5bc._Fortuna_FundingApplicationReport_July_2026-Stamped — Fortuna City Council, September 21, 2026 (part 1 of 2)

Funding Application
Technical Report Update
Version: 03
City of Fortuna
NPDES Compliance Project
July 17, 2026
Funding Application Technical Report Update
Client Name: City of Fortuna
Project Name: NPDES Compliance Project
Document No: 250616123326_e76985f3 Project No: W8Y10900 Date: July 17, 2026 Project Manager: Ted Couch
Revision: 03 File Name: Technical Report
Document History and Status
Revision Date Description Author Checked Reviewed Approved 01 01/20/2023 Draft v1 YC PRR DR TC
02 05/05/2026 Draft v2 YC PRR TC TC
03 07/16/2026 Draft v3 YC PRR TC TC
Jacobs Engineering Inc.
2525 Airpark Drive
Redding, CA 96001-2443
United States
T +1.530.229.3225
F +1.530.243.1654
www.jacobs.com
© Copyright 2026 Jacobs Engineering Inc.. All rights reserved. The content and information contained in this document are the property of the Jacobs group of companies (“Jacobs Group”). Publication, distribution, or reproduction of this document in whole or in part without the written permission of Jacobs Group constitutes an infringement of copyright. Jacobs, the Jacobs logo, and all other Jacobs Group trademarks are the property of Jacobs Group.

NOTICE: This document has been prepared exclusively for the use and benefit of Jacobs Group client. Jacobs Group accepts no liability or responsibility for any use or reliance upon this document by any third party.

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Contents
Acronyms and Abbreviations........................................................................................................................................ vii

1. Introduction ........................................................................................................................................................1-1

1.1 Background Information ....................................................................................................................................1-1

1.2 Existing Process Description.............................................................................................................................1-1

1.3 Effluent Discharge Requirements (Current and Anticipated)..............................................................1-2

1.4 NPDES Compliance Project...............................................................................................................................1-3

1.5 Design Flows and Loadings...............................................................................................................................1-3

1.6 WWTP Upgrades ....................................................................................................................................................1-4

2. Alternatives Evaluation ....................................................................................................................................2-1

2.1 Alternatives Evaluation for Project Definition ...........................................................................................2-1

2.1.1 Economic Evaluation ..............................................................................................................................2-2

2.1.2 Non-Economic Evaluation....................................................................................................................2-4

2.1.3 Total Benefit Scoring for Alternatives..............................................................................................2-5

2.1.4 Recommended Secondary Treatment Alternative .....................................................................2-6

2.2 Alternatives Evaluation for Detailed Design...............................................................................................2-6

3. Treatment Facilities ..........................................................................................................................................3-1

3.1 Automated Flow Equalization ..........................................................................................................................3-1

3.2 Secondary Treatment..........................................................................................................................................3-2

3.2.1 Primary Effluent/Return Activated Sludge Mixing Box ............................................................3-2

3.2.2 Aeration Basins .........................................................................................................................................3-3

3.2.3 Aeration System .......................................................................................................................................3-7

3.2.4 RAS/WAS Pumping .................................................................................................................................3-8

3.2.5 Chemical Feed and Storage.................................................................................................................3-9

3.2.6 WAS and Filtrate Storage Upgrades ..............................................................................................3-11

4. Discipline Design Criteria.................................................................................................................................4-1

4.1 Site Civil.....................................................................................................................................................................4-1

4.1.1 General Description ................................................................................................................................4-1

4.1.2 Codes, Regulations, and Standards ..................................................................................................4-1

4.1.3 Survey ...........................................................................................................................................................4-1

4.1.4 Demolition..................................................................................................................................................4-2

4.1.5 Grading and Drainage Design Criteria .............................................................................................4-2

4.1.6 Site Layout..................................................................................................................................................4-2

4.2 Yard Piping ..............................................................................................................................................................4-3

4.3 Architecture.............................................................................................................................................................4-3

4.3.1 Codes, Regulations, and Standards ..................................................................................................4-3 Funding Application Technical Report Update
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4.3.2 Energy Code Data ....................................................................................................................................4-4

4.3.3 Accessibility and Universal Design....................................................................................................4-4

4.3.4 Design Concepts.......................................................................................................................................4-4

4.3.5 Code Summary..........................................................................................................................................4-5

4.3.6 Chemical Material Storage...................................................................................................................4-5

4.4 Geotechnical ...........................................................................................................................................................4-5

4.4.1 Soil Profile...................................................................................................................................................4-6

4.4.2 Seismic Site Class.....................................................................................................................................4-6

4.4.3 Groundwater..............................................................................................................................................4-6

4.4.4 Bearing Capacity.......................................................................................................................................4-6

4.4.5 Lateral Earth Pressures ..........................................................................................................................4-7

4.4.6 Construction Considerations ...............................................................................................................4-8

4.5 Structural..................................................................................................................................................................4-8

4.5.1 Structural Criteria.....................................................................................................................................4-8

4.5.2 Loads.............................................................................................................................................................4-9

4.5.3 Construction Materials........................................................................................................................4-11

4.5.4 Structural Systems................................................................................................................................4-12

4.6 Process Mechanical...........................................................................................................................................4-13

4.6.1 Codes, Regulations, and Standards ...............................................................................................4-13

4.6.2 Process Equipment Layout and Access ........................................................................................4-13

4.7 Corrosion ...............................................................................................................................................................4-15

4.7.1 Atmospheric Exposure........................................................................................................................4-15

4.7.2 Submerged Exposure ..........................................................................................................................4-16

4.7.3 Buried Exposure.....................................................................................................................................4-16

4.7.4 Hydrogen Sulfide Exposure ..............................................................................................................4-17

4.7.5 Chemical Exposure...............................................................................................................................4-17

4.7.6 Building Systems and Mechanical Equipment ..........................................................................4-17

4.7.7 Electrical and Instrumentation and Controls Systems and Materials ..............................4-17

4.8 Building Services ................................................................................................................................................4-18

4.8.1 Codes, Regulations, and Standards ...............................................................................................4-18

4.8.2 Facility Design Criteria ........................................................................................................................4-18

4.8.3 Building Services Materials ...............................................................................................................4-19

4.8.4 HVAC System Description .................................................................................................................4-19

4.8.5 Energy Compliance ..............................................................................................................................4-19

4.9 Fire Protection.....................................................................................................................................................4-19

4.10 Instrumentation and Control.........................................................................................................................4-19

4.10.1 Existing Instrumentation and Controls....................................................................................4-20 Funding Application Technical Report Update
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4.10.2 New Instrumentation and Controls...........................................................................................4-20

4.11 Electrical ................................................................................................................................................................4-22

4.11.1 Codes, Regulations, and Standards ..........................................................................................4-22

4.11.2 Distribution System.........................................................................................................................4-22

4.11.3 Standby Power Distribution System .........................................................................................4-23

4.11.4 Design Criteria...................................................................................................................................4-23

5. Supervisory Control and Data Acquisition System....................................................................................5-1

5.1 Control System.......................................................................................................................................................5-1

5.2 SCADA System Platform Evaluation..............................................................................................................5-1

5.2.1 PLC Hardware ............................................................................................................................................5-2

5.2.2 HMI Software .............................................................................................................................................5-2

5.3 SCADA Design Standards...................................................................................................................................5-2

5.3.1 In-Plant Communications.....................................................................................................................5-3

5.3.2 Control Logic Programming Standards ..........................................................................................5-6

5.3.3 HMI Graphic Standards..........................................................................................................................5-6

6. Permitting............................................................................................................................................................6-1

7. Construction Cost Estimate .............................................................................................................................7-1

7.1 Cost Estimate Results ..........................................................................................................................................7-1

