Lake Forest City Council
March 17, 2026

Operational GHG emissions are calculated for area sources, mobile sources, water use, energy use, solid waste disposal, refrigerant use, stationary sources, and vegetation sequestration changes. Operational emissions are evaluated for the first year of proposed Project operation, i.e., calendar year 2027.

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4.3.1 Area Sources
Area sources are direct sources of GHG emissions, such as emissions from landscaping activities. The area source GHG emissions included in this analysis are landscaping-related fuel combustion sources, such as lawn mowers. These emissions are estimated in the CalEEMod output for the proposed Project in Appendix A-1.

4.3.2 Mobile Sources
The GHG emissions associated with on-road mobile sources are generated from customer and employee vehicles, delivery trucks (i.e., warehouse and tire center delivery trucks), and TRUs that are mounted on the trailers of some warehouse delivery trucks traveling to and from the Project site. The GHG emissions associated with on-road mobile sources include running and starting exhaust emissions. Running exhaust emissions are dependent on VMT.

Starting emissions are associated with the number of starts or time between vehicle uses and the assumptions used in determining these values are described below. Ramboll calculated mobile source emissions using trip rates based on analyses conducted by Kittelson109 and Project-specific information for warehouse and tire center delivery trucks.

The analysis includes the benefit of reductions from adopted regulatory programs that are accounted for within EMFAC2021 including Assembly Bill 1493 (“the Pavley Standard”), the ACC program, the USEPA/NHTSA Advanced Fuel Economy, the HD I/M program, and the Heavy-Duty Omnibus Regulation. While EMFAC2021 incorporates reductions associated with the ACT regulation this analysis assumes that all Project-related delivery trucks are diesel-fueled. Hence, the United States Congress’ and Senate’s recent action110 to disapprove California’s CAA waiver for ACT regulation does not impact this analysis. Additionally, EMFAC2021 does not include the ACC II regulation;111 therefore, GHG reductions associated with this regulation are not included in this analysis.

4.3.2.1 Estimating Mobile Source Emissions
Mobile source emissions calculation requires trip rates, trip lengths, and idle time for each on-road vehicle trip type associated with the proposed Project (e.g., customer and employee vehicles and delivery trucks). Additionally, the operational time for TRU engines that are mounted on some of the trailers delivered to the warehouse is required to estimate exhaust emissions from TRUs. The following sections describe the methodology to derive the necessary inputs for these calculations.

On-Road Vehicle Trip Generation Rates
The total trip generation rates for customer and employee vehicles were calculated as the sum of Project trip generation and latent demand trip generation estimates provided by Kittelson.112 As shown in Table 4-6, the annual average trips for customer and employee vehicles were estimated using the daily weekday and weekend trip rates. The annual average trips for delivery trucks were estimated using the weekly trip rates provided by the 109Kittelson & Associates. 2025. Foothill Ranch Costco Focused Transportation Impact Study. November. 110CARB. CARB Chair Liane Randolph responds to illegal and unconstitutional approval of Congressional Review Act resolutions by the U.S. Senate. Available at: https://ww2.arb.ca.gov/news/carb-chair-liane-randolph-respondsillegal-and-unconstitutional-approval-congressional-review. Accessed: October 2025. 111 In May 2025, the United States Congress and Senate voted to disapprove California’s Clean Air Act waiver for ACC II regulation using the Congressional Review Act. In response to this action, CARB stated that they “will pursue every available remedy to challenge these actions” and Governor Newson announced that California would join a 11-state coalition to advance clean cars.
112Kittelson & Associates. 2025. Foothill Ranch Costco Focused Transportation Impact Study. November.

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Project team (Table 4-6). The number of TRU equipped trailers that are brought on-site by warehouse delivery trucks and the trip generation rates for warehouse and tire center delivery trucks are based on Project-specific estimates, and presented in Appendix C.

Vehicle Miles Traveled
The VMT of customer and employee vehicles was provided by Kittelson.113 As shown in Table 4-6, the Project VMT for customer and employee vehicles would be negative. The VMT of delivery trucks is calculated as the product of trip rates and trip lengths (Table 4-6). The trip length for delivery trucks is based on Project-specific estimates.

Fleet Mix
The CalEEMod default fleet mix for customer and employee vehicles was adjusted using the default VMT distribution for vehicle technology/fuel categories in EMFAC2021 for Orange County to determine the Project-specific fleet mix of the vehicles visiting the Project (Table C-1 in Appendix C). Customer and employee vehicles primarily represent vehicles used by patrons and employees of the warehouse and include gasoline, plug-in hybrid, electricity, natural gas, and diesel-fueled vehicles. This analysis assumed that customer and employee vehicles did not include heavy heavy-duty trucks or buses. All delivery trucks were assumed to be diesel-fueled heavy heavy-duty diesel trucks.

Mobile Source Emission Factors
Default EMFAC2021 emission factors for the year 2027 were used for customer and employee vehicles. The CalEEMod run for customer and employee vehicles is presented in Appendix A-1.

Delivery truck emission factors for diesel-fueled heavy heavy-duty trucks were obtained from the default EMFAC2021 output for Orange County – South Coast for the year 2027. Refer to Table C-2 in Appendix C for further details. The CalEEMod run for delivery trucks is presented in Appendix A-2.

Exhaust emission factors for TRUs were calculated using OFFROAD2021 outputs for in-State and out-of-State trailer TRUs operating in Orange County as shown in Table C-3 in Appendix C.

TRU Operational Time
The total operational time for each TRU equipped trailer that is brought on-site by a warehouse delivery truck is estimated as the sum of the on-site truck idling time and the travel time for the truck round trip (Table C-4 in Appendix C). Annual operational duration of TRUs was estimated based on total operational time per transport refrigeration unit and the total number of TRUs visiting the Project site on an annual basis. Refer to Table C-4 in Appendix C for further details.

4.3.2.2 Mobile Source Emissions
The annual GHG emissions from area sources, energy usage, water, waste disposed, refrigerant, vegetation, stationary sources, and construction are presented in Appendix A-1. The annual GHG emissions from mobile sources are calculated as the sum of mobile emissions from customer and employee vehicles (presented in Appendix A-1), delivery trucks (presented in Appendix A-2), and TRUs (calculated using OFFROAD2021 emissions output in Table C-4 in Appendix C). These are summarized in Table 4-10. 113 Ibid.

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4.3.3 Water Supply, Treatment and Distribution
Indirect GHG emissions result from the production of electricity used to convey, treat, and distribute the proposed Project's water and wastewater. The amount of electricity required to convey, treat, and distribute water depends on the volume of water as well as the sources of the water. Additionally, direct CH4 and N2O emissions result from the treatment of wastewater.

The water usage and associated GHG emissions for the proposed Project are provided in the CalEEMod output files in Appendix A-1.

4.3.4 Energy Use
Energy usage within buildings (e.g., electricity and natural gas) contribute to the proposed Project’s GHG inventory. Combustion of any type of fuel emits CO2 and other GHGs directly into the atmosphere; these emissions are considered direct emissions associated with a building. GHGs are also emitted during the generation of electricity from fossil fuels; these emissions are considered as indirect emissions. Ramboll utilized CalEEMod default assumptions to calculate the annual natural gas use for the proposed Project’s land uses, which includes natural gas usage from water heating, primary heating, cooking, cooling, refrigeration, and other miscellaneous end uses.

To estimate GHG emissions from the natural gas and electricity usage for the proposed Project, Ramboll utilized CalEEMod default assumptions, which incorporate 2019 Title 24 Standards.

The energy usage and associated GHG emissions for the proposed Project are provided in the CalEEMod output files in Appendix A-1.

4.3.5 Solid Waste
Municipal solid waste (MSW) is the amount of material that is disposed of by landfilling, recycling, or composting. CalEEMod calculates the indirect GHG emissions associated with waste that is disposed of at a landfill. The program uses annual waste disposal rates from the CalRecycle data for individual land uses. CalEEMod uses the overall California Waste Stream composition to generate the necessary types of different waste disposed into landfills. The program quantifies the GHG emissions associated with the decomposition of the waste, which generates methane based on the total amount of degradable organic carbon.

The program quantifies the CO2 emissions associated with the combustion of methane, if applicable. Default landfill gas concentrations were used as reported in Section 2.4 of AP-42.

The IPCC has a similar method to calculate GHG emissions from MSW in its 2006 Guidelines for National Greenhouse Gas Inventories.

Solid waste generation associated with the proposed Project is based on default values for waste generation in CalEEMod. The waste generation and associated GHG emissions can be found in the CalEEMod output files in Appendix A-1.

4.3.6 Refrigerant Use
The proposed Project includes refrigerant use for warehouse operations, based on default values in CalEEMod. The resulting GHG emissions are provided in the CalEEMod output file in Appendix A-1.

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4.3.7 Stationary Sources
The proposed Project includes one diesel-powered emergency generator, rated at 95 horsepower, to support warehouse operations. Testing and maintenance of the generator would remain below 200 hours per year114 or 1 hour on any given day (Table 4-7).

Emissions from emergency generator operation were estimated using default assumptions in CalEEMod. In the absence of a CalEEMod default, the N2O emission factor for natural gas fuel was referenced from the USEPA Emission Factors for Greenhouse Gas Inventories (Table C-5 in Appendix C).115 The resulting GHG emissions estimates are provided in the CalEEMod output file in Appendix B-1.

4.3.8 Vegetation Changes
Vegetation changes that occur as a result of land use development constitute a change in the carbon sequestration capacity of a project site. The changes in vegetation are presented in Table 4-9. GHG emissions associated with vegetation changes are estimated in the CalEEMod output for the proposed Project operation in Appendix A-1.

4.4 Total Annual Operational Emissions
As shown in Table 4-10, the total emissions are 962 MT CO2e per year. The operational GHG emissions for the proposed Project are 932 MT CO2e per year. The total emissions from the proposed Project’s construction in 2026 and 2027 is 891 MT CO2e, which was amortized over a typical project lifetime of 30 years, to estimate the total annual GHG emissions from construction (29.7 MT CO2e per year).
116 Area, energy, mobile, and stationary source
emissions were estimated using CalEEMod® (Appendix A-1 and Appendix A-2) except for TRU emissions, which were calculated separately in Table C-4 in Appendix C. 114 Per SCAQMD Rule 1110.2, emergency standby engines must not operate more than 200 hours a year. 115 USEPA Emission Factors for Greenhouse Gas Inventories. Available at:
https://www.epa.gov/system/files/documents/2025-01/ghg-emission-factors-hub-2025.pdf. Accessed:

October 2025.
116 This approach to one-time construction and vegetation change GHG emissions is based on the GHG Threshold Working Group Meeting #13 Minutes from August 26, 2009. Available at: http://www.aqmd.gov/docs/defaultsource/ceqa/handbook/greenhouse-gases-(ghg)-ceqa-significance-thresholds/year-2008-2009/ghg-meeting13/ghg-meeting-13-minutes.pdf. Accessed: October 2025.

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5. PROJECT IMPACTS IN CONTEXT
This section assesses the significance of the proposed Project’s emissions for purposes of CEQA.

5.1 Threshold 1: Would the project generate GHG emissions, either directly or indirectly, that may have a significant impact on the environment? As noted in Section 3.2, in the absence of a quantitative GHG threshold from SCAQMD, this Technical Report assesses significance of the proposed Project’s GHG impacts for Threshold 1 against the SCAQMD draft screening level (3,000 MT CO2e/yr).

Total GHG emissions for the proposed Project construction are summarized in Table 4-10.

In the absence of a construction-specific GHG screening level, the emissions from construction were amortized over a typical project lifetime of 30 years, to estimate the total annual GHG emissions. These amortized emissions were combined with the operational emissions and compared to the SCAQMD draft screening level, which is described in further detail below.

Please note, the proposed Project includes design features that are not quantified in this analysis. Firstly, the Project would include 12 direct current fast charging (DCFC) EV charging stations (including two accessible ADA stalls) which would reduce the operational GHG emissions beyond the levels modeled in this analysis (Section 4.4) by replacing conventionally fueled VMT with EV miles traveled. Secondly, the Project will install solar panels which will generate renewable electricity and will displace some of the electricity used by the Project. This would further reduce the operational GHG emissions beyond levels modeled in this analysis (Section 4.4) by decreasing the average carbon intensity of the electricity used by the Project.

The Project’s annual operational GHG emissions were estimated to be 932 MT CO2e per year (Table 4-10). The amortized construction emissions were added to the Project’s annual operational GHG emissions, and the combined emissions were estimated to be 962 MT CO2e per year (Table 4-10). These emissions are below SCAQMD’s draft GHG emissions screening level (3,000 MT CO2e/yr). Therefore, the GHG emissions associated with the construction and operation of the proposed Project would not have a significant impact on the environment.

5.2 Threshold 2: Would the project conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions of GHGs? As noted in Section 3.2, this Technical Report assesses the significance of the proposed Project’s GHG impacts for Threshold 2 based on whether it conflicts with the 2022 Scoping Plan Update,117 the current RTP/SCS for SCAG,
118 and the City of Lake Forest General
Plan.119
117CARB. 2022. 2022 CARB Scoping Plan Update – Appendix D, Local Actions. Available at:
https://ww2.arb.ca.gov/sites/default/files/2022-11/2022-sp-appendix-d-local-actions.pdf. Accessed:

October 2025.
118SCAG. A Plan For A Brighter Future. Available at: https://scag.ca.gov/connect-socal. Accessed: October 2025. 119 City of Lake Forest. 2020. General Plan. June. Available at:
https://www.lakeforestca.gov/departments/community_development/planning/plans_and_standard_guidelines.p hp#undefined. Accessed: October 2025.

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5.2.1 2022 Scoping Plan Update
As discussed in Section 2.2.2.2, the 2022 Scoping Plan Update has a table of priority GHG reduction strategies that can be utilized by local governments. The three main priority areas addressed in this table are “Transportation Electrification”, “VMT Reduction”, and “Building Decarbonization”.120 These measures represent the core strategies that local jurisdictions in California can implement to reduce GHGs in alignment with State goals.

The proposed Project would not conflict with the implementation of the 2022 Scooping Plan Update and Statewide Emission Reduction Targets and would include Project features that would support aspects of the 2022 Scoping Plan Update.

As noted above, the Project will include 12 DCFC chargers for plug-in electric vehicles as part of the Project design. This directly supports the “Transportation Electrification” priority area by providing a convenient, low-cost EV charging station to members which would in turn replace conventionally fueled VMT with EV miles traveled.

The second priority area of the Scoping Plan is “VMT Reduction”. The traffic analysis for this Project found that the Project would result in a net reduction in VMT across the region.

Furthermore, the Project is expected to serve the existing population of the area by providing more convenient access to Costco services. The Project will be located in a central location that will allow customers to have multiple needs served in one trip, including but not limited to: eye exams, purchase of household goods and groceries, and tire service.

Additionally, the Project would be an infill development located near existing commercial developments and would therefore support the preservation of natural and working lands and compact infill development.

Lastly, the Project will implement a number of measures to reduce energy usage and will incorporate sustainability features per the California Title 24 energy requirements. The Project will meet the California Green Building Code requirements which includes a number of green building practices to reduce energy use. These practices are listed below and would further support the “Building Decarbonization” priority area of the 2022 Scoping Plan Update.121
• Parking lot light standards are designed in order to provide even light distribution, and utilize less energy compared to a greater number of fixtures at lower heights. The use of LED lamps provides a higher level of perceived brightness with less energy than other lamps such as high pressure sodium.
• New and renewable building materials are typically extracted and manufactured within the region.
• The use of pre-manufactured building components, including structural framing and metal panels, helps to minimize waste during construction. • Pre-manufactured metal wall panels with insulation carry a higher R-Value and greater solar reflectivity to help conserve energy. Building heat absorption is further reduced by a decrease in the thermal mass of the metal wall when compared to a typical masonry block wall.
120CARB. 2022. Final 2022 Scoping Plan Update and Appendices. December. Available at:
https://ww2.arb.ca.gov/our-work/programs/ab-32-climate-change-scoping-plan/2022-scoping-plan-documents.

Accessed: October 2025.
121 Please note that this analysis conservatively does not quantify the benefit of these Project features.

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• Costco uses a reflective cool roof material to produce lower heat absorption and thereby lowering energy requirements during the hot summer months. This roofing material meets the requirements for the EPA’s Energy Star energy efficiency program. • The irrigation system includes the use of deep root watering bubblers for parking lot trees to minimize usage and ensure that water goes directly to the intended planting areas.
• Storm water management plans are designed to maintain quality control and storm water discharge rates.
• Use of native species vegetation and drip irrigation systems greatly reduces potable water consumption.
• High-efficiency restroom fixtures achieve a 40% decrease and water savings over U.S. standards by using high-efficient restroom fixtures.
• Commissioning of mechanical systems to ensure the system is functioning as designed. • HVAC comfort systems are controlled by a computerized building management system to maximize efficiency.
• HVAC units are high-efficiency direct ducted units.
• HVAC units have phased out the use of hydrochlorofluorocarbons completely. Long before the Montreal Protocol timeline.
• Parking lot and exterior lights are controlled by a centrally controlled Energy Management system.
• Lighting is controlled by the overall Project energy management system. • High-efficiency light source and ballasts (LED) and bi-level switching for fluorescent fixtures are used.
• Energy efficient Transformers.
• Use of variable speed motors on make-up air units and booster pumps. • Gas water heaters are direct vent and 94% efficient or greater. • Main Building structure is a pre-engineered system that uses 100% recycled steel materials and is designed to minimize the amount of material utilized. • Roof material is recycled standing seam metal panel, designed to maximum efficiency for spanning the structure.
• When masonry and concrete are used, the materials purchased are local to the Project minimizing the transportation and impact to local road networks. • Construction waste is recycled whenever possible.
• Floor sealant is No-VOC and represents over 80% of the floor area. • CO2 is monitored throughout the warehouse.
• Extensive recycling/reuse program is implemented for warehouse and office space including tires, cardboard, grease, plastics and electronic waste. • Use of plastic shopping bags is avoided.

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• Suppliers are required to reduce packaging and consider alternative packaging solutions. • Distribution facilities are strategically located to minimize miles traveled for delivery.

Deliveries are made in full trucks.
• All Costco trucks are equipped with an engine idle shut off timer.

Lastly, as noted in Section 5.1, the Project will install solar panels which will generate renewable electricity and will displace some of the electricity used by the Project. This would support the “Building Decarbonization” priority area as well by decreasing the average carbon intensity of the electricity used by the Project.

Based on the Project elements described above, the Project would not interfere with the implementation of the 2022 Scoping Plan Update and would include elements that support the goals of the plan. Refer to Table D-1 in Appendix D for further details on the analysis of the 2022 Scoping Plan Update.

5.2.2 Connect SoCal 2024 Plan
The proposed Project would not conflict with the State’s GHG reduction goals and strategies as discussed in the SCAG’s Connect SoCal 2024 Plan122 (the current RTP/SCS for the region), which fall into four main categories: Mobility, Communities, Environment, and Economy.

The proposed Project would not conflict with the implementation of the SCAG’s Connect SoCal 2024 Plan and has several elements that are expected to support the main categories in SCAG’s Connect SoCal 2024 Plan. The Project would create new employment opportunities and is located near an OCTA bus route, therefore placing jobs that are accessible via public transit, in line with the “Economy” category of the Connect SoCal 2024 Plan. In addition, the proposed Project is planned to have many energy-saving design features, as discussed in Section 5.2.1. This would support the “Environment” category of the SCAG’s Connect SoCal 2024 Plan. Lastly, per the conclusions of the Kittelson Transportation Impact Study,123 the proposed Project would result in a net negative VMT and therefore would not impede the “Mobility” and “Communities” categories of the SCAG’s Connect SoCal 2024 Plan. Refer to Table D-2 in Appendix D for further details on the analysis of the SCAG’s Connect SoCal 2024 Plan.

5.2.3 City of Lake Forest General Plan
The proposed Project would not conflict with the City of Lake Forest General Plan, which includes the following main elements: land use and design, mobility, economic development, recreation and resources, public safety, public facilities, and health and wellness elements.

The Project is expected to serve the existing population of the area by providing more convenient access to Costco services. The Project will be located in a central location that will allow customers to have multiple needs served in one trip, including but not limited to: eye exams, purchase of household goods and groceries, and tire service. Additionally, the Project would be an infill development located near existing commercial and residential developments, and would be located near existing transit facilities which would support numerous policies within the General Plan, including “RR-4.2: Land Use Planning”, “RR-4.3:

Development,” and “RR-4.5 Public Transit.” The Project would also include EV charging facilities, as noted in Section 5.1. These chargers would support the policy “RR-4.9: GHG Reduction” by providing a convenient, low-cost EV charging station to members which would 122SCAG. Connect SoCal 2024 Plan. Available at: https://scag.ca.gov/connect-socal. Accessed: October 2025. 123Kittelson & Associates. 2025. Foothill Ranch Costco Focused Transportation Impact Study. November.

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in turn replace conventionally fueled VMT with EV miles traveled therefore reducing the GHG emissions of vehicle miles traveled in the region.

Based on the Project elements described above, the Project would not interfere with the implementation of the Lake Forest General Plan and would include elements that support the goals of the plan. Refer to Table D-3 in Appendix D for further details on the analysis of the Lake Forest General Plan, which assesses the policies and actions.

5.3 Summary
As noted in the previous sections, the proposed Project would not conflict with the 2022 Scoping Plan Update, SCAG’s RTP/SCS, nor the City of Lake Forest’s General Plan. Therefore, the proposed Project’s GHG emissions will be less than significant in the context of Threshold 2. In this context, and based on the analysis above, the proposed Project’s would be less than significant with respect to Threshold 2.

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Table 4-1. Construction Schedule - Proposed Project
Costco Foothill RanchLake Forest, California
DRAFT
CalEEMod
®
Phase Typ
e1
Construction
Phase Name1 Start Date1 End Date1
Phase Duration2
(da
y
s)
Demolition Demolition 10/5/2026 11/28/2026 48
Site Preparation Site Preparation 11/29/2026 12/12/2026 12 Grading Grading 12/13/2026 2/27/2027 66
Building Construction 1/23/2027 6/29/2027 135
Concrete Pour 1/23/2027 5/21/2027 102
Paving Paving 5/22/2027 6/11/2027 18
Architectural Coating Architectural Coating 5/17/2027 6/29/2027 38 Notes:

Abbreviations:CalEEMod
® - California Emissions Estimator Model
Building Construction3
3 The Building Construction phases includes a concrete pour subphase which begins on the first day of Building Construction phase and ends the day before the Paving phase begins.
1 Construction phases and duration are based on Project-specific information. 2 The construction work week was assumed to be 6 days per week.

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Table 4-2. Construction Equipment Assumptions
Costco Foothill RanchLake Forest, California
DRAFT
CalEEMod®
Phase Type
Construction
Phase Name Equipment Type
Number of
Equipment per
day1
Hours per
day1
Horsepower1
(hp) Load Factor1
Concrete/Industrial Saws 1 8 33 0.73Excavators 3 8 36 0.38Rubber Tired Dozers 2 8 367 0.40Rubber Tired Dozers 3 8 367 0.40Tractors/Loaders/Backhoes 4 8 84 0.37Excavators 2 8 36 0.38Graders 1 8 148 0.41Rubber Tired Dozers 1 8 367 0.40Scrapers 2 8 423 0.48Tractors/Loaders/Backhoes 2 8 84 0.37Cranes 1 7 367 0.29Forklifts 3 8 82 0.20Generator Sets 1 8 14 0.74Tractors/Loaders/Backhoes 3 7 84 0.37Welders 1 8 46 0.45Pavers 2 8 81 0.42Paving Equipment 2 8 89 0.36Rollers 2 8 36 0.38 Architectural Coating Architectural Coating Air Compressors 1 6 37 0.48 Notes:

Abbreviations:CalEEMod® - California Emissions Estimator Model hp - horsepower
Building Construction
&
Concrete Pour2
Building Construction
Paving Paving
2 The Building Construction phases includes the Concrete Pour subphase. The equipment in the Building Construction phase would be used throughout the duration of the Building Construction phase, including during the Concrete Pour subphase. 1 Number of equipment and operation hours based on CalEEMod® defaults. Available at: www.caleemod.com.

Demolition Demolition
Site Preparation Site Preparation
Grading Grading

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Table 4-3. Construction Material Movement
Costco Foothill RanchLake Forest, California
DRAFT
Construction Phase Name
Material Imported1
(yd3)
Material Exported1
(yd3)
Grading 26,795 0
Notes:
1 Soil import and export quantities based on Project-specific data.

Abbreviations:yd3 - cubic yard

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Table 4-4. Construction Demolition Assumptions
Costco Foothill Ranch
Lake Forest, California
DRAFT
Construction Phase Name
Material Exported1,2,3
(tons)
Demolition 23,295
Notes:
1 Demolition material based on Project-specific data.

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Table 4-5. Construction Trip Assumptions
Costco Foothill RanchLake Forest, California
DRAFT
CalEEMod®
Phase Type
Construction
Phase Name
Worker Trips
per Day1,2
Vendor Trips
per Day1,2
Hauling Trips
per Day1,3
Concrete Truck Trips
per Day1,4
Demolition Demolition 15 0 121 0
Site Preparation Site Preparation 18 0 0 0
Grading Grading 20 0 51 0
Building Construction
Building Construction
&
Concrete Pour5
53 27 0 8
Paving Paving 15 0 0 0
Architectural Coating Architectural Coating 21 0 0 0
Notes:

Abbreviations:CalEEMod® - California Emissions Estimator Model4 Project construction will include concrete pours during the Building Construction phase. For the purposes of this analysis, these concrete trucks are modeled as heavy-heavy duty vendor truck trips in CalEEMod®. The one-way trip length for the concrete truck trips is assumed to be the CalEEMod® default one-way trip length of 10.20 miles of vendor trips. 1 Trips are presented as one-way trips.2 Worker and vendor trips are based on CalEEMod® defaults. The one-way trip lengths for worker and vendor trips is assumed the CalEEMod®default values of 18.50 and 10.20 miles, respectively.5 The Building Construction phase includes a Concrete Pour subphase. The worker and vendor trips in the Building Construction phase would be used throughout the duration of the Building Construction phase, including during the Concrete Pour subphase. The concrete trucks trips would occur only during the Concrete Pour subphase.
3 Hauling trips reflect CalEEMod® defaults based on Project-specific estimates of material movement shown in Table 4-3 and Table 4-4. The one-way trip length for hauling trips is assumed to be the CalEEMod® default value of 20 miles.

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Table 4-6. Operational Mobile Sources Activity Data
Costco Foothill RanchLake Forest, California
Trip Type1
Average One-Way
Trip Length2
(miles)
Daily Trips3,4,5
(one-way trips/day)
Daily VMT3,6
(mi/day)
Weekly Trips7,8
(one-way trips/week)
Weekly VMT9,10
(mi/week)
Annual
Average Trips
(one-way trips/year)
Annual VMT
(VMT/year)
Customer and Employee Vehicles -- 13,893 -4,737 97,251 -33,159 5,070,945 -1,729,005Delivery Trucks (Warehouse and Tire Center) 37 24 888 144 5,328 7,509 277,817Notes:Abbreviations:mi - mileVMT - vehicle miles traveled1 The trip type is based on Project-specific information. The fleet mix and emission factors used for each trip type can be found in Appendix C.2 The trip length for the delivery trucks is based on Project-specific information. 5 Daily trips for the delivery trucks is based on Project-specific information. The warehouse will receive 10 truck deliveries per day. The tire center will receive deliveries from 2 trucks per week, so it is conservatively assumed that both of these trips could happen on a single day. Each delivery truck would result in two (2) one-way trips. 9 The weekly VMT for the customer and employee vehicles is estimated by multiplying the daily VMT by 7 days/week.10 The weekly VMT for the delivery vehicles is estimated by multiplying the weekly trips by the average one-way trip length.3 Trips and VMT for customer and employee vehicles was obtained from the Foothill Ranch Costco Focused Transportation Impact Study (Kittelson & Associates, Inc.).4 Daily trips for customer and employee vehicles are calculated as the sum of Costco warehouse total trip ends and latent demand trips (primary and diverted). Latent demand trips are trips associated with Costco members making more frequent trips to existing Costco locations due to latent demand. Please see Table 8 and Table 25 of the Foothill Ranch Costco Focused Transportation Impact Study for further details. 6 Daily VMT for the delivery trucks estimated as a product of the average trip length and number of daily trips.7 The weekly trips for customer and employee vehicles is estimated by multiplying the daily one-way trip rate by 7 days/week.8 The weekly trips for delivery vehicles is based upon Project-specific information. As noted above, there would be 2 tire center delivery trucks per week, and the weekly trip rate for the warehouse delivery truck was estimated by multiplying the daily one-way trip rate by 7 days/week. Each delivery truck would result in two (2) one-way trips. These were added together to give a total warehouse and tire center delivery truck weekly rate.

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Table 4-7. Operational Emergency Generator Assumptions
Costco Foothill RanchLake Forest, California
E
qui
pment Type Fuel Typ
e1 Number of Units Per Da
y1 Hours/Da
y1 Hours/Year2 Horse
power1 Load Factor3
Emergency Generator CNG 1 1 200 95 0.73
Abbreviations:

CalEEMod
® - California Emissions Estimator Model
CNG - compressed natural gasSCAQMD - South Coast Air Quality Management DistrictNotes:
1 Based on Project-specific information. Note, the emission factors used for assessing the emissions can be found in Appendix C.2 Per SCAQMD Rule 1110.2, emergency standby engines must not operate more than 200 hours a year. Available at:
https://www.aqmd.gov/docs/default-source/rule-book/reg-xi/r1110_2.pdf. Accessed: September 2025. 3 Based on CalEEMod
® defaults.

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Table 4-8. Utility GHG Emission Factor Associated with Renewable Portfolio Standard Costco Foothill Ranch
Lake Forest, California
2021 2022 2023 Average Units
CO2 Intensity Factor per Total Energy
Generated1 402 405 318 -- lbs CO2/MWh generated
% of Total Energy From RPS-Eligible
Renewables2 34.8% 35.8% 40.4% -- --
CO2 Intensity Factor per Total Non-RPSEligible Renewable Energy3 617 631 534 594 lbs CO2/MWh generated 2026 RPS (50%) -- -- -- 296.8 lbs CO2/MWh generated
2027 RPS (52%) -- -- -- 285.0 lbs CO2/MWh generated
Notes:

Abbreviations:

CO2 - carbon dioxide
GHG - greenhouse gas
lbs - pounds
MWh - megawatt-hour
RPS - Renewable Portfolio Standards
SCE - Southern California Edison
References:

SCE 2022 Sustainability Report. Available at: https://download.edison.com/406/files/20237/eix-2022-sustainabilityreport.pdf. Accessed: June 2025.

SCE 2023 Sustainability Report. Available at: https://download.edison.com/406/files/20245/eix-2023-sustainabilityreport.pdf. Accessed: June 2025.

SCE 2024 Sustainability Report. Available at:
https://download.edison.com/406/files/20255/202506060031/2024%20Sustainability%20Report.pdf. Accessed:

July 2025.

Senate Bill 100. Available at: https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=201720180SB100.

Accessed: June 2025.

Energy Generated (MWh)
Calculated Intensity Factors for Total Energy Delivered4 1 Obtained from SCE's 2023 and 2024 Sustainability Reports. Note that 2024 values are not provided because they are subject to regulatory approval and verification at the time of this report preparation. 2 Obtained from SCE's 2022, 2023, and 2024 Sustainability Reports. 3 The emissions metric presented here is calculated based on the total CO2 emissions for total energy generated divided by the energy generated from non-RPS-eligible renewable sources. 4 The intensity factors for default RPS assumption are calculated by multiplying the percentage of energy delivered from non-RPS-eligible renewable energy by the CO2 emissions per total non-RPS-eligible renewable energy metric calculated above. The emission factors presented here are 52% RPS for 2027 and 60% RPS for 2030 per Senate Bill 100. The estimate provided here assumes that RPS-Eligible renewable energy sources do not result in any CO2 emissions.

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Table 4-9. Vegetation Land Use Change Assumptions
Costco Foothill RanchLake Forest, California
Vegetation Land Use Type1
Vegetation
Soil Type2
CO2 Accumulation3
(MT CO2e/acre/yr) Acres, Existing Condition4 Acres, Proposed Project4 Other Alfisols 0.82 1.31 1.44Urban Other 0.0 14.97 14.84 CO2 Accumulation3
(MT CO2e/acre/yr) Acres, Existing Condition4 Acres, Proposed Project4

0.48 1.31 1.44
0 14.97 14.84
Notes:

Abbreviations:CalEEMod
® - California Emissions Estimator Model
CO2 - carbon dioxide
CO2e - carbon dioxide equivalentMT - metric tonUC Davis - University of California, Davisyr - year 4 Acreage of vegetation cover is based on Project-specific information.

Soil Carbon AccumulationAbove and Belowground Biomass Carbon Accumulation Cover Type
GrasslandUrban
2 Vegetation Soil Type at the Project location was determined using UC Davis' SoilWeb online geospatial tool. 1 Vegetation Land Use Type "Other" was chosen as all other CalEEMod ® Vegetation Land Use Types do not fit the description of the Project site. 3 CO2 Accumulation is based on CalEEMod
® default values. The Vegetation Land Use Type, "Other", does not have a CalEEMod ® default CO2
Accumulation value for Alfisols. Therefore, the CO2 Accumulation for Alfisols under the Vegetation Land Use Type, Other, was estimated as the minimum of CO2 Accumulation for Alfisols for all available Land Use Types.

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Table 4-10. Annual Average Greenhouse Gas Emissions for Project Operation Costco Foothill Ranch
Lake Forest, California
Emissions Category
Annual GHG Emissions
(MT CO2e/yr)1,2
Area Sources3 3.4
Energy Usage3 326
Mobile3,4,5 348
Stationary Sources3 5.1
Water3 28
Waste Disposed3 222
Refrigerant3 0.1
Vegetation3 -0.17
Operational Sub-Total 932
Construction Amortized6,7 29.7
Total Emissions8 962
SCAQMD Draft Screening Level9 3,000
Exceeds Threshold? NO
Notes:

Abbreviations:

CalEEMod® - CALifornia Emissions Estimator MODel
CH4 - methane
CO2 - carbon dioxide
CO2e - carbon dioxide equivalents
GHG - greenhouse gases
MT - metric tons
N2O - nitrous oxide
SCAQMD - South Coast Air Quality Management District
TRU - transport refrigeration unit
yr - year
9 In the absence of a quantitative GHG threshold from SCAQMD, this Technical Report assesses significance of the Proposed Project’s GHG impacts for Threshold 1 against the SCAQMD draft screening level (3,000 MT CO2e/yr). This is further discussed in Section 3 of the GHG Technical Report.
5 TRU emissions obtained from Table C-3 in Appendix C.
8 Sum of amortized one-time emissions and operational sub-total emissions. 7 One-time emissions from construction was amortized over a 30-year period. 1 Emissions are presented as CO2e, which include CO2, CH4, and N2O emissions, weighted by their respective global warming potentials.
2 Emissions totals may not add up due to rounding. Emissions shown as zero may be non-zero values; however, they are below a meaningful reporting level for this analysis. 3 Obtained from the CalEEMod® model run for project operation in Appendix A-1. 4 Obtained from the operational CalEEMod® model run for delivery trucks (see Appendix A-2). 6 Obtained from the CalEEMod® model run for project construction in Appendix A-1 and additional concrete truck idling emissions (Appendix B, Table B-2).

