic studies (Davis-King et al. 2009; Leach-Palm et al. 2009a, 2009b; Milliken et al. 2010). In addition, the following geoarchaeological investigation was implemented as part of the inventory to provide Caltrans with baseline information on the potential for buried archaeological resources along rural road segments. This is the third in a series of geoarchaeological investigations conducted for Caltrans designed to address the relationship between late Quaternary landscape evolution and the structure and visibility of the archaeological record. The previous two studies focused on districts 3 and 10 which include the southern Sacramento Valley, northern San Joaquin Valley, and adjacent portions of the eastern Coast Ranges and western Sierra Nevada (Meyer and Rosenthal 2008; Rosenthal and Meyer 2004b). A more geographically restricted study was also completed for the southern Santa Clara Valley (Rosenthal and Meyer 2004a).

The seven counties of Caltrans District 6/9 encompass a diverse landscape, extending eastward from the Diablo and Temblor ranges, across the San Joaquin Valley and Sierra Nevada, to the southwestern Great Basin and northern Mojave Desert (Figure 1). Included within the study area are Mt. Whitney and Death Valley, the highest (4,421 meters [14,505 feet] above sea level) and lowest (86 meters [282 feet] below sea level) points, respectively, in the contiguous United States. Over the span of human occupation in the new world, roughly the past 15,000 years, this landscape has changed dramatically, providing a dynamic backdrop for human colonization, social development, and economic change. In response to world-wide fluctuations in climate, massive glaciers that once occupied the highest peaks of the Sierra Nevada receded, extensive river and lake systems east and west of the Sierra Nevada declined and often dried, 35 genera of mammals including the largest ice-age herbivores became extinct (Grayson 1993), and repeated cycles of erosion and deposition sculpted and transformed the landscape. Such extensive changes not only affected the ways in which humans interacted with the environment, but also how and where evidence of past human occupation is preserved in the modern landscape.

The current study begins with the premise that the archaeological record is inherently biased by processes of landscape evolution. Older archaeological deposits are frequently under-represented at the surface of the modern landscape due to cyclical periods of erosion and deposition during the Holocene (<11,500 cal BP). This is particularly true in the southern San Joaquin Valley and basins east of the Sierra Nevada where substantial alluvial fans and floodplains developed episodically during the span of human occupation. Yet the region also has among the highest concentrations of surface archaeological deposits in California dating to the late Pleistocene and early Holocene. The presence of these ancient surface sites attests to the temporal mosaic that is the modern geomorphic landscape.

With this in mind, a primary goal of the current study was to establish the age and depositional history of late Pleistocene landforms (<25,000 years old) within the seven counties of Caltrans District 6/9.

Understanding the age of different landforms is first-order geochronology (Butzer 1980; Renfrew 1976; Waters 1992), a fundamental step in discerning where the archaeological record is likely to be buried, and where cultural remains deposited over the entire span of human occupation may be preserved on or just below the modern ground surface. By mapping the age of surface landforms, we are able to make an initial assessment of the potential for buried archaeological resources throughout a large segment of south-central California, from the eastern foothills of the Coast Ranges to the valleys of the western Great Basin and northern Mojave Desert, providing baseline information on the age of associated archaeological sites. Maps and descriptions of Holocene landscape evolution generated by this study should supplement surface surveys and provide additional contextual information that can be used by resource managers to make decisions about the need for subsurface reconnaissance in particular project areas.
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METHODS
Although large portions of the California landscape were emplaced long before humans entered North America, numerous recent studies have shown that repeated cycles of erosion, deposition, and landscape stability have occurred during the latest Pleistocene and Holocene (e.g., Allen et al. 1999; Bacon et al. 2003; Benson et al. 1997; Meyer 1996; Meyer and Rosenthal 1997, 2008; Rosenthal and Meyer 2004a, 2004b; Shlemon and Begg 1975; Wells et al. 2003; White 2003; Young 2009). As a result of these cyclical processes, buried archaeological deposits are not distributed randomly, but are confined to those portions of the landscape that developed during the span of human occupation (i.e., roughly the last 15,000 years; e.g., Goebel et al. 2008; Waters and Stafford 2007). Segments of the surface landscape that developed prior to human colonization of North America obviously cannot contain buried archaeological deposits (Rosenthal and Meyer 2004a, 2004b). With this basic understanding, the search for buried portions of the archaeological record in District 6/9 can be narrowed to recent landform segments, allowing extensive, older portions of the landscape to be confidently excluded from consideration.

To identify the age and extent of different landform segments within the study area, we relied heavily on the recently compiled Soil Survey Geographic Database (SSURGO) and the State Soils Geographic database (STATSGO). Because soil formation is a by-product of sustained or prolonged landscape stability, the degree of soil development is directly related to the amount of time a landform has been subjected to near-surface weathering processes. Landforms with well-developed soils have been stable longer than those with weakly or moderately developed soils. Using these characteristics of soil development we are able to group soil types and landform segments with similar weathering profiles into larger chronostratigraphic units within the SSURGO and STATSGO databases. The age of different soil series and their associated landforms are further refined through the compilation of contextual information for more than 2,400 previously reported radiocarbon dates, analysis of landform superposition, field examination of stratigraphic relationships, and targeted radiocarbon dating for this study. From this work, we produced a detailed map of latest Pleistocene, Holocene, and Historical landforms in District 6/9 (presented in Chapter 5). The age of these landforms serves as a basis for determining their potential to contain buried archaeological deposits and allows for an initial assessment of the relationship between archaeological sites of different ages and the timing of landscape evolution in western California, the southwestern Great Basin, and northwestern Mojave Desert.

Compensating for secular variations in the cosmic output of radiocarbon over time, all radiocarbon dates used in this report (unless otherwise indicated) were calibrated to calendar (solar) years before present (cal BP).

Radiocarbon dates less than about 22,000 14C BP were adjusted using the CALIB version 5.1 program in accordance with Stuiver and Reimer (1993); zero years before present (0 BP) equals 1950 AD by convention.

Dates greater than about 22,000 14C BP were calibrated in accordance with Fairbanks et al. (2005) using an online computer program. Regional correction factors were applied to all dates from marine and freshwater shell to compensate for the reservoir effects of old or dead carbon (Berger and Meek 1992; Culleton 2006). The exception is small freshwater gastropods which do not require such corrections (Pigati 2002; Pigati et al. 2004).

Unless otherwise indicated, single dates are reported as the calculated median probability, and the error ranges are reported at the 2-sigma (95%) confidence level, and are identified by their original lab number.

RESEARCH AGENDA
According to Waters (1992:7-11), modern geoarchaeological research has three main objectives: (1) place archaeological deposits in their temporal and stratigraphic context; (2) understand the natural processes of site formation; and (3) reconstruct the paleo-landscape. Given the scale of the current study—covering much of south-central California—we apply this geoarchaeological agenda in the broadest sense.

Because we are primarily concerned with the relationship between region-wide patterns of landscape evolution and its affect on the structure and visibility of the archaeological record, discerning the nature, timing, and extent of landscape change is a two-fold problem. It requires not only consideration of the outcome of geomorphic processes (i.e., deposition, stability, erosion), but also the environmental mechanisms responsible for those processes.
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Climatically Induced Landscape Change
Long-standing models of late Quaternary landscape evolution, particularly in western California (i.e., west of the Sierra Nevada), assume a direct relationship between climatically driven glacial cycles and episodic development of nested alluvial fans at the base of the Sierra Nevada (Atwater et al. 1986; Dupre et al. 1991; Marchand and Allwardt 1981; Harden and Marchand 1980). Although these models have been regularly invoked to explain and date fan sequences throughout much of central California, they remain largely untested. Less than a handful of radiocarbon dates from widely separated localities has been used to support original suppositions about the timing of fan development and mechanisms responsible for deposition on the western slope of the Sierra Nevada. As a result, the relationships between the timing of glacial advance and recession, and fan aggradation and incision have never been clearly defined or demonstrated.

On the eastern flank of the Sierra Nevada, no well-substantiated fan chronology currently exists, leaving a potentially important record of late Pleistocene and Holocene landscape evolution undefined. Resolution of this record will ultimately be important for understanding the relationship between glacial cycles and the mechanisms and timing of landscape change in the Owens Valley, Mono Basin, and Bridgeport Valley. Away from glaciated watersheds in the Great Basin and Mojave Desert, alluvial deposition has been treated more idiosyncratically, primarily interpreted as a response to local geomorphic thresholds. However, even in isolated basins, it is probable that large-scale environmental fluctuations would have triggered a geomorphic response discernable in the modern landscape.

Pleistocene-Holocene Environmental Change and Human Land Use Paleoclimatic changes that affected resource distributions would have had a strong influence on native subsistence economies and, in turn, settlement locations, ultimately influencing where archaeological deposits from different time periods are preserved in the modern landscape. The extensive system of interconnected lakes and rivers that unified a large portion of the southwestern Great Basin and northern Mojave Desert during the late Pleistocene was on the decline when humans first entered this region. The value of lakeside and riparian ecosystems to early subsistence economies is attested to by the high density of latest Pleistocene and early Holocene human settlements associated with now-dry lake beds and river channels, both east and west of the Sierra Nevada. However, many of the earliest sites in these lake basins are found well below the elevation of late Pleistocene lake stands, suggesting that human occupation occurred at a time when pluvial lakes were desiccated, or in a recessional phase.

The relationship between early human occupation and now-dry lake basins, particularly in the Mojave Desert, has a long history of archaeological research, yet we continue to know very little about the composition of subsistence economies during this time period and the specific resources that made lake basins attractive to late Pleistocene and early Holocene foragers throughout the Great Basin, Mojave Desert, and San Joaquin Valley.

Likewise, how early foraging groups accommodated end-Pleistocene and early Holocene shifts in biotic productivity remains poorly resolved. We cannot begin to fully understand the nature of these early subsistence economies until well-preserved assemblages of associated dietary debris are discovered, and these will only occur in buried stratigraphic contexts, making the search for such deposits paramount.

Archaeology in an Active Volcanic Region
The Inyo-Mono volcanic chain is one of the most active volcanic regions in North America. Numerous volcanic eruptions have occurred in this part of eastern California during the latest Pleistocene and Holocene, with potentially devastating effects to human foraging groups and the primary plant and animal foods from which they made their living (e.g., Hall 1983). These eruptive events spewed tons of volcanic ash and pumice across a significant portion of the study area, obscuring many older archaeological deposits and producing important stratigraphic signatures identified in lake sediments and alluvial landforms east and west of the Sierra Nevada.

Furthermore, the distribution of ejected debris has important implications for the efficacy of standard archaeological survey, particularly in Long Valley, Mono Basin, and adjacent lowlands.

The Inyo-Mono region also contains some of the most important prehistoric obsidian quarries in the far west. For at least 13,000 years this material has been quarried and moved by people throughout the Great Basin 462
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and Mojave Desert and across the Sierra Nevada into central California. The distribution of different obsidian sources provides important information useful in reconstructing past foraging territories, changing social relations, and exchange networks across a large portion of south-central California. To the extent that obsidian was an integral part of prehistoric technologies in eastern California, the geographic distribution of obsidian quarries is also thought to have been a factor influencing land use and mobility at different times in the past.

Filling the Middle Holocene Gap
Both east and west of the Sierra Nevada, the record of middle Holocene (ca. 7000 to 4000 cal BP) human occupation remains difficult to find, vastly underrepresented compared to sites from the late Holocene. In both regions, declines in effective precipitation during the middle Holocene are thought to have had structural effects on prehistoric economies and influenced changes in land use, potentially resulting in wholesale abandonment of arid regions (e.g., Elston 1982; Grayson 1993). The extent to which environmental changes actually affected human populations is an on-going problem for archaeologists. The apparent dearth of middle Holocene and earlier sites may in part be related to extensive landscape changes during the late Holocene, obscuring these older deposits, particularly in well-watered settings such as the Owens Valley and San Joaquin Valley.

STRUCTURE OF THE REPORT
We address these research concerns in the following chapters, beginning with an overview of the physiography and climate of the Study Area (Chapter 1), both of which had a strong influence on the nature of landscape evolution in south-central California. Chapter 2 begins with an overview of late Pleistocene and Holocene glacial cycles in the Sierra Nevada and a discussion of pluvial lakes in both eastern and western California, critical background for understanding existing models of landscape change in the Study Area. The second part of Chapter 2 examines the glacial model of landscape evolution, focusing on discrepancies between glacial cycles and alluvial fan and floodplain development in central California. Chapter 3 begins with a new model of landscape evolution based on region-wide changes in climate. A climate change model better accounts for cyclical landscape responses identified in both glaciated and unglaciated drainages and throughout the Holocene, when glacial mechanisms would have been inconsequential.

Next, more than 2,000 radiocarbon dates are used to redefine the depositional history of major landform segments in District 6/9. The Study Area’s chronostratigraphy serves as a foundation for regional modeling of landscape change and a basis for the map of buried site potential ultimately presented. Chapter 4 provides an overview of the Holocene eruptive history of the Inyo-Mono volcanic chain, identifies the timing and geographic extent of a series of Holocene ash-falls affecting the eastern and western Sierra Nevada, and tracks the earliest use and geographic distribution of obsidian from several important prehistoric quarries located in the Study Area.

Chapter 6 provides an assessment of buried site potential throughout District 6/9 based on the distribution of Holocene-age landforms and a simple model of human settlement. Particular attention is paid to Caltrans highway alignments, documenting the buried site potential of each rural road segment. The final chapter (Chapter 7) outlines methodological approaches for identifying and sampling buried archaeological sites. 463
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CHAPTER 2. ENVIRONMENTAL SETTING
Caltrans District 6/9, also referred to as the Study Area, is located in south-central California and encompass nearly 35,922 square miles, close to one-quarter of the modern state. District 6 falls almost entirely west of the Sierra Nevada crest, and includes the counties of Madera, Fresno, Kings, Tulare, and Kern. Only a portion of eastern Kern County extends across the Sierra Nevada and Tehachapi Range into eastern California.

All of District 9, which includes the counties of Inyo and Mono, lies east of the Sierra Nevada crest.

Varied relief and physiography across the districts create significant differences in temperature and precipitation from west to east and from north to south. These environmental differences had a direct bearing on past distributions of economically important plant and animal foods, which in turn influenced prehistoric human settlement-subsistence strategies and land-use patterns. Likewise, these factors contributed to the nature and extent of landscape evolution, as well as the context, preservation, and location of archaeological deposits from different time periods.

With these relationships in mind, the current chapter begins with an overview of the Study Area’s physical geography, providing descriptions of major mountain ranges, valley systems, and hydrologic patterns.

Then we examine the region’s diverse climate, focusing on the ways in which topography and weather patterns interact to affect temperature and precipitation.

PHYSICAL GEOGRAPHY AND HYDROLOGY
The Study Area cross-cuts five major geomorphic provinces, including portions of the Coast Ranges, Central Valley, Sierra Nevada, Basin and Range, and Mojave Desert. Elevations range from 4,421 meters (14,494 feet) above mean sea level1
at Mt Whitney to 86 meters (282 feet) below sea level at Death Valley, attesting to the marked topographic relief which characterizes the Study Area. With the exception of the Transverse Ranges, all major mountain chains are oriented roughly northwest to southeast, creating a series of parallel valley systems.

The Sierra Nevada is the most prominent mountain range in California and serves as a natural divide between western California and the Great Basin and Mojave Desert to the east. California’s Coastal Range lies along the western border of the Study Area, separated from the Sierra Nevada by the San Joaquin Valley. Owens Valley lies between the steep escarpment of the eastern Sierra Nevada and the White and Inyo mountains, while further east, Panamint Valley and Death Valley are flanked by the Panamint and Armagosa ranges, respectively.

Several other smaller mountain ranges and internally drained valleys fall within the Great Basin and Mojave Desert portions of the Study Area, adding to their topographic heterogeneity and hydrologic complexity (Figure 2).

Coast Ranges
The foothills of the Diablo Range (a portion of California’s Coast Ranges) form the western boundary of the Study Area in Madera, Fresno, and Kings counties, while the Temblor Range forms the western border in Kern County. Rising more than 915 meters (3,000 feet) above the San Joaquin Valley, the eastern margin of the Diablo Range is composed of uplifted Cretaceous-age marine sandstone, siltstone, shale, and conglomerate of the Great Valley sequence (Jennings 1977). Further west, the older Franciscan assemblage forms the core of the Coast Ranges and structurally occurs beneath rocks of the Great Valley sequence. The Franciscan formation consists mainly of bedded deposits of greywacke and shale divided by a discontinuous mélange of greenstone, greywacke, gabbro, serpentinite, and red and green radiolarian chert. Metamorphism of the Franciscan assemblage has also resulted in the development of metagraywacke, metachert, actinolite schist, and glaucophane schist. These rocks outcrop widely throughout the central part of the range, and frequently occur as secondary alluvial deposits and as bed-load in modern stream channels exiting the coastal range into the San Joaquin Valley.

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Numerous streams bisect the foothills of the Diablo Range west to east, carving relatively deep, terraced canyons that connect small interior valleys with the San Joaquin Valley. Among the major drainages are, from north to south, Little Panoche Creek, Panoche Creek, Tumey Gulch, Arroyo Hondo, Cantua Creek, Salt Creek, Los Gatos Creek, Jacalitos Creek, and Zapato Chino Creek. Where these streams exit the Diablo Range, they have built relatively steep alluvial fans that coalesce to form a narrow piedmont along the entire mountain front.

The eastern Diablo Range does not typically provide enough water to maintain continuous year-round flows, and most drainage systems are completely dry by mid-summer. Even when sufficient water is present between December and May, few if any of these drainages actually reach the axial San Joaquin River, dissipating instead into porous alluvial deposits along the valley margins (Lettis 1985).

To the south, the Temblor Range is divided from the main body of the Coast Range by the San Andreas Fault which extends in a northwest-southeast direction forming the Chalome Creek drainage. The Temblor Range is also younger than its northern counter-part, consisting of uplifted Miocene marine sandstone, shale, siltstone, conglomerate, and breccia. It is separated from the main San Joaquin Valley by a series of low, northwest-trending ridges and valleys formed by neo-tectonic activity along the San Andreas Fault. These ridges are composed of loosely consolidated continental sedimentary deposits of Pliocene- and Pleistocene-age sandstone, shale, and gravel, including the Kettleman Hills, Lost Hills, and Elk Hills (Jennings 1977). In-between the main body of the Diablo Range and the Temblor Range lie Antelope Valley and the Antelope Plain.

Bitterwater Creek, Chico Martinez Creek, Salt Creek, and Buena Vista Creek are the main drainages exiting the Temblor Range en-route to the basins of the southern San Joaquin Valley. Like streams to the north, those exiting the Temblor Range seldom maintain surface flows, remaining dry throughout a large portion of the year.

Tehachapi Mountains and Transverse Ranges
The Tehachapi Mountains form the southern boundary of the San Joaquin Valley and are the northernmost of the transverse ranges, rising to an elevation over 2,410 meters (7,900 feet) at Double Mountain.

The main body of the Transverse Ranges, which lie south of the current Study Area, run perpendicular to virtually all other mountain and valley systems in California. They were formed as a result of a bend in the San Andreas Fault, causing compressional uplift where the Pacific Plate moves in a westward direction against the North American Plate. The Tehachapi Mountains link the Coast Ranges with the southern Sierra Nevada and also separate western California from the Mojave Desert and Great Basin to the south and east. They are underlain by granitic rocks of the Sierran batholith and were developed as a result of movement along the Garlock Fault which runs along the southern flanks of the range. The San Emigdio Mountains lie immediately to the northwest of the Tehachapis along the southwestern margin of the San Joaquin Valley. These mountains are a southern extension of the Coast Range as indicated by their similar lithologies, mainly of Tertiary, sandstone, shale, siltstone, conglomerate and breccia (Jennings 1977).

A series of minor streams exit the northern slopes of the Tehachapi and San Emigdio mountains flowing northward into Buena Vista and Kern basins. From west to east these include Bitter Creek, Santiago Creek, Los Lobos Creek, San Emigdio Creek, Pleito Creek, Salt Creek, Tecuy Creek, Pastoria Creek, Tunis Creek, El Paso Creek, Tejon Creek, Comanche Creek, and Caliente Creek. Those drainages on the western side of the San Emigdio Range, such as Quatal Canyon and Alamo Creek, form the headwaters of the Cuyama River which drains westward through the Coast Range to the Pacific Ocean via the Santa Maria River. Like other drainages in this region, surface flows are rare, and most streams draining the Tehachapi and San Emigdio ranges remain dry most of the year.

San Joaquin Valley
The San Joaquin Valley segment of the Study Area begins on the north at the Madera-Merced and Fresno-Merced county lines. The valley is bound by the Diablo Range on the west, Tehachapi and San Emigdio Mountains on the south, and Sierra Nevada Mountains on the east. Included are portions of Madera, Fresno, Kings, Tulare, and Kern counties. The valley itself is an asymmetric structural trough, underlain by thick deposits of Quaternary alluvium eroded from the surrounding mountain fronts (Bartow 1991). Elevations on the valley floor gradually decline northward from about 105 meters (345 feet) at Greenfield near the base of the Tehachapis, 467
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to about 33 meters (108 feet) near the Fresno, Madera, and Merced county lines. Expansive, low-gradient alluvial fans form a broad piedmont on the eastern side of the valley bordering the Sierra Nevada, while on the western side, coalesced fans originating from the Coast Range are comparatively short and steep. This configuration has caused the axial San Joaquin River to be offset towards the west, directed away from the valley center by the massive alluvial deposits fringing the Sierra Nevada.

The northern San Joaquin Valley is separated from Tulare Basin to the south by a subtle hydrological divide formed by the Kings River fan on the east and the Los Gatos Creek fan on the west. Throughout the historic-era, the Kings River spilled southward through a series distributary channels in its broad deltaic fan, providing about 50% of the water input to Tulare Basin and Tulare Lake (Atwater et al. 1986). In the past, Tulare Lake would periodically overtop the Kings River fan at an elevation of approximately 64 meters (211 feet) (Grunsky 1898a:61) and flow northward into the San Joaquin Valley through a forty-mile-long incision known as Fresno Slough. Near the modern town of Mendota, at an elevation of about 50 meters (160 feet), Fresno Slough merges with the San Joaquin River. Here the river is highly sinuous, branching into a mosaic of sloughs and side channels that diverge from both sides of the main channel. It continues in this manner northward to the Merced County line where it exits the Study Area.

South of the Kings River fan, impounded flows of the Kings, Kaweah, and Tule rivers created Tulare Lake, once the largest body of water west of the Great Lakes (Davis 1999a). Due to historic-period diversion of its main water source (the Kings River), Tulare Lake now stands dry. Historically the lake fluctuated in size from a few square miles during extremely dry years to as much as 800 square miles during wet years (Grusky 1898b:16).

Tulare Basin itself is divided into sub-basins by a broad alluvial fan emanating from the Kern River. Kern and Buena Vista lakes once occupied the extreme southern end of the valley and occasionally coalesced and spilled northward into Tulare Lake. Historically these southern lakes were fed mainly by outflow from the Kern River, but minor input also came from numerous seasonal drainages originating from the Tehachapis. Like Tulare Lake, Kern and Buena Vista lakes remain dry as a result of water diversion.

Sierra Nevada
The Sierra Nevada segment of the Study Area incorporates eastern portions of Madera, Fresno, Tulare, and Kern counties, as well as western portions of Mono and Inyo counties. This 640-kilometer- (400-mile-) long mountain range separates the San Joaquin Valley on the west from the Owens Valley and Mono Basin on the east. It is the single largest mountain system in the contiguous United States and varies between 50 and 80 miles wide (Hill 2006). Throughout its entire length, the Sierra Nevada is characterized by a long, gradual western slope and a short, abrupt eastern escarpment. In the current Study Area, the crest of the Sierra rises to elevations over 4,250 meters (14,000 feet) at Mt. Whitney, more than 3,050 meters (10,000 feet) above the Owens Valley floor just ten miles to the east. Numerous other peaks reach elevations above 3,650 meters (12,000 feet), making average elevations in the southern Sierra Nevada the highest along the range’s length.

Granitic rocks of the Sierran batholith dominate the eastern and western slopes of the mountain range.

Unlike the central Sierra to the north, where a heterogeneous mélange of metamorphic rocks occurs in a continuous expanse along the foothill fault zone, few rocks other than granite are widely exposed in the southern Sierra. The most prominent are isolated and discontinuous outcrops of pre-Cenozoic metasedimentary and metavolcanic materials, including mostly slate, quartzite, hornfels, chert, phyllite, mylonite, schist, gneiss, and marble (Jennings 1977).

Several major rivers drain the western slope of the southern Sierra Nevada, many originating from formerly glaciated headwaters, including the San Joaquin, Kings, Kaweah, and Kern rivers. These drainages have carved deep canyons through the Sierran granite, some as much as 2,440 meters (8,000 feet) deep (Hill 2006).

Smaller rivers and streams, such as the Fresno, Chowchilla, and Tule rivers, originate lower on the western slope, below the influence of the former glaciers, and their channels are not as deeply entrenched. Although most rivers in the Sierra assume a parallel course, bisecting the range from east to west, the Kern and upper San Joaquin rivers first travel along the axis of the range, south and north respectively, before turning westward to meet the San Joaquin Valley. Where the major rivers emerge from the western slope, they have built a nested series of massive 468
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alluvial fans which decrease in age basin-ward and often coalesce, creating a broad, low-gradient piedmont that fringes the entire western slope.

The only major drainage emerging from the eastern side of the Sierra is the Owens River. It originates above the southern Mono Basin and first flows eastward into Long Valley and then southward into Owens Valley. Due to the abrupt configuration of the eastern slope, numerous small streams emanate from the once glaciated crest of the Sierra, descending steep canyons en-route to Bridgeport Valley, Mono Basin, or Owens Valley below. Typically these drainages run perpendicular to the long axis of the mountain range and occur about every three to five miles, creating an alluvial apron of coalesced fans along the eastern base of the Sierra Nevada.

In Bridgeport Valley, at the northern end of the Study Area, all major streams merge with the East Walker River and flow eastward into western Nevada. To the south, the Mono Basin is internally drained, capturing surface flows from both the Sierra Nevada and Bodie Hills. The numerous drainages entering the Owens Valley from the eastern slope often dissipate in coarse-grained alluvial fans before reaching the axial Owens River. Further south, Sierran drainages become more widely spaced and only rarely contribute surface flows to the valleys of the northern Mojave Desert.

Great Basin
Falling entirely within Mono and Inyo counties, the Great Basin segment of the Study Area is bound by the Sierra Nevada on the west, the California-Nevada border on the east, and the Mono-Alpine county border on the north. For purposes of this discussion, Rose Valley forms the southern boundary of the Great Basin, lying as it does on the northern edge of the Mojave Desert.

North-south trending mountain ranges divide the Great Basin into a series of long, narrow valley systems that run parallel to the eastern escarpment of the Sierra Nevada. Only at the extreme northern end of the Study Area is this pattern broken by relatively recent volcanic ridges that create several small intermontane basins including Bridgeport Valley, Adobe Valley, Long Valley, and Mono Basin. Further south, the Owens Valley borders the eastern escarpment of the Sierra Nevada, extending more than 80 miles until reaching its southern end at Owens Lake. From there, Rose Valley continues southward between the granitic peaks of the high Sierra and the recent volcanic mountains of the Coso Range.

The eastern side of Owens Valley is defined by the White and Inyo mountains which reach more than 4,250 meters (14,000 feet) at White Mountain Peak. The mountain chain declines southward to its terminus at Cerro Gordo Peak, which stands at about 2,800 meters (9,200 feet) elevation, about 1,220 meters (4,000 feet) above the floor of Owens Lake. Broadly spaced drainages emerge from the western side of the White-Inyo range, producing a series of isolated alluvial cones that extend basin-ward from the bedrock slopes. Due to only minor alluvial input from these mountain fronts, Owens River has assumed a course along the eastern side of Owens Valley, influenced in that direction by the comparatively broad alluvial piedmont at the base of the Sierra Nevada (Hollett et al. 1991). Owens River is fed mainly by run-off from the eastern slope of the Sierra beginning with its headwaters west of Long Valley. The Owens River watershed also incorporates runoff from Benton, Hammill, and Chalfont valleys, located east of Long Valley and the volcanic tablelands.

On the eastern side of the White and Inyo mountains lie several internally drained basins including, from north to south, Deep Springs Valley, Eureka Valley, Saline Valley, and Panamint Valley. The Last Chance Range and Panamint Mountains divide these smaller basins from Death Valley which lies to the east. In turn, Death Valley is separated from the Armagosa Desert and Pahrump Valley in western Nevada by the Armagosa Range.