8. References ...........................................................................................................................................................8-1 Appendices
A New Tagging Standard for Instrumentation and Equipment B Administrative Draft Initial Study and Proposed Mitigated Negative Declaration C Geotechnical Investigation Data Report (SHN)
Tables
1-1. Effluent Limits .......................................................................................................................................................1-2 1-2. Effluent Criteria .....................................................................................................................................................1-3 1-3. Influent Flows and Loadings for 2050.............................................................................................................1-4 2-1. Capital Cost Assumptions ...................................................................................................................................2-2 2-2. O&M Cost Assumptions .......................................................................................................................................2-2 2-3. Capital Cost Estimates for Effluent Criteria 1 ................................................................................................2-3 2-4. O&M Cost Estimates for Effluent Criteria 1 ....................................................................................................2-3 2-5. Life Cycle Cost Factors .........................................................................................................................................2-3 2-6. Life Cycle Cost Estimates for Effluent Criteria 1............................................................................................2-3 2-7. Non-economic Evaluation Criteria and Weighting .......................................................................................2-4 Funding Application Technical Report Update
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2-8. Non-economic Scores – Effluent Criteria 1.....................................................................................................2-5 2-9. Non-economic Weighted Scores – Effluent Criteria 1..................................................................................2-5 2-10. Project Costs ........................................................................................................................................................2-7 3-1. Design Criteria of Existing Influent Flow Equalization Pond......................................................................3-2 3-2. Flow Equalization Pump Sizing .........................................................................................................................3-2 3-3. Process Sizing Assumptions...............................................................................................................................3-3 3-4. Projected MLE Process Performance at the 2050 MMWW Condition ......................................................3-4 3-5. Results from the State Point Analysis for the Secondary Clarifiers..........................................................3-5 3-6. Process Design Criteria for Aeration Basins ...................................................................................................3-6 3-7. Aeration Basin Sizing ...........................................................................................................................................3-6 3-8. Aeration Basin Associated Equipment.............................................................................................................3-6 3-9. Air Demands...........................................................................................................................................................3-7 3-10. Aeration System Equipment............................................................................................................................3-8 3-11. Blower Equipment Design Criteria .................................................................................................................3-8 3-12. Design Criteria for RAS/WAS Pumps .............................................................................................................3-9 3-13. RAS Pump Sizing ................................................................................................................................................3-9 3-14. WAS Pump Sizing ...............................................................................................................................................3-9 3-15. Design Criteria for Magnesium Hydroxide System ................................................................................. 3-10 3-16. Chemical Metering Pump and Storage Sizing.......................................................................................... 3-10 3-17. WAS Storage Equipment Sizing ................................................................................................................... 3-12 3-18. Filtrate Storage Equipment Sizing .............................................................................................................. 3-12 3-19. WAS and Filtrate Storage Tanks Blower Equipment Design Criteria .................................................. 3-12 4-1. Hazardous Material Requirements (Outdoor Storage Control Area) .......................................................4-5 4-2. Lateral Earth Pressure Criteria for Buried Structures ...................................................................................4-7 4-3. Design Criteria for Live Loads at the Aeration Basin Platform ..................................................................4-9 4-4. Design Criteria for Snow Loads..........................................................................................................................4-9 4-5. Design Criteria for Wind Loads ....................................................................................................................... 4-10 4-6. Design Criteria for Seismic Load .................................................................................................................... 4-10 4-7. Construction Materials for Proposed Facilities........................................................................................... 4-11 4-8. Design Conditions for Indoor Spaces ............................................................................................................ 4-18 4-9. Equipment Utilization Voltages ..................................................................................................................... 4-23 4-10. Demand Factors............................................................................................................................................... 4-24 7-1. Estimate Summary for City of Fortuna WWTP ...............................................................................................7-1 Funding Application Technical Report Update
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Figures
1-1. Fortuna WWTP Process Flow Diagram Schematic.........................................................................................1-2 2-1. Summary of Benefit to Normalized NPV Cost for the Effluent Criteria 1 Alternatives ........................2-6 3-1. Layout of the WAS Storage Tank and Filtrate Storage Tank ................................................................... 3-11 4-1. Existing Standing Seam Metal Roof (Digester Building) ............................................................................4-4 5-1. Logical and Conceptual Network Frameworks ..............................................................................................5-4 5-2. Representation of SCADA Environment Separation from Enterprise Systems and Internet .............5-5 5-3. Collapse Core OT Network ..................................................................................................................................5-6 Funding Application Technical Report Update
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Acronyms and Abbreviations
°C degree(s) Celsius
°F degree(s) Fahrenheit
ACI American Concrete Institute
ADM Aluminum Design Manual
ANSI American National Standards Institute
ASCE American Society of Civil Engineers
ASME American Society of Mechanical Engineers
ASTM ASTM International
AWG American wire gauge
BOD5 5-day biological oxygen demand
BODR Basis of Design Report
CBC California Building Code
C&D construction and demolition
CPT cone penetrometer test
DO dissolved oxygen
E+H Endress and Hauser AG
FEB flow equalization basin
ft foot(feet)
ft2square foot(feet)
gpm gallon(s) per minute
H2S hydrogen sulfide
HMI human-machine interface
HOA hand-off-auto
hp horsepower
HVAC heating, ventilation, and air conditioning
IACS industrial automation and control systems
ICEA Insulated Cable Engineers Association
ISA Instrument Society of America
lb/d pound(s) per day
LCP local control panel
MCC motor control center
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mgd million gallon(s) per
MLE Modified Ludzack-Ettinger
MLR mixed liquor return
MLSS mixed liquor suspended solids
MMWW maximum month wet weather
NAVD88 North American Vertical Datum of 1988
NEC National Electrical Code
NEMA National Electrical Manufacturers Association
NFPA National Fire Protection Association
NPDES National Pollutant Discharge Elimination System
O&M operations and maintenance
OT operational technology
PE primary effluent
pcf pound(s) per cubic foot
psf pound(s) per square foot
psi pound(s) per square inch
PLC programmable logic controllers
PVC polyvinyl chloride
RAS return activated sludge
Regional Board North Coast Regional Water Quality Control Board SCADA Supervisory Control and Data Acquisition
SLR solids loading rate
SOR surface overflow rate
SPA state point analysis
SRT solids retention time
THW thermoplastic heat and water-resistant
TP total phosphorus
UL Underwriters Laboratory
VFD variable frequence drive
WAS waste activated sludge
WW wet weather
WWTP Wastewater Treatment Plant
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1. Introduction
This Technical Report Update summarizes the various design upgrades at the City of Fortuna’s (City) Tom Cook Memorial Wastewater Treatment Plant (WWTP). This report comprises information from the detailed design phase of the National Pollutant Discharge Elimination System (NPDES) Compliance Project (Project). The report has been developed by Jacobs on behalf of the City to support its Clean Water State Revolving Fund application.

1.1 Background Information
The Tom Cook Memorial Wastewater Treatment Plant (WWTP) is at 180 Dinsmore Drive in Fortuna, Humboldt County, California. Owned and operated by the City of Fortuna (City), this facility serves a population of approximately 12,500, which includes residential, commercial, and institutional users in the City.

1.2 Existing Process Description
The WWTP facility is divided into a liquids treatment system and solids treatment system. The liquids treatment system consists of the following:
▪ Pretreatment at headworks
▪ Influent pump station
▪ Primary clarification
▪ Secondary biological treatment with partial nitrification (based on the interim NPDES permit) ▪ Disinfection
The solids treatment system consists of the following:
▪ Thickening
▪ Anaerobic digestion
▪ Dewatering
▪ Composting
Primary sludge is thickened in the primary clarifiers, and waste activated sludge (WAS) from secondary treatment is thickened over a gravity belt thickener before being pumped to the digester. The WWTP operates one mesophilic anaerobic digester. The digested sludge is dewatered using a belt filter press.

The dewatered biosolids are then sent to the composting facility to produce Class A biosolids. Filtrate from the gravity belt thickener and belt filter press can be returned back either to primary clarifiers or aeration basins for further treatment. Figure 1-1 shows a schematic process flow diagram of the WWTP.

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Figure 1-1. Fortuna WWTP Process Flow Diagram Schematic

1.3 Effluent Discharge Requirements (Current and Anticipated) The WWTP currently operates under NPDES Permit CA0022730 Order No. R1-2017-0005. The permit expired on October 30, 2022, and is currently under administrative extension while the permit application is being renewed. The permit introduced interim and final limits on nutrients, specifically ammonia and nitrate as shown in Table 1-1.

These limits were to be reduced to the final values once the upgrades to the WWTP were complete or December 31, 2024, whichever came first, in accordance with Time Schedule Order R1-2017-0026 issued by the North Coast Regional Water Quality Control Board (Regional Board). This deadline has been further extended to December 31, 2027, to meet the requirements of the Time Schedule Order.

Table 1-1. Effluent Limits
Parameter
Interim Effluent Limits Final Effluent Limits
Average Monthly Maximum Daily Average Monthly Maximum Daily Ammonia 9.4 mg-N/L – 3.6 mg-N/L 9.6 mg-N/L
Nitrate 32 mg-N/L – 10 mg-N/L –
mg-N/L = milligrams per liter Nitrogen
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While the City must meet the above effluent limits, there have been indications from the Regional Board that the City may be subject to even more stringent nutrient limits in the future, including for phosphorus.

It is possible that more stringent limits may be required of all dischargers to the Eel River, or the City may be required to achieve lower limits to continue their current practice of summertime discharge to their percolation ponds.

Given the uncertainties with the nutrient limits, Jacobs developed two different effluent criteria for nitrogen and phosphorus. Effluent Criteria 1 is based on the NPDES permits for ammonia and nitrate and does not include phosphorus. Effluent Criteria 2 is more stringent for nitrogen and includes a limit for phosphorus. The limits for both effluent criteria are summarized in Table 1-2. Effluent Criteria 1 are the basis of design for the Project, with the ability to expand the WWTP to meet Effluent Criteria 2, if effluent limits become more stringent in the future.

Table 1-2. Effluent Criteria
Criteria Ammonia Nitrate Total Nitrogen
Total
Phosphorus
Effluent Criteria 1 <1 mg-N/L 10 mg-N/L 12 mg-N/L –
Effluent Criteria 2 <1 mg-N/L 1 mg-N/L 3 mg-N/L 0.45 mg-P/L mg-N/L = milligrams per liter Nitrogen
mg-P/L = milligrams per liter Phosphorus

1.4 NPDES Compliance Project
The City will be implementing the Project for the following reasons:
▪ Comply with new permit requirements
▪ System reliability and redundancy
▪ Repair or upgrade obsolete equipment
▪ Energy efficient system
▪ Reduce reliance on fossil fuels
This Project will upgrade the secondary treatment processes to include enhanced biological nutrient removal (BNR) by modifying the process configuration to a Modified Ludzack-Ettinger process. Other upgrades include automation of the flow equalization system, new automatic dissolved oxygen control system and motorized inlet valves for the blowers for energy efficiency. The City will also be upgrading the supervisory control and data acquisition (SCADA) system as part of this Project, as several components have reached their end of useful life and are experiencing repeated failures. The upgrades will optimize and enhance the treatment efficiency thus improving the effluent quality prior to surface water discharge.

1.5 Design Flows and Loadings
The design flows and loads were developed in the Project Definition Report (Jacobs 2025). Because the WWTP has different effluent discharge points, the projections have been split to show dry weather and wet weather (WW) conditions separately. Table 1-3 summarizes the design flows and loads for 2050 used in this Project. For the biological process sizing, the maximum month wet weather (MMWW) condition is used. MMWW flows and loads are higher than the maximum month dry weather conditions, and combined with lower water temperatures, results in a larger bioreactor volume to accommodate the slower biomass growth.

The projected peak hourly flow to the WWTP is estimated to be 7.6 million gallons per day (mgd).

However, any flows beyond 4 mgd will be diverted to the flow equalization basin (FEB) after the influent Funding Application Technical Report Update
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pump station. Equipment sizing based on hydraulics will be evaluated whether the hydraulics are upstream or downstream of the flow diversion to the FEB.