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APPENDIX A

CALEEMOD RUNS
DRAFT Foothill Ranch Costco Project
Greenhouse Gas Emissions Technical Report
Lake Forest, California
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1243
APPENDIX A-1

CALEEMOD RUN FOR PROJECT CONSTRUCTION AND OPERATION
DRAFT Foothill Ranch Costco Project
Greenhouse Gas Emissions Technical Report
Lake Forest, California
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Costco Foothill Ranch (Project) 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. Grading (2027) - Unmitigated

3.9. Building Construction (2027) - Unmitigated
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3.11. Concrete Pour (2027) - Unmitigated

3.13. Paving (2027) - Unmitigated

3.15. 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
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4.7.1. Unmitigated

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
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5.6. Dust Mitigation

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

5.10.2. 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 Item: 11
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5.14.1. Unmitigated

5.15. Operational Off-Road Equipment

5.15.1. Unmitigated

5.16. Stationary Sources

5.16.1. Emergency Generators and Fire Pumps

5.16.2. Process Boilers

5.17. User Defined

5.18. Vegetation

5.18.1. Land Use Change

5.18.1.1. Unmitigated

5.18.1. Biomass Cover Type

5.18.1.1. Unmitigated

5.18.2. Sequestration

5.18.2.1. Unmitigated

8. User Changes to Default Data

8.1. Justifications
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1. Basic Project Information

1.1. Basic Project Information
Data Field Value
Project Name Costco Foothill Ranch (Project)
Construction Start Date 10/5/2026
Operational Year 2027
Lead Agency —
Land Use Scale Project/site
Analysis Level for Defaults County
Windspeed (m/s) 2.5
Precipitation (days) 4.2
Location 26602 Towne Centre Dr, Foothill Ranch, CA 92610, USA County Orange
City Lake Forest
Air District South Coast AQMD
Air Basin South Coast
TAZ 6046
EDFZ 7
Electric Utility Southern California Edison
Gas Utility Southern California Gas
App Version 2022.1.1.32

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
Discount Club 165 1000sqft 3.8 165,070 62,553 — — —
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Parking Lot 12 Acre 12 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. 49 48 18 29 0.05 0.66 1.4 2.1 0.61 0.34 0.94 — 6,013 6,013 0.22 0.22 5.6 6,081 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 5.4 4.3 41 46 0.12 1.4 9.1 10 1.3 4.0 5.1 — 14,416 14,416 0.77 1.4 0.45 14,678 Average
Daily
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 5.8 5.6 8.5 11 0.02 0.29 1.7 1.9 0.27 0.43 0.63 — 3,038 3,038 0.14 0.21 1.2 3,090 Annual
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 1.1 1.0 1.5 1.9 < 0.005 0.05 0.30 0.34 0.05 0.08 0.12 — 503 503 0.02 0.03 0.20 512

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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2027 49 48 18 29 0.05 0.66 1.4 2.1 0.61 0.34 0.94 — 6,013 6,013 0.22 0.22 5.6 6,081 Daily -
Winter
(Max)
— — — — — — — — — — — — — — — — — —
2026 4.0 3.2 32 30 0.09 1.2 9.1 10 1.1 4.0 5.1 — 11,930 11,930 0.77 1.4 0.45 12,352 2027 5.4 4.3 41 46 0.12 1.4 5.8 7.2 1.3 2.0 3.3 — 14,416 14,416 0.71 0.82 0.31 14,678 Average
Daily
— — — — — — — — — — — — — — — — — —
2026 0.78 0.57 6.5 5.5 0.02 0.22 1.7 1.9 0.20 0.43 0.63 — 2,211 2,211 0.13 0.21 1.2 2,277 2027 5.8 5.6 8.5 11 0.02 0.29 1.0 1.3 0.27 0.34 0.61 — 3,038 3,038 0.14 0.16 1.2 3,090 Annual — — — — — — — — — — — — — — — — — —
2026 0.14 0.10 1.2 1.0 < 0.005 0.04 0.30 0.34 0.04 0.08 0.12 — 366 366 0.02 0.03 0.19 377 2027 1.1 1.0 1.5 1.9 < 0.005 0.05 0.19 0.25 0.05 0.06 0.11 — 503 503 0.02 0.03 0.20 512

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. 39 38 7.2 67 -0.01 0.08 -3.3 -3.3 0.07 -0.85 -0.78 406 888 1,294 43 0.86 -10 2,606 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 38 37 7.7 74 -0.01 0.06 -3.3 -3.3 0.06 -0.85 -0.79 406 1,022 1,428 43 0.90 0.51 2,768 Average
Daily
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 38 37 7.6 76 -0.01 0.07 -3.3 -3.3 0.07 -0.85 -0.78 406 976 1,382 43 0.89 -4.0 2,711 Annual
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 7.0 6.8 1.4 14 > -0.005 0.01 -0.61 -0.60 0.01 -0.15 -0.14 67 162 229 7.1 0.15 -0.65 449 Item: 11
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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 34 33 6.8 60 -0.01 0.04 -3.3 -3.3 0.04 -0.85 -0.81 — -1,217 -1,217 1.6 0.78 -11 -955 Area 5.3 5.2 0.06 7.2 < 0.005 0.01 — 0.01 0.01 — 0.01 — 30 30 < 0.005 < 0.005 — 30 Energy 0.03 0.01 0.27 0.22 < 0.005 0.02 — 0.02 0.02 — 0.02 — 1,955 1,955 0.22 0.02 — 1,967 Water — — — — — — — — — — — 23 68 92 2.4 0.06 — 169
Waste — — — — — — — — — — — 383 0.00 383 38 0.00 — 1,339 Refrig. — — — — — — — — — — — — — — — — 0.79 0.79
Stationa
ry
< 0.005 < 0.005 0.02 0.14 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 53 53 0.11 < 0.005 0.00 56 Vegetati
on
— — — — — — — — — — — — -1.0 -1.0 — — — -1.0
Total 39 38 7.2 67 -0.01 0.08 -3.3 -3.3 0.07 -0.85 -0.78 406 888 1,294 43 0.86 -10 2,606 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Mobile 34 33 7.4 74 -0.01 0.04 -3.3 -3.3 0.04 -0.85 -0.81 — -1,053 -1,053 1.8 0.82 -0.29 -763 Area 4.0 4.0 — — — — — — — — — — — — — — — —
Energy 0.03 0.01 0.27 0.22 < 0.005 0.02 — 0.02 0.02 — 0.02 — 1,955 1,955 0.22 0.02 — 1,967 Water — — — — — — — — — — — 23 68 92 2.4 0.06 — 169
Waste — — — — — — — — — — — 383 0.00 383 38 0.00 — 1,339 Refrig. — — — — — — — — — — — — — — — — 0.79 0.79
Stationa
ry
< 0.005 < 0.005 0.02 0.14 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 53 53 0.11 < 0.005 0.00 56 Vegetati
on
— — — — — — — — — — — — -1.0 -1.0 — — — -1.0
Total 38 37 7.7 74 -0.01 0.06 -3.3 -3.3 0.06 -0.85 -0.79 406 1,022 1,428 43 0.90 0.51 2,768 Item: 11
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Average
Daily
— — — — — — — — — — — — — — — — — —
Mobile 33 33 7.3 71 -0.01 0.04 -3.3 -3.3 0.04 -0.85 -0.81 — -1,096 -1,096 1.8 0.81 -4.7 -815 Area 4.9 4.8 0.04 4.9 < 0.005 0.01 — 0.01 0.01 — 0.01 — 20 20 < 0.005 < 0.005 — 20 Energy 0.03 0.01 0.27 0.22 < 0.005 0.02 — 0.02 0.02 — 0.02 — 1,955 1,955 0.22 0.02 — 1,967 Water — — — — — — — — — — — 23 68 92 2.4 0.06 — 169
Waste — — — — — — — — — — — 383 0.00 383 38 0.00 — 1,339 Refrig. — — — — — — — — — — — — — — — — 0.79 0.79
Stationa
ry
< 0.005 < 0.005 0.01 0.08 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 29 29 0.06 < 0.005 0.00 31 Vegetati
on
— — — — — — — — — — — — -1.0 -1.0 — — — -1.0
Total 38 37 7.6 76 -0.01 0.07 -3.3 -3.3 0.07 -0.85 -0.78 406 976 1,382 43 0.89 -4.0 2,711 Annual — — — — — — — — — — — — — — — — — —
Mobile 6.1 5.9 1.3 13 > -0.005 0.01 -0.61 -0.60 0.01 -0.15 -0.15 — -181 -181 0.29 0.13 -0.79 -135 Area 0.90 0.88 0.01 0.90 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 3.3 3.3 < 0.005 < 0.005 — 3.4 Energy 0.01 < 0.005 0.05 0.04 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 324 324 0.04 < 0.005 — 326 Water — — — — — — — — — — — 3.9 11 15 0.40 0.01 — 28
Waste — — — — — — — — — — — 63 0.00 63 6.3 0.00 — 222
Refrig. — — — — — — — — — — — — — — — — 0.13 0.13
Stationa
ry
< 0.005 < 0.005 < 0.005 0.01 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 4.8 4.8 0.01 < 0.005 0.00 5.1 Vegetati
on
— — — — — — — — — — — — -0.17 -0.17 — — — -0.17
Total 7.0 6.8 1.4 14 > -0.005 0.01 -0.61 -0.60 0.01 -0.15 -0.14 67 162 229 7.1 0.15 -0.65 449

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) Item: 11
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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)
— — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

2.7 2.3 21 19 0.03 0.84 — 0.84 0.78 — 0.78 — 3,427 3,427 0.14 0.03 — 3,438 Demoliti
on
— — — — — — 6.7 6.7 — 1.0 1.0 — — — — — — —
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 Average
Daily
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.36 0.30 2.7 2.5 < 0.005 0.11 — 0.11 0.10 — 0.10 — 451 451 0.02 < 0.005 — 452 Demoliti
on
— — — — — — 0.88 0.88 — 0.13 0.13 — — — — — — —
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

0.07 0.05 0.50 0.46 < 0.005 0.02 — 0.02 0.02 — 0.02 — 75 75 < 0.005 < 0.005 — 75 Demoliti
on
— — — — — — 0.16 0.16 — 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 Offsite — — — — — — — — — — — — — — — — — —
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Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.05 0.05 0.05 0.68 0.00 0.00 0.20 0.20 0.00 0.05 0.05 — 186 186 < 0.005 0.01 0.02 188 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 0.81 0.12 10 4.4 0.06 0.11 2.2 2.3 0.11 0.62 0.72 — 8,318 8,318 0.63 1.3 0.44 8,726 Average
Daily
— — — — — — — — — — — — — — — — — —
Worker 0.01 0.01 0.01 0.09 0.00 0.00 0.03 0.03 0.00 0.01 0.01 — 25 25 < 0.005 < 0.005 0.04 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 0.11 0.02 1.4 0.58 0.01 0.01 0.29 0.30 0.01 0.08 0.09 — 1,094 1,094 0.08 0.17 0.95 1,148 Annual — — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 0.02 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 4.1 4.1 < 0.005 < 0.005 0.01 4.2 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 0.02 < 0.005 0.25 0.11 < 0.005 < 0.005 0.05 0.06 < 0.005 0.01 0.02 — 181 181 0.01 0.03 0.16 190

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)
— — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Item: 11
1256
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Off-Roa 3.7 3.1 29 29 0.05 1.2 — 1.2 1.1 — 1.1 — 5,298 5,298 0.21 0.04 — 5,316 d
Equipm
ent
Dust
From
Material
Movement
— — — — — — 7.7 7.7 — 3.9 3.9 — — — — — — —
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

0.12 0.10 0.96 0.95 < 0.005 0.04 — 0.04 0.04 — 0.04 — 174 174 0.01 < 0.005 — 175 Dust
From
Material
Movement
— — — — — — 0.25 0.25 — 0.13 0.13 — — — — — — —
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 0.02 0.17 0.17 < 0.005 0.01 — 0.01 0.01 — 0.01 — 29 29 < 0.005 < 0.005 — 29 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 Offsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Item: 11
1257
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Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.06 0.06 0.06 0.80 0.00 0.00 0.23 0.23 0.00 0.05 0.05 — 217 217 < 0.005 0.01 0.02 219 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 0.03 0.00 0.00 0.01 0.01 0.00 < 0.005 < 0.005 — 7.2 7.2 < 0.005 < 0.005 0.01 7.3 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 — 1.2 1.2 < 0.005 < 0.005 < 0.005 1.2 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)
— — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

3.6 3.0 27 28 0.06 1.1 — 1.1 1.0 — 1.0 — 6,599 6,599 0.27 0.05 — 6,621 Item: 11
1258
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Dust — — — — — — 3.6 3.6 — 1.4 1.4 — — — — — — —
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 Average
Daily
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.16 0.14 1.2 1.2 < 0.005 0.05 — 0.05 0.05 — 0.05 — 294 294 0.01 < 0.005 — 295 Dust
From
Material
Movement
— — — — — — 0.16 0.16 — 0.06 0.06 — — — — — — —
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

0.03 0.02 0.22 0.22 < 0.005 0.01 — 0.01 0.01 — 0.01 — 49 49 < 0.005 < 0.005 — 49 Dust
From
Material
Movement
— — — — — — 0.03 0.03 — 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)
— — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.07 0.07 0.07 0.91 0.00 0.00 0.26 0.26 0.00 0.06 0.06 — 248 248 < 0.005 0.01 0.02 251 Item: 11
1259
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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 0.34 0.05 4.3 1.9 0.02 0.04 0.92 0.96 0.04 0.26 0.30 — 3,480 3,480 0.26 0.55 0.18 3,650 Average
Daily
— — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 0.04 0.00 0.00 0.01 0.01 0.00 < 0.005 < 0.005 — 11 11 < 0.005 < 0.005 0.02 11 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 0.02 < 0.005 0.19 0.08 < 0.005 < 0.005 0.04 0.04 < 0.005 0.01 0.01 — 155 155 0.01 0.02 0.14 163 Annual — — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 0.01 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 1.9 1.9 < 0.005 < 0.005 < 0.005 1.9 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 0.04 0.02 < 0.005 < 0.005 0.01 0.01 < 0.005 < 0.005 < 0.005 — 26 26 < 0.005 < 0.005 0.02 27

3.7. Grading (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)
— — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

3.5 2.9 26 27 0.06 1.0 — 1.0 0.96 — 0.96 — 6,598 6,598 0.27 0.05 — 6,621 Dust
From
Material
Movement
— — — — — — 3.6 3.6 — 1.4 1.4 — — — — — — —
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 Item: 11
1260
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Average
Daily
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.48 0.40 3.5 3.7 0.01 0.14 — 0.14 0.13 — 0.13 — 899 899 0.04 0.01 — 902 Dust
From
Material
Movement
— — — — — — 0.49 0.49 — 0.19 0.19 — — — — — — —
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

0.09 0.07 0.64 0.68 < 0.005 0.03 — 0.03 0.02 — 0.02 — 149 149 0.01 < 0.005 — 149 Dust
From
Material
Movement
— — — — — — 0.09 0.09 — 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 Offsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.07 0.06 0.06 0.85 0.00 0.00 0.26 0.26 0.00 0.06 0.06 — 244 244 < 0.005 0.01 0.02 247 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 0.31 0.05 4.2 1.8 0.02 0.04 0.92 0.96 0.04 0.26 0.30 — 3,412 3,412 0.26 0.55 0.17 3,583 Average
Daily
— — — — — — — — — — — — — — — — — —
Worker 0.01 0.01 0.01 0.12 0.00 0.00 0.04 0.04 0.00 0.01 0.01 — 34 34 < 0.005 < 0.005 0.05 34 Item: 11
1261
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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 0.04 0.01 0.57 0.25 < 0.005 0.01 0.12 0.13 0.01 0.04 0.04 — 465 465 0.04 0.07 0.38 488 Annual — — — — — — — — — — — — — — — — — —
Worker < 0.005 < 0.005 < 0.005 0.02 0.00 0.00 0.01 0.01 0.00 < 0.005 < 0.005 — 5.6 5.6 < 0.005 < 0.005 0.01 5.6 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 0.10 0.04 < 0.005 < 0.005 0.02 0.02 < 0.005 0.01 0.01 — 77 77 0.01 0.01 0.06 81

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)
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

1.2 1.0 9.4 13 0.02 0.34 — 0.34 0.31 — 0.31 — 2,397 2,397 0.10 0.02 — 2,405 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

1.2 1.0 9.4 13 0.02 0.34 — 0.34 0.31 — 0.31 — 2,397 2,397 0.10 0.02 — 2,405 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
— — — — — — — — — — — — — — — — — —
Item: 11
1262
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Off-Roa 0.46 0.38 3.5 4.8 0.01 0.12 — 0.12 0.11 — 0.11 — 887 887 0.04 0.01 — 890 d
Equipm
ent
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

0.08 0.07 0.63 0.87 < 0.005 0.02 — 0.02 0.02 — 0.02 — 147 147 0.01 < 0.005 — 147 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 0.18 0.15 0.16 2.6 0.00 0.00 0.69 0.69 0.00 0.16 0.16 — 676 676 0.01 0.03 2.1 686 Vendor 0.07 0.02 0.83 0.41 0.01 0.01 0.23 0.24 0.01 0.06 0.07 — 833 833 0.04 0.11 2.0 870 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 0.18 0.15 0.16 2.2 0.00 0.00 0.69 0.69 0.00 0.16 0.16 — 644 644 0.01 0.03 0.06 651 Vendor 0.07 0.02 0.87 0.42 0.01 0.01 0.23 0.24 0.01 0.06 0.07 — 833 833 0.04 0.11 0.05 868 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 0.06 0.06 0.07 0.87 0.00 0.00 0.25 0.25 0.00 0.06 0.06 — 241 241 < 0.005 0.01 0.34 244 Vendor 0.02 0.01 0.32 0.15 < 0.005 < 0.005 0.09 0.09 < 0.005 0.02 0.03 — 308 308 0.02 0.04 0.32 321 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 0.01 0.16 0.00 0.00 0.05 0.05 0.00 0.01 0.01 — 40 40 < 0.005 < 0.005 0.06 40 Item: 11
1263
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Vendor < 0.005 < 0.005 0.06 0.03 < 0.005 < 0.005 0.02 0.02 < 0.005 < 0.005 < 0.005 — 51 51 < 0.005 0.01 0.05 53 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. Concrete Pour (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)
— — — — — — — — — — — — — — — — — —
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)
— — — — — — — — — — — — — — — — — —
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
— — — — — — — — — — — — — — — — — —
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 — — — — — — — — — — — — — — — — — —
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 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Vendor 0.03 0.01 0.39 0.19 < 0.005 < 0.005 0.08 0.08 < 0.005 0.02 0.02 — 288 288 0.02 0.05 0.54 303 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 Item: 11
1264
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Daily, — — — — — — — — — — — — — — — — — —
Winter
(Max)
Worker 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Vendor 0.03 0.01 0.40 0.19 < 0.005 < 0.005 0.08 0.08 < 0.005 0.02 0.02 — 288 288 0.02 0.05 0.01 303 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 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Vendor 0.01 < 0.005 0.11 0.05 < 0.005 < 0.005 0.02 0.02 < 0.005 0.01 0.01 — 81 81 0.01 0.01 0.06 85 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 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 — 0.00 0.00 0.00 0.00 0.00 0.00 Vendor < 0.005 < 0.005 0.02 0.01 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 < 0.005 — 13 13 < 0.005 < 0.005 0.01 14 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. 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

0.88 0.74 6.9 10.0 0.01 0.30 — 0.30 0.27 — 0.27 — 1,511 1,511 0.06 0.01 — 1,516 Paving 1.8 1.8 — — — — — — — — — — — — — — — —
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 Item: 11
1265
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Daily, — — — — — — — — — — — — — — — — — —
Winter
(Max)
Average
Daily
— — — — — — — — — — — — — — — — — —
Off-Roa
d
Equipm
ent

0.04 0.04 0.34 0.49 < 0.005 0.01 — 0.01 0.01 — 0.01 — 75 75 < 0.005 < 0.005 — 75 Paving 0.09 0.09 — — — — — — — — — — — — — — — —
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 0.09 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 12 12 < 0.005 < 0.005 — 12 Paving 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 Offsite — — — — — — — — — — — — — — — — — —
Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Worker 0.05 0.04 0.04 0.74 0.00 0.00 0.20 0.20 0.00 0.05 0.05 — 192 192 < 0.005 0.01 0.61 195 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 0.03 0.00 0.00 0.01 0.01 0.00 < 0.005 < 0.005 — 9.1 9.1 < 0.005 < 0.005 0.01 9.3 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 Item: 11
1266
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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 0.01 0.00 0.00 < 0.005 < 0.005 0.00 < 0.005 < 0.005 — 1.5 1.5 < 0.005 < 0.005 < 0.005 1.5 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

3.15. 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

0.14 0.11 0.83 1.1 < 0.005 0.02 — 0.02 0.02 — 0.02 — 134 134 0.01 < 0.005 — 134 Architect
ural
Coating
s
44 44 — — — — — — — — — — — — — — — —
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 0.09 0.12 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 14 14 < 0.005 < 0.005 — 14 Item: 11
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Architect 4.6 4.6 — — — — — — — — — — — — — — — —
ural
Coating
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 0.02 0.02 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 2.3 2.3 < 0.005 < 0.005 — 2.3 Architect
ural
Coating
s

0.84 0.84 — — — — — — — — — — — — — — — —
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 0.07 0.06 0.06 1.0 0.00 0.00 0.28 0.28 0.00 0.06 0.06 — 271 271 < 0.005 0.01 0.86 274 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 0.01 0.01 0.01 0.10 0.00 0.00 0.03 0.03 0.00 0.01 0.01 — 27 27 < 0.005 < 0.005 0.04 28 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 0.02 0.00 0.00 0.01 0.01 0.00 < 0.005 < 0.005 — 4.5 4.5 < 0.005 < 0.005 0.01 4.6 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 Item: 11
1268
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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

4. Operations Emissions Details

4.1. Mobile Emissions by Land Use

4.1.1. Unmitigated
Mobile source emissions results are presented in Sections 2.6. No further detailed breakdown of emissions is available.

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)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — — 1,266 1,266 0.15 0.02 — 1,275
Parking
Lot
— — — — — — — — — — — — 372 372 0.04 0.01 — 375
Total — — — — — — — — — — — — 1,638 1,638 0.19 0.02 — 1,650 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — — 1,266 1,266 0.15 0.02 — 1,275
Parking
Lot
— — — — — — — — — — — — 372 372 0.04 0.01 — 375
Total — — — — — — — — — — — — 1,638 1,638 0.19 0.02 — 1,650 Annual — — — — — — — — — — — — — — — — — —
Item: 11
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Discount — — — — — — — — — — — — 210 210 0.02 < 0.005 — 211 Club
Parking
Lot
— — — — — — — — — — — — 62 62 0.01 < 0.005 — 62
Total — — — — — — — — — — — — 271 271 0.03 < 0.005 — 273

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)
— — — — — — — — — — — — — — — — — —
Discount
Club

0.03 0.01 0.27 0.22 < 0.005 0.02 — 0.02 0.02 — 0.02 — 317 317 0.03 < 0.005 — 318 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 0.03 0.01 0.27 0.22 < 0.005 0.02 — 0.02 0.02 — 0.02 — 317 317 0.03 < 0.005 — 318 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club

0.03 0.01 0.27 0.22 < 0.005 0.02 — 0.02 0.02 — 0.02 — 317 317 0.03 < 0.005 — 318 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 0.03 0.01 0.27 0.22 < 0.005 0.02 — 0.02 0.02 — 0.02 — 317 317 0.03 < 0.005 — 318 Annual — — — — — — — — — — — — — — — — — —
Discount
Club

0.01 < 0.005 0.05 0.04 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 52 52 < 0.005 < 0.005 — 53 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 0.01 < 0.005 0.05 0.04 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 52 52 < 0.005 < 0.005 — 53 Item: 11
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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)
— — — — — — — — — — — — — — — — — —
Consum
er
Product
s

3.6 3.6 — — — — — — — — — — — — — — — —
Architect
ural
Coating
s

0.46 0.46 — — — — — — — — — — — — — — — —
Landsca
pe
Equipm
ent

1.3 1.2 0.06 7.2 < 0.005 0.01 — 0.01 0.01 — 0.01 — 30 30 < 0.005 < 0.005 — 30 Total 5.3 5.2 0.06 7.2 < 0.005 0.01 — 0.01 0.01 — 0.01 — 30 30 < 0.005 < 0.005 — 30 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Consum
er
Product
s

3.6 3.6 — — — — — — — — — — — — — — — —
Architect
ural
Coating
s

0.46 0.46 — — — — — — — — — — — — — — — —
Total 4.0 4.0 — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Item: 11
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Consum 0.65 0.65 — — — — — — — — — — — — — — — —
er
Product
Architect
ural
Coating
s

0.08 0.08 — — — — — — — — — — — — — — — —
Landsca
pe
Equipm
ent

0.16 0.15 0.01 0.90 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 3.3 3.3 < 0.005 < 0.005 — 3.4 Total 0.90 0.88 0.01 0.90 < 0.005 < 0.005 — < 0.005 < 0.005 — < 0.005 — 3.3 3.3 < 0.005 < 0.005 — 3.4

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)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 23 68 92 2.4 0.06 — 169
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 23 68 92 2.4 0.06 — 169
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 23 68 92 2.4 0.06 — 169
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 23 68 92 2.4 0.06 — 169
Item: 11
1272
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Annual — — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 3.9 11 15 0.40 0.01 — 28
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 3.9 11 15 0.40 0.01 — 28

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)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 383 0.00 383 38 0.00 — 1,339
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 383 0.00 383 38 0.00 — 1,339 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 383 0.00 383 38 0.00 — 1,339
Parking
Lot
— — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00
Total — — — — — — — — — — — 383 0.00 383 38 0.00 — 1,339 Annual — — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 63 0.00 63 6.3 0.00 — 222
Item: 11
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Parking — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Lot
Total — — — — — — — — — — — 63 0.00 63 6.3 0.00 — 222

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)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — — — — — — 0.79 0.79
Total — — — — — — — — — — — — — — — — 0.79 0.79
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — — — — — — 0.79 0.79
Total — — — — — — — — — — — — — — — — 0.79 0.79
Annual — — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — — — — — — 0.13 0.13
Total — — — — — — — — — — — — — — — — 0.13 0.13

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) Item: 11
1274
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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 — — — — — — — — — — — — — — — — — —

4.8. 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) 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)
— — — — — — — — — — — — — — — — — —
Emerge
ncy
Generat
or
< 0.005 < 0.005 0.02 0.14 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 53 53 0.11 < 0.005 0.00 56 Total < 0.005 < 0.005 0.02 0.14 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 53 53 0.11 < 0.005 0.00 56 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Emerge
ncy
Generat
or
< 0.005 < 0.005 0.02 0.14 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 53 53 0.11 < 0.005 0.00 56 Item: 11
1275
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Total < 0.005 < 0.005 0.02 0.14 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 53 53 0.11 < 0.005 0.00 56 Annual — — — — — — — — — — — — — — — — — —
Emerge
ncy
Generat
or
< 0.005 < 0.005 < 0.005 0.01 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 4.8 4.8 0.01 < 0.005 0.00 5.1 Total < 0.005 < 0.005 < 0.005 0.01 < 0.005 < 0.005 0.00 < 0.005 < 0.005 0.00 < 0.005 0.00 4.8 4.8 0.01 < 0.005 0.00 5.1

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

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 Item: 11
1276
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Daily,
Summer
(Max)
— — — — — — — — — — — — — — — — — —
Other — — — — — — — — — — — — -0.64 -0.64 — — — -0.64
Urban — — — — — — — — — — — — 0.00 0.00 — — — 0.00
Total — — — — — — — — — — — — -0.64 -0.64 — — — -0.64
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Other — — — — — — — — — — — — -0.64 -0.64 — — — -0.64
Urban — — — — — — — — — — — — 0.00 0.00 — — — 0.00
Total — — — — — — — — — — — — -0.64 -0.64 — — — -0.64
Annual — — — — — — — — — — — — — — — — — —
Other — — — — — — — — — — — — -0.11 -0.11 — — — -0.11
Urban — — — — — — — — — — — — 0.00 0.00 — — — 0.00
Total — — — — — — — — — — — — -0.11 -0.11 — — — -0.11

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)
— — — — — — — — — — — — — — — — — —
Grassla
nd
— — — — — — — — — — — — -0.38 -0.38 — — — -0.38
Urban — — — — — — — — — — — — 0.00 0.00 — — — 0.00
Total — — — — — — — — — — — — -0.38 -0.38 — — — -0.38
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Item: 11
1277
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Grassla — — — — — — — — — — — — -0.38 -0.38 — — — -0.38 nd
Urban — — — — — — — — — — — — 0.00 0.00 — — — 0.00
Total — — — — — — — — — — — — -0.38 -0.38 — — — -0.38
Annual — — — — — — — — — — — — — — — — — —
Grassla
nd
— — — — — — — — — — — — -0.06 -0.06 — — — -0.06
Urban — — — — — — — — — — — — 0.00 0.00 — — — 0.00
Total — — — — — — — — — — — — -0.06 -0.06 — — — -0.06

4.10.3. Avoided and Sequestered Emissions by Species - Unmitigated 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 — — — — — — — — — — — — — — — — — —
Item: 11
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Sequest — — — — — — — — — — — — — — — — — —
ered
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
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 10/5/2026 11/28/2026 6.0 48 —
Site Preparation Site Preparation 11/29/2026 12/12/2026 6.0 12 — Grading Grading 12/13/2026 2/27/2027 6.0 66 —
Building Construction Building Construction 1/23/2027 6/29/2027 6.0 135 — Concrete Pour Building Construction 1/23/2027 5/21/2027 6.0 102 — Paving Paving 5/22/2027 6/11/2027 6.0 18 —
Architectural Coating Architectural Coating 5/17/2027 6/29/2027 6.0 38 — Item: 11
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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 8.0 33 0.73
Demolition Excavators Diesel Average 3.0 8.0 36 0.38
Demolition Rubber Tired Dozers Diesel Average 2.0 8.0 367 0.40 Site Preparation Rubber Tired Dozers Diesel Average 3.0 8.0 367 0.40 Site Preparation Tractors/Loaders/Back
hoes
Diesel Average 4.0 8.0 84 0.37
Grading Excavators Diesel Average 2.0 8.0 36 0.38
Grading Graders Diesel Average 1.00 8.0 148 0.41
Grading Rubber Tired Dozers Diesel Average 1.00 8.0 367 0.40 Grading Scrapers Diesel Average 2.0 8.0 423 0.48
Grading Tractors/Loaders/Back
hoes
Diesel Average 2.0 8.0 84 0.37
Building Construction Cranes Diesel Average 1.00 7.0 367 0.29 Building Construction Forklifts Diesel Average 3.0 8.0 82 0.20 Building Construction Generator Sets Diesel Average 1.00 8.0 14 0.74 Building Construction Tractors/Loaders/Back
hoes
Diesel Average 3.0 7.0 84 0.37
Building Construction Welders Diesel Average 1.00 8.0 46 0.45 Paving Pavers Diesel Average 2.0 8.0 81 0.42
Paving Paving Equipment Diesel Average 2.0 8.0 89 0.36
Paving Rollers Diesel Average 2.0 8.0 36 0.38
Architectural Coating Air Compressors Diesel Average 1.00 6.0 37 0.48

5.3. Construction Vehicles
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5.3.1. Unmitigated
Phase Name Trip Type One-Way Trips per Day Miles per Trip Vehicle Mix Demolition Worker 15 19 LDA,LDT1,LDT2
Demolition Vendor — 10 HHDT,MHDT
Demolition Hauling 121 20 HHDT
Demolition Onsite truck — — HHDT
Site Preparation Worker 18 19 LDA,LDT1,LDT2
Site Preparation Vendor — 10 HHDT,MHDT
Site Preparation Hauling 0.00 20 HHDT
Site Preparation Onsite truck — — HHDT
Grading Worker 20 19 LDA,LDT1,LDT2
Grading Vendor — 10 HHDT,MHDT
Grading Hauling 51 20 HHDT
Grading Onsite truck — — HHDT
Building Construction Worker 53 19 LDA,LDT1,LDT2
Building Construction Vendor 27 10 HHDT,MHDT
Building Construction Hauling 0.00 20 HHDT
Building Construction Onsite truck — — HHDT
Concrete Pour Worker 0.00 19 LDA,LDT1,LDT2
Concrete Pour Vendor 8.2 10 HHDT
Concrete Pour Hauling 0.00 20 HHDT
Concrete Pour Onsite truck — — HHDT
Paving Worker 15 19 LDA,LDT1,LDT2
Paving Vendor — 10 HHDT,MHDT
Paving Hauling 0.00 20 HHDT
Paving Onsite truck — — HHDT
Architectural Coating Worker 21 19 LDA,LDT1,LDT2
Architectural Coating Vendor — 10 HHDT,MHDT
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Architectural Coating Hauling 0.00 20 HHDT
Architectural Coating Onsite truck — — HHDT

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 0.00 0.00 247,605 82,535 32,644

5.6. Dust Mitigation

5.6.1. Construction Earthmoving Activities
Phase Name Material Imported (cy) Material Exported (cy) Acres Graded (acres) Material Demolished (Ton of Debris)
Acres Paved (acres)
Demolition 0.00 0.00 0.00 23,295 0.00
Site Preparation — — 18 0.00 0.00
Grading 26,795 0.00 237 0.00 0.00
Paving 0.00 0.00 0.00 0.00 12

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
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Phase Name Land Use Area Paved (acres) % Asphalt
Paving Discount Club 0.00 0%
Paving Parking Lot 12 100%

5.8. Construction Electricity Consumption and Emissions Factors kWh per Year and Emission Factor (lb/MWh)
Year kWh per Year CO2 CH4 N2O
2026 0.00 297 0.03 < 0.005
2027 0.00 285 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 Total all Land Uses 13,893 13,893 13,893 5,070,945 -4,737 -4,737 -4,737 -1,729,005

5.10. Operational Area Sources

5.10.1. Hearths
Land Use Hearth Type Unmitigated (number) Mitigated (number) Discount Club Wood Fireplaces 0 0
Discount Club Gas Fireplaces 0 0
Discount Club Propane Fireplaces 0 0
Discount Club Electric Fireplaces 0 0
Discount Club No Fireplaces 0 0
Discount Club Conventional Wood Stoves 0 0
Discount Club Catalytic Wood Stoves 0 0
Discount Club Non-Catalytic Wood Stoves 0 0
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Discount Club Pellet Wood Stoves 0 0
Parking Lot Wood Fireplaces 0 0
Parking Lot Gas Fireplaces 0 0
Parking Lot Propane Fireplaces 0 0
Parking Lot Electric Fireplaces 0 0
Parking Lot No Fireplaces 0 0
Parking Lot Conventional Wood Stoves 0 0
Parking Lot Catalytic Wood Stoves 0 0
Parking Lot Non-Catalytic Wood Stoves 0 0
Parking Lot Pellet Wood Stoves 0 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)
undefined 0.00 0.00 247,605 82,535 32,644

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) Discount Club 1,621,213 285 0.0330 0.0040 988,265
Parking Lot 476,600 285 0.0330 0.0040 0.00
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5.12. Operational Water and Wastewater Consumption

5.12.1. Unmitigated
Land Use Indoor Water (gal/year) Outdoor Water (gal/year) Discount Club 12,227,151 810,710
Parking Lot 0.00 0.00

5.13. Operational Waste Generation

5.13.1. Unmitigated
Land Use Waste (ton/year) Cogeneration (kWh/year)
Discount Club 710 0.00
Parking Lot 0.00 0.00

5.14. Operational Refrigeration and Air Conditioning Equipment

5.14.1. Unmitigated
Land Use Equipment Type Refrigerant GWP Quantity (kg) Operations Leak Rate Service Leak Rate Times Serviced Discount Club Other commercial A/C
and heat pumps
R-410A 2,088 < 0.005 4.0 4.0 18
Discount Club Stand-alone retail
refrigerators and
freezers
R-134a 1,430 0.04 1.00 0.00 1.00

5.15. Operational Off-Road Equipment

5.15.1. Unmitigated

5.16. Stationary Sources
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5.16.1. Emergency Generators and Fire Pumps
Equipment Type Fuel Type Number per Day Hours per Day Hours per Year Horsepower Load Factor Emergency Generator CNG 1.00 1.00 200 95 0.73

5.16.2. Process Boilers

5.17. User Defined

5.18. Vegetation

5.18.1. Land Use Change

5.18.1.1. Unmitigated
Vegetation Land Use Type Vegetation Soil Type Initial Acres Final Acres Other Alfisols 1.3 1.4
Urban Other 15 15

5.18.1. Biomass Cover Type

5.18.1.1. Unmitigated
Biomass Cover Type Initial Acres Final Acres
Grassland 1.3 1.4
Urban 15 15

5.18.2. Sequestration

5.18.2.1. Unmitigated
Tree Type Number Electricity Saved (kWh/year) Natural Gas Saved (btu/year) Item: 11
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8. User Changes to Default Data

8.1. Justifications
Screen Justification
Characteristics: Utility Information CO2 emission factor estimated based upon RPS compliance.

Land Use Based on project-specific information.

Construction: Construction Phases Based on project-specific information.

Construction: Off-Road Equipment Concrete pour phase only includes concrete trucks.

Construction: Dust From Material Movement Construction material movement based on project-specific information. Watering 2x/day based on SCAQMD Rule 403, Table 1.

Construction: Trips and VMT Based on project-specific information.

Construction: Electricity CO2 emission factor estimated based upon RPS compliance.

Operations: Fleet Mix Based on project-specific information.

Operations: Generators + Pumps EF Based on project-specific information.

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APPENDIX A-2

CALEEMOD RUN FOR DELIVERY TRUCKS
DRAFT Foothill Ranch Costco Project
Greenhouse Gas Emissions Technical Report
Lake Forest, California
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Costco Foothill Ranch (Delivery Trucks) 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

2.4. Operations Emissions Compared Against Thresholds

2.5. Operations Emissions by Sector, 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
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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

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

5.9. Operational Mobile Sources
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5.9.1. Unmitigated

5.10. Operational Area Sources

5.10.1. Hearths

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

5.14.1. Unmitigated

5.15. Operational Off-Road Equipment

5.15.1. Unmitigated

5.16. Stationary Sources

5.16.1. Emergency Generators and Fire Pumps

5.16.2. Process Boilers
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5.17. User Defined

5.18. Vegetation

5.18.1. Land Use Change

5.18.1.1. Unmitigated

5.18.1. Biomass Cover Type

5.18.1.1. Unmitigated

5.18.2. Sequestration

5.18.2.1. Unmitigated

8. User Changes to Default Data

8.1. Justifications
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1. Basic Project Information

1.1. Basic Project Information
Data Field Value
Project Name Costco Foothill Ranch (Delivery Trucks)
Operational Year 2027
Lead Agency —
Land Use Scale Project/site
Analysis Level for Defaults County
Windspeed (m/s) 2.5
Precipitation (days) 4.2
Location 26602 Towne Centre Dr, Foothill Ranch, CA 92610, USA County Orange
City Lake Forest
Air District South Coast AQMD
Air Basin South Coast
TAZ 6046
EDFZ 7
Electric Utility Southern California Edison
Gas Utility Southern California Gas
App Version 2022.1.1.32

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
Discount Club 165 1000sqft 3.8 165,070 62,553 — — —
Parking Lot 12 Acre 12 0.00 0.00 — — —
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1.3. User-Selected Emission Reduction Measures by Emissions Sector No measures selected

2. Emissions Summary

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. 0.05 0.04 3.4 0.37 0.03 0.05 0.81 0.86 0.05 0.22 0.26 0.00 3,052 3,052 < 0.005 0.48 5.7 3,201 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 0.05 0.04 3.6 0.38 0.03 0.05 0.81 0.86 0.05 0.22 0.26 0.00 3,053 3,053 < 0.005 0.48 0.15 3,196 Average
Daily
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 0.04 0.04 3.1 0.32 0.02 0.04 0.69 0.73 0.04 0.19 0.23 0.00 2,616 2,616 < 0.005 0.41 2.1 2,741 Annual
(Max)
— — — — — — — — — — — — — — — — — —
Unmit. 0.01 0.01 0.56 0.06 < 0.005 0.01 0.13 0.13 0.01 0.03 0.04 0.00 433 433 < 0.005 0.07 0.35 454

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 0.05 0.04 3.4 0.37 0.03 0.05 0.81 0.86 0.05 0.22 0.26 — 3,052 3,052 < 0.005 0.48 5.7 3,201 Item: 11
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Area 0.00 0.00 — — — — — — — — — — — — — — — —
Waste — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Total 0.05 0.04 3.4 0.37 0.03 0.05 0.81 0.86 0.05 0.22 0.26 0.00 3,052 3,052 < 0.005 0.48 5.7 3,201 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Mobile 0.05 0.04 3.6 0.38 0.03 0.05 0.81 0.86 0.05 0.22 0.26 — 3,053 3,053 < 0.005 0.48 0.15 3,196 Area 0.00 0.00 — — — — — — — — — — — — — — — —
Waste — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Total 0.05 0.04 3.6 0.38 0.03 0.05 0.81 0.86 0.05 0.22 0.26 0.00 3,053 3,053 < 0.005 0.48 0.15 3,196 Average
Daily
— — — — — — — — — — — — — — — — — —
Mobile 0.04 0.04 3.1 0.32 0.02 0.04 0.69 0.73 0.04 0.19 0.23 — 2,616 2,616 < 0.005 0.41 2.1 2,741 Area 0.00 0.00 — — — — — — — — — — — — — — — —
Waste — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Total 0.04 0.04 3.1 0.32 0.02 0.04 0.69 0.73 0.04 0.19 0.23 0.00 2,616 2,616 < 0.005 0.41 2.1 2,741 Annual — — — — — — — — — — — — — — — — — —
Mobile 0.01 0.01 0.56 0.06 < 0.005 0.01 0.13 0.13 0.01 0.03 0.04 — 433 433 < 0.005 0.07 0.35 454 Area 0.00 0.00 — — — — — — — — — — — — — — — —
Waste — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Total 0.01 0.01 0.56 0.06 < 0.005 0.01 0.13 0.13 0.01 0.03 0.04 0.00 433 433 < 0.005 0.07 0.35 454

4. Operations Emissions Details

4.1. Mobile Emissions by Land Use

4.1.1. Unmitigated
Mobile source emissions results are presented in Sections 2.6. No further detailed breakdown of emissions is available.

4.2. Energy
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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)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

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)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

4.3. Area Emissions by Source
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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)
— — — — — — — — — — — — — — — — — —
Consum
er
Product
s

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

0.00 0.00 — — — — — — — — — — — — — — — —
Total 0.00 0.00 — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Consum
er
Product
s

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

0.00 0.00 — — — — — — — — — — — — — — — —
Total 0.00 0.00 — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Consum
er
Product
s

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

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

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)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —

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)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 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
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Total — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 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
Total — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00 Annual — — — — — — — — — — — — — — — — — —
Discount
Club
— — — — — — — — — — — 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
Total — — — — — — — — — — — 0.00 0.00 0.00 0.00 0.00 — 0.00

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)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Total — — — — — — — — — — — — — — — — — —
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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) 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 — — — — — — — — — — — — — — — — — —
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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

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 — — — — — — — — — — — — — — — — — —
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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 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
— — — — — — — — — — — — — — — — — —
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Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —
Daily,
Winter
(Max)
— — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —
Annual — — — — — — — — — — — — — — — — — —
Avoided — — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Sequest
ered
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
Remove
d
— — — — — — — — — — — — — — — — — —
Subtotal — — — — — — — — — — — — — — — — — —
— — — — — — — — — — — — — — — — — — —

5. Activity Data
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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 Total all Land Uses 24 24 24 7,509 888 888 888 277,817

5.10. Operational Area Sources

5.10.1. Hearths
Land Use Hearth Type Unmitigated (number) Mitigated (number) Discount Club Wood Fireplaces 0 0
Discount Club Gas Fireplaces 0 0
Discount Club Propane Fireplaces 0 0
Discount Club Electric Fireplaces 0 0
Discount Club No Fireplaces 0 0
Discount Club Conventional Wood Stoves 0 0
Discount Club Catalytic Wood Stoves 0 0
Discount Club Non-Catalytic Wood Stoves 0 0
Discount Club Pellet Wood Stoves 0 0
Parking Lot Wood Fireplaces 0 0
Parking Lot Gas Fireplaces 0 0
Parking Lot Propane Fireplaces 0 0
Parking Lot Electric Fireplaces 0 0
Parking Lot No Fireplaces 0 0
Parking Lot Conventional Wood Stoves 0 0
Parking Lot Catalytic Wood Stoves 0 0
Parking Lot Non-Catalytic Wood Stoves 0 0
Parking Lot Pellet Wood Stoves 0 0
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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)
undefined 0.00 0.00 247,605 82,535 32,644

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

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
Land Use Waste (ton/year) Cogeneration (kWh/year)
Discount Club 0.00 0.00
Parking Lot 0.00 0.00

5.14. Operational Refrigeration and Air Conditioning Equipment

5.14.1. Unmitigated
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5.15. Operational Off-Road Equipment

5.15.1. Unmitigated

5.16. Stationary Sources

5.16.1. Emergency Generators and Fire Pumps

5.16.2. Process Boilers

5.17. User Defined

5.18. Vegetation

5.18.1. Land Use Change

5.18.1.1. Unmitigated
Vegetation Land Use Type Vegetation Soil Type Initial Acres Final Acres

5.18.1. Biomass Cover Type

5.18.1.1. Unmitigated
Biomass Cover Type Initial Acres Final Acres

5.18.2. Sequestration

5.18.2.1. Unmitigated
Tree Type Number Electricity Saved (kWh/year) Natural Gas Saved (btu/year)

8. User Changes to Default Data
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8.1. Justifications
Screen Justification
Characteristics: Utility Information CO2 emission factor estimated based upon RPS compliance.

Land Use Based on project-specific information.

Operations: Fleet Mix Updated for delivery truck mobile emissions only.