Mountain ranges in the western part of the Great Basin consist of various combinations of plutonic and volcanic rocks, while those to the east are formed from uplifted marine sedimentary and meta-sedimentary rocks.

The former include mainly granitoid and basaltic rocks, as well as localized deposits of obsidian, while the latter are composed of various cherts, slate, sandstone, limestone, dolomite, marble, phyllite, schist, hornfels, gneiss, and quartzite. Alluvial bajadas along valley margins incorporate secondary deposits of these rocks, particularly on older pediments where they are often exposed in continuous pavements.

With the exception of the Owens River and numerous smaller streams draining the eastern Sierra Nevada, surface water is rare in the Great Basin segment of the Study Area. Throughout this region, small springs 469
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provide the main sources of fresh water, supplemented occasionally by winter rainstorms which enliven dry washes and quench perennially dry playas. During the late Pleistocene, however, an inter-connected system of lakes and rivers once unified this region, fed by rainfall and snow melt from the Sierra Nevada and coastal Peninsular Ranges to the west. For the most part, however, only a small vestige of this once extensive river and lake system remains, consisting of the East Walker River, Mono Lake, Owens River, and Owens Lake, sustained by surface flows from the eastern slope of the Sierra.

Mojave Desert
The Mojave Desert portion of the Study Area is situated within the southeastern portion of Kern County and extreme southern end of Inyo County, incorporating portions of Indian Wells, Fremont, and Antelope valleys. The Tehachapi Mountains and Sierra Nevada define the northwestern boundary of the Mojave Desert province, while the San Bernardino and Los Angeles county lines demarcate the eastern and southern boundaries of the Study Area, respectively. The El Paso Mountains and Black Hills separate Indian Wells Valley to the north from Fremont Valley to the south, the latter separated from the Antelope Valley further south by the Rand Mountains, Rosamond Hills, and Bissel Hills. Each of the basins in the Mojave Study Area is distinguished by a valley-bottom playa, dry lakebeds that are enduring remnants of the regions more verdant past. These include the playas at China Lake in Indian Wells Valley, Koehn Lake in Fremont Valley, and Rogers, Buckhorn and Rosamond lakes in Antelope Valley.

Bedrock in the Mojave segment of the Study Area consists mainly of granite, quartz monzonite, granodiorite, and quartz diorite. Volcanic, metavolcanic, and metasedimentary rocks underlie the El Paso Mountains and Black Hills along the Garlock Fault, while outcroppings of schist distinguish sections of the Rand Mountains. For the most part, however, Quaternary-age alluvium characterizes much of the Mojave portion of the Study Area, with extensive Pleistocene- and Holocene-age alluvial fans coalescing along mountain fronts and fringing deep, sediment-filled valleys.

Local springs supply the only regular surface water to the Mojave Desert. The Owens River once flowed into Indian Wells, Searles, and Panamint valleys, but those waters stopped flowing by the early Holocene. Storms occasionally result in discharge from the many washes exiting the eastern Sierra Nevada, but these are typically rare, as most precipitation simply evaporates or sinks into coarse-grained alluvial soils.

CONTEMPORARY CLIMATE
The typical climate of south-central California is zonally sub-tropical (33-42 degrees north latitude) or Mediterranean, with hot dry summers and cool humid winters (Major 1977). The interaction between topography and atmospheric circulation provides the primary control for the region’s climate. A dominant influence is the cyclical shift in latitude and intensity of the semi-permanent Pacific High pressure cell (Anderson 1990; Hornbeck 1983; Major 1977). In the winter, as the Aleutian Low moves from its North Pacific position towards the equator, the Pacific High is pushed southward, and places California in line with low-pressure systems brought by westerly winds. A reduced ocean-to-land temperature gradient allows storms originating in the Pacific Ocean to move onshore, bringing widespread precipitation to the state. In montane regions, most winter precipitation occurs as snow. Beginning in the late spring, rapid heating of the continent creates a greater temperature gradient between the ocean and land. The Pacific high-pressure cell intensifies and moves northward, obstructing Pacific air masses from moving onshore, which in turn creates dryer conditions in the summer. During these months, precipitation is mainly limited to convective thunderstorms and sporadic rainfall from fronts originating to the south in the Gulf of California, or to the southwest in the Pacific Ocean (Anderson 1990).

Topographic relief also has a strong effect on patterns of temperature and precipitation in south-central California. The Sierra Nevada serves as a barrier to extremely cold winter air from the Great Basin. Cold winds that do make it over the Sierra are compressionally heated and dried, becoming the Santa Anas of southern California and the “northers” of the Central Valley (Hornbeck 1983). The Coast Ranges also serve as a buffer to the thick marine layer that mediates temperatures along the Pacific coast (Major 1977). More significantly however, the coastal and interior mountains have an important effect on precipitation. Due to the north-south orientation of the Coast Ranges and Sierra Nevada, the prevailing westerly winds are cooled as they rise to 470
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overcome the mountain crests, causing them to release heavy moisture. This results in high amounts of rain and snow on the windward, west-facing slopes of the mountains, but creates a rain shadow on the east sides.

Consequently, semi-arid to arid conditions prevail on the eastern side of the Coast Ranges, in the western San Joaquin Valley, and in the Great Basin and Mojave Desert east of the Sierra Nevada (Figure 3).

Coast Ranges
The eastern slope of the Diablo and Temblor ranges is hot and dry in the summer. The constraining mountains block cool marine air from the west, causing temperatures in the summer to be considerably warmer on the east side of the Coast Range than those of the interior valleys and ridges just to the west (Lindsey 1974); in the winter the opposite is true. Average annual precipitation in the uplands of the eastern Diablo Range can reach as much as 20 to 30 inches, while valley regions in the rainshadow to the east average between 2.5 and 6.5 inches annually (Figure 4).

San Joaquin Valley
Summer days in the southern San Joaquin Valley often exceed 38 °C (100 °F), with maximum average temperatures in June and July ranging between about 33-37 °C (92-98 °F) at Bakersfield and 36-37 °C (97-99 °F) at Coalinga. In winter (December to January), maximum average temperatures in these same localities range between 13 to 14.5 °C (57 and 58°F). Approximately 90% of annual rainfall occurs during the winter half of the year, between November and April; more than 50% occurs in January, February, and March. The summer months of June, July, and August are the driest of the year, with only about one percent of average annual rainfall originating from periodic thunderstorms during this season.

The orographic effect of the Coast Ranges, combined with latitude, produce clear geographic variation in annual precipitation across the valley, with less than 6.6 inches of rainfall annually on the western and southern sides of the basin, and between 6.6 and 15 inches annually on the eastern and northern sides (Figure 4). As a result of these differences, climate in dryer portions of the southern and western San Joaquin Valley is characterized as mid-latitude desert, while the remainder of the valley is semi-arid steppe (Figure 3; Hornbeck 1983; Major 1977).

Sierra Nevada
The Sierra Nevada Mountains form a boundary between the cool, moist Pacific air masses from the west and the warm, dry continental conditions of the Great Basin to the east. Climate is typical Mediterranean on the western slope, with warm, dry summers followed by wet, cool winters. Extreme annual variation in temperature and precipitation is characteristic of this region. A combination of eastward-moving storm systems and strong west-to-east elevational gradients result in a general pattern of increasing precipitation and decreasing temperature with rising elevation (Figure 4). Moisture-laden winter storms release large amounts of rain and snow as they ascend the western slope, leaving the eastern flanks of the Sierra with little precipitation (Major 1977).

Mean annual rainfall in the western foothills ranges from approximately 15 to 22 inches, while at midelevations average rainfall increases to between 22 and 32 inches (Figure 4). Above about 1,070 meters (3,500 feet), most precipitation occurs as winter snow, with annual depths averaging as much as 400 inches (ca. 50 inches of rain equivalent). Above about 2,440 meters (8,000 feet), precipitation decreases to the crest and continues to decline eastward (Major 1977). Snow blankets the highest peaks and alpine zone from November through May, with periodic snowfall recorded annually to elevations as low as 700 meters (2,300 feet). Although most of the yearly precipitation occurs between November and April, convective thunderstorms originating from the south are not uncommon at mid- to high-elevations in the Sierra during summer months, and contribute a measurable amount to yearly rainfall totals.

In the eastern foothills, the warmest months of the year are July and August with average maximum daily temperatures ranging from about 35 to 36 °C (96 to 98 °F; e.g., at Porterville). At higher elevations, temperatures are somewhat cooler, with maximum daily temperatures in the summer averaging about 32 °C (90 °F). Coolest conditions prevail at the highest elevations, where summer high temperatures average in the low 20s °C 471
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Figure 3. Koppen Climate Zones within District 6/9.

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Figure 4. Distribution of Annual Precipitation in District 6/9.

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(mid-70s °F; e.g., at Lodgepole). Between December and February, maximum daily temperatures at upper elevations are quite low, averaging just 3 to 4.5 °C (37 to 40 °F). The foothills are mild by comparison, with maximum daily temperatures in December and January averaging between 14 and 18 °C (57 and 64 °F). Most mid-elevation localities have average maximum daily winter temperatures just above 4.5 °C (40 °F).

Great Basin
The Great Basin is a mid-latitude desert, distinguished from the low-latitude Mojave Desert to the south by cooler temperatures in both summer and winter (Grayson 1993:22). In this regard, it is also different from the physiographic Basin and Range province, since cold desert portions of the Study Area are confined mainly to the region between the eastern escarpment of the Sierra Nevada and the White and Inyo mountains; those sections of the Basin and Range geomorphic province to the south and east fall within the bio-geographic Mojave Desert (Grayson 1993).

The rain shadow of the Sierra Nevada assures that little rainfall reaches the western Great Basin, with annual precipitation on the Owens Valley floor averaging less than six inches, about one-third of that obtained at similar elevations on the western slope. Above the Owens Valley in the White Mountains, most precipitation occurs as snow, with as much as 158 inches accumulating annually, about 19 inches of total precipitation. In contrast to the valley floor below, where only a minor amount of rainfall occurs during warm months (April through August), one-third of the annual precipitation in the White and Inyo mountains is derived from summer rain showers.

Maximum winter (December-January) temperatures at Independence on the Owens Valley floor average between 11 and 12 °C (53 and 54 °F), whereas further north at Bridgeport, they range between 5 and 6 °C (42 and 44 °F). Maximum summer (July-August) temperatures in these localities average between about 30 to 36 °C (87 to 97 °F). As would be expected given its higher elevation, both winter and summer temperatures are cooler in the mountains east of Owens Valley, where average daily winter temperatures range between about 0 and 1 °C (32 and 34 °F), while summer temperatures average between about 15 and 18 °C (60 and 65 °F).

Mojave Desert
As the name implies, the Mojave Desert is a very arid region due to its southern latitude and position east of the Sierra Nevada and Peninsular Range. In contrast to the Great Basin further north, this is considered a hot desert, with maximum winter temperatures averaging about 15 °C (60 °F) and summer temperatures averaging between about 35 and 39 °C (96 and 102 °F). Death Valley is considerably warmer, with temperatures in December and January averaging in the mid-60s and summer temperatures averaging between about 45 and 46 °C (113 and 115 °F).

The basins of this region receive less than five inches of rainfall annually, with as little as 2.25 inches on average at Death Valley. Like the rest of the Study Area, the Mojave Desert obtains its yearly rainfall primarily in winter, between December and March. This is unlike the Colorado Desert to the south which receives as much as half of its annual precipitation from summer monsoons. Furthermore, rainfall in the Mojave is sporadic, as particular localities can go many years without measurable precipitation (Major 1977). 474
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CHAPTER 3. EXISTING MODELS AND NOTIONS OF LANDSCAPE CHANGE Civilization exists by geological consent,
subject to change without notice.
~ Will Durant (Philosopher)
Our current understanding of the mechanisms and timing of late Pleistocene and Holocene landscape evolution in south-central California has been heavily influenced by geological studies of the alluvial fan and floodplain deposits in the San Joaquin Valley (Arkley 1954; 1962; Atwater 1980, 1982; Atwater and Belknap 1980; Harden and Marchand 1980; Marchand 1977a, 1977b; Marchand and Allwardt 1981; Olmstead and Davis 1961), as well as glacial outwash and lacustrine deposits east of the Sierra crest (Bach et al. 1992, 1996; Benson et al. 1998; Blackwelder 1931; Birkeland et al. 1976; Bursik and Gillespie 1993; Clark and Gillespie 1997; Curry 1969, 1971; Davis 1999a; Dorn 1996; Konrad and Clark 1998; Phillips et al. 1996; Smith 1979; Wahrhaftig and Birman 1965). The great majority of these studies assumed that glacial erosion and weathering were the primary mechanisms responsible for generating large amounts of sediment, ultimately transported by melt-water or periodic flood events to adjacent valleys via local rivers and streams. Because similar alluvial fan sequences were recognized along many of the formerly glaciated rivers exiting the Sierra Nevada, it was also assumed that the timing of fan deposition was in phase with glacial cycles and, therefore, development of the alluvial piedmont along the western Sierra and related alluvial deposits in the San Joaquin Valley was mainly a Pleistocene phenomenon. While, it has rarely been specified whether the primary period of sediment deposition occurred during glacial advance or retreat, both Shelmon (1972) and Weismann (Weismann et al. 2002; Weismann et al. 2005) suggest that glacial recession was the primary mechanism of sediment transport, indicating that deposition should have been greatest following the glacial maximum.

In contrast to expansive research focused on the Central Valley of California and adjacent slopes of the western Sierra Nevada, the steep eastern escarpment has been subject to a variety of relatively idiosyncratic studies.

This region lacks a synthetic overview correlating regional landforms, especially outside the Owens River system and, as a result, no reliance on an overarching model of landscape change has yet emerged. Nevertheless, if glacial cycles were the primary impetus for alluvial fan development on the western slope, this mechanism too should have had a strong influence on the nature and timing of fan aggradation in the Owens Valley and other basins fronting glaciated mountains east of the Sierra Nevada.

Although the glacial model has served as an organizing framework for numerous geological studies throughout central California, few attempts have been made to actually demonstrate that glacial periods in the Sierra Nevada correlate with the age of alluvial deposits presumed to derive from these cycles. To date, temporal linkages between particular glacial periods and outwash deposits have been based largely on relative dating techniques, such as geomorphic position, cross-cutting relations, and soil development (Bach and Elliot-Fisk 1996; Birkeland et al. 1976; Birkeland et al. 1980; Birkeland and Burke 1988; Swanson et al. 1993, among others). In many cases, one-to-one correlations between glacial intervals and outwash deposits could not be established because the resulting sediments were missing from central parts of glacial drainages, particularly west of the Sierra crest (Janda and Croft 1967; Matthes 1960). While some glacial moraines and outwash deposits have been radiocarbon dated, especially on the eastern slopes of the Sierra (Bach et al. 1996; Bursik and Gillespie 1993; Curry 1971; Clark and Gillespie 1997; Dorn 1996; Konrad and Clark 1998; Phillips et al. 1996), the absolute age of most glacial deposits remains poorly constrained and assumed ages remain highly questionable.

Recent work in the Coast Ranges on the western side of the San Joaquin Valley (e.g., Lettis 1985) and in unglaciated watersheds of the Sierra Nevada (Meyer and Dalldorf 2004; Meyer and Rosenthal 2008) has shown that a similar sequence of alluvial fan and floodplain deposits is present in these regions too, and that extensive deposits of post-glacial, Holocene-age alluvium occurs throughout the valleys of western California (e.g., Lettis 1982, 1985; Meyer 1996; Meyer and Rosenthal 2008; Rosenthal and Meyer 2004a, 2004b). Likewise, geological studies in the western Great Basin and northern Mojave Desert have shown that extensive post-glacial deposition also occurred in regions east of the Sierra Nevada (Harvey and Wells 2003; Mahan et al. 2007; McDonald et al. 475
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2003; Miller and Amoroso 2007; Wells et al. 1987; Young 2007), calling into question glacial cycles as a primary mechanism for sediment transport and deposition in central California.

These studies point to the need for a more inclusive model of landscape evolution which decouples erosion, sediment transport, and deposition from glacial cycles, and provides a mechanism that can accommodate landscape transformations that occurred in glaciated and unglaciated watersheds alike, as well as during more recent times when glacial processes were inconsequential. Before developing such a model, the following chapter provides an overview of prevailing notions of landscape evolution, focusing on inherent inconsistencies and contradictory evidence of landform age that has emerged over the last 30 years. We begin by briefly summarizing glacial cycles in the Sierra Nevada, incorporating new evidence for the timing of glacial advance and retreat, and the relationship between those cycles and high and low lake stands recorded in pluvial basins east and west of the Sierra Nevada. The next section examines prevailing models of landscape evolution in central California in relation to glacial cycles, emphasizing research conducted in the San Joaquin Valley and adjacent uplands where many of the formative geological studies occurred. In that section we introduce stratigraphic nomenclature, and point out how the vagaries of relative-age assignments have resulted in ongoing problems of correlation. Lastly we present recent radiocarbon and stratigraphic evidence which effectively demonstrates inaccuracies in the prevailing glacial model of landscape change.

SIERRA NEVADA GLACIAL SEQUENCE
It is evident that relative-age dating methods
do not have sufficient precision and resolution
to permit definitive distinction of deposits
of the Tahoe, Tenaya and Tioga age classes.
~ David Fullerton - Geologist (1986:165)
More than twenty thousand years ago, the crest of the Sierra Nevada was covered by a massive sheet of glacial ice that extended from the Feather River to the headwaters of the Kaweah River (north to south). Fed by an upper ice cap roughly 50 kilometers (32 miles) wide, continuous lobes of ice moved down the main valleys on both sides of the Sierra, carving out the bedrock and leaving behind a series of terminal moraines that record multiple advances and retreats.

While glaciation of the Sierra Nevada has long been a subject of intense study (Wahrhaftig and Birman 1965), the exact number and age of particular glacial events are still open to debate (Dupre et al. 1991; Kaufman et al. 2004; Fullerton 1986). Six episodes of Pleistocene glaciation are widely recognized, known from oldest to youngest as the McGee, Sherwin, Tahoe, Tenaya, Tioga, and Recess Peaks (Fullerton 1986; Guyton 1998; Hill 2006). Though the ages of the earliest advances are not well defined, the McGee is estimated to be at least 1.5- million years old, the Sherwin approximately 820,000 years old, and the Tahoe bracketed somewhere between about 150,000 and 40,000 years old (Gillespie and Zehfuss 2004:54; Hill 2006:311).

Of primary importance for the current study, two late Pleistocene glacial cycles include the Tenaya and the last major advance known as the Tioga glaciation (Blackwelder 1931; Curry 1969; Fullerton 1986). A radiocarbon date of about 30,000 cal BP from glacial out-washes in the Kings River fan may provide a beginning date for the Tioga advance (Atwater et al. 1986). The end of the Tioga advance is better constrained by several radiocarbon dates from glaciated basins in the Sierra dating less than 16,000 years cal BP (Table 1), consistent with worldwide evidence that glaciers began to recede about 17,400 cal BP (Schaefer et al. 2006). Terminal moraines of the Tioga advance descend to elevations as low as 2,280 meters (7,480 feet) in the Tuolumne River drainage (Huber 2004), but were higher to the south where they did not extend below about an average of 2,500 meters (8,200 feet; Kaufman et al. 2004). However, apart from concurring that the Tioga advance represents the last glacial maximum, there is little agreement among researchers as to the correlation of Tioga-age alluvial and morainal deposits between different drainages and even within single valleys (Fullerton 1986:165). 476
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Table 1. Radiocarbon Dates from Late Pleistocene Glacial Moraines in the Sierra Nevada.

LOCALITY

STRATIGRAPHIC

POSITION

MATERIAL
DATED
14CBP CAL BP REFERENCE

PINE CREEK
Outermost Tioga moraines Surface Rock varnish 19,050 ± 420 22,602 Dorn et al. (1987) Innermost Tioga moraines Surface Rock varnish 13,170 ± 200 15,780 -

OSGOOD SWAMP
In terminal Tioga moraine of
Echo Lakes Glacier
Above glacial flour Bulk sediment 9,900 ± 800 11,448 Adam (1967)

SWAMP LAKE
Near upper limit of Tioga ice,
North Fork
In glacial flour Bulk sediment 15,565 ± 820 18,597 Batchelder (1980) Stanislaus Valley Above glacial flour Bulk sediment 14,035 ± 510 - -

LAKE MORAN
In highest Tioga moraines,
North Fork
Above glacial flour Bulk sediment 12,180 ± 260 16,821 Byrne (1988) Stanislaus Valley In glacial flour Mono Craters Ash 14,700-14,800 - - SWAMP LAKE – YOSEMITE
Covered by Tioga glaciation,
Tuolumne Valley
Above glacier flour Bulk sediment 13,690 ±340 16,419 Smith and Anderson (1992)

SIESTA LAKE
In Tioga moraine n/a Bulk sediment 11,280 ±60 13,274 Brunelle and Anderson (2003)

TIOGA PASS POND
Covered by Tioga glaciation,
Sierra crest
Above Mono Craters ash Bulk sediment 8760 ± 240 9,838 Anderson (1990)

STARKWEATHER POND
In Tioga moraines In sand and silts Bulk sediment 10,879 ± 150 12,929 Anderson (1990)

LAUREL CREEK CANYON
In Tioga/Recess Peak moraine n/a Carbonized leaves 13,600 ± 120 16,329 Pohl et al. (1996); Clark et al. (1995)

BARRETT LAKE
Area of Hilgard deposits Above glacial flour Bulk sediment 11,730 ± 430 13,817 Anderson (1987)

UPPER BABOON LAKES
In Recess Peak moraines Above glacial flour Bulk sediment 11,190 ± 70 13,161 Clark and Gillespie (1997)

CENTRAL BABOON LAKES
In Recess Peak moraines Above glacial flour Gyttja 10,880 ± 60 12,940 Clark and Gillespie (1997)

GABBOTT MEADOW LAKE
Covered by Tioga glaciation In sandy gravel Bulk sediment 10,500 ± 140 12,461 Mackey and Sullivan (1991)

BUNKER LAKE
Covered by Tioga glaciation Above glacial flour Charcoal? 11,180 ± 180 13,090 Edlund (1994a)

GRASSY LAKE
Covered by Tioga glaciation Above glacial flour Bulk sediment 12.360 ± 100 13,380 Edlund (1994b) Notes: Table modified and expanded from Edlund 1991.

A separate glaciation, the Hilgard, identified by a number of researchers as a late Pleistocene or early Holocene event, has recently been refuted (Clark and Gillespie 1997). Type-moraines for the Hilgard advance are now thought to be recessional features associated with the Tioga glaciation (Birkeland et al. 1976; Clark and Gillespie 1997). Likewise, a re-evaluation of the smaller Recess Peak glaciation, once thought to be a late Holocene phenomenon (Scuderi 1987), places this advance and retreat between 14,200 and 13,100 cal BP, or latest Pleistocene in age (Clark and Gillespie 1997; Gillespie and Zehfuss 2004). Glacial ice generated by the 477
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Recess Peak advance was substantially smaller than the Tioga ice mass, with the average vertical extent being about 3,375 meters (11,070 feet), or 335 meters (1,100 feet) higher than the maximum Tioga advance (Figure 5).

The Little Ice Age or Matthes glaciation, which began between 650 and 620 years ago, is the only truly Holocene-age glacial advance now recognized in the Sierra, lasting about 500 years (c.f., Curry 1969, 1971; Scuderi 1987; Wahrhaftig and Birman 1965; Wood 1975). In comparison, Little Ice Age glaciers only reached to about 3,520 meters (11,550 feet) at their lowest extent, or about 145 meters (475 feet) higher than during the Recess Peak advance (Figure 5). The Matthes and Recess Peak advances were the only glaciations to occur during the span of human occupation. The Sierra Nevada was essentially unglaciated for the intervening 12,000 years or more, including a cooling interval identified as the Younger Dryas. The overall timing of the glacial sequence is summarized below in Table 2.

Table 2. Generalized Sierra Nevada Glacial Sequence.

GLACIAL OR

NON-GLACIAL PERIOD
DESCRIPTION AGE CAL BP a POSSIBLE

DURATION (YEARS)
Little Ice Age/Matthes Glacial cycle (retreat) 650-150
(400-150)
500
(250)
Holocene Non-glacial warming 11,500-650 10,850
Younger Dryas Non-glacial cooling 12,800-11,600 1,200
Recess Peak Glacial cycle (retreat) 14,200-13,100
(13,600-13,100)
1,100
(500)
Tioga III or IV Glacial cycle (retreat) 25,000-15,000
(19,000-15,000)
10,000
(4000)
Tenaya or Tioga I Glacial cycle (retreat) ~42,000-28,000 (~36,000-28,000)
14,000
(8000)
Tahoe II Glacial cycle ~50,000-42,000 8,000
Mono Basin or Tahoe I Glacial cycle ~80,000-60,000 20,000 Notes: Adapted from Gillespie and Zehfuss (2004:Table 1), Kaufman et al. (2004:Table 2), and Phillips et al. (1996:Table 1); a Age estimates of 40,000 years or more based on radiometric data other than radiocarbon are not necessarily calibrated; Parentheses ( ) denote timing and duration of glacial retreats.

GREAT BASIN LAKE AND RIVER SEQUENCE
As some writers ñ especially those who are given to
solving the mysteries of nature from their closets ñ have thought that lakes filling true rock basins are a rarity, and have even doubted whether they exist at all, we shall be interested in examining the result of glacial actionÖ
~ Israel Russell ñ Geologist (1889:281).

At the height of the most recent glacial maximum, about 22,000 years ago, seasonal melt-water and wellcharged groundwater systems maintained stream flow in drainages emanating from the glacier-capped mountains.

Tributary streams led to large rivers ending in closed basins where a combination of high stream flow and reduced evaporation formed expansive lakes. This is an “ice-age” snapshot of the eastern Sierra Nevada and western Great Basin traditionally understood to be the landscape of the earliest human inhabitants of the region. Since the time of Russell’s nineteenth-century expedition to Mono Lake, geologists, geomorphologists, and archaeologists working on the eastern side of the Sierra have exposed and documented a much more complicated interplay of global climate and local environments, resulting in a diverse record of local landform response. The regional mosaic of uplifted mountains, glacier-cut valleys, alluvial bajadas, and broad, once-lacustrine, valley bottoms is a testament to this landscape dynamic.
478
Nevada
California
Fresno Inyo
Tulare
Mono
Madera
Kings
Tuolumne
Equilibrium Line Altitude (ELA) - Long-Term Average Position Along Glacier (meters above mean sea level) 3,040 - 3,375 m Tioga
3,376 - 3,520 m Recess Peak
3,521 - 4,399 m Little Ice Age/Mathes
Miles
Kilometers
0 0
10 20
20 40
Figure 5. Average Extent of Latest Pleistocene and Holocene Glacial Advances.

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Notions of Glaciers and Lakes
The notion of a late Pleistocene, direct “ice age” link between Sierra glaciation and pluvial lake highstands within Mono, Owens, and China Lake (Indian Wells) basins has been decoupled through a greater understanding of post-glacial climate patterns as well as clear documentation of structural relationships between well-dated lake features and generalized glacial landforms (Grayson 1993:111). The steeply uplifted mountainfront of the eastern Sierra preserves a detailed record of the recessional phases of the most recent glacial (Tioga) cycle. Tectonic uplift forces drainages to cut through older mountain-front landforms so that glacial features are preserved; unfortunately, deposition has shifted basinward where recent fans bury lacustrine features on the margins of Owens Valley.

Although numerous creative dating methods have shown promise (Phillips 2008; Phillips et al. 1996), Sierra glacial features tend to be difficult to date with any accuracy beyond some limiting minimum based on exposure of surfaces once beneath the ice mass (for example., see Table 1). Older Tahoe-age features may have been subdued by erosion and soil development and may extend beyond the mountain-front, whereas more recent Tioga-age features are sharp and clearly up-valley from the more expansive Tahoe landforms. Lacustrine records containing stratigraphic isotopic, sedimentologic, or paleontologic (e.g., ostracods) evidence provide robust proxy data for reconstructing glacial and lacustrine sequences (Benson et al. 1996; Benson et al. 1997; Benson et al. 1998; Bradbury and Forester 2002; Phillips 2008; Phillips et al. 1996). While a linkage between glacial and lacustrine processes is assumed by these proxies, the popular notion of a strict synchronicity between glacial or “ice-age” maximum (~22,000 years ago) and pluvial lake highstands (~17,000 years ago) is misguided.