Table 1-3. Influent Flows and Loadings for 2050
Parameter
Dry Weather Wet Weather
Average
Maximum
Month Average
Maximum
Month
Flow, mgd 1.19 1.25 1.87 3.13
Chemical Oxygen Demand, lb/d 8,328 9,201 10,264 13,944
BOD5, lb/d 3,996 4,382 4,887 6,640
Total Suspended Solids, lb/d 3,709 4,574 5,579 7,910
Volatile Suspended Solids, lb/d 3,153 3,888 4,742 6,723 Ammonia-Nitrogen (NH3-N), lb/d N 337 372 343 467
Total Kjeldahl Nitrogen, lb/d N 477 527 558 758
Total Phosphorus (TP), lb/d P 74 82 74 151
Alkalinity, mg CaCO3 per Liter 260 150
Average Influent Temperature, °C 23 13
Bold indicates the design flows and loadings used in this Project. °C = degree(s) Celsius
BOD5 = 5-day biological oxygen demand
CaCO3 = calcium carbonate
lb/d = pound(s) per day
mg = milligram(s)
N = nitrogen
NH3-N = ammonia-nitrogen
P = phosphorous
TP = total phosphorous

1.6 WWTP Upgrades
The primary driver of this Project is to provide a treatment system that will comply with the Effluent Criteria 1 nutrient limits. The upgrades at the WWTP include the following:
▪ Abandon existing aeration basins and add new aeration basins. This is to convert the existing partial nitrification process to a nitrification-denitrification process based on the Modified Ludzack-Ettinger (MLE) process configuration.
▪ Blowers at a new blower facility and removal of existing blowers ▪ Replacement of existing return activated sludge (RAS) and WAS pumps ▪ Lining of existing flow equalization pond (previously called Pond 1) ▪ Automation of the existing flow equalization system.
- Addition of a flow equalization pump station to transfer flow between FEB and primary treatment. ▪ Chemical storage facility for alkalinity
▪ Primary effluent (PE)/RAS mixing box
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▪ WAS storage tank and filtrate storage tank rehabilitation and new blowers associated with these tanks ▪ Complete replacement of supervisory control and data acquisition (SCADA) system for entire WWTP.

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2. Alternatives Evaluation
This section summarizes the alternatives evaluation conducted to select a secondary treatment process alternative to meet NPDES compliance requirements. This section also summarizes the alternatives evaluation conducted during early phases of detailed design to determine the implementation of the selected process.

2.1 Alternatives Evaluation for Project Definition
The Project Definition Report (Jacobs 2025) discusses several alternatives to meet Effluent Criteria 1 as well as Effluent Criteria 2. Various alternatives were presented to the City and an initial screening was conducted based on fatal flaws. A shortlist of alternatives was developed after the initial screening. The list of alternatives considered include:
• Suspended Growth Processes
o Modified Ludzack-Ettinger (MLE)
o Four-Stage Bardenpho
o AeroMod Sequox – Not included for further evaluation since it’s a proprietary process that would lead to sole-sourcing situation with no added performance benefits • Fixed Film Processes
o Integrated Fixed-Film Activated Sludge (IFAS)
o Membrane Aerated Biofilm Reactor (MABR)
o Mobile Organic Biofilm (MOB) – Not included since MOB is relatively new and there are not many installations in the United States using it
• Membrane Processes
o Membrane Bioreactor (MBR) – Not included for further evaluation because of concerns over the increased O&M requirements
The alternatives that were evaluated to meet the current effluent limits and potential future limits included the following:
▪ Suspended growth - MLE
▪ Fixed-film growth – IFAS and MABR
Each nitrogen removal alternative was evaluated using both economic and non-economic factors.

Section 2.1 provides a summary of the capital, O&M, and life cycle costs for each alternative evaluated for Effluent Criteria 1 and Effluent Criteria 2. For the non-economic criteria, the City provided a weighting for each non-economic factor during the workshop held on November 3, 2023. The scores for the noneconomic criteria for each alternative in Effluent Criteria 1 and Effluent Criteria 2 were then completed by the City in the second workshop held on April 26, 2024.

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2.1.1 Economic Evaluation
The total capital cost for building new facilities or retrofitting existing facilities includes construction cost, additional project cost markups, contractor markups, and non-construction cost. The assumptions for estimating the total capital cost are summarized in Table 2-1.

Table 2-1. Capital Cost Assumptions
Parameter Value
Class of Cost Estimate
American Association of Cost Estimators
Class 5
-50% to 100% Error Range
Equipment/Facility Costs Vendor Quotes or from Jacobs
Proprietary Cost Estimating Software
Additional Project Cost (includes sitework, yard piping, electrical, and instrumentation and controls) 18%
Contractor Markups (overhead, profit, bonds/insurance and contingency) 57.5%
Local Adjustment Factor (overall total project factor for translating total cost of project elements from one geographic location to another) 13% Non-construction Cost (engineering, permitting, services during construction) 20%
The O&M costs are annual costs associated with maintaining and operating the WWTP assets. The cost assumptions used in the development of the O&M costs are summarized in Table 2-2. The chemical costs were obtained from potential suppliers, and the unit power cost was provided by the City. It was assumed that no additional WWTP operators will be required for any of the alternatives. The O&M cost breakdown includes equipment power, chemicals, maintenance, repair and replacement, and additional items.

Additional items indicate costs associated with maintenance, repair, and replacement of overall site components of each facility.

Table 2-2. O&M Cost Assumptions
Parameter Value
Sodium hydroxide (supplemental alkalinity, 50% solution) $3.83 per gal (or) $0.30 per lb MicroC (supplemental carbon) $3.78 per gal
Power $0.18 per kilowatt hour
Equipment Maintenance and Repair Cost 2% of project capital cost

2.1.1.1 Capital Cost Estimate
The capital cost associated with each alternative for Effluent Criteria 1 is summarized in Table 2-3.

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Table 2-3. Capital Cost Estimates for Effluent Criteria 1 Parameter
MLE IFAS (Veolia) MABR
Retrofit New Retrofit Retrofit
Project Cost before Markups $16M $19M $16M $15.6M
Capital Cost $43.5M $51.5M $44M $43M
M = million dollars

2.1.1.2 O&M Cost Estimate
The O&M cost associated with each alternative for Effluent Criteria 1 is summarized in Table 2-4.

Table 2-4. O&M Cost Estimates for Effluent Criteria 1
Cost MLE (Retrofit) MLE (New) IFAS (Veolia) MABR
Annual O&M $1.20M $1.25M $1.60M $1.25M

2.1.1.3 Life Cycle Cost Estimate
Estimating and comparing the monetary costs of proposed alternatives were done using the net present value (NPV) analysis. The life cycle cost analysis converts all expenditures that occur during the project into a single equivalent present value sum at the time of the analysis, allowing for a like-to-like comparison. For each alternative, the capital costs and O&M costs were used to derive the NPV over a 20-year period. The factors used in the estimation of the NPV for each alternative are summarized in Table 2-5.

Table 2-5. Life Cycle Cost Factors
Parameter Value
Inflation Rate 3.00%
Discount Rate 5.00%
Evaluation Term 20 years
Table 2-6 lists the life cycle cost for the proposed alternatives to comply with Effluent Criteria 1.

Table 2-6. Life Cycle Cost Estimates for Effluent Criteria 1 Cost Type MLE (Retrofit)a MLE (New)
b
IFASc MABR
Construction Cost $36M $43M $36.5M $35.5M
Annual O&M Cost $1.20M $1.25M $1.60M $1.25M
Total Life Cycle Cost
(20-year) $55.5M $63M $63M $56M
a MLE with existing reactors plus an additional reactor b Existing aeration basins are abandoned. Construct new aeration basins. c IFAS system from Veolia
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2.1.2 Non-Economic Evaluation
The relative importance of the non-economic factors was used to weight criteria when evaluating the alternatives for Effluent Criteria 1. Each factor was weighted based on importance from highest to lowest, where 10 is the highest and 1 is the lowest. The weighting percentages were then determined by dividing the weighting score for each factor by the total weighting score.

Table 2-7 provides a brief description of each non-economic factor and the associated weighting score.

The weighting was provided by the City. Based on the scoring, the permit compliance and system reliability were ranked the most important, while the chemical usage and maturity of treatment technology were ranked comparatively lower.

Table 2-7. Non-economic Evaluation Criteria and Weighting Factor Description Weighting
Weighting
Percentage
Adaptability/
Phasing
How easily can the process/alternative be upgraded for
future conditions or requirements (e.g., changes to flows, loads, future regulations, co-digestion)
How easily can the alternative be phased in to meet the City’s needs over time in an economical time frame
9 18.4%
Constructability/
Footprint
What would be the extent of modifications to the existing processes resulting from the alternative. How large of a footprint is required.
8 16.3%
Chemical Usage
Does the alternative use lesser or greater number and
quantity of chemicals.

Is the supply chain reliable.

Any operational hazards (e.g. methanol, caustic soda).
7 14.3%
Permit Compliance/
System Reliability
How reliably will the alternative meet permit and other regulatory requirements.

If part or all of the process fails, how impactful would the consequences be. Does the system minimize risks.
10 20.4%
Maturity of
Treatment
Technology
Does the alternative use a proven process (in terms of
years) since the process or alternative was developed. What is the number of successful installations Are there
equivalent sized installations and known reliability of the alternative in the industry.
7 14.3%
Ease of O&M
How easily can each alternative be operated/automated to simplify O&M monitoring and management.

How maintainable would the system be.

How many operators would be needed. Would training or
expertise be needed.
8 16.3%
During the alternatives evaluation workshop held on April 26, 2024, City staff determined the scoring for the non-economic criteria developed in Table 2-7 for the proposed alternatives for Effluent Criteria 1 and Effluent Criteria 2. The scoring was based on a minimum of 1 and maximum of 10, where 10 indicates most favorable and 1 indicates least favorable among the alternatives. The raw scores and weighting for Funding Application Technical Report Update
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each factor from Table 2-7 were used to determine the weighted score for comparison. The total benefit for an alternative is the sum of individual criterion scores multiplied by their respective weightings to produce a weighted benefit score.

Table 2-8 and Table 2-9 present the raw scores and weighted scores for all the alternatives in Effluent Criteria 1.

Table 2-8. Non-economic Scores – Effluent Criteria 1
Criteria MLE (Retrofit)
MLE
(Greenfield) IFAS (Veolia) MABR
Adaptability/ Phasing 7 7 7 8
Constructability/ Footprint 6 3 4 6
Chemical Usage 5 5 5 7
Permit Compliance/ System
Reliability 9 9 9 9
Maturity of Treatment
Technology 10 10 8 3
Ease of O&M 9 9 6 6
Table 2-9. Non-economic Weighted Scores – Effluent Criteria 1 Criteria
Criteria
Weighting MLE (Retrofit) MLE (Greenfield)
IFAS
(Veolia) MABR
Adaptability/ Phasing 18.4% 1.29 1.29 1.29 1.47
Constructability/
Footprint 16.3% 0.98 0.49 0.65 0.98
Chemical Usage 14.3% 0.71 0.71 0.71 1.00
Permit Compliance/
System Reliability 20.4% 1.84 1.84 1.84 1.84
Maturity of Treatment
Technology 14.3% 1.43 1.43 1.14 0.43
Ease of O&M 16.3% 1.47 1.47 0.98 0.98
Weighted Score 7.71 7.22 6.61 6.69

2.1.3 Total Benefit Scoring for Alternatives
The comparison of alternatives was conducted using a benefit-to-cost ratio. The benefit-to-cost rating of an alternative was determined by dividing the total weighted benefit score by its normalized NPV cost. The normalized NPV cost for each alternative is the NPV cost of that alternative divided by the lowest NPV cost among the alternatives for that effluent criterion.