Operations: Vehicle EF Emission factors for Diesel HHDTs were obtained from the default EMFAC2021 output for Orange County - South Coast calendar year 2027. HFC emission factors were kept as CalEEMod defaults.

Operations: Consumer Products Updated for delivery truck mobile emissions only.

Operations: Architectural Coatings Updated for delivery truck mobile emissions only.

Operations: Landscape Equipment Updated for delivery truck mobile emissions only.

Operations: Energy Use Updated for delivery truck mobile emissions only.

Operations: Water and Waste Water Updated for delivery truck mobile emissions only.

Operations: Solid Waste Updated for delivery truck mobile emissions only.

Operations: Refrigerants Updated for delivery truck mobile emissions only.

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1307

APPENDIX B

SUPPORTING EMISSION CALCULATIONS FOR PROJECT CONSTRUCTION DRAFT Foothill Ranch Costco Project
Greenhouse Gas Emissions Technical Report
Lake Forest, California
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List of Tables
Table B-1:

Table B-2:

Greenhouse Gas Emission Factors for Concrete Truck Idling Greenhouse Gas Emissions from Concrete Trucks Idling and On-Road Travel During Project Construction
DRAFT Foothill Ranch Costco Project
Greenhouse Gas Emissions Technical Report
Lake Forest, California
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Table B-1. Greenhouse Gas Emission Factors for Concrete Truck Idling Foothill Ranch Costco ProjectLake Forest, California
EMFAC
Vehicle
Class Fuel Typ
e
Concrete Truck
Fleet Mix 1
CO2 Emission Factor 2
(grams/idle-minute)
CH4 Emission Factor 2
(grams/idle-minute)
N2O Emission Factor 2
(grams/idle-minute)
HHDT Diesel 100% 8.84E+01 1.83E-03 0.00E+00

8.84E+01 1.83E-03 0.00E+00
Notes:

Abbreviations:CH4 - methane
CO2 - carbon dioxideEMFAC - EMission FACtors modelHHDT - Heavy Heavy-Duty TruckN2O - nitrous oxide SC - South Coast
Weighted Average Emission Factor 3
1 Concrete trucks are conservatively assumed to be diesel-fueled HHDT. 2 Idling emission factors were obtained from the default EMFAC2021 project-level output for Orange (SC) sub-area in calendar year 2027.
3 Weighted average emission factors for concrete trucks are calculated as the sumproduct of the Project-specific fleet mix and the emission factors for the individual vehicle class/fuel categories within that fleet mix.

DRAFT
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Table B-2. Greenhouse Gas Emissions from Concrete Trucks Idling and On-Road Travel During Project Construction Foothill Ranch Costco Project Lake Forest, California
Concrete Truck
Activity
Number of Days of
Concrete Truck Activity 1
(days)
Daily Trips 1
(round trips/day)
Annual Trips
(round trips/year)
Idle
Duration 1
(minutes/ round trip)
CO2
Emissions
(MT/year)
CH4
Emissions
(MT/year)
N2O
Emissions
(MT/year)
CO2e
Emissions
(MT/year)
Idling 2 102 4 419 60 2.2 4.6E-05 0 2.2
On-Road Travel 3 102 4 419 - 13 1.1E-03 0.0022 14
16 1.2E-03 0.0022 16
Notes:

Abbreviations:CalEEMod® - California Emissions Estimator Model CH4 - methane
CO2 - carbon dioxide
CO2e - carbon dioxide equivalentsIPCC - Intergovernmental Panel on Climate ChangeMT - metric tonsN2O - nitrous oxide Total Emissions
1 Based on Project-specific information.2 Idling emissions were estimated as a product of the emission factors from Table B-1, the idle duration per round trip, and the number of round trips per year.3 Obtained from the CalEEMod® model run for construction in Appendix A-1.

1311

APPENDIX C

SUPPORTING EMISSION CALCULATIONS FOR PROJECT OPERATION
DRAFT Foothill Ranch Costco Project
Greenhouse Gas Emissions Technical Report
Lake Forest, California
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List of Tables
Table C-1:

Table C-2:

Table C-3:

Table C-4:

Table C-5:

Operational Mobile Source Fleet Mixes
Operational Delivery Truck GHG Emission Factors
Operational GHG Emission Factors for Warehouse Delivery Truck Transport Refrigeration Units
Greenhouse Gas Emission Estimates for Transport Refrigeration Units Operational Emergency Generator GHG Emission Factors
DRAFT Foothill Ranch Costco Project
Greenhouse Gas Emissions Technical Report
Lake Forest, California
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Table C-1. Operational Mobile Source Fleet Mixes
Costco Foothill Ranch
Lake Forest, California
Gasoline 41,402,174 43.67% --
Plug-in Hybrid 1,693,689 1.79% --
Electricity 4,089,427 4.31% --
Diesel 72,324 0.08% --
Gasoline 3,351,769 3.98% --
Plug-in Hybrid 17,553 0.02% --
Electricity 21,261 0.03% --
Diesel 181 0.00% --
Gasoline 22,020,145 23.13% --
Plug-in Hybrid 311,544 0.33% --
Electricity 224,425 0.24% --
Diesel 88,904 0.09% --
Gasoline 12,751,503 13.98% --
Plug-in Hybrid 186,464 0.20% --
Electricity 237,228 0.26% --
Diesel 174,319 0.19% --
Gasoline 1,647,637 1.69% --
Diesel 995,052 1.02% --
Electricity 91,019 0.09% --
Gasoline 244,223 0.26% --
Diesel 433,595 0.46% --
Electricity 22,491 0.02% --
Gasoline 343,883 0.35% --
Diesel 1,162,783 1.17% --
Electricity 35,495 0.04% --
Natural Gas 13,849 0.01% --
Gasoline -- -- --
Diesel 1,309,094 -- 100%
Electricity -- -- --
Natural Gas -- -- --
Gasoline -- -- --
Diesel -- -- --
Electricity -- -- --
Natural Gas -- -- --
Gasoline -- -- --
Diesel -- -- --
Electricity -- -- --
Natural Gas -- -- --
MCY Gasoline 2.2% 2.2% 334,154 2.24% --
Gasoline -- -- --
Diesel -- -- --
Electricity -- -- --
Natural Gas -- -- --
Gasoline 54,533 0.24% --
Diesel 29,338 0.13% --
Abbreviations:

CalEEMod® - CALifornia Emissions Estimator MODel MDV - medium-duty vehicle EMFAC - EMission FACtors model MH - motor homes
HHDT - Heavy heavy-duty truck MHDT - medium heavy-duty trucks LDA - light duty automobiles OBUS - other buses
LDT - light-duty trucks SBUS - school buses
LHDT - light heavy-duty trucks UBUS - urban buses
MCY - motorcycles VMT - vehicle miles traveled
Vehicle
Category Fuel Type
CalEEMod®
Default Fleet
Mix1
Fleet Mix for
Vehicles
Visiting the
Warehouse2

EMFAC VMT
Output3
(miles/day)
Customer and
Employee Vehicles4
LDA 49.5% 49.8%
LDT1 4.0% 4.0%
LDT2 23.6% 23.8%
MHDT 1.6% 1.6%
MDV 14.5% 14.6%
LHDT1 2.8% 2.8%
Delivery Truck
Fleet Mix5
UBUS 0.04% --
SBUS 0.1% --
HHDT 0.6% --
OBUS 0.1% --
LHDT2 0.7% 0.7%
MH 0.4% 0.4%
Notes:
1 CalEEMod® default for Orange County, calendar year 2027. 2 Estimated using the CalEEMod® default fleet mix for Orange County. EMFAC vehicle classes that represent vehicles visiting the warehouse include LDA, LDT1, LDT2, MDV, LHDT1, LHDT2, MHDT, MCY, and MH. 3 Default EMFAC2021 output for the Orange County subarea in calendar year 2027. 4 The Project-specific fleet mix for customer and employee vehicles is estimated by apportioning the fleet mix for vehicles visiting the warehouse into the Project-specific fuel types (gasoline, plug-in hybrid, electricity, diesel) within each EMFAC vehicle class for vehicles visiting the warehouse (LDA, LDT1, LDT2, MDV, LHDT1, LHDT2, MHDT, MCY, and MH) using the default EMFAC VMT output for those fuel types.
5 The EMFAC vehicle class that represents delivery trucks is HHDT.

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Table C-2. Operational Delivery Truck GHG Emission Factors Costco Foothill RanchLake Forest, California
HFC Emission Factor2
RUNEX
(g/mi)
IDLEX
(g/trip)
STREX
(g/trip)
RUNEX
(g/mi)
IDLEX
(g/trip)
STREX
(g/trip)
RUNEX
(g/mi)
IDLEX
(g/trip)
STREX
(g/trip)
RUNEX
(g/mi)
Annual 1.54E+03 7.26E+02 0.00E+00 5.91E-04 1.49E-02 0.00E+00 2.43E-01 1.14E-01 0.00E+00 8.76E-04 Summer 1.54E+03 7.17E+02 0.00E+00 5.91E-04 1.58E-02 0.00E+00 2.43E-01 1.13E-01 0.00E+00 2.03E-03 Winter 1.54E+03 7.37E+02 0.00E+00 5.91E-04 1.37E-02 0.00E+00 2.43E-01 1.16E-01 0.00E+00 5.26E-05 Notes:

Abbreviations:CalEEMod® - California Emissions Estimator Model HHDT - Heavy Heavy-Duty Truck CH4 - methane IDLEX - idle exhaust
CO2 - carbon dioxide mi - mile
EMFAC - EMission FACtors model N2O - nitrous oxide
g - gram RUNEX - running exhaustGHG - greenhouse gas STREX - starting exhaustHFC - hydrofluorocarbon EMFAC
Vehicle
Class
Fuel
Type Season
1 Emission factors for Diesel HHDTs were obtained from the default EMFAC2021 output for Orange County - South Coast calendar year 2027. 2 Based on CalEEMod® defaults.

CO2 Emission Factors1 CH4 Emission Factors1 N2O Emission Factors1 HHDT Diesel

1315
Table C-3. Operational GHG Emission Factors for Warehouse Delivery Truck Transport Refrigeration Units Foothill Ranch Costco Project
Lake Forest, California
Transport Refrigeration Unit (TRU) Category Fuel Type
Total Statewide Activity 1
(hr/year)
Fuel Consumption 1
(gal/hr)
CO2 Emission Factor 1
(lbs/hr)
CH4 Emission Factor 2
(lbs/hr)
N2O Emission Factor
2 (lbs/hr)
Transport Refrigeration Unit - Instate Trailer Diesel 2,055,583 0.71 16 6.40E-04 1.25E-04 Transport Refrigeration Unit - Out-Of-State Trailer Diesel 1,186,175 0.68 15 6.14E-04 1.20E-04 16 6.30E-04 1.23E-04
Notes:
1 Total statewide activity, fuel consumption, and exhaust CO2 emission factors for TRUs were obtained from OFFROAD2021 emissions output for Orange (SC) sub-area calendar year 2027. 2 CH₄ and N₂O, emission factors were estimated based on fuel consumption obtained from OFFROAD2021 and USEPA emission factors in grams per gallon for stationary combustion of Distillate Oil No. 2.

USEPA GHG Emission Factors4
for Stationary Combustion of Distillate Oil No. 2:

CH4 Emission Factor 0.41 g/gal
N2O Emission Factor 0.08 g/gal
Abbreviations:

CH4 - methane hr - hour
CO2 - Carbon Dioxide equivalents lb - pound
g - gram N2O - nitrous oxide
gal - gallon SC - South Coast
GHG - greenhouse gas USEPA - United States Environmental Protection Agency Weighted Average Emission Factor 3
3 The activity weighted average emission factors for TRUs servicing the proposed Project were calculated using the emission factors and total statewide activity for each individual TRU category. 4 Obtained from USEPA Emission Factors for Greenhouse Gas Inventories. Available at:
https://www.epa.gov/system/files/documents/2025-01/ghg-emission-factors-hub-2025.pdf. Accessed: July 2025.

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Table C-4. Greenhouse Gas Emission Estimates for Transport Refrigeration Units Foothill Ranch Costco ProjectLake Forest, California
Mobile Source Activity
Annual TRU
Operational
Duration 1
(min/yr)
CO2
Emissions 2
(MT/yr)
CH4
Emissions 2
(MT/yr)
N2O
Emissions 2
(MT/yr)
Total GHG
Emissions 3,4
(MT CO2e/yr)
TRUs for Warehouse Delivery Trucks 248,716 29.4 0.001 0.000 29.5Notes:

Global Warming Potentials4: CO2 1
CH4 28
N2O 298
TRU Trip Information:

On-Site Operational Time During Truck Idling 5,6 15 minutes/round trip per TRU On-Site Truck Travel Distance 7 0.7 miles/round trip
On-Site Average Truck Travel Speed 8 5 miles/hour
On-Site Operational Time During Truck Travel 9 8.8 minutes/round trip per TRU Off-Site Truck Travel Distance 7 73.3 miles/round trip
Off-Site Average Truck Travel Speed 8 30 miles/hour
Off-Site Operational Time During Truck Travel 9 147 minutes/round trip per TRU Total Operational Time 10 170.4 minutes/TRU
Daily Number of TRUs 11 4 TRUs/day
Annual Number of TRUs 11 1,460 TRUs/year
Abbreviations:

AR4 - Fourth Assessment ReportATCM - Airborne Toxic Control MeasureCARB - California Air Resources BoardCH4 - methane CO2 - carbon dioxide
CO2e - carbon dioxide equivalentGHG - greenhouse gasIPCC- Intergovernmental Panel on Climate Changemin - minuteMT - metric tonN2O - nitrous oxide TRU - transport refrigeration unitUSEPA - United States Environmental Protection Agencyyr - year 2 TRU emissions were estimated using emission factors from Table C-3 and the annual TRU operational duration.1 Annual TRU operational duration is estimated based on total operational time per TRU and the number of TRUs per year, as provided in the TRU Trip Information below.
3 Total GHG emissions are presented as CO2e, which include CO2, CH4, and N2O emissions, weighted by their respective 100-year global warming potentials (IPCC AR4 Assessment). This aligns with the default used within CalEEMod. 9 The on-site and off-site TRU operational time during warehouse delivery truck travel was calculated by dividing the on-site and off-site truck travel distances by their corresponding average truck travel speeds, respectively. 10 The total operational time per TRU includes the operational time per round trip during on-site and off-site truck travel and on-site truck idling.11 The number of TRUs per day is based on Project-specific information. The total number of TRU uses per year was estimated by multiplying the daily number of TRUs by 365 operational days per year.
4 Obtained from USEPA Emission Factors for Greenhouse Gas Inventories. Available at:
https://www.epa.gov/system/files/documents/2025-01/ghg-emission-factors-hub-2025.pdf. Accessed: August 2025. 5 The idle duration per round trip is assumed to be 15 minutes (maximum 5 minutes at project site entry, maximum 5 minutes at loading dock, and maximum 5 minutes at project site exit), consistent with the CARB Air Toxic Control Measure to Limit Diesel-Fueled Commercial Motor Vehicle Idling. Available at https://ww2.arb.ca.gov/our-work/programs/atcm-to-limit-vehicle-idling/about. Accessed: August 2025. 6 The on-site TRU operational time during truck idling is assumed to be 15 minutes as described in footnote 5. TRUs will not idle for more than 5 minutes at the dock while unloading goods at the warehouse. 7 The on-site warehouse delivery truck travel distance was estimated based on the proposed Project site layout. The off-site warehouse delivery truck travel distance was calculated by subtracting the on-site travel distance from the total trip length for the warehouse delivery truck. 8 The on-site and off-site average truck travel speed are consistent with CARB's assumptions in Appendix I of the Proposed Amendments to the ATCM Measure for In-Use Diesel-Fueled TRU and TRU Generator Sets, and Facilities Where TRUs Operate. Available at: https://ww2.arb.ca.gov/sites/default/files/barcu/board/rulemaking/tru2021/appi.pdf. Accessed: August 2025.

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Table C-5. Emergency Generator GHG Emission Factors
Costco Foothill Ranch
Lake Forest, California
Equipment Type
CO2
1 (g/bhp-hr)
CH4
1 (g/bhp-hr)
N2O2,3
(g/bhp-hr)
Emergency Generator - CNG (0-500 HP) 349 0.73 7.00E-04
Constants:

Conversion factor3 3.1752 g/hp-hr per lb/MMBtu
Notes:
1 Based on CalEEMod® defaults.
2 In the absence of a CalEEMod® default, the N2O emission factor for natural gas fuel was referenced from the USEPA Emission Factors for Greenhouse Gas Inventories. Available at:
https://www.epa.gov/system/files/documents/2025-01/ghg-emission-factors-hub-2025.pdf. Accessed:

September 2025.
3 The conversion from the source emission factor in lb/MMBtu to an emission factor in g/bhp-hr for a natural gas emergency generator is referenced from CalEEMod® Appendix C. Available at:
https://caleemod.com/documents/user-guide/04_Appendix%20C.pdf. Accessed: September 2025.

Abbreviations:
bhp-hr - brake horsepower- hour
CalEEMod® - California Emissions Estimator Model
CH4 - methane
CNG - compressed natural gas
CO2 - carbon dioxide
g - gram
GHG - greenhouse gases
HP - horsepower
hp-hr - horsepower-hour
lb - pound
MMBtu - million British thermal unit
N2O - nitrous oxide
USEPA - United States Environmental Protection Agency

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APPENDIX D

PROJECT ANALYSIS AGAINST RELEVANT PLANS
DRAFT Foothill Ranch Costco Project
Greenhouse Gas Emissions Technical Report
Lake Forest, California
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List of Tables
Table D-1: CARB’s 2022 Scoping Plan Update - Project Analysis Table D-2: Connect SoCal 2024 (Regional Transportation Plan/Sustainable Communities Strategy) - Project Analysis
Table D-3: Lake Forest General Plan - Project Analysis
DRAFT Foothill Ranch Costco Project
Greenhouse Gas Emissions Technical Report
Lake Forest, California
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Table D-1. CARB’s 2022 Scoping Plan Update - Project Analysis Costco Foothill Ranch
Lake Forest, California
DRAFT
Priority Areas Priority GHG Reduction Strategies Does it Conflict? Convert local government fleets to ZEVs and provide EV charging at public sites
Create a jurisdiction-specific ZEV ecosystem to support deployment of ZEVs statewide (such as building standards that exceed state building codes, permit streamlining, infrastructure siting, consumer education, preferential parking policies, and ZEV readiness plans) Reduce or eliminate minimum parking standards
Implement Complete Streets policies and investments, consistent with general plan circulation element requirements
Increase access to public transit by increasing density of development near transit, improving transit service by increasing service frequency, creating bus priority lanes, reducing or eliminating fares, microtransit, etc.

Increase public access to clean mobility options by planning for and investing in electric shuttles, bike share, car share, and walking Implement parking pricing or transportation demand management pricing strategies
Amend zoning or development codes to enable mixed-use, walkable, transit-oriented, and compact infill development (such as increasing the allowable density of a neighborhood)
Preserve natural and working lands by implementing land use policies that guide development toward infill areas and do not convert “greenfield” land to urban uses (e.g., green belts, strategic conservation easements)
Does Not Conflict. Although this goal is not the responsibility of an individual commercial development project, according to the Project's Traffic Assessment, the Project will result in a net negative VMT impact, therefore supporting the VMT reduction priority area of the Scoping Plan. Furthermore, the Project is located on parcels that are zoned for mixed use in a region that is adjacent to existing infrastructure and development. The Project is expected to serve the existing population of the area by providing more convenient access to Costco services. The Project will be located in a central location and will allow customers to have multiple needs served in one trip, including but not limited to: eye exams, purchase of household goods and groceries, and tire service.

Transportation
Electrification
VMT Reduction
Does Not Conflict. Although this goal is not the responsibility of an individual commercial development project, the Project will include 12 DCFC EV stations (including 2 accessible stalls), and one level 2 charger which will provide Costco members with convenient EV charging at a lower cost.

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Table D-1. CARB’s 2022 Scoping Plan Update - Project Analysis Costco Foothill Ranch
Lake Forest, California
DRAFT
Priority Areas Priority GHG Reduction Strategies Does it Conflict? Adopt all-electric new construction reach codes for residential and commercial uses
Adopt policies and incentive programs to implement energy efficiency retrofits for existing buildings, such as weatherization, lighting upgrades, and replacing energy-intensive appliances and equipment with more efficient systems (such as Energy Star-rated equipment and equipment controllers)
Adopt policies and incentive programs to electrify all appliances and equipment in existing buildings such as appliance rebates, existing building reach codes, or time of sale electrification ordinances Facilitate deployment of renewable energy production and distribution and energy storage on privately owned land uses (e.g., permit streamlining, information sharing)
Deploy renewable energy production and energy storage directly in new public projects and on existing public facilities (e.g., solar photovoltaic systems on rooftops of municipal buildings and on canopies in public parking lots, battery storage systems in municipal buildings)
Notes:

Abbreviations:

CARB - California Air Resources Board
DCFC - direct current fast charging
EV - electric vehicle
GHG - greenhouse gas
VMT - vehicle miles traveled
ZEV - zero emission vehicle
1 Priority areas and GHG reduction strategies obtained from 2022 CARB Scoping Plan Update, Appendix D, Local Actions. Available at:
https://ww2.arb.ca.gov/sites/default/files/2022-11/2022-sp-appendix-d-local-actions.pdf. Accessed: September 2025.

Building
Decarbonization
Does Not Conflict. Although this goal is not the responsibility of an individual commercial development project, the Project would meet the CalGreen Building Standards Code in effect at the time of building permit application, which would include a number of energy saving requirements. Additionally, the Project includes a number of energy saving requirements, which would lead to GHG savings as well, which are outlined in Section 5.2.1 of the GHG Technical Report. Finally, the Project would include solar panels which would provide renewable energy to the Project and further reduce the GHG emissions associated with the building energy.

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Table D-2. Connect SoCal 2024 (Regional Transportation Plan/Sustainable Communities Strategy) - Project Analysis Costco Foothill Ranch
Lake Forest, California
DRAFT
Regional Planning Policy Area1 Policy Number1 Regional Planning Policy1 Does it Conflict? 3 Pursue the development of Complete Streets that comprise a safe, multi modal network with flexible use of public rights-of-way for people of all ages and abilities using a variety of modes (e.g., people walking, biking, rolling, driving, taking transit) 5 Facilitate the implementation of Complete Streets and curb space management strategies that accommodate and optimize new technologies, micromobility devices and first/last mile connections to transit and last-mile delivery 7 Encourage and support the implementation of projects, both physical and digital, that facilitate multimodal connectivity, prioritize transit and shared mobility, and result in improved mobility, accessibility and safety
9 Encourage and support the implementation of projects, both physical and digital, that facilitate multimodal connectivity, prioritize transit and shared mobility, and result in improved mobility, accessibility and safety
Transportation System
Management 12
Pursue efficient use of the transportation system using a set of operational improvement strategies that maintain the performance of the existing transportation system instead of adding roadway capacity, where possible 32 Promote the growth of origins and destinations, with a focus on future housing and population growth, in areas with existing and planned urban infrastructure that includes transit and utilities
Does Not Conflict. The proposed Project will be located in the Foothill Ranch Towne Center Shopping mall, which consists of existing urban infrastructure. The new warehouse will provide nearby residential areas with more convenient access to Costco services, including eye exams, purchases of household goods and groceries, and tire services. 33 Promote the growth of origins and destinations, in areas with a proclivity toward multi modal options like transit and active transportation, to reduce single occupant vehicle (SOV) dependency and vehicle miles traveled
34 Seek to realize scale economies or a critical mass of jobs and destinations in areas across the region that can support non-SOV options and shorter trip distances, combined trips and reduced vehicle miles traveled
15-Minute Communities 42
Promote 15-minute communities as places with a mix of complementary land uses and accessible mobility options that align with and support the diversity of places (or communities) across the region. These are communities where residents can either access their most basic, day-to-day needs within a 15-minute walk, bike ride or roll from their home or as places that result in fewer and shorter trips because of the proximity of complementary land uses
Does Not Conflict. The proposed Project is expected to serve the existing population of the area by providing more convenient access to Costco services. The Project will be located in a central location that is within a 15-minute walk of the nearest apartment complexes and will allow customers to have multiple needs served in one trip, including but not limited to: eye exams, purchase of household goods and groceries, and tire service. 48 Promote sustainable development and best practices that enhance resource conservation, reduce resource consumption and promote resilience 49 Support communities across the region to advance innovative sustainable development practices
50 Recognize and support the diversity of communities across the region by promoting local place-making, planning and development efforts that advance equity, mobility, resilience and sustainability
51 Reduce hazardous air pollutants and greenhouse gas emissions and improve air quality throughout the region through planning and implementation efforts 52 Support investments that reduce hazardous air pollutants and greenhouse gas emissions
53 Reduce the exposure and impacts of emissions and pollutants and promote local and regional efforts that improve air quality for vulnerable populations, including but not limited to Priority Equity Communities and the AB 617 Communities Does Not Conflict. The proposed Project is located near the Bake-Towne Centre bus stop and is within walking/biking/rolling distance of multiple apartment complexes, as well as other shops in the Foothill Ranch Towne Center Shopping mall, therefore promoting multiple transit options which would reduce peak-hour vehicle trips, and will create new employment opportunities in the region. Additionally, the Project would include bicycle parking as well which would further support the use of a variety of modes of transportation for employees commuting to work.

The proposed Project is expected to serve the existing population of the area by providing more convenient access to Costco services. The Project will be located in a central location and will allow customers to have multiple needs served in one trip, including but not limited to: eye exams, purchase of household goods and groceries, and tire service.

Does Not Conflict. Although this policy is not applicable to an individual project, the Greenhouse Gas Technical Report demonstrates less than significant impacts, thus, the Project will not conflict with the implementation GHG reduction plans. The Project includes sustainability design elements, as listed in Section 5.2.1.

Environment: Create a healthy region for the people of today and tomorrow Sustainable Development
Air Quality
Does Not Conflict. The proposed Project will reduce energy consumption by incorporating sustainable design features and systems with enhanced energy efficiencies meeting State and federal code requirements. The Project's proposed architectural design fits within the Development Guidelines and incorporates sustainable, recyclable, durable and low maintenance materials and design elements. Please see Section 5.2.1 of the GHG Technical Report for a full list of the energy-saving sustainability design features of the proposed Project.

Mobility: Build and maintain an integrated multimodal transportation network Complete Streets
Transit and Multimodal
Integration
Priority Development Areas
Communities: Develop, connect and sustain livable and thriving communities Does Not Conflict. The proposed Project will be located nearing existing residential areas, will be located near a bus stop, and will include bicycle parking. Therefore, the Project would provide retail and jobs near a housing-rich area served by the Orange County Transportation Authority.

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Table D-2. Connect SoCal 2024 (Regional Transportation Plan/Sustainable Communities Strategy) - Project Analysis Costco Foothill Ranch
Lake Forest, California
DRAFT
Regional Planning Policy Area1 Policy Number1 Regional Planning Policy1 Does it Conflict? 54 Accelerate the deployment of a zero-emission transportation system and use near-zeroemission technology to offer short-term benefits where zero-emissions solutions are not yet feasible or commercially viable
55 Promote equitable use of and access to clean transportation technologies so that all may benefit from them
58 Prioritize the climate mitigation, adaptation, resilience and economic benefits of natural and agricultural lands in the region
61 Encourage the protection and restoration of natural habitat and wildlife corridors 62 Encourage the conservation and viability of agricultural lands to protect the regional and local food supply and ensure the sustainability of local agriculture as a vital part of the region’s economy
65 Support local and regional climate and hazard planning and implementation efforts for transportation, land use, and other factors
Does Not Conflict. The proposed Project will incorporate storm water management plans to maintain quality control and storm water discharge rates. The Project will also enhance the area with a warehouse whose architecture is designed to be responsive to the City of Lake Forest's Community goals. According to the Project's Traffic Analysis, the Project will result in a net negative VMT impact. Lastly, the proposed Project includes a number of sustainability design element, which are described in detail in Section 5.2.1 of the GHG Technical Report.
67 Promote sustainable water use planning, practices and storage that improve regional water security and resilience in a drier environment
Does Not Conflict. The proposed Project's irrigation system will include the use of deep root watering bubblers for parking lot trees to minimize usage and ensure that water goes directly to the intended planting areas. The Project will include use of native species vegetation and drip irrigation systems to reduce potable water consumption, high-efficiency restroom fixtures for greater water savings, and storm water management plans to maintain quality control and storm water discharge waters. 70 Prioritize community and environmental justice concerns, together with economic needs, and support workforce development opportunities, particularly around deployment of zero-emission and clean technologies and their supporting infrastructure Does Not Conflict. The proposed Project will introduce a new Costco warehouse that serves the local community with goods and services from both nationally known businesses and regional and local businesses. It will enable patrons to travel shorter distances to access eye exams, purchase of household goods and groceries, and tire services, therefore reducing emissions from vehicle travel. Furthermore, the proposed Project will create new jobs in the region that are accessible via transit. 71 Explore and advance the transition toward zero-emission and clean technologies and other transformative technologies, where viable
Does Not Conflict. All Costco delivery trucks will be equipped with an engine idle shut off timer to reduce idling emissions.

Additionally, the Project will include 12 DCFC EV charging stations (including two accessible stalls), and one level 2 charger which will provide Costco members with convenient EV charging at a lower cost. 73 Ensure continued, significant investment in a safe, secure, clean and efficient transportation system—including both highways and rail—to support the intermodal movement of goods across the region
Does Not Conflict. The proposed Project is strategically located to minimize miles traveled for delivery.

Notes:

Abbreviations:

CalGreen - California Green Building Standards Code
DCFC - Direct Current Fast Charging
EV - Electric Vehicle
GHG - greenhouse gas
RTP/SCS - Regional Transportation Plan/Sustainable Communities Strategy SoCal - Southern California
VMT - vehicle miles traveled
Climate Resilience
Economy: Support a sustainable, efficient and productive regional economic environment that provides opportunities for all people in the region Goods Movement
1 SCAG. A Plan For A Brighter Future. Available at: https://scag.ca.gov/connect-socal. Accessed: September 2025.

Does Not Conflict. The proposed Project will be an infill development with construction occurring in a previously occupied commercial land parcel. The Project will not be constructed over any natural and agricultural lands or natural habitat and wildlife corridors.

Clean Transportation
Natural and Agricultural Lands
Preservation
Does Not Conflict. Although this policy is not applicable to an individual project, the Project will include 12 DCFC EV charging stations (including two accessible stalls), and one level 2 charger.

Environment: Create a healthy region for the people of today and tomorrow (Continued)

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Table D-3. Lake Forest General Plan - Project Analysis
Costco Foothill Ranch
Lake Forest, California
DRAFT
# Policy Does it Conflict?
RR-4.1
Regional Standards. Coordinate planning efforts with the South Coast Air Quality Management District (SCAQMD), Southern California Association of Governments (SCAG), and the California Air Resource Board (CARB) to meet local and regional air quality standards and ensure attainment of established goals.

Not Applicable. This policy addresses an air quality issue, and therefore is not applicable to a GHG assessment. However, the Project references the SCAQMD draft screening level (3,000 MT CO2e) as the GHG significance threshold for the Project. As noted in Section 5.1 of the GHG Technical Report, the Project will have a less than significant impact when compared to this SCAQMD screening level.

RR-4.2 Land Use Planning. Utilize land-use planning techniques to reduce traffic congestion and promote alternative modes of transportation for the community.

RR-4.3 Development. Encourage and incentivize the development of mixed-use residential opportunities and live-work environments within the City to lessen the impacts of traffic congestion on local air quality.

RR-4.4 Active Transportation. Improve active transportation options within the City by connecting local bikeways and trails to City bus stops and public transportation centers.

RR-4.5 Public Transit. Coordinate with the OCTA and actively pursue the improvement and expansion of public transit for Lake Forest residents.

RR-4.6 Sensitive Receptors. Insulate sensitive receptors from areas of heightened air quality pollution, including highways, by utilizing land use planning to buffer and protect residential areas. Not Applicable. This policy addresses an air quality issue, and therefore is not applicable to a GHG assessment.

RR-4.7 Mitigation. Require the implementation of relevant mitigation measures for all future development upon identification of potential air quality impacts.

Not Applicable. This policy addresses an air quality issue, and therefore is not applicable to a GHG assessment. However, the Project is less than significant for GHG as discussed in Section 5 of the GHG Technical Report and therefore there is no GHG significant impact.

Local Reduction Targets. The City of Lake Forest establishes the following per capita GHG reduction targets, in order to meet the requirements established by the state under AB 32 and SB 32, consistent with the CARB’s 2017 Scoping Plan:
• 3.99 MT CO2e per capita by 2030
• 2.66 MT CO2e per capita by 2040; and
• 1.33 MT CO2e per capita by 2050
RR-4.9 GHG Reduction. Consider and adopt new policies and programs that will help to provide energy efficient alternatives to fossil fuel use and reduce consumption in order to reduce greenhouse gas emissions.

Does Not Conflict. This is a policy that the City would implement rather than an individual project. However, the Project would include a number of energy saving requirements, which would lead to GHG reduction as well, which are outlined in Section 5.2.1 of the GHG Technical Report. Finally, the Project would include solar panels which would provide renewable energy to the Project and further reduce the GHG emissions associated with the building energy.

RR-4.10 Carbon Reduction. Expand the number of parks and trees in Lake Forest to provide a larger carbon sink or area containing natural sources that retain more carbon than what those sources emit.

Does Not Conflict. This is a policy that the City would implement rather than an individual project. The Project will include landscaped area as part of the design.

RR-4.11
Public Engagement. Promote regional air quality programs in order to inform the public on regional air quality concerns and encourage the engagement of all Lake Forest residents in future planning decisions related to air quality.

Not Applicable. This policy addresses an air quality issue, and therefore is not applicable to a GHG assessment.

RR-4 Policies
Does Not Conflict. This is a City-wide target and it is not applicable to an individual project. The significance thresholds are discussed in Section 3 of the GHG Technical Report and the Project is less than significant.

Does Not Conflict. The Project is located near the Bake-Towne Centre bus stop and is within walking/biking distance of multiple apartment complexes, as well as other shops in the Foothill Ranch Towne Center Shopping mall, therefore promoting alternative modes of transportation which would reduce peak-hour vehicle trips. The Project will be located in a central location that is within a 15-minute walk of the nearest apartment complexes and will allow customers to have multiple needs served in one trip, including but not limited to: eye exams, purchase of household goods and groceries, and tire service.

The Project would provide retail and jobs near a housing-rich area served by the Orange County Transportation Authority.

RR-4.8

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Table D-3. Lake Forest General Plan - Project Analysis
Costco Foothill Ranch
Lake Forest, California
DRAFT
RR-4 Policies
# Action Does it Conflict?
RR-4a
Review all new industrial and commercial development projects for potential air quality impacts to residences and other sensitive receptors. Ensure that mitigation measures and best management practices are implemented to reduce significant emissions of criteria pollutants.

Review development, infrastructure, and planning projects for consistency with SCAQMD requirements during the CEQA review process. Require project applicants to prepare air quality analyses to address SCAQMD and General Plan requirements, which include analysis and identification of:

1. Air pollutant emissions associated with the project during construction, project operation, and cumulative conditions.

2. Potential exposure of sensitive receptors to toxic air contaminants.

3. Significant air quality impacts associated with the project for construction, project operation, and cumulative conditions.

4. Mitigation measures to reduce significant impacts to less than significant or the maximum extent feasible where impacts cannot be mitigated to less than significant.

RR-4c Work with Orange County and the South Coast Air Quality Management District to implement programs aimed at improving regional air quality. Not Applicable. This action addresses an air quality issue, and therefore is not applicable to a GHG assessment.

RR-4d
Continue to review development projects to ensure that all new public and private development complies with the California Code of Regulations (CCR), Title 24 standards as well as the energy efficiency standards established by the Lake Forest Municipal Code.

Does Not Conflict. This is an action that the City would implement rather than an individual project, however the Project would meet the Title 24 in effect at the time of building permit application, which would include a number of energy saving requirements.

RR-4e
Monitor GHG emissions generated by the community over time for consistency with the established GHG reduction targets, and update the City’s community GHG Inventory every five years. In the event that the City determines that ongoing efforts to reduce GHG emissions are not on track to meet the City’s adopted GHG reduction targets, the City shall establish and adopt new and/or revised GHG reductions measures that will effectively meet the established GHG reduction targets.

Does Not Conflict. This is an action that the City would implement rather than an individual project, however the Project will not conflict with the City's ability to adopt new and/or revised GHG reductions measures.

RR-4f
Provide the necessary facilities and infrastructure to facilitate the use of City-owned low or zero emission vehicles such as electric vehicle charging facilities and conveniently located alternative fueling stations at key City facilities as operations necessitate and/or as funding becomes available.

Does Not Conflict. Although this policy is not applicable to an individual project, the Project will install 12 DCFC electric vehicle chargers (including 2 accessible stalls), and one level 2 charger.

RR-4g
Evaluate and consider multi-modal transportation benefits to all City employees, such as free or low-cost monthly transit passes. Encourage employer participation in similar programs. Encourage new transit/shuttle services and use.

Does Not Conflict. The Project plans to encourage employee commute trip reduction through a variety of strategies. The Project will provide rideshare information to employees, carpool and vanpool parking, and bicycle storage and locker rooms for employees who bike to work. This will provide incentives for employees to commute to work in alternative ways, which could lead to employee VMT reductions.

RR-4h Evaluate and consider the feasibility of allowing private bicycle rental companies to operate in Lake Forest.

RR-4i Encourage community car-sharing and carpooling.

RR-4j Support the establishment and expansion of a regional network of electric vehicle charging stations and encourage the expanded use of electric vehicles.

RR-4k
Establish and adopt standards and requirements for electric vehicle parking, including minimum requirements for the installation of electric vehicle charging stations in new multi-family residential and commercial, office, and light industrial development.

Not Applicable. These actions address air quality issues, and therefore are not applicable to a GHG assessment. However, the Project is less than significant for GHG, as discussed in Section 5 of the GHG Technical Report, which includes discussion of the Project inventory against the SCAQMD draft screening level (3,000 MT CO2e).

RR-4b
Does Not Conflict. This is an action that the City would implement rather than an individual project, however the Project would not conflict with the City's ability to implement this measure.

Does Not Conflict. The Project will include 12 DCFC electric vehicle chargers (including 2 accessible stalls), and one level 2 charger.

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Table D-3. Lake Forest General Plan - Project Analysis
Costco Foothill Ranch
Lake Forest, California
DRAFT
RR-4 Policies
# Action Does it Conflict?
RR-4l Periodically review and update the City’s Green Building Program to reflect best practices, such as encouraging the use of cement substitutes and recycled building materials for new construction.

RR-4m
Update the City’s Green Building Program to promote the reduction of urban heat islands through vegetation management and cool surfaces. Encourage multi-family residential and nonresidential development to increase the use of higher-albedo materials for surfaces including roofs, parking areas, driveways, roads, and sidewalks.

Encourage developments with parking lot areas to shade these areas with vegetation or solar panels when appropriate. Support various programs to plant and maintain trees, which can also contribute to a reduction of urban heat islands.

Future development projects implemented under the General Plan will be required to demonstrate consistency with SCAQMD construction emission thresholds. Where emissions from individual projects exceed SCAQMD thresholds, the following actions shall be incorporated as necessary to minimize impacts. These measures do not exclude the use of other, equally effective mitigation measures.
• Require all off-road diesel equipment greater than 50 horsepower (hp) used for this Project to meet USEPA Tier 4 final off-road emission standards or equivalent. Such equipment shall be outfitted with Best Available Control Technology (BACT) devices
including a California Air Resources Board Certified Level 3 Diesel Particulate Filter (DPF) or equivalent. This DPF will reduce diesel particulate matter and NOx emissions during construction activities • Require a minimum of 50 percent of construction debris be diverted for recycling. • Require building materials to contain a minimum 10 percent recycled content. • Require materials such as paints, primers, sealants, coatings, and glues to have a low volatile organic compound concentration compared to conventional products. If low VOC materials are not available, architectural coating phasing should be extended sufficiently to reduce the daily emissions of VOCs.

RR-4n
Does Not Conflict. These actions address a mix of air quality and GHG issues. The Project is less than significant for GHG, as discussed in Section 5 of the GHG Technical Report, which includes discussion of the Project inventory compared to the SCAQMD draft screening level (3,000 MT CO2e). Out of the four examples provided, the second and third bullets are the most relevant to GHG, and the Project will include design features that touch on these items. See below for a summary of the relevant design features of the Project:
• Construction waste is recycled whenever possible.
• Main Building structure is a pre-engineered system that uses 100% recycled steel materials and is designed to minimize the amount of material utilized.
• Roof material is recycled standing seam metal panel, designed to maximum efficiency for spanning the structure.