The increased resolution of lacustrine records, along with field observations of multiple recessional landforms, has led researchers to posit multiple Tioga pulses within the broader glacial cycle. The glacial maximum (lowest equilibrium altitude), between about 25,000 and 22,000 years ago, is marked by Tioga II deposits and lake proxies indicating relatively low lake stands, if not complete desiccation (Benson et al. 1997). Glacial systems remained near their maximum extent for several thousand years with only slight recession and expansion fluctuations. Landforms believed to be associated with these post-maximum fluctuations are occasionally labeled as Tioga III features; however, these features are neither geographically extensive nor commonly recognized. Glacial features preserved above the Mono Lake Basin, noted by Russell (1889), reveal that late Tioga glaciers began retreating prior to 16,000 years ago (Bursik and Gillespie 1993:33-34). A significant pause and possible final expansion within the general glacial retreat is marked by well-documented Tioga IV deposits dating to about 16,000 years ago. A general regression in the depth and extent of regional lake systems corresponds to Tioga IV.

The final Tioga recession, after the Tioga IV pause, was followed by a rise of Lake Russell (pluvial Mono Lake) to its late Pleistocene highstand (Benson et al. 1998; Bursik and Gillespie 1993). A similar pattern is documented in glacial landforms and lacustrine records elsewhere along the eastern Sierra Nevada.

Tioga fluctuations in the Sierra show equivalents in the White Mountains, the most southerly late Pleistocene glaciated range in the Great Basin (Grayson 1993:108). The early and late Middle Creek glaciations in the eastern cirques of the White Mountains are Tioga-age equivalents; the late Middle Creek ended about 16,000 years ago. Pluvial highstands throughout the Owens River system, from Owens Lake through Lake Searles, clearly post-date Tioga glacial recession.

Notions of the Owens River System
Reality is the squiggly stuff.
~ Ron King - Archaeologist
During the Pleistocene, the Owens River system drained almost the entire eastern Sierra Front, from Mono Lake to China Lake, and extended to Panamint Valley and Death Valley of the Mojave Desert (Figure 6).

A drainage system of this extent was rare, however. By the late Pleistocene, the paleo-Owens River only connected the intermediate basins of Owens, China, Searles, and Panamint lakes (Smith and Street-Perrott 1983). Today the river terminates at the nearly dry lakebed of Owens Lake. 480
1000
1500
2000
2500
3000
3500
4000
4500
500
Sea level 0
Owens
River Owens
Lake
1145 m
1081 m
China Lake
665 m
(Spillway) Searles Lake
690 m Panamint Lake
355 m Death Valley Lake
("Lake Manly")
87 m
655 m 493 m
317 m
-86 m
Sierra
Nevada
Elevation in Meters
Figure 6. Paleoconnections along the Owens River Drainage System.

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Smith and Street-Perrott (1983) and Benson et al. (1990) provide discussions of pluvial lake chronologies along the Owens River system by focusing on the stratigraphy of pluvial Lake Searles. When Owens Lake reached its outlet it overflowed to Rose Valley which, in turn, overflowed to Indian Wells Valley and China Lake. The modern elevation of the Owens Lake sill, beneath the Haiwee reservoirs, is 1,145 meters (3,756 feet). When China Lake reached a depth of approximately ten meters (33 feet), at an elevation of 665 meters (2,182 feet), it overflowed to the deep basin of Searles Valley. Searles Lake filled considerably, to a depth of 172 meters (564 feet), before coalescing with the waters of China Lake to form pluvial Lake Searles. The lake continued to rise until reaching its sill with Panamint Valley where it would have been almost 200 meters deep (656 feet), maintaining a surface elevation of 690 meters (2,264 feet).

This expansive network of rivers and lakes are a key for understanding the structure of late Pleistocene and early Holocene landscape change in the western Great Basin; however, the chronological resolution of postglacial lake expansions and river connection remains elusive. Early studies focused on Searles Basin as pivotal for understanding the system’s history (Smith 1987; Smith and Street-Perrott 1983). The Searles Basin remains important because it retains a deep stratigraphic record and, because it lies in the rain shadow of the Sierra Nevada, local surface runoff and internal input had only a minor influence on lake fluctuations. Thus, the Searles record provides an excellent proxy of the hydrological history of the preceding (up-drainage) basins. Moreover, rising lake levels in Lake Searles provides direct information on the depth of China Lake. In turn, China Lake must have received input from the Owens River to overflow into Searles Basin.

Lake Searles experienced dramatic fluctuations during the late Pleistocene between about 35,000 and 17,500 cal BP (Benson et al. 1990; Smith and Street-Perrott 1983). The pluvial lake, like other regional lakes, experienced a dramatic recession between 17,500 and 15,500 years ago. The lake then fluctuated at moderate levels until about 12,850 years ago, with a distinct increase between 12,850 and 12,200 cal BP. After this final transgression, the lake receded and remained very low or dry with minor oscillation throughout the Holocene (Benson et al. 1990). A radiocarbon date of 15,500 cal BP on rock varnish from an outflow terrace between China and Searles basins indicates the terrace has been exposed and the lakes did not coalesce since at least that time (Benson et al. 1990). Smith reported Holocene lakes in both China (Smith and Davis 1978) and Searles (Smith and Street-Perrott 1983) basins, but these have not been well-documented. While Holocene lake stands, derived from intra-basin drainage, likely occurred in these separate basins, geomorphic features associated with low-level, brief transgressions have not been discovered.

Warren (2008; see also Rosenthal et al. 2001) has shown that Clovis projectile points—the earliest accepted evidence for human occupation in the region—are clustered at elevations below the outflow sill of China Lake Basin. He has interpreted this spatial patterning as indicative of the “Clovis drought” (after Haynes 1991) which immediately predates the brief return to pluvial conditions marking the late Younger-Dryas. During the dry interval of the Clovis drought, the Owens River was confined to Owens Valley. Just prior to 12,200 years ago, fluctuations of the global climatic Younger-Dryas event (12,800-11,500 cal BP) seemingly produced a series of brief increases in Sierra runoff (Benson et al. 1997), probably accompanied by reduced evaporation (Grayson 1993), and forced a return of Lake Owens and extension of the Owens River system through Rose Valley, China Lake, and into Searles Lake. Numerous Clovis points from the Coso Junction site, situated along the former course of the Owens River in Rose Valley (Borden 1971), also support the idea that river flow resumed during Clovis times.

Owens Lake Basin, the “gatekeeper” of the hydrological system, has received copious study via a series of lake cores (Benson 2004; Benson et al. 1996; Benson et al. 1997; Phillips 2008; Phillips et al. 1996) and descriptive and chronological analysis of littoral environments and neotectonics (Bacon et al. 2006; Orme and Orme 2008). Retreating from an extended period of highstands, it is clear that Owens Lake experienced significant desiccation during a pause in Tioga glaciation that formed the Tioga IV terminal moraines. This drying event is evident as prominent desiccation features and frosted quartz grains in the record of core OL84 between 18,300 and 15,800 years ago. Following this early desiccation, isotope data (delta-18O) show four wet intervals (W1-4) when basin outflow via the lower Owens River (to Rose Valley and China Lake) reduced the level of isotope saturation, indicated by lower delta-18O measures. The W2 interval of Benson et al. (1997) shows two sub-peaks and may have lasted almost 1,500 years. Although Benson et al. (1997) do not specifically state that the late wet events (W3 or W4) forced Owens Lake to its sill, the significant reduction in isotope saturation 482
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along with the 500-year duration of each event suggests that outflow was likely (cf. Bacon et al. 2006). The wet periods are bracketed by very dry intervals with relatively high isotope saturation. The first two dry intervals (D1 and D2) resulted in relatively brief lake regressions. The third (D3), at the beginning of the Younger-Dryas, was significant enough to allow formation of a sub-aerial weathering profile on the Owens lakebed. The final dry period (D4) marks a significant transition to generally dry conditions, although the record shows fluctuating delta-18O levels, with a significant decrease at about 10,000 years ago, lasting into the Holocene.

Bacon et al. (2006) present a very different picture of Owens Lake Basin. Their review of dated subaerial, littoral, and sub-aqueous features and fauna, either collected by the authors or obtained from previous studies, including the lake core studies, limits the potential for basin outflow. Their interpretation of the Pleistocene-Holocene transition retains significant hydrological fluctuation, but the authors posit that Owens Lake did not have outflow (i.e., it remained a closed basin) after a final highstand between 16,000 and 15,000 years ago. Their record also indicates that the amplitude and duration of early Holocene lakestands was much greater than indicated by the upper sections of well-studied cores.

Figure 7 presents an updated lake level curve focusing on the interval between circa 21,500 and 10,000 years ago. The simplified curve is derived from lake level and isotope information from Owens Lake (Bacon et al. 2006; Benson and Bischoff 1993; Benson et al. 1997; Orme and Orme 2008), China Lake (Warren 2000; Young et al. 2001), Searles Lake (Benson et al. 1990), and on-going field studies in Rose Valley. Although significant progress has been made (Bacon et al. 2006; Benson 2004; Orme and Orme 2008; Phillips 2008), the figure illustrates that our understanding of lake levels in Searles Basin, and throughout the system, is incomplete.

As a proxy for the Sierra front landscape conditions, the record provides important information about the Pleistocene/Holocene transition. Water levels in the Searles Basin are dependent on input from China Lake and the Owens River system. Because the overflow sill between China and Searles basin is so low (less than 10 meters [33 feet] above the floor of Indian Wells Valley), and the Searles Basin occupies a much lower-elevation valley, changes in hydrologic inflow and outflow have a greater effect in the basin of China Lake than at Searles. If there is flow in the lower Owens River, via Rose Valley, due to Lake Owens overflow and Sierra input, China Lake fills relatively quickly before overflowing to Searles. Therefore, increasing lake level in the Searles Basin requires outflow from the upstream basin, which in turn produces a relatively stable level in China Lake. If the lake in Searles Basin is receding, we can assume that input from the Owens River system has ceased and China Lake has dropped below its sill. Once the river is cut off, due to the shallowness of China Lake Basin, it is likely that lake desiccation would significantly out-pace that at Searles.

The interpretations of Bacon et al. (2006) do not align with downstream datasets from the Searles Basin (Phillips 2008; Orme and Orme 2008), though they do not necessarily contradict information from Owens Lake cores (Benson et al. 1997). Young (n.d.) has documented early Holocene wet intervals in Rose Valley, where organic black mats on lacustrine deposits near sill levels suggest external water sources. Orme and Orme (2008) have indicated that the elevation of Owens sill has changed since formation of highstand shorelines and find evidence of tectonic uplift along the active margin of the Coso Range. Although something of a “ghost in the machine,” this might be a useful explanation for discrepancies in the lacustrine records (Phillips 2008) of the tectonically active trough that forms the course of the Owens River. The structure of the Owens River is not only significant for understanding prehistoric resource distribution along the Sierra front and into the California Great Basin; it is also a useful proxy for reconstructing the character of depositional and erosional regimes within and adjacent to the drainage system.

San Joaquin Valley Lake Records
Tulare Lake and Buena Vista Lake were historically the largest bodies of surface water in the San Joaquin Valley. Before the lakes were drained and reclaimed for agriculture in the early nineteenth-century, the Buena Vista basin captured runoff supplied by the Kern River and all other streams that drain the southern end of the valley. Both lakes were subject to relatively rapid fluctuations in their overall water levels as they regularly responded to annual runoff and periodic floods or droughts (Grunsky 1898a, 1898b; Mendenhall et al. 1916), and both were partially or completely enclosed (“dammed”) by large alluvial fans originating near the base of the 483
Clovis Drought
Rose Valley Black Mats
W1
W3 W2
W4
D1
D2
D3
D4
?
10,000 12,000 15,000 20,000 Younger - Dryas Tioga IV Pause Waning Tioga Glaciation (Max ~22 000)
Outflow to Panamint
China/Searles Sill
China Lake Stands
?
?
Erosion
Soil Development
7000
650
675
700
cal Years BP
Elevation in Meters (China/Searles Basin)
Owens
Desiccation
Lava End Indian Wells Coso II
from Benson et al. (1997) with Wet (W)/Dry (D) cycles based on isotopic signatures. from Bacon et al. (2003) based on synthesis of regional radiocarbon database.

Owens to Searles Lake Proxies: Upward trends (right-to-left) show Owens sill overflow and river contribution to Lake China, downward trends show Lake Owens regression and desiccation of lower Owens River; provides general transgression/regression lake level direction for pluvial Lake Searles.

Regional Geomorphic Response:

Generalized Lake Searles Level Trend
Rising LakeFalling Lake
Figure 7. Owens to China to Searles Proxy Lake Indicators.

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- - -- _ ______ _ ._. _ -
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l1TTTTTl l l l l l l l l l l l l l l l l - I -ll lll lli rn rn rn l ill 484
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Sierra foothills to the east. At times of major flooding, water flowed northward from Buena Vista Lake through a convoluted network of shallow channels, known as Buttonwillow Slough, on its way to Tulare Lake. Tulare Lake was the primary hydrologic basin for all runoff from the southern San Joaquin Valley, including all drainages from the Kings River to the Kern River that carried glacial water from the upper Sierra Nevada (see Figure 2). As such, Tulare Lake has been a settling basin for alluvium transported by these drainages, both east and west of the valley’s southern axis.

Buena Vista Basin
A basic sketch of Buena Vista Basin’s depositional history can be pieced together based on the age and context of several radiocarbon dates obtained by various geologic and archaeological studies from sediments underlying the lakebed (Croft 1968, 1972; Fredrickson and Grossman 1977; Lofgren 1975; Manning 1968; Marchand and Allwardt 1981). These dates indicate that at least 18 meters (59 feet) of sediment were deposited in the basin since the Tenaya glacial advance about 36,370 cal BP (W-2336), and that sand deposits appear to record Tioga-related outwash over the interval from about 20,290 cal BP (W-1504) to 15,820 cal BP (W-1652).

Extensive deposition during this time is consistent with a date of 16,845 cal BP (W-1650) obtained on wood buried more than 12 meters (39 feet) below the surface of the Kern River fan near Bakersfield (Marchand and Allwardt 1981).

In parts of Buena Vista Basin, Croft (1968, 1972) identified a thick layer of fine-grained lacustrine or marsh deposits (i.e., “A clay”) that appears to mark the Pleistocene to Holocene boundary. Wood from the upper part of the “A clay” yielded a date of 10,175 cal BP (W-1505), indicating that it and the overlying 11.6 meters (38.1 feet) of sediment are Holocene in age. An early Holocene date of 9516 cal BP (Beta-169380) was obtained on a buried soil located along Broad Creek to the west of the basin (Young 2003), and freshwater shells associated with a buried cultural deposit at KER-116 between 2.6 and 4.5 meters (8.5-14.8 feet) below surface on the southwestern edge of Buena Vista Lake produced dates of 8380 and 7740 cal BP (LJ-1356-57, and I-1928, respectively; Fredrickson and Grossman 1977). Charcoal from a buried colluvial deposit along the southern side of the lake generated a middle Holocene date of 4810 cal BP (LJ-314). This suggests that debris flows occasionally made their way to the valley floor from the San Emigdio Mountains and may be inter-fingered with fluvial deposits (Fredrickson and Grossman 1977; Hubbs et al. 1962). Dates of 1300 to 1100 cal BP on archeological materials from surface sites KER-39 and KER-116 located on the western margin of the basin suggest a lake was also present during the latest Holocene (Hartzell 1992). As such, the Buena Vista Basin contains a reasonably complete depositional record from the latest Pleistocene through much of the Holocene. The history of lake fluctuations in Buena Vista Basin, however, has yet to be evaluated.

Tulare Lake
To the north of Buena Vista Basin, lacustrine deposits of Tioga-age (Chatom silt) were identified in the Tulare Lake Basin, but evidence for the two proceeding glacial cycles (Tahoe and Tenaya) has not yet been found (Atwater et al. 1986; Davis 1999a). Atwater et al. (1986) contend that glaciation produced large outwash deposits on the Kings River fan, which created a dam that blocked the usual outlet of the lake to the north. This model suggests the “fan dam” was deposited beginning about 28,000 cal BP during the Tioga glacial advance (i.e., coeval with Chatom silt), and that this lead to an increase in the overall size and depth of the lake basin. Once the fan dam was in place, it would have presumably increased the basin’s overall ability to capture and store sediments for long periods. If these changes grant Tulare Lake the unusual potential to record “the timing, magnitude, and climatic context of Sierra Nevada glaciation” as claimed by Atwater et al. (1986:109), then its depositional record should be even more complete than that of Buena Vista Lake. Yet oddly, deposits that might correlate with the Buena Vista “A clay” of Croft (1968, 1972) are not recognized in Tulare Lake.

A subsequent study by Davis (1999a) indicates that the lake’s depositional center records a “gap in sedimentation” for the interval from about 21,800 to 11,800 cal BP, a period which fully encompasses the Tioga glacial maximum and retreat, and the entire Recess Peak glacial cycle. Davis interpreted the gap as an erosional contact (not a lake low stand) created when “the alluvial dam impounding the lake was breached by a throughflowing Kern River” (Davis 1999a:255). Though no further explanation is given, this scenario implies a breach 485
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may have occurred even before the fan dam was completely built, and is thus at odds with the Atwater et al. (1986) depositional sequence which suggests continued dam building until about 18,000 cal BP.

Because it is highly unlikely that erosion could have ever been efficient or pervasive enough to remove all depositional evidence of a particular glacial or interglacial period within such a broad and shallow basin, it is puzzling to imagine how Tulare Lake could contain a record of some glaciations and not others, especially when the Kings River, Buena Vista Basin, and all other glaciated and unglaciated western Sierra Nevada drainages contain deposits coeval with the last three or four major glacial cycles (see Table 2). Furthermore, the Tulare Lake record indicates deposition resumed around 11,800 cal BP within the basin, and was relatively continuous through the rest of the Holocene (Atwater et al. 1986; Davis 1999a; Negrini et al. 2006). Thus, not only were these lacustrine deposits laid down during the decidedly non-glacial conditions that typified the Holocene, but they are twice as thick as the Tioga-age Chatom silt (about 6 versus 3 meters [19 versus 10 feet] respectively).

Latest Pleistocene and Holocene lake level histories for Tulare Basin have previously been inferred by both Davis (1999a) and Negrini et al. (2006). Based on the nature of sediment deposition and changing abundances and types of pelagic algae and littoral pollen, Davis (1999a) described periods of high and low lake levels spanning the last 30,000 years. This work was based on core samples retrieved from the lowest portion of Tulare Basin (i.e., the basin’s depocenter), and provides information on whether relatively deep or shallow water conditions occurred at the coring site, interpreted as either high or low lake stands (Davis 1999a).

To better understand changes in the size of Tulare Lake during the late Pleistocene and Holocene, Negrini and Wigand (2003 and Negrini et al. 2006) studied sedimentary records from below a prominent wavecut terrace along the southwestern edge of the basin, which they termed the Rambla shoreline. Negrini’s and Weigand’s study added important detail on the sedimentary record of the basin margin and areal extent of Tulare Lake at different times in the past. However, they relied heavily on Davis’ (1999a) findings to infer the elevation of high lake stands, but provided no constraining dates which demonstrate the actual extent of these transgressions. For example, Negrini’s inferred lake level curve provides no direct evidence for high stands above the 64 meter elevation (210 feet), which represents the modern sill level. Nevertheless, he infers high stands well above that level during the early Holocene (i.e., ca. 9000 and 8500 to 7500 cal BP), middle Holocene (ca. 5800 to 5500 cal BP) and during the latest Holocene (after 500 cal BP).

To provide a more complete picture of the latest Pleistocene and Holocene history of Tulare Lake, we plotted the distribution of all radiocarbon dates thus far retrieved from the basin, distinguishing between those that were deposited sub-aqueously, at or near lake level, or in terrestrial contexts above lake level (Figure 8; Figure 9). The latter dates are the most significant as they provide constraints on the maximum elevation of the lake at various times in the past. The terrestrial dates derive from various contexts (Appendix A), the majority of which are buried soils and archaeological deposits. Dates inferred to be at or near the maximum elevation of the lake derive mainly from marsh or beach deposits, whereas those from below lake level originate from lake clays and silts (e.g., the Blakely Canal Silt).

The current data set suggests that Tulare Lake reached its highest elevations only recently, apparently within the last 1,000 years. Early Holocene shorelines appear to have remained around the 63-meter (207-foot) elevation, about one meter (three feet) below the modern sill elevation, while those associated with the middle Holocene and beginning of the late Holocene appear to have been even lower, between about 58 and 56 meters (190 and 184 feet) in elevation about 2000 cal BP, well below the lowest levels recorded historically (Grunsky 1898b). After 2,000 years ago, the lake rose significantly, attaining its highest levels perhaps as recently as the historic period, although the highest transgressions were probably short lived (Grunsky 1898b).

That the lake stood well below the 63-meter (207 feet) level during most of the Holocene is clearly evident from radiocarbon dates obtained from the Los Gatos Creek fan. Along with the Kings River fan, alluvial deposits originating from Los Gatos Creek create the primary impoundment for Tulare Lake basin. Four radiocarbon dates from buried soils at two separate localities on the distal Los Gatos Creek fan range between 13,835 and 13,495 cal BP (OS-72701, OS-72702, Beta-137204, and Beta-255484) and range in elevation between 61.9 and 63.0 meters (203.1 and 206.6 feet). In the Omaha Canal, these late Pleistocene buried soils are immediately capped by lake deposits containing Anadonta shell in growth position. A sample of one of these shells 486
Kern
Contour (meters) above mean sea level
62 64
66 0 5 10
Miles
0 10 20
Kilometers
Historic Lake
Sand Ridge
Kimberlina
Shoreline
Dudley Ridge
Rambla
Shoreline
Fresno
Tulare
Kings
Figure 8. Tulare Lake Highstands and Inferred Shorelines.

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California Department of Transportation, District 6/9
Geoarchaeological Study
29 Far Western
487
0 2000 4000 6000 8000 10,000 12,000 14,000 16,000 18,000 20,000 22,000 48 cal Years BP
Elevation in Meters (amsl)
50 52
54 56
58 60
62 64
66 68
70 Historic Sill Level
Unconformity
Chatom Silt
Blakely Canal Silt
+
+
+
+
+
+
+
+
++
+
_ _
_
_
_ _
_
_
_
_
_
__
_
_
_
_
_
_
_
_
_ _
+
+
++
+
High Stand (Davis 1999a)High Stand (Davis 1999a)
?
? ?
?
? ? ?
_
+
Radiocarbon Dates
Above Lake Level
Near Lake Level
Below Lake Level
Highest Recorded Lake Level (1861)
Lowest Recorded Lake Level (1883)
Figure 9. Lake Level History of Tulare Basin.

Transportation Enhancement Activities Program
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Geoarchaeological Study
Far Western 30
0 ,-i-c>---
I '
I
I
I
--. -
1 I
t
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Transportation Enhancement Activities Program 31 Far Western California Department of Transportation, District 6/9
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returned a radiocarbon date of 175 cal BP (OS-73445), indicating lake deposits in this locality are very recent in age. The absence of intervening depositional strata demonstrates that the lake did not attain a significant high stand above 63-meters (207 feet) during the latest Pleistocene and throughout most of the Holocene.

Based on our recent mapping (see Chapter 4), it appears that late Holocene deposition on the Kings River fan likely raised the sill-level of the basin about one meter (three feet) beginning about 2000 cal BP, causing the elevation of the shoreline to rise during recent times. This implies that lake level histories in the basin were controlled as much by changes in the sill level as water in-put related to climatic fluctuations (cf, Davis 1999a). In fact, the absence of a depositional record in the basin from about 21,000 to 11,500 cal BP (Davis 1999a) might suggest that the Kings River was flowing northward at that time, rather than spilling southward into Tulare Basin.

A northward-flowing buried channel of the Kings River may be evidence of this hydrological shift (Weissmann et al. 2002; Weissmann et al. 2005).

To better understand the spatial extent of Tulare Lake at different times in the past, we plotted the elevation of the modern sill (64.3 meters [211 feet]) as well as two hypothesized shorelines using maximum (67.05 meters [219.98 feet]) and minimum (58.5 meters [191.9 feet]) elevations of the lake reported historically by Grunsky (1898b). What becomes evident from this exercise is that there are at least two previous shorelines that have geomorphic expressions within the basin. The wave-cut Rambla shoreline, defined by Negrini (Negrini and Wigand 2003; Negrini et al. 2006), was almost certainly the location of the lake margin throughout the latest Pleistocene and Holocene due to the steepness of the alluvial piedmont along the western edge of the basin. The 62-meter (203 feet) shoreline at that location would have also extended along Dudley Ridge, and linked up with the same elevations along Sand Ridge, another prominent shoreline feature which wraps the southern end of the basin (see Figure 8).

Because the maximum elevations of both Dudley Ridge and Sand Ridge lie above the height of the modern sill at 64 meters (210 feet), and late Pleistocene fossils dated more than 17,000 years old (Fenenga 1991; Garber 1989; West et al. 1991) have been found at Dudley Ridge, it seems that these are not recent landscape features and could not have been deposited sub-aqueously during the late Pleistocene or Holocene (c.f., Negrini et al. 2006). Rather these linear features either represent beach berms formed by wave action, or were originally deposited sub-aqueously earlier in the Pleistocene (Chatom silt times?) when depositional records are absent in the central part of the basin. In addition to the shoreline represented by Dudley and Sand ridges, a second probable shoreline is evident further south in the basin, representing an even higher lake stand. This shoreline runs parallel to Sand Ridge, about eight miles to the southeast, at the 64- and 66-meter (210- and 217 feet) contours and is associated with a linear sand deposit mapped in the Kimberlina Series. This landscape feature lies precisely at the level of the highest lake recorded historically (Grunsky 1898b) and further indicates that there is a much greater separation in shoreline features along the low-gradient southeastern edge of the basin than is present along the Rambla shoreline to the west.

Future research on lake-level histories in the basin should focus on those regions beyond Sand Ridge, where the spatial separation of shorelines is the greatest. If our analysis is correct, lake deposits in that part of the basin should date well before 13,000 cal BP or after 2,000 cal BP. Furthermore, unlike pluvial lakes in the Great Basin, the history of Tulare Lake appears to have been strongly controlled by changes in the basins sill elevation, rather than merely recording changes in precipitation and run-off.

Conclusions
Pluvial Lake histories east and west of the Sierra Nevada provide an important record of water run-off and sediment transport from the adjacent slopes of the Sierra Nevada. Contrary to long-held notions, recent studies of basins east of the Sierra Nevada demonstrate that lake levels were generally lowest during the last glacial maximum, now thought to have occurred around 22,000 years ago, reaching their highest stands between about 18,000 and 17,000 years ago. Pluvial lake systems appear to have remained linked up to about 16,000 years ago, after which lake levels fluctuated regularly, but outflow sills appear to have rarely been reached, if at all, during the latest Pleistocene and early Holocene. Differences of opinion remain, however, and estimates of the size and duration of latest Pleistocene lake stands east of the Sierra continue to be elusive. To the extent that the glacial model of landscape evolution is correct, it is likely that sediment transport and deposition was highest when water 489
Far Western 32 Transportation Enhancement Activities Program California Department of Transportation, District 6/9
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run-off was greatest—not at the glacial maximum, but during the recessional phase of the Tioga glaciation.

Pluvial lakes west of the Sierra Nevada, have not been studied to the same extent as those to the east, but current information suggests Buena Vista Basin retains a depositional record of end-Pleistocene run-off, while the much larger Tulare Basin is missing a depositional record for this interval. In the latter case, this may be a function of local geomorphology, representing a time when the Kings River flowed northward away from Tulare Basin. If this is true, Tulare Lake was not receiving significant water input at a time when pluvial lakes east of the Sierra were reaching their post-glacial high stands. It is also clear from modern research that no significant glacial cycles occurred after the Recess Peak advance in the terminal Pleistocene (except for the relatively minor Little Ice-Age advance), precluding these processes as a mechanism of landscape evolution during the Holocene.