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The bar graph for each alternative illustrates the weighted score, along with each category from which the score was earned. The green line represents the ratio of benefit to normalized NPV cost.

Figure 2-1 shows the benefit-to-cost ratio and the total weighted score for each alternative evaluated for Effluent Criteria 1. The MLE (retrofit) has the highest non-economic weighted benefit and the highest benefit-to-cost ratio among Effluent Criteria 1 alternatives.

Figure 2-1. Summary of Benefit to Normalized NPV Cost for the Effluent Criteria 1 Alternatives

2.1.4 Recommended Secondary Treatment Alternative
The results of the nitrogen removal alternatives evaluation for Effluent Criteria 1 were presented to the City on April 26, 2024. The existing secondary treatment will be upgraded to meet Effluent Criteria 1, which is based on the NPDES permit limits and, when required, will expand the secondary treatment to meet Effluent Criteria 2. The benefit -to-cost analysis showed that the conventional MLE had the highest score for Effluent Criteria 1. The City has selected MLE as the preferred alternative for the secondary treatment upgrades.

2.2 Alternatives Evaluation for Detailed Design
As the final benefit to cost ratios for the two MLE options (retrofit or new basins) were relatively close, Jacobs conducted a further evaluation during the detailed design phase, to confirm the optimal design configuration. The following alternatives were evaluated and presented as part of the Aeration Basin Configuration and Equipment Selection Workshop, held on March 18, 2025:

1. Aeration System Design
a. Aeration Basin Configuration
i. Option 1 – Reconfiguring existing aeration basins and construct a fourth aeration basin ii. Option 2 – Abandon existing reactors and build two new reactors b. Seismic Retrofits of existing reactors should be considered or not Funding Application Technical Report Update
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c. Blower Alternatives
d. Mixer Alternatives
e. Diffuser Alternatives
A second workshop was held with the City on April 29, 2025. This workshop focused on the aeration basins design, whether to retrofit existing aeration basins and build one new reactor (Option 1) or construct new aeration basins and abandon the existing ones (Option 2). These two options were compared since the preliminary cost estimate indicated the costs to be within the range of accuracy. A seismic analysis of the baffle wall design in the existing aeration basins was analyzed for Option 1. The results showed that any modifications will require the existing aeration basins to be retrofitted to the current seismic code. The available options for seismic retrofit would either reduce the volume of existing basins or reduce the sidewater depth impacting the efficacy of aeration.

A summary of project cost information is provided on Table 2-10.

Table 2-10. Project Costs
Parameter Option 1 – Construct AB4 and Reuse
Existing Basins*
Option 2- Construct New
Aeration Basins*
Capital Cost a(median) $19.7M $22.00M
Annual O&M b $0.31M $0.16M
O&M (NPV) $4.50M $2.30M
Total NPV (23-yr) $24.20M $24.30M
a Class 5 Construction Cost
b Counts anoxic mixers/MLR/Blower power demands, aeration system repair/replacement, blower repair/replacement *Based on 2025 dollars
The City selected Option 2––abandoning their existing aeration basins and constructing two new aeration basins––to meet Effluent Criteria 1. Although the capital cost for Option 2 is higher than Option 1, the operations and maintenance (O&M) costs were much lower because of lower maintenance requirements and more energy efficiency in Option 2. Additionally, the new aeration basins will be built to the current seismic code and would be more seismically resilient. The City has also selected a hyperbolic mixer to be used in the anoxic zone and submerged membrane disc diffusers to be used in the aerobic zones. Positive displacement blowers were selected as the preferred blower technology.

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3. Treatment Facilities
Section 3 provides details on the treatment facilities being constructed or upgraded as part of this project.

3.1 Automated Flow Equalization
The flow equalization includes the following treatment features:
▪ FEB
▪ Flow equalization pump station
These features equalize flows of screened and degritted wastewater exceeding 4 mgd to minimize the capacity of downstream processes. Influent flow equalization is provided to divert peak flows to minimize the hydraulic capacity of treatment processes downstream of headworks.

At the Headworks facility, upstream of screening, excessive flows will be diverted to the FEB. Flow diversion will occur at the existing 30-inch wide slide gate that will discharge flow to the FEB via an existing 24-inch raw sewage pipe. This slide gate is located upstream of the mechanical bar screen. Flow will be controlled by the addition of an actuator to this slide gate. Once the plant incoming flow is at or exceeds 4 mgd, the slide gate will be lowered. A flow meter to the primary clarifier splitter box will be added and once flow reaches less than 4 mgd, the slide gate will be raised. The FEB pump station will start when the flow going to the primary clarifier splitter box is less than 4 mgd and the basin is at the minimum level to start the pumps to equalize the flow to 4 mgd.

The existing flow equalization is manually operated, which includes a gate upstream of the screens to divert flows to the FEB. The objective of this design is to automate the system. Flow exceeding a certain flow rate that are equalized is defined as the “equalized flow threshold.” Setting the equalized flow threshold low results in a larger equalization volume that would be used more frequently, which allows for smaller treatment processes. Setting the equalized flow threshold high results in smaller equalization that is used less frequently and requires larger downstream processes. No equalization means all treatment processes need to be sized to treat peak flows.

To define both the equalization flow threshold, several idealized storm scenarios were used to simulate the flow to the WWTP and determine the capacity of the existing system and FEB. Using the simulation results and the historical hourly flow data into the plant, the City selected a peak hourly equalization flow threshold of 4 mgd into the WWTP. The 4 mgd equalization flow threshold was maintained for the 2050 condition. This control variable can be set to a different number by the operator, with the maximum being 4 mgd.

Key elements of influent flow equalization include the following:
▪ System automation, which will include flow control valves and flowmeters ▪ Flow-to-FEB from the influent pump station
▪ Flow-to-flow equalization pump station from the flow equalization pond by gravity ▪ Flow to the primary clarifier splitter box from the flow equalization pump station ▪ Uncovered odor control not required (washdown expected after use) ▪ Accessible from above with hose bibs for washdown
▪ Motorized valves to automate the flow equalization system Table 3-1 shows the design basis of the existing flow equalization pond.

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Table 3-1. Design Criteria of Existing Influent Flow Equalization Pond Parameter Value Units
Volume 5.53 MG
Depth 13 ft
Type Lagoon -
Equalization Threshold to
Downstream Processes 4 mgd
- = not applicable
ft = foot(feet)
MG = million gallons
Table 3-2 shows the sizing of the new flow equalization pump station. The hydraulics were calculated using AFT Fathom to model the low-level and high-level conditions of the FEB. Three scenarios were modeled with a low-level, low-capacity; low-level, high-capacity; and high-level, high-capacity to size the pump station. The pump station was determined to have a maximum capacity of 3.3 mgd to equalize to 4 mgd with a low influent plant flow of 0.7 mgd from the load projections, which totals to three duty pumps at 760 gallons per minute (gpm) with one standby pump. The pump station was determined to have a minimum capacity of 0.5 mgd based on the minimum flow speed of the raw sewage.

Table 3-2. Flow Equalization Pump Sizing
Parameter Value Units
Number of pumps 3 (2 Duty, 1 Standby) -
Pump type Submersible Pumps -
Pump capacity 370–740 gpm
TDH 35 max, 15 min, 20 average ft
Motor size 20 hp
hp = horsepower
TDH = total dynamic head

3.2 Secondary Treatment
Secondary treatment at the WWTP encompasses biological treatment using an activated sludge process and settling out the sludge using a clarification process. A distribution box collects and mixes the PE and RAS and then distributes the blended influent between the aeration basins. Organic constituents are biologically broken down, and the ammonia is converted to nitrate and then nitrogen gas by the activated sludge process. The suspended growth biological flocs of the activated sludge process are called mixed liquor suspended solids (MLSS). The MLSS is separated by gravity settling in the secondary clarifiers.

Secondary effluent from the clarifiers is then sent to the disinfection process. Settled sludge is pumped back to the aeration basins using the RAS pumps. A portion of the sludge is wasted out as WAS, which is sent to the solids treatment for further processing.

3.2.1 Primary Effluent/Return Activated Sludge Mixing Box The existing PE/RAS box will be abandoned, and a new PE/RAS box will be constructed in this Project to split the flows to the two new aeration basins. This distribution box will receive the PE from the primary clarifiers as well as the RAS from the RAS pump station.

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The mixing box will share a wall with the influent distribution channel of the aeration basins. PE and RAS will mix in a common volume before being distributed to the aeration basins through respective weirs.

Alkalinity control by the addition of magnesium hydroxide will occur in the common volume as well. The structure will include space for distribution to a future third aeration basin.

3.2.2 Aeration Basins

3.2.2.1 Process Modeling Results
The model for the WWTP upgrades was constructed using SUMO, a commercially available, whole-plant, dynamic simulator software by Dynamita. Model calibration and validation were completed in the Project Definition Report (Jacobs 2025). The Project Definition Report evaluated several alternatives for the nutrient removal, and the City selected MLE process as the preferred alternative to move forward for the detailed design. During detailed design, the process model was used to optimize the aeration basin performance and determine the air demands and secondary clarifier performance. This section summarizes the results of the process model for 2050 MMWW, which was selected as the design year.

The 2050 MMWW influent flows and loads described in Table 1-3 were used to determine the aeration basin volume and air demand. Effluent criteria 1 described in Table 1-2 were used for nitrogen limits. The process sizing assumptions are summarized in Table 3-3..

Table 3-3. Process Sizing Assumptions
Criteria Value Comments
Process Configuration MLE
Primary Clarification TSS Removal
Performance 60%
Zone Fractions 15/85 Anoxic volume / aerobic volume
Minimum Sustained Temperature 13°C
Target MLSS 3,555 mg/L At maximum month conditions
Aerobic SRT 10 days Including a nitrification safety factor of 2.5 MLR Rate 300% Percentage of bioreactor influent flow
SVI 150 mL/g
RAS Rate 80% Percentage of bioreactor influent flow
MLSS = mixed liquor suspended solids
SRT = solids retention time
SVI = sludge volume index
TSS = total suspended solids
The projected treatment performance is summarized in Table 3-4. .