Note, the Project includes additional sustainability design elements, which are listed in Section 5.2.1 of the GHG Technical Report.

Does Not Conflict. This is an action that the City would implement rather than an individual project. For new buildings, Costco uses pre-manufactured metal wall panels with insulation carry a higher R-Value and greater solar reflectivity to help conserve energy. Costco also uses a reflective cool roof material to produce lower heat absorption and thereby lowering energy requirements during the hot summer months. This roofing material meets the requirements for the EPA’s Energy Star energy efficiency program. Additionally, the Project will include landscaped area and solar panels, which will shade the parking lot areas as well.

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Table D-3. Lake Forest General Plan - Project Analysis
Costco Foothill Ranch
Lake Forest, California
DRAFT
RR-4 Policies
# Action Does it Conflict?
Future development projects implemented under the General Plan will be required to demonstrate consistency with SCAQMD’s operational emission thresholds. For projects where operational emissions exceed regulatory thresholds, the following measures may be used to reduce impacts. Note the following measures are not all inclusive and developers have the option to add or substitute measures that are equally or more appropriate for the scope of their project.
• Develop a project specific TDM program for residents and/or employees that provides opportunities for carpool/vanpools.
• Provide onsite solar/renewable energy in excess of regulatory requirements. • Require that owners/tenants of non-residential or multi-family residential developments use architectural coatings that are 10 grams per liter or less when repainting/repairing properties. • Require dripless irrigation and irrigation sensor units that prevent watering during rain storms. • Ensure all parking areas are wired for capability of future EV charging and include EV charging stations that exceed regulatory requirements.

Notes:

Abbreviations:

AB - Assembly Bill MT - metric ton
BACT - Best Available Control Technology NOx
- nitrogen oxide compounds (NO + NO2)
CalGreen - California Green Building Standards Code OCTA - Orange County Transportation Authority CARB - California Air Resources Board PM10 - particulate matter less than 10 microns in diameter CCR - California Code of Regulations PM2.5 - particulate matter less than 2.5 microns in diameter CEQA - California Environmental Quality Act RR - Recreation and Resources CO - carbon monoxide SB - Senate Bill
CO2e - carbon dioxide equivalent SCAG - Southern California Association of Governments DCFC - Direct Current Fast Charging SCAQMD - South Coast Air Quality Management District DPF - Diesel Particulate Filter SOX - sulfur oxides
EPA - Environmental Protection Agency TDM - transportation demand management EV - electric vehicle USEPA - United States Environmental Protection Agency GHG - greenhouse gas VMT - vehicle miles traveled
hp - horsepower VOC - volatile organic compound
RR-4o
Does Not Conflict. The Greenhouse Gas Technical Report demonstrates less than significant impacts, and therefore additional measures will not be required to be implemented. The Project is less than significant for GHG, as discussed in Section 5 of the GHG Technial Report, which includes discussion of the Project inventory compared to the SCAQMD draft screening level (3,000 MT CO2e). However, the Project will include a number of the suggested measures, including the following. Please note that only the GHG-related measures are addressed below.
• The Project plans to encourage employee commute trip reduction through a variety of strategies. The Project will provide rideshare information to employees, carpool and vanpool parking, and bicycle storage and locker rooms for employees who bike to work. This will provide incentives for employees to commute to work in alternative ways, which could lead to employee VMT reductions.
• The Project will include on-site solar renewable energy generation. • The Project's irrigation system includes the use of deep root watering bubblers for parking lot trees to minimize usage and ensure that water goes directly to the intended planting areas. • The Project will include 12 DCFC electric vehicle chargers (including 12 accessible stalls), and one level 2 charger.

Note, the Project includes additional sustainability design elements, which are listed in Section 5.2.1 of the GHG Technical Report.
1 Policies and actions for Goal RR-4: Air Quality and Greenhouse Gas Emissions was referenced from the City of Lake Forest General Plan, adopted June 2020. Available at:
https://www.lakeforestca.gov/departments/community_development/planning/plans_and_standard_guidelines.php#undefined. Accessed: September 2025.

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Costco Wholesale Project
CEQA Guidelines 15183 | Environmental Compliance Checklist Appendix F
Appendix F – Hydrology Report

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Preliminary Hydrology & Hydraulics
Report
for
SDP 05-25-5800
Costco Foothill Ranch
26602 Town Center Drive,
Foothill Ranch, CA 92610
NOVEMBER 2025
PREPARED FOR:

Costco Wholesale
9 Corporate Park, Suite 230
Irvine, CA 92606
PREPARED BY:
1100 Town and Country Road, Suite 700
Orange, CA 92868
(714) 705-1364
Copyright © 2025 Kimley-Horn and Associates, Inc.

KHA Project # 094169109
This document, together with the concepts and designs presented herein, as an instrument of service, is intended only for the specific purpose and client for which it was prepared. Reuse of and improper reliance on this document without written authorization and adaptation by Kimley-Horn and Associates, Inc. shall be without liability to Kimley-Horn and Associates, Inc.

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2 Costco Foothill Ranch Preliminary Hydrology Report
November 2025
Contents
Introduction .................................................................................................................................4 Project Description......................................................................................................................4 Location ......................................................................................................................................4 Methodology ...............................................................................................................................5 Precipitation................................................................................................................................ 6 FEMA Mapping ........................................................................................................................... 6 Soil Types................................................................................................................................... 6 Groundwater............................................................................................................................... 6 Infiltration.................................................................................................................................... 6 Factor of Safety........................................................................................................................... 7 Pre-development Condition......................................................................................................... 7 Post-Development Condition....................................................................................................... 7 Stormwater Mitigation .................................................................................................................8 Hydraulic Analysis.......................................................................................................................8 Conclusion..................................................................................................................................8 Appendices
Appendix A - Rainfall Data ..........................................................................................................9 Appendix B - FIRM MAP...........................................................................................................10 Appendix C – Soils Information .................................................................................................11 Appendix D - Existing and Proposed Drainage Maps ................................................................12 Appendix E - Rational Method Analysis.....................................................................................13 Appendix F - Unit Hydrograph Analysis.....................................................................................14 Appendix G – Detention Basin Calculations ..............................................................................15 Appendix H – Hydraulic Calculations ........................................................................................16 Appendix I – Kleinfelder Drainage Report .................................................................................17 Item: 11
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3 Costco Foothill Ranch Preliminary Hydrology Report
November 2025
Tables
Table 1: Pre-Development Flows ................................................................................................7 Table 2: Post-Development Flows (Un-mitigated) .......................................................................7 Table 3: Proposed 100-year Final (Mitigated) Flows vs. Existing Flows ......................................8 Figures
Figure 1: Location Map ...............................................................................................................5 Item: 11
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4 Costco Foothill Ranch Preliminary Hydrology Report
November 2025

INTRODUCTION
Kimley-Horn and Associates has been retained to prepare a Preliminary Hydrology Report for the proposed Costco Foothill Ranch store in the City of Lake Forest, California. The purpose of this report is to demonstrate preliminary analysis of the hydrologic and hydraulic conditions associated with the development of the project site. To do so, the following is the scope of this report:
 Discuss the pre-development discharge patterns and points.  Discuss the post-development discharge patterns and points.  Determine the pre-development onsite flow rates for the 100-year event.  Determine the post-development un-mitigated flow rates for the 100-year event.  Determine required post-development onsite mitigation for the 100-year event to be less than or equal to the pre-development 100-year event.

Even though this report discusses stormwater, this report is not a Stormwater Pollution Prevention Plan (SWPPP), a Groundwater Study, a Geotechnical Report, nor a Water Quality Management Plan (WQMP).

Each of these separate reports discusses separate aspects of stormwater. Portions of the Geotechnical Report are utilized and referenced for the purpose of this report. Similarly, the requirements of the WQMP are considered for the stormwater mitigation and sizing of outlet structures for this project.

PROJECT DESCRIPTION
The existing developed area will be developed into the proposed Costco Foothill Ranch store. The project site is within the influence of the City of Lake Forest, within Northern Orange County. The project site encompasses Parcel 1 P.M. NO. 96-100 and P.M.B. 297/43-48. The APN for the project site is 612-093-

13. The project property encompasses approximately 15.93 acres. Only 90% of the site will be re-developed due to the north end of the property to be dedicated to the adjacent businesses.

The proposed project consists of the proposed Costco Warehouse building, with the associated parking lot and directly adjacent frontage improvements. The total building square footage is anticipated to be approximately 161,295 square feet. The associated improvements include, but are not limited to, onsite grading, domestic water service, sanitary sewer service, storm drain infrastructure, concrete and asphalt pavement, landscaping, and irrigation. The proposed building use will be commercial. Daily routine site activities will consist of customers entering the Costco Warehouse building and employees walking through the parking lot areas to retrieve shopping carts. Two trash compactors will be provided onsite. The site will include approximately 44,649 square feet of landscaping. The site is currently developed as 94% impervious and 6% pervious. Once the site is developed, the site will be 93% impervious and 7% pervious.

The proposed site will mostly drain south and be captured by onsite grate inlets, which then will be routed to be treated by EcoStream. From there the water will then be routed to a detention basin where overflow will be connected to the existing storm drain system.

LOCATION
The site is located northwest of the intersection of Towne Center Dr and Market (Private Road) in the City of Lake Forest, Orange County. The project site is bordered by the Private Road to the North, HWY 241 to the west, a developed town center to the south, and small businesses to the east.

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5 Costco Foothill Ranch Preliminary Hydrology Report
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FIGURE 1: LOCATION MAP

METHODOLOGY
The design criteria for the hydrologic calculations for this project have been conducted per requirements as outlined in the Orange County Hydrology Manual (October 1986).

Runoff calculations were performed using the Rational Method as utilized by the HydroWin Advanced Engineering Software, (AES). AES was used to estimate time of concentrations and 100-year peak flow rates generated from the pre- and post-development conditions. These Rational Method calculations are included in this report as Appendix E. Curve numbers were established from Figures C-3 and C-4 of the Hydrology Manual. Intensity values were obtained from the National Oceanic and Atmospheric Administration (NOAA). Loss rates were calculated using equations E.4 and E.5 of the Hydrology Manual.

Volume calculations were performed using the small unit hydrograph method through the AES software, and the results are included in Appendix F. This method calculates a unit hydrograph using time of concentration, maximum watershed loss rates, low lost fraction and an S-graph as specified in the Hydrology Manual. The time of concentration was determined from the Rational Method analysis in AES.

The maximum watershed loss rate was obtained directly from the unit hydrographs that were prepared using the methodology described in Section E of the Hydrology Manual in AES.

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6 Costco Foothill Ranch Preliminary Hydrology Report
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PRECIPITATION
According to NOAA Atlas 14, the following are the precipitation values that have been utilized for our study:
100-year storm 5-minute point rainfall (inches) = 0.44
100-year storm 30-minute point rainfall (inches) = 1.08 100-year storm 1-hour point rainfall (inches) = 1.52
100-year storm 3-hour point rainfall (inches) = 2.85
100-year storm 6-hour point rainfall (inches) = 4.10
100-year storm 24-hour point rainfall (inches) = 7.26
See Appendix A, for project location rainfall maps from NOAA Atlas 14.

FEMA MAPPING
The site is located in Zone X-unshaded per the Federal Emergency Management Administration (FEMA) Flood Insurance Rate Map (FIRM) panel 06059C0316J, dated December 3, 2009. Flood Zone X-unshaded is defined by FEMA to have minimal flood hazard. For reference, see Appendix B, FIRM Map.

SOIL TYPES
The type of soil and soil conditions are major factors affecting infiltration/detention and resultant storm water runoff. The Natural Resources Conservation Service (NRCS) has classified soil into one general hydrologic soil groups for comparing infiltration and runoff rates. Each group is based on properties that influence runoff, such as water infiltration rate, texture, natural discharge, and moisture condition. The runoff potential is based on the amount of runoff at the end of a long duration storm that occurs after wetting and swelling of the soil not protected by vegetation. Using the United States Department of Agriculture Natural Resources Conservation Service Web Soil Survey online tool and the Stormwater Facility Mapping online tool for Orange County, it was determined the hydrologic soil group classification is A. Soil group A is defined as soils having good infiltration rates (low runoff potential). These soils have a good rate of water transmission.

Based on the Percolation Test, from Kleinfelder, it was concluded that infiltration is deemed to be infeasible due to low percolation rates. Based on borings and percolation tests, fill soils were not encountered. The design infiltration rate in the soils closest to the location of the proposed underground infiltration system is

0.02 inches/hour, without a factor of safety. See Appendix B for the Web Soil Survey Report and Appendix C for the Geotechnical Reports.

GROUNDWATER
Per the Draft Geotechnical Investigation Report prepared by Kleinfelder, groundwater was not encountered during the maximum depth explored of approximately 49 ½ feet.

INFILTRATION
Kleinfelder performed four percolation tests in general accordance with the Orange County Technical Guidance for Water Quality Management Plans using shallow boring percolation test methods (falling head). Tests were performed at depths of approximately 3 and 10 feet borings. The infiltration rate was deemed infeasible due to low rates.

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FACTOR OF SAFETY
The factor of safety was determined based on Worksheet H, the Factor of Safety and Design Infiltration Rate and Worksheet from the Water Quality Management Plan. The combined safety factor is determined from the product of the Suitability Assessment Safety Factor (Factor A) and the Design Factor (Factor B).

The combined safety factor was determined to be 4.4 and then applied to the measured infiltration rate.

Infiltration was deemed unfeasible due to low rates. Factor of safety calculations have been provided for reference in Appendix C.

PRE-DEVELOPMENT CONDITION
The site is currently 100% developed. The existing site generally sheet flows in a southernly direction, where they are captured by on-site catch basins. The existing site consist of 4 drainage areas, DA-A, DAB, DA-C, and DA-D which encompasses the entire site. The entire site drains southernly. All runoff is captured into the existing underground storm drain system where it ultimately drains to Serrano Creek.

Table 1 shows the summary of the pre-development flows for the onsite drainage areas. See Appendix D for the Existing Drainage Map and Appendix E for the rational method calculations.

Table 1: Pre-Development Flows

POST-DEVELOPMENT CONDITION
The grading for the proposed site will maintain the natural flow pattern of the existing site to the maximum extent practicable. This analysis was done for the 2, 10, 100-year storm events. In the proposed conditions, the project site was split into DMA A and B leading to 1 underground detention system.

Drainage from this DMA will flow into an underground EcoStreams for treatment and then routed into a detention basin and sent to the existing onsite storm drain system.

Table 2: Post-Development Flows (Un-mitigated)
Drainage Area Drainage
Area (AC)
Time of
Concentration
(min)
Q2 (cfs) Q100 (cfs)
DA A 1.51 6.40 2.58 7.04
DA B 6.47 8.82 9.25 25.28
DA C 3.94 7.39 5.68 15.54
DA D 4.01 18.01 3.90 10.64
Total 15.93 - 21.41 58.50
Drainage Area Drainage Area
(AC)
Time of
Concentration (min) Q2 (cfs) Q100 (cfs)
A1 2.83 7.68 4.45 12.26
A2 1.65 5.78 2.76 7.61
A3 2.37 5.64 4.65 18.78
A4 4.48 8.44 7.15 20.47
A5 0.34 9.81 0.58 1.61
A6 1.30 5.10 2.54 6.99
A7 2.96 11.12 3.90 11.22
TOTAL 15.93 14.6 22.13 63.54
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8 Costco Foothill Ranch Preliminary Hydrology Report
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STORMWATER MITIGATION
For proposed onsite flows, stormwater mitigation is needed to ensure the proposed flows do not negatively impact the existing downstream drainage facilities. The underground detention system will serve to meet the water quality requirements and mitigate peak flow. To mitigate the increased flows an underground detention basin is proposed. The basin’s outlet structure is intended to restrict peak flows into the proposed conditions to level equal to or less than the existing flows.

The outlet structure consists of 24” orifice at the bottom of the system and is connected to the proposed detention system located towards the south of the site. The system was modeled in AutoCad Civil3D Hydrograph extension. Based on the basin routing analysis for the 2-, 10-, 100-year storm events, the highest routed (mitigated) onsite outflows from the underground detention system result in proposed flows that are less than the allowable flow rate for the project site. Water will exit out of the control structure through the outlet and connect to a proposed storm drain located offsite. Refer to Appendix G for AutoCad Civil3D hydrograph extension results showing mitigated flows.

Per the design of the Advanced Drainage Systems (ADS) MC-3500 with footprint 45.5’ x 22.9’ with 24” orifice which serves to detail peak flows prior to being discharged to existing storm drain system.

See below table and exhibits for more information along with Appendix G for calculations.

Table 3: Proposed 100-year Final (Mitigated) Flows vs. Allowable Flow

HYDRAULIC ANALYSIS
The calculated peak flows will be used to size the onsite pipes and inlets. Calculations will be provided during final engineering.

CONCLUSION
In conclusion, the following was covered in this report:
 The pre-development discharge patterns and points were discussed.  The post-development discharge patterns and points were discussed.  The pre-development flow rates up to the 100-year event were determined.  The post-development un-mitigated flow rates up the 100-year event were determined.  The post-development stormwater mitigation up to the 100-year event was analyzed.

As discussed in the report, the proposed developed discharges less stormwater than existing. Therefore, development is not expected to cause a negative impact to the downstream systems.

Drainage Area Drainage
Area
(AC)
Allowable
Q100 (cfs)
Mitigated
Q100 (cfs)
Volume
Provided
(cf)
A 15.93 58.50 5.04 7,903
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9 Costco Foothill Ranch Preliminary Hydrology Report
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Appendix A - Rainfall Data
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NOAA Atlas 14, Volume 6, Version 2
Location name: Foothill Ranch, California, USA*
Latitude: 33.6766°, Longitude: -117.669°
Elevation: 779 ft**
* source: ESRI Maps
** source: USGS

POINT PRECIPITATION FREQUENCY ESTIMATES
Sanja Perica, Sarah Dietz, Sarah Heim, Lillian Hiner, Kazungu Maitaria, Deborah Martin, Sandra Pavlovic, Ishani Roy, Carl Trypaluk, Dale Unruh, Fenglin Yan, Michael Yekta, Tan Zhao, Geoffrey Bonnin, Daniel Brewer, Li-Chuan Chen, Tye Parzybok, John Yarchoan NOAA, National Weather Service, Silver Spring, Maryland PF_tabular | PF_graphical | Maps_&_aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches) 1 Duration
Average recurrence interval (years)
1 2 5 10 25 50 100 200 500 1000
5-min 0.137
(0.115‑0.164)

0.177
(0.148‑0.213)

0.231
(0.193‑0.280)

0.277
(0.229‑0.337)

0.340
(0.272‑0.429)

0.390
(0.304‑0.504)

0.442
(0.336‑0.586)

0.496
(0.367‑0.679)

0.573
(0.405‑0.819)

0.635
(0.433‑0.941)
10-min 0.196
(0.164‑0.236)

0.254
(0.213‑0.306)

0.332
(0.277‑0.401)

0.396
(0.328‑0.483)

0.487
(0.389‑0.615)

0.558
(0.436‑0.722)

0.633
(0.482‑0.840)

0.712
(0.526‑0.973)

0.822
(0.581‑1.17)

0.910
(0.620‑1.35)
15-min 0.237
(0.199‑0.285)

0.307
(0.257‑0.370)

0.401
(0.335‑0.485)

0.479
(0.397‑0.585)

0.589
(0.471‑0.744)

0.675
(0.528‑0.873)

0.765
(0.583‑1.02)

0.861
(0.636‑1.18)

0.994
(0.703‑1.42)

1.10 (0.750‑1.63)
30-min 0.335
(0.281‑0.403)

0.434
(0.364‑0.524)

0.568
(0.474‑0.686)

0.679
(0.562‑0.828)

0.833
(0.666‑1.05)

0.956
(0.747‑1.24)

1.08 (0.825‑1.44)

1.22 (0.900‑1.66)

1.41 (0.995‑2.01)

1.56 (1.06‑2.31)
60-min 0.468
(0.393‑0.564)

0.607
(0.509‑0.732)

0.793
(0.663‑0.959)

0.949
(0.786‑1.16)

1.16 (0.931‑1.47)

1.34 (1.04‑1.73)

1.52 (1.15‑2.01)

1.70 (1.26‑2.33)

1.97 (1.39‑2.81)

2.18 (1.48‑3.23)
2-hr 0.685
(0.575‑0.824)

0.881
(0.739‑1.06)

1.15 (0.962‑1.39)

1.38 (1.14‑1.68)

1.71 (1.37‑2.16)

1.98 (1.54‑2.55)

2.26 (1.72‑3.00)

2.56 (1.90‑3.51)

3.00 (2.12‑4.29)

3.37 (2.29‑4.99)
3-hr 0.858
(0.720‑1.03)

1.10 (0.923‑1.33)

1.44 (1.20‑1.74)

1.73 (1.43‑2.11)

2.14 (1.71‑2.71)

2.49 (1.94‑3.21)

2.85 (2.17‑3.78)

3.25 (2.40‑4.44)

3.83 (2.70‑5.47)

4.31 (2.94‑6.38)
6-hr 1.23
(1.03‑1.48)

1.58 (1.32‑1.90)

2.07 (1.73‑2.50)

2.48 (2.06‑3.03)

3.08 (2.46‑3.90)

3.57 (2.79‑4.62)

4.10 (3.12‑5.44)

4.67 (3.45‑6.38)

5.49 (3.88‑7.85)

6.18 (4.21‑9.16)
12-hr 1.62
(1.36‑1.96)

2.11 (1.77‑2.54)

2.77 (2.31‑3.34)

3.32 (2.75‑4.05)

4.11 (3.28‑5.19)

4.74 (3.70‑6.12)

5.40 (4.11‑7.16)

6.10 (4.51‑8.34)

7.10 (5.02‑10.1)

7.90 (5.39‑11.7)
24-hr 2.15
(1.90‑2.48)

2.83 (2.50‑3.27)

3.74 (3.29‑4.33)

4.50 (3.93‑5.25)

5.56 (4.70‑6.70)

6.39 (5.30‑7.87)

7.26 (5.88‑9.15)

8.18 (6.44‑10.6)

9.45 (7.16‑12.7)

10.5 (7.67‑14.6)
2-day 2.61
(2.30‑3.01)

3.48 (3.07‑4.02)

4.65 (4.10‑5.39)

5.64 (4.92‑6.58)

7.01 (5.93‑8.46)

8.11 (6.72‑9.98)

9.25 (7.49‑11.7)

10.5 (8.24‑13.5)

12.2 (9.20‑16.4)

13.5 (9.90‑18.8)
3-day 2.80
(2.48‑3.24)

3.77 (3.33‑4.36)

5.09 (4.48‑5.89)

6.19 (5.41‑7.23)

7.75 (6.56‑9.35)

9.00 (7.46‑11.1)

10.3 (8.35‑13.0)

11.7 (9.22‑15.2)

13.7 (10.3‑18.4)

15.2 (11.2‑21.2)
4-day 3.02
(2.67‑3.49)

4.09 (3.61‑4.73)

5.54 (4.88‑6.42)

6.77 (5.92‑7.91)

8.51 (7.20‑10.3)

9.90 (8.21‑12.2)

11.4 (9.20‑14.3)

12.9 (10.2‑16.7)

15.1 (11.5‑20.4)

16.9 (12.4‑23.6)
7-day 3.47
(3.06‑4.00)

4.72 (4.16‑5.45)

6.43 (5.66‑7.45)

7.88 (6.88‑9.20)

9.94 (8.41‑12.0)

11.6 (9.61‑14.3)

13.3 (10.8‑16.8)

15.2 (12.0‑19.7)

17.9 (13.5‑24.1)

20.1 (14.7‑27.9)
10-day 3.76
(3.32‑4.34)

5.14 (4.54‑5.94)

7.03 (6.19‑8.14)

8.63 (7.54‑10.1)

10.9 (9.23‑13.2)

12.8 (10.6‑15.7)

14.7 (11.9‑18.5)

16.8 (13.2‑21.8)

19.8 (15.0‑26.7)

22.2 (16.3‑31.0)
20-day 4.49
(3.97‑5.18)

6.20 (5.47‑7.16)

8.54 (7.52‑9.90)

10.6 (9.22‑12.3)

13.4 (11.4‑16.2)

15.8 (13.1‑19.4)

18.2 (14.8‑23.0)

20.9 (16.5‑27.1)

24.8 (18.8‑33.4)

28.0 (20.5‑38.9)
30-day 5.33
(4.71‑6.16)

7.37 (6.50‑8.52)

10.2 (8.97‑11.8)

12.6 (11.0‑14.7)

16.1 (13.6‑19.4)

18.9 (15.7‑23.3)

22.0 (17.8‑27.7)

25.3 (19.9‑32.7)

30.0 (22.7‑40.5)

34.0 (24.9‑47.3)
45-day 6.32
(5.58‑7.30)

8.68 (7.66‑10.0)

12.0 (10.5‑13.9)

14.8 (12.9‑17.3)

18.9 (16.0‑22.8)

22.3 (18.5‑27.4)

25.9 (21.0‑32.7)

29.9 (23.6‑38.7)

35.6 (27.0‑48.0)

40.4 (29.6‑56.3)
60-day 7.33
(6.48‑8.46)

9.96 (8.79‑11.5)

13.6 (12.0‑15.8)

16.8 (14.7‑19.7)

21.5 (18.2‑26.0)

25.4 (21.0‑31.2)

29.5 (23.9‑37.2)

34.1 (26.9‑44.2)

40.8 (30.9‑55.0)

46.4 (34.0‑64.6)
1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).

Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.

Please refer to NOAA Atlas 14 document for more information.

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National Oceanic and Atmospheric Administration
National Weather Service
National Water Center
1325 East West Highway
Silver Spring, MD 20910
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NOAA Atlas 14, Volume 6, Version 2
Location name: Foothill Ranch, California, USA*
Latitude: 33.6766°, Longitude: -117.669°
Elevation: 779 ft**
* source: ESRI Maps
** source: USGS

POINT PRECIPITATION FREQUENCY ESTIMATES
Sanja Perica, Sarah Dietz, Sarah Heim, Lillian Hiner, Kazungu Maitaria, Deborah Martin, Sandra Pavlovic, Ishani Roy, Carl Trypaluk, Dale Unruh, Fenglin Yan, Michael Yekta, Tan Zhao, Geoffrey Bonnin, Daniel Brewer, Li-Chuan Chen, Tye Parzybok, John Yarchoan NOAA, National Weather Service, Silver Spring, Maryland PF_tabular | PF_graphical | Maps_&_aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour) 1 Duration
Average recurrence interval (years)
1 2 5 10 25 50 100 200 500 1000
5-min 1.64
(1.38‑1.97)

2.12 (1.78‑2.56)

2.77 (2.32‑3.36)

3.32 (2.75‑4.04)

4.08 (3.26‑5.15)

4.68 (3.65‑6.05)

5.30 (4.03‑7.03)

5.95 (4.40‑8.15)

6.88 (4.86‑9.83)

7.62 (5.20‑11.3)
10-min 1.18
(0.984‑1.42)

1.52 (1.28‑1.84)

1.99 (1.66‑2.41)

2.38 (1.97‑2.90)

2.92 (2.33‑3.69)

3.35 (2.62‑4.33)

3.80 (2.89‑5.04)

4.27 (3.16‑5.84)

4.93 (3.49‑7.04)

5.46 (3.72‑8.09)
15-min 0.948
(0.796‑1.14)

1.23 (1.03‑1.48)

1.60 (1.34‑1.94)

1.92 (1.59‑2.34)

2.36 (1.88‑2.98)

2.70 (2.11‑3.49)

3.06 (2.33‑4.06)

3.44 (2.54‑4.70)

3.98 (2.81‑5.68)

4.40 (3.00‑6.52)
30-min 0.670
(0.562‑0.806)

0.868
(0.728‑1.05)

1.14 (0.948‑1.37)

1.36 (1.12‑1.66)

1.67 (1.33‑2.11)

1.91 (1.49‑2.47)

2.17 (1.65‑2.87)

2.44 (1.80‑3.33)

2.81 (1.99‑4.02)

3.12 (2.12‑4.62)
60-min 0.468
(0.393‑0.564)

0.607
(0.509‑0.732)

0.793
(0.663‑0.959)

0.949
(0.786‑1.16)

1.16 (0.931‑1.47)

1.34 (1.04‑1.73)

1.52 (1.15‑2.01)

1.70 (1.26‑2.33)

1.97 (1.39‑2.81)

2.18 (1.48‑3.23)
2-hr 0.342
(0.287‑0.412)

0.440
(0.369‑0.531)

0.575
(0.481‑0.696)

0.690
(0.572‑0.842)

0.855
(0.683‑1.08)

0.988
(0.772‑1.28)

1.13 (0.860‑1.50)

1.28 (0.948‑1.75)

1.50 (1.06‑2.15)

1.68 (1.15‑2.49)
3-hr 0.285
(0.239‑0.343)

0.366
(0.307‑0.442)

0.479
(0.400‑0.579)

0.575
(0.476‑0.701)

0.714
(0.570‑0.902)

0.827
(0.647‑1.07)

0.949
(0.722‑1.26)

1.08 (0.799‑1.48)

1.27 (0.900‑1.82)

1.43 (0.977‑2.12)
6-hr 0.205
(0.172‑0.247)

0.264
(0.221‑0.318)

0.345
(0.288‑0.417)

0.414
(0.343‑0.505)

0.514
(0.411‑0.650)

0.596
(0.466‑0.771)

0.684
(0.521‑0.907)

0.779
(0.576‑1.06)

0.917
(0.648‑1.31)

1.03 (0.703‑1.53)
12-hr 0.134
(0.113‑0.162)

0.175
(0.146‑0.210)

0.229
(0.191‑0.277)

0.275
(0.228‑0.336)

0.341
(0.272‑0.431)

0.393
(0.307‑0.508)

0.448
(0.341‑0.594)

0.506
(0.374‑0.692)

0.589
(0.416‑0.841)

0.656
(0.447‑0.972)
24-hr 0.089
(0.079‑0.103)

0.117
(0.103‑0.136)

0.155
(0.137‑0.180)

0.187
(0.163‑0.218)

0.231
(0.195‑0.279)

0.266
(0.220‑0.327)

0.302
(0.245‑0.381)

0.340
(0.268‑0.441)

0.393
(0.298‑0.530)

0.436
(0.319‑0.607)
2-day 0.054
(0.047‑0.062)

0.072
(0.063‑0.083)

0.096
(0.085‑0.112)

0.117
(0.102‑0.137)

0.146
(0.123‑0.176)

0.168
(0.140‑0.207)

0.192
(0.156‑0.242)

0.217
(0.171‑0.282)

0.253
(0.191‑0.341)

0.281
(0.206‑0.392)
3-day 0.038
(0.034‑0.044)

0.052
(0.046‑0.060)

0.070
(0.062‑0.081)

0.086
(0.075‑0.100)

0.107
(0.091‑0.129)

0.125
(0.103‑0.153)

0.143
(0.115‑0.180)

0.162
(0.128‑0.210)

0.189
(0.143‑0.255)

0.211
(0.155‑0.295)
4-day 0.031
(0.027‑0.036)

0.042
(0.037‑0.049)

0.057
(0.050‑0.066)

0.070
(0.061‑0.082)

0.088
(0.074‑0.106)

0.103
(0.085‑0.126)

0.118
(0.095‑0.149)

0.134
(0.106‑0.174)

0.157
(0.119‑0.212)

0.176
(0.129‑0.245)
7-day 0.020
(0.018‑0.023)

0.028
(0.024‑0.032)

0.038
(0.033‑0.044)

0.046
(0.040‑0.054)

0.059
(0.050‑0.071)

0.069
(0.057‑0.084)

0.079
(0.064‑0.100)

0.090
(0.071‑0.117)

0.106
(0.080‑0.143)

0.119
(0.087‑0.166)
10-day 0.015
(0.013‑0.018)

0.021
(0.018‑0.024)

0.029
(0.025‑0.033)

0.035
(0.031‑0.042)

0.045
(0.038‑0.054)

0.053
(0.044‑0.065)

0.061
(0.049‑0.077)

0.070
(0.055‑0.090)

0.082
(0.062‑0.111)

0.092
(0.067‑0.129)
20-day 0.009
(0.008‑0.010)

0.012
(0.011‑0.014)

0.017
(0.015‑0.020)

0.021
(0.019‑0.025)

0.027
(0.023‑0.033)

0.032
(0.027‑0.040)

0.038
(0.030‑0.047)

0.043
(0.034‑0.056)

0.051
(0.039‑0.069)

0.058
(0.042‑0.081)
30-day 0.007
(0.006‑0.008)

0.010
(0.009‑0.011)

0.014
(0.012‑0.016)

0.017
(0.015‑0.020)

0.022
(0.018‑0.026)

0.026
(0.021‑0.032)

0.030
(0.024‑0.038)

0.035
(0.027‑0.045)

0.041
(0.031‑0.056)

0.047
(0.034‑0.065)
45-day 0.005
(0.005‑0.006)

0.008
(0.007‑0.009)

0.011
(0.009‑0.012)

0.013
(0.011‑0.016)

0.017
(0.014‑0.021)

0.020
(0.017‑0.025)

0.023
(0.019‑0.030)

0.027
(0.021‑0.035)

0.033
(0.024‑0.044)

0.037
(0.027‑0.052)
60-day 0.005
(0.004‑0.005)

0.006
(0.006‑0.007)

0.009
(0.008‑0.010)

0.011
(0.010‑0.013)

0.014
(0.012‑0.018)

0.017
(0.014‑0.021)

0.020
(0.016‑0.025)

0.023
(0.018‑0.030)

0.028
(0.021‑0.038)

0.032
(0.023‑0.044)
1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).

Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.

Please refer to NOAA Atlas 14 document for more information.

Back to Top
PF graphical
Item: 11
1343
Back to Top
Maps & aerials
Small scale terrain
Item: 11
1344
Large scale terrain
Large scale map
Large scale aerial
+
–
3km
2mi
+
–
100km
60mi
+
–
100km
60mi
Item: 11
1345
Back to Top
US Department of Commerce
National Oceanic and Atmospheric Administration
National Weather Service
National Water Center
1325 East West Highway
Silver Spring, MD 20910
Questions?: [email protected]
Disclaimer
+
–
100km
60mi
Item: 11
1346
10 Costco Foothill Ranch Preliminary Hydrology Report
November 2025
Appendix B - FIRM MAP
Item: 11
1347
National Flood Hazard Layer FIRMette
0 250 500 1,000 1,500 2,000
Feet
Ü

SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT

SPECIAL FLOOD

HAZARD AREAS
Without Base Flood Elevation (BFE)
Zone A, V, A99
With BFE or Depth Zone AE, AO, AH, VE, AR
Regulatory Floodway

0.2% Annual Chance Flood Hazard, Areas
of 1% annual chance flood with average
depth less than one foot or with drainage
areas of less than one square mile Zone X
Future Conditions 1% Annual
Chance Flood Hazard Zone X
Area with Reduced Flood Risk due to
Levee. See Notes. Zone X
Area with Flood Risk due to Levee Zone D
NO SCREEN Area of Minimal Flood Hazard Zone X
Area of Undetermined Flood Hazard Zone D
Channel, Culvert, or Storm Sewer
Levee, Dike, or Floodwall
Cross Sections with 1% Annual Chance

17.5 Water Surface Elevation
Coastal Transect
Coastal Transect Baseline
Profile Baseline
Hydrographic Feature
Base Flood Elevation Line (BFE)
Effective LOMRs
Limit of Study
Jurisdiction Boundary
Digital Data Available
No Digital Data Available
Unmapped
This map complies with FEMA's standards for the use of
digital flood maps if it is not void as described below.

The basemap shown complies with FEMA's basemap
accuracy standards
The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 5/16/2025 at 6:04 PM and does not
reflect changes or amendments subsequent to this date and time. The NFHL and effective information may change or
become superseded by new data over time.

This map image is void if the one or more of the following map elements do not appear: basemap imagery, flood zone labels, legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for unmapped and unmodernized areas cannot be used for
regulatory purposes.

Legend

OTHER AREAS OF

FLOOD HAZARD

OTHER AREAS

GENERAL

STRUCTURES
OTHER

FEATURES

MAP PANELS
8 B

20.2 The pin displayed on the map is an approximate
point selected by the user and does not represent
an authoritative property location.
1:6,000
117°40'27"W 33°40'51"N
117°39'49"W 33°40'21"N
Basemap Imagery Source: USGS National Map 2023
Item: 11
1348
11 Costco Foothill Ranch Preliminary Hydrology Report
November 2025
Appendix C – Soils Information
Item: 11
1349

MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.

Warning: Soil Map may not be valid at this scale.

Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale.

Please rely on the bar scale on each map sheet for map
measurements.

Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:

Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required.

This product is generated from the USDA-NRCS certified data as of the version date(s) listed below.

Soil Survey Area: Orange County and Part of Riverside County, California
Survey Area Data: Version 18, Aug 30, 2024
Soil map units are labeled (as space allows) for map scales 1:50,000 or larger.

Date(s) aerial images were photographed: Jan 17, 2023—Feb 8, 2023
The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident.

Soil Map—Orange County and Part of Riverside County, California Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
5/16/2025

Item: 11
1350
Soil Map—Orange County and Part of Riverside County, California Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
5/16/2025

3726380 3726450 3726520 3726590 3726660 3726730 3726800 3726380 3726450 3726520 3726590 3726660 3726730 3726800 437730 437800 437870 437940 438010 438080 438150 438220 438290 438360 437730 437800 437870 437940 438010 438080 438150 438220 438290 438360 33° 40' 45'' N
117° 40' 19'' W
33° 40' 45'' N
117° 39' 52'' W
33° 40' 31'' N
117° 40' 19'' W
33° 40' 31'' N
117° 39' 52'' W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 11N WGS84 0 150 300 600 900
Feet
0 45 90 180 270
Meters
Map Scale: 1:3,160 if printed on A landscape (11" x 8.5") sheet.

Soil Map may not be valid at this scale.