THE GLACIAL MODEL AND SAN JOAQUIN VALLEY DEPOSITIONAL SEQUENCE The essential fact as to the present valley surface is that it is a direct result of stream action. It has everywhere been built up by deposition from the streams or from the fluctuating lakes that are themselves dependent upon the streams;
and it is formed of materials brought by the streams
from the mountainous portions of their drainage basins
where they are eroding instead of depositing.
~ Mendenhall et al. (1916:21)
Arkley (1954, 1962) was among the first to study late Quaternary alluvial sequences in the eastern San Joaquin Valley and to relate these to cycles of glaciation. Based on work in Merced and Stanislaus counties, Davis and Hall (1959) identified two main Pleistocene-age geological units, known as the Riverbank (middle Pleistocene) and Modesto (late Pleistocene) formations. While younger Holocene-age deposits were recognized in the valley, these were often grouped and identified simply as “recent alluvium” or “basin deposits” without any further age divisions. In the 1970s, the term “post-Modesto formation” was introduced and applied to Holoceneage deposits by Marchand (1977a) who, along with Allwardt, identified, described, and mapped four subHolocene units in the northeastern part of the San Joaquin Valley, including parts of the current Study Area (Marchand and Allwardt 1981). This stratigraphic terminology was quickly adopted by other researchers and applied to similar alluvial sequences elsewhere in Central California (Table 3), including most alluvial landforms in the San Joaquin Valley, Sacramento-San Joaquin Delta region, lower Sacramento Valley, and even parts of the northern Transverse Ranges and western Mojave Desert.

Riverbank Formation
Where exposed at the surface, Riverbank deposits represent alluvial fans and floodplains that have been heavily dissected and truncated by erosion. These landforms have reddish-colored soils with well-developed argillic (Bt) horizons. Fossil mammal remains and radiometric dating of the Rockland Ash, which lies below the Riverbank Formation in the Sacramento Valley, place the age of this formation between about 450,000 and 100,000 years old (Hansen and Begg 1970). Upper and lower sub-units (referred to as “members”) of the Riverbank Formation in the San Joaquin Valley (Marchand and Allwardt 1981) are correlated with upper and middle Riverbank units (respectively) in the Sacramento Valley (Blake et al. 1992; Busacca et al. 1989; Helley and Harwood 1985). Deposits of the upper Riverbank Formation are inset and topographically below those of the lower Riverbank formation. The older sub-unit is also distinguished by surfaces that are more rolling and dissected than the younger. In the foothills of the Sierra Nevada, Harden and Marchand (1980) correlate the middle Riverbank with Bowie Flat deposits, and the upper Riverbank with Oroville deposits based on geomorphic position and similar weathering profiles; Bowie Flat deposits are found at only a few locations in the foothills, while the younger Oroville deposits are more extensive (Biggar et al. 1978:87). 490
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Table 3. Previous Correlations of Glacial and Stratigraphic Sequences in Central California and Adjacent Areas.

SACRAMENTO

VALLEY-AMERICAN

RIVER (GLACIATED)
a

NORTHEAST SAN

JOAQUIN VALLEY
(GLACIATED)

WEST-CENTRAL

SIERRA FOOTHILLS
(UNGLACIATED)

CHOWCHILLA RIVER

FAN (UNGLACIATED)

SAN JOAQUIN RIVER

FAN (GLACIATED)

SAN JOAQUIN AND

KINGS RIVER FANS
(GLACIATED)

KINGS RIVER FAN
(GLACIATED)

TULARE LAKE AND

KINGS RIVER FAN

WEST-CENTRAL SAN

JOAQUIN VALLEY
(UNGLACIATED)

NORTH TRANSVERSE

RANGES AND SOUTH

SAN JOAQUIN VALLEY

ANTELOPE VALLEY IN

WESTERN MOJAVE

DESERT (UNGLACIATED)

TIME PERIOD
(YEARS CAL BP)

GLACIAL STAGE
(AGE CAL BP)
SHLEMON (1967,
1972)

MARCHAND AND
ALLWARDT (1981)

HARDEN AND
MARCHAND (1979)
HELLEY (1966) JANDA (1965) JANDA
AND CROFT (1967)

HUNTINGTON
(1980)
WEISSMANN ET AL.
(2002)
ATWATER ET AL. (1986);
DAVIS (1999)
LETTIS (1982, 1985,
1988)
HALL (1984) PONTI (1985); PONTI ET
AL. (1981)
Modern
(<0 or 1950 AD)
na Not recognized Post-Modesto IV Keystone deposits Recent channel and sidestream alluvium
Recent alluvium
(undivided)
Holocene 4? and
Basin Deposits
Not recognized Not recognized Not recognized Q8 Q8 - Post-Palmdale II (<70 cal BP)
Historic-Era
(150-0)
na Not recognized Post-Modesto III Keystone deposits Recent channel and sidestream alluvium
Recent alluvium
(undivided)
Holocene 4? and
Basin Deposits
Not recognized Not recognized Not recognized Q7 Q8 - Post-Palmdale II (<70 cal BP)
Latest Holocene
(2000-150)
Little Ice Age (650-
150)
Holocene
(undivided)
Post-Modesto II Keystone deposits Recent channel and
sidestream alluvium
Recent alluvium
(undivided)
Holocene 3? and
Basin Deposits
Holocene
(undivided)
Blakely Canal silt
(undivided and
uncorrelated)
Patterson and Dos
Palos Alluvium
(unvided and
uncorrelated)
Q6 Q7 - Palmdale I
Late Holocene
(4000-2000)
Minor neoglaciation? Holocene
(undivided)
Post-Modesto II Keystone deposits Recent channel and
sidestream alluvium
Recent alluvium
(undivided)
Holocene 3? and
Basin Deposits
Holocene
(undivided)
Blakely Canal silt
(undivided)
Patterson and Dos
Palos Alluvium
(undivided)
Q6 (<2500 cal BP) Q7 - Palmdale I
Middle Holocene
(7000-4000)
na Holocene
(undivided)
No deposit or
correlate
No deposit or
correlate
N/A or Upper
Modesto?
Recent alluvium
(undivided)
Holocene 2? and
Basin Deposits
Holocene
(undivided)
Blakely Canal silt
(undivided)
Patterson and Dos
Palos Alluvium
(undivided)
No deposit or
correlate
No deposit or correlate
Early Holocene
(11,500-7000)
na Holocene
(undivided)
Post-Modesto I;
Upper Modesto
Sonora deposits N/A or Upper
Modesto?
Upper Modesto?
(undivided)
Holocene 1 and
Modesto 5w?
(aeolian sands)
Holocene
(undivided)
Blakely Canal silt
(<11,800)
Upper San Luis
Ranch Alluvium
(>10,000 cal BP)
Q4 and Q5 (>7000
cal BP)
Q6 - Upper Palmdale
(>10,000 cal BP)
Latest Pleistocene
(15,000-11,500)
Recess Peak
(14,200-13,100)
Upper Modesto
(uncorrelated)
Upper Modesto
(uncorrelated)
Sonora deposits Upper Modesto
(undivided and
uncorrelated)
Upper Modesto
(uncorrelated)
Modesto 5 and 5w Modesto
(undivided and
uncorrelated)
No deposit or correlate Upper San Luis
Ranch Alluvium
(uncorrelated)
Q4 and Q5
(undivided and
uncorrelated)
Q6 - Upper Palmdale
(uncorrelated)
Late Pleistocene
(25,000-15,000)
Tioga I-IV (25,000-
15,000)
Upper Modesto Upper Modesto Sonora deposits Upper Modesto Upper Modesto Modesto 3 and 4 Modesto (undivided)
Upper Modesto -
Chatom silt (28-21.8 ka)
Upper San Luis
Ranch Alluvium
Q4 and Q5
(undivided and
uncorrelated)
Q6 - Upper Palmdale
(uncorrelated)
Late Pleistocene
(~42,000-28,000)
Tenaya or Tahoe II
(~42,000-28,000)
Lower Modesto?
(uncorrelated)
Upper Modesto Wyandotte deposits Dune Sand (preTioga?) Upper Modesto Modesto 3 (Kings River only)
Modesto
(undivided)
No deposit or correlate Lower San Luis
Ranch Alluvium
Q3? (uncorrelated) Q6 - Lower Palmdale
(undivided and
uncorrelated)
Late Pleistocene
(~50,000-42,000)
Tahoe I and/or II
(~50,000-42,000)
Lower Modesto Lower Modesto Wyandotte deposits? Lower Modesto Lower Modesto Modesto 1 and 2 Modesto (undivided)
No deposit or correlate Lower San Luis
Ranch Alluvium
Q3 Q4 and Q5 -Lower
Palmdale (undivided
and uncorrelated)
Late Middle Pleistocene
(~80,000-60,000)
Mono Basin or
Tahoe I
Riverbank Riverbank Oroville (lower) and
Bowie Flat (upper)
Riverbank Riverbank Riverbank 1, 2, 3 Riverbank West Lake silt Los Banos Alluvium No deposit or correlate
Q1, Q2, and Q3 -
Upper, Middle, Lower
TylerHorse)
Notes: a
Not located within Study Area.
491
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Modesto Formation
As defined by previous researchers, the Modesto Formation consists of alluvial fans and floodplains with flat to gently sloping surfaces that are commonly incised by modern stream and river channels near the foothills, but otherwise show little evidence of erosional dissection. These deposits are inset and topographically lie below the Riverbank Formation in positions near the foothills, and are often covered by younger alluvial sediments near the valley floor. The Modesto Formation is generally mapped near existing stream and river channels across much of the Central Valley floor (Busacca 1982; Helley and Harwood 1985), but “Modesto-age” channels are likely buried in some alluvial fans along the valley’s eastern side (Atwater 1980; Busacca et al. 1989; Shlemon 1971; Weismann et al. 2002; Weismann et al. 2005). Isolated deposits of wind-blown (aeolian) dune sand, that may be Modesto-age, occur in the Delta (see “Piper sand” of Cosby 1941) and along the eastern edge of the San Joaquin Valley (Atwater 1980, 1982).

Upper Modesto deposits form a sequence of as many as four or more fans (Modesto 1-5) and terraces along each of the major (glaciated) Sierra rivers, which “represent four erosional or depositional phases” (Marchand and Allwardt 1981:59). Within the smaller, unglaciated watersheds of the Sierra foothills, however, upper Modesto deposits create a single terrace (Marchand and Allwardt 1981:59) and were often buried by Holocene-age colluvial fans (Harden and Marchand 1980). The ages of the upper and lower sub-units of the Modesto Formation are only partly constrained by stratigraphic and radiocarbon evidence. The age of the lower sub-unit was initially estimated to be approximately 40,000 to 30,000 years old (late Pleistocene), and the age of the upper sub-unit about 30,000 to 9,000 years old (Harden 1987; Helley and Harwood 1985; Marchand and Allwardt 1981). The age of lower Modesto deposits was later revised to about 33,000 to 26,000 years old, and upper Modesto deposits to about 26,000 to 11,500 years old based on evidence from the Kings River fan (Atwater et al. 1986).

It has been widely assumed that the Modesto formation correlates with late Pleistocene or Wisconsin glaciation (Tahoe, Tenaya, and Tioga stages), and Riverbank deposits with an earlier glacial interval, usually the Mono Basin stage. Because the number, extent, and age of glacial cycles in the Sierra Nevada remain in dispute and age estimates have changed substantially over the last 30 years, previous correlations between glacial intervals and episodes of alluvial deposition are inconsistent and often contradictory (Table 4). While pre-Tioga glaciations are admittedly inconsequential for archaeology, each of these earlier glacial cycles would presumably have produced a corresponding outwash deposit if the link between glaciation and deposition is as strong as often suggested.

In the unglaciated drainages of the western San Joaquin Valley, Lettis (1982) identified a sequence of alluvial deposits that he termed the Los Banos alluvium (middle Pleistocene), San Luis Ranch alluvium (late Pleistocene and early Holocene), Patterson alluvium (middle and late Holocene), and Dos Palos alluvium (latest Holocene), from oldest to youngest respectively (Lettis 1982). The typical geomorphic and stratigraphic relationship between these west-side units is shown in Figure 10, and the overall relationship between the east-side and west-side units within the San Joaquin Valley is shown in Figure 11. Because the western San Joaquin Valley drainages were not glaciated, Lettis (1982) suggests that large-scale climatic changes were responsible for the formation of these landforms. Thus, stratigraphic sequences of the eastern and western San Joaquin Valley are generally presumed to reflect differences between glacially driven (east) and climatically driven (west) landscape evolution.

Furthermore, a distinct middle Holocene-age deposit has not been identified or formally defined as part of previous geological studies of the San Joaquin Valley and Sierra Nevada foothills (see Table 3; e.g., Hall 1984; Harden and Marchand 1980; Marchand and Allwardt 1981); neither buried nor at the surface. The absence of deposits dating to the middle Holocene is both curious and conspicuous given that sedimentation is thought to have been almost continuous in and near the axis of the San Joaquin Valley (Atwater et al. 1986; Busacca et al. 1989; Huntington 1980; Lettis 1982; Olmstead and Davis 1961). The potential lack of a middle Holocene-age unit is problematic because it may indicate a missing time interval (“gap”) in the stratigraphic record, and possibly the cultural record as well.
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Geoarchaeological Study
Table 4. Relationship of Glacial Stages with Deposits in the San Joaquin Valley and Adjoining Foothills.

GLACIAL STAGE AND TIME PERIOD

MONO BASIN

OR TAHOE I

TAHOE I

AND/OR II

TENAYA OR

TAHOE II
TIOGA
I-IV
RECESS
PEAK
LITTLE

ICE AGE
REGION

OR AREA
(SOURCE NO.) LATE MIDDLE

PLEISTOCENE
(~80,000-60,000)
LATE

PLEISTOCENE
(~50,000-42,000)
LATE

PLEISTOCENE
(~42,000-28,000)
LATE

PLEISTOCENE
(25,000-15,000)
LATEST

PLEISTOCENE
(14,200-13,100)
LATEST

HOLOCENE
(650-150)
Madera County
and Eastern San
Joaquin 1
Riverbank Lower Modesto Upper Modesto Upper Modesto Upper Modesto (uncorrelated)
No correlated
deposit
Chowchilla River
Fan 2 (unglaciated)
Riverbank Lower Modesto Dune Sand (preTioga?) Upper Modesto Upper Modesto (uncorrelated)
No correlated
deposit
San Joaquin River
Fan 3
Riverbank Lower Modesto Upper Modesto Upper Modesto Upper Modesto (uncorrelated)
No correlated
deposit
San Joaquin and
Kings River Fans 4
Riverbank 1, 2, 3 Modesto 1, 2 Modesto 3 Modesto 3, 4 Modesto 5, 5w (uncorrelated)
No correlated
deposit
Kings River Fan 5 Riverbank Modesto
(undivided)
Modesto
(undivided)
Modesto
(undivided)
Modesto
(uncorrelated)
No correlated
deposit
Tulare Lake and
Kings River Fan 6
West Lake silt no deposition
or correlate
no deposition
or correlate
Upper Modesto -
Chatom silt
no deposition
or correlate
No correlated
deposit
Western San
Joaquin Valley
(unglaciated)
Los Banos Alluvium
(uncorrelated)
Lower San Luis
Ranch Alluvium
(uncorrelated)
Lower San Luis
Ranch Alluvium
(uncorrelated)
Upper San Luis
Ranch Alluvium
(uncorrelated)
Upper San Luis
Ranch Alluvium
(uncorrelated)
Patterson and Dos
Palos Alluvium
(uncorrelated)
Sources: 1 – Marchand (1977a, b); Marchand and Allwardt (1981); 2 – Helley (1966); 3 – Janda and Croft (1967); 4 – Huntington (1980); 5 – Weismann et al. (2002); 6 – Atwater et al. (1986) and Davis (1999); 7 – Lettis (1982, 1985, 1988).

Notes: Numbers assigned to Riverbank and Modesto formations by Huntington (1980).

CONSTRAINING THE AGES OF MODESTO AND POST-MODESTO DEPOSITS With their four-dimensional minds, and in their
interdisciplinary ultra verbal way,
geologists can wiggle out of almost anything.
~ John McPhee (author)
The chronologic and stratigraphic relationships between Modesto and post-Modesto formations are widely viewed as a temporal and physical boundary that allows latest Pleistocene-age deposits to be distinguished from those that are Holocene in age. While the stratigraphic break between Modesto and Post-Modesto has been widely recognized (i.e., unconformity), the age of the two formations has not been well constrained by previous studies. As shown in Table 5, researchers variously place the age of the upper Modesto formation anywhere between about 28,000 and 7800 cal BP, with a minimum age extending some 3,700 years into the Holocene.

Table 5. Summary of Proposed Age Ranges for Upper Modesto and Post-Modesto Deposits.

AREA (REFERENCE) UPPER MODESTO POST-MODESTO
Sierra Foothills (Harden and Marchand 1980) 11.5-7.8 ka 7.8-0 ka Sacramento Valley (Busacca et al. 1989) 16.7-9.2 ka 9.2-0 ka San Joaquin Valley (Harden 1987) ~28-9.2 ka 9.2-0 ka
San Joaquin Valley (Marchand and Allwardt 1981) 16.7-10.2 ka 10.2-0 ka San Joaquin Valley (Atwater et al. 1986) ~28-11.5 ka 11.5-0 ka Maximum Combined Age Range ~28-7.8 ka 7.8-0 ka
Notes: ka – Kiloannum (1,000 years) in calibrated years (cal BP); radiocarbon dates greater than ~22 ka were calibrated according to Fairbanks et al. (2005).
494
Alluvium of
Patterson
Alluvium of
San Luis Ranch
Alluvium of
Los Banos
Late to Latest
Holocene
Middle to Late
Holocene
Late Pleistocene to Early Holocene
Middle to Late
Pleistocene
Middle Pleistocene
Patterson Alluvium Middle
to Late Holocene
Patterson Alluvium
San Luis Ranch Alluvium Late to Latest Holocene
Late Pleistocene to Early Holocene
Bedrock
Bedrock
Tulare FormationTulare Formation
Los Banos Alluvium
Middle Pleistocene
Upper Unit Lower Unit Upper Unit Lower and Middle Units Early to Middle
Pleistocene
Buried Soil
(Adapted from Lettis 1985: Figure 5)
(Adapted from Lettis 1985: Figure 7)
a: Sequence of Inset Stream Terraces and Nested Alluvial Fans in West-central San Joaquin Valley. b: Cross-section of Terrace Sequence and Stratigraphic Units on the East Side of the Diablo Range.

Figure 10. Major Geomorphic and Stratigraphic Units in Western San Joaquin Valley.

Transportation Enhancement Activities Program
California Department of Transportation, District 6/9
Geoarchaeological Study
37 Far Western
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Late Pleistocene to
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Mid-Pleistocene to Early Holocene
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Middle to Late Pleistocene
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Turlock Lake Formation
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Dos Palos Alluvium
Late to Latest Holocene
San Joaquin River
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Early to Middle Pleistocene
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(Simplified from Lettis 1982: Plate 25 and Adapted from Bartow 1991: Figure 3) Figure 11. Schematic Cross Section of Major Stratigraphic Units in the San Joaquin Valley.

Transportation Enhancement Activities Program
California Department of Transportation, District 6/9
Geoarchaeological Study
Far Western 38
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Transportation Enhancement Activities Program 39 Far Western California Department of Transportation, District 6/9
Geoarchaeological Study
If the general range is correct, the upper Modesto formation may have been deposited thousands of years after the Tioga glaciers had receded, and even after the Recess Peak glacial retreat (<13,500 cal BP). If some portion of the upper Modesto formation is early Holocene in age, then it is technically part of the post-Modesto formation as originally conceived. While uncertainty about the upper Modesto’s minimum age is small on a geologic time-scale, it is unacceptably large for archaeological purposes, since the purported age range spans initial human colonization of North America.

Previous Soil-Age Relationships
Quaternary geologists have regularly used soil development to determine the relative ages of alluvial deposits and geomorphic surfaces in central California. Generally speaking, soils with very weakly developed A/C or argillic (Bw or cambic) horizons are often associated with upper Modesto deposits, while soils having strongly developed argillic (Bt) horizons are correlated with lower Modesto or Riverbank deposits (Marchand and Allwardt 1981:59). Temporally significant soil types previously associated with the Modesto and post-Modesto formations are summarized in Table 6. The geomorphic and stratigraphic relationship between these strata and soil types is illustrated in Figure 12.

From the time that Arkley (1954, 1962) first recognized and documented the stratigraphic significance of particular soil types, soil development has been the main criteria for distinguishing and mapping alluvial deposits of different ages throughout the San Joaquin Valley (see Table 3; Atwater 1982, Atwater et al. 1986; Blake et al. 1992; Birkeland 1974; Busacca et al. 1989; Harden 1987; Helley 1966; Helley and Harwood 1985; Huntington 1980; Janda and Croft 1967; Lettis 1982, 1988; Ponti 1985; Shlemon 1967, 1972; Weismann et al. 2002, 2005).

The direct application of this relative dating approach has since been drawn into question because many soils with similar degrees of development have been mapped at the surfaces of different landforms identified as either latest Pleistocene or Holocene in age. This suggests that either the assumed age of these landforms is incorrect or soil development is a poor indicator of landform age (Meyer and Rosenthal 2008). As is evident in Table 6, the estimated age of the same surface soils varies widely among researchers, with several considered to be solely Pleistocene-age by some and solely Holocene-age by others.

One such example was found in the northwestern Sacramento Valley where it was recognized that the development of certain surface soils was inconsistent with a sequence of late Quaternary alluvial terraces identified there. In this case, moderately developed Arbuckle-series soils occur on both the lower Modesto and upper Modesto terraces, while weakly developed Cortina and Yolo soils are mapped on both upper Modesto and postModesto terraces (Steele 1979:34-35). It has since been shown, however, that both the Cortina and Yolo soils in this region are only latest Holocene in age (Meyer and Rosenthal 2008).

In the northeastern Sacramento Valley, an upper Modesto deposit dated between about 11,500 and 9200 cal BP bears a relatively undeveloped surface soil with a A/Bw/C profile (Conejo series) thought to be at the “young end of this range” (Busacca et al. 1989:19, 41). Subsequent geoarchaeological evidence from the Best Slough floodplain in Yuba County indicates that Conejo-series soils are actually late Holocene in age (<4000 cal BP), and can contain buried archaeological deposits less than 2,000 years old (Eidsness and Meyer 1999). Other recent geoarchaeological studies have identified Holocene-age deposits with weak (Bw) to moderate (Bt) argillic soil horizons throughout central California—many overlying archaeological sites—that include soils previously considered to be late Pleistocene in age (Meyer 2000; Meyer and Dalldorf 2004; Meyer and Rosenthal 1997, 2008; Rosenthal and Meyer 2004a, 2009).

Radiocarbon Assessment of “Modesto” Soil-Age Relationships Marchand and Allwardt (1981) have explicitly identified the Fresno soil series as being representative of the lower Modesto formation; however, several recent studies indicate that these soils are instead associated with upper Modesto-age landforms (Table 6). These soils were initially interpreted as being more than 40,000 years old because they exhibit a strongly developed argillic horizon and silica-cemented hardpan (Marchand and Allwardt 1981:56). At the same time, it was noted that the age of the Fresno soil may be overestimated because the fine-grained texture and high sodium content of these soils can increase the rate of development (Atwater 1982; Arkley 1962, 1964; Birkeland 1974:112; Huntington 1980; Jenny 1941:99). 497
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Honcut
Wyman
Ryer Snelling
Snelling Snelling
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Greenfield
Atwater
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Snelling,
San Joaquin
San Joaquin
Montpellier
Raynor,
Pentz,
Peters
Whitney, Rocklin
Rocklin, Montpellier
Hanford, Grangeville
Redding
Riverwash
Tujunga,
Grangeville
Merced River
Dry Creek
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Hopeton
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acid variants
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= Riverbank Formation= Modesto Formation= Post Modesto Formation= Turlock Lake Formation= Tertiary Deposits r
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= Riverbank Formation= Modesto Formation= Post Modesto Formation Delhi, Dello, Hilmar
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Grangeville
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Grangeville
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b. Section of Merced River West of Stevinson. (After Marchand and Allwardt 1981) a. Section of Merced River Near Snelling. (After Marchand and Allwardt 1981) r
m
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Figure 12. Schematic Cross Sections of Merced River Showing Relation of Soils to Geomorphic Surfaces and Stratigraphic Units.

Transportation Enhancement Activities Program
California Department of Transportation, District 6/9
Geoarchaeological Study
Far Western 40
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Transportation Enhancement Activities Program 41 Far Western California Department of Transportation, District 6/9
Geoarchaeological Study
Table 6. Summary of Soil Types Previously Associated with Modesto and Post-Modesto Deposits.

MODESTO FORMATION POST-MODESTO FORMATION

REGION OR AREA (REFERENCE) LATE PLEISTOCENE
(~50,000 TO 25,000)

UNDIFFERENTIATED
(~50,000 TO 11,500)

LATE OR LATEST PLEISTOCENE
(25,000 TO 11,500)

LATEST PLEISTOCENE
(15,000 TO 11,500)

EARLIEST HOLOCENE
(11,500 TO ~9200)

HOLOCENE - HISTORIC-ERA
(11,500 TO 0)
Sacramento Valley - Northeast
(Busacca 1982; Busacca et al. 1989)
N/A Gridley, Live Oak, Marcus, Ryer,
Wyman, Yuvas
N/A N/A Conejo Honcut
Sacramento Valley - American River
(Shlemon 1967)
N/A Greenfield Honcut Honcut Honcut Columbia, Hanford, (Freeport), Sacramento
Sacramento-San Joaquin Delta
(Atwater 1980, 1982; Atwater and
Marchand 1980)
Antioch, Riz, San Ysidro N/A Bear Creek, Brentwood, Delhi, Dinuba, Hanford, Honcut, Fresno,
Oakley, Piper, Rincon, Stockton,
Zamora
Bear Creek, Brentwood, Delhi,
Dinuba, Hanford, Honcut, Fresno,
Oakley, Piper, Rincon, Stockton,
Zamora
Bear Creek, Brentwood, Delhi,
Dinuba, Hanford, Honcut, Fresno,
Oakley, Piper, Rincon, Stockton,
Zamora
Burns, Correra, Capay, Clear Lake,
Columbia, Egbert, Sacramento,
Sorrento, Staten, Ryde, Venice
San Joaquin Valley - Northeast
(Marchand 1977a)
Borden, Dinuba, Fresno, Greenfield,
Lewis Pachappa, Pond, Rossi, Ryer,
Traver, Waukena, Wyman
N/A Chino, Hanford, Hesperia, Landlow,
Merced, Pachappa, Temple, Visalia,
Wunjey
Chino, Hanford, Hesperia, Landlow,
Merced, Pachappa, Temple, Visalia,
Wunjey
Chino, Hanford, Hesperia, Landlow,
Merced, Pachappa, Temple, Visalia,
Wunjey
Bear Creek, Columbia, Foster,
Grangeville, Hanford, Honcut,
Merced, Temple, Tujunga, Yolo
Sierra Foothills - West-Central
(Harden and Marchand 1980)
Chular, Greenfield N/A Hanford, Hildreath, Marguerite,
Visalia
Hanford, Hildreath, Marguerite,
Visalia
Hanford, Hildreath, Marguerite,
Visalia <7.8 ka
Grangeville
San Joaquin Valley - Northeast
(Marchand and Allwardt 1981)
Atwater, Borden, Fresno, Waukena Dinuba, El Peco, Greenfield, Pachappa, Pond, Rossi, Ryer, Traver,
Wyman
Chino, Hanford, Hesperia, Landlow,
Merced, Pachappa, Temple, Visalia,
Wunjey
Chino, Delhi, Dello, Hanford,
Hesperia, Hilmar, Landlow, Merced,
Pachappa, Temple, Visalia, Wunjey
Chino, Delhi, Dello, Hanford,
Hesperia, Hilmar, Landlow, Merced,
Pachappa, Temple, Visalia, Wunjey
Bear Creek, Columbia, Foster,
Grangeville, Hanford, Honcut,
Merced, Temple, Tujunga, Yolo
San Joaquin Valley - West-Central
(Lettis 1982)
N/A Fresno, Waukena Lethent (Volta), Lillis (Levis), Rincon (Pleasanton), Rossi
Lethent (Volta), Lillis (Levis), Rincon
(Pleasanton), Rossi
Lethent (Volta), Lillis (Levis), Rincon
(Pleasanton), Rossi
Columbia, Merced, Panoche,
Sacramento, Temple, Willows, Yolo
(Sorrento)
San Joaquin Valley - Northeast
(Harden 1987)
Greenfield N/A Hanford, Honcut Hanford, Honcut Hanford, Honcut Grangeville, Hanford Chowchilla River Fan
(Helley 1966)
Atwater, Borden, Greenfield, Pachappa N/A Hanford, Tujunga Hanford, Tujunga Hanford, Tujunga N/A San Joaquin River Fan
(Janda and Croft 1967)
Atwater, Border, Fresno, Greenfield,
Hanford (ripperdan), Hilmar, Ryer
N/A Delhi, Dello, Dinuba, El Peco, Fresno,
Grangeville, Greenfield, Hanford,
Honcut, Marguerite, Merced,
Pachappa, Tujunga, Wyman
Delhi, Dello, Dinuba, El Peco, Fresno,
Grangeville, Greenfield, Hanford,
Honcut, Marguerite, Merced,
Pachappa, Tujunga, Wyman
N/A Bear Creek, Columbia, Delhi, Foster,
Grangeville, Hanford, Honcut,
Merced, Tujunga, Yolo
San Joaquin and Kings River Fans
(Huntington 1980)
Atwater, Fresno, Greenfield, Pond,
Rossi variant
N/A Cajon variant, El Peco, Hanford,
Hesperia variant, Pollasky, Traver,
Tujunga
Calhi, Cajon variant, Chino, Delhi,
Dello, Hanford
Calhi, Cajon variant, Chino, Delhi,
Dello, Hanford
Chino, Foster, Grangeville, Hanford,
Honcut, Merced, Piper, Temple,
Tujunga (Soboda), Visalia?
Mojave Desert - Western Antelope Valley
(Ponti 1985)
Borden, Greenfield N/A Cajon, Hanford Cajon, Hanford Cajon, Hanford Arizo, Grangeville, Soboda, Tujunga 499
500
Transportation Enhancement Activities Program 43 Far Western California Department of Transportation, District 6/9
Geoarchaeological Study
To better constrain the age of the Fresno Series, a radiocarbon sample was obtained as part of the current study from beneath this soil in an exposure along the Chowchilla Canal in Madera County (Figure 13; Location Madera 1). The sample originated from a well-developed buried soil identified more than three meters (10 feet) below the surface (see photos in Chapter 4). The resulting date of 19,080 cal BP (Beta-255480) indicates the Fresno Series formed in alluvium deposited after the last glacial maximum (Tioga), and must correlate with the upper Modesto formation as defined, and not the lower Modesto as originally thought. A late Pleistocene-age for the Fresno soil is significant because it shows that similar strongly developed soils may also date to that time, while more weakly developed soils likely post-date the late Pleistocene.