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Table 3-4. Projected MLE Process Performance at the 2050 MMWW Condition Criteria Value Comments
Total Bioreactor Volume 1.2 MG
MLSS 3,555 mg/L Maximum MLSS design criteria
Effluent BOD5 3.2 mg/L
Effluent TSS 10 mg/L Assumed (model input)
Effluent NH3-N 0.41 mg N/L
Effluent NO3-N 4.0 mg N/L
Effluent pH 6.7
Effluent Total Nitrogen (TN-N) 6.1 mg N/L
Effluent Total Phosphorus (TP-P) 3.7 mg P/L
Primary Sludge Flow Rate 25,419 gpd
Primary Sludge TS 4,666 lb/d At 2.2% TS
WAS Flow Rate 41,528 gpd
WAS TS 2,768 lb/d Wasted from RAS to solids treatment
Total Aeration Demand 1,424 scfm
Supplemental Alkalinity Demand 100 gpd Assumed Magnesium Hydroxide slurry (60% concentration)
gpd = gallon(s) per day
scfm = standard cubic foot per minute
TS = total solids
WAS = waste activated sludge
The performance of the existing secondary clarifiers was evaluated using the SUMO process model along with Jacobs PClarifier tool. PClarifier uses solid flux theory and state point analysis (SPA) to determine the limiting conditions on the clarifier (solids or hydraulic loading).

The two key parameters to determine the clarifier capacity are surface overflow rate (SOR) and solids loading rate (SLR). Typically, the design SOR at the peak flow is set to be 1,200 gpd per square foot (ft2) or less (WEF 2018). For the SLR, it is typical for newly constructed and well-designed clarifiers to be sized so that the design SLR is below 90% of the theoretical maximum to account for the collector inefficiencies in actual installations. For older and shallow clarifiers like those in operation at the WWTP, Jacobs typically set the effective SLR limits at approximately 70% of the theoretical limits. The calculations for SOR and SLR are derived from the SPA.

As shown in Table 3-5, the projected SLR at design conditions with two existing secondary clarifiers in service would exceed the effective limit of 70% at the design condition, indicating that an additional secondary clarifier will be required for the design conditions. Whereas with 1.2 MG total reactor volume, the two secondary clarifiers are projected to be at capacity when the MMWW flow is around 3 mgd and influent BOD5 is 6,000 lb/d. According to the projections defined in the Project Definition Report (Jacobs 2025), this will occur in 2047. Therefore, the construction of the third secondary clarifier will be deferred until the actual loading increases near the projected loading. With three secondary clarifiers, the SLR at the design condition is 65% of the theoretical limit, indicating three clarifiers will be sufficient for the 2050 MMWW conditions.

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Table 3-5. Results from the State Point Analysis for the Secondary Clarifiers Output Parameter
2050 MMWW (Two
Secondary Clarifiers)
2050 MMWW (Three
Secondary Clarifiers) Comments
SOR 552 gpd/ft2 368 gpd/ft2
SLR 29 lb/d/ft2 19 lb/d/ft2
Limiting SLR 39 lb/d/ft2 30 lb/d/ft2
Maximum lb of solids that
can be loaded in the
secondary clarifiers
Percentage of SLR to
Limiting SLR 74% 65% Less than 70% of limiting SLR

3.2.2.2 Design
The aeration basins are configured and sized to provide organic removal, nitrification, and denitrification.

During the alternatives analysis carried out in the Project Definition Report (Jacobs 2025), the City selected the MLE configuration to meet Effluent Criteria 1. The MLE configuration consists of a pre-anoxic zone and aerobic zone. In the MLE process, a mixed liquor return (MLR) is included to feed nitrate to the anoxic zone directly from the aerobic zone, in addition to the nitrate from the recirculating RAS. The MLR ratio will range from 2 to 4 times the influent flow. Mixers will be installed in the anoxic zone to keep the solids in suspension.

An alternatives evaluation was carried out to determine whether to modify existing basins to the MLE configuration or to construct two new basins (Section 2). The City has selected to go with constructing two new aeration basins––Aeration Basin 4 and Aeration Basin 5––and abandoning the existing basins. The existing basins will be decommissioned until they need to be demolished for future expansion of the aeration basins and construction of additional secondary clarifiers. The sizing of the aeration basins is based on the 2050 MMWW conditions (described in Table 1-3). The theoretical minimum aerobic solids retention time (SRT) required at a water temperature of 13°C was estimated to be 4 days (C.P. Leslie Grady Jr. et al. 2011). A nitrification safety factor of 2.5 was applied to this theoretical minimum aerobic SRT to get the design aerobic SRT of 10 days. Only one aeration basin will need to be online in the dry weather season, allowing other aeration basins to be maintained. During WW conditions, both aeration basins will need to be operational. The process design criteria for the aeration basins and aeration basin sizing are presented in Table 3-6. and Table 3-7, respectively.

Table 3-8 presents the equipment to be installed in the aeration basins. One baffle will be installed in this Project to create the anoxic/aerobic zones for the MLE configuration. If in the future more stringent effluent nitrogen or phosphorus limits are included in the NPDES permit, additional baffle walls can be constructed in these new aeration basins to convert them to a four-stage Bardenpho. Additional reactor volume may be required in this scenario, which will be determined in the future. Each aeration basin includes a submersible pump to pump MLR from the end of the aerobic zone to the start of the anoxic zone. One shelf spare will be included for the MLR pump in this Project. One hyperboloid mixer will be installed in each anoxic zone.

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Table 3-6. Process Design Criteria for Aeration Basins
Parameter Value Units
Configuration type MLE (Plug Flow) -
Zones 1-Anoxic/1-Aerobic -
Design Year 2050 MMWW -
Treatment Volume Required 1.20 MG
Anoxic Zone Fractions 15 % of total volume
Mixed Liquor Recycle Flow from Aerobic
Zone to Anoxic Zone
200–400 % of bioreactor influent flow with a
maximum flow of 12 mgd
Minimum sustained temperature,
(assumed) 13 °C
DO Setpoint 2 mg/L
Aerobic SRT/total SRT 10/12 days
MLSS range at 2050 MMWW loading 3,500 mg/L
DO = dissolved oxygen
mg/L = milligram(s) per liter
Table 3-7. Aeration Basin Sizing
Parameter Value Units
Number of Aeration Basins 2 -
Volume per Aeration Basin 600,000 gal
Volume of Anoxic Zone per Aeration Basin 90,000 gal
Volume of Aerobic Zone per Aeration Basin 510,000 gal
Width of Aeration Basin, each 22.25 ft
Length of Anoxic Zone, each 24.58 ft
Length of Aerobic Zone, each 139.33 ft
Depth (Side Water) 22 ft
Freeboard 3 ft
gal = gallon(s)
Table 3-8. Aeration Basin Associated Equipment
Parameter Value Units
Baffle Wall 1 -
Anoxic Zone Mixers, per Aeration Basin 1 -
Mixer Type Hyperboloid -
Anoxic Zone Mixer Motor Size 1.5 hp
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Parameter Value Units
Drive Type Constant Speed -
Mixed Liquor Recycle Pump, per Aeration Basin 1 -
Mixed Liquor Recycle Pump Type Submersible
Mixed Liquor Recycle Pump Capacity, each 4/6 mgd
Mixed Liquor Recycle Pump TDH, each 10/16 feet
Mixed Liquor Recycle Pump Motor Size, each 35 hp
Drive Type Adjustable Speed -
DO Probe, per Aeration Basin 2
The performance of existing Secondary Clarifier 4 and Secondary Clarifier 5 were evaluated using the SUMO process model along with Jacobs PClarifier tool. PClarifier uses solid flux theory and SPA to determine the limiting conditions on the clarifier (solids or hydraulic loading). The SPA showed that the two existing secondary clarifiers will have sufficient capacity for the MLE process until 2047, when the MMWW influent flow is 2.9 mgd, and BOD5 loading is 6,300 lb/day (Jacobs 2025). The City will need to start planning and designing Secondary Clarifier 6 in 2043 (for MLE process), when the MMWW influent flows reach 2.8 mgd and BOD5 loading of 5,900 lb/day (Jacobs 2025). If more stringent limits are included in the NPDES permit earlier, then Secondary Clarifier 6 will be needed with the four-stage Bardenpho process.

3.2.3 Aeration System
Air required to oxidize the organic constituents will be supplied by positive displacement blowers and distributed within the aerobic zone by submerged diffusers.

The diffusers will be membrane type with a higher density of diffusers at the start of the aerobic zone tapering down to a low density of diffusers at the end of the aerobic zone. Low-pressure air from the new blowers will be distributed to each aeration basin. Airflow at each aeration basin will be split into three diffuser grids. This split is done to make it easier to modify the diffuser grid if the aeration basins need to be converted to a four-stage Bardenpho. All air flow splits will be actively controlled using motorized butterfly flow control valves and thermal mass flow measurement. Table 3-9 summarizes the air demand for different scenarios, and Table 3-10 summarizes the aeration system equipment.

Table 3-9. Air Demands
Design Condition Value Units
Peak Flow Air Demand a 1,738 scfm
2050 Max Month Wet Weather Air Demand 1,424 scfm
2050 Max Month Dry Weather Air Demand 961 scfm
Minimum Air Demand 293 scfm
a Based on the maximum influent flow of 4 mgd and 2050 MMWW loadings scfm = standard cubic foot(feet) per minute
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Table 3-10. Aeration System Equipment
Parameter Value Units
Type Submerged Diffuser. Membrane Disk Type -
Material Membrane Type -
Number of Diffusers in each Aeration Basin 348 -
The existing blowers are single-speed, multi-stage centrifugal blowers housed in the blower building.

Because Aeration Basin 4 and Aeration Basin 5 are deeper than the existing aeration basins, the existing blowers cannot supply air at the required pressure. Therefore, new blowers are needed in this Project.