Item: 11
1351
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 136 Capistrano sandy loam, 9 to 15
percent slopes

0.2 1.0%
142 Cieneba sandy loam, 30 to 75
percent slopes, eroded

4.4 24.7%
177 Myford sandy loam, 9 to 30
percent slopes, eroded

13.2 74.2%
Totals for Area of Interest 17.8 100.0%
Soil Map—Orange County and Part of Riverside County, California Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
5/16/2025

Item: 11
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12 Costco Foothill Ranch Preliminary Hydrology Report
November 2025
Appendix D - Existing and Proposed
Drainage Maps
Item: 11
1353
B.2 4.32 C.1 1.56 D.1 0.64 A 1.51D.2 1.23 D.3 2.14 B.1 2.15 C.2 2.38 Know what's before you dig. below. Call 811 R LEGEND DRAINAGE SUMMARY X XXX TOWNE CENTRE DRMARKET (PRIVATE ROAD) HYDROLOGY INFORMATION COSTCO - FOOTHILL RANCH PRE-DEVELOPMENT HYDROLOGY EXHIBIT TOWNE CENTRE AND MARKET © 1 NORTH FOOTHILL TRANSPORTATION CORRIDOR 1354
v v v ENTRY EXIT
RESTRICTED ELECTRIC VEHICLES ONLY RESTRICTED ELECTRIC VEHICLES ONLY v A3 2.37 A7.2 2.26A6 1.30 A5 0.34 A1 2.83 A2 1.65A4.1 1.38 A4 3.10 A7.1 0.70 LEGEND HYDROLOGY INFORMATION X XXX COSTCO - FOOTHILL RANCH POST-DEVELOPMENT HYDROLOGY EXHIBIT TOWNE CENTRE AND MARKET © 2 DRAINAGE NOTES NORTH Know what's before you dig. below. Call 811 R HYDROLOGY SUMMARY Δ

TOWNE CENTRE DR

MARKET (PRIVATE ROAD)

FOOTHILL TRANSPORTATION CORRIDOR
1355
13 Costco Foothill Ranch Preliminary Hydrology Report
November 2025
Appendix E - Rational Method Analysis
Item: 11
1356
____________________________________________________________________________ ****************************************************************************

RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
(Reference: 1986 ORANGE COUNTY HYDROLOGY CRITERION)
(c) Copyright 1983-2016 Advanced Engineering Software (aes) Ver. 23.0 Release Date: 07/01/2016 License ID 1499
Analysis prepared by:

************************** DESCRIPTION OF STUDY ************************** * COSTCO FOOTHILL RANCH *
* EXISTING 2 YEAR RATIONAL METHOD *
* KIMLEY-HORN *
************************************************************************** FILE NAME: FRRME2YR.DAT
TIME/DATE OF STUDY: 11:11 09/17/2025
============================================================================ USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
============================================================================ --*TIME-OF-CONCENTRATION MODEL*--
USER SPECIFIED STORM EVENT(YEAR) = 2.00
SPECIFIED MINIMUM PIPE SIZE(INCH) = 6.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95 *DATA BANK RAINFALL USED*
*ANTECEDENT MOISTURE CONDITION (AMC) I ASSUMED FOR RATIONAL METHOD* *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING

WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
=== ===== ========= ================= ====== ===== ====== ===== ======= 1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0313 0.167 0.0150 GLOBAL STREET FLOW-DEPTH CONSTRAINTS:

1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)

2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
*USER-SPECIFIED MINIMUM TOPOGRAPHIC SLOPE ADJUSTMENT NOT SELECTED **************************************************************************** FLOW PROCESS FROM NODE 1.10 TO NODE 1.20 IS CODE = 21
Item: 11
1357
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 314.00
ELEVATION DATA: UPSTREAM(FEET) = 783.30 DOWNSTREAM(FEET) = 775.81 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 6.399
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.965
SUBAREA Tc AND LOSS RATE DATA(AMC I ):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 1.45 0.25 0.100 50 6.40
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 2.53
TOTAL AREA(ACRES) = 1.45 PEAK FLOW RATE(CFS) = 2.53
**************************************************************************** FLOW PROCESS FROM NODE 2.10 TO NODE 2.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 301.00
ELEVATION DATA: UPSTREAM(FEET) = 787.52 DOWNSTREAM(FEET) = 782.97 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 6.893
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.883
SUBAREA Tc AND LOSS RATE DATA(AMC I ):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 2.04 0.25 0.100 50 6.89
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 3.41
TOTAL AREA(ACRES) = 2.04 PEAK FLOW RATE(CFS) = 3.41
**************************************************************************** FLOW PROCESS FROM NODE 2.20 TO NODE 2.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 782.97 DOWNSTREAM(FEET) = 776.77 CHANNEL LENGTH THRU SUBAREA(FEET) = 301.00 CHANNEL SLOPE = 0.0206 CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
Item: 11
1358
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.634
SUBAREA LOSS RATE DATA(AMC I ):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 4.14 0.25 0.100 50
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 6.41
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 2.60 AVERAGE FLOW DEPTH(FEET) = 0.13 TRAVEL TIME(MIN.) = 1.93 Tc(MIN.) = 8.82
SUBAREA AREA(ACRES) = 4.14 SUBAREA RUNOFF(CFS) = 6.00
EFFECTIVE AREA(ACRES) = 6.18 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 6.2 PEAK FLOW RATE(CFS) = 8.95
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.16 FLOW VELOCITY(FEET/SEC.) = 2.82
LONGEST FLOWPATH FROM NODE 2.10 TO NODE 2.30 = 602.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 3.10 TO NODE 3.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 189.00
ELEVATION DATA: UPSTREAM(FEET) = 782.48 DOWNSTREAM(FEET) = 778.16 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.268
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 2.197
SUBAREA Tc AND LOSS RATE DATA(AMC I ):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 1.58 0.25 0.100 50 5.27
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 3.09
TOTAL AREA(ACRES) = 1.58 PEAK FLOW RATE(CFS) = 3.09
**************************************************************************** FLOW PROCESS FROM NODE 3.20 TO NODE 3.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 778.16 DOWNSTREAM(FEET) = 774.54 CHANNEL LENGTH THRU SUBAREA(FEET) = 189.00 CHANNEL SLOPE = 0.0192 CHANNEL BASE(FEET) = 85.00 "Z" FACTOR = 99.000
Item: 11
1359
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.809
SUBAREA LOSS RATE DATA(AMC I ):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 1.90 0.25 0.100 50
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 4.63
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 1.48 AVERAGE FLOW DEPTH(FEET) = 0.04 TRAVEL TIME(MIN.) = 2.12 Tc(MIN.) = 7.39
SUBAREA AREA(ACRES) = 1.90 SUBAREA RUNOFF(CFS) = 3.05
EFFECTIVE AREA(ACRES) = 3.48 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 3.5 PEAK FLOW RATE(CFS) = 5.59
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.04 FLOW VELOCITY(FEET/SEC.) = 1.53
LONGEST FLOWPATH FROM NODE 3.10 TO NODE 3.30 = 378.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.10 TO NODE 4.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 329.00
ELEVATION DATA: UPSTREAM(FEET) = 777.53 DOWNSTREAM(FEET) = 776.74 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 10.320
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.493
SUBAREA Tc AND LOSS RATE DATA(AMC I ):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 0.64 0.25 0.100 50 10.32
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 0.85
TOTAL AREA(ACRES) = 0.64 PEAK FLOW RATE(CFS) = 0.85
**************************************************************************** FLOW PROCESS FROM NODE 4.20 TO NODE 4.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 776.74 DOWNSTREAM(FEET) = 776.52 CHANNEL LENGTH THRU SUBAREA(FEET) = 168.00 CHANNEL SLOPE = 0.0013 Item: 11
1360
CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.216
SUBAREA LOSS RATE DATA(AMC I ):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 1.23 0.25 0.100 50
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.51
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 0.63 AVERAGE FLOW DEPTH(FEET) = 0.13 TRAVEL TIME(MIN.) = 4.45 Tc(MIN.) = 14.77
SUBAREA AREA(ACRES) = 1.23 SUBAREA RUNOFF(CFS) = 1.32
EFFECTIVE AREA(ACRES) = 1.87 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 1.9 PEAK FLOW RATE(CFS) = 2.00
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.15 FLOW VELOCITY(FEET/SEC.) = 0.69
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.30 = 497.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.30 TO NODE 4.40 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 776.52 DOWNSTREAM(FEET) = 774.63 CHANNEL LENGTH THRU SUBAREA(FEET) = 272.00 CHANNEL SLOPE = 0.0069 CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.085
SUBAREA LOSS RATE DATA(AMC I ):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 2.15 0.25 0.100 50
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 3.03
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 1.40 AVERAGE FLOW DEPTH(FEET) = 0.12 TRAVEL TIME(MIN.) = 3.24 Tc(MIN.) = 18.01
SUBAREA AREA(ACRES) = 2.15 SUBAREA RUNOFF(CFS) = 2.05
EFFECTIVE AREA(ACRES) = 4.02 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 4.0 PEAK FLOW RATE(CFS) = 3.83
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.13 FLOW VELOCITY(FEET/SEC.) = 1.56
Item: 11
1361
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.40 = 769.00 FEET. ============================================================================ END OF STUDY SUMMARY:

TOTAL AREA(ACRES) = 4.0 TC(MIN.) = 18.01
EFFECTIVE AREA(ACRES) = 4.02 AREA-AVERAGED Fm(INCH/HR)= 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.100 PEAK FLOW RATE(CFS) = 3.83
============================================================================ ============================================================================

END OF RATIONAL METHOD ANALYSIS

Item: 11
1362
____________________________________________________________________________ ****************************************************************************

RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
(Reference: 1986 ORANGE COUNTY HYDROLOGY CRITERION)
(c) Copyright 1983-2016 Advanced Engineering Software (aes) Ver. 23.0 Release Date: 07/01/2016 License ID 1499
Analysis prepared by:

************************** DESCRIPTION OF STUDY ************************** * COSTCO FOOTHILL RANCH *
* EXISTING 100 YEAR RATIONAL METHOD *
* KIMLEY-HORN *
************************************************************************** FILE NAME: FRRME2YR.DAT
TIME/DATE OF STUDY: 11:21 09/17/2025
============================================================================ USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
============================================================================ --*TIME-OF-CONCENTRATION MODEL*--
USER SPECIFIED STORM EVENT(YEAR) = 100.00
SPECIFIED MINIMUM PIPE SIZE(INCH) = 6.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95 *DATA BANK RAINFALL USED*
*ANTECEDENT MOISTURE CONDITION (AMC) III ASSUMED FOR RATIONAL METHOD* *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING

WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
=== ===== ========= ================= ====== ===== ====== ===== ======= 1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0312 0.167 0.0150 GLOBAL STREET FLOW-DEPTH CONSTRAINTS:

1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)

2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
*USER-SPECIFIED MINIMUM TOPOGRAPHIC SLOPE ADJUSTMENT NOT SELECTED **************************************************************************** FLOW PROCESS FROM NODE 1.10 TO NODE 1.20 IS CODE = 21
Item: 11
1363
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 314.00
ELEVATION DATA: UPSTREAM(FEET) = 783.30 DOWNSTREAM(FEET) = 775.81 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 6.399
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.371
SUBAREA Tc AND LOSS RATE DATA(AMC III):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 1.45 0.25 0.100 86 6.40
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 6.98
TOTAL AREA(ACRES) = 1.45 PEAK FLOW RATE(CFS) = 6.98
**************************************************************************** FLOW PROCESS FROM NODE 2.10 TO NODE 2.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 301.00
ELEVATION DATA: UPSTREAM(FEET) = 787.52 DOWNSTREAM(FEET) = 782.97 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 6.893
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.148
SUBAREA Tc AND LOSS RATE DATA(AMC III):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 2.04 0.25 0.100 86 6.89
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 9.40
TOTAL AREA(ACRES) = 2.04 PEAK FLOW RATE(CFS) = 9.40
**************************************************************************** FLOW PROCESS FROM NODE 2.20 TO NODE 2.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 782.97 DOWNSTREAM(FEET) = 776.77 CHANNEL LENGTH THRU SUBAREA(FEET) = 301.00 CHANNEL SLOPE = 0.0206 CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
Item: 11
1364
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 4.599
SUBAREA LOSS RATE DATA(AMC III):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 4.14 0.25 0.100 86
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 17.96
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 3.35 AVERAGE FLOW DEPTH(FEET) = 0.21 TRAVEL TIME(MIN.) = 1.50 Tc(MIN.) = 8.39
SUBAREA AREA(ACRES) = 4.14 SUBAREA RUNOFF(CFS) = 17.04
EFFECTIVE AREA(ACRES) = 6.18 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 6.2 PEAK FLOW RATE(CFS) = 25.44
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.24 FLOW VELOCITY(FEET/SEC.) = 3.70
LONGEST FLOWPATH FROM NODE 2.10 TO NODE 2.30 = 602.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 3.10 TO NODE 3.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 189.00
ELEVATION DATA: UPSTREAM(FEET) = 782.48 DOWNSTREAM(FEET) = 778.16 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.268
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 6.005
SUBAREA Tc AND LOSS RATE DATA(AMC III):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 1.58 0.25 0.100 86 5.27
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 8.50
TOTAL AREA(ACRES) = 1.58 PEAK FLOW RATE(CFS) = 8.50
**************************************************************************** FLOW PROCESS FROM NODE 3.20 TO NODE 3.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 778.16 DOWNSTREAM(FEET) = 774.54 CHANNEL LENGTH THRU SUBAREA(FEET) = 189.00 CHANNEL SLOPE = 0.0192 CHANNEL BASE(FEET) = 85.00 "Z" FACTOR = 99.000
Item: 11
1365
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.218
SUBAREA LOSS RATE DATA(AMC III):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 1.90 0.25 0.100 86
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 12.97
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 2.15 AVERAGE FLOW DEPTH(FEET) = 0.07 TRAVEL TIME(MIN.) = 1.46 Tc(MIN.) = 6.73
SUBAREA AREA(ACRES) = 1.90 SUBAREA RUNOFF(CFS) = 8.88
EFFECTIVE AREA(ACRES) = 3.48 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 3.5 PEAK FLOW RATE(CFS) = 16.27
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.07 FLOW VELOCITY(FEET/SEC.) = 2.40
LONGEST FLOWPATH FROM NODE 3.10 TO NODE 3.30 = 378.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.10 TO NODE 4.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 329.00
ELEVATION DATA: UPSTREAM(FEET) = 777.53 DOWNSTREAM(FEET) = 776.74 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 10.320
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 4.085
SUBAREA Tc AND LOSS RATE DATA(AMC III):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 0.64 0.25 0.100 86 10.32
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 2.34
TOTAL AREA(ACRES) = 0.64 PEAK FLOW RATE(CFS) = 2.34
**************************************************************************** FLOW PROCESS FROM NODE 4.20 TO NODE 4.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 776.74 DOWNSTREAM(FEET) = 776.52 CHANNEL LENGTH THRU SUBAREA(FEET) = 168.00 CHANNEL SLOPE = 0.0013 Item: 11
1366
CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 3.476
SUBAREA LOSS RATE DATA(AMC III):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 1.23 0.25 0.100 86
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 4.26
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 0.83 AVERAGE FLOW DEPTH(FEET) = 0.20 TRAVEL TIME(MIN.) = 3.36 Tc(MIN.) = 13.68
SUBAREA AREA(ACRES) = 1.23 SUBAREA RUNOFF(CFS) = 3.82
EFFECTIVE AREA(ACRES) = 1.87 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 1.9 PEAK FLOW RATE(CFS) = 5.81
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.23 FLOW VELOCITY(FEET/SEC.) = 0.90
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.30 = 497.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.30 TO NODE 4.40 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 776.52 DOWNSTREAM(FEET) = 774.63 CHANNEL LENGTH THRU SUBAREA(FEET) = 272.00 CHANNEL SLOPE = 0.0069 CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 3.169
SUBAREA LOSS RATE DATA(AMC III):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 2.15 0.25 0.100 86
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 8.85
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 1.89 AVERAGE FLOW DEPTH(FEET) = 0.19 TRAVEL TIME(MIN.) = 2.40 Tc(MIN.) = 16.07
SUBAREA AREA(ACRES) = 2.15 SUBAREA RUNOFF(CFS) = 6.08
EFFECTIVE AREA(ACRES) = 4.02 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 4.0 PEAK FLOW RATE(CFS) = 11.38
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.22 FLOW VELOCITY(FEET/SEC.) = 1.99
Item: 11
1367
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.40 = 769.00 FEET. ============================================================================ END OF STUDY SUMMARY:

TOTAL AREA(ACRES) = 4.0 TC(MIN.) = 16.07
EFFECTIVE AREA(ACRES) = 4.02 AREA-AVERAGED Fm(INCH/HR)= 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.100 PEAK FLOW RATE(CFS) = 11.38
============================================================================ ============================================================================

END OF RATIONAL METHOD ANALYSIS

Item: 11
1368
____________________________________________________________________________ ****************************************************************************

RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
(Reference: 1986 ORANGE COUNTY HYDROLOGY CRITERION)
(c) Copyright 1983-2016 Advanced Engineering Software (aes) Ver. 23.0 Release Date: 07/01/2016 License ID 1499
Analysis prepared by:

************************** DESCRIPTION OF STUDY ************************** * COSTCO FOOTHILL RANCH *
* PROPOSED 2 YEAR RATIONAL METHOD *
* KIMLEY-HORN *
************************************************************************** FILE NAME: FRRM2YP.DAT
TIME/DATE OF STUDY: 10:48 09/18/2025
============================================================================ USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
============================================================================ --*TIME-OF-CONCENTRATION MODEL*--
USER SPECIFIED STORM EVENT(YEAR) = 2.00
SPECIFIED MINIMUM PIPE SIZE(INCH) = 6.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95 *DATA BANK RAINFALL USED*
*ANTECEDENT MOISTURE CONDITION (AMC) II ASSUMED FOR RATIONAL METHOD* *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING

WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
=== ===== ========= ================= ====== ===== ====== ===== ======= 1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0312 0.167 0.0150 GLOBAL STREET FLOW-DEPTH CONSTRAINTS:

1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)

2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
*USER-SPECIFIED MINIMUM TOPOGRAPHIC SLOPE ADJUSTMENT NOT SELECTED **************************************************************************** FLOW PROCESS FROM NODE 1.10 TO NODE 1.20 IS CODE = 21
Item: 11
1369
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 330.00
ELEVATION DATA: UPSTREAM(FEET) = 785.09 DOWNSTREAM(FEET) = 780.16 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 7.168
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.841
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 2.72 0.25 0.100 69 7.17
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 4.45
TOTAL AREA(ACRES) = 2.72 PEAK FLOW RATE(CFS) = 4.45
**************************************************************************** FLOW PROCESS FROM NODE 1.20 TO NODE 2.20 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 775.54 DOWNSTREAM(FEET) = 774.90 FLOW LENGTH(FEET) = 128.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 12.3 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.14
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 4.45
PIPE TRAVEL TIME(MIN.) = 0.52 Tc(MIN.) = 7.68
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 2.20 = 458.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 2.20 TO NODE 2.20 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 7.68
RAINFALL INTENSITY(INCH/HR) = 1.77
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 2.72
TOTAL STREAM AREA(ACRES) = 2.72
PEAK FLOW RATE(CFS) AT CONFLUENCE = 4.45
Item: 11
1370
**************************************************************************** FLOW PROCESS FROM NODE 2.10 TO NODE 2.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 220.00
ELEVATION DATA: UPSTREAM(FEET) = 784.75 DOWNSTREAM(FEET) = 780.45 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.776
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 2.084
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 1.49 0.25 0.100 69 5.78
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 2.76
TOTAL AREA(ACRES) = 1.49 PEAK FLOW RATE(CFS) = 2.76
**************************************************************************** FLOW PROCESS FROM NODE 2.20 TO NODE 2.20 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 5.78
RAINFALL INTENSITY(INCH/HR) = 2.08
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 1.49
TOTAL STREAM AREA(ACRES) = 1.49
PEAK FLOW RATE(CFS) AT CONFLUENCE = 2.76
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 4.45 7.68 1.769 0.25( 0.03) 0.10 2.7 1.10
2 2.76 5.78 2.084 0.25( 0.03) 0.10 1.5 2.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
Item: 11
1371
1 6.71 5.78 2.084 0.25( 0.02) 0.10 3.5 2.10
2 6.78 7.68 1.769 0.25( 0.03) 0.10 4.2 1.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 6.78 Tc(MIN.) = 7.68
EFFECTIVE AREA(ACRES) = 4.21 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 4.2
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 2.20 = 458.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 2.30 TO NODE 3.30 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 774.80 DOWNSTREAM(FEET) = 773.75 FLOW LENGTH(FEET) = 136.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 18.0 INCH PIPE IS 11.7 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 5.59
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 6.78
PIPE TRAVEL TIME(MIN.) = 0.41 Tc(MIN.) = 8.09
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 3.30 = 594.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 3.30 TO NODE 3.30 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 8.09
RAINFALL INTENSITY(INCH/HR) = 1.72
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 4.21
TOTAL STREAM AREA(ACRES) = 4.21
PEAK FLOW RATE(CFS) AT CONFLUENCE = 6.78
**************************************************************************** FLOW PROCESS FROM NODE 3.10 TO NODE 3.20 IS CODE = 22
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>>>>USE SPECIFIED Tc VALUE FOR INITIAL SUBAREA<<<
============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 136.00
USER SPECIFIED Tc(MIN.) = 5.000
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 2.264
Item: 11
1372
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 2.31 0.25 0.100 69
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 4.65
TOTAL AREA(ACRES) = 2.31 PEAK FLOW RATE(CFS) = 4.65
**************************************************************************** FLOW PROCESS FROM NODE 3.20 TO NODE 3.30 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 778.22 DOWNSTREAM(FEET) = 773.75 FLOW LENGTH(FEET) = 265.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 8.1 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.88
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 4.65
PIPE TRAVEL TIME(MIN.) = 0.64 Tc(MIN.) = 5.64
LONGEST FLOWPATH FROM NODE 3.10 TO NODE 3.30 = 401.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 3.30 TO NODE 3.30 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 5.64
RAINFALL INTENSITY(INCH/HR) = 2.11
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 2.31
TOTAL STREAM AREA(ACRES) = 2.31
PEAK FLOW RATE(CFS) AT CONFLUENCE = 4.65
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 6.71 6.18 2.004 0.25( 0.02) 0.10 3.5 2.10
1 6.78 8.09 1.717 0.25( 0.03) 0.10 4.2 1.10
2 4.65 5.64 2.112 0.25( 0.03) 0.10 2.3 3.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.

Item: 11
1373
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 11.11 5.64 2.112 0.25( 0.02) 0.10 5.5 3.10
2 11.12 6.18 2.004 0.25( 0.03) 0.10 5.8 2.10
3 10.56 8.09 1.717 0.25( 0.03) 0.10 6.5 1.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 11.12 Tc(MIN.) = 6.18
EFFECTIVE AREA(ACRES) = 5.84 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 6.5
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 3.30 = 594.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 3.30 TO NODE 4.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 773.65 DOWNSTREAM(FEET) = 769.47 FLOW LENGTH(FEET) = 97.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 10.6 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 11.96
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 11.12
PIPE TRAVEL TIME(MIN.) = 0.14 Tc(MIN.) = 6.32
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 4.40 = 691.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.40 TO NODE 4.40 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 6.32
RAINFALL INTENSITY(INCH/HR) = 1.98
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 5.84
TOTAL STREAM AREA(ACRES) = 6.52
PEAK FLOW RATE(CFS) AT CONFLUENCE = 11.12
**************************************************************************** FLOW PROCESS FROM NODE 4.10 TO NODE 4.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
Item: 11
1374
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 214.00
ELEVATION DATA: UPSTREAM(FEET) = 784.71 DOWNSTREAM(FEET) = 780.40 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.678
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 2.104
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 1.36 0.25 0.100 69 5.68
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 2.55
TOTAL AREA(ACRES) = 1.36 PEAK FLOW RATE(CFS) = 2.55
**************************************************************************** FLOW PROCESS FROM NODE 4.20 TO NODE 4.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 780.40 DOWNSTREAM(FEET) = 775.74 CHANNEL LENGTH THRU SUBAREA(FEET) = 237.00 CHANNEL SLOPE = 0.0197 CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.811
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 3.09 0.25 0.100 69
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 5.04
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 2.32 AVERAGE FLOW DEPTH(FEET) = 0.12 TRAVEL TIME(MIN.) = 1.70 Tc(MIN.) = 7.38
SUBAREA AREA(ACRES) = 3.09 SUBAREA RUNOFF(CFS) = 4.97
EFFECTIVE AREA(ACRES) = 4.45 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 4.4 PEAK FLOW RATE(CFS) = 7.15
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.14 FLOW VELOCITY(FEET/SEC.) = 2.64
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.30 = 451.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.30 TO NODE 4.40 IS CODE = 31
---------------------------------------------------------------------------- Item: 11
1375
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 771.14 DOWNSTREAM(FEET) = 769.66 FLOW LENGTH(FEET) = 296.40 MANNING'S N = 0.013
DEPTH OF FLOW IN 18.0 INCH PIPE IS 14.6 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.67
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 7.15
PIPE TRAVEL TIME(MIN.) = 1.06 Tc(MIN.) = 8.44
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.40 = 747.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.40 TO NODE 4.40 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 8.44
RAINFALL INTENSITY(INCH/HR) = 1.68
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 4.45
TOTAL STREAM AREA(ACRES) = 4.45
PEAK FLOW RATE(CFS) AT CONFLUENCE = 7.15
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 11.11 5.78 2.083 0.25( 0.02) 0.10 5.5 3.10
1 11.12 6.32 1.979 0.25( 0.03) 0.10 5.8 2.10
1 10.56 8.23 1.701 0.25( 0.03) 0.10 6.5 1.10
2 7.15 8.44 1.677 0.25( 0.03) 0.10 4.4 4.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 17.21 5.78 2.083 0.25( 0.02) 0.10 8.6 3.10
2 17.46 6.32 1.979 0.25( 0.03) 0.10 9.2 2.10
3 17.63 8.23 1.701 0.25( 0.03) 0.10 10.9 1.10
4 17.56 8.44 1.677 0.25( 0.03) 0.10 11.0 4.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 17.63 Tc(MIN.) = 8.23
Item: 11
1376
EFFECTIVE AREA(ACRES) = 10.86 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 11.0
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.40 = 747.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.40 TO NODE 6.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 769.66 DOWNSTREAM(FEET) = 767.76 FLOW LENGTH(FEET) = 342.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 27.0 INCH PIPE IS 18.0 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.26
ESTIMATED PIPE DIAMETER(INCH) = 27.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 17.63
PIPE TRAVEL TIME(MIN.) = 0.91 Tc(MIN.) = 9.14
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 6.40 = 1089.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 6.40 IS CODE = 10
---------------------------------------------------------------------------- >>>>>MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK # 1 <<<<< ============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 6.40 IS CODE = 13
---------------------------------------------------------------------------- >>>>>CLEAR THE MAIN-STREAM MEMORY<<<<<
============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 5.10 TO NODE 5.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 229.00
ELEVATION DATA: UPSTREAM(FEET) = 784.59 DOWNSTREAM(FEET) = 784.09 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 9.099
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.605
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 0.41 0.25 0.100 69 9.10
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
Item: 11
1377
SUBAREA RUNOFF(CFS) = 0.58
TOTAL AREA(ACRES) = 0.41 PEAK FLOW RATE(CFS) = 0.58
**************************************************************************** FLOW PROCESS FROM NODE 5.20 TO NODE 6.30 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 779.49 DOWNSTREAM(FEET) = 778.11 FLOW LENGTH(FEET) = 142.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 9.0 INCH PIPE IS 3.8 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 3.33
ESTIMATED PIPE DIAMETER(INCH) = 9.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 0.58
PIPE TRAVEL TIME(MIN.) = 0.71 Tc(MIN.) = 9.81
LONGEST FLOWPATH FROM NODE 5.10 TO NODE 6.30 = 371.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.30 TO NODE 6.30 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 9.81
RAINFALL INTENSITY(INCH/HR) = 1.54
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 0.41
TOTAL STREAM AREA(ACRES) = 0.41
PEAK FLOW RATE(CFS) AT CONFLUENCE = 0.58
**************************************************************************** FLOW PROCESS FROM NODE 6.10 TO NODE 6.20 IS CODE = 22
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>>>>USE SPECIFIED Tc VALUE FOR INITIAL SUBAREA<<<
============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 142.00
USER SPECIFIED Tc(MIN.) = 5.000
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 2.264
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 1.26 0.25 0.100 69
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 2.54
Item: 11
1378
TOTAL AREA(ACRES) = 1.26 PEAK FLOW RATE(CFS) = 2.54
**************************************************************************** FLOW PROCESS FROM NODE 6.20 TO NODE 6.30 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 778.22 DOWNSTREAM(FEET) = 778.11 FLOW LENGTH(FEET) = 22.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 8.1 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 3.74
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 2.54
PIPE TRAVEL TIME(MIN.) = 0.10 Tc(MIN.) = 5.10
LONGEST FLOWPATH FROM NODE 6.10 TO NODE 6.30 = 164.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.30 TO NODE 6.30 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 5.10
RAINFALL INTENSITY(INCH/HR) = 2.24
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 1.26
TOTAL STREAM AREA(ACRES) = 1.26
PEAK FLOW RATE(CFS) AT CONFLUENCE = 2.54
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 0.58 9.81 1.538 0.25( 0.03) 0.10 0.4 5.10
2 2.54 5.10 2.239 0.25( 0.03) 0.10 1.3 6.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 2.98 5.10 2.239 0.25( 0.03) 0.10 1.5 6.10
2 2.32 9.81 1.538 0.25( 0.03) 0.10 1.7 5.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

Item: 11
1379
PEAK FLOW RATE(CFS) = 2.98 Tc(MIN.) = 5.10
EFFECTIVE AREA(ACRES) = 1.47 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 1.7
LONGEST FLOWPATH FROM NODE 5.10 TO NODE 6.30 = 371.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.30 TO NODE 6.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 778.11 DOWNSTREAM(FEET) = 767.76 FLOW LENGTH(FEET) = 534.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 12.0 INCH PIPE IS 6.8 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.48
ESTIMATED PIPE DIAMETER(INCH) = 12.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 2.98
PIPE TRAVEL TIME(MIN.) = 1.37 Tc(MIN.) = 6.47
LONGEST FLOWPATH FROM NODE 5.10 TO NODE 6.40 = 905.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 6.40 IS CODE = 10
---------------------------------------------------------------------------- >>>>>MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK # 3 <<<<< ============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 6.40 IS CODE = 11
---------------------------------------------------------------------------- >>>>>CONFLUENCE MEMORY BANK # 1 WITH THE MAIN-STREAM MEMORY<<<<< ============================================================================ ** MAIN STREAM CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 2.98 6.47 1.952 0.25( 0.03) 0.10 1.5 6.10
2 2.32 11.27 1.420 0.25( 0.03) 0.10 1.7 5.10
LONGEST FLOWPATH FROM NODE 5.10 TO NODE 6.40 = 905.00 FEET. ** MEMORY BANK # 1 CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 17.21 6.69 1.915 0.25( 0.02) 0.10 8.6 3.10
2 17.46 7.23 1.832 0.25( 0.03) 0.10 9.2 2.10
3 17.63 9.14 1.602 0.25( 0.03) 0.10 10.9 1.10
4 17.56 9.35 1.581 0.25( 0.03) 0.10 11.0 4.10
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 6.40 = 1089.40 FEET. ** PEAK FLOW RATE TABLE **
Item: 11
1380
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 19.96 6.47 1.952 0.25( 0.02) 0.10 9.8 6.10
2 20.16 6.69 1.915 0.25( 0.02) 0.10 10.1 3.10
3 20.33 7.23 1.832 0.25( 0.03) 0.10 10.7 2.10
4 20.25 9.14 1.602 0.25( 0.03) 0.10 12.4 1.10
5 20.14 9.35 1.581 0.25( 0.03) 0.10 12.6 4.10
6 18.06 11.27 1.420 0.25( 0.03) 0.10 12.6 5.10
TOTAL AREA(ACRES) = 12.6
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 20.33 Tc(MIN.) = 7.229
EFFECTIVE AREA(ACRES) = 10.68 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 12.6
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 6.40 = 1089.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 7.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 767.66 DOWNSTREAM(FEET) = 766.79 FLOW LENGTH(FEET) = 134.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 27.0 INCH PIPE IS 18.9 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.85
ESTIMATED PIPE DIAMETER(INCH) = 27.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 20.33
PIPE TRAVEL TIME(MIN.) = 0.33 Tc(MIN.) = 7.56
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 7.40 = 1223.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 7.40 TO NODE 7.40 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 7.56
RAINFALL INTENSITY(INCH/HR) = 1.79
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 10.68
TOTAL STREAM AREA(ACRES) = 12.64
PEAK FLOW RATE(CFS) AT CONFLUENCE = 20.33
**************************************************************************** FLOW PROCESS FROM NODE 7.10 TO NODE 7.20 IS CODE = 21
Item: 11
1381
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 330.00
ELEVATION DATA: UPSTREAM(FEET) = 784.05 DOWNSTREAM(FEET) = 779.87 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 7.409
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.806
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 0.70 0.25 0.100 69 7.41
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 1.12
TOTAL AREA(ACRES) = 0.70 PEAK FLOW RATE(CFS) = 1.12
**************************************************************************** FLOW PROCESS FROM NODE 7.20 TO NODE 7.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 779.87 DOWNSTREAM(FEET) = 776.41 CHANNEL LENGTH THRU SUBAREA(FEET) = 323.00 CHANNEL SLOPE = 0.0107 CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 2 YEAR RAINFALL INTENSITY(INCH/HR) = 1.465
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 2.31 0.25 0.100 69
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 2.62
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 1.65 AVERAGE FLOW DEPTH(FEET) = 0.10 TRAVEL TIME(MIN.) = 3.26 Tc(MIN.) = 10.67
SUBAREA AREA(ACRES) = 2.31 SUBAREA RUNOFF(CFS) = 2.99
EFFECTIVE AREA(ACRES) = 3.01 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 3.0 PEAK FLOW RATE(CFS) = 3.90
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.12 FLOW VELOCITY(FEET/SEC.) = 1.80
LONGEST FLOWPATH FROM NODE 7.10 TO NODE 7.30 = 653.00 FEET. **************************************************************************** Item: 11
1382
FLOW PROCESS FROM NODE 7.30 TO NODE 7.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 773.00 DOWNSTREAM(FEET) = 771.55 FLOW LENGTH(FEET) = 145.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 8.5 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 5.40
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 3.90
PIPE TRAVEL TIME(MIN.) = 0.45 Tc(MIN.) = 11.12
LONGEST FLOWPATH FROM NODE 7.10 TO NODE 7.40 = 798.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 7.40 TO NODE 7.40 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 11.12
RAINFALL INTENSITY(INCH/HR) = 1.43
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 3.01
TOTAL STREAM AREA(ACRES) = 3.01
PEAK FLOW RATE(CFS) AT CONFLUENCE = 3.90
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 19.96 6.80 1.898 0.25( 0.02) 0.10 9.8 6.10
1 20.16 7.02 1.863 0.25( 0.02) 0.10 10.1 3.10
1 20.33 7.56 1.786 0.25( 0.03) 0.10 10.7 2.10
1 20.25 9.46 1.570 0.25( 0.03) 0.10 12.4 1.10
1 20.14 9.67 1.550 0.25( 0.03) 0.10 12.6 4.10
1 18.06 11.60 1.396 0.25( 0.03) 0.10 12.6 5.10
2 3.90 11.12 1.431 0.25( 0.03) 0.10 3.0 7.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 23.13 6.80 1.898 0.25( 0.02) 0.10 11.6 6.10
2 23.38 7.02 1.863 0.25( 0.02) 0.10 12.0 3.10
Item: 11
1383
3 23.65 7.56 1.786 0.25( 0.03) 0.10 12.7 2.10
4 23.89 9.46 1.570 0.25( 0.03) 0.10 15.0 1.10
5 23.82 9.67 1.550 0.25( 0.03) 0.10 15.2 4.10
6 22.48 11.12 1.431 0.25( 0.03) 0.10 15.6 7.10
7 21.86 11.60 1.396 0.25( 0.03) 0.10 15.6 5.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 23.89 Tc(MIN.) = 9.46
EFFECTIVE AREA(ACRES) = 15.00 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 15.6
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 7.40 = 1223.40 FEET. ============================================================================ END OF STUDY SUMMARY:

TOTAL AREA(ACRES) = 15.6 TC(MIN.) = 9.46
EFFECTIVE AREA(ACRES) = 15.00 AREA-AVERAGED Fm(INCH/HR)= 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.100 PEAK FLOW RATE(CFS) = 23.89
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 23.13 6.80 1.898 0.25( 0.02) 0.10 11.6 6.10
2 23.38 7.02 1.863 0.25( 0.02) 0.10 12.0 3.10
3 23.65 7.56 1.786 0.25( 0.03) 0.10 12.7 2.10
4 23.89 9.46 1.570 0.25( 0.03) 0.10 15.0 1.10
5 23.82 9.67 1.550 0.25( 0.03) 0.10 15.2 4.10
6 22.48 11.12 1.431 0.25( 0.03) 0.10 15.6 7.10
7 21.86 11.60 1.396 0.25( 0.03) 0.10 15.6 5.10
============================================================================ ============================================================================

END OF RATIONAL METHOD ANALYSIS

Item: 11
1384
____________________________________________________________________________ ****************************************************************************

RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
(Reference: 1986 ORANGE COUNTY HYDROLOGY CRITERION)
(c) Copyright 1983-2016 Advanced Engineering Software (aes) Ver. 23.0 Release Date: 07/01/2016 License ID 1499
Analysis prepared by:

************************** DESCRIPTION OF STUDY ************************** * COSTCO FOOTHILL RANCH *
* PROPOSED 100 YEAR RATIONAL METHOD *
* KIMLEY-HORN *
************************************************************************** FILE NAME: FRRM2YP.DAT
TIME/DATE OF STUDY: 10:46 09/18/2025
============================================================================ USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
============================================================================ --*TIME-OF-CONCENTRATION MODEL*--
USER SPECIFIED STORM EVENT(YEAR) = 100.00
SPECIFIED MINIMUM PIPE SIZE(INCH) = 6.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95 *DATA BANK RAINFALL USED*
*ANTECEDENT MOISTURE CONDITION (AMC) II ASSUMED FOR RATIONAL METHOD* *USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL* HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING

WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
=== ===== ========= ================= ====== ===== ====== ===== ======= 1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0312 0.167 0.0150 GLOBAL STREET FLOW-DEPTH CONSTRAINTS:

1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)

2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
*USER-SPECIFIED MINIMUM TOPOGRAPHIC SLOPE ADJUSTMENT NOT SELECTED **************************************************************************** FLOW PROCESS FROM NODE 1.10 TO NODE 1.20 IS CODE = 21
Item: 11
1385
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 330.00
ELEVATION DATA: UPSTREAM(FEET) = 785.09 DOWNSTREAM(FEET) = 780.16 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 7.168
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.033
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 2.72 0.25 0.100 69 7.17
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 12.26
TOTAL AREA(ACRES) = 2.72 PEAK FLOW RATE(CFS) = 12.26
**************************************************************************** FLOW PROCESS FROM NODE 1.20 TO NODE 2.20 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 775.54 DOWNSTREAM(FEET) = 774.90 FLOW LENGTH(FEET) = 128.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 24.0 INCH PIPE IS 16.0 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 5.50
ESTIMATED PIPE DIAMETER(INCH) = 24.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 12.26
PIPE TRAVEL TIME(MIN.) = 0.39 Tc(MIN.) = 7.56
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 2.20 = 458.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 2.20 TO NODE 2.20 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 7.56
RAINFALL INTENSITY(INCH/HR) = 4.88
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 2.72
TOTAL STREAM AREA(ACRES) = 2.72
PEAK FLOW RATE(CFS) AT CONFLUENCE = 12.26
Item: 11
1386
**************************************************************************** FLOW PROCESS FROM NODE 2.10 TO NODE 2.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 220.00
ELEVATION DATA: UPSTREAM(FEET) = 784.75 DOWNSTREAM(FEET) = 780.45 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.776
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.696
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 1.49 0.25 0.100 69 5.78
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 7.61
TOTAL AREA(ACRES) = 1.49 PEAK FLOW RATE(CFS) = 7.61
**************************************************************************** FLOW PROCESS FROM NODE 2.20 TO NODE 2.20 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 5.78
RAINFALL INTENSITY(INCH/HR) = 5.70
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 1.49
TOTAL STREAM AREA(ACRES) = 1.49
PEAK FLOW RATE(CFS) AT CONFLUENCE = 7.61
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 12.26 7.56 4.884 0.25( 0.03) 0.10 2.7 1.10
2 7.61 5.78 5.696 0.25( 0.03) 0.10 1.5 2.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
Item: 11
1387
1 18.54 5.78 5.696 0.25( 0.03) 0.10 3.6 2.10
2 18.78 7.56 4.884 0.25( 0.03) 0.10 4.2 1.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 18.78 Tc(MIN.) = 7.56
EFFECTIVE AREA(ACRES) = 4.21 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 4.2
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 2.20 = 458.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 2.30 TO NODE 3.30 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 774.80 DOWNSTREAM(FEET) = 773.75 FLOW LENGTH(FEET) = 136.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 24.0 INCH PIPE IS 19.0 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 7.03
ESTIMATED PIPE DIAMETER(INCH) = 24.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 18.78
PIPE TRAVEL TIME(MIN.) = 0.32 Tc(MIN.) = 7.88
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 3.30 = 594.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 3.30 TO NODE 3.30 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 7.88
RAINFALL INTENSITY(INCH/HR) = 4.77
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 4.21
TOTAL STREAM AREA(ACRES) = 4.21
PEAK FLOW RATE(CFS) AT CONFLUENCE = 18.78
**************************************************************************** FLOW PROCESS FROM NODE 3.10 TO NODE 3.20 IS CODE = 22
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>>>>USE SPECIFIED Tc VALUE FOR INITIAL SUBAREA<<<
============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 136.00
USER SPECIFIED Tc(MIN.) = 5.000
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 6.187
Item: 11
1388
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 2.31 0.25 0.100 69
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 12.81
TOTAL AREA(ACRES) = 2.31 PEAK FLOW RATE(CFS) = 12.81
**************************************************************************** FLOW PROCESS FROM NODE 3.20 TO NODE 3.30 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 778.22 DOWNSTREAM(FEET) = 773.75 FLOW LENGTH(FEET) = 265.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 18.0 INCH PIPE IS 14.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.57
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 12.81
PIPE TRAVEL TIME(MIN.) = 0.52 Tc(MIN.) = 5.52
LONGEST FLOWPATH FROM NODE 3.10 TO NODE 3.30 = 401.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 3.30 TO NODE 3.30 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 5.52
RAINFALL INTENSITY(INCH/HR) = 5.85
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 2.31
TOTAL STREAM AREA(ACRES) = 2.31
PEAK FLOW RATE(CFS) AT CONFLUENCE = 12.81
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 18.54 6.10 5.522 0.25( 0.03) 0.10 3.6 2.10
1 18.78 7.88 4.768 0.25( 0.03) 0.10 4.2 1.10
2 12.81 5.52 5.849 0.25( 0.03) 0.10 2.3 3.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.