A similar stratigraphic relationship was observed during a geoarchaeological study conducted in Caltrans District 10 to the north. As part of that study, a radiocarbon date of 20,200 cal BP (Beta-185710) was obtained from a well-developed buried soil exposed in a high terrace south of the Tuolumne River (Rosenthal and Meyer 2004b:66). This location is important because it lies near the original Modesto Formation type section and was mapped as an upper Modesto terrace deposit by Marchand and Allwardt (1981:60). The alluvium that forms the surface of the terrace bears a very weakly developed soil identified as the Tujunga. While previous researchers often associated the Tujunga Series with younger Holocene-age landforms (see Table 6), this soil also occurs on alluvial deposits mapped as late Pleistocene-age (Modesto) on the Chowchilla River fan (Helley 1966), the San Joaquin River fan (Janda and Croft 1967), and the Tuolumne River fan as noted above (Marchand and Allwardt 1981).

The maximum age of Tujunga series soils is constrained by a date of 1200 cal BP (OS-70225) obtained as part of the current study from the first buried soil (2Ab) exposed along the south bank of the Chowchilla River in Madera County (Figure 13:Location Madera 6). This date provides a maximum age for the Tujunga soil and indicates the upper Modesto deposit, as mapped along the Tuolumne River by Marchand and Allwardt (1981), was laid down less than 1,200 years ago, and that the underlying deposit was emplaced before the last glacial maximum (~22,000 cal BP), correlating with the lower Modesto formation as defined. This stratigraphic relationship suggests that late-glacial outwash did not cover this part of the Tuolumne River fan, and that the last major depositional episode did not occur until the latest Holocene, and only then after 20,000 years or more of landform stability (Rosenthal and Meyer 2004b:66).

Pleistocene-age land surfaces buried by middle or late Holocene-age deposits are not unique exceptions found in a few isolated areas, but occur at many other locations throughout the San Joaquin Valley and seem to represent part of a larger pattern of regional landscape evolution (Meyer 1996; Meyer and Rosenthal 1997, 2008; Rosenthal and Meyer 2004a, 2004b, 2009). More than a dozen radiocarbon dates from this and previous geoarchaeological studies confirm that late Pleistocene “Modesto-age” soils are buried at locations throughout the San Joaquin Valley. As shown in Figure 14, a date of 26,350 cal BP (OS-70230) from the glaciated eastern side of the San Joaquin River and one of 31,340 cal BP (OS-70220) from the unglaciated western side, both pre-date the last glacial maximum (“pre-Tioga”). Buried soils on both sides of the river, including below the Fresno Series, correspond closely with the age of the Tioga maximum (20,830 to 19,080 cal BP), suggesting that this time was marked by a period of relative landform stability, and not deposition. Most of the late Pleistocene buried soils, however, post-date the Tioga maximum by about 4,000 to 8,000 years (17,025 to 13,050 cal BP). Further, a revised Modesto soil-age relationship implies that major depositional episodes previously attributed to the Pleistocene are, in fact, Holocene in age (i.e., post-Modesto in age).

Radiocarbon Assessment of “Post-Modesto” Soil-Age Relationships A variety of surface soils in the San Joaquin Valley are generally associated with Holocene-age landforms, or sub-phases of the post-Modesto Formation as defined by Marchand and Allwardt (1981). But just as many “Modesto-age” soils are found on Holocene-age landforms, many of the most representative “post-Modesto” soils, like the Cajon, Chino, Hanford, Hesperia, Hilmar, Honcut, and Visalia series, also occur at the surface of landforms argued to be Pleistocene-age (see Table 6).

Marchand and Allwardt (1981) identified four main sub-units within the post-Modesto formation, which they designated with Roman numerals I, II, III, and IV from oldest to youngest. In the case of postModesto I, they explicitly associated soils of the Pachappa Series with these deposits, and observed that it was poorly represented at the surface and that related landforms were often isolated and/or surrounded by younger 501
Far Western 44 Transportation Enhancement Activities Program California Department of Transportation, District 6/9
Geoarchaeological Study
deposits where present. To constrain the age of the Pachappa Series, we obtained two radiocarbon dates from a cutbank exposed along upper Berenda Creek in Madera County (see Figure 13; Location Merced 8), where it is buried by a younger deposit—probably the Hanford series (Figure 15). A sample from the buried (2Ab) surface of the Pachappa soil produced a date of about 3200 cal BP (OS-72823), while a date of about 5230 cal BP (Beta255479) was obtained from a buried soil (3Btb) underlying the Pachappa (see photos in Chapter 4). Thus, the age of this signature post-Modesto I soil is now bracketed between 5200 and 3200 cal BP, suggesting it is at least late Holocene in age (i.e., <4,000 cal BP).

As for those soils found on both Pleistocene (Modesto) and Holocene (post-Modesto) land surfaces, radiocarbon dating shows that soils of the Cajon, Chino, Hanford, Hesperia, Honcut, and Visalia series are generally no more than 4,000 years old (cal BP), or late Holocene-age, and that soils such as the Hilmar and Tujunga series are less than 2,000 years old (cal BP), or latest Holocene-age (Table 7; Figure 15). Maximum ages were also obtained for soils such as the Cajon, Merced, Rossi, and Wunjey series, indicating that all are at least late or latest Holocene in age.

The only notable exceptions include a maximum early Holocene date of 9680 cal BP (Beta-246542) for the Piper series from Terminous Tract in the San Joaquin Delta (Meyer 2008b), and a minimum middle Holocene date of 5235 cal BP (Beta-255479) for the Greenfield series from Berenda Creek in Madera County.

Most importantly, soils most often associated with Holocene (post-Modesto) deposits in the study area (i.e., Arizo, Bear Creek, Foster, Grangeville, and Panoche series), are consistently less than about 4000 cal BP, or late Holocene in age, even at their 2-sigma maximum age ranges (Table 7; Figure 15).

CONCLUSIONS
Recent radiocarbon-dating has shown that alluvial deposits in central California, including those on the skirt of the western Sierra Nevada, are typically out of phase with glacial cycles. At the time of the glacial maximum (about 22,000 cal BP), landscape stability is represented by buried soils of this age in alluvial fans fronting the western Sierra Nevada and floodplains from the San Joaquin Valley proper. At the same time, pluvial lakes east of the Sierra Nevada were desiccated or in a recessional phase. These patterns clearly demonstrate that glacial advance does not correlate with intervals of widespread sediment transport or deposition. However, after the Tioga glaciers had receded, more than 15,000 years ago, depositional pulses are recorded by sequential buried soil profiles in the San Joaquin Valley, which correlates with pluvial lake high-stands east of the Sierra Nevada.

This suggests that there is some relationship between non-glacial conditions and sediment transport and deposition in central California. However, soil-age relationships described above offer compelling evidence that many landforms previously mapped as late Pleistocene-age are in fact capped by Holocene-age deposits with weakly to moderately developed soils, clearly demonstrating that widespread deposition was not simply an endPleistocene phenomenon. These relationships confirm that the magnitude and extent of Holocene sediment deposition was substantially greater and more pervasive than generally recognized in Central California. They also show that inconsistencies and problems with previous mapping affect our ability to understand the true age of many surface landforms, which has far-reaching implications for deciphering the Holocene landscape evolution and mechanisms driving landscape change.
502
Sonora
Merced
Madera
Fresno
Visalia
Salinas
Modesto
Hanford
Mariposa
Santa Ana
Riverside
Hollister
Bridgeport
Los Angeles
Bakersfield
Markleeville
Independence
San Bernardino
Inyo
Kern
Fresno
Tulare
San Bernardino
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Nye
Madera
Los Angeles
Merced
Monterey
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Tuolumne
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California
Nevada merald
a
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Stanislaus
Mineral
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Lyon
Ventur
a Sanluis Obispo Orange
Calaveras
Douglas
Santa Clara
1:1,500,000
0 10 20 30 40 50 Miles
Carbon 14 Sample Locality
District 6
District 9 Note: Localities numbered sequentially in each county; see Appendix B for details.

Monterey
Bay
Figure 13. Distribution of Radiocarbon Sample Localities in and near District 6/9.

Geoarchaeological StudyCalifornia Department of Transportation, District 6/9Transportation Enhancement Activities Program Far Western45 •
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Min. Cal BP
Cal BP - med. prob.

Max. Cal BP
Latest Pleistocene
Note: Samples identified by county "FRE," by site "-0257" and/or location, "Arroyo Hondo", and by stratigraphic position below the surface soil (4Bkb below Milham) [1] Rosenthal and Meyer (2004b); [2] Milliken and Young (2000) cal Years BP
FRE-0257, Arroyo Hondo (4Bkb below Milham)
MER, Detention Basin (3ABtb below Traver)
FRE-0257, Arroyo Hondo (3Bkb below Milham)
TUO, Tuolumne River (2Ab below Tujunga) [1]
KER, Salt Creek, S.R. 33 (3Ab below Panoche)
MAD, Chowchilla Canal (2ABtb below Fresno)
KER, Salt Creek, S.R. 33 (2Ab below Panoche)
MER, Detention Basin (2Ab below Traver)
KIN, Lemoore Air Station (2Ab of Lethent below Gepford) [2] KIN, Tulare Lake, Omaha Canal (2Ab of Lethent below historic lacustrine deposit) KIN, Tulare Lake, Omaha Canal (3Ab below Lethent)KIN, Tulare Lake, Omaha Canal (5Ab below Lethent) FRE, Tumey Gulch (5ABtk bbelow Guijarral)
Late Pleistocene
Older Pleistocene
Figure 14. Pleistocene Radiocarbon Dates from Buried “Modesto-Age” Soils in the San Joaquin Valley.

Transportation Enhancement Activities Program
California Department of Transportation, District 6/9
Geoarchaeological Study
47 Far Western
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* A-horizon buried where dated
Late Pleistocene
(Upper Modesto)
Latest Pleistocene
(Upper Modesto)
Early and Middle Holocene
(post-Modesto)
Late Holocene
Latest Holocene
(post-Modesto)
(post-Modesto)
cal Years BP
Traver
Lethent
Piper
Pachappa
Visalia
Hesperia
Chino
Hanford
Conejo
Cajon
Panoche
Hilmar
Arizo
Greenfield *
Atwater *
Pachappa *
Rossi
Arizo
Conejo
Hesperia *
Merced *
Cajon
Panoche
Wunjey *
Foster
Honcut
Bear Creek
Sacramento
Foster
Tujunga
Grangeville
Fresno
Mediam Probability (Minimum Age) 2-Sigma RangeMediam Probability (Maximum Age) 2-Sigma Range Figure 15. New Radiocarbon-Age Relationships of “Modesto” and Post-Modesto Soils in the Study Area.

Transportation Enhancement Activities Program
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Table 7. Previous and Revised Age of Surface Soils Associated with “Modesto” and “Post-Modesto” Deposits in the San Joaquin Valley.

SOIL SERIES
(CONTEXT)
DATES
(N=146) CAL BP 2-SIGMA CAL BP

PREVIOUS AGE(S), FORMATION, MEMBER, OR UNIT
[CORRELATE] REVISED AGE

POST-MODESTO SOILS
Grangeville (surface) 5 323 63-679 Holocene, Post-Modesto I, II, and III Latest Holocene Merced (surface) a
1 971 924-1057 Latest Pleistocene and Holocene, Upper Modesto and Post-Modesto I-II [Dos Palos]
Middle Holocene
Wunjey (surface) a 1 128 57-275 Latest Pleistocene, Upper Modesto Latest Holocene Tujunga (buried) 1 1217 1168-1279 Latest Pleistocene and Holocene, Upper Modesto and Post-Modesto I, II, III
Historical-Modern
Hilmar (buried) 3 1268 723-2073 Late Pleistocene, Lower Modesto Latest Holocene Panoche (surface) 5 585 398-665 Holocene, Post-Modesto II, [Patterson] Latest Holocene Panoche (buried) 4 1571 185-2992 Holocene, Post-Modesto II, [Patterson] Latest Holocene Arizo (surface) 13 828 285-2347 Holocene, Post-Modesto II [Post Palmdale I] Latest Holocene Arizo (buried) 14 1845 604-2592 Holocene, Post-Modesto II [Post Palmdale I] Latest Holocene Sacramento (buried) 1 2257 1692-2845 Holocene, Post-Modesto I-IV [Dos Palos] Latest Holocene Foster (surface) 2 1438 1313-1562 Holocene, Post-Modesto I, II, and III Latest Holocene Foster (buried) 3 3053 2014-3759 Holocene, Post-Modesto I, II, and III Latest Holocene

MODESTO SOILS
Cajon (surface) 39 873 272-1601 Latest Pleistocene, Upper Modesto [Upper Palmdale] Latest Holocene Cajon (buried) 7 2433 1674-3642 Latest Pleistocene, Upper Modesto [Upper Palmdale] Latest Holocene Bear Creek (buried) 3 2461 1891-2890 Holocene, Post-Modesto II Late Holocene Rossi (surface) 1 2615 2453-2765 Late Pleistocene, Lower Modesto Early Holocene Conejo (surface) 2 1189 1037-1340 Latest Pleistocene, Upper Modesto Latest Holocene Conejo (buried) 5 2640 1839-3320 Latest Pleistocene, Upper Modesto Late Holocene Hanford (buried) 4 2644 1131-3929 Latest Pleistocene and Holocene, Upper Modesto and Post-Modesto I, II, III
Late Holocene
Honcut (buried) 2 3184 2848-3519 Holocene, Post-Modesto I and II Late Holocene Chino (buried) 5 3622 2846-4397 Latest Pleistocene, Upper Modesto Late Holocene Atwater (surface)a 1 3637 3574-3693 Late Pleistocene, Lower Modesto [“pre-Tioga” dune sand] Latest Pleistocene Hesperia (surface)a 11 1045 295-3288 Latest Pleistocene, Upper Modesto Late Holocene Hesperia (buried) 2 3755 2246-5263 Latest Pleistocene, Upper Modesto Late Holocene Visalia (buried) 1 4089 3859-4300 Latest Pleistocene, Upper Modesto Late Holocene Pachappa (surface) a 1 3208 3050-3360 Late and/or Latest Pleistocene, Upper and/or Lower Modesto Middle Holocene Pachappa (buried) 1 5233 5052-5325 Late and/or Latest Pleistocene, Upper and/or Lower Modesto Middle Holocene Greenfield (surface) a 1 5233 5052-5325 Late and/or Latest Pleistocene, Upper and/or Lower Modesto Early Holocene Piper (buried) 1 9680 9550-9880 Latest Pleistocene, Upper Modesto Early Holocene Lethent (surface)a 4 13,670 13,394-
13,835
Late and/or Latest Pleistocene, Upper and/or Lower Modesto [San Luis Ranch]
Latest Pleistocene
Traver (buried) 1 15,490 15,158-
15,866
Late and/or Latest Pleistocene, Upper and/or Lower Modesto Early Holocene Fresno (buried) 1 19,079 18,920-
19,281
Late and/or Latest Pleistocene, Upper and/or Lower Modesto Latest Pleistocene Note: cal BP – Mean for multiple median probabilities; a Buried where dated. 507
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CHAPTER 4. AGE OF SURFACE LANDFORMS, REFINED SOIL

CHRONOSTRATIGRAPHY, AND MODEL OF LANDSCAPE EVOLUTION
The conflict of theories, leading, as it eventually must, to the survival of the fittest, is advantageous.
~ Grove Karl Gilbert (USGS Geologist 1879ñ1918)
Numerous geological studies conducted throughout California indicate that alluvial and colluvial landforms have undergone prolonged periods of stability, interrupted by episodes of widespread erosion and relatively rapid deposition. These cycles of landscape evolution are expressed as stratigraphic series of laterally extensive buried soils. Radiocarbon dates from these buried soils demonstrate that cyclical deposition and stability were on-going processes spanning the late Pleistocene and throughout the Holocene, recorded in glaciated and unglaciated drainages alike. These patterns appear to be best explained by broad changes in regional climate, rather than simply a response to glacial cycles. With this in mind, the following chapter begins by detailing a model of landscape evolution that provides a direct link between changes in precipitation, vegetative cover, and intervals of landscape stability and instability, explaining why roughly synchronous episodes of Pleistocene and Holocene landscape evolution are recorded throughout central California. This is followed by a new synthesis of landscape evolution in the Study Area based on the chronostratigraphic analysis of more than 2,400 radiocarbon dates, resolving many of the inconsistencies in soil-landform relationships inherent to earlier studies.

A CLIMATE-BASED MODEL OF LANDSCAPE EVOLUTION
Geomorphic studies conducted in basins of the western United States have shown that maximum sediment yields are typically produced when vegetation cover is reduced and precipitation is increased (Langbein and Schumm 1958). Such geomorphic thresholds are reached when the prevailing climate changes from dry to wet or wet to dry. Sediment yield drops sharply in either direction of this threshold due to decreased runoff at lower levels of precipitation and increased vegetation cover at higher levels (Bull 1964:37; Langbein and Schumm 1958; Ritter 1986). For example, Figure 16 illustrates the relationship between mean annual temperature, precipitation, and sediment yield using a mean annual temperature of 15 °C (60 °F). Under this temperature regime, maximum sediment yield is predicted at approximately 17-18 inches of annual rainfall because the type of vegetation developed under these conditions is the most conducive to water-related erosion (Langbein and Schumm 1958; Ritter 1986). Although sparse vegetation makes the ground surface highly susceptible to erosion, when annual precipitation falls below 17 inches, sediment yields decrease due to insufficient run-off. Similarly, when effective precipitation reaches above 18 inches, sediment yields are reduced by increased vegetation cover that protects and stabilizes hill slopes and other landforms.

The geologic record of central California suggests that threshold adjustments occurred periodically throughout the late Pleistocene and Holocene, and in many cases were regional in scope. These periods of landscape instability are strongly correlated with transitions reflected in the paleoclimatic record (e.g., Rosenthal and Meyer 2004a). Similarly, periods of both increased and decreased precipitation in central California correspond to intervals of widespread landform stability indicated by extended periods of soil formation during the late Pleistocene, early Holocene, and middle Holocene. The late Holocene geomorphic record is more variable, but also suggests that landscape changes were in large part related to fluctuations in regional precipitation and climate.

Because precipitation, vegetative cover, and topography strongly condition fluvial transport of sediment (e.g., Langbein and Schumm 1958), vastly different potential exists for erosive and depositional forces to have influenced the timing and nature of landscape evolution across the Study Area. Arid regions, such as the Mojave Desert, Great Basin, and eastern Coast Ranges, where vegetative growth has been sparse throughout the Holocene, would have consistently had more sediment available for transport than better-watered and -vegetated 509
1000
800
600
400
200
0 0 10 20 30 40 50 60 70
Mean Annual (Effective) Precipitation in Inches
Mean Annual Sediment Yield
(Tons Per Square Mile)
60 °F
Figure 16. Net Annual Sediment Yield in Relation to Precipitation.

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regions, such as the Sierra Nevada. When substantial rainstorms did occur in these arid regions, erosion, fluvial transport, and deposition was probably quite common, resulting in a very idiosyncratic geomorphic record, conditioned by the randomness of local precipitation.

In the Sierra Nevada, precipitation was always higher, resulting in greater vegetation cover which, in turn, served to blanket and bind local landforms, making them less susceptible to erosion and transport of sediment during periods of extreme rainfall. When substantial episodes of erosion and deposition did occur in the Sierra Nevada, it was likely the product of a convergence between changes in vegetative cover and precipitation. As a result, it is expected that sediment deposition in the Sierra Nevada and adjoining San Joaquin Valley would have been greatest during periods of climate change, and therefore would have been regionally synchronous and episodic.

Because arid regions of the Study Area always had reduced vegetative cover, and rainfall was always likely to have been reduced and sporadic due to the rainshadow effect of the Coast Ranges and Sierra Nevada, declines in precipitation due to large-scale climate changes should have had little effect on the geomorphic landscape.

However, increases in regional precipitation should have been a significant factor in the evolution of the geomorphic landscape in the arid regions too, resulting in depositional responses similar to those in better-watered portions of the Study Area. As a result, it is likely that major transitions in regional climate are linked to geomorphic responses both east and west of the Sierra Nevada. This, rather than glacial retreat per se, likely explains geomorphic responses recorded on both sides of the Sierra following the last glacial maximum and accompanying the Pleistocene-Holocene transition. It may also explain why cyclical patterns of deposition and landform stability are recorded in both glaciated and unglaciated drainages and continue from the late Pleistocene through the entire Holocene. As discussed in the following section, a climate change model also explains why these episodes of landscape evolution are roughly synchronous across the entire study area.

REFINED SOIL-AGE RELATIONSHIPS, CHRONOSTRATIGRAPHY,

AND THE AGE OF SURFACE LANDFORMS
As discussed in the previous chapter, the indiscriminate use of untested (i.e., undated) soil-age assignments has not only blurred and confused a fundamental distinction between Pleistocene and Holocene landforms, it has obscured many other important chrono-stratigraphic relationships as well. This has created serious problems for archaeological studies that must reconstruct former environmental conditions so that patterns of human land use, settlement, and the influence of subsequent landscape changes can be understood. As such, there is a clear need for a new synthesis of landscape evolution in south-central California that attempts to constrain the age of alluvial landforms and the soils formed on them specifically for the purposes of archaeological research and cultural resources management.

It is apparent that the central California landscape has been repeatedly altered and shaped by a complex sequence of large-scale environmental changes. Over the past 20,000 years, this region has experienced the effects of deglaciation, increased aridity, cycles of droughts and floods, as well as human-made changes associated with the historic-era (vegetation replacement, gold mining, and land reclamation). Widespread erosion of the uplands led to the formation of extensive depositional landforms in the lowlands, such as fans, floodplains, and natural levees. The presence of buried soils at the top of multiple alluvial sequences indicates that episodes of sediment deposition were relatively short (annual or decadal scales) compared to long periods of landform stability and soil formation that followed (centennial and millennial scales). Region-wide episodes of alluvial aggradation and stability were accompanied by localized changes in the position and size of stream and river channels, and presumably in the type and distribution of associated plant and animal habitats (e.g., dissected uplands, flood basins, riparian corridors, wetlands), which in turn influenced the location of human settlements. Since many substantial changes occurred during the time that humans first occupied this region, the following section reconstructs the evolution of the landscape by combining previous soil and geologic information with new data generated for this study.

To compensate for the previous lack of temporal control, 65 new radiocarbon dates were obtained from the Study Area (Table 8; Appendix B), and more than 2,400 previously reported radiocarbon dates were compiled into a regional database (provided in Appendix B). All dates and sample locations werelinked to digital soil survey 511
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data (i.e., SSURGO and STATSGO) in a GIS format (see discussion of database and mapping methods in Chapter 6, Buried Site Potential). Through a synthesis and analysis of these radiocarbon dates, this section presents evidence for a refined chrono-stratigraphic framework used to construct a new model of regional landscape change.

The discussion is divided into two parts, the first focuses on regions west of the Sierra Nevada, and the second on those parts of the Study Area located to the east. Both discussions are presented in chronological order from oldest to youngest.

SAN JOAQUIN VALLEY AND SIERRA NEVADA
Then shalt thou count to three, no more, no less.

Three shalt be the number thou shalt count,
and the number of the counting shalt be three.

Four shalt thou not count, nor either count thou two,
excepting that thou then proceed to three. Five is right out! ~ Monty Python and the Holy Grail
(Scene 33, Holy Hand Grenade of Antioch)
Older Pleistocene (>25,000 cal BP)
Before the last major advance of the Tioga glaciers began about 25,000 years ago, a considerable amount of sediment had already been stripped from the upper slopes of the western Sierra Nevada in response to uplift, channel cutting, and earlier cycles of glacial erosion and outwash (i.e., Tahoe and Tenaya). As a result, large alluvial fans emanating from glaciated and unglaciated drainages were deposited along the eastern side of the San Joaquin Valley and together formed a large pediment-plain (Figure 17 and Figure 18). The size and coarse texture of these older Pleistocene fans reflect the magnitude and geomorphic competence that was achieved during this time period. The nature and extent of older Pleistocene deposits preserved at the modern surface indicate that some large areas have remained relatively stable, while other segments have either been removed by erosion and/or buried by younger deposits, particularly near the axis of the San Joaquin Valley (Lettis 1982; Weissmann et al. 2003).

Many older Pleistocene landforms near the margins of the valley were subsequently incised and dissected by channel and gully erosion, while those near the center of the valley were buried by sediment. Faulting and tectonic uplift of some older Pleistocene deposits increased the pace of surface dissection and channel incision, resulting in the formation of highly eroded landforms like Wheeler Ridge in the southern San Joaquin Valley, and the Elk Hills and Kettleman Hills in the southwestern part of the valley; the latter is composed of uplifted early Pleistocene lakebed sediments (Tulare Formation).

In the glaciated watersheds of the Kaweah, Kern, Kings, Tulare, and San Joaquin rivers, channels in the upper (proximal or fan head) portions of the fans became deeply incised below the surrounding fan surface, effectively “locking” them into the general position they maintain today. A similar pattern of older Pleistocene fan deposition and subsequent fan-head entrenchment is found in virtually every unglaciated watershed along the eastern side of the valley, including Cottonwood, Deer, Dog, Fancher, Poso, Tejon, and Wahtoke creeks, and the Chowchilla, Fresno, Madera, and White rivers. However, no evidence of Tahoe-age or Tenaya-age glacial deposits have been found in the Tulare Lake Basin (Atwater et al. 1986; Davis 1999a), one of the valley’s primary depositional centers which, as noted in the previous chapter, may suggest the Kings River flowed northward at this time.

A series of much smaller fans is exposed along the valley’s western margin near the base of the hillslopes and mouths of every major stream that drains the Temblor and Coast ranges; the largest is found near Los Gatos, Panoche, and Little Panoche creeks. Because only the upper (proximal) portions of these fans tend to be exposed at the surface, central and lower (medial and distal) portions appear to be buried by younger deposits.

Dates from buried soils in three separate locations indicate that landforms of this age were buried by younger deposits between about 31,340 and 26,352 cal BP, centering on a mean age of about 29,345 cal BP 512
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Table 8. Summary of Radiocarbon Dates Obtained for This Study (Listed by Lab/Sample Number).

LAB OR
SAMPLE NO.

CALTRANS
DIST.

COUNTY, AREA OR SITE
NUMBER

DEPOSIT (TYPE) ADDITIONAL CONTEXTUAL INFORMATION MATERIAL DATED MIN.-MAX.