The new blowers will be housed outdoors under a canopy close to the new aeration basins. Three positive displacement rotary screw-type blowers (2 duty + 1 standby) will be provided. Each blower will include suction filters, control panel, a variable-frequency drive (VFD), temperature and pressure sensors, silencers, and a check valve. Isolation valves will be provided on the suction and discharge side of each blower. The compressed air will flow out of the blower and into the header, from where it will flow into the aeration basins. Table 3-11 summarizes the design criteria for the blowers.

Table 3-11. Blower Equipment Design Criteria
Parameter Value Units
Blower type Positive Displacement (Screw-type) -
Number of aeration blowers 3 (2 Duty/1 Standby) -
Maximum Capacity per Blower 1,115 scfm
Turndown 70 %
Discharge pressure required 11 psi
Blower power 50 hp
Drive Type Adjustable Speed -
psi = pound(s) per square inch

3.2.4 RAS/WAS Pumping
The RAS/WAS pump station is a complete replacement of the existing system in order to increase the capacity of the RAS pump station. The existing pump station can only provide up to a total of 2.3 mgd.

RAS pumping is designed to be flow paced based on the influent flow at a rate of 50 to 100% of the maximum month flow. Each secondary clarifier will have a dedicated RAS pump and a swing RAS pump that can serve either secondary clarifier. The RAS will be pumped to the PE/RAS mixing box. Two WAS pumps are in a duty/standby configuration at the station. The WAS pumps are also connected to the suction header of the RAS pumps. When sludge needs to be wasted, the WAS pumps will be continuously discharging to the existing WAS storage basin.

The design criteria for the RAS and WAS pumps is provided in Table 3-12, Table 3-13 and Table 3-14 summarize the pump sizing for the RAS and WAS pumps, respectively.

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Table 3-12. Design Criteria for RAS/WAS Pumps
Parameter Value Units
RAS rate 0.73 to 3.13 mgd
WAS Flows (min to max) 29,100 to 43,800 gpd
WAS Concentration (min to max) 4,000 to 7,100 mg/L
WAS Loads (min to max) 1,027 to 2,550 lb/d
Table 3-13. RAS Pump Sizing
Parameter Value Units
Number of pumps 3 (2 Duty, 1 Standby) -
Pump type Horizontal End Centrifugal Screw Pump -
Pump Capacity Min 609, Max 1,089, Average 763 gpm
TDH 36 ft
Motor size 20 hp
Table 3-14. WAS Pump Sizing
Parameter Value Units
Number of pumps 2 (1 Duty, 1 Standby) -
Pump type Hose Pump -
Pump Capacity 20–30 gpm
TDH 10 ft
Motor size 5 hp

3.2.5 Chemical Feed and Storage
Supplemental alkalinity will be dosed in the aeration basins to offset alkalinity consumed because of nitrification. Magnesium hydroxide slurry will be used for alkalinity addition. The slurry will be dosed into the RAS pipe (entering the new PE/RAS mixing box) by means of an injection quill. The chemical dosing system for magnesium hydroxide will be situated outdoors and will consist of a storage tank, one peristaltic chemical metering pumps skids (1 duty, 1 standby), and the facility curb providing drip containment. The dosing pumps will be housed under a canopy.

Magnesium hydroxide slurry required (as CaCO3) was calculated for the startup and design year for various flow conditions, factoring in the incoming alkalinity in the plant influent (as CaCO3). The flow condition requiring the most alkalinity addition (2050 average WW) was chosen as the basis of design for the chemical dosing system. Approximately 1,800 gallons of storage volume is required for 28 days for the 2050 average WW conditions. The magnesium hydroxide storage tank (9 ft diameter, 10 ft straight sidewall height) is designed for a working volume of ~4,750 gallons. This capacity provides up to 74 days of storage at average WW influent flowrate. Chemical dosing will be flow paced and will vary based on influent flow.

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Magnesium hydroxide slurry is nonhazardous and noncorrosive, making it safe to handle. It is still classified as an irritant, and safety glasses and gloves are recommended for handling. The slurry can freeze in cold weather (less than or equal to 5°C). Hence, the storage tank will be equipped with a topentry vertical mixer to keep the slurry in suspension, and the dosing pumps suction and discharge lines will be heat-traced to prevent clogging in pipelines.

The design basis for the magnesium hydroxide system is shown in Table 3-15. Magnesium hydroxide storage and equipment sizes are presented in Table 3-16.

Table 3-15. Design Criteria for Magnesium Hydroxide System Parameter Value Units
Dosing control strategy Flow paced (Influent Flow) -
Magnesium hydroxide strength 60 %
Magnesium hydroxide product density 12.5 lb/gallon
Minimum dosing rate
(at 2028 avg. DW conditions) 0.5 gph
Maximum dosing rate
(at 2050 avg. WW conditions) 2.6 gph
Dosing location PE/RAS Mixing Box -
Storage location Outdoors -
28-day storage volume needed for 2050 avg. WW
conditions ~1,800 gal
Days of storage (at 2050 average WW conditions) 74 days DW = dry weather
gph = gallon(s) per hour
Table 3-16. Chemical Metering Pump and Storage Sizing
Parameter Value Units
Number of pumps 1/1 Duty/Standby
Pump type Peristaltic metering -
Number of storage tanks 1 (flat-bottom vertical tank) - Size per storage tank 4,750 gal
Sodium hypochlorite chemical (12.5%) will be required for foaming control in the aeration basins on an as-needed basis. The chemical aids in settling by destroying the filaments responsible for foaming. Since sodium hypo can has a short shelf life (3-6 months) and is required rarely, a permanent storage setup has not been provided. Space has been allocated outside the chemical facility, on the south side next to the aeration basins, to temporarily install a 55-gallon sodium hypo drum, a chemical metering pump, and a 66-gallon spill containment pallet, whenever the chemical is required for foaming control. A permanent piping connection to connect the sodium hypo metering pump to the aeration basins has been provided.

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3.2.6 WAS and Filtrate Storage Upgrades
The WWTP has three existing tanks: one for WAS storage and the other two for storing and equalizing the filtrate produced by the thickening and dewatering processes. Figure 3-1 shows the layout of these tanks.

Typically, the WWTP only uses one tank for filtrate storage. These tanks are adjacent to the existing aeration basins. The tanks include coarse bubble diffusers for mixing with air supplied from the existing blowers. Because the existing aeration basins and blowers will be decommissioned after this Project, a new blower is needed to supply air to these tanks. The new blower will be a positive displacement type because of the varying liquid levels in the tanks. Actuated valves will be located on the air headers going to each tank to regulate the airflow. The new blower will be housed in the building adjacent to the mixed liquor effluent channel. The coarse bubble diffusers will also be replaced as part of this Project.

Figure 3-1. Layout of the WAS Storage Tank and Filtrate Storage Tank The existing gravity belt thickener feed pumps will continue to draw WAS from the WAS storage tank and send it to the gravity belt thickener. The stored filtrate will be pumped to the primary clarifier influent splitter box.

The WAS storage tank, filtrate tanks, and blower design criteria and process sizing are provided in Table 3-17, Table 3-18, and Table 3-19 respectively.

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Table 3-17. WAS Storage Equipment Sizing
Parameter Value Units
Number of storage tanks 1
WAS tanks operation Coarse Bubble Mixer
WAS storage tank volume 22,000 gal
Average sidewater depth 10 ft
WAS storage capacity < 1 day days
Air demand for mixing 50 scfm
< = less than
Table 3-18. Filtrate Storage Equipment Sizing
Parameter Value Units
Number of storage tanks 2 -
WAS tanks operation Coarse Bubble Mixer -
Filtrate storage tank volume – 95,000
– 73,000
gal
Average sidewater depth 10 ft
Air demand for mixing – 250
– 200
scfm
Table 3-19. WAS and Filtrate Storage Tanks Blower Equipment Design Criteria Parameter Value Units
Blower type Positive Displacement -
Number of blowers 1 -
Capacity per blower 500 scfm
Discharge pressure 5.5 psi
Blower power 20 hp
Drive type Adjustable Speed -
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4. Discipline Design Criteria
This chapter of the BODR provides specific design criteria parameters and details as they relate to the technical disciplines involved in the Project. The stated design criteria have been selected based on the previously stated Project goals and objectives.

4.1 Site Civil

4.1.1 General Description
This section defines and documents the site development. The recommended layout will lead to further development in subsequent design phases. Items addressed in this section include the basis for layout, such as major site features, paving, and site grading, as shown on the drawings.

4.1.2 Codes, Regulations, and Standards
The following codes, standards, and specifications will apply to the site civil and yard piping design. Unless otherwise specifically stated, the latest edition of the codes will apply. ▪ 2024 California Department of Transportation Standard Plans and Specifications ▪ ASTM International (ASTM) Standards
▪ California Building Code (CBC) and Fortuna Municipal Code ▪ California Division of Occupational Safety and Health Construction Safety Orders ▪ California Fire Code
▪ California Plumbing Code
▪ 2018 City of Fortuna – Engineering Division Standard Details ▪ Humboldt Low Impact Development Stormwater Manual
▪ City of Fortuna Stormwater Management Program
▪ California Stormwater Quality Association

4.1.3 Survey
A topographic survey of the site was conducted by Gutierrez Land Surveying in August 2019. In 2021, Jacobs performed a limited survey, documenting the bottom and top elevations of the ponds; outlines of Secondary Clarifiers 1, 2, and 3; filtration tanks; the channel between aeration basin tanks; and the chlorine contact tanks. An additional survey will be carried out to capture existing facilities and site features within the anticipated work areas at the Fortuna WWTP. Existing site features to be verified and calibrated with as-built drawing elevations are as follows:
▪ Pavement on the northern side of Pond 1
▪ Area between the vehicle storage building and the plant building ▪ Space between the primary clarifiers and the grit removal chamber ▪ Surroundings of the secondary clarifiers and aeration basin tanks Structure and piping elevations will also be documented for these features:
▪ Aeration basin tanks
▪ Blower
▪ Influent pump station
▪ Meter vault
▪ Primary Clarifier 2
▪ RAS pump station
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▪ RAS/WAS split station
▪ Valve
The collected data will be combined with previous surveys and record drawings to create a site base map of existing features. Horizontal datum used is the North American Datum of 1983, and vertical datum is the North American Vertical Datum of 1988 (NAVD88); all coordinates and elevations are reported in feet.