Item: 11
1389
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 30.58 5.52 5.849 0.25( 0.03) 0.10 5.5 3.10
2 30.64 6.10 5.522 0.25( 0.03) 0.10 5.9 2.10
3 29.21 7.88 4.768 0.25( 0.03) 0.10 6.5 1.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 30.64 Tc(MIN.) = 6.10
EFFECTIVE AREA(ACRES) = 5.88 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 6.5
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 3.30 = 594.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 3.30 TO NODE 4.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 773.65 DOWNSTREAM(FEET) = 769.47 FLOW LENGTH(FEET) = 97.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 21.0 INCH PIPE IS 16.4 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 15.17
ESTIMATED PIPE DIAMETER(INCH) = 21.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 30.64
PIPE TRAVEL TIME(MIN.) = 0.11 Tc(MIN.) = 6.21
LONGEST FLOWPATH FROM NODE 1.10 TO NODE 4.40 = 691.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.40 TO NODE 4.40 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 6.21
RAINFALL INTENSITY(INCH/HR) = 5.47
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 5.88
TOTAL STREAM AREA(ACRES) = 6.52
PEAK FLOW RATE(CFS) AT CONFLUENCE = 30.64
**************************************************************************** FLOW PROCESS FROM NODE 4.10 TO NODE 4.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
Item: 11
1390
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 214.00
ELEVATION DATA: UPSTREAM(FEET) = 784.71 DOWNSTREAM(FEET) = 780.40 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 5.678
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.752
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 1.36 0.25 0.100 69 5.68
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 7.01
TOTAL AREA(ACRES) = 1.36 PEAK FLOW RATE(CFS) = 7.01
**************************************************************************** FLOW PROCESS FROM NODE 4.20 TO NODE 4.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 780.40 DOWNSTREAM(FEET) = 775.74 CHANNEL LENGTH THRU SUBAREA(FEET) = 237.00 CHANNEL SLOPE = 0.0197 CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 5.136
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 3.09 0.25 0.100 69
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 14.11
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 3.18 AVERAGE FLOW DEPTH(FEET) = 0.19 TRAVEL TIME(MIN.) = 1.24 Tc(MIN.) = 6.92
SUBAREA AREA(ACRES) = 3.09 SUBAREA RUNOFF(CFS) = 14.21
EFFECTIVE AREA(ACRES) = 4.45 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 4.4 PEAK FLOW RATE(CFS) = 20.47
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.22 FLOW VELOCITY(FEET/SEC.) = 3.36
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.30 = 451.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.30 TO NODE 4.40 IS CODE = 31
---------------------------------------------------------------------------- Item: 11
1391
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 771.14 DOWNSTREAM(FEET) = 769.66 FLOW LENGTH(FEET) = 296.40 MANNING'S N = 0.013
DEPTH OF FLOW IN 27.0 INCH PIPE IS 21.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.11
ESTIMATED PIPE DIAMETER(INCH) = 27.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 20.47
PIPE TRAVEL TIME(MIN.) = 0.81 Tc(MIN.) = 7.73
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.40 = 747.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.40 TO NODE 4.40 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 7.73
RAINFALL INTENSITY(INCH/HR) = 4.82
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 4.45
TOTAL STREAM AREA(ACRES) = 4.45
PEAK FLOW RATE(CFS) AT CONFLUENCE = 20.47
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 30.58 5.62 5.785 0.25( 0.03) 0.10 5.5 3.10
1 30.64 6.21 5.467 0.25( 0.03) 0.10 5.9 2.10
1 29.21 7.99 4.731 0.25( 0.03) 0.10 6.5 1.10
2 20.47 7.73 4.821 0.25( 0.03) 0.10 4.4 4.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 48.47 5.62 5.785 0.25( 0.03) 0.10 8.8 3.10
2 49.29 6.21 5.467 0.25( 0.03) 0.10 9.5 2.10
3 49.89 7.73 4.821 0.25( 0.03) 0.10 10.9 4.10
4 49.30 7.99 4.731 0.25( 0.03) 0.10 11.0 1.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 49.89 Tc(MIN.) = 7.73
Item: 11
1392
EFFECTIVE AREA(ACRES) = 10.88 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 11.0
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 4.40 = 747.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 4.40 TO NODE 6.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 769.66 DOWNSTREAM(FEET) = 767.76 FLOW LENGTH(FEET) = 342.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 39.0 INCH PIPE IS 27.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.09
ESTIMATED PIPE DIAMETER(INCH) = 39.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 49.89
PIPE TRAVEL TIME(MIN.) = 0.70 Tc(MIN.) = 8.43
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 6.40 = 1089.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 6.40 IS CODE = 10
---------------------------------------------------------------------------- >>>>>MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK # 1 <<<<< ============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 6.40 IS CODE = 13
---------------------------------------------------------------------------- >>>>>CLEAR THE MAIN-STREAM MEMORY<<<<<
============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 5.10 TO NODE 5.20 IS CODE = 21
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 229.00
ELEVATION DATA: UPSTREAM(FEET) = 784.59 DOWNSTREAM(FEET) = 784.09 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 9.099
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 4.390
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 0.41 0.25 0.100 69 9.10
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
Item: 11
1393
SUBAREA RUNOFF(CFS) = 1.61
TOTAL AREA(ACRES) = 0.41 PEAK FLOW RATE(CFS) = 1.61
**************************************************************************** FLOW PROCESS FROM NODE 5.20 TO NODE 6.30 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 779.49 DOWNSTREAM(FEET) = 778.11 FLOW LENGTH(FEET) = 142.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 12.0 INCH PIPE IS 5.8 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.30
ESTIMATED PIPE DIAMETER(INCH) = 12.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 1.61
PIPE TRAVEL TIME(MIN.) = 0.55 Tc(MIN.) = 9.65
LONGEST FLOWPATH FROM NODE 5.10 TO NODE 6.30 = 371.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.30 TO NODE 6.30 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 9.65
RAINFALL INTENSITY(INCH/HR) = 4.25
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 0.41
TOTAL STREAM AREA(ACRES) = 0.41
PEAK FLOW RATE(CFS) AT CONFLUENCE = 1.61
**************************************************************************** FLOW PROCESS FROM NODE 6.10 TO NODE 6.20 IS CODE = 22
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>>>>USE SPECIFIED Tc VALUE FOR INITIAL SUBAREA<<<
============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 142.00
USER SPECIFIED Tc(MIN.) = 5.000
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 6.187
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 1.26 0.25 0.100 69
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 6.99
Item: 11
1394
TOTAL AREA(ACRES) = 1.26 PEAK FLOW RATE(CFS) = 6.99
**************************************************************************** FLOW PROCESS FROM NODE 6.20 TO NODE 6.30 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 778.22 DOWNSTREAM(FEET) = 778.11 FLOW LENGTH(FEET) = 22.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 18.0 INCH PIPE IS 14.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.67
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 6.99
PIPE TRAVEL TIME(MIN.) = 0.08 Tc(MIN.) = 5.08
LONGEST FLOWPATH FROM NODE 6.10 TO NODE 6.30 = 164.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.30 TO NODE 6.30 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 5.08
RAINFALL INTENSITY(INCH/HR) = 6.13
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 1.26
TOTAL STREAM AREA(ACRES) = 1.26
PEAK FLOW RATE(CFS) AT CONFLUENCE = 6.99
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 1.61 9.65 4.245 0.25( 0.03) 0.10 0.4 5.10
2 6.99 5.08 6.132 0.25( 0.03) 0.10 1.3 6.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 8.21 5.08 6.132 0.25( 0.03) 0.10 1.5 6.10
2 6.44 9.65 4.245 0.25( 0.03) 0.10 1.7 5.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

Item: 11
1395
PEAK FLOW RATE(CFS) = 8.21 Tc(MIN.) = 5.08
EFFECTIVE AREA(ACRES) = 1.48 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 1.7
LONGEST FLOWPATH FROM NODE 5.10 TO NODE 6.30 = 371.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.30 TO NODE 6.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 778.11 DOWNSTREAM(FEET) = 767.76 FLOW LENGTH(FEET) = 534.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 11.5 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.11
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 8.21
PIPE TRAVEL TIME(MIN.) = 1.10 Tc(MIN.) = 6.18
LONGEST FLOWPATH FROM NODE 5.10 TO NODE 6.40 = 905.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 6.40 IS CODE = 10
---------------------------------------------------------------------------- >>>>>MAIN-STREAM MEMORY COPIED ONTO MEMORY BANK # 3 <<<<< ============================================================================ **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 6.40 IS CODE = 11
---------------------------------------------------------------------------- >>>>>CONFLUENCE MEMORY BANK # 1 WITH THE MAIN-STREAM MEMORY<<<<< ============================================================================ ** MAIN STREAM CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 8.21 6.18 5.482 0.25( 0.03) 0.10 1.5 6.10
2 6.44 10.79 3.982 0.25( 0.03) 0.10 1.7 5.10
LONGEST FLOWPATH FROM NODE 5.10 TO NODE 6.40 = 905.00 FEET. ** MEMORY BANK # 1 CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 48.47 6.33 5.405 0.25( 0.03) 0.10 8.8 3.10
2 49.29 6.91 5.140 0.25( 0.03) 0.10 9.5 2.10
3 49.89 8.43 4.586 0.25( 0.03) 0.10 10.9 4.10
4 49.30 8.69 4.507 0.25( 0.03) 0.10 11.0 1.10
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 6.40 = 1089.40 FEET. ** PEAK FLOW RATE TABLE **
Item: 11
1396
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 56.17 6.18 5.482 0.25( 0.03) 0.10 10.0 6.10
2 56.62 6.33 5.405 0.25( 0.03) 0.10 10.3 3.10
3 57.22 6.91 5.140 0.25( 0.03) 0.10 11.0 2.10
4 57.23 8.43 4.586 0.25( 0.03) 0.10 12.4 4.10
5 56.54 8.69 4.507 0.25( 0.03) 0.10 12.6 1.10
6 49.96 10.79 3.982 0.25( 0.03) 0.10 12.6 5.10
TOTAL AREA(ACRES) = 12.6
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 57.23 Tc(MIN.) = 8.433
EFFECTIVE AREA(ACRES) = 12.45 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 12.6
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 6.40 = 1089.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 6.40 TO NODE 7.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 767.66 DOWNSTREAM(FEET) = 766.79 FLOW LENGTH(FEET) = 134.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 39.0 INCH PIPE IS 28.5 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.82
ESTIMATED PIPE DIAMETER(INCH) = 39.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 57.23
PIPE TRAVEL TIME(MIN.) = 0.25 Tc(MIN.) = 8.69
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 7.40 = 1223.40 FEET. **************************************************************************** FLOW PROCESS FROM NODE 7.40 TO NODE 7.40 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:

TIME OF CONCENTRATION(MIN.) = 8.69
RAINFALL INTENSITY(INCH/HR) = 4.51
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 12.45
TOTAL STREAM AREA(ACRES) = 12.64
PEAK FLOW RATE(CFS) AT CONFLUENCE = 57.23
**************************************************************************** FLOW PROCESS FROM NODE 7.10 TO NODE 7.20 IS CODE = 21
Item: 11
1397
---------------------------------------------------------------------------- >>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
>>USE TIME-OF-CONCENTRATION NOMOGRAPH FOR INITIAL SUBAREA<< ============================================================================ INITIAL SUBAREA FLOW-LENGTH(FEET) = 330.00
ELEVATION DATA: UPSTREAM(FEET) = 784.05 DOWNSTREAM(FEET) = 779.87 Tc = K*[(LENGTH** 3.00)/(ELEVATION CHANGE)]**0.20
SUBAREA ANALYSIS USED MINIMUM Tc(MIN.) = 7.409
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 4.939
SUBAREA Tc AND LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS Tc
LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN (MIN.)
COMMERCIAL C 0.70 0.25 0.100 69 7.41
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
SUBAREA RUNOFF(CFS) = 3.10
TOTAL AREA(ACRES) = 0.70 PEAK FLOW RATE(CFS) = 3.10
**************************************************************************** FLOW PROCESS FROM NODE 7.20 TO NODE 7.30 IS CODE = 51
---------------------------------------------------------------------------- >>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 779.87 DOWNSTREAM(FEET) = 776.41 CHANNEL LENGTH THRU SUBAREA(FEET) = 323.00 CHANNEL SLOPE = 0.0107 CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 99.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
* 100 YEAR RAINFALL INTENSITY(INCH/HR) = 4.168
SUBAREA LOSS RATE DATA(AMC II):

DEVELOPMENT TYPE/ SCS SOIL AREA Fp Ap SCS

LAND USE GROUP (ACRES) (INCH/HR) (DECIMAL) CN
COMMERCIAL C 2.31 0.25 0.100 69
SUBAREA AVERAGE PERVIOUS LOSS RATE, Fp(INCH/HR) = 0.25
SUBAREA AVERAGE PERVIOUS AREA FRACTION, Ap = 0.100
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 7.42
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 2.11 AVERAGE FLOW DEPTH(FEET) = 0.16 TRAVEL TIME(MIN.) = 2.56 Tc(MIN.) = 9.96
SUBAREA AREA(ACRES) = 2.31 SUBAREA RUNOFF(CFS) = 8.61
EFFECTIVE AREA(ACRES) = 3.01 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 3.0 PEAK FLOW RATE(CFS) = 11.22
END OF SUBAREA CHANNEL FLOW HYDRAULICS:

DEPTH(FEET) = 0.20 FLOW VELOCITY(FEET/SEC.) = 2.36
LONGEST FLOWPATH FROM NODE 7.10 TO NODE 7.30 = 653.00 FEET. **************************************************************************** Item: 11
1398
FLOW PROCESS FROM NODE 7.30 TO NODE 7.40 IS CODE = 31
---------------------------------------------------------------------------- >>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<< ============================================================================ ELEVATION DATA: UPSTREAM(FEET) = 773.00 DOWNSTREAM(FEET) = 771.55 FLOW LENGTH(FEET) = 145.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 21.0 INCH PIPE IS 13.3 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 7.00
ESTIMATED PIPE DIAMETER(INCH) = 21.00 NUMBER OF PIPES = 1 PIPE-FLOW(CFS) = 11.22
PIPE TRAVEL TIME(MIN.) = 0.35 Tc(MIN.) = 10.31
LONGEST FLOWPATH FROM NODE 7.10 TO NODE 7.40 = 798.00 FEET. **************************************************************************** FLOW PROCESS FROM NODE 7.40 TO NODE 7.40 IS CODE = 1
---------------------------------------------------------------------------- >>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<< ============================================================================ TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:

TIME OF CONCENTRATION(MIN.) = 10.31
RAINFALL INTENSITY(INCH/HR) = 4.09
AREA-AVERAGED Fm(INCH/HR) = 0.03
AREA-AVERAGED Fp(INCH/HR) = 0.25
AREA-AVERAGED Ap = 0.10
EFFECTIVE STREAM AREA(ACRES) = 3.01
TOTAL STREAM AREA(ACRES) = 3.01
PEAK FLOW RATE(CFS) AT CONFLUENCE = 11.22
** CONFLUENCE DATA **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 56.17 6.43 5.357 0.25( 0.03) 0.10 10.0 6.10
1 56.62 6.58 5.285 0.25( 0.03) 0.10 10.3 3.10
1 57.22 7.16 5.035 0.25( 0.03) 0.10 11.0 2.10
1 57.23 8.69 4.509 0.25( 0.03) 0.10 12.4 4.10
1 56.54 8.95 4.433 0.25( 0.03) 0.10 12.6 1.10
1 49.96 11.05 3.927 0.25( 0.03) 0.10 12.6 5.10
2 11.22 10.31 4.087 0.25( 0.03) 0.10 3.0 7.10

RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 65.36 6.43 5.357 0.25( 0.03) 0.10 11.9 6.10
2 65.90 6.58 5.285 0.25( 0.03) 0.10 12.2 3.10
Item: 11
1399
3 66.84 7.16 5.035 0.25( 0.03) 0.10 13.1 2.10
4 67.67 8.69 4.509 0.25( 0.03) 0.10 15.0 4.10
5 67.11 8.95 4.433 0.25( 0.03) 0.10 15.2 1.10
6 63.51 10.31 4.087 0.25( 0.03) 0.10 15.6 7.10
7 60.74 11.05 3.927 0.25( 0.03) 0.10 15.6 5.10
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:

PEAK FLOW RATE(CFS) = 67.67 Tc(MIN.) = 8.69
EFFECTIVE AREA(ACRES) = 14.98 AREA-AVERAGED Fm(INCH/HR) = 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.10 TOTAL AREA(ACRES) = 15.6
LONGEST FLOWPATH FROM NODE 4.10 TO NODE 7.40 = 1223.40 FEET. ============================================================================ END OF STUDY SUMMARY:

TOTAL AREA(ACRES) = 15.6 TC(MIN.) = 8.69
EFFECTIVE AREA(ACRES) = 14.98 AREA-AVERAGED Fm(INCH/HR)= 0.03 AREA-AVERAGED Fp(INCH/HR) = 0.25 AREA-AVERAGED Ap = 0.100 PEAK FLOW RATE(CFS) = 67.67
** PEAK FLOW RATE TABLE **
STREAM Q Tc Intensity Fp(Fm) Ap Ae HEADWATER
NUMBER (CFS) (MIN.) (INCH/HR) (INCH/HR) (ACRES) NODE
1 65.36 6.43 5.357 0.25( 0.03) 0.10 11.9 6.10
2 65.90 6.58 5.285 0.25( 0.03) 0.10 12.2 3.10
3 66.84 7.16 5.035 0.25( 0.03) 0.10 13.1 2.10
4 67.67 8.69 4.509 0.25( 0.03) 0.10 15.0 4.10
5 67.11 8.95 4.433 0.25( 0.03) 0.10 15.2 1.10
6 63.51 10.31 4.087 0.25( 0.03) 0.10 15.6 7.10
7 60.74 11.05 3.927 0.25( 0.03) 0.10 15.6 5.10
============================================================================ ============================================================================

END OF RATIONAL METHOD ANALYSIS

Item: 11
1400
14 Costco Foothill Ranch Preliminary Hydrology Report
November 2025
Appendix F - Unit Hydrograph Analysis
Item: 11
1401
____________________________________________________________________________ ****************************************************************************

SMALL AREA UNIT HYDROGRAPH MODEL
============================================================================ (C) Copyright 1989-2016 Advanced Engineering Software (aes) Ver. 23.0 Release Date: 07/01/2016 License ID 1499
Analysis prepared by:

**************************************************************************** ---------------------------------------------------------------------------- Problem Descriptions:

COSTCO FOOTHILL RANCH
EXISTING DA A 2 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 1.45
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.250
TIME OF CONCENTRATION(MIN.) = 6.40

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 2
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.19
30-MINUTE POINT RAINFALL VALUE(INCHES) = 0.40
1-HOUR POINT RAINFALL VALUE(INCHES) = 0.53
3-HOUR POINT RAINFALL VALUE(INCHES) = 0.89
6-HOUR POINT RAINFALL VALUE(INCHES) = 1.22
24-HOUR POINT RAINFALL VALUE(INCHES) = 2.05
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 0.22
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.03
**************************************************************************** TIME VOLUME Q 0. 2.5 5.0 7.5 10.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.11 0.0002 0.04 Q . . . .

0.21 0.0006 0.04 Q . . . .

Item: 11
1402

0.32 0.0009 0.04 Q . . . .

0.43 0.0013 0.04 Q . . . .

0.53 0.0017 0.04 Q . . . .

0.64 0.0020 0.04 Q . . . .

0.75 0.0024 0.04 Q . . . .

0.85 0.0028 0.04 Q . . . .

0.96 0.0032 0.04 Q . . . .

1.07 0.0036 0.04 Q . . . .

1.17 0.0039 0.04 Q . . . .

1.28 0.0043 0.04 Q . . . .

1.39 0.0047 0.04 Q . . . .

1.49 0.0051 0.04 Q . . . .

1.60 0.0055 0.04 Q . . . .

1.71 0.0059 0.04 Q . . . .

1.81 0.0063 0.04 Q . . . .

1.92 0.0067 0.04 Q . . . .

2.03 0.0071 0.05 Q . . . .

2.13 0.0075 0.05 Q . . . .

2.24 0.0079 0.05 Q . . . .

2.35 0.0083 0.05 Q . . . .

2.45 0.0087 0.05 Q . . . .

2.56 0.0091 0.05 Q . . . .

2.67 0.0095 0.05 Q . . . .

2.77 0.0099 0.05 Q . . . .

2.88 0.0103 0.05 Q . . . .

2.99 0.0107 0.05 Q . . . .

3.09 0.0112 0.05 Q . . . .

3.20 0.0116 0.05 Q . . . .

3.31 0.0120 0.05 Q . . . .

3.41 0.0124 0.05 Q . . . .

3.52 0.0129 0.05 Q . . . .

3.63 0.0133 0.05 Q . . . .

3.73 0.0137 0.05 Q . . . .

3.84 0.0142 0.05 Q . . . .

3.95 0.0146 0.05 Q . . . .

4.05 0.0150 0.05 Q . . . .

4.16 0.0155 0.05 Q . . . .

4.27 0.0159 0.05 Q . . . .

4.37 0.0164 0.05 Q . . . .

4.48 0.0168 0.05 Q . . . .

4.59 0.0173 0.05 Q . . . .

4.69 0.0177 0.05 Q . . . .

4.80 0.0182 0.05 Q . . . .

4.91 0.0186 0.05 Q . . . .

5.01 0.0191 0.05 Q . . . .

5.12 0.0196 0.05 Q . . . .

5.23 0.0200 0.05 Q . . . .

5.33 0.0205 0.05 Q . . . .

5.44 0.0210 0.05 Q . . . .

5.55 0.0214 0.05 Q . . . .

Item: 11
1403

5.65 0.0219 0.05 Q . . . .

5.76 0.0224 0.05 Q . . . .

5.87 0.0229 0.06 Q . . . .

5.97 0.0234 0.06 Q . . . .

6.08 0.0239 0.06 Q . . . .

6.19 0.0244 0.06 Q . . . .

6.29 0.0249 0.06 Q . . . .

6.40 0.0254 0.06 Q . . . .

6.51 0.0259 0.06 Q . . . .

6.61 0.0264 0.06 Q . . . .

6.72 0.0269 0.06 Q . . . .

6.83 0.0274 0.06 Q . . . .

6.93 0.0279 0.06 Q . . . .

7.04 0.0284 0.06 Q . . . .

7.15 0.0290 0.06 Q . . . .

7.25 0.0295 0.06 Q . . . .

7.36 0.0300 0.06 Q . . . .

7.47 0.0306 0.06 Q . . . .

7.57 0.0311 0.06 Q . . . .

7.68 0.0317 0.06 Q . . . .

7.79 0.0322 0.06 Q . . . .

7.89 0.0328 0.06 Q . . . .

8.00 0.0333 0.06 Q . . . .

8.11 0.0339 0.06 Q . . . .

8.21 0.0345 0.07 Q . . . .

8.32 0.0351 0.07 Q . . . .

8.43 0.0356 0.07 Q . . . .

8.53 0.0362 0.07 Q . . . .

8.64 0.0368 0.07 Q . . . .

8.75 0.0374 0.07 Q . . . .

8.85 0.0380 0.07 Q . . . .

8.96 0.0386 0.07 Q . . . .

9.07 0.0392 0.07 Q . . . .

9.17 0.0398 0.07 Q . . . .

9.28 0.0405 0.07 Q . . . .

9.39 0.0411 0.07 Q . . . .

9.49 0.0417 0.07 Q . . . .

9.60 0.0424 0.07 Q . . . .

9.71 0.0430 0.07 Q . . . .

9.81 0.0437 0.07 Q . . . .

9.92 0.0444 0.08 Q . . . .

10.03 0.0450 0.08 Q . . . .

10.13 0.0457 0.08 Q . . . .

10.24 0.0464 0.08 Q . . . .

10.35 0.0471 0.08 Q . . . .

10.45 0.0478 0.08 Q . . . .

10.56 0.0485 0.08 Q . . . .

10.67 0.0492 0.08 Q . . . .

10.77 0.0499 0.08 Q . . . .

10.88 0.0507 0.08 Q . . . .

Item: 11
1404

10.99 0.0514 0.09 Q . . . .

11.09 0.0522 0.09 Q . . . .

11.20 0.0530 0.09 Q . . . .

11.31 0.0537 0.09 Q . . . .

11.41 0.0545 0.09 Q . . . .

11.52 0.0553 0.09 Q . . . .

11.63 0.0561 0.09 Q . . . .

11.73 0.0570 0.09 Q . . . .

11.84 0.0578 0.10 Q . . . .

11.95 0.0586 0.10 Q . . . .

12.05 0.0595 0.10 Q . . . .

12.16 0.0605 0.12 Q . . . .

12.27 0.0616 0.12 Q . . . .

12.37 0.0627 0.13 Q . . . .

12.48 0.0638 0.13 Q . . . .

12.59 0.0650 0.13 Q . . . .

12.69 0.0661 0.13 Q . . . .

12.80 0.0673 0.13 Q . . . .

12.91 0.0685 0.14 Q . . . .

13.01 0.0697 0.14 Q . . . .

13.12 0.0709 0.14 Q . . . .

13.23 0.0722 0.14 Q . . . .

13.33 0.0735 0.15 Q . . . .

13.44 0.0748 0.15 Q . . . .

13.55 0.0762 0.16 Q . . . .

13.65 0.0775 0.16 Q . . . .

13.76 0.0790 0.16 Q . . . .

13.87 0.0804 0.17 Q . . . .

13.97 0.0819 0.17 Q . . . .

14.08 0.0834 0.18 Q . . . .

14.19 0.0850 0.19 Q . . . .

14.29 0.0867 0.19 Q . . . .

14.40 0.0884 0.20 Q . . . .

14.51 0.0902 0.21 Q . . . .

14.61 0.0921 0.22 Q . . . .

14.72 0.0940 0.22 Q . . . .

14.83 0.0960 0.23 Q . . . .

14.93 0.0981 0.24 Q . . . .

15.04 0.1003 0.26 .Q . . . .

15.15 0.1027 0.27 .Q . . . .

15.25 0.1051 0.29 .Q . . . .

15.36 0.1078 0.31 .Q . . . .

15.47 0.1105 0.30 .Q . . . .

15.57 0.1132 0.32 .Q . . . .

15.68 0.1163 0.39 .Q . . . .

15.79 0.1200 0.44 .Q . . . .

15.89 0.1247 0.63 . Q . . . .

16.00 0.1312 0.86 . Q . . . .

16.11 0.1464 2.58 . Q . . .

16.21 0.1600 0.52 . Q . . . .

Item: 11
1405

16.32 0.1638 0.35 .Q . . . .

16.43 0.1667 0.31 .Q . . . .

16.53 0.1693 0.28 .Q . . . .

16.64 0.1717 0.25 .Q . . . .

16.75 0.1738 0.23 Q . . . .

16.85 0.1757 0.21 Q . . . .

16.96 0.1775 0.20 Q . . . .

17.07 0.1792 0.18 Q . . . .

17.17 0.1807 0.17 Q . . . .

17.28 0.1822 0.16 Q . . . .

17.39 0.1836 0.15 Q . . . .

17.49 0.1849 0.15 Q . . . .

17.60 0.1861 0.14 Q . . . .

17.71 0.1874 0.14 Q . . . .

17.81 0.1885 0.13 Q . . . .

17.92 0.1897 0.13 Q . . . .

18.03 0.1908 0.12 Q . . . .

18.13 0.1917 0.10 Q . . . .

18.24 0.1926 0.09 Q . . . .

18.35 0.1934 0.09 Q . . . .

18.45 0.1942 0.09 Q . . . .

18.56 0.1950 0.09 Q . . . .

18.67 0.1957 0.08 Q . . . .

18.77 0.1965 0.08 Q . . . .

18.88 0.1972 0.08 Q . . . .

18.99 0.1979 0.08 Q . . . .

19.09 0.1986 0.08 Q . . . .

19.20 0.1993 0.08 Q . . . .

19.31 0.1999 0.07 Q . . . .

19.41 0.2006 0.07 Q . . . .

19.52 0.2012 0.07 Q . . . .

19.63 0.2018 0.07 Q . . . .

19.73 0.2024 0.07 Q . . . .

19.84 0.2030 0.07 Q . . . .

19.95 0.2036 0.07 Q . . . .

20.05 0.2042 0.06 Q . . . .

20.16 0.2047 0.06 Q . . . .

20.27 0.2053 0.06 Q . . . .

20.37 0.2059 0.06 Q . . . .

20.48 0.2064 0.06 Q . . . .

20.59 0.2069 0.06 Q . . . .

20.69 0.2074 0.06 Q . . . .

20.80 0.2080 0.06 Q . . . .

20.91 0.2085 0.06 Q . . . .

21.01 0.2090 0.06 Q . . . .

21.12 0.2095 0.06 Q . . . .

21.23 0.2100 0.06 Q . . . .

21.33 0.2104 0.05 Q . . . .

21.44 0.2109 0.05 Q . . . .

21.55 0.2114 0.05 Q . . . .

Item: 11
1406

21.65 0.2119 0.05 Q . . . .

21.76 0.2123 0.05 Q . . . .

21.87 0.2128 0.05 Q . . . .

21.97 0.2132 0.05 Q . . . .

22.08 0.2137 0.05 Q . . . .

22.19 0.2141 0.05 Q . . . .

22.29 0.2145 0.05 Q . . . .

22.40 0.2150 0.05 Q . . . .

22.51 0.2154 0.05 Q . . . .

22.61 0.2158 0.05 Q . . . .

22.72 0.2162 0.05 Q . . . .

22.83 0.2166 0.05 Q . . . .

22.93 0.2170 0.05 Q . . . .

23.04 0.2174 0.05 Q . . . .

23.15 0.2178 0.05 Q . . . .

23.25 0.2182 0.04 Q . . . .

23.36 0.2186 0.04 Q . . . .

23.47 0.2190 0.04 Q . . . .

23.57 0.2194 0.04 Q . . . .

23.68 0.2198 0.04 Q . . . .

23.79 0.2202 0.04 Q . . . .

23.89 0.2205 0.04 Q . . . .

24.00 0.2209 0.04 Q . . . .

24.11 0.2211 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1440.0
10% 96.0
20% 25.6
30% 12.8
40% 6.4
50% 6.4
60% 6.4
70% 6.4
80% 6.4
90% 6.4
Item: 11
1407
____________________________________________________________________________ ****************************************************************************

SMALL AREA UNIT HYDROGRAPH MODEL
============================================================================ (C) Copyright 1989-2016 Advanced Engineering Software (aes) Ver. 23.0 Release Date: 07/01/2016 License ID 1499
Analysis prepared by:

**************************************************************************** ---------------------------------------------------------------------------- Problem Descriptions:

COSTCO FOOTHILL RANCH
EXISTING DA B 2 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 6.28
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.131
TIME OF CONCENTRATION(MIN.) = 8.82

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 2
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.19
30-MINUTE POINT RAINFALL VALUE(INCHES) = 0.40
1-HOUR POINT RAINFALL VALUE(INCHES) = 0.53
3-HOUR POINT RAINFALL VALUE(INCHES) = 0.89
6-HOUR POINT RAINFALL VALUE(INCHES) = 1.22
24-HOUR POINT RAINFALL VALUE(INCHES) = 2.05
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 0.96
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.11
**************************************************************************** TIME VOLUME Q 0. 2.5 5.0 7.5 10.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.12 0.0011 0.18 Q . . . .

0.27 0.0033 0.18 Q . . . .

Item: 11
1408

0.42 0.0055 0.18 Q . . . .

0.57 0.0077 0.18 Q . . . .

0.71 0.0100 0.18 Q . . . .

0.86 0.0122 0.19 Q . . . .

1.01 0.0145 0.19 Q . . . .

1.15 0.0168 0.19 Q . . . .

1.30 0.0191 0.19 Q . . . .

1.45 0.0214 0.19 Q . . . .

1.59 0.0237 0.19 Q . . . .

1.74 0.0261 0.19 Q . . . .

1.89 0.0284 0.19 Q . . . .

2.04 0.0308 0.20 Q . . . .

2.18 0.0332 0.20 Q . . . .

2.33 0.0356 0.20 Q . . . .

2.48 0.0380 0.20 Q . . . .

2.62 0.0404 0.20 Q . . . .

2.77 0.0429 0.20 Q . . . .

2.92 0.0453 0.20 Q . . . .

3.06 0.0478 0.20 Q . . . .

3.21 0.0503 0.21 Q . . . .

3.36 0.0529 0.21 Q . . . .

3.51 0.0554 0.21 Q . . . .

3.65 0.0579 0.21 Q . . . .

3.80 0.0605 0.21 Q . . . .

3.95 0.0631 0.21 Q . . . .

4.09 0.0657 0.22 Q . . . .

4.24 0.0684 0.22 Q . . . .

4.39 0.0710 0.22 Q . . . .

4.53 0.0737 0.22 Q . . . .

4.68 0.0764 0.22 Q . . . .

4.83 0.0791 0.22 Q . . . .

4.98 0.0819 0.23 Q . . . .

5.12 0.0846 0.23 Q . . . .

5.27 0.0874 0.23 Q . . . .

5.42 0.0902 0.23 Q . . . .

5.56 0.0931 0.23 Q . . . .

5.71 0.0959 0.24 Q . . . .

5.86 0.0988 0.24 Q . . . .

6.00 0.1017 0.24 Q . . . .

6.15 0.1046 0.24 Q . . . .

6.30 0.1076 0.24 Q . . . .

6.45 0.1106 0.25 Q . . . .

6.59 0.1136 0.25 Q . . . .

6.74 0.1167 0.25 .Q . . . .

6.89 0.1198 0.25 .Q . . . .

7.03 0.1229 0.26 .Q . . . .

7.18 0.1260 0.26 .Q . . . .

7.33 0.1292 0.26 .Q . . . .

7.47 0.1324 0.27 .Q . . . .

7.62 0.1356 0.27 .Q . . . .

Item: 11
1409

7.77 0.1389 0.27 .Q . . . .

7.92 0.1422 0.27 .Q . . . .

8.06 0.1456 0.28 .Q . . . .

8.21 0.1490 0.28 .Q . . . .

8.36 0.1524 0.28 .Q . . . .

8.50 0.1559 0.29 .Q . . . .

8.65 0.1594 0.29 .Q . . . .

8.80 0.1630 0.30 .Q . . . .

8.94 0.1666 0.30 .Q . . . .

9.09 0.1702 0.30 .Q . . . .

9.24 0.1739 0.31 .Q . . . .

9.39 0.1777 0.31 .Q . . . .

9.53 0.1815 0.31 .Q . . . .

9.68 0.1853 0.32 .Q . . . .

9.83 0.1892 0.32 .Q . . . .

9.97 0.1932 0.33 .Q . . . .

10.12 0.1972 0.33 .Q . . . .

10.27 0.2013 0.34 .Q . . . .

10.41 0.2054 0.34 .Q . . . .

10.56 0.2097 0.35 .Q . . . .

10.71 0.2139 0.35 .Q . . . .

10.85 0.2183 0.36 .Q . . . .

11.00 0.2228 0.37 .Q . . . .

11.15 0.2273 0.38 .Q . . . .

11.30 0.2319 0.38 .Q . . . .

11.44 0.2366 0.39 .Q . . . .

11.59 0.2414 0.40 .Q . . . .

11.74 0.2462 0.41 .Q . . . .

11.88 0.2512 0.41 .Q . . . .

12.03 0.2563 0.43 .Q . . . .

12.18 0.2620 0.51 . Q . . . .

12.32 0.2684 0.54 . Q . . . .

12.47 0.2750 0.55 . Q . . . .

12.62 0.2817 0.56 . Q . . . .

12.77 0.2886 0.57 . Q . . . .

12.91 0.2957 0.59 . Q . . . .

13.06 0.3030 0.60 . Q . . . .

13.21 0.3104 0.62 . Q . . . .

13.35 0.3181 0.64 . Q . . . .

13.50 0.3260 0.66 . Q . . . .

13.65 0.3341 0.68 . Q . . . .

13.80 0.3425 0.71 . Q . . . .

13.94 0.3512 0.72 . Q . . . .

14.09 0.3602 0.77 . Q . . . .

14.24 0.3699 0.81 . Q . . . .

14.38 0.3800 0.86 . Q . . . .

14.53 0.3906 0.89 . Q . . . .

14.68 0.4017 0.95 . Q . . . .

14.82 0.4135 0.98 . Q . . . .

14.97 0.4259 1.07 . Q . . . .

Item: 11
1410

15.12 0.4393 1.12 . Q . . . .

15.27 0.4537 1.26 . Q . . . .

15.41 0.4695 1.34 . Q . . . .

15.56 0.4861 1.38 . Q . . . .

15.71 0.5039 1.56 . Q . . . .

15.85 0.5272 2.26 . Q. . . .

16.00 0.5597 3.09 . . Q . . .

16.15 0.6346 9.25 . . . . Q .

16.29 0.7019 1.83 . Q . . . .

16.44 0.7208 1.29 . Q . . . .

16.59 0.7358 1.19 . Q . . . .

16.73 0.7493 1.03 . Q . . . .

16.88 0.7610 0.91 . Q . . . .

17.03 0.7717 0.83 . Q . . . .

17.18 0.7812 0.74 . Q . . . .

17.32 0.7899 0.69 . Q . . . .

17.47 0.7981 0.65 . Q . . . .

17.62 0.8057 0.61 . Q . . . .

17.76 0.8130 0.58 . Q . . . .

17.91 0.8199 0.56 . Q . . . .

18.06 0.8265 0.53 . Q . . . .

18.20 0.8323 0.42 .Q . . . .

18.35 0.8373 0.40 .Q . . . .

18.50 0.8421 0.39 .Q . . . .

18.65 0.8467 0.37 .Q . . . .

18.79 0.8511 0.36 .Q . . . .

18.94 0.8554 0.35 .Q . . . .

19.09 0.8596 0.34 .Q . . . .

19.23 0.8636 0.33 .Q . . . .

19.38 0.8675 0.32 .Q . . . .

19.53 0.8713 0.31 .Q . . . .

19.67 0.8750 0.30 .Q . . . .

19.82 0.8786 0.29 .Q . . . .

19.97 0.8821 0.29 .Q . . . .

20.12 0.8855 0.28 .Q . . . .

20.26 0.8889 0.27 .Q . . . .

20.41 0.8922 0.27 .Q . . . .

20.56 0.8954 0.26 .Q . . . .

20.70 0.8985 0.26 .Q . . . .

20.85 0.9016 0.25 .Q . . . .

21.00 0.9046 0.25 Q . . . .

21.14 0.9076 0.24 Q . . . .

21.29 0.9105 0.24 Q . . . .

21.44 0.9134 0.23 Q . . . .

21.59 0.9162 0.23 Q . . . .

21.73 0.9189 0.23 Q . . . .

21.88 0.9217 0.22 Q . . . .

22.03 0.9243 0.22 Q . . . .

22.17 0.9270 0.22 Q . . . .

22.32 0.9296 0.21 Q . . . .

Item: 11
1411

22.47 0.9321 0.21 Q . . . .

22.61 0.9346 0.21 Q . . . .

22.76 0.9371 0.20 Q . . . .

22.91 0.9396 0.20 Q . . . .

23.06 0.9420 0.20 Q . . . .

23.20 0.9444 0.20 Q . . . .

23.35 0.9467 0.19 Q . . . .

23.50 0.9491 0.19 Q . . . .

23.64 0.9514 0.19 Q . . . .

23.79 0.9536 0.19 Q . . . .

23.94 0.9559 0.18 Q . . . .

24.08 0.9581 0.18 Q . . . .

24.23 0.9592 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1446.5
10% 132.3
20% 26.5
30% 17.6
40% 8.8
50% 8.8
60% 8.8
70% 8.8
80% 8.8
90% 8.8
Item: 11
1412
____________________________________________________________________________ ****************************************************************************

SMALL AREA UNIT HYDROGRAPH MODEL
============================================================================ (C) Copyright 1989-2016 Advanced Engineering Software (aes) Ver. 23.0 Release Date: 07/01/2016 License ID 1499
Analysis prepared by:

**************************************************************************** ---------------------------------------------------------------------------- Problem Descriptions:

COSTCO FOOTHILL RANCH
EXISTING DA C 2YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 3.48
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.131
TIME OF CONCENTRATION(MIN.) = 7.39

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 2
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.19
30-MINUTE POINT RAINFALL VALUE(INCHES) = 0.40
1-HOUR POINT RAINFALL VALUE(INCHES) = 0.53
3-HOUR POINT RAINFALL VALUE(INCHES) = 0.89
6-HOUR POINT RAINFALL VALUE(INCHES) = 1.22
24-HOUR POINT RAINFALL VALUE(INCHES) = 2.05
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 0.53
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.06
**************************************************************************** TIME VOLUME Q 0. 2.5 5.0 7.5 10.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.11 0.0005 0.10 Q . . . .

0.23 0.0015 0.10 Q . . . .

Item: 11
1413

0.36 0.0025 0.10 Q . . . .