DEPTH CM
14C BP AND ERROR
AT 1-SIGMA
CAL BP
(MED. PROB.)
MIN.

CAL BP
MAX.

CAL BP
Beta-255479 6 MAD, Berenda Creek Buried soil (natural) 3Btb, in E cutbank, eroded top of Greenfield over Riverbank and below Pachappa; min-age for Greenfield Soil (SOM) 130-150 4570 ± 40 5233 5052 5325 Beta-255480 6 MAD, Chowchilla Canal Buried soil (natural) 2ABtb, east wall of canal below Fresno soil as mapped Soil (SOM) 310-330 15,900 ± 70 19,079 18,936 19,281 Beta-255481 6 FRE, N Russell Ave Buried soil (natural) 1.2 miles N of W Nees Ave, E of N Russell Ave, E wall of canal ~130 meters S of Third Lift Canal Soil (SOM) 30-40 4230 ± 40 4753 4627 4762 Beta-255482 6 FRE, Fresno Slough Buried soil (natural) 2Ab below Merced clay in cut W of RR-tracks, S of James Bypass, E of Fresno Slough Soil (SOM) 80-100 1060 ± 40 971 924 1057 Beta-255483 6 TUL, Tulare River Buried soil (natural) 2ABkb, in N bank of Tulare River channel below Colpien soil as mapped Soil (SOM) 280-290 7560 ± 40 8379 8315 8427 Beta-255484 6 KIN, Tulare Lake, Omaha
Canal
Buried soil (natural) 2Ab of Lethent below historical lacustrine deposits in S wall of irrigation canal (mapped as Lethent at surface) Soil (SOM) 70-80 11,930 ± 60 13,793 13,667 13,946 Beta-255485 6 KER, Garces Pit Buried soil (natural) 2ABkb (top of Garces) in S wall of detention basin below A/C soil, probably Panoche Soil (SOM) 50-70 1840 ± 40 1776 1695 1875 OS-67051 6 FRE-257, Arroyo Hondo Buried deposit (cultural) N-arroyo bank, ~5 m E of bridge, 12 m S of fence Charcoal 430-450 1700 ± 25 1603 1540 1634 OS-70215 6 FRE, Los Gatos Creek Buried soil (natural) Los Gatos Creek, west-side north bank, tree stump at base of terrace Wood (unknown) 1300-1300 4120 ± 40 4651 4528 4713 OS-70216 6 FRE-61, Wahtoke Creek Buried soil (natural) Wahtoke Creek at FRE-61, E bank, 2Ab Soil (SOM) 190-228 3480 ± 35 3759 3682 3841 OS-70217 6 KER, Salt Creek, S.R. 33 Buried soil (natural) S.R. 33 Salt Creek Gully, 2Ab Soil (SOM) 70-80 14,250 ± 75 17,026 16,585 17,461 OS-70220 6 FRE-257, Arroyo Hondo Buried soil (natural) Arroyo Hondo, northeast bank, 4Bkb Soil (SOM) 230-250 26,100 ± 150 31,340 30,896 31,784 OS-70221 6 FRE, Los Gatos Creek Buried alluvium (natural) Los Gatos Creek, north-side south bank, "black mat" Organic Sediment 1050-1050 4060 ± 90 4552 4423 4648 OS-70222 6 KER, Salt Creek, S.R. 33 Buried soil (natural) S.R. 33 Salt Creek Gully, west bank, 3Ab Soil (SOM) 120-140 16,600 ± 140 19,701 19,532 19,897 OS-70223 6 KIN-80, Tulare Basin Buried soil (natural) 2Ab w/cultural, burn layer above sand Charcoal (sunflower) 130-130 0 ± 10 a
-4 -5 0
OS-70224 6 KIN-80, Tulare Basin Buried soil (cultural) Shell and Charcoal layer at base of canal on west side Shell-f (freshwater) 240-250 8070 ± 80 8971 8694 9147 OS-70225 6 MAD, Chowchilla River Buried soil (natural) Chowchilla River, T1 below Tujunga, s bank, 2Ab Soil (SOM) 120-140 1260 ± 50 1217 1168 1279 OS-70226 6 MAD, Chowchilla River Buried soil (natural) Chowchilla River, T1, base of Tujunga, s bank, Cu Soil (SOM) 95-110 0 ± 10 a
-4 -5 0
OS-70227 6 MAD, Firebaugh Buried soil (natural) East bank of San Joaquin River, 2Ab below Foster series Soil (SOM) 75-80 2050 ± 70 2014 1926 2118 OS-70228 6 MAD, Firebaugh Buried soil (natural) East bank of San Joaquin River, 4Ab below Foster series Soil (SOM) 220-240 4570 ± 60 5286 5268 5323 OS-70229 10 MER, Detention Basin Buried soil (natural) 2ABtkb-horizon exposed in south wall of recently excavated basin, northwest of Ave. 26 and S. Bliss Rd. intersection Soil (SOM) 150-170 13,100 ± 150 15,158 15,490 15,866 OS-70230 10 MER, Detention Basin Buried soil (natural) 3ABtb-horizon exposed in south wall of recently excavated basin, northwest of Ave. 26 and S. Bliss Rd. intersection Soil (SOM) 260-280 21,900 ± 110 26,034 26,352 26,670 OS-70242 6 FRE, Fresno River Buried soil (natural) Fresno River, T2, w/n bank, 5Ab Soil (SOM) 400-420 7020 ± 260 7846 7606 8053 OS-70244 6 FRE, Fresno River Buried soil (natural) Fresno River, T2, N bank, 2Ab Soil (SOM) 130-150 3730 ± 170 4089 3859 4300 OS-70249 6 FRE, Panoche/Silver
Creek
Buried soil (natural) Panoche Creek, burn layer at base of south cutbank Soil (SOM) 1040-1050 6670 ± 150 7541 7433 7656 OS-70250 6 FRE, Panoche/Silver
Creek
Buried soil (natural) Panoche Creek, buried soil (2Ab) near top of south cutbank Soil (SOM) 120-140 4150 ± 130 4684 4521 4840 OS-70251 6 FRE-257, Arroyo Hondo Buried soil (natural) Arroyo Hondo #1, north bank, 3Bkb Soil (SOM) 170-190 17,650 ± 220 20,832 20,482 21,240 OS-70857 6 FRE-257, Arroyo Hondo Buried soil (natural) South cutbank, 2Ab Bone (elk) 165-180 0 ± 10 a
-4 -5 0
OS-71154 6 FRE, Fresno River Buried soil (natural) Fresno River, T2, N bank, 3Ab Soil (SOM) 315-330 4840 ± 20 5592 5581 5609 OS-71155 6 FRE, Fresno River Buried soil (natural) Fresno River, T2, N bank, 4Ab Soil (SOM) 340-360 6060 ± 25 6918 6849 6992 OS-71156 6 FRE, Los Gatos Creek Buried soil (natural) Los Gatos Creek, north bank, intact root in lowest Ab Root 1230-1350 3930 ± 25 4367 4287 4437 OS-71157 6 FRE, Los Gatos Creek Buried alluvium (natural) Los Gatos Creek, base of Excelsior terrace, T2 Wood (pine cone) 530-530 3880 ± 20 4331 4246 4409 OS-71158 6 FRE, Little Panoche Creek Buried soil (natural) 2Ab in south bank below Vernalis series Soil (SOM) 140-160 5330 ± 25 6104 5999 6193 OS-71160 6 FRE, Panoche/Silver
Creek
Buried soil (natural) Panoche Creek, burn layer near center of south cutbank Soil (SOM) 665-665 4330 ± 20 4872 4846 4893 OS-71197 6 FRE, Little Panoche Creek Buried soil (natural) 5(?)Ab in south bank at base of Vernalis terrace Soil (SOM) 490-510 7390 ± 30 8236 8163 8326 OS-71198 9 INY, Owens Lake, south Surface deposit (natural) Packrat midden from incised buried fan north of Highway 178 (178.1) Packrat Midden 0-1 200 ± 15 168 148 188 OS-71199 9 INY, Owens Valley,
Hearth Gully
Buried soil (cultural) Buried hearth in inset fan west of S.R. 170 (190.1) Charcoal 50-50 405 ± 20 488 451 510 OS-71200 6 MAD, Cottonwood Creek Buried soil (natural) 2Ab in west bank of T2 terrace below Hanford series Soil (SOM) 60-80 1210 ± 20 1131 1064 1179 OS-71201 6 MAD, Firebaugh Buried soil (natural) East bank of San Joaquin River, 3Ab below Foster series Soil (SOM) 110-130 3160 ± 20 3385 3355 3415 OS-71202 5 SBN, Panoche Creek Buried soil (natural) Base of Panoche Valley floodplain, ~5Ab in south bank, Patterson Alluvium of Lettis 1982 Soil (with charcoal) 640-660 2820 ± 25 2859 2920 2990 OS-71213 6 FRE, Little Panoche Creek Buried soil (natural) From 4ABtb paleosol at base of west bank, Upper San Luis Ranch? Soil (SOM) 420-440 8390 ± 25 9440 9399 9483 OS-71315 6 MAD, Cottonwood Creek Buried soil (natural) 3Abtb in west bank at base of T2 Hanford terrace Soil (SOM) 150-170 1930 ± 15 1878 1858 1902 OS-71316 6 MAD, Cottonwood Creek Buried soil (natural) 2Ab of Atwater series in south bank of T3 terrace below Hanford series as mapped Soil (SOM) 80-100 3390 ± 25 3637 3574 3693 513
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Table 8. Summary of Radiocarbon Dates Obtained for This Study (Listed by Lab/Sample Number) continued.

LAB OR
SAMPLE NO.

CALTRANS
DIST.

COUNTY, AREA OR SITE
NUMBER

DEPOSIT (TYPE) ADDITIONAL CONTEXTUAL INFORMATION MATERIAL DATED MIN.-MAX.

DEPTH CM
14C BP AND ERROR
AT 1-SIGMA
CAL BP
(MED. PROB.)
MIN.

CAL BP
MAX.

CAL BP
OS-71317 5 SLO, Cuyama River Buried deposit (cultural) Burn layer (hearth?) in south bank of gully, north of river, south of S.R. 166 Charcoal 250-260 175 ± 15 167 185 217 OS-71414 6 FRE-257, Arroyo Hondo Buried soil (natural) Arroyo Hondo, northeast bank, 4Bkb below Millham (1 of 2 dates on same sample?) Soil (SOM) 230-250 14,450 ± 60 17,365 16,909 17,789 OS-71416 6 MAD, Cottonwood Creek Buried soil (natural) 3Abtb in south bank of T3 terrace below Atwater series (too young?) Soil (SOM) 210-230 3620 ± 20 3929 3867 3982 OS-72582 6 FRE, San Joaquin River Buried soil (natural) 2Ab in south cutbank below Wunjey soil as mapped (T3? Terrace) Charcoal 170-190 130 ± 30 128 57 275 OS-72583 9 INY, Owens Lake, south Lacustrine (natural) 5Cg, Strat II, upper lacustrine in E wall of gully Soil (SOM) 180-190 9310 ± 50 10,514 10,371 10,609 OS-72584 9 INY, Owens Lake, south Lacustrine (natural) 6Cg, Strat I, lower lacustrine in E wall of gully Soil (SOM) 220-240 9230 ± 55 10,396 10,250 10,522 OS-72698 9 INY, Owens Valley,
Horton Creek
Buried soil (natural) 2Ob, W wall of T2 terrace below site/soil buried by Torriofluents Peat (peaty clay) 105-115 4490 ± 35 5167 5038 5297 OS-72699 6 KIN, Tulare Lake, 10th St
Canal
Buried soil/lacustrine
(natural)
2Akb, desiccated lake soil, W wall of 10th St. Canal, below Tulare clay Soil (SOM) 100-130 7530 ± 40 8358 8299 8411 OS-72700 6 KIN, Tulare Lake, 10th St
Canal
Lacustrine (natural) 3Cg, uppermost lacustrine in W wall of 10th St. Canal, below Tulare clay Soil (SOM) 160-190 8970 ± 40 10,161 10,118 10,230 OS-72701 6 KIN, Tulare Lake, Omaha
Canal
Buried soil (natural) 3Ab, in S wall of irrigation canal below Lethent soil as mapped Soil (SOM) 135-145 11,800 ± 85 13,656 13,435 13,820 OS-72702 6 KIN, Tulare Lake, Omaha
Canal
Buried soil (natural) 5Ab, in S wall of irrigation canal below Lethent soil as mapped Soil (SOM) 165-175 11,550 ± 85 13,394 13,241 13,614 OS-72752 9 INY, Owens Lake, south Lacustrine (natural) 2Cg, uppermost buried lacustrine shell/death bed, south lakeshore Bone (fish) 370-400 7440 ± 75 8263 8154 8395 OS-72794 6 KER, Kern River Terrace Buried soil (natural) 2Ab below Hesperia as mapped, N-wall of T3 terrace, north of river and county road Soil (SOM) 160-170 2270 ± 70 2246 2157 2262 OS-72823 6 MAD, Berenda Creek Buried soil (natural) 2Ab of Pachappa series in E cutbank above Greenfield (Pachappa mapped at surface incorrect) Soil (SOM) 80-100 3010 ± 120 3208 3059 3360 OS-72826 9 INY, Owens River Bluff Buried soil (natural) 2Cu, carbon layer, S bank of T3 terrace below sand layer mapped as Mazourka-Eclipse; same age as lithofacies 4a of Bacon
Soil (SOM) 150-160 12,650 ± 220 14,873 14,292 15,232
OS-72830 6 FRE, Tumey Gulch Buried soil (natural) 2Abkb in N bank of gulch below Millham soil as mapped Soil (SOM) 80-100 8790 ± 50 9816 9602 9955 OS-72831 6 FRE, Tumey Gulch Buried soil (natural) 3Ab near top of south cutbank below Guijarrel soil as mapped Soil (SOM) 60-70 22,400 ± 200 26,926 26,412 27,440 OS-72832 6 FRE, Tumey Gulch Buried soil (natural) 5Abtkb (?), base of south cutbank below Guijarrel soil as mapped Soil (SOM) 610-620 11,150 ± 65 13,051 12,926 13,184 OS-72855 9 INY, Owens Lake, south Buried soil (natural) 3Ab, Strat. IV, E wall of gully, stratum underlies buried hearth Soil (SOM) 120-130 5950 ± 40 6778 6677 6883 OS-73065 6 TUL, Tulare River Buried soil (natural) 3Abkb, in N bank of Tulare River channel below Colpien soil Soil (SOM) 330-350 7010 ± 50 7848 7722 7946 OS-73445 6 KIN, Tulare Lake, Omaha
Canal
Surface deposit Whole shell in growth position at contact of Cu horizon with 2Ab Shell-f (Anodonta) 50-60 200 ± 20 177 145 215 OS-73446 6 KIN-32, Witt Locality Buried lacustrine (natural) Snail from intact dune sand 2A/Cox contact below disturbed sand with paleo-artifacts, N bank of Blakely Canal Shell-f (gastropod) 45-50 2250 ± 30 2232 2156 2266 Notes: a
Arbitrary 1-Sigma of ±10 years used to calibrate “modern” dates; SOM – Soil Organic Matter; Min – Minimum; Max – Maximum; Med. Prob. – Median probability.

515
516
Pine Flat
Reservoir
Goose
Lake Bed
Lake
Crowley
Millerton
Lake
Lake
Success
Shaver
Lake
Eastman
Lake
Hensley
Lake
Huntington
Lake
Deer Creek
Poso Creek
Owens River
Kern River
Amargosa River
argosa River Am
Tule River
Kings River
West Walker River
Dry Creek
Dry Creek
Fresno River
ough Fresno Sl
San Joaquin
River
Ch
owchilla
River
Mono
Lake
Owens Lake
Isabella
Lake
Inyo
Kern
Fresn
o
Tulare
Kern
Mono
Madera
Kings
Kings
Fresno
Tulare
Fresno
Inyo
Inyo
San
Bernadino
LtH
OP
LH
EH
OP
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LtH
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LH
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Compiled from Soil Survey Geographic Database and U.S. General Soil Map coverages produced by the Natural Resource Conservation Service.
0 10 20 30 40
Miles
0 25 50 75 100
Kilometers
Water
Artificial Cut and Fill
Historical and ModernLatest HoloceneLatest Holocene VolcanicLate HoloceneHolocene Volcanic (undivided) Middle HoloceneEarly HoloceneEarly Holocene VolcanicLatest PleistoceneLate PleistoceneOlder PleistocenePre-Quaternary H2O
HacfHmLtHLtHvLHHvun
MHEHEHvLtPLPOPpQ
Figure 17. Depositional Landforms and Buried Archaeological Potential in Caltrans District 6/9.

Transportation Enhancement Activities Program
California Department of Transportation, District 6/9
Geoarchaeological Study
59 Far Western
11~111
1111~1
517
518
Calwa
Biola
Malaga
Madera
Kerman
Friant
Fresno
Clovis
Rolinda
Raymond
OíNeals
Mendota
Herndon
Berenda
Pinedale
Coarsegold
Chowchilla
SanJoaquinRiver
Chowchil al River
Fre
ns
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Latest HoloceneLatest Holocene VolcanicLate Holocene
Holocene Volcanic (undivided)Middle HoloceneEarly Holocene Early Holocene VolcanicLatest PleistoceneLate Pleistocene Older PleistocenePre-QuaternaryHighway 0 2 4 Miles
For greater resolution and visual clarity, please refer to GIS database.

Figure 18. Older Pleistocene Fans Emanating from Glaciated and Unglaciated Drainages along the Eastern San Joaquin Valley.

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(Table 9). The oldest of these (31,340 cal BP, OS-70220) was obtained for this study from a well- developed buried soil (4Bkb) exposed in the bank of Arroyo Hondo Creek in western Fresno County (Figure 19), where the surface soil is mapped as Millham series. The youngest date (26,352 cal BP, OS-70230) was likewise obtained for this study from a well-developed buried soil (3ABtb) exposed in a recently excavated detention basin near the Madera/Merced county line where the surface soil is mapped as Traver series (Figure 19). The remaining three dates were obtained from buried soils along the Cuyama River in eastern San Luis Obispo County by Delong and Arnold (2007), where the Panoche-series soil is mapped at the surface. The age and nature of these buried soils suggest that the inter-glacial period between the Tahoe/Tenaya and Tioga glaciations was dominated by land stability and soil formation.

Table 9. Summary of Radiocarbon-Dated Buried Soils from Study Area by Time Periods.

OLDER

PLEISTOCENE
LATE

PLEISTOCENE
LATEST

PLEISTOCENE
EARLY

HOLOCENE
MIDDLE

HOLOCENE
LATE

HOLOCENE
LATEST

HOLOCENE
Minimum cal BP 26,352 15,029 11,624 7085 4089 2014 128
Mean cal BP 29,343 18,525 12,955 9081 5456 2913 1075
Maximum cal BP 31,340 20,832 13,835 11,321 6994 3929 1985 Std. Dev. (years) 2211 2133 816 1188 896 625 526
Sample Count (n=152) 5 7 11 30 25 25 49
Percent of Total 3.3% 4.6% 7.2% 19.7% 16.4% 16.4% 32.2% Late Pleistocene (~25,000 to 15,000 cal BP)
During the last glacial maximum, the growth and movement of glacial ice was accompanied by intense weathering and mechanical erosion that stripped and transported large amounts of rock and other coarse sediments into the upper reaches of each glacial drainage, resulting in the deposition of glacial till, terminal and lateral moraines, and outwash terraces (Burke 2003; Gillespie and Zehfuss 2004; Kaufman et al. 2004; Matthes 1960; Wahrhaftig 1984; Wahrhaftig and Birman 1965). These processes also produced fine-grained sediments that were carried down slope on an almost continual basis by seasonal melt water, and more occasionally during periodic flood events caused by episodes of rapid melting, increased precipitation runoff, and/or failures of icedams or morainal ridges.

While much of this sediment presumably made its way to the valley floor, buried soils dated between about 20,000 and 19,000 cal BP on the Tuolumne River fan and within the axial San Joaquin River basin indicate that landform stability, soil formation, and channel incision prevailed between about 25,000 and 20,000 cal BP as the ice sheet advanced and reached its maximum extent. This suggests that most channels were not filled and overwhelmed by the initial pulse of glacial outwash, but were largely able to contain these sediments which were either deposited in enclosed basins, such as Buena Vista and Tulare lakes (Atwater et al. 1986), or were removed (“flushed”) from the valley floor via the axial San Joaquin River. Though the channels were apparently large enough and/or competent enough to contain and transport initial loads of outwash, after 20,000 to 19,000 cal BP the amount of sediment appears to have increased and essentially exceeded the carrying capacity of these channels, particularly in the lower reaches of most drainages. As a result, most of the outwash associated with deglaciation filled existing basins and channels prior to spreading out laterally over the surface of adjacent fans and floodplains (Weissmann et al. 2003; Weissmann et al. 2005).

Radiocarbon evidence suggests that the initial depositional pulse was completed in 2,000 years or less, probably between about 18,500 and 16,500 years ago, as indicated by a mean age of 18,525 cal BP from seven well-developed buried soils at separate location in the Study Area (Table 9). A soil buried by the Traver series near the Merced/Madera county line produced the youngest of these dates (15,500 cal BP). The 2,000-year time frame for deposition is consistent with geomorphic models that show the release and reworking of glacially conditioned sediment is usually exhausted within 2,000 years or less (Ballantyne 2002a, 2002b). These dates also confirm that late Pleistocene-age landforms were buried in valleys west of the Sierra crest, with the oldest dating to 20,830 cal BP (OS-70251) at Arroyo Hondo Creek in western Fresno County (Figure 20). From this it appears that 520
Buried Soil Exposed in Wall of Detention
Basin, Near Madera/Merced County Line Arroyo Hondo Creek Bank Exposure, Fresno County Overview Detention Basin to Northwest,
Near Madera/Merced County Line
Truncated Hardpan (2Btkqmb) in South Bank
of Kings River Near Reedly, Kings County
Very Well-Developed Soils at Madera Lake,
View to West, Madera County
3Bkb - 20,482 cal BP
(OS-70251)
4Bkb - 30,896 cal BP
(OS-70220)
Truncated Hardpan (3Btkqmb) Exposed in South Bank
Millham series
of Cottonwood Creek, Madera County
surface soil
3Bkb
4Bkb
3Bkb
4Bkb
Hanford series
surface soil
2ABtkb - 15490 cal BP
(OS-70229)
3ABtkb - 26352 cal BP
(OS-70230)
Traver series surface soil
Hanford series
surface soil
2Btkqmb
3Btkqmb
2ABtkb - 15490 cal BP
(OS-70229)
3ABtkb - 26352 cal BP
(OS-70230)
Figure 19. Selected Views of Older Pleistocene Deposits in the San Joaquin Valley.

Transportation Enhancement Activities Program California Department of Transportation, District 6/9 Geoarchaeological Study
63 Far Western
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Detail of 2ABtb Sample (above);
Fossil bone (below), Chowchilla
Canal, Madera County
Overview of Deposits Exposed in West Bank of
Salt Creek Near State Route 33 in Kern County
Truncated Fresno Series (2Btkqmb) Overlain by
Holocene-Age Deposits, Chowchilla Canal, Madera County
Overview of Deposits Exposed in East Bank
of Chowchilla Canal, Madera County
2Ab - 17,026 cal BP
(OS-70217)
Fresno series surface soil
Sample Location in West Bank
of Salt Creek, Kern County
Deposits Exposed in East Bank of
Chowchilla Canal, Madera County
Soil (2ABtb) Below Fresno Series in East
Bank of Chowchilla Canal, Madera County
2Btkqmb
Fresno series
surface soil
Panoche series surface soil
3Ab - 19,701 cal BP
(OS-70222)
2ABtb - 19,079 cal BP
(Beta-255480)
Chino series surface soil
Figure 20. Selected Views of Late Pleistocene Deposits in the San Joaquin Valley.

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landscape elements relaxed to a state of non-deposition and relative stability by the time the Tioga glacial cycle was completed, which is consistent with the model of paraglacial landscape response proposed by Ballantyne (2002a, 2002b).

It is both telling and significant that late Pleistocene-age landforms are not nearly as well represented on the San Joaquin Valley floor as older Pleistocene landforms, but are instead relatively small and isolated. The largest and most extensive late Pleistocene surface deposits lie north and south of the San Joaquin River, just east of the valley’s active depositional center (Figure 21). Other sizable areas occur along the valley’s eastern side between the towns of Dinuba and Porterville, where these deposits form moderate-size alluvial fans that originate near the base of older Pleistocene fans (see Figure 17). However, the overall paucity of such surfaces suggests that either the magnitude and extent of late Pleistocene deposition have been greatly overestimated, post-glacial erosion has gone largely unrecognized and underappreciated, or landforms from this period were largely buried by younger sediments, in which case the amount and distribution of post-glacial deposits (i.e., Holocene) have been greatly underestimated and under-reported.

Latest Pleistocene (15,000 to 11,500 cal BP)
The environmental transition from glacial to non-glacial conditions brought with it fundamental transformations in plant and animal communities and substantial alterations in hydrologic and geomorphic systems that promoted landform instability in glaciated and unglaciated areas alike. The transition is marked by a series of relatively rapid climatic fluctuations that resulted in the advance and retreat of Recess Peak glaciers, between about 14,200 and 13,100 cal BP, and an overall reduction in temperature during the Younger Dryas cooling interval, between about 12,900 and 11,500 cal BP. The Recess Peak glaciation was, however, much smaller and short-lived than the previous Tioga glacial cycle, and the environmental influence of the Younger Dryas was also relatively short and subtle overall (Porinchu et al. 2003; Potito et al. 2006). This “transition” does not represent a unidirectional shift in environmental conditions as a whole, but is characterized by greater climatic variability and more heterogeneous responses that mark a period of increased environmental disequilibrium. This likely accelerated the rate of erosion and deposition as landforms and associated vegetation attempted to adjust to rapidly fluctuating conditions. As a result, latest Pleistocene-age landforms are even more prevalent and widely represented at the surface of the San Joaquin Valley floor than late Pleistocene-age landforms.

The largest and most continuous areas of latest Pleistocene surface deposits are found in and around the Tulare Lake Basin, which includes the lower Los Gatos Creek fan (i.e., “Lethent fan”) to the northwest, and the lower portions of other east-side fans to the southwest, with Buttonwillow Ridge and Semi Tropic Ridge being part of the latter (Figure 22). Smaller and more discontinuous deposits occur along the valley’s western margin, where they form alluvial fans, and just east of the Elk Hills where the lower Kern River fan appears to have blocked (“dammed”) the north end of Buena Vista Lake Basin (see Figure 17).

Within the study area, 11 radiocarbon dates from latest Pleistocene-age buried soils range from about 13,835 cal BP (Beta-137204) to 11,625 cal BP (GX-13338), with a mean age of 12,955 cal BP. The majority (~54.5%), however, form a distinct cluster between about 13,900 and 13,000 cal BP (see Table 9). Among this group are buried soils from wide-spread locations including Nichols Meadow in Madera County (Koehler and Anderson 1994), Boggy Meadow in Tulare County (Wood 1975) the Sierra Foothills near Sonora (i.e., the Greenstone site [TUO-4557] in Meyer et al. 2008; Rosenthal 2008) and the Cuyama River in eastern San Luis Obispo County (Delong and Arnold 2007). Also relevant for this period is a date of 13,570 cal BP (Beta-14299) from basal channel deposits in the Stanislaus River Canyon (Peak and Crew 1990), which indicates a net decrease in runoff and waterflow occurred after that time.

Five latest Pleistocene dates were obtained from the western (distal) part of the Los Gatos Creek alluvial fan which lies near the center of the San Joaquin Valley in Fresno and Kings counties (Figure 22), one from a previous study (Milliken and Young 2000) and four specifically for this study. This fan is mapped in the Lethent soil series and extends around the northwestern side of Tulare Lake Basin where it appears to mark the lake’s outer limit. To help determine the age of the Lethent fan, dates were obtained from three subsurface strata exposed along Omaha Canal Road, near the lake’s former northwestern shore (Figure 23). 523
Firebaugh
San Joaquin River
Eastside Bypass
Berenda Slo gu h
BerendaCreek
Dry Creek
Road 9
Avenue 7
Avenue 14
Avenue 7 1/2
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Dairyland
Fresno County
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Merced County
WaterArtificial Cut and FillHistorical and Modern
Latest HoloceneLatest Holocene VolcanicLate Holocene
Holocene Volcanic (undivided)Middle HoloceneEarly Holocene Early Holocene VolcanicLatest PleistoceneLate Pleistocene Older PleistocenePre-QuaternaryHighway 0 1 2 Miles
For greater resolution and visual clarity, please refer to GIS database.