Some earlier projects used elevations based on the National Geodetic Vertical Datum of 1929. To align with NAVD88, those elevations will be adjusted by adding 3.321 ft. This conversion factor was determined for the WWTP site using National Oceanic and Atmospheric Administration’s National Geodetic Survey Coordinate Conversion and Transformation Tool.

4.1.4 Demolition
The contractor will transport demolished materials offsite to approved disposal facilities in accordance with applicable local regulations. If any hazardous materials—such as asbestos, lead-based paint, or contaminated soil—are encountered during construction, the contractor must notify the engineer before handling or developing mitigation measures. All mitigation plans must be reviewed by the engineer and coordinated with the Humboldt Waste Management Authority.

Mixed construction and demolition (C&D) waste will be taken to facilities approved by the California Department of Resources Recycling and Recovery or recognized by Humboldt Waste Management Authority.

The City requires compliance with its C&D Debris Diversion ordinance, as detailed in Chapter 15.48 of the Fortuna Municipal Code. This ordinance requires that at least 65% of C&D waste from applicable projects be diverted from landfills through reuse or recycling, unless an exemption is granted because of infeasibility. The contractor must submit a Construction Waste Management Plan for approval and maintain documentation of all waste diversion activities

4.1.5 Grading and Drainage Design Criteria
Overall, the site will be graded to direct stormwater runoff away from buildings and toward designated stormwater management features. Final grading will incorporate rounded and varied fill and cut slopes to avoid abrupt elevation changes, integrate with the natural terrain, and enhance the site’s visual appeal.

The grading design will aim to prevent onsite ponding. Grading and erosion control will comply with City policies and Humboldt County regulations. Low-impact development practices will be used to manage stormwater in an environmentally sustainable manner. Efforts will be made to preserve existing grade elevations as much as possible throughout the grading process.

The Fortuna WWTP in Humboldt County, California, lies within a Federal Emergency Management Agencydesignated 100-year floodplain (Zone AE), indicating a 1% annual chance of flooding and requiring compliance with specific building standards.

4.1.6 Site Layout
The proposed site plan includes several new features, including aeration basins, a PE/RAS mixing box, a chemical storage and pumping facility, an FEB pump station, and yard process piping. These new facilities will be situated north of the existing aeration basins. The FEB pump station will be on the northern side of Equalization Pond 1. Upgrades are also planned for the existing RAS pump station, blower structure, and the RAS/WAS split station, which are south of the existing clarifiers. The existing liner in Equalization Pond 1 will be removed and replaced. The selection of the new liner material will be based on criteria such as constructability, permeability, cost, durability, vehicle access, and long-term performance.

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4.2 Yard Piping
The pipe schedule, Drawing 000-G-0022, identifies the sizes, flow stream, pipe materials, and testing requirements. Major yard piping consists of the following:
▪ Plant influent bypass
▪ Plant influent return
▪ PE
▪ RAS
▪ WAS
▪ Utility water
The following tie-ins to existing utilities will be required:
▪ PE
▪ Utility water
▪ RAS
The following requirements will be applied to piping design and construction:
▪ Piping will be located so that it is not a safety hazard nor a barrier to equipment access. ▪ The minimum depth of cover for buried pipelines will be 30 inches. If this minimum coverage cannot be provided, the pipe will be concrete encased.
▪ The minimum percentage slope on gravity lines will be 1 degree. ▪ Manual vent valves will be provided on the highest point and every local high point of every pipeline to be filled with liquid or to be tested hydrostatically.
▪ Exposed piping will be identified with fluid service and flow direction.

All facilities will be required to be operational during construction. Temporary piping will be needed for the following facilities:
▪ Plant influent overflow/FEB
▪ RAS/WAS piping

4.3 Architecture
The new blower and chemical storage facility includes an open metal canopy roof structure.

4.3.1 Codes, Regulations, and Standards
All new facilities and existing facilities to be rehabilitated will be designed to conform to the following codes, standards, and regulations, as adopted by the City of Fortuna Municipal Code. The 2025 editions of California Codes went into effect on January 1, 2026, and will be used for this Project. ▪ 2025 California Administrative Code (Part 1 of Title 24) ▪ 2025 CBC (Part 2 of Title 24)
▪ 2025 California Electrical Code (Part 3 of Title 24)
▪ 2025 California Mechanical Code (Part 4 of Title 24)
▪ 2025 California Plumbing Code (Part 5 of Title 24)
▪ 2025 California Energy Code (Part 6 of Title 24)
▪ 2025 California Fire Code (Part 8 of Title 24)
▪ 2025 California Existing Building Code (Part 10 of Title 24) ▪ 2025 California Green Building Standards Code (Part 11 of Title 24) Funding Application Technical Report Update
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4.3.2 Energy Code Data
Fortuna, California, is defined as Climate Zone 1 according to California Building Climate Zones and California Energy Code – 140.3 Requirements for Building Envelopes. Note that the current proposed designs are for open-air canopies with no proposed conditioning or insulation. ▪ Roof or Ceiling Insulation – Maximum U-Factor of U-0.034 (R-29.4) ▪ Wall Insulation – Maximum U-Factor of U-0.095 (R-10.5) ▪ Exterior Doors – Maximum U-Factor of U-0.7 (R-1.5)
▪ Exterior Fenestration
- Maximum U-Factor of U-0.36
- Maximum Relative Solar Heat Gain Coefficient – 0.25
- Maximum Window-Wall Ratio – 40%

4.3.3 Accessibility and Universal Design
Accessibility is defined by the CBC, Chapter 11B: Accessibility to Public Building, Public Accommodations, Commercial Buildings, and Public Housing.

In accordance with 11B-203.5 Machinery Spaces: Spaces frequented only by service personnel for maintenance, repair, or occasional monitoring of equipment will not be required to comply with these requirements or to be an accessible route. Machinery spaces include mechanical, electrical, or communications equipment rooms, water, or sewage treatment pump rooms and stations, for example.

4.3.4 Design Concepts
Currently, no new enclosed facilities are proposed. Any scope changes to include new facilities will use and reference the construction of the existing concrete masonry unit facilities onsite to match visual aesthetics and functional performance and specified to comply with current California building and energy codes.

An open canopy structure is proposed for the outdoor blowers and chemical storage. This canopy will be primarily structural in nature. The roofing material will be chosen to be consistent with the existing green standing seam metal roofing onsite (refer to Figure 4-1 for a reference photo of the existing roofing at the digester building). The new canopy will be designed as an open structure only with no future consideration for enclosure (that is, no future tie-in at the wall or roof transitions, and no insulation).

Figure 4-1. Existing Standing Seam Metal Roof (Digester Building) Funding Application Technical Report Update
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Signage:
▪ Safety, informational, and hazardous material signs will be provided as required by code and safety standards.

Interior Systems:
▪ Any proposed modifications to existing interior spaces will consider interior surfaces and finishes for appropriateness to the individual spaces. Consideration will be given to the need for washdown, corrosion resistance, slip resistance, light reflectance, comfort, and maintenance.

4.3.5 Code Summary
▪ Proposed Chemical Storage and Blower Facility (#350)
- Industrial Occupancy (Group “F-1”)
- Type II-B Construction (Noncombustible)
- 25 ft by 20 ft Footprint (500 ft2) – 15,500 ft2 Allowable - Max Height – 55 ft
- Exit Access Travel Distance – Max 200 ft

4.3.6 Chemical Material Storage
The proposed chemical storage is an outdoor storage facility adjacent to a structural canopy for weather protection of the associated equipment. Approximately 5,000 gallons of magnesium hydroxide slurry will be stored in the outdoor containment area. The magnesium hydroxide slurry does not meet any criteria for hazardous material as defined by California Building and Fire Codes(refer to Table 4-1). Although it does not meet the criteria for an outdoor control area of hazardous materials, the chemical storage area will consider the code requirements for hazardous control to the extents feasible.

Table 4-1. Hazardous Material Requirements (Outdoor Storage Control Area) Type
Hazard – #,#,#,# (Per NFPA 704)
(Health, Flammability, Instability,
Special) Storage Amount
Magnesium Hydroxide Slurry (60%) HAZARD - 0, 0, 0, 0 5,000 gallons in total Outdoor Control Areas
The outdoor control areas will be kept free from weeds, debris, and common combustible materials not necessary to the storage. The area surrounding an outdoor control area will be kept clear of such materials for not less than 15 ft. (T24-9-5003.12)
NFPA = National Fire Protection Association

4.4 Geotechnical
The geotechnical design criteria were estimated based on data collected from three cone penetrometer test soundings performed by SHN Consulting Engineers and Geologists for the current improvements. The 2025 geotechnical data report is included in Appendix C of this BODR. Data from soil borings and laboratory testing performed for previous improvements to the WWTP were also evaluated.

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4.4.1 Soil Profile
The generalized soil profile consists of clay and silty clay soil from the ground surface down to a depth of 28 to 33 ft. The clay generally has an estimated undrained shear strength of 800 to 1,000 pounds per square foot (psf) based on the cone resistance. Sand lenses or gravel are present in some areas within the upper clay soil. The clay soil is underlain by dense sand and dense silty sand soil to a depth of at least 50 feet below the ground surface.

4.4.2 Seismic Site Class
The soil site classification for seismic design was estimated using the average shear wave velocity that was measured in the cone penetrometer test (CPT) sounding CPT-25-3. Test sounding CPT-25-3 met refusal at a depth of 38 ft beneath the existing ground surface, and the shear wave velocity at greater depth was assumed to be equal to 1,400 ft per second within the hard formation down to a depth of 100 ft. This appears to be conservative because the cone resistance was greater than the CPT-25-3 in the sand between 38 ft to 50 ft below ground surface in CPT-25-01. The average shear wave velocity for the upper 100 ft was 1,005 ft per second, calculated in accordance with American Society of Civil Engineers (ASCE) 7-22. The average shear wave velocity corresponds to Site Class CD.

4.4.3 Groundwater
Groundwater was encountered between 6 to 8 ft below ground surface during explorations based on pore pressure dissipation tests within the CPT soundings. Dewatering will be required during construction of the proposed aeration basins and pump station. The dewatering wells should be screened at least from 10 to 30 ft below ground surface to capture water in the silt and sand lenses within the clay in addition to the underlying dense sand. Artesian conditions were not observed from the pore pressure dissipation test data.