0.48 0.0035 0.10 Q . . . .

0.60 0.0046 0.10 Q . . . .

0.73 0.0056 0.10 Q . . . .

0.85 0.0067 0.10 Q . . . .

0.97 0.0077 0.10 Q . . . .

1.10 0.0088 0.10 Q . . . .

1.22 0.0098 0.10 Q . . . .

1.34 0.0109 0.11 Q . . . .

1.47 0.0120 0.11 Q . . . .

1.59 0.0131 0.11 Q . . . .

1.71 0.0142 0.11 Q . . . .

1.84 0.0153 0.11 Q . . . .

1.96 0.0164 0.11 Q . . . .

2.08 0.0175 0.11 Q . . . .

2.21 0.0186 0.11 Q . . . .

2.33 0.0197 0.11 Q . . . .

2.45 0.0208 0.11 Q . . . .

2.57 0.0219 0.11 Q . . . .

2.70 0.0231 0.11 Q . . . .

2.82 0.0242 0.11 Q . . . .

2.94 0.0254 0.11 Q . . . .

3.07 0.0265 0.11 Q . . . .

3.19 0.0277 0.11 Q . . . .

3.31 0.0288 0.12 Q . . . .

3.44 0.0300 0.12 Q . . . .

3.56 0.0312 0.12 Q . . . .

3.68 0.0324 0.12 Q . . . .

3.81 0.0336 0.12 Q . . . .

3.93 0.0348 0.12 Q . . . .

4.05 0.0360 0.12 Q . . . .

4.18 0.0372 0.12 Q . . . .

4.30 0.0385 0.12 Q . . . .

4.42 0.0397 0.12 Q . . . .

4.55 0.0409 0.12 Q . . . .

4.67 0.0422 0.12 Q . . . .

4.79 0.0435 0.12 Q . . . .

4.92 0.0447 0.13 Q . . . .

5.04 0.0460 0.13 Q . . . .

5.16 0.0473 0.13 Q . . . .

5.28 0.0486 0.13 Q . . . .

5.41 0.0499 0.13 Q . . . .

5.53 0.0512 0.13 Q . . . .

5.65 0.0526 0.13 Q . . . .

5.78 0.0539 0.13 Q . . . .

5.90 0.0552 0.13 Q . . . .

6.02 0.0566 0.13 Q . . . .

6.15 0.0580 0.13 Q . . . .

6.27 0.0593 0.14 Q . . . .

6.39 0.0607 0.14 Q . . . .

Item: 11
1414

6.52 0.0621 0.14 Q . . . .

6.64 0.0635 0.14 Q . . . .

6.76 0.0650 0.14 Q . . . .

6.89 0.0664 0.14 Q . . . .

7.01 0.0678 0.14 Q . . . .

7.13 0.0693 0.14 Q . . . .

7.26 0.0708 0.15 Q . . . .

7.38 0.0722 0.15 Q . . . .

7.50 0.0737 0.15 Q . . . .

7.62 0.0752 0.15 Q . . . .

7.75 0.0768 0.15 Q . . . .

7.87 0.0783 0.15 Q . . . .

7.99 0.0799 0.15 Q . . . .

8.12 0.0814 0.15 Q . . . .

8.24 0.0830 0.16 Q . . . .

8.36 0.0846 0.16 Q . . . .

8.49 0.0862 0.16 Q . . . .

8.61 0.0879 0.16 Q . . . .

8.73 0.0895 0.16 Q . . . .

8.86 0.0912 0.16 Q . . . .

8.98 0.0929 0.17 Q . . . .

9.10 0.0946 0.17 Q . . . .

9.23 0.0963 0.17 Q . . . .

9.35 0.0980 0.17 Q . . . .

9.47 0.0998 0.17 Q . . . .

9.60 0.1015 0.18 Q . . . .

9.72 0.1033 0.18 Q . . . .

9.84 0.1052 0.18 Q . . . .

9.96 0.1070 0.18 Q . . . .

10.09 0.1089 0.18 Q . . . .

10.21 0.1108 0.19 Q . . . .

10.33 0.1127 0.19 Q . . . .

10.46 0.1146 0.19 Q . . . .

10.58 0.1166 0.19 Q . . . .

10.70 0.1186 0.20 Q . . . .

10.83 0.1206 0.20 Q . . . .

10.95 0.1227 0.20 Q . . . .

11.07 0.1248 0.21 Q . . . .

11.20 0.1269 0.21 Q . . . .

11.32 0.1290 0.21 Q . . . .

11.44 0.1312 0.22 Q . . . .

11.57 0.1335 0.22 Q . . . .

11.69 0.1357 0.22 Q . . . .

11.81 0.1380 0.23 Q . . . .

11.94 0.1404 0.23 Q . . . .

12.06 0.1428 0.24 Q . . . .

12.18 0.1455 0.29 .Q . . . .

12.30 0.1485 0.30 .Q . . . .

12.43 0.1515 0.30 .Q . . . .

12.55 0.1546 0.31 .Q . . . .

Item: 11
1415

12.67 0.1578 0.32 .Q . . . .

12.80 0.1611 0.32 .Q . . . .

12.92 0.1644 0.33 .Q . . . .

13.04 0.1677 0.33 .Q . . . .

13.17 0.1712 0.34 .Q . . . .

13.29 0.1747 0.35 .Q . . . .

13.41 0.1783 0.36 .Q . . . .

13.54 0.1821 0.37 .Q . . . .

13.66 0.1859 0.38 .Q . . . .

13.78 0.1898 0.39 .Q . . . .

13.91 0.1938 0.40 .Q . . . .

14.03 0.1980 0.41 .Q . . . .

14.15 0.2023 0.45 .Q . . . .

14.28 0.2069 0.46 .Q . . . .

14.40 0.2117 0.48 .Q . . . .

14.52 0.2167 0.49 .Q . . . .

14.65 0.2218 0.52 . Q . . . .

14.77 0.2272 0.54 . Q . . . .

14.89 0.2329 0.58 . Q . . . .

15.01 0.2389 0.60 . Q . . . .

15.14 0.2453 0.65 . Q . . . .

15.26 0.2521 0.68 . Q . . . .

15.38 0.2594 0.75 . Q . . . .

15.51 0.2668 0.71 . Q . . . .

15.63 0.2747 0.85 . Q . . . .

15.75 0.2839 0.96 . Q . . . .

15.88 0.2959 1.39 . Q . . . .

16.00 0.3126 1.90 . Q . . . .

16.12 0.3512 5.68 . . . Q . .

16.25 0.3859 1.14 . Q . . . .

16.37 0.3956 0.77 . Q . . . .

16.49 0.4032 0.72 . Q . . . .

16.62 0.4101 0.62 . Q . . . .

16.74 0.4161 0.56 . Q . . . .

16.86 0.4215 0.51 . Q . . . .

16.99 0.4265 0.47 .Q . . . .

17.11 0.4310 0.43 .Q . . . .

17.23 0.4352 0.40 .Q . . . .

17.35 0.4391 0.37 .Q . . . .

17.48 0.4428 0.36 .Q . . . .

17.60 0.4464 0.34 .Q . . . .

17.72 0.4497 0.32 .Q . . . .

17.85 0.4530 0.31 .Q . . . .

17.97 0.4561 0.30 .Q . . . .

18.09 0.4590 0.28 .Q . . . .

18.22 0.4616 0.23 Q . . . .

18.34 0.4639 0.22 Q . . . .

18.46 0.4661 0.21 Q . . . .

18.59 0.4683 0.21 Q . . . .

18.71 0.4704 0.20 Q . . . .

Item: 11
1416

18.83 0.4724 0.20 Q . . . .

18.96 0.4744 0.19 Q . . . .

19.08 0.4763 0.19 Q . . . .

19.20 0.4782 0.18 Q . . . .

19.33 0.4800 0.18 Q . . . .

19.45 0.4818 0.17 Q . . . .

19.57 0.4835 0.17 Q . . . .

19.69 0.4852 0.17 Q . . . .

19.82 0.4869 0.16 Q . . . .

19.94 0.4885 0.16 Q . . . .

20.06 0.4901 0.16 Q . . . .

20.19 0.4917 0.15 Q . . . .

20.31 0.4932 0.15 Q . . . .

20.43 0.4947 0.15 Q . . . .

20.56 0.4962 0.14 Q . . . .

20.68 0.4977 0.14 Q . . . .

20.80 0.4991 0.14 Q . . . .

20.93 0.5005 0.14 Q . . . .

21.05 0.5019 0.14 Q . . . .

21.17 0.5033 0.13 Q . . . .

21.30 0.5046 0.13 Q . . . .

21.42 0.5059 0.13 Q . . . .

21.54 0.5072 0.13 Q . . . .

21.67 0.5085 0.13 Q . . . .

21.79 0.5098 0.12 Q . . . .

21.91 0.5110 0.12 Q . . . .

22.04 0.5123 0.12 Q . . . .

22.16 0.5135 0.12 Q . . . .

22.28 0.5147 0.12 Q . . . .

22.40 0.5159 0.12 Q . . . .

22.53 0.5171 0.11 Q . . . .

22.65 0.5182 0.11 Q . . . .

22.77 0.5194 0.11 Q . . . .

22.90 0.5205 0.11 Q . . . .

23.02 0.5216 0.11 Q . . . .

23.14 0.5228 0.11 Q . . . .

23.27 0.5239 0.11 Q . . . .

23.39 0.5249 0.11 Q . . . .

23.51 0.5260 0.11 Q . . . .

23.64 0.5271 0.10 Q . . . .

23.76 0.5281 0.10 Q . . . .

23.88 0.5292 0.10 Q . . . .

24.01 0.5302 0.10 Q . . . .

24.13 0.5307 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Item: 11
1417
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1441.0
10% 110.8
20% 29.6
30% 14.8
40% 7.4
50% 7.4
60% 7.4
70% 7.4
80% 7.4
90% 7.4
Item: 11
1418
____________________________________________________________________________ ****************************************************************************

SMALL AREA UNIT HYDROGRAPH MODEL
============================================================================ (C) Copyright 1989-2016 Advanced Engineering Software (aes) Ver. 23.0 Release Date: 07/01/2016 License ID 1499
Analysis prepared by:

**************************************************************************** ---------------------------------------------------------------------------- Problem Descriptions:

COSTCO FOOTHILL RANCH
EXISTING DA D 2 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 4.02
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.131
TIME OF CONCENTRATION(MIN.) = 18.01

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 2
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.19
30-MINUTE POINT RAINFALL VALUE(INCHES) = 0.40
1-HOUR POINT RAINFALL VALUE(INCHES) = 0.53
3-HOUR POINT RAINFALL VALUE(INCHES) = 0.89
6-HOUR POINT RAINFALL VALUE(INCHES) = 1.22
24-HOUR POINT RAINFALL VALUE(INCHES) = 2.05
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 0.61
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.07
**************************************************************************** TIME VOLUME Q 0. 2.5 5.0 7.5 10.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.09 0.0000 0.00 Q . . . .

0.39 0.0014 0.12 Q . . . .

Item: 11
1419

0.69 0.0043 0.12 Q . . . .

0.99 0.0073 0.12 Q . . . .

1.29 0.0103 0.12 Q . . . .

1.59 0.0133 0.12 Q . . . .

1.89 0.0163 0.12 Q . . . .

2.19 0.0194 0.13 Q . . . .

2.49 0.0225 0.13 Q . . . .

2.79 0.0257 0.13 Q . . . .

3.09 0.0289 0.13 Q . . . .

3.39 0.0322 0.13 Q . . . .

3.69 0.0355 0.13 Q . . . .

3.99 0.0389 0.14 Q . . . .

4.29 0.0423 0.14 Q . . . .

4.59 0.0458 0.14 Q . . . .

4.89 0.0493 0.14 Q . . . .

5.19 0.0529 0.15 Q . . . .

5.49 0.0565 0.15 Q . . . .

5.79 0.0603 0.15 Q . . . .

6.09 0.0640 0.15 Q . . . .

6.39 0.0679 0.16 Q . . . .

6.69 0.0718 0.16 Q . . . .

6.99 0.0758 0.16 Q . . . .

7.30 0.0799 0.17 Q . . . .

7.60 0.0841 0.17 Q . . . .

7.90 0.0883 0.17 Q . . . .

8.20 0.0927 0.18 Q . . . .

8.50 0.0972 0.18 Q . . . .

8.80 0.1017 0.19 Q . . . .

9.10 0.1064 0.19 Q . . . .

9.40 0.1112 0.20 Q . . . .

9.70 0.1162 0.20 Q . . . .

10.00 0.1213 0.21 Q . . . .

10.30 0.1265 0.22 Q . . . .

10.60 0.1319 0.22 Q . . . .

10.90 0.1375 0.23 Q . . . .

11.20 0.1433 0.24 Q . . . .

11.50 0.1493 0.25 Q . . . .

11.80 0.1556 0.26 .Q . . . .

12.10 0.1621 0.27 .Q . . . .

12.40 0.1697 0.34 .Q . . . .

12.70 0.1784 0.36 .Q . . . .

13.00 0.1874 0.37 .Q . . . .

13.30 0.1970 0.40 .Q . . . .

13.60 0.2071 0.41 .Q . . . .

13.90 0.2178 0.45 .Q . . . .

14.20 0.2294 0.48 .Q . . . .

14.50 0.2421 0.55 . Q . . . .

14.80 0.2563 0.59 . Q . . . .

15.10 0.2722 0.70 . Q . . . .

15.40 0.2904 0.77 . Q . . . .

Item: 11
1420

15.70 0.3115 0.93 . Q . . . .

16.00 0.3391 1.29 . Q . . . .

16.30 0.4035 3.90 . . Q . . .

16.60 0.4623 0.84 . Q . . . .

16.90 0.4806 0.64 . Q . . . .

17.20 0.4950 0.52 . Q . . . .

17.50 0.5068 0.43 .Q . . . .

17.80 0.5169 0.38 .Q . . . .

18.10 0.5260 0.35 .Q . . . .

18.40 0.5336 0.26 .Q . . . .

18.70 0.5399 0.24 Q . . . .

19.00 0.5457 0.23 Q . . . .

19.30 0.5511 0.21 Q . . . .

19.60 0.5562 0.20 Q . . . .

19.90 0.5610 0.19 Q . . . .

20.20 0.5656 0.18 Q . . . .

20.50 0.5700 0.17 Q . . . .

20.80 0.5742 0.16 Q . . . .

21.10 0.5782 0.16 Q . . . .

21.40 0.5820 0.15 Q . . . .

21.70 0.5857 0.15 Q . . . .

22.00 0.5893 0.14 Q . . . .

22.30 0.5928 0.14 Q . . . .

22.60 0.5962 0.13 Q . . . .

22.90 0.5994 0.13 Q . . . .

23.20 0.6026 0.13 Q . . . .

23.50 0.6057 0.12 Q . . . .

23.80 0.6087 0.12 Q . . . .

24.10 0.6116 0.12 Q . . . .

24.40 0.6131 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1440.8
10% 270.1
20% 72.0
30% 36.0
40% 18.0
50% 18.0
60% 18.0
70% 18.0
80% 18.0
90% 18.0
Item: 11
1421
____________________________________________________________________________ ****************************************************************************

SMALL AREA UNIT HYDROGRAPH MODEL
============================================================================ (C) Copyright 1989-2016 Advanced Engineering Software (aes) Ver. 23.0 Release Date: 07/01/2016 License ID 1499
Analysis prepared by:

**************************************************************************** ---------------------------------------------------------------------------- Problem Descriptions:

COSTCO FOOTHILL RANCH
EXISTING DA A 100 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 1.45
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.131
TIME OF CONCENTRATION(MIN.) = 6.40

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 100
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.52
30-MINUTE POINT RAINFALL VALUE(INCHES) = 1.09
1-HOUR POINT RAINFALL VALUE(INCHES) = 1.45
3-HOUR POINT RAINFALL VALUE(INCHES) = 2.43
6-HOUR POINT RAINFALL VALUE(INCHES) = 3.36
24-HOUR POINT RAINFALL VALUE(INCHES) = 5.63
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 0.61
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.07
**************************************************************************** TIME VOLUME Q 0. 2.5 5.0 7.5 10.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.11 0.0005 0.11 Q . . . .

0.21 0.0015 0.11 Q . . . .

Item: 11
1422

0.32 0.0025 0.12 Q . . . .

0.43 0.0035 0.12 Q . . . .

0.53 0.0046 0.12 Q . . . .

0.64 0.0056 0.12 Q . . . .

0.75 0.0066 0.12 Q . . . .

0.85 0.0076 0.12 Q . . . .

0.96 0.0087 0.12 Q . . . .

1.07 0.0097 0.12 Q . . . .

1.17 0.0108 0.12 Q . . . .

1.28 0.0118 0.12 Q . . . .

1.39 0.0129 0.12 Q . . . .

1.49 0.0139 0.12 Q . . . .

1.60 0.0150 0.12 Q . . . .

1.71 0.0161 0.12 Q . . . .

1.81 0.0172 0.12 Q . . . .

1.92 0.0182 0.12 Q . . . .

2.03 0.0193 0.12 Q . . . .

2.13 0.0204 0.12 Q . . . .

2.24 0.0215 0.12 Q . . . .

2.35 0.0226 0.13 Q . . . .

2.45 0.0237 0.13 Q . . . .

2.56 0.0248 0.13 Q . . . .

2.67 0.0260 0.13 Q . . . .

2.77 0.0271 0.13 Q . . . .

2.88 0.0282 0.13 Q . . . .

2.99 0.0294 0.13 Q . . . .

3.09 0.0305 0.13 Q . . . .

3.20 0.0316 0.13 Q . . . .

3.31 0.0328 0.13 Q . . . .

3.41 0.0340 0.13 Q . . . .

3.52 0.0351 0.13 Q . . . .

3.63 0.0363 0.13 Q . . . .

3.73 0.0375 0.13 Q . . . .

3.84 0.0387 0.13 Q . . . .

3.95 0.0399 0.14 Q . . . .

4.05 0.0411 0.14 Q . . . .

4.16 0.0423 0.14 Q . . . .

4.27 0.0435 0.14 Q . . . .

4.37 0.0447 0.14 Q . . . .

4.48 0.0459 0.14 Q . . . .

4.59 0.0471 0.14 Q . . . .

4.69 0.0484 0.14 Q . . . .

4.80 0.0496 0.14 Q . . . .

4.91 0.0509 0.14 Q . . . .

5.01 0.0522 0.14 Q . . . .

5.12 0.0534 0.14 Q . . . .

5.23 0.0547 0.15 Q . . . .

5.33 0.0560 0.15 Q . . . .

5.44 0.0573 0.15 Q . . . .

5.55 0.0586 0.15 Q . . . .

Item: 11
1423

5.65 0.0599 0.15 Q . . . .

5.76 0.0612 0.15 Q . . . .

5.87 0.0625 0.15 Q . . . .

5.97 0.0639 0.15 Q . . . .

6.08 0.0652 0.15 Q . . . .

6.19 0.0666 0.15 Q . . . .

6.29 0.0679 0.16 Q . . . .

6.40 0.0693 0.16 Q . . . .

6.51 0.0707 0.16 Q . . . .

6.61 0.0721 0.16 Q . . . .

6.72 0.0735 0.16 Q . . . .

6.83 0.0749 0.16 Q . . . .

6.93 0.0763 0.16 Q . . . .

7.04 0.0777 0.16 Q . . . .

7.15 0.0792 0.16 Q . . . .

7.25 0.0806 0.17 Q . . . .

7.36 0.0821 0.17 Q . . . .

7.47 0.0836 0.17 Q . . . .

7.57 0.0851 0.17 Q . . . .

7.68 0.0866 0.17 Q . . . .

7.79 0.0881 0.17 Q . . . .

7.89 0.0896 0.17 Q . . . .

8.00 0.0911 0.18 Q . . . .

8.11 0.0927 0.18 Q . . . .

8.21 0.0942 0.18 Q . . . .

8.32 0.0958 0.18 Q . . . .

8.43 0.0974 0.18 Q . . . .

8.53 0.0990 0.18 Q . . . .

8.64 0.1006 0.18 Q . . . .

8.75 0.1023 0.19 Q . . . .

8.85 0.1039 0.19 Q . . . .

8.96 0.1056 0.19 Q . . . .

9.07 0.1072 0.19 Q . . . .

9.17 0.1089 0.19 Q . . . .

9.28 0.1106 0.20 Q . . . .

9.39 0.1124 0.20 Q . . . .

9.49 0.1141 0.20 Q . . . .

9.60 0.1159 0.20 Q . . . .

9.71 0.1176 0.20 Q . . . .

9.81 0.1194 0.20 Q . . . .

9.92 0.1213 0.21 Q . . . .

10.03 0.1231 0.21 Q . . . .

10.13 0.1250 0.21 Q . . . .

10.24 0.1268 0.21 Q . . . .

10.35 0.1287 0.22 Q . . . .

10.45 0.1307 0.22 Q . . . .

10.56 0.1326 0.22 Q . . . .

10.67 0.1346 0.22 Q . . . .

10.77 0.1366 0.23 Q . . . .

10.88 0.1386 0.23 Q . . . .

Item: 11
1424

10.99 0.1406 0.23 Q . . . .

11.09 0.1427 0.24 Q . . . .

11.20 0.1448 0.24 Q . . . .

11.31 0.1469 0.24 Q . . . .

11.41 0.1491 0.25 Q . . . .

11.52 0.1513 0.25 Q . . . .

11.63 0.1535 0.25 .Q . . . .

11.73 0.1558 0.26 .Q . . . .

11.84 0.1581 0.26 .Q . . . .

11.95 0.1604 0.27 .Q . . . .

12.05 0.1628 0.29 .Q . . . .

12.16 0.1656 0.34 .Q . . . .

12.27 0.1687 0.35 .Q . . . .

12.37 0.1718 0.35 .Q . . . .

12.48 0.1750 0.36 .Q . . . .

12.59 0.1782 0.37 .Q . . . .

12.69 0.1814 0.37 .Q . . . .

12.80 0.1847 0.38 .Q . . . .

12.91 0.1881 0.39 .Q . . . .

13.01 0.1915 0.39 .Q . . . .

13.12 0.1950 0.40 .Q . . . .

13.23 0.1986 0.41 .Q . . . .

13.33 0.2022 0.42 .Q . . . .

13.44 0.2060 0.42 .Q . . . .

13.55 0.2097 0.44 .Q . . . .

13.65 0.2136 0.44 .Q . . . .

13.76 0.2176 0.46 .Q . . . .

13.87 0.2217 0.47 .Q . . . .

13.97 0.2258 0.48 .Q . . . .

14.08 0.2301 0.49 .Q . . . .

14.19 0.2345 0.51 . Q . . . .

14.29 0.2391 0.52 . Q . . . .

14.40 0.2438 0.55 . Q . . . .

14.51 0.2487 0.56 . Q . . . .

14.61 0.2538 0.59 . Q . . . .

14.72 0.2590 0.60 . Q . . . .

14.83 0.2645 0.64 . Q . . . .

14.93 0.2702 0.66 . Q . . . .

15.04 0.2762 0.71 . Q . . . .

15.15 0.2826 0.73 . Q . . . .

15.25 0.2893 0.80 . Q . . . .

15.36 0.2965 0.84 . Q . . . .

15.47 0.3039 0.83 . Q . . . .

15.57 0.3114 0.89 . Q . . . .

15.68 0.3200 1.07 . Q . . . .

15.79 0.3301 1.20 . Q . . . .

15.89 0.3429 1.71 . Q . . . .

16.00 0.3607 2.34 . Q. . . .

16.11 0.4021 7.04 . . . Q . .

16.21 0.4393 1.40 . Q . . . .

Item: 11
1425

16.32 0.4497 0.97 . Q . . . .

16.43 0.4577 0.84 . Q . . . .

16.53 0.4648 0.76 . Q . . . .

16.64 0.4712 0.68 . Q . . . .

16.75 0.4769 0.62 . Q . . . .

16.85 0.4821 0.57 . Q . . . .

16.96 0.4870 0.53 . Q . . . .

17.07 0.4916 0.50 . Q . . . .

17.17 0.4959 0.47 .Q . . . .

17.28 0.5000 0.45 .Q . . . .

17.39 0.5039 0.43 .Q . . . .

17.49 0.5076 0.41 .Q . . . .

17.60 0.5111 0.40 .Q . . . .

17.71 0.5146 0.38 .Q . . . .

17.81 0.5179 0.37 .Q . . . .

17.92 0.5211 0.36 .Q . . . .

18.03 0.5242 0.35 .Q . . . .

18.13 0.5269 0.27 .Q . . . .

18.24 0.5292 0.26 .Q . . . .

18.35 0.5315 0.25 .Q . . . .

18.45 0.5337 0.24 Q . . . .

18.56 0.5358 0.24 Q . . . .

18.67 0.5379 0.23 Q . . . .

18.77 0.5399 0.23 Q . . . .

18.88 0.5419 0.22 Q . . . .

18.99 0.5438 0.22 Q . . . .

19.09 0.5457 0.21 Q . . . .

19.20 0.5475 0.21 Q . . . .

19.31 0.5493 0.20 Q . . . .

19.41 0.5511 0.20 Q . . . .

19.52 0.5528 0.19 Q . . . .

19.63 0.5545 0.19 Q . . . .

19.73 0.5562 0.19 Q . . . .

19.84 0.5578 0.18 Q . . . .

19.95 0.5594 0.18 Q . . . .

20.05 0.5610 0.18 Q . . . .

20.16 0.5625 0.17 Q . . . .

20.27 0.5640 0.17 Q . . . .

20.37 0.5655 0.17 Q . . . .

20.48 0.5670 0.17 Q . . . .

20.59 0.5685 0.16 Q . . . .

20.69 0.5699 0.16 Q . . . .

20.80 0.5713 0.16 Q . . . .

20.91 0.5727 0.16 Q . . . .

21.01 0.5741 0.15 Q . . . .

21.12 0.5754 0.15 Q . . . .

21.23 0.5768 0.15 Q . . . .

21.33 0.5781 0.15 Q . . . .

21.44 0.5794 0.15 Q . . . .

21.55 0.5807 0.14 Q . . . .

Item: 11
1426

21.65 0.5819 0.14 Q . . . .

21.76 0.5832 0.14 Q . . . .

21.87 0.5844 0.14 Q . . . .

21.97 0.5857 0.14 Q . . . .

22.08 0.5869 0.14 Q . . . .

22.19 0.5881 0.14 Q . . . .

22.29 0.5893 0.13 Q . . . .

22.40 0.5904 0.13 Q . . . .

22.51 0.5916 0.13 Q . . . .

22.61 0.5927 0.13 Q . . . .

22.72 0.5939 0.13 Q . . . .

22.83 0.5950 0.13 Q . . . .

22.93 0.5961 0.13 Q . . . .

23.04 0.5972 0.12 Q . . . .

23.15 0.5983 0.12 Q . . . .

23.25 0.5994 0.12 Q . . . .

23.36 0.6005 0.12 Q . . . .

23.47 0.6015 0.12 Q . . . .

23.57 0.6026 0.12 Q . . . .

23.68 0.6036 0.12 Q . . . .

23.79 0.6047 0.12 Q . . . .

23.89 0.6057 0.12 Q . . . .

24.00 0.6067 0.11 Q . . . .

24.11 0.6072 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1440.0
10% 96.0
20% 19.2
30% 12.8
40% 6.4
50% 6.4
60% 6.4
70% 6.4
80% 6.4
90% 6.4
Item: 11
1427
____________________________________________________________________________ ****************************************************************************

SMALL AREA UNIT HYDROGRAPH MODEL
============================================================================ (C) Copyright 1989-2016 Advanced Engineering Software (aes) Ver. 23.0 Release Date: 07/01/2016 License ID 1499
Analysis prepared by:

**************************************************************************** ---------------------------------------------------------------------------- Problem Descriptions:

COSTCO FOOTHILL RANCH
EXISTING DA B 100 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 6.28
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.131
TIME OF CONCENTRATION(MIN.) = 8.82

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 100
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.52
30-MINUTE POINT RAINFALL VALUE(INCHES) = 1.09
1-HOUR POINT RAINFALL VALUE(INCHES) = 1.45
3-HOUR POINT RAINFALL VALUE(INCHES) = 2.43
6-HOUR POINT RAINFALL VALUE(INCHES) = 3.36
24-HOUR POINT RAINFALL VALUE(INCHES) = 5.63
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 2.63
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.31
**************************************************************************** TIME VOLUME Q 0. 7.5 15.0 22.5 30.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.12 0.0030 0.49 Q . . . .

0.27 0.0090 0.50 Q . . . .

Item: 11
1428

0.42 0.0151 0.50 Q . . . .

0.57 0.0212 0.50 Q . . . .

0.71 0.0273 0.50 Q . . . .

0.86 0.0334 0.51 Q . . . .

1.01 0.0396 0.51 Q . . . .

1.15 0.0459 0.52 Q . . . .

1.30 0.0521 0.52 Q . . . .

1.45 0.0585 0.52 Q . . . .

1.59 0.0648 0.52 Q . . . .

1.74 0.0712 0.53 Q . . . .

1.89 0.0776 0.53 Q . . . .

2.04 0.0841 0.54 Q . . . .

2.18 0.0906 0.54 Q . . . .

2.33 0.0972 0.54 Q . . . .

2.48 0.1038 0.54 Q . . . .

2.62 0.1104 0.55 Q . . . .

2.77 0.1171 0.55 Q . . . .

2.92 0.1239 0.56 Q . . . .

3.06 0.1307 0.56 Q . . . .

3.21 0.1375 0.57 Q . . . .

3.36 0.1444 0.57 Q . . . .

3.51 0.1513 0.57 Q . . . .

3.65 0.1583 0.58 Q . . . .

3.80 0.1654 0.58 Q . . . .

3.95 0.1724 0.59 Q . . . .

4.09 0.1796 0.59 Q . . . .

4.24 0.1868 0.59 Q . . . .

4.39 0.1940 0.60 Q . . . .

4.53 0.2014 0.60 Q . . . .

4.68 0.2087 0.61 Q . . . .

4.83 0.2162 0.61 Q . . . .

4.98 0.2237 0.62 Q . . . .

5.12 0.2312 0.62 Q . . . .

5.27 0.2388 0.63 Q . . . .

5.42 0.2465 0.63 Q . . . .

5.56 0.2543 0.64 Q . . . .

5.71 0.2621 0.65 Q . . . .

5.86 0.2700 0.65 Q . . . .

6.00 0.2779 0.66 Q . . . .

6.15 0.2860 0.67 Q . . . .

6.30 0.2941 0.67 Q . . . .

6.45 0.3023 0.68 Q . . . .

6.59 0.3105 0.68 Q . . . .

6.74 0.3189 0.69 Q . . . .

6.89 0.3273 0.70 Q . . . .

7.03 0.3358 0.71 Q . . . .

7.18 0.3444 0.71 Q . . . .

7.33 0.3531 0.72 Q . . . .

7.47 0.3619 0.73 Q . . . .

7.62 0.3707 0.74 Q . . . .

Item: 11
1429

7.77 0.3797 0.74 Q . . . .

7.92 0.3888 0.75 .Q . . . .

8.06 0.3979 0.76 .Q . . . .

8.21 0.4072 0.77 .Q . . . .

8.36 0.4166 0.78 .Q . . . .

8.50 0.4261 0.79 .Q . . . .

8.65 0.4357 0.79 .Q . . . .

8.80 0.4455 0.81 .Q . . . .

8.94 0.4553 0.81 .Q . . . .

9.09 0.4653 0.83 .Q . . . .

9.24 0.4754 0.84 .Q . . . .

9.39 0.4857 0.85 .Q . . . .

9.53 0.4961 0.86 .Q . . . .

9.68 0.5066 0.88 .Q . . . .

9.83 0.5173 0.88 .Q . . . .

9.97 0.5281 0.90 .Q . . . .

10.12 0.5391 0.91 .Q . . . .

10.27 0.5503 0.93 .Q . . . .

10.41 0.5617 0.94 .Q . . . .

10.56 0.5732 0.96 .Q . . . .

10.71 0.5850 0.97 .Q . . . .

10.85 0.5969 0.99 .Q . . . .

11.00 0.6091 1.01 .Q . . . .

11.15 0.6215 1.03 .Q . . . .

11.30 0.6341 1.04 .Q . . . .

11.44 0.6469 1.07 .Q . . . .

11.59 0.6600 1.09 .Q . . . .

11.74 0.6734 1.12 .Q . . . .

11.88 0.6871 1.13 .Q . . . .

12.03 0.7010 1.17 .Q . . . .

12.18 0.7168 1.43 .Q . . . .

12.32 0.7348 1.53 . Q . . . .

12.47 0.7534 1.55 . Q . . . .

12.62 0.7725 1.59 . Q . . . .

12.77 0.7920 1.62 . Q . . . .

12.91 0.8120 1.67 . Q . . . .

13.06 0.8325 1.70 . Q . . . .

13.21 0.8535 1.76 . Q . . . .

13.35 0.8750 1.79 . Q . . . .

13.50 0.8972 1.86 . Q . . . .

13.65 0.9201 1.90 . Q . . . .

13.80 0.9437 1.99 . Q . . . .

13.94 0.9681 2.03 . Q . . . .

14.09 0.9935 2.14 . Q . . . .

14.24 1.0198 2.20 . Q . . . .

14.38 1.0474 2.33 . Q . . . .

14.53 1.0762 2.41 . Q . . . .

14.68 1.1065 2.58 . Q . . . .

14.82 1.1385 2.68 . Q . . . .

14.97 1.1725 2.92 . Q . . . .

Item: 11
1430

15.12 1.2088 3.06 . Q . . . .

15.27 1.2482 3.42 . Q . . . .

15.41 1.2912 3.66 . Q . . . .

15.56 1.3367 3.83 . Q . . . .

15.71 1.3861 4.31 . Q . . . .

15.85 1.4496 6.14 . Q . . . .

16.00 1.5378 8.38 . .Q . . .

16.15 1.7422 25.28 . . . . Q .

16.29 1.9262 5.01 . Q . . . .

16.44 1.9783 3.56 . Q . . . .

16.59 2.0195 3.23 . Q . . . .

16.73 2.0561 2.79 . Q . . . .

16.88 2.0881 2.49 . Q . . . .

17.03 2.1170 2.27 . Q . . . .

17.18 2.1434 2.08 . Q . . . .

17.32 2.1679 1.94 . Q . . . .

17.47 2.1908 1.83 . Q . . . .

17.62 2.2124 1.73 . Q . . . .

17.76 2.2328 1.64 . Q . . . .

17.91 2.2524 1.57 . Q . . . .

18.06 2.2711 1.51 . Q . . . .

18.20 2.2872 1.15 .Q . . . .

18.35 2.3009 1.10 .Q . . . .

18.50 2.3140 1.06 .Q . . . .

18.65 2.3266 1.02 .Q . . . .

18.79 2.3387 0.98 .Q . . . .

18.94 2.3505 0.95 .Q . . . .

19.09 2.3618 0.92 .Q . . . .

19.23 2.3729 0.89 .Q . . . .

19.38 2.3836 0.87 .Q . . . .

19.53 2.3939 0.84 .Q . . . .

19.67 2.4041 0.82 .Q . . . .

19.82 2.4139 0.80 .Q . . . .

19.97 2.4235 0.78 .Q . . . .

20.12 2.4329 0.76 .Q . . . .

20.26 2.4421 0.75 Q . . . .

20.41 2.4511 0.73 Q . . . .

20.56 2.4598 0.71 Q . . . .

20.70 2.4684 0.70 Q . . . .

20.85 2.4769 0.69 Q . . . .

21.00 2.4851 0.67 Q . . . .

21.14 2.4932 0.66 Q . . . .

21.29 2.5012 0.65 Q . . . .

21.44 2.5090 0.64 Q . . . .

21.59 2.5167 0.63 Q . . . .

21.73 2.5243 0.62 Q . . . .

21.88 2.5317 0.61 Q . . . .

22.03 2.5390 0.60 Q . . . .

22.17 2.5462 0.59 Q . . . .

22.32 2.5533 0.58 Q . . . .

Item: 11
1431

22.47 2.5603 0.57 Q . . . .

22.61 2.5672 0.56 Q . . . .

22.76 2.5740 0.55 Q . . . .

22.91 2.5807 0.55 Q . . . .

23.06 2.5873 0.54 Q . . . .

23.20 2.5938 0.53 Q . . . .

23.35 2.6002 0.53 Q . . . .

23.50 2.6066 0.52 Q . . . .

23.64 2.6128 0.51 Q . . . .

23.79 2.6190 0.51 Q . . . .

23.94 2.6252 0.50 Q . . . .

24.08 2.6312 0.50 Q . . . .

24.23 2.6342 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1446.5
10% 132.3
20% 26.5
30% 17.6
40% 8.8
50% 8.8
60% 8.8
70% 8.8
80% 8.8
90% 8.8
Item: 11
1432
____________________________________________________________________________ ****************************************************************************

SMALL AREA UNIT HYDROGRAPH MODEL
============================================================================ (C) Copyright 1989-2016 Advanced Engineering Software (aes) Ver. 23.0 Release Date: 07/01/2016 License ID 1499
Analysis prepared by:

**************************************************************************** ---------------------------------------------------------------------------- Problem Descriptions:

COSTCO FOOTHILL RANCH
EXISTING DA C 100 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 3.48
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.131
TIME OF CONCENTRATION(MIN.) = 7.39

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 100
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.52
30-MINUTE POINT RAINFALL VALUE(INCHES) = 1.09
1-HOUR POINT RAINFALL VALUE(INCHES) = 1.45
3-HOUR POINT RAINFALL VALUE(INCHES) = 2.43
6-HOUR POINT RAINFALL VALUE(INCHES) = 3.36
24-HOUR POINT RAINFALL VALUE(INCHES) = 5.63
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 1.46
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.18
**************************************************************************** TIME VOLUME Q 0. 5.0 10.0 15.0 20.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.11 0.0013 0.27 Q . . . .

0.23 0.0041 0.27 Q . . . .

Item: 11
1433

0.36 0.0069 0.28 Q . . . .

0.48 0.0097 0.28 Q . . . .

0.60 0.0125 0.28 Q . . . .

0.73 0.0154 0.28 Q . . . .

0.85 0.0182 0.28 Q . . . .

0.97 0.0211 0.28 Q . . . .

1.10 0.0240 0.29 Q . . . .

1.22 0.0269 0.29 Q . . . .

1.34 0.0298 0.29 Q . . . .

1.47 0.0328 0.29 Q . . . .

1.59 0.0357 0.29 Q . . . .

1.71 0.0387 0.29 Q . . . .

1.84 0.0417 0.29 Q . . . .

1.96 0.0447 0.30 Q . . . .

2.08 0.0477 0.30 Q . . . .

2.21 0.0507 0.30 Q . . . .

2.33 0.0538 0.30 Q . . . .

2.45 0.0568 0.30 Q . . . .

2.57 0.0599 0.30 Q . . . .

2.70 0.0630 0.31 Q . . . .

2.82 0.0661 0.31 Q . . . .

2.94 0.0693 0.31 Q . . . .

3.07 0.0724 0.31 Q . . . .

3.19 0.0756 0.31 Q . . . .

3.31 0.0788 0.32 Q . . . .

3.44 0.0820 0.32 Q . . . .

3.56 0.0853 0.32 Q . . . .

3.68 0.0885 0.32 Q . . . .

3.81 0.0918 0.32 Q . . . .

3.93 0.0951 0.32 Q . . . .

4.05 0.0984 0.33 Q . . . .

4.18 0.1017 0.33 Q . . . .

4.30 0.1051 0.33 Q . . . .

4.42 0.1085 0.33 Q . . . .

4.55 0.1119 0.34 Q . . . .

4.67 0.1153 0.34 Q . . . .

4.79 0.1188 0.34 Q . . . .

4.92 0.1222 0.34 Q . . . .

5.04 0.1257 0.35 Q . . . .

5.16 0.1293 0.35 Q . . . .

5.28 0.1328 0.35 Q . . . .

5.41 0.1364 0.35 Q . . . .

5.53 0.1400 0.36 Q . . . .

5.65 0.1436 0.36 Q . . . .

5.78 0.1473 0.36 Q . . . .

5.90 0.1509 0.36 Q . . . .

6.02 0.1546 0.37 Q . . . .

6.15 0.1584 0.37 Q . . . .

6.27 0.1621 0.37 Q . . . .

6.39 0.1659 0.37 Q . . . .

Item: 11
1434

6.52 0.1698 0.38 Q . . . .

6.64 0.1736 0.38 Q . . . .

6.76 0.1775 0.38 Q . . . .

6.89 0.1814 0.39 Q . . . .

7.01 0.1854 0.39 Q . . . .

7.13 0.1894 0.39 Q . . . .

7.26 0.1934 0.40 Q . . . .