Figure 21. Late Pleistocene Fan and Basin Deposits in the Eastern San Joaquin Valley.

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524
Huron
Lanare Camden
Avenal
Lemoore
Coalinga
Stratford
Riverdale
Kettleman City
Los Gatos Creek
Kings River
Tulare Lake Bed
Fresno Slough
South Fork Kings River
Kings County
Fresno County
Lethent
Fan
Gatos Creek, Los
Kings River
Cantua Creek
Warthan Creek
Tule River
Jacalitos Creek
White Creek
South Fork Kings River
Mud Run
Salt Creek
Oil Creek
Jasper Creek
Torcido, Arro
Vadoso, Ar
yo
royo
Armona
Pond
Wasco
Sh
Lost Hills
Devils Den
Allensworth
Buttonwillow
San Luis Obispo
County
Kern County
Kings County
Buttonwillow Ridge
Semi Tropic Ridge
Poso Creek
Bitterwater Creek
Santos Creek
Salt Creek
Zemorra Creek
Carneros Creek
Yeg uas Creek
Media Agua
Creek
Carnaza Creek
Packwood Creek
Kern County
Tulare County
San Luis
Lerdo Hwy
Bitterwater Rd
Lerdo Hwy
0 2 4 Miles
0 2 4 Miles
Water
Artificial Cut and Fill
Historical and Modern
Latest Holocene
Latest Holocene Volcanic
Late Holocene
Holocene Volcanic (undivided)
Middle Holocene
Early Holocene
Early Holocene Volcanic
Latest Pleistocene
Late Pleistocene
Older Pleistocene
Pre-Quaternary
Highway
Calders
Corner
Fruitvale
Gosford
Kern
City
Figure 22. Latest Pleistocene Fan and Basin Deposits in the Western (top) and Eastern (bottom) San Joaquin Valley.

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525
Overview of Omaha Canal to East, Sample
Location Near Truck on Right, Kings County
Tulare Lake Basin
5ABtkb
5ABtkb - 13,051 cal BP
(OS-72832)
Deposits Exposed in South Bank of
Tumey Gulch, Fresno County
Detail of 5ABtkb Horizon Near Base of
South Bank in Tumey Gulch, Fresno County
Guijarrel series surface soil
Overview of Sample Location,
South Bank of Omaha Canal, Kings County
Detail of Lethent Fan Sample Location,
South Bank of Omaha Canal, Kings County
2Ab - 13,793 cal BP
(Beta-255484)
3Ab - 13,656 cal BP
(OS-72701)
5Ab - 13,394 cal BP
(OS-72702)
4Ab
2 meters
Historic-era Lacustrine
Deposit
AC - 177 cal BP
(OS-73445)
4Ab
2Ab - 13,793 cal BP
(Beta-255484)
Figure 23. Selected Views of Radiocarbon-Dated Latest Pleistocene Deposits in the San Joaquin Valley.

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It was found that the surface of the Lethent fan in this location is buried by a deposit of lacustrine clay that dates about 175 cal BP (OS-73445) based on a freshwater shell date of 200 ± 20 14C BP (no local reservoir correction applied). Soil samples from the buried Lethent fan surface and from two more deeply buried soils (3Ab and 5Ab) produced dates that range from about 13,795 to 13,395 cal BP (Beta-255484 and OS-72702, respectively). Although the samples are in reversed stratigraphic order (see Figure 23), it is evident that multiple episodes of deposition occurred on the distal part of the Lethent fan during the latest Pleistocene, and that the fan subsequently remained stable until the early Historic-era when it was finally capped by lacustrine sediment. The latter finding is important because it suggests that Tulare Lake reached its highest stand(s) during the latest Holocene to Historic-era, and not during the late Pleistocene or early Holocene as suggested by Atwater et al. (1986) and Negrini et al. (2006), respectively.

Notably, a similar date of 13,050 cal BP (OS-72832) was obtained from a well-developed soil (5ABtkb) buried by more than six meters (20 feet) of alluvium below the surface of the Tumey Gulch fan in western Fresno County (see Figure 23). This buried soil and those from the Lethent fan offer compelling proof that large amounts of sediment were delivered to the valley floor in the latest Pleistocene, and that a substantial part of this sediment was derived from the unglaciated western side of the valley.

The age and nature of these deposits suggest that land stability, soil formation, and channel incision generally prevailed during the time of the Recess Peak glacial advance, as landscape elements continued to relax from glacial conditions. By the time of the Recess Peak de-glacial phase, between about 13,600 and 13,100 cal BP, evidence shows that sediments began to accumulate within high elevation meadows, major river canyons, and at low elevations as alluvial fan and basin deposits on the San Joaquin Valley floor (see Figure 23). The stratigraphic sequence derived from the Lethent fan demonstrates that alluvium was being deposited in the Tulare Basin during the time that a purported “gap in sedimentation” or major erosional event is recognized elsewhere in the basin (Atwater et al. 1986; Davis 1999a). Lacustrine deposits that overlie distal parts of the Lethent fan suggest that earlier high lake stands did not attain the elevations reached during the latest Holocene to Historicera (Negrini et al. 2006), further indicating that the history of Tulare Lake is out of phase with lake basins in eastern California.

It appears that environmental change during the last-half of Pleistocene-Holocene transition (~13,500 to 12,500 cal BP) was sufficiently rapid, intense, and widespread to destabilize landforms and generate a major pulse of deposition. The very presence of buried latest Pleistocene-age landforms indicates that many were subsequently overlain by younger Holocene-age deposits. A comparison of latest Pleistocene radiocarbon dates from buried and surface contexts illustrates that only about one-third (~33%) of dated late Pleistocene-age deposits occur at the present surface (Figure 24).

Early Holocene (11,500 to 7000 cal BP)
As the Pleistocene gave way to the Holocene, the Younger Dryas cooling interval ended and the transition from glacial to non-glacial conditions came to a close. Unlike the variability of the latest Pleistocene, the early Holocene marks a unidirectional shift toward warmer and drier conditions that was more homogeneous overall. As the warming and drying progressed incrementally, it reduced the vegetative cover on the landscape and caused many lakes, marshes, and springs to contract or disappear altogether, which forced associated plant and animal communities to adjust accordingly. As a consequence, the surface of most pre-existing landforms remained relatively stable and subject to soil formation as the rate of landscape change slowed. Reduced amounts of runoff concentrated the flow of water within existing channels, and caused many to become deeply incised and/or to migrate and erode laterally. This likely destabilized landforms adjoining channels, making them vulnerable to bank undercutting, slope bank failures, and head-ward gully erosion. As these processes continued, large amounts of sediment were either transported through the channels, or were made available for later transport. Thus, erosional and depositional processes became more localized during this time as the loci of both were shifted to more discrete segments of the landscape.

The limited distribution of early Holocene-age landforms at the surface of the valley floor (see Figure 17), and the number and extent of early Holocene-age buried landforms reflect this pattern. Surface deposits of 527
-47
-8 -10
-14
-96 -98
-95
-124
-100%
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0%
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-60%
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Latest Holocene
(2000-0 cal BP)
Late Holocene
(4000-2000 cal BP)
Middle Holocene
(7000-4000 cal BP)
Early Holocene
(11,500-7000 cal BP)
Latest Pleistocene
(15,000-11,500)
Percent
(per period)
Percent
(per period)
Surface Natural Contexts (n=158)
Buried Natural Contexts (n=460)
Surface Cultural Contexts (n=480)
Buried Cultural Contexts (n=87)
13 14
37 416
-55
Latest Holocene
(2000-0 cal BP)
Late Holocene
(4000-2000 cal BP)
Middle Holocene
(7000-4000 cal BP)
Early Holocene
(11,500-7000 cal BP)
23 15 18
97 5
Figure 24. Count and Percent of Buried and Surface Natural (top) and Cultural (bottom) Contexts by Major Time Periods.

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this age are most extensive and continuous north and south of the lower San Joaquin River, just east of the valley’s central trough (Figure 25) and on the central (medial) part of fans formed along the lower Kaweah and Tulare rivers, just east of Tulare Lake (see Figure 17). Small surface deposits are also found on the central (medial) part of the Kings River fan, and around the margins of the Kern/Buena Vista Lake basin, at the San Joaquin Valley’s southern end. This distribution clearly shows that most early Holocene surface deposits occur on the east side of the valley where they tend to form the central or lower parts of alluvial fans, or lie along the margins of basins such as Fresno Slough and Kern/Buena Vista Lake.

At least 30 early Holocene dates have been obtained on buried soils from locations in and near the Study Area. These dates range from about 11,320 cal BP (GX-13339) to 7085 cal BP (Beta-170151), with an overall mean age of about 9080 cal BP (see Table 9). Nearly three-quarters (n=22, 73%) fall between about 9800 and 7500 cal BP, and more than one half (n=17, 56.6%) occupy smaller clusters of about 9800 to 9300 cal BP and about 8300 to 7800 cal BP (Figure 26). These originate from a number of diverse environmental settings, including high elevation meadows in the Sierra Nevada (Koehler and Anderson 1994; Moratto 1984; Peak and Neuenschwander 1991; Wood 1975), alluvial fans and low-angle hillslopes in the Sierra Foothills (Dillon 1992; Meyer and Dalldorf 2004; Meyer et al. 2008), and alluvial fans, floodplains, and basins in the San Joaquin Valley (Davis 1999a; Negrini et al. 2006; Young 2003).

A date from freshwater mussel shell obtained for this study (8070 ± 80 BP, or 8971 cal BP, OS-70224) at archaeological site KIN-80 is associated with a discrete layer of cultural material (i.e., shell, charcoal, burnt bone, and chert flakes) buried at a depth of about 2.45 meters (8.04 feet) below the present ground surface (Figure 27). Apart from being buried, KIN-80 is important as one of the oldest cultural deposits so far identified in the San Joaquin Valley, and the presence of freshwater shell confirms that a lake was present in the basin during the early Holocene. The age of this deposit closely matches the buried cultural stratum identified at KER-116 along the shores of Buena Vista Lake, where the next oldest cultural date (8379 cal BP; LJ-1356) from the valley was obtained on freshwater mussel shell (Fredrickson and Grossman 1977).

An episode of early Holocene deposition is recognized within Tulare Lake Basin, where lacustrine sediments dating to 10,160 cal BP (OS-72700) are unconformably overlain by desiccated lake clay showing soil development, dating to about 8355 cal BP (OS-72699; Figure 27). A buried soil of similar age was also identified on the nearby Tulare River fan, between the towns of Corcoran and Tipton. In this location, two vertically stratified buried soils are overlain by surface soils of the Colpien series (Figure 27). The lower 3ABkb horizon yielded a date of 8379 cal BP (Beta-255483), matching the date from Tulare Basin, while the overlying 2ABkb horizon produced a date of about 7850 cal BP (OS-73065). The latter period of soil development is, in turn, matched along the Fresno River near the base of the Sierra foothills (Figure 27), where a nearly identical date of about 7845 cal BP (OS-70242) was derived from the deepest of five buried soils (5Ab). A date from the overlying soil (4Ab) at that location indicates that the early Holocene surface was buried before about 6920 cal BP (OS71155). These examples demonstrate that two widespread, early Holocene buried soils are present on the eastern side of the San Joaquin Valley dating to about 8500 and 7800 cal BP, respectively, separated by an intervening period of deposition.

Evidence for early Holocene land stability and subsequent deposition can also be found within many alluvial landforms on the western side of the valley. At Tumey Gulch, for example, deposition is constrained between 13,050 cal BP (OS-72832) and 9815 cal BP (OS-72830) based on dates from a deeply buried soil (5ABtkb) and an overlying moderately developed buried soil (2Abkb); the later buried soil also indicates that deposition in this locality occurred sometime again after 9815 cal BP (Figure 27). A similar period of stability and deposition is also represented along Little Panoche Creek, where a well developed buried soil (4ABtb) was dated to about 9440 cal BP (OS-71213; Figure 27).

Further down Little Panoche Creek, a weakly developed soil near the base of the alluvial terrace dates to 8235 cal BP (OS-71197), while the overlying buried soil (2Ab) dates to about 6100 cal BP (OS-71158), indicating that deposition resumed and ceased within that time span (Figure 27). This matches a depositional episode along the Fresno River on the eastern side of the valley. Another example of substantial early Holocene deposition is found along Panoche Creek, where a date of about 7540 cal BP (OS-70249) was obtained from a burn layer exposed near the base of an alluvial terrace, now more than ten meters (33 feet) below the surface (Figure 27). 529
San Joaquin River
Avenue 7
9 Road
Mendota
Firebaugh
Fresno County
Fresno CountyMadera County
Madera County
Avenue 7 1/2
WaterArtificial Cut and FillHistorical and Modern
Latest HoloceneLatest Holocene VolcanicLate Holocene
Holocene Volcanic (undivided)Middle HoloceneEarly Holocene Early Holocene VolcanicLatest PleistoceneLate Pleistocene Older PleistocenePre-QuaternaryHighway 0 1 2 Miles
For greater resolution and visual clarity, please refer to GIS database.

Figure 25. Early Holocene Fan and Basin Deposits in the Eastern San Joaquin Valley.

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California Department of Transportation, District 6/9
Geoarchaeological Study
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,
't~ • f..
.. '-i1:
~<
530
Latest Pleistocene
Crescent
0 1
2 3
4 5
6 7
8 9
10 11
cal Years BP (200 yr intervals)
Early Holocene Middle Holocene
Late
Holocene
Latest
Holocene
Number of 14C Dates
15,000
14,000
13,000
12,00011,000
10,000
90008000
7000
60005000
4000
3000
2000
1000
0 Natural Buried Soils
Cultural Buried Soils
Figure 26. Age and Frequency of Radiocarbon Dates from Buried Soils Associated with Natural and Cultural Contexts in District 6/9.

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Vernalis series
surface soil
Tulare series surface soil
A
C
Ck
2Ab
2Cox
3Cg
A
C
Ck
2Ab
2Cox
3Cg
Drainage Canal Intersecting Former Shoreline of
Tulare Lake at KIN-80 to North, Kings County
2Ab - 8358 cal BP
(OS-72699)
3Cg - 10,161 cal BP
(OS-72700)
Detail of 10th Street Canal
Deposits, Kings County
3Ab - 8971 cal BP
(OS-70224)
freshwater shell
(cultural)
Early Holocene Cultural Deposits
at KIN-80, 2.4-2.5 Meters Depth
Buried Soils in Northwest Bank of
Tulare River, Tulare County
2ABkb - 8379 cal BP
(Beta-255483)
3ABkb - 7848 cal BP
(OS-73065)
2ABkb - 9816 cal BP
(OS-72830)
Burn Layer in South Bank of Panoche
Creek Terrace, Fresno County
Burn Layer 10.4-10.5 Meters Below
Panoche Creek Terrace
North Bank of Tumey Gulch in Western
Fresno County to Southwest
2ABkb Horizon at 80-100 cm
in Tumey Gulch, Fresno County
7541 cal BP
(OS-70249)
West Bank of Upper Little Panoche Creek,
Western Fresno County
A
C
2Ab
2Bwb
3Ab
3Btkb
3Cu
4ABtb - 9440 cal BP
(OS-71213)
A
C
2Ab
2Bwb
3Ab
3Btkb
3Cu
4ABtb - 9440 cal BP
(OS-71213)
Vernalis series
surface soil
Vernalis series
surface soil
Sample Locations in South Bank of Lower Little Panoche Creek, Western Fresno County
2Ab - 6104 cal BP
(OS-71158)

1.4-1.6 meter 1.4-1.6 meters bs
Calflax series
Millham series surface soil Millham series surface soil surface soil Colpien series surface soil
Tulare Lake Basin
Wasco series
surface soil
(5?)Ab - 8236 cal BP
(OS-71197)

4.9-5.1 meter 4.9-5.1 meters bs
Buried Soil (2Ab) and Lacustrine Deposits (3Cg)
in West Bank of 10th Street Canal, Kings County
Figure 27. Selected Views of Radiocarbon-Dated Early Holocene Deposits in the San Joaquin Valley.

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These examples show that land stability and soil formation was the dominate process on both side of the San Joaquin Valley during the early Holocene, with widespread buried soils dating about 9800 to 9400 cal BP, 8500 to 8200 cal BP, and 7800 to 7500 cal BP. Substantial depositional episodes occurred between these stable periods burying many early Holocene land surfaces. Sediment deposition occurred mainly around the margins of large basins and on the lower portions of alluvial fans and floodplains on both sides of the valley. Because the region was clearly occupied by people during this time, it is also likely that early Holocene-age archaeological sites in these settings were buried as well.

Middle Holocene (7000 to 4000 cal BP)
The climatic conditions of the middle Holocene have long been characterized as distinctly warmer and drier than today, based on studies from the Great Basin and Desert Southwest (Antevs 1955; Baumhoff and Heizer 1965). While some Sierra records support this view (e.g., dendrochronologic, paleohydrologic), pollen and macrofossil evidence indicates that conditions were cooler and wetter between about 7000 and 4000 cal BP (Anderson 1990; Anderson and Smith 1994; Davis et al. 1985; Davis and Moratto 1988; Davis et al. 1976; Koehler and Anderson 1994; Wood 1975; Woolfenden 1996). The nature and extent of landscape changes during this interval are further complicated as middle Holocene-age landforms only rarely occur at the surface.

Despite a lack of consensus, the combined evidence suggests environmental conditions of the middle Holocene were variable and complex. The presence of submerged tree stumps beneath the waters of Lake Tahoe, dated between about 5,700 and 5,400 cal BP (Lindström 1990), however, provides proof of aridity and the extreme climatic variability of the middle Holocene.

As noted in a previous chapter, the middle Holocene represents a conspicuous “gap” in the stratigraphic record of Central California as no deposits of this age have been identified by previous geological studies in this region, either buried or at the surface (see Table 3, e.g., Hall 1984; Harden and Marchand 1980; Marchand and Allwardt 1981). However, middle Holocene radiocarbon dates from buried stratigraphic contexts are relatively common in this region (see Table 8). Included among these are 25 dates from buried soils identified in floodplains and meadows of the Sierra Nevada (Goldberg and Skinner 1990; Koehler and Anderson 1994; Peak and Neuenschwander 1991); alluvial fans and low-angle hillslopes in the Sierra foothills (Meyer and Dalldorf 2004; Meyer et al. 2008); alluvial fans, floodplains, and basins in the San Joaquin Valley (Atwater et al. 1990; Culleton et al. 2001; Gardner et al. 2005; Negrini et al. 2006; with most from this study); and a fault-related sag pond near the Tejon Pass (Madden and Dolan 2008). Most of these dates (n=17, 68%) range between about 6400 and 4500 cal BP (see Figure 26), with a mean age of about 5455 cal BP overall (see Table 9).

A period of widespread deposition at the beginning of the middle Holocene is evinced by the burial of early Holocene surfaces at several locations within the Study Area. A buried soil (2Ab) exposed below the surface of an alluvial terrace along Little Panoche Creek yielded a date of about 6100 cal BP (OS-71158). A slightly older date of 6920 cal BP (OS-71155) was obtained from a buried soil (4Ab) exposed in an alluvial terrace along the Fresno River in eastern Fresno County (Figure 28). These two buried soils were found above early Holocene surfaces dated to 8235 and 7845 cal BP, respectively, suggesting that a period of deposition occurred in this region after about 7800 years ago, but before 6900 years ago. Along the Fresno River, a second middle Holocene buried soil (3Ab), dated about 5590 cal BP (OS-71154), was also identified, matching the age of a buried land surface near Firebaugh in the San Joaquin Valley proper (Figure 28). In this locality, a buried soil (4Ab) exposed near water level in an alluvial terrace on the eastern side of the San Joaquin River produced a date of about 5285 cal BP (OS-70228). Likewise, a nearly identical date of 5235 cal BP (Beta-255479) was obtained from a truncated buried soil (3Btb) exposed along Berenda Creek near Chowchilla (Figure 28), also in the San Joaquin Valley. These localities on the eastern side of the valley suggest that a period of widespread middle Holocene land stability prevailed, following an initial period of deposition.

In western Fresno County, the channels of Panoche and Los Gatos creeks have become deeply incised, creating a series of extensive natural exposures that provide evidence for the rate and timing of middle Holocene deposition on the western side of the Valley (see Figure 28). Dates obtained from a large cut-bank near the confluence of Silver Creek with Panoche Creek indicate that more than five meters (16 feet) of sediment were 533
Overview of Deposits and Location of Black Mat Exposed
in the North Bank of Los Gatos Creek, Fresno County
Pachappa series (buried)
Greenfield series (buried)
3Btb
Excelsior series
surface soil
Overview of Deposits and Location of Buried Tree Root in the North Bank of Los Gatos Creek, Fresno County
Overview of Deposits Exposed in the East Bank
of Berenda Creek, Madera County
Detail of Sample Locations
in East Bank of Berenda
Creek, Madera County
2Ab cal BP
(OS-72823)
3Btb - 5233 cal BP
(Beta-255479)
Location of Buried Tree Stump in the North Bank
of Los Gatos Creek, Fresno County
Remains of Buried Tree
Stump, North Bank of Los
Gatos Creek, Fresno County
4651 cal BP
(OS-70215)
Remains of Buried Tree Root,
Near Base of North Bank, Los
Gatos Creek, Fresno County
4367 cal BP
(OS-71156)
Gray Pine Cone Near Base of
Excelsior (T2) Terrace, South
Bank of Los Gatos Creek,
Fresno County
4331 cal BP
(OS-71157)
2Ab
4552 cal BP (OS-70215) on Black Mat at
13 meters

10.5 Meters Below Surface
~13 meters

1.5 meters
Excelsior/Cerini series
surface soils
Posochanet series
surface soil
Figure 28. Selected Views of Radiocarbon-Dated Middle Holocene Deposits in the San Joaquin Valley.

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deposited there between about 4870 cal BP (OS-71160) and 4685 cal BP (OS-70250) over an interval of less than 200 years. A similar pattern was found at Los Gatos Creek where more than seven meters (23 feet) of sediment were deposited between about 4650 cal BP (OS-70215) and 4330 cal BP (OS-71157) over an interval of no more than 320 years. The date of 4650 cal BP and another of 4365 cal BP (OS-71156) were obtained on wood from buried tree stumps rooted in formerly stable land surfaces (see Figure 28). Notably, the latter date is almost the same as 4330 cal BP (OS-71157) from a gray pine cone embedded in unweathered alluvium along the same creek (see Figure 28).

In addition, a thin mat of carbonized organic materials, buried more than ten meters (33 feet) below the surface of the Los Gatos Creek terrace (see Figure 28), appears to mark a very brief episode of plant growth at around 4550 cal BP (OS-70221). Further, one of the few middle Holocene-age archaeological sites identified in the study area was found along this same stretch of Los Gatos Creek (Atwater et al. 1990), buried at a depth of about seven meters (23 feet) below surface. It dates to about 5270 cal BP (C-1424).

Radiocarbon dates from buried land-surfaces along both Panoche and Los Gatos creeks, clearly demonstrate that extensive deposition occurred on the western side of the San Joaquin Valley between about 4800 and 4300 cal BP, delivering as much as five to ten meters (16 to 33 feet) of sediment in a period of just 200 to 300 years. As the depositional landform map developed for this study shows (see Figure 17), there are very few areas in the San Joaquin Valley where middle Holocene-age landforms are represented at the present surface.

However, a moderate-size area is found in the lower drainage of Little Panoche Creek (western Fresno County), where soils of the Chateau, Deldota, and Paver series are mapped at the surface. A date of about 4755 cal BP (Beta-255481) from the Bk horizon of the Deldota soil confirms the middle Holocene age of these soils. Other middle Holocene-age surfaces occur along the lower drainages of the Kaweah and Tule rivers on the eastern side of the valley (Tulare County), mapped as having surface soils of the Akers and Tagus series (Figure 29). The age of these soil series was inferred based on geomorphic position and the type and degree of soil development compared to neighboring soil units.

In each of these areas, middle Holocene deposits form the central (medial) portions of alluvial fans generally occupy an intermediate position between older and younger deposits (i.e., early Holocene or more, late Holocene or less). Smaller and more isolated middle Holocene surfaces also occur along the eastern side of the valley in Fresno and Madera counties (mainly Pachappa Series at surface), where they form small alluvial fans, and stream terraces, and appear to fill small abandoned stream channels.

Overall, middle Holocene surface landforms are the least represented and the most spatially restricted of all those exposed at the surface of the San Joaquin Valley. In combination with evidence for extensive deposition toward the end of this period, the narrow distribution of these surfaces explains why no specific middle Holocene deposits or correlative stratigraphic units have previously been identified in the region (see Table 3; Hall 1984; Harden and Marchand 1980; and Marchand and Allwardt 1981).

These examples clearly show that the nature, pace, and magnitude of middle Holocene landscape changes varied greatly from one area to another. The assembled radiocarbon and stratigraphic data suggest that this interval is bracketed by at least two major depositional pulses: the earliest was between about 7000 and 6800 cal BP, and the latest centered between about 4500 and 4300 cal BP. During the intervening 2,200-year period (~6800 to 4500 cal BP) most or all landforms were essentially stable and passively undergoing soil development.

This paints an emerging picture of the middle Holocene as a time of environmental transition in which climates grew more variable and shifted more abruptly than during the early Holocene. While the overall trends may have been toward warmer and drier conditions and landscape stability, the substantial depositional episodes that bracket this interval require greatly increased and/or sustained levels of precipitation for sediment transport to occur at such a large scale. It also appears that most middle Holocene landforms have been buried. These surfaces tend to occur in relatively low landscape positions (e.g., incised arroyos and channels, inset terraces, distal fans, and basin rims) and have since became depositional loci for younger sediments (Meyer and Dalldorf 2004; Meyer et al. 2008; Meyer and Rosenthal 2008). Because of this, we expect that many middle Holocene archaeological sites are also buried in the same geomorphic settings where these buried soils tend to be preserved. The upper stratum at site KIN-80 is one such example, dated to about 4955 cal BP (Beta-167852). It lies buried along the 535
Little Panoche Creek
Merced County
Fresno Coun
Brito ty
Dos Palos
Oro Loma
Oxalis
Laguna Seca Creek
Avenue 21
Road 600
Avenue 20 1/2
Howard
Fresno River
South Fork Fresno River
Biola
Madera
Herndon
Berenda
Pinedale
Chowchilla
Dry Creek
San Joaquin River
Berenda Creek
Berenda Slough
Little Dry Cree k
Ash Slough
Eastside Bypass
Root Creek
Mud Spring Cree k
Daulton Creek
Schmidt Creek
Madera County
Fresno County
Avenue 14
Avenue 7
0 2 4 Miles
0 2 4 Miles
Calders
Corner
Fruitvale
Gosford
Kern
City
Water
Artificial Cut and Fill
Historical and Modern
Latest Holocene
Latest Holocene Volcanic
Late Holocene
Holocene Volcanic (undivided)
Middle Holocene
Early Holocene
Early Holocene Volcanic
Latest Pleistocene
Late Pleistocene
Older Pleistocene
Pre-Quaternary
Highway
Figure 29. Middle Holocene Fan and Basin Deposits in the Western (top) and Eastern (bottom) San Joaquin Valley.

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western rim of Tulare Lake Basin beneath more than 1.5 meters (4.9 feet) of alluvium (Gardner 2003; Gardner et al. 2005). Together, the Los Gatos Creek site and KIN-80 are the only middle Holocene sites so far identified in the lower San Joaquin Valley.

Late Holocene (4000 to 2000 cal BP)
Unlike the two previous intervals of the Holocene, climate during the late Holocene was generally cooler and wetter, thus heralding a transition to the mesic conditions that prevail today (West 2000). This overall trend is widely reflected in pollen records from high and low elevations on both sides of the Sierra Nevada (Anderson 1990; Anderson and Smith 1994; Benson et al. 2002; Davis 1999a, 1999b; Davis and Moratto 1988; Davis et al. 1985; Edlund 1991; Goman and Wells 2000; Jones and Waugh 1997; Koehler and Anderson 1994; MalamudRoam et al. 2006; Smith 1979; Smith and Anderson 1992; Stine 1990; Wells and Goman 1995; West 1993, 2005; Wood 1975), in tree-ring and plant macrofossil records of the southern Sierra Nevada (Anderson 1990, 1994; Anderson and Smith 1997; Scuderi 1987), and Bristlecone Pine records from the White Mountains (Berkelhammer and Stott 2008; Ferguson 1970; LaMarche 1974).