4.4.4 Bearing Capacity
The proposed aeration basins will be embedded at least 20 ft below ground surface. Excavated soil will weigh more than the structure filled with water, and post-construction settlement is anticipated to be negligible. The aeration basin foundation can be designed using an allowable gross bearing pressure of 3,500 psf for static vertical loading. The bearing pressure is limited due to potential settlement. The allowable gross bearing pressure for temporary load conditions, such as seismic loads, is 5,000 pounds per square foot.

Shallow foundations for miscellaneous structures underlain by native soil may be designed using an allowable gross bearing pressure of 1,250 psf for dead plus live loads. For seismic loading, an allowable gross bearing pressure of 2,000 psf can be used. For shallow foundations underlain by more than 8 feet of structural fill material, the allowable gross bearing pressure is 3,000 psf for dead plus live loads. For seismic loading, an allowable gross bearing pressure of 4,000 psf can be used.

For design of flexible concrete slabs, a coefficient of subgrade reaction of 75 pounds per cubic inch can be used for a 1 ft by 1 ft square load (ks1). For a mat foundation acted upon by loads spaced B feet, the applicable coefficient of subgrade reaction, ks, should be determined by the following equation:
𝑘𝑠 = 𝑘𝑠1 (
𝐵 +1
2𝐵
)
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4.4.5 Lateral Earth Pressures
The native clay soil should not be used as backfill around buried structures, as the lateral pressure could be excessive because of expansive clay pressure as the soil becomes wet. Imported structural fill materials should be used as backfill around buried structures. The structural fill should be mostly sand and gravel, and have between 5 to 20% material passing the No. 200 sieve. The plasticity index of the fines should be no greater than 12.

The lateral earth pressures for buried structures should be calculated using the pressure from an equivalent fluid with the recommended density listed in Table 4-2 for active, at-rest, and passive wall loading.

Table 4-2. Lateral Earth Pressure Criteria for Buried Structures Case
Earth Pressure
Coefficient for
Native Soil
Equivalent Fluid
Density for Saturated
Native Soila
(pcf)
Earth Pressure
Coefficient for
Structural Fill
Equivalent Fluid
Density for Saturated
Structural Filla
(pcf)
Active 0.32 84 0.27 81
At-rest 0.52 96 0.46 94
Passive 3.0 265 3.5 335
a Undrained, or saturated, equivalent density values include the pressure of water in addition to the soil. pcf = pound(s) per cubic foot
The recommended lateral pressures for native soil assume an effective internal friction angle of 29 degrees and a saturated unit weight of 127 pcf. The recommended lateral pressures for structural fill assume an effective internal friction angle of 33 degrees and a saturated unit weight of 130 pcf. The soil should be assumed to be saturated up to the ground surface. Active conditions assume that the wall is free to rotate. At-rest conditions apply to restrained structural walls. Lateral load passive resistance applies to soil resisting horizontal loads. The passive resistance requires significant movement to develop the full resistance, and the passive values listed in Table 4-2 are reduced from their maximum values at large strainlimit displacement. A sliding coefficient of 0.35 times the normal load on the foundation is recommended for frictional resistance of the structure foundations sliding against the native soil.

Dynamic soil forces from the 2,475-year design earthquake event were estimated in accordance with Mononobe-Okabe methods. For lateral earth pressures during an earthquake, a dynamic lateral nominal force equal to 21H2should be added to the static lateral active earth force for walls that are backfilled with structural fill, where H equals the height of the wall, in feet, from the base of footing to the top of the retained soil; and the force is in pounds. The dynamic lateral force should be applied at a height of one-third of the wall height above the base of the wall footing. Additional dynamic forces from water within the soil is unnecessary in accordance with the conservatism included in the Mononobe-Okabe theory and case history performance of retaining walls during earthquakes.

For buried structures, the dynamic soil forces from the design earthquake event can alternatively be represented as an additional uniform pressure of 17H, where H equals the height of the wall in feet, from the base of footing to the top of the retained soil, and the pressure is in pounds per square foot. The lower dynamic force from either the Mononobe-Okabe or alternative force from uniform pressure methods can be used for seismic design load cases.

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4.4.6 Construction Considerations
Dewatering should be completed prior to the start of excavation to reduce subgrade moisture content and improve subgrade stiffness. There is a risk of settlement of structures surrounding the excavation caused by dewatering if there are organic soils or peat layers beneath the structures. A trace of peat in silt was noted in a soil boring near the proposed aeration basins, around 25 feet below the existing ground surface. Settlement monitoring of existing structures should be performed during dewatering operations.

The proposed aeration basins are underlain by approximately 10 feet of compressible silty clay with some organics. This soil is anticipated to be very soft even after dewatering, and will be difficult to dry out in the coastal climate. Even if the near-surface subgrade soil is dried to near the optimum moisture content, the underlying soft silt and organics will likely cause the prepared subgrade to yield and pump under the compaction effort. Also, the estimated settlement of the aeration basin structure is greater than 2 inches with a potential differential settlement of approximately ¾ inches. The upper 2.5 feet of native soil beneath the aeration basin should be overexcavated and replaced with foundation stabilization rock wrapped in woven geotextile. The thick mat of rock will function to stabilize the soft subgrade and also reduce the differential settlement to less than 0.25 inches. The estimated total settlement of the basins after construction is approximately 1.75 inches.

The proposed shallow structures should be underlain by 6 inches of aggregate base rock to provide a stable working surface for construction. The subgrade beneath the aggregate base rock should be proof rolled with heavy construction equipment to check for soft, pumping or yielding areas prior to placement of the aggregate base rock.

4.5 Structural

4.5.1 Structural Criteria
The structural criteria have been developed to provide a common basis for all structural designs in line with accepted structural practice and standards for improvements to the Fortuna WWTP structures.

4.5.1.1 Applicable Codes and Standards
The following summarizes the specific codes and industry standards that will be used as basis of design so that the strength and quality of the materials and design procedures meet the required standards. ▪ 2025 CBC
▪ 2025 California Existing Building Code
▪ American Society of Civil Engineers, Minimum Design Loads and Associated Criteria for Buildings and Other Structures 2022 (ASCE 7-22)
▪ American Concrete Institute (ACI), Specifications for Concrete Construction (ACI 301-20) ▪ American Concrete Institute, Building Code Requirements for Structural Concrete 2019 (ACI 318-19) ▪ American Concrete Institute, Code Requirements for Environmental Engineering Concrete Structures (ACI 350-20)
▪ American Concrete Institute, Code Requirements for Seismic Analysis and Design of Liquid-Containing Concrete Structures (ACI 350.3-20)
▪ American Institute of Steel Construction, Specifications for Structural Steel Buildings 2022 (AISC 360-22)
▪ Aluminum Association, Aluminum Design Manual 2020
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▪ American Welding Society, Structural Welding Code – Steel 2020 (AWS D1.1) ▪ American Welding Society, Structural Welding Code – Aluminum 2020 (AWS D1.2)

4.5.1.2 Existing Structural Documents
▪ Water Pollution Control Facilities, City of Fortuna, As-Built Structural Drawings, Winzler & Kelly Consulting Engineers, March 1974.

4.5.2 Loads

4.5.2.1 Dead Loads
Dead loads consist of structural self-weight of all new structures as well as the weight of any additional equipment being added to the facilities. In addition, 5-pound-per-square-foot (psf) load will be added as collateral load.

4.5.2.2 Live Loads
The live loads are shown in Table 4-3.

Table 4-3. Design Criteria for Live Loads at the Aeration Basin Platform Parameter Value Unit(s)
Walkway 60 psf
Stairway and exits 100 psf
Mechanical equipment 200 psf
Roof live load 20 psf
Railing 50 plf or 200 lb concentrated -
lb = pound(s)
plf = pound(s) per linear foot

4.5.2.3 Snow Loads
The design criteria for snow loads are shown in Table 4-4.

Table 4-4. Design Criteria for Snow Loads
Parameter Value Unit(s)
Ground Snow Load 14, per ASCE-7 Hazard tool psf
Winter Wind Parameter, W2 0.35 -
Surface Roughness Category B -
Exposure of Roof Fully exposed -
Exposure Factor, Ce 0.9 -
Thermal Factor, Ct 1.2 -
Slope Factor, Cs Per CBC -
Unbalanced snow loads as required by ASCE-7
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4.5.2.4 Wind Loads
The wind loads are shown in Table 4-5.

Table 4-5. Design Criteria for Wind Loads
Parameter Value Unit(s)
Basic wind speed, V 103, per ASCE-7 Hazard tool mph
Risk Category IV -
Exposure Category C -
Topographic Factor, Kzt 1.0 -
Ground Elevation Factor, Ke 1.0 -
Velocity Pressure Exposure Coefficient, Kz Per CBC -
mph = mile(s) per hour

4.5.2.5 Seismic Loads
The seismic design parameters shown in Table 4-6 are in accordance with ASCE 7-22 and based on the ASCE online Hazard tool.

Table 4-6. Design Criteria for Seismic Load
Parameter Value Unit(s)
Mapped Spectral Response Acceleration
Short Period, SS 3.02 -
1 Second Period, S1 1.15 -
Design Spectral Response Acceleration
Short Period, SDS 2.14 -
1 Second Period, SD1 1.26 -
Site Soil Class CD -
Risk Category IV -
Importance Factor 1.5 -
Seismic Design Category, SDC F -

4.5.2.6 Hydrodynamic Loads
The hydrodynamic forces will be developed in accordance with ACI 350.3-20 as modified by ASCE 7-22.

4.5.2.7 Lateral Earth Pressure and Buoyancy
Lateral earth pressures will be developed in accordance with Section 4.4.5 of this report for walls of any proposed new basin. An additional surcharge of 2 ft of soil weight will be added to this load. For details of lateral earth pressure and soil-bearing capacity, refer to Section 4.4 of this report.

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Buoyancy loads will be considered for all structures on the site that are subjected to uplift. Safety design factors for uplift resistance for normal high ground water elevation and 100-year flood elevation are 1.25 and 1.10, respectively.

4.5.3 Construction Materials
Table 4-7 summarizes the major materials that will be used to construct the proposed aeration basin and related facilities.

Table 4-7. Construction Materials for Proposed Facilities Material Parameter Property
Cast-in-Place Concrete:

Minimum Compressive Strength 5,000 psi at 28 days, Normal weight Cement Type Per Specification
Maximum Water to Cement Ratio 0.40
Reinforcing Steel ASTM A