7.38 0.1974 0.40 Q . . . .

7.50 0.2015 0.40 Q . . . .

7.62 0.2057 0.41 Q . . . .

7.75 0.2098 0.41 Q . . . .

7.87 0.2140 0.41 Q . . . .

7.99 0.2183 0.42 Q . . . .

8.12 0.2226 0.42 Q . . . .

8.24 0.2269 0.43 Q . . . .

8.36 0.2313 0.43 Q . . . .

8.49 0.2357 0.44 Q . . . .

8.61 0.2401 0.44 Q . . . .

8.73 0.2447 0.45 Q . . . .

8.86 0.2492 0.45 Q . . . .

8.98 0.2538 0.46 Q . . . .

9.10 0.2585 0.46 Q . . . .

9.23 0.2632 0.47 Q . . . .

9.35 0.2679 0.47 Q . . . .

9.47 0.2727 0.48 Q . . . .

9.60 0.2776 0.48 Q . . . .

9.72 0.2825 0.49 Q . . . .

9.84 0.2875 0.49 Q . . . .

9.96 0.2926 0.50 .Q . . . .

10.09 0.2977 0.50 .Q . . . .

10.21 0.3029 0.51 .Q . . . .

10.33 0.3081 0.52 .Q . . . .

10.46 0.3134 0.53 .Q . . . .

10.58 0.3188 0.53 .Q . . . .

10.70 0.3243 0.54 .Q . . . .

10.83 0.3298 0.55 .Q . . . .

10.95 0.3355 0.56 .Q . . . .

11.07 0.3412 0.56 .Q . . . .

11.20 0.3470 0.58 .Q . . . .

11.32 0.3529 0.58 .Q . . . .

11.44 0.3589 0.60 .Q . . . .

11.57 0.3650 0.60 .Q . . . .

11.69 0.3712 0.62 .Q . . . .

11.81 0.3775 0.62 .Q . . . .

11.94 0.3839 0.64 .Q . . . .

12.06 0.3904 0.65 .Q . . . .

12.18 0.3979 0.83 .Q . . . .

12.30 0.4065 0.84 .Q . . . .

12.43 0.4151 0.86 .Q . . . .

12.55 0.4239 0.87 .Q . . . .

Item: 11
1435

12.67 0.4329 0.89 .Q . . . .

12.80 0.4421 0.90 .Q . . . .

12.92 0.4514 0.93 .Q . . . .

13.04 0.4609 0.94 .Q . . . .

13.17 0.4707 0.97 .Q . . . .

13.29 0.4806 0.99 .Q . . . .

13.41 0.4908 1.02 . Q . . . .

13.54 0.5012 1.03 . Q . . . .

13.66 0.5120 1.07 . Q . . . .

13.78 0.5230 1.09 . Q . . . .

13.91 0.5343 1.13 . Q . . . .

14.03 0.5459 1.16 . Q . . . .

14.15 0.5580 1.22 . Q . . . .

14.28 0.5705 1.24 . Q . . . .

14.40 0.5835 1.31 . Q . . . .

14.52 0.5970 1.34 . Q . . . .

14.65 0.6111 1.42 . Q . . . .

14.77 0.6257 1.47 . Q . . . .

14.89 0.6412 1.57 . Q . . . .

15.01 0.6575 1.63 . Q . . . .

15.14 0.6748 1.78 . Q . . . .

15.26 0.6933 1.86 . Q . . . .

15.38 0.7133 2.05 . Q . . . .

15.51 0.7337 1.96 . Q . . . .

15.63 0.7556 2.35 . Q . . . .

15.75 0.7811 2.65 . Q . . . .

15.88 0.8138 3.77 . Q . . . .

16.00 0.8592 5.15 . Q . . .

16.12 0.9645 15.54 . . . .Q .

16.25 1.0593 3.09 . Q . . . .

16.37 1.0859 2.13 . Q . . . .

16.49 1.1068 1.96 . Q . . . .

16.62 1.1254 1.70 . Q . . . .

16.74 1.1417 1.52 . Q . . . .

16.86 1.1565 1.38 . Q . . . .

16.99 1.1700 1.27 . Q . . . .

17.11 1.1825 1.18 . Q . . . .

17.23 1.1942 1.11 . Q . . . .

17.35 1.2052 1.05 . Q . . . .

17.48 1.2157 1.00 . Q . . . .

17.60 1.2256 0.96 .Q . . . .

17.72 1.2351 0.92 .Q . . . .

17.85 1.2443 0.88 .Q . . . .

17.97 1.2531 0.85 .Q . . . .

18.09 1.2614 0.77 .Q . . . .

18.22 1.2685 0.63 .Q . . . .

18.34 1.2748 0.61 .Q . . . .

18.46 1.2809 0.59 .Q . . . .

18.59 1.2868 0.57 .Q . . . .

18.71 1.2925 0.55 .Q . . . .

Item: 11
1436

18.83 1.2981 0.54 .Q . . . .

18.96 1.3035 0.52 .Q . . . .

19.08 1.3087 0.51 .Q . . . .

19.20 1.3139 0.50 Q . . . .

19.33 1.3188 0.48 Q . . . .

19.45 1.3237 0.47 Q . . . .

19.57 1.3285 0.46 Q . . . .

19.69 1.3331 0.45 Q . . . .

19.82 1.3377 0.44 Q . . . .

19.94 1.3421 0.43 Q . . . .

20.06 1.3465 0.43 Q . . . .

20.19 1.3508 0.42 Q . . . .

20.31 1.3550 0.41 Q . . . .

20.43 1.3591 0.40 Q . . . .

20.56 1.3632 0.40 Q . . . .

20.68 1.3672 0.39 Q . . . .

20.80 1.3711 0.38 Q . . . .

20.93 1.3750 0.38 Q . . . .

21.05 1.3788 0.37 Q . . . .

21.17 1.3825 0.36 Q . . . .

21.30 1.3862 0.36 Q . . . .

21.42 1.3898 0.35 Q . . . .

21.54 1.3934 0.35 Q . . . .

21.67 1.3969 0.34 Q . . . .

21.79 1.4004 0.34 Q . . . .

21.91 1.4038 0.33 Q . . . .

22.04 1.4072 0.33 Q . . . .

22.16 1.4105 0.33 Q . . . .

22.28 1.4138 0.32 Q . . . .

22.40 1.4171 0.32 Q . . . .

22.53 1.4203 0.31 Q . . . .

22.65 1.4234 0.31 Q . . . .

22.77 1.4266 0.31 Q . . . .

22.90 1.4297 0.30 Q . . . .

23.02 1.4328 0.30 Q . . . .

23.14 1.4358 0.30 Q . . . .

23.27 1.4388 0.29 Q . . . .

23.39 1.4418 0.29 Q . . . .

23.51 1.4447 0.29 Q . . . .

23.64 1.4476 0.28 Q . . . .

23.76 1.4505 0.28 Q . . . .

23.88 1.4533 0.28 Q . . . .

24.01 1.4561 0.28 Q . . . .

24.13 1.4576 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Item: 11
1437
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1441.0
10% 110.8
20% 22.2
30% 14.8
40% 7.4
50% 7.4
60% 7.4
70% 7.4
80% 7.4
90% 7.4
Item: 11
1438
____________________________________________________________________________ ****************************************************************************

SMALL AREA UNIT HYDROGRAPH MODEL
============================================================================ (C) Copyright 1989-2016 Advanced Engineering Software (aes) Ver. 23.0 Release Date: 07/01/2016 License ID 1499
Analysis prepared by:

**************************************************************************** ---------------------------------------------------------------------------- Problem Descriptions:

COSTCO FOOTHILL RANCH
EXISTING DA D 100 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------------------- RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 4.02
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.131
TIME OF CONCENTRATION(MIN.) = 18.01

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 100
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.52
30-MINUTE POINT RAINFALL VALUE(INCHES) = 1.09
1-HOUR POINT RAINFALL VALUE(INCHES) = 1.45
3-HOUR POINT RAINFALL VALUE(INCHES) = 2.43
6-HOUR POINT RAINFALL VALUE(INCHES) = 3.36
24-HOUR POINT RAINFALL VALUE(INCHES) = 5.63
---------------------------------------------------------------------------- TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 1.68
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.20
**************************************************************************** TIME VOLUME Q 0. 5.0 10.0 15.0 20.0
(HOURS) (AF) (CFS)
----------------------------------------------------------------------------

0.09 0.0000 0.00 Q . . . .

0.39 0.0039 0.32 Q . . . .

Item: 11
1439

0.69 0.0119 0.32 Q . . . .

0.99 0.0199 0.32 Q . . . .

1.29 0.0280 0.33 Q . . . .

1.59 0.0363 0.33 Q . . . .

1.89 0.0446 0.34 Q . . . .

2.19 0.0530 0.34 Q . . . .

2.49 0.0616 0.35 Q . . . .

2.79 0.0703 0.35 Q . . . .

3.09 0.0791 0.36 Q . . . .

3.39 0.0880 0.36 Q . . . .

3.69 0.0971 0.37 Q . . . .

3.99 0.1063 0.37 Q . . . .

4.29 0.1156 0.38 Q . . . .

4.59 0.1251 0.38 Q . . . .

4.89 0.1347 0.39 Q . . . .

5.19 0.1445 0.40 Q . . . .

5.49 0.1545 0.41 Q . . . .

5.79 0.1647 0.41 Q . . . .

6.09 0.1750 0.42 Q . . . .

6.39 0.1855 0.43 Q . . . .

6.69 0.1962 0.44 Q . . . .

6.99 0.2072 0.44 Q . . . .

7.30 0.2184 0.46 Q . . . .

7.60 0.2298 0.46 Q . . . .

7.90 0.2414 0.48 Q . . . .

8.20 0.2533 0.48 Q . . . .

8.50 0.2656 0.50 Q . . . .

8.80 0.2781 0.51 .Q . . . .

9.10 0.2909 0.53 .Q . . . .

9.40 0.3041 0.54 .Q . . . .

9.70 0.3176 0.56 .Q . . . .

10.00 0.3315 0.57 .Q . . . .

10.30 0.3459 0.59 .Q . . . .

10.60 0.3607 0.60 .Q . . . .

10.90 0.3760 0.63 .Q . . . .

11.20 0.3919 0.65 .Q . . . .

11.50 0.4084 0.68 .Q . . . .

11.80 0.4255 0.70 .Q . . . .

12.10 0.4434 0.74 .Q . . . .

12.40 0.4645 0.96 .Q . . . .

12.70 0.4890 1.02 . Q . . . .

13.00 0.5146 1.05 . Q . . . .

13.30 0.5416 1.12 . Q . . . .

13.60 0.5700 1.17 . Q . . . .

13.90 0.6003 1.27 . Q . . . .

14.20 0.6326 1.33 . Q . . . .

14.50 0.6678 1.50 . Q . . . .

14.80 0.7063 1.60 . Q . . . .

15.10 0.7497 1.89 . Q . . . .

15.40 0.7993 2.11 . Q . . . .

Item: 11
1440

15.70 0.8573 2.57 . Q . . . .

16.00 0.9330 3.52 . Q . . . .

16.30 1.1087 10.64 . . .Q . .

16.60 1.2693 2.31 . Q . . . .

16.90 1.3194 1.73 . Q . . . .

17.20 1.3584 1.42 . Q . . . .

17.50 1.3910 1.22 . Q . . . .

17.80 1.4196 1.08 . Q . . . .

18.10 1.4453 0.99 .Q . . . .

18.40 1.4665 0.72 .Q . . . .

18.70 1.4836 0.66 .Q . . . .

19.00 1.4995 0.62 .Q . . . .

19.30 1.5144 0.58 .Q . . . .

19.60 1.5283 0.55 .Q . . . .

19.90 1.5415 0.52 .Q . . . .

20.20 1.5540 0.49 Q . . . .

20.50 1.5659 0.47 Q . . . .

20.80 1.5774 0.45 Q . . . .

21.10 1.5883 0.43 Q . . . .

21.40 1.5988 0.42 Q . . . .

21.70 1.6090 0.40 Q . . . .

22.00 1.6188 0.39 Q . . . .

22.30 1.6283 0.38 Q . . . .

22.60 1.6375 0.37 Q . . . .

22.90 1.6464 0.35 Q . . . .

23.20 1.6551 0.35 Q . . . .

23.50 1.6635 0.34 Q . . . .

23.80 1.6718 0.33 Q . . . .

24.10 1.6798 0.32 Q . . . .

24.40 1.6838 0.00 Q . . . .
---------------------------------------------------------------------------- -------------------------------------------------------------------------------- TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1440.8
10% 288.2
20% 72.0
30% 36.0
40% 18.0
50% 18.0
60% 18.0
70% 18.0
80% 18.0
90% 18.0
Item: 11
1441
_________________________________________________________________ ___________
***************************************************************** ***********

SMALL AREA UNIT HYDROGRAPH MODEL
================================================================= ===========
(C) Copyright 1989-2016 Advanced Engineering Software
(aes)
Ver. 23.0 Release Date: 07/01/2016 License ID
1499
Analysis prepared by:

***************************************************************** ***********
---------------------------------------------------------------- ------------
Problem Descriptions:

COSTCO FOOTHILL RANCH
PROPOSED 2 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------- ------------
RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 15.65
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.157
TIME OF CONCENTRATION(MIN.) = 9.46

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 2
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.19
30-MINUTE POINT RAINFALL VALUE(INCHES) = 0.40
1-HOUR POINT RAINFALL VALUE(INCHES) = 0.53
3-HOUR POINT RAINFALL VALUE(INCHES) = 0.89
6-HOUR POINT RAINFALL VALUE(INCHES) = 1.22
24-HOUR POINT RAINFALL VALUE(INCHES) = 2.05
---------------------------------------------------------------- 1 Item: 11
1442
------------
TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 2.39
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.28
***************************************************************** ***********
TIME VOLUME Q 0. 7.5 15.0 22.5

30.0 (HOURS) (AF) (CFS)
---------------------------------------------------------------- ------------

0.08 0.0014 0.45
Q . . . .

0.23 0.0073 0.45
Q . . . .

0.39 0.0132 0.46
Q . . . .

0.55 0.0191 0.46
Q . . . .

0.71 0.0251 0.46
Q . . . .

0.86 0.0312 0.46
Q . . . .

1.02 0.0372 0.47
Q . . . .

1.18 0.0433 0.47
Q . . . .

1.34 0.0495 0.47
Q . . . .

1.49 0.0557 0.48
Q . . . .

1.65 0.0619 0.48
Q . . . .

1.81 0.0681 0.48
Q . . . .

1.97 0.0745 0.49
Q . . . .

2.13 0.0808 0.49
Q . . . .

2.28 0.0872 0.49
Q . . . .

2.44 0.0937 0.50
Q . . . .

2.60 0.1002 0.50
Q . . . .

2.76 0.1067 0.50
Q . . . .

2.91 0.1133 0.51
Q . . . .

3.07 0.1199 0.51
2 Item: 11
1443
Q . . . .

3.23 0.1266 0.52
Q . . . .

3.39 0.1334 0.52
Q . . . .

3.54 0.1401 0.52
Q . . . .

3.70 0.1470 0.53
Q . . . .

3.86 0.1539 0.53
Q . . . .

4.02 0.1609 0.54
Q . . . .

4.18 0.1679 0.54
Q . . . .

4.33 0.1749 0.54
Q . . . .

4.49 0.1821 0.55
Q . . . .

4.65 0.1893 0.55
Q . . . .

4.81 0.1965 0.56
Q . . . .

4.96 0.2038 0.56
Q . . . .

5.12 0.2112 0.57
Q . . . .

5.28 0.2187 0.57
Q . . . .

5.44 0.2262 0.58
Q . . . .

5.59 0.2338 0.58
Q . . . .

5.75 0.2414 0.59
Q . . . .

5.91 0.2492 0.60
Q . . . .

6.07 0.2570 0.60
Q . . . .

6.22 0.2648 0.61
Q . . . .

6.38 0.2728 0.62
Q . . . .

6.54 0.2808 0.62
Q . . . .

6.70 0.2890 0.63
Q . . . .

6.86 0.2972 0.63
Q . . . .

7.01 0.3055 0.64
Q . . . .

7.17 0.3139 0.65
3 Item: 11
1444
Q . . . .

7.33 0.3224 0.66
Q . . . .

7.49 0.3309 0.66
Q . . . .

7.64 0.3396 0.67
Q . . . .

7.80 0.3484 0.68
Q . . . .

7.96 0.3573 0.69
Q . . . .

8.12 0.3663 0.69
Q . . . .

8.27 0.3754 0.70
Q . . . .

8.43 0.3846 0.71
Q . . . .

8.59 0.3939 0.72
Q . . . .

8.75 0.4034 0.73
Q . . . .

8.90 0.4130 0.74
Q . . . .

9.06 0.4227 0.75
Q . . . .

9.22 0.4325

0.76 .Q . . . .

9.38 0.4425

0.77 .Q . . . .

9.54 0.4527

0.79 .Q . . . .

9.69 0.4630

0.79 .Q . . . .

9.85 0.4734

0.81 .Q . . . .

10.01 0.4840

0.82 .Q . . . .

10.17 0.4948

0.84 .Q . . . .

10.32 0.5058

0.85 .Q . . . .

10.48 0.5170

0.87 .Q . . . .

10.64 0.5283

0.88 .Q . . . .

10.80 0.5399

0.90 .Q . . . .

10.95 0.5517

0.91 .Q . . . .

11.11 0.5637

0.93 .Q . . . .

11.27 0.5759
4 Item: 11
1445

0.95 .Q . . . .

11.43 0.5884

0.97 .Q . . . .

11.59 0.6012

0.99 .Q . . . .

11.74 0.6142

1.02 .Q . . . .

11.90 0.6275

1.03 .Q . . . .

12.06 0.6413

1.08 .Q . . . .

12.22 0.6569

1.31 .Q . . . .

12.37 0.6742

1.35 .Q . . . .

12.53 0.6920

1.37 .Q . . . .

12.69 0.7102

1.42 .Q . . . .

12.85 0.7289

1.44 .Q . . . .

13.00 0.7480

1.50 .Q . . . .

13.16 0.7677 1.53 .

Q . . . .

13.32 0.7880 1.59 .

Q . . . .

13.48 0.8089 1.62 .

Q . . . .

13.63 0.8305 1.69 .

Q . . . .

13.79 0.8529 1.74 .

Q . . . .

13.95 0.8761 1.83 .

Q . . . .

14.11 0.9002 1.88 .

Q . . . .

14.27 0.9259 2.06 .

Q . . . .

14.42 0.9531 2.13 .

Q . . . .

14.58 0.9818 2.28 .

Q . . . .

14.74 1.0120 2.36 .

Q . . . .

14.90 1.0442 2.57 .

Q . . . .

15.05 1.0786 2.70 .

Q . . . .

15.21 1.1158 3.02 .

Q . . . .

15.37 1.1565 3.23 .
5 Item: 11
1446
Q . . . .

15.53 1.1990 3.30 .

Q . . . .

15.68 1.2448 3.72 .

Q . . . .

15.84 1.3043 5.41 .

Q . . . .

16.00 1.3877 7.38 .

Q. . . .

16.16 1.5799 22.12 . . .

Q. .

16.32 1.7524 4.35 .

Q . . . .

16.47 1.8023 3.31 .

Q . . . .

16.63 1.8424 2.85 .

Q . . . .

16.79 1.8770 2.46 .

Q . . . .

16.95 1.9073 2.20 .

Q . . . .

17.10 1.9347 2.00 .

Q . . . .

17.26 1.9593 1.78 .

Q . . . .

17.42 1.9817 1.66 .

Q . . . .

17.58 2.0026 1.56 .

Q . . . .

17.73 2.0223

1.47 .Q . . . .

17.89 2.0410

1.40 .Q . . . .

18.05 2.0588

1.33 .Q . . . .

18.21 2.0743

1.05 .Q . . . .

18.36 2.0877

1.00 .Q . . . .

18.52 2.1004

0.96 .Q . . . .

18.68 2.1127

0.92 .Q . . . .

18.84 2.1245

0.89 .Q . . . .

19.00 2.1358

0.86 .Q . . . .

19.15 2.1468

0.83 .Q . . . .

19.31 2.1574

0.80 .Q . . . .

19.47 2.1677
6 Item: 11
1447

0.78 .Q . . . .

19.63 2.1777

0.76 .Q . . . .

19.78 2.1874 0.74
Q . . . .

19.94 2.1969 0.72
Q . . . .

20.10 2.2061 0.70
Q . . . .

20.26 2.2151 0.68
Q . . . .

20.41 2.2239 0.67
Q . . . .

20.57 2.2325 0.65
Q . . . .

20.73 2.2409 0.64
Q . . . .

20.89 2.2491 0.62
Q . . . .

21.05 2.2571 0.61
Q . . . .

21.20 2.2650 0.60
Q . . . .

21.36 2.2727 0.59
Q . . . .

21.52 2.2803 0.58
Q . . . .

21.68 2.2878 0.57
Q . . . .

21.83 2.2951 0.56
Q . . . .

21.99 2.3023 0.55
Q . . . .

22.15 2.3093 0.54
Q . . . .

22.31 2.3163 0.53
Q . . . .

22.46 2.3231 0.52
Q . . . .

22.62 2.3299 0.51
Q . . . .

22.78 2.3365 0.51
Q . . . .

22.94 2.3431 0.50
Q . . . .

23.09 2.3495 0.49
Q . . . .

23.25 2.3559 0.48
Q . . . .

23.41 2.3621 0.48
Q . . . .

23.57 2.3683 0.47
7 Item: 11
1448
Q . . . .

23.73 2.3744 0.47
Q . . . .

23.88 2.3805 0.46
Q . . . .

24.04 2.3864 0.45
Q . . . .

24.20 2.3894 0.00
Q . . . .
---------------------------------------------------------------- ------------
----------------------------------------------------------------- ---------------
TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1447.4
10% 141.9
20% 28.4
30% 18.9
40% 9.5
50% 9.5
60% 9.5
70% 9.5
80% 9.5
90% 9.5
8 Item: 11
1449
_________________________________________________________________ ___________
***************************************************************** ***********

SMALL AREA UNIT HYDROGRAPH MODEL
================================================================= ===========
(C) Copyright 1989-2016 Advanced Engineering Software
(aes)
Ver. 23.0 Release Date: 07/01/2016 License ID
1499
Analysis prepared by:

***************************************************************** ***********
---------------------------------------------------------------- ------------
Problem Descriptions:

COSTCO FOOTHILL RANCH
PROPOSED 100 YEAR UNIT HYDROGRAPH

KIMLEY-HORN
---------------------------------------------------------------- ------------
RATIONAL METHOD CALIBRATION COEFFICIENT = 0.90
TOTAL CATCHMENT AREA(ACRES) = 15.65
SOIL-LOSS RATE, Fm,(INCH/HR) = 0.000
LOW LOSS FRACTION = 0.157
TIME OF CONCENTRATION(MIN.) = 8.69

SMALL AREA PEAK Q COMPUTED USING PEAK FLOW RATE FORMULA ORANGE COUNTY "VALLEY" RAINFALL VALUES ARE USED
RETURN FREQUENCY(YEARS) = 100
5-MINUTE POINT RAINFALL VALUE(INCHES) = 0.52
30-MINUTE POINT RAINFALL VALUE(INCHES) = 1.09
1-HOUR POINT RAINFALL VALUE(INCHES) = 1.45
3-HOUR POINT RAINFALL VALUE(INCHES) = 2.43
6-HOUR POINT RAINFALL VALUE(INCHES) = 3.36
24-HOUR POINT RAINFALL VALUE(INCHES) = 5.63
---------------------------------------------------------------- 1 Item: 11
1450
------------
TOTAL CATCHMENT RUNOFF VOLUME(ACRE-FEET) = 6.56
TOTAL CATCHMENT SOIL-LOSS VOLUME(ACRE-FEET) = 0.78
***************************************************************** ***********
TIME VOLUME Q 0. 17.5 35.0 52.5

70.0 (HOURS) (AF) (CFS)
---------------------------------------------------------------- ------------

0.07 0.0000 0.00
Q . . . .

0.21 0.0074 1.24
Q . . . .

0.36 0.0222 1.24
Q . . . .

0.50 0.0371 1.25
Q . . . .

0.65 0.0521 1.26
Q . . . .

0.79 0.0672 1.27
Q . . . .

0.94 0.0824 1.27
Q . . . .

1.08 0.0976 1.28
Q . . . .

1.23 0.1130 1.29
Q . . . .

1.37 0.1284 1.30
Q . . . .

1.52 0.1440 1.30
Q . . . .

1.66 0.1596 1.31
Q . . . .

1.81 0.1754 1.32
Q . . . .

1.95 0.1912 1.33
Q . . . .

2.10 0.2072 1.33
Q . . . .

2.24 0.2232 1.35
Q . . . .

2.39 0.2394 1.35
Q . . . .

2.53 0.2556 1.36
Q . . . .

2.68 0.2720 1.37
Q . . . .

2.82 0.2885 1.38
2 Item: 11
1451
Q . . . .

2.97 0.3051 1.39
Q . . . .

3.11 0.3218 1.40
Q . . . .

3.25 0.3386 1.41
Q . . . .

3.40 0.3555 1.42
Q . . . .

3.54 0.3726 1.43
Q . . . .

3.69 0.3898 1.44
Q . . . .

3.83 0.4071 1.45
Q . . . .

3.98 0.4246 1.46
Q . . . .

4.12 0.4421 1.47
Q . . . .

4.27 0.4599 1.49
Q . . . .

4.41 0.4777 1.49
Q . . . .

4.56 0.4957 1.51
Q . . . .

4.70 0.5138 1.52
Q . . . .

4.85 0.5321 1.53
Q . . . .

4.99 0.5505 1.54
Q . . . .

5.14 0.5691 1.56
Q . . . .

5.28 0.5878 1.57
Q . . . .

5.43 0.6067 1.59
Q . . . .

5.57 0.6257 1.60
Q . . . .

5.72 0.6449 1.61
Q . . . .

5.86 0.6643 1.62
Q . . . .

6.01 0.6839 1.64
Q . . . .

6.15 0.7036 1.65
Q . . . .

6.30 0.7235 1.67
Q . . . .

6.44 0.7436 1.68
Q . . . .

6.59 0.7639 1.71
3 Item: 11
1452
Q . . . .

6.73 0.7844 1.72
Q . . . .

6.88 0.8050 1.74
Q . . . .

7.02 0.8259

1.75 .Q . . . .

7.17 0.8470

1.77 .Q . . . .

7.31 0.8683

1.79 .Q . . . .

7.45 0.8898

1.81 .Q . . . .

7.60 0.9116

1.82 .Q . . . .

7.74 0.9336

1.85 .Q . . . .

7.89 0.9558

1.86 .Q . . . .

8.03 0.9783

1.89 .Q . . . .

8.18 1.0010

1.91 .Q . . . .

8.32 1.0240

1.94 .Q . . . .

8.47 1.0473

1.95 .Q . . . .

8.61 1.0708

1.98 .Q . . . .

8.76 1.0946

2.00 .Q . . . .

8.90 1.1187

2.03 .Q . . . .

9.05 1.1432

2.05 .Q . . . .

9.19 1.1679

2.09 .Q . . . .

9.34 1.1930

2.10 .Q . . . .

9.48 1.2184

2.14 .Q . . . .

9.63 1.2441

2.16 .Q . . . .

9.77 1.2703

2.20 .Q . . . .

9.92 1.2968

2.22 .Q . . . .

10.06 1.3237

2.27 .Q . . . .

10.21 1.3509

2.29 .Q . . . .

10.35 1.3787
4 Item: 11
1453

2.34 .Q . . . .

10.50 1.4068

2.36 .Q . . . .

10.64 1.4354

2.42 .Q . . . .

10.79 1.4645

2.44 .Q . . . .

10.93 1.4941

2.50 .Q . . . .

11.08 1.5243

2.53 .Q . . . .

11.22 1.5549

2.59 .Q . . . .

11.37 1.5862

2.63 .Q . . . .

11.51 1.6180

2.70 .Q . . . .

11.65 1.6505

2.73 .Q . . . .

11.80 1.6836

2.81 .Q . . . .

11.94 1.7175

2.85 .Q . . . .

12.09 1.7540

3.25 .Q . . . .

12.23 1.7958 3.73 .

Q . . . .

12.38 1.8411 3.83 .

Q . . . .

12.52 1.8873 3.89 .

Q . . . .

12.67 1.9346 4.00 .

Q . . . .

12.81 1.9829 4.06 .

Q . . . .

12.96 2.0323 4.20 .

Q . . . .

13.10 2.0830 4.27 .

Q . . . .

13.25 2.1349 4.42 .

Q . . . .

13.39 2.1883 4.50 .

Q . . . .

13.54 2.2432 4.68 .

Q . . . .

13.68 2.2998 4.77 .

Q . . . .

13.83 2.3582 4.99 .

Q . . . .

13.97 2.4186 5.10 .

Q . . . .

14.12 2.4814 5.38 .
5 Item: 11
1454
Q . . . .

14.26 2.5468 5.54 .

Q . . . .

14.41 2.6150 5.86 .

Q . . . .

14.55 2.6863 6.05 .

Q . . . .

14.70 2.7613 6.48 .

Q . . . .

14.84 2.8403 6.73 .

Q . . . .

14.99 2.9244 7.33 .

Q . . . .

15.13 3.0143 7.69 .

Q . . . .

15.28 3.1118 8.60 .

Q . . . .

15.42 3.2183 9.19 .

Q . . . .

15.57 3.3309 9.62 .

Q . . . .

15.71 3.4534 10.84 .

Q . . . .

15.86 3.6106 15.43 .

Q . . . .

16.00 3.8289 21.06 . .

Q . . .

16.14 4.3353 63.54 . . . .

Q .

16.29 4.7910 12.60 .

Q . . . .

16.43 4.9192 8.83 .

Q . . . .

16.58 5.0206 8.11 .

Q . . . .

16.72 5.1111 7.01 .

Q . . . .

16.87 5.1905 6.25 .

Q . . . .

17.01 5.2620 5.69 .

Q . . . .

17.16 5.3274 5.23 .

Q . . . .

17.30 5.3878 4.88 .

Q . . . .

17.45 5.4445 4.59 .

Q . . . .

17.59 5.4979 4.34 .

Q . . . .

17.74 5.5486 4.13 .

Q . . . .

17.88 5.5969 3.94 .
6 Item: 11
1455
Q . . . .

18.03 5.6432 3.78 .

Q . . . .

18.17 5.6831

2.89 .Q . . . .

18.32 5.7170

2.77 .Q . . . .

18.46 5.7495

2.66 .Q . . . .

18.61 5.7807

2.56 .Q . . . .

18.75 5.8109

2.47 .Q . . . .

18.90 5.8400

2.39 .Q . . . .

19.04 5.8681

2.32 .Q . . . .

19.19 5.8954

2.25 .Q . . . .

19.33 5.9219

2.18 .Q . . . .

19.48 5.9477

2.12 .Q . . . .

19.62 5.9728

2.07 .Q . . . .

19.77 5.9972

2.02 .Q . . . .

19.91 6.0210

1.97 .Q . . . .

20.06 6.0443

1.92 .Q . . . .

20.20 6.0670

1.88 .Q . . . .

20.34 6.0892

1.84 .Q . . . .

20.49 6.1110

1.80 .Q . . . .

20.63 6.1323

1.76 .Q . . . .

20.78 6.1532 1.73
Q . . . .

20.92 6.1737 1.69
Q . . . .

21.07 6.1938 1.66
Q . . . .

21.21 6.2135 1.63
Q . . . .

21.36 6.2329 1.60
Q . . . .

21.50 6.2519 1.58
Q . . . .

21.65 6.2706 1.55
7 Item: 11
1456
Q . . . .

21.79 6.2891 1.53
Q . . . .

21.94 6.3072 1.50
Q . . . .

22.08 6.3250 1.48
Q . . . .

22.23 6.3426 1.46
Q . . . .

22.37 6.3599 1.44
Q . . . .

22.52 6.3770 1.42
Q . . . .

22.66 6.3938 1.40
Q . . . .

22.81 6.4104 1.38
Q . . . .

22.95 6.4268 1.36
Q . . . .

23.10 6.4429 1.34
Q . . . .

23.24 6.4589 1.32
Q . . . .

23.39 6.4746 1.31
Q . . . .

23.53 6.4902 1.29
Q . . . .

23.68 6.5055 1.28
Q . . . .

23.82 6.5207 1.26
Q . . . .

23.97 6.5357 1.25
Q . . . .

24.11 6.5505 1.23
Q . . . .

24.26 6.5579 0.00
Q . . . .
---------------------------------------------------------------- ------------
----------------------------------------------------------------- ---------------
TIME DURATION(minutes) OF PERCENTILES OF ESTIMATED PEAK FLOW RATE:
(Note: 100% of Peak Flow Rate estimate assumed to have
an instantaneous time duration)
Percentile of Estimated Duration
Peak Flow Rate (minutes)
======================= =========
0% 1442.5
10% 130.3
20% 26.1
8 Item: 11
1457
30% 17.4
40% 8.7
50% 8.7
60% 8.7
70% 8.7
80% 8.7
90% 8.7
9 Item: 11
1458
15 Costco Foothill Ranch Preliminary Hydrology Report
November 2025
Appendix G –Basin Routing
Calculations
Item: 11
1459
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Friday, 05 / 16 / 2025 Hyd. No. 2
Basin Routing
Hydrograph type = Reservoir Peak discharge = 21.66 cfs
Storm frequency = 2 yrs Time to peak = 15.30 hrs
Time interval = 9 min Hyd. volume = 98,411 cuft
Inflow hyd. No. = 1 - STORM INFLOW Max. Elevation = 101.80 ft Reservoir name = Basin Max. Storage = 1,153 cuft
Storage Indication method used.

4.2 6.3 8.4 10.5 12.6 14.7 16.8 18.9 21.0 23.1
Q (cfs)

0.00 0.00

4.00 4.00

8.00 8.00

12.00 12.00

16.00 16.00

20.00 20.00

24.00 24.00

28.00 28.00
Q (cfs)
Time (hrs)
Basin Routing
Hyd. No. 2 -- 2 Year
Hyd No. 2 Hyd No. 1 Total storage used = 1,153 cuft
Item: 11
1460
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Friday, 05 / 16 / 2025 Hyd. No. 2
Basin Routing
Hydrograph type = Reservoir Peak discharge = 38.97 cfs
Storm frequency = 10 yrs Time to peak = 15.30 hrs
Time interval = 9 min Hyd. volume = 179,678 cuft
Inflow hyd. No. = 1 - STORM INFLOW Max. Elevation = 103.02 ft Reservoir name = Basin Max. Storage = 2,061 cuft
Storage Indication method used.

0.0 2.1 4.2 6.3 8.4 10.5 12.6 14.7 16.8 18.9 21.0 23.1
Q (cfs)

0.00 0.00

10.00 10.00

20.00 20.00

30.00 30.00

40.00 40.00

50.00 50.00
Q (cfs)
Time (hrs)
Basin Routing
Hyd. No. 2 -- 10 Year
Hyd No. 2 Hyd No. 1 Total storage used = 2,061 cuft
Item: 11
1461
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk® Civil 3D® by Autodesk, Inc. v2024 Friday, 05 / 16 / 2025 Hyd. No. 2
Basin Routing
Hydrograph type = Reservoir Peak discharge = 60.09 cfs
Storm frequency = 100 yrs Time to peak = 15.30 hrs
Time interval = 9 min Hyd. volume = 278,422 cuft
Inflow hyd. No. = 1 - STORM INFLOW Max. Elevation = 104.50 ft Reservoir name = Basin Max. Storage = 2,916 cuft
Storage Indication method used.

0.0 2.1 4.2 6.3 8.4 10.5 12.6 14.7 16.8 18.9 21.0 23.1
Q (cfs)

0.00 0.00

10.00 10.00

20.00 20.00

30.00 30.00

40.00 40.00

50.00 50.00

60.00 60.00

70.00 70.00
Q (cfs)
Time (hrs)
Basin Routing
Hyd. No. 2 -- 100 Year
Hyd No. 2 Hyd No. 1 Total storage used = 2,916 cuft
Item: 11
1462
Item: 11
1463
Item: 11
1464
Item: 11
1465
Item: 11
1466
16 Costco Foothill Ranch Preliminary Hydrology Report
November 2025
Appendix H – Hydraulic Calculations
Item: 11
1467
17 Costco Foothill Ranch Preliminary Hydrology Report
November 2025
Appendix I – Kleinfelder Drainage
Report
Item: 11
1468
25003229.001A/LH25R178197 Page 1 of 1 April 4, 2025
© 2025 Kleinfelder www.kleinfelder.com
24411 Ridge Route Dr. Suite 225, Laguna Hills 92653 p | 949.727.4466 f | 949.727.9242 April 4, 2025
Kleinfelder Project No. 25003229.001A
Costco Wholesale
9 Corporate Park
Irvine, California 92606
Attention: Mr. Michael Okuma
AVP Real Estate Development
SUBJECT: Geotechnical Study
Proposed Costco Wholesale Warehouse
26602 Towne Centre Drive
Foothill Ranch, California
CW# 24-1218
Dear Mr. Okuma:

Kleinfelder is pleased to present this report summarizing our geotechnical study for the proposed Costco Wholesale Warehouse located at 26602 Towne Centre Drive in Foothill Ranch, California.

The conclusions and recommendations presented in this report are subject to the limitations presented in Section 7.

We appreciate the opportunity to provide geotechnical engineering services to you on this project.

If you have any questions regarding this report or if we can be of further service, please do not hesitate to contact Brian Crystal 949.727.4466, or Andy Franks, Kleinfelder’s Client Account Manager for Costco at 480.650.4905.

Sincerely,

KLEINFELDER
Hector Marquez, PE Brian E. Crystal, PE, GE
Project Engineer Senior Project Manager
Item: 11
1469
Copyright 2025 Kleinfelder
All Rights Reserved

ONLY THE CLIENT OR ITS DESIGNATED REPRESENTATIVES MAY USE THIS DOCUMENT AND ONLY FOR THE SPECIFIC PROJECT FOR WHICH THIS REPORT WAS PREPARED.
25003229.001A/LH25R178197 Page i of iv April 4, 2025
© 2025 Kleinfelder www.kleinfelder.com

GEOTECHNICAL STUDY

PROPOSED COSTCO WHOLESALE WAREHOUSE
26602 TOWNE CENTRE DRIVE

FOOTHILL RANCH, CALIFORNIA
CW# 24-1218
KLEINFELDER PROJECT NO. 25003229.001A
APRIL 4, 2025
Item: 11
1470
25003229.001A/LH25R178197 Page ii of iv April 4, 2025
© 2025 Kleinfelder www.kleinfelder.com
A Report Prepared for:

Costco Wholesale
9 Corporate Park
Irvine, California 92606
Attention: Mr. Michael Okuma
AVP Real Estate Development

GEOTECHNICAL STUDY

PROPOSED COSTCO WHOLESALE WAREHOUSE
26602 TOWNE CENTRE DRIVE

FOOTHILL RANCH, CALIFORNIA
CW# 24-1218
Hector Marquez, PE
Project Engineer
Brian E. Crystal, PE, GE
Senior Project Manager

KLEINFELDER
24411 Ridge Route Drive, Suite 225
Laguna Hills, California
Phone: 949.727.4466
Fax: 949.727.9242
April 4, 2025
Kleinfelder Project No. 25003229.001A
Item: 11
1471
April 4, 2025 Page 1 of 5
Geotechnical Investigation Summary Checklist for Costco Wholesale Projects
General Information
Costco Real Estate Main Contact: Michael Okuma
Geotechnical Main Contact: Brian Crystal (949.585.3113) Geotechnical Engineer of Record: Kleinfelder
Project Location: 26602 Towne Centre Drive, Foothill Ranch, CA CW#: 24-1218
Warehouse #: N/A
Report Date: April 4, 2025
Consultant Project/Document Number: 25003229.001A/LH25R178197 Addendums (List):

Report Purpose: ☐ Preliminary ☐ Draft ☒ Final ☐ Addendum/Revision Yes
No
or
NA
Describe/ Comments Report
Section
Pre-existing Conditions/Information
Developer provided geotechnical report (describe): ☐ ☒
Pre-existing development (describe) ☒ ☐ Existing commercial development 2.1 Foundation type (describe): ☐ ☒
Performance Issues (describe): ☐ ☒
Environmental Issues (describe) ☐ ☒
Site Grading Records (stripping,compaction test
results,field reports, etc.) ☐ ☒
Typical Building Structural Design Criteria
Other (describe): ☒ ☐ New Costco Warehouse 1.1
Building size (describe): ☒ ☐
160,132-square-foot Costco
Wholesale Warehouse 1.1
Typical wall loading
3 kips / foot* (Metal Buildings) ☐ ☒