Evidence of increased precipitation and runoff during this interval is recorded by high lake stands throughout the otherwise arid Great Basin and Mojave Desert regions, such as Mono and Owens lakes (Benson et al. 2002; Stine 1990), Searles Lake (Smith 1979), Silver Lake (Enzel et al. 1989, 1992), Walker Lake (Benson et al. 2002), Lower Pahranagat Lake and Diamond Pond (Wigand and Rhode 2002), as well as other lakes throughout the American West (Harrison and Metcalfe 1985). Together these records indicate that significant and widespread flooding occurred in the region between about 4000 and 3600 cal BP. Sediments within the Tulare Lake Basin also record a high stand during the first part of the late Holocene, but a low stand occurred around 2200 cal BP, marking a period of drought toward the end of this interval (Davis 1999a; Negrini et al. 2006).

These changes are also reflected in the depositional history of many alluvial fans and floodplains in central California, where multiple episodes of late Holocene deposition are recognized (Rosenthal and Meyer 2004a, 2004b). Roughly synchronous periods of fan and floodplain deposition are also documented on the western slope of the Sierra (Meyer and Dalldorf 2004) and in the Sacramento Valley (Meyer and Rosenthal 2008; White 2003b). Buried soils dating to the late Holocene are most commonly centered at about 2900 cal BP based on 25 radiocarbon dates from locations throughout the region (see Table 9). These records and others from around central California show that landform changes accelerated during the late Holocene as cooler/wetter conditions initially increased the amount of available sediment through erosion, and elevated the capacity of rivers and streams to carry these sediments downstream. The net result was widespread sediment deposition and the formation of new alluvial landforms. The continuation of cooler/wetter conditions eventually led to greater plant growth and vegetative cover which allowed landforms to become more stable, thus slowing the rate of landscape changes well before 2000 cal BP.

Based on the soil-age assignments of this study, late Holocene surface deposits are present on the east and west sides of the San Joaquin Valley, mainly in Fresno County, and at the valley’s southern end in Kern County (see Figure 17). The largest and most continuous surface deposits occur along the western side of the valley where they form distal alluvial fans and basin deposits near the valley’s main trough (Figure 30). Soils at the surface of these landforms are mapped as Calflax, Ciervo, Lillis, Tranquility, and Wekoda and consist mainly of clay, with Calflax clay loam being the only exception. The maximum age of the Calflax series is constrained by a date of about 4685 cal BP (OS-70250) from a buried soil (2Ab) immediately beneath the Calflax soil, and a second date of about 4870 cal BP (OS-71160) from the 2Cu-horizon in which the buried soil had formed, both from an alluvial terrace near the confluence of Panoche and Silver creeks in Fresno County (Figure 31). Other soil-ages were inferred based on their geomorphic position and the type and degree of soil development compared to neighboring soils radiocarbon-dated to the latest Holocene (i.e., Cerini, Excelsior, Panoche, and Posochanet series). Because these fan and basin deposits consist of sediments derived from western hill slopes, where the modern climate is normally arid, the large size and extent of these landforms suggest they formed at a time when rainfall and runoff levels were much higher than today, and possibly higher than the early and middle Holocene. 537
Helm
Calwa
Biola
Lanare
Kerman
Fresno
Easton
Camden
Burrel
Rolinda
Mendota
Riverdale
San Joaquin
Tranquillity
San Joaquin River
Cantua Creek
North Fork Kings River
Faull Slough Kings R vi er
California Aqueduct
Fresno Slough
Kings County
Fresno County
Madera County
Fresno County
WaterArtificial Cut and FillHistorical and Modern
Latest HoloceneLatest Holocene VolcanicLate Holocene
Holocene Volcanic (undivided)Middle HoloceneEarly Holocene Early Holocene VolcanicLatest PleistoceneLate Pleistocene Older PleistocenePre-QuaternaryHighway 0 1 2 Miles
For greater resolution and visual clarity, please refer to GIS database.

Figure 30. Late Holocene Fan and Basin Deposits in the Western San Joaquin Valley.

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Sample Location (above and below) in
Fan/Terrace North of Fresno River,
Fresno County
2Ab - 3759 cal BP
(OS-70216) Visalia series surface soil
Sample Location in South Bank of Wahtoke Creek at FRE-61, Fresno County (above) Foster series surface soil
2Ab - 2246 cal BP
(OS-72794)
2Ab - 2246 cal BP
(OS-72794)
Hesperia series surface
soil
Hesperia series surface
soil
Hesperia series surface soil
Sample Location in Fan/Terrace North of Kern River, Kern County 2Ab - 4089 cal BP
(OS-70244)
3Ab - 5592 cal BP
(OS-71154)
4Ab - 6918 cal BP
(OS-71155)
5Ab - 7846 cal BP
(OS-70242)
2Ab - 4089 cal BP
(OS-70244)
3Ab - 5592 cal BP
(OS-71154)
4Ab - 6918 cal BP
(OS-71155)
5Ab - 7846 cal BP
(OS-70242)
Visalia series surface soil
Sample Location at ~6.5 Meters Below
South Bank of Panoche Creek Terrace,
San Benito County, Near Fresno County
Line (above)
Panoche series surface soil
5Ab -
2859 cal BP
(OS-71202)
Foster series surface soil
Sample Location Near Firebaugh in East Bank of San Joaquin River, Fresno County 2Ab - 2014 cal BP
(OS-70227)
3Ab - 3385 cal BP
(OS-71201)
4Ab - 5286 cal BP
(OS-70228)
2Ab - 2014 cal BP
(OS-70227)
3Ab - 3385 cal BP
(OS-71201)
4Ab - 5286 cal BP
(OS-70228)
Foster series surface soil
Deposits Exposed in South/East Bank of Cottonwood Creek, Madera County 2Ab -
3929 cal BP
(OS-71316)
Atwater series
(buried)
2Ab -
(buried)
Hanford series
surface soil
Hanford series
surface soil A
Cu
2Ab
2Btb
3Btb
State Route 180
San Joaquin River
Figure 31. Selected Views of Radiocarbon-Dated Late Holocene Deposits in the San Joaquin Valley.

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Far Western 82 Transportation Enhancement Activities Program California Department of Transportation, District 6/9
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Along the eastern side of the valley trough, late Holocene deposits occur at the surface in an elongated area, where they occupy basin and floodplain positions (see Figure 30). Here the surface soils are mapped as the Altaslough, Merced, and Temple Series which are composed of fine-grained alluvium (mainly clay or clay loam).

The minimum age of the Merced series is constrained by a date of about 970 cal BP (Beta-255482) from the Ahorizon of this soil where it was buried (i.e., 2Ab) by younger deposits within Fresno Slough (see Figure 31). The ages of the Altaslough and Temple series were inferred based on their geomorphic position and degree of soil development, which is similar to the Merced series, and on comparisons with neighboring soils radiocarbon-dated to the latest Holocene (e.g., Chino and Grangeville series). While previous researchers have associated the Merced and Temple soils with both latest Pleistocene and Holocene landforms (see Table 6), we conclude that they are most likely late Holocene in age.

Because late Holocene deposits on the eastern side of the valley consist of sediments derived mainly from the Sierra Nevada, the size of these landforms again suggests they were deposited under conditions of greater rainfall and runoff. The extent and position of these landforms further suggest they were formed mainly by outwash from the Kings River fan, and were deposited within a basin created in part by blockage (damming) of the normal drainage outlet by sediments deposited near the town of Mendota (see Figure 30).

Late Holocene deposits also occur at the surface along the San Joaquin River west of Fresno, where they form small and segmented alluvial fans, floodplains, and stream terraces with soils of the Hesperia series. The age of the Hesperia Series is based on 15 radiocarbon dates obtained almost exclusively from cultural surface deposits at sites outside the San Joaquin Valley. These dates range from a maximum of about 3290 cal BP (Beta-158024) at INY-5275/H, to a minimum of only 130 cal BP (Beta-112083) at INY-3769 (Appendix B). Two dates below Hesperia soils, however, are from natural buried contexts, including one of about 5265 cal BP (USGS-0607) from Antelope Valley (Kern County), and one of about 2245 cal BP (OS-72794) from a buried soil (2AB) exposed in a terrace along the Kern River near Bakersfield (see Figure 31). Although the maximum surface date and minimum buried date from this soil series overlap by about 1,000 years, the best fit of all dates indicate that landforms with Hesperia soils date to the late Holocene in most areas, but may be latest Holocene in age (<2245 cal BP) in some regions (i.e., Kern River terrace). Like other soils, the Hesperia series has also been associated with both latest Pleistocene and Holocene landforms by previous studies (see Table 6).

Late Holocene deposits are found in portions of the Kern and Buena Vista Lake basins at the southern end of the San Joaquin Valley, where they form smaller and less continuous alluvial fan, floodplain, and basin deposits.

These landforms have soils of the Calflax, Hesperia, Tupman, and Zalvidea series mapped at their surfaces. The age of the Tupman and Zalvidea soils was inferred based on their relative geomorphic position and the type and degree of soil development compared to the Calflax and Hesperia series, and on neighboring soil bodies (i.e., Cerini, Excelsior, Kimberlina, and Posochanet series) that date to the latest Holocene. The distribution of these landforms in or near the margins of Kern and Buena Vista basins suggests they were deposited when water levels were higher within these lakes, which raised the hydrologic baseline for sediment deposition.

This evidence reinforces the view that a significant increase in rainfall initially occurred during the late Holocene that altered existing hydrologic systems, destabilized landscapes, and prompted widespread sediment deposition between about 4000 and 3600 cal BP. As conditions remained cooler and wetter, plant growth and greater vegetative cover allowed old and new landforms to stabilize and soil formation to prevail by about 2900 cal BP. It also appears that late Holocene deposition was more pronounced and/or extensive in the western and southern parts of the valley, where there is generally less rainfall and vegetation cover. While late Holocene landforms are also recognized along the east side of the valley and within the valley trough, the distribution of these landforms appears to be restricted to the alluvial fans of the Kings and San Joaquin rivers, and a corresponding portion of the lower valley trough. This suggests that deposition was not as pronounced or extensive at the base of the Sierra Nevada, perhaps due to the greater rainfall and vegetation cover normally associated with this region. At the same time, the large number of buried soils less than 2000 cal BP in age, provides strong evidence that a substantial part of the late Holocene landscape was buried during the latest Holocene (see Table 6; see Figure 26). The number of dated late Holocene-age cultural contexts in the region reflects this, with about 72.5 percent from surface contexts, and just over one-quarter (~27.5%) from buried contexts (see Figure 24).
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Latest Holocene (2000 to 150 cal BP)
“More variable” best describes the contrast between the late and the latest Holocene climate. While it remained relatively cool and wet overall, there were also abrupt temperature swings and extreme precipitation shifts that were as dramatic as any in the Holocene. These changes include one or more episodes of increased rainfall between about 2000 and 1670 cal BP (Davis 1999a; Ingram et al. 1996; Negrini et al. 2006), two intense droughts within the Medieval Climatic Anomaly between about 1100 and 650 cal BP (Jones et al. 1999; Stine 1994), the rapid onset of the Little Ice Age (i.e., Matthes glacial) and return to cooler and wetter conditions after about 650 cal BP, and another severe drought between 482 and 370 cal BP (Hughes and Brown 1992; Meko et al. 2001). From these records, as many as four major droughts and precipitation cycles are apparent between about 2200 and 600 cal BP. Because of the rapid, repeated, and widespread nature of these changes, the present landscape still bears the lasting signature of latest Holocene climate variability.

Not surprisingly, evidence of large-scale flooding and deposition during the latest Holocene is found throughout much of central California. For example, the age of surface alluvial and colluvial deposits in the Sierra Nevada foothills is constrained between about 1400 and 150 cal BP by nearly one-dozen radiocarbon dates (see upper Keystone deposits of Meyer and Dalldorf 2004). Radiocarbon-dated sediments along the South Fork American River indicate that large floods occurred during the latest Holocene (1125-650 cal BP) and buried many older land surfaces and associated archaeological sites (Bureau of Reclamation 2002:34). In the northern Diablo Ranges of Contra Costa County, alluvial and colluvial surface deposits have been dated between about 660 and 250 cal BP (see Brentwood unit of Meyer and Rosenthal 1997:34-35).

Within the past 2,000 years, a sizable body of alluvium was also deposited across the central part of the lower San Joaquin Valley and in the narrow valleys along most rivers and streams draining the Coast Ranges and Sierra Nevada (Rosenthal and Meyer 2004b). These deposits form a nearly continuous belt of alluvium on either side of the San Joaquin River channel, broad basins and floodplains in the lower San Joaquin Valley, and marshes in the Delta region. Dozens of radiocarbon dates from the associated surface deposits indicate that these landforms are generally less than 1000 cal BP in age (Meyer and Rosenthal 2008). The soil-age based mapping used by this study shows that the majority of the San Joaquin Valley is covered by latest Holocene-age surface deposits (see Figure 17). These form an almost continuous series of alluvial fans, floodplains, and basins along both sides of the valley, as well as a uniform ribbon through the valley’s central trough. The various soil series mapped at the surface of these landforms are far too numerous to mention individually but are listed in Appendix C. Nearly 700 latest Holocene-age radiocarbon dates are available from the Study Area, including several new dates obtained from soils of the Foster, Hanford, Kimberlina, and Wasco series (discussed below). Included among these are 49 dates from buried soils, ranging in age from about 1985 to 130 cal BP, with a mean age of about 1075 cal BP (see Table 6).

On the east side of the valley, along the San Joaquin River near Firebaugh, the age of the Foster-series is constrained by a date of about 2015 cal BP (OS-70227) from a buried soil (2Ab; Figure 32). The first buried soil (2Ab) below the Hanford series along Cottonwood Creek, also on the valley’s eastern side, gave a limiting age of about 1130 cal BP (OS-71200), while a more deeply buried soil (3Ab) near the base of the same alluvial terrace (T2) yielded a maximum age of about 1880 cal BP (OS-71200). On the highest terrace (T3), a date of about 3635 cal BP was obtained from the eroded surface of an exposure of Atwater series soils capped by Hanford soils (see Figure 31). Thus, along Cottonwood Creek, it appears that Hanford-series soils are associated with more than one depositional episode, and possibly three. Along the San Joaquin River in Fresno County, a buried soil (2Ab) below Wunjey-series soils produced a much younger date of about 130 cal BP (OS-72582). This is interpreted as a minimum age for the Wunjey, as this particular exposure appears to be overlain by historic-era alluvium (Figure 32).

On the valley’s western side, a maximum age of about 1605 cal BP (OS-67051) was obtained for the Kimberlina series from a cultural hearth feature exposed about 4.4 meters (14.4 feet) below surface in the side wall of Arroyo Hondo Creek (FRE-257) located near Interstate 5 in Fresno County (Figure 32). The minimum age of the Kimberlina series is constrained by a slightly younger date of about 1265 cal BP (Beta-188993) from buried cultural deposits at KER-3085 in the Elk Hills (Culleton 2006, Culleton et al. 2005). The latest Holocene-age 541
Deeply Buried Hearth Feature in North Bank of Arroyo Hondo Creek (FRE-257), 4.3 to 4.5 Meters Below Surface, Fresno County Sample Location in South Bank of San Joaquin River, Fresno County (red and white tape is 2 meters long)
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Figure 32. Selected Views of Radiocarbon-Dated Latest Holocene and Historic to Modern Deposits in the San Joaquin Valley.

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alluvial fans on the valley’s western side in Fresno County are not as extensive as their late Holocene predecessors, suggesting that rainfall and runoff were not as high and/or sustained in the latest Holocene as in the late Holocene, again pointing to more variable conditions overall (see Figure 17).

One of the single largest alluvial deposits formed in the valley during this time was the lower portion of the Kings River fan (Figure 33), which probably began blocking the northern Tulare Lake outlet between about 2000 and 600 cal BP. This suggests that the highest stands of Tulare Lake could only have occurred once the fan was deposited and the “dam” fully formed in the latest Holocene, instead of the latest Pleistocene as argued by Atwater et al. (1986). As noted above, and in the previous chapter, the lake does not appear to have reached its highest stand until about 175 cal BP (OS-73445) based on evidence from the Lethent fan. It is also possible that the northern side of the Kern and Buena basins was blocked by deposition on the lower Kern River fan in the latest Holocene (Figure 33) which could have raised lake levels and/or increased the lake’s overall extent.

Given the widespread nature of these deposits, the latest Holocene emerges as one of the most influential periods of landscape change since humans first arrived in the San Joaquin Valley more than 11,500 years ago.

Characterized by highly variable climatic conditions that alternated rapidly and repeatedly between intensely dry and extremely wet, these fluctuations destabilized many upland portions of the landscape and overloaded many rivers and streams with far more sediment than they could adequately transport. This caused widespread deposition on the San Joaquin Valley floor, and in other valleys, at a scale as aerially extensive as any depositional interval. Many hydrologic systems were also altered during this time, as once active channels were abandoned in favor of new ones, and major drainage basins (i.e., Tulare Lake) were impounded and/or enlarged.

Historical to Modern (150 to 0 cal BP)
The last major phase of landscape development occurred during the historical and modern eras in response to agriculture, irrigation, land reclamation, livestock grazing, timber logging, dredging, mining, quarrying, and the replacement of some native plants by nonnative species (Figure 34). Most of the San Joaquin Valley floor has been cultivated for crops or reclaimed for agricultural purposes, such as the area once occupied by Tulare Lake (Figure 34). Evidence of dredging or quarrying is found within river bottoms on the valley floor (e.g., San Joaquin River, Kaweah River), extensive deposits of mine-tailing also occur along many of the major stream and river channels. During the height of the gold rush in the late 1800s, hydraulic mining in the northern Sierra Nevada generated nearly one billion cubic meters of sediment that were released into channels draining the western slope (Gilbert 1917; Figure 11). Not surprisingly, this caused extensive flooding, channel migration, and widespread sediment deposition throughout the lower portions of the Sacramento and San Joaquin Valley (Thompson 1961: Figure 11).

During the 1880s, protective vegetation cover was greatly reduced by intense drought and livestock grazing, which made the land susceptible to erosion (Burcham 1982:171). This erosive period caused deep gullies and channels (i.e., arroyos) to form in many locations across the American West (Bryan 1925; Schumm and Hadley 1957), including some alluvial fans in western Fresno County (Bull 1964a, 1964b) and meadows in the southern Sierra (Dull 1995, 1999). Together these human-made changes have caused widespread erosion of the uplands and rapid sediment deposition in the lowlands, and fundamentally altered the drainage system, and the transport, deposition, and storage of sediment within the valley (Mount 1995).

More than 50 historic-era radiocarbon dates were identified from the study area, including four obtained for this study (see Table 8). These dates range in age from about 145 to 20 cal BP, with a mean age of around 100 cal BP (AD 1850), which puts most near the height of the gold rush period. Based on our mapping of the valley floor, deposits assigned to the historical and modern group are largely restricted to the active channels of modern fans and floodplains along perennial streams and rivers, such as the lower Kern and San Joaquin rivers (Figure 35), the lower Kings River, and within former lake basins that contained water during recent times (i.e., Buena Vista, Kern, and Tulare lakes).

The historical to modern map group also includes areas that were artificially cut and/or filled as a result of mining, construction, or urban development, which includes earthen dams, landfills, dredging piles, some highway and railroad embankments, and backdirt from quarries. While there is considerable variation in the 543
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Figure 33. Latest Holocene Fan and Basin Deposits in the San Joaquin Valley.

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Fleet of Grain Harvesters on Glenn Ranch in Tulare Lake Area, Kings Co.? 1884 Flood at M St. South of Merced St. in Fresno California Stream Dredging at Johns Ditch, Kings County, 1890
Logging Crew and Giant Sequoia, Sierra Nevada,1890
Peoples Ditch Irrigation Dam, Kings County, 1895 Tractor Crew Plowing Field, Kings County, 1910 Removing Oaks, Laguna De Tache Land Grant, Kings Co.

Coalinga Oil Field, Fresno County,1896
Figure 34. Examples of Historic-era Land Use and Landscape Changes in the San Joaquin Valley and Adjoining Portions of District 6/9.

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Figure 35. Historical to Modern Deposits in the San Joaquin Valley.

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nature and texture of these deposits from location to location, they generally have undeveloped soil profiles, either because they have not been stable long enough, or because they were designed to resist weathering (e.g., dams, engineered fill). Modern artificial cut-and-fill deposits are still forming in the region.

GREAT BASIN AND MOJAVE DESERT
Geologic mapping in the Great Basin and Mojave Desert has focused on lithologic formations and structures of the prominent mountain ranges, with little attention to the “recent” valley fills (neotectonics and lake studies being prominent exceptions). The depositional units of the region lack cohesive naming conventions.

Mojave and Great Basin fan systems have often been mapped in detail (see studies in Enzel et al. 2003; geoarchaeological contexts by Young 2007; 2009) but these tend to rely on idiosyncratic spatio-stratigraphic labels (for example, Qf1-Qf7, oldest to youngest) through which only cursory correlations are possible. Solving the riddles of basin-to-basin fan, stream terrace, dune, and lake correlations is well beyond the scope of this study; however, general chronological and processual relationships can be extrapolated across the Study Area. The degree of soil development provides an organizing principal for initiating a regional study of buried site potential.

Late Pleistocene and Older (>15,000 cal BP)
Glacial cycles that pre-date the Tioga glaciation (i.e., Tahoe and older) and tectonic uplift (mountainward) and downdrop (basinward) have resulted in relic outwash fans forming a broad alluvial bajada west of the Owens River at the foot of the steep mountain-fronts (Figure 36). Older Pleistocene surfaces are typically boulder-strewn, steeply to gently sloping fans and coalesced fans extending from the mountain-front to the level terraces of the Owens River. As observed on the western side of the range, the alpine valleys of the eastern Sierra appear to have experienced significant scouring during older Pleistocene glacial cycles; Tahoe-age (or postTahoe interstadial) scouring and outwash must have been especially competent. As a result, the later Tioga cycles, with some local exceptions, had less material to work with and less energy to deliver significant amounts of material to the valley margins.

In desert regions, older Pleistocene fans show intensive pavement development and are often uplifted relative to younger inset fans and valley margin deposits. Even in the arid environments of the eastern basins, these surfaces retain well-developed soil profiles with moderate to strong, calcium-, clay-, or oxide-rich B horizons.

These landforms provide the foundation of the valley-bottom archaeological record.

Latest Pleistocene (15,000 to 11,500 cal BP)
Waning glaciation and high-amplitude fluctuations in larger lake basins were significant drivers of regional latest Pleistocene environmental change. As mentioned above, the Tioga glaciation may not have contributed large amounts of sediment to the eastern mountain front, and yet the hydrological cycling of wet-dry regimes resulted in active erosional and depositional cycles within eastside drainage systems. While smaller lakes in desert valleys, such as Searles and Eureka, returned but may not have reached earlier highstands, larger drainage systems experienced cyclical transgressions close to or reaching highstand levels. Lake Owens may have cycled between near-desiccation and sill-level overflow one or more times in several thousand years between glacial retreat and the close of the Pleistocene. Regional hydrological fluctuations, caused by atmospheric and oceanic perturbations as global systems responded to the termination of “ice-age” conditions (Benson et al. 1996; Benson et al. 1997; Phillips et al. 1996), produced concurrent erosion and deposition in valley-bottom environments.

Large-scale geomorphic change became focused in riverine systems and lacustrine basins (valley floors), where prominent terraces formed along major drainages, deltas prograded into receding lakes, and littoral features (beaches and strands) were cut and occasionally reinterred. The strong Pleistocene linkage between global oceanic dynamics and regional atmospheric conditions (jet stream position/moisture content) was coming undone, so that geomorphic and environmental systems of the Great Basin, including areas immediately east of the Sierra Nevada, began to respond to much more local conditions than to global drivers. This de-coupling marked the Pleistocene to Holocene transition; approaching that temporal boundary, the latest Pleistocene was a period of dramatic though attenuated fluctuations as new equilibriums were established. 547
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Figure 36. Older Pleistocene Fans Emanating from Glaciated and Unglaciated Drainages in the Owens Valley.

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In the valleys east of the Owens River, large lake stands became rare but the cyclical character of wet-dry episodes supported small lakes and broad wetlands in valley-bottom settings, many of which were maintained into the early Holocene (Quade et al. 1998; Wigand and Rhode 2002). Relatively rapid changes in regional hydrology within each wet-dry cycle produced active cycles of erosion and deposition. Well into the southern Great Basin and northern Mojave, fan surfaces eroded to leave truncated paleosols near or at the modern surface. In Fremont Valley, south of Ridgecrest, the bajada of Pine Tree Wash preserves an eroded paleosol buried by relatively recent alluvium. Following a period of regional landform stability (i.e., the period of soil development), portions of the bajada surface were stripped by erosion, removing (truncating) the upper A-horizons and leaving the more resistant Bt and Btk horizons. Deposition shifted to the distal fan resulting in broad fan progradation.

Radiocarbon dating on organics within the B horizon shows that the paleosol was well-developed at 15,030 cal BP (Beta-254726). This date provides a maximum for bajada erosion. A later paleosol dated at 10,760 cal BP (Beta-255187) on another area of the fan provides a minimum date for this phase of fan progradation at Pine Tree Wash and Fremont Valley.

Evidence of a similar landform sequence is found at Dove Springs Wash in Red Rocks State Park to the north. Although also buried by younger deposits, an eroded paleosol found throughout the Dove Springs and Red Rock area has been dated to 12,750 cal BP (Beta-18449; Whistler et al. 1990, 1994). The date comes from depositional organics (conifer fragments), and the paleosol formed soon after.

The Gunsight soil series formed on latest Pleistocene landforms in the northern Mojave (Figure 37). A series of radiocarbon dates on Anadonta shell in beach and bar features, now capped by the Gunsight soil, shows that these landforms were mostly deposited in the latest Pleistocene (Ore and Warren 1971; Wells et al. 1989). A period of highstands at Silver Lake corresponds with increased runoff and fan progradation throughout the Mojave River system at this time (Wells et al. 1989). Along the eastern front of the Sierra, latest Pleistocene deposits and corresponding soil series (e.g., Yermo and Timosea) are confined to upper fan segments and postglacial features near the mountain front and in steep-sided canyons. The latest Pleistocene-age Polenta series near Bishop formed on remnant alluvial terraces abandoned by the Owens River (Figure 37 and Figure 38). A surface date of 7,245 cal BP (Beta-53846; Pinter et al. 1994) provides a minimum age for underlying deposits that form large, segmented river terraces on the western side of the Owens River. Hydrological cycling characteristic of the latest Pleistocene flushed out large amounts of sediment from the Owens Valley, setting the stage for a complex terrace system along much of the river reach. During this period deposition was focused along lower reaches of the river and in the delta and littoral area of Owens Lake. This material has been worked more recently into an extensive aeolian-deposited berm and dune system north and east of Owens Lake.

Early Holocene (11,500 to 7000 cal BP)
Hydrologic cycling continued into the early Holocene, though the amplitude of high and low streamflows and the transgression and regression of regional lake levels began to lessen. In general, Great Basin landforms of the early Holocene were relatively stable. Prominent, well-developed soils dating to this period are relatively common, though most are buried beneath younger fan surfaces. The downcutting of previous intervals may have allowed fan surfaces to stabilize by confining fluctuating streamflows to relatively incised channels. Fans continued to prograde and may have engulfed axial valleys with sediment. In fact, early Holocene age landforms make up a significant percentage of mapped deposits in the eastern side of the Study Area. This, combined with the prevalent occurrence of early Holocene paleosols, suggests a generally stable period, with longer-term effective moisture (Bacon et al. 2003) and more equitable seasonality in the form of increased summer rainfall (Wigand and Rhode 2002).

Although the early Holocene is often considered the initial phase of general Holocene drying, precipitation and overall capacity of stream systems may have been relatively high compared to later periods.

Quade et al. (2003) have shown dramatic productivity in spring environments of the southern Great Basin. Black mats and lake deposits dated to this interval (10,640-9070 cal BP) at the Lava End Locality in Rose Valley, south of Owens Lake, provide evidence that the lower Owens system may have experienced mesic conditions. Based on dated lake deposits in Rose Valley, and evidence for a relatively deep lake in Searles Basin (Smith and Street549 Owens River
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Figure 37. Late Pleistocene Deposits in the Owens Valley (top) and Mojave Desert (bottom).

Aliso Viejo City CouncilDecember 3, 2025

Aliso Viejo City Council
December 3, 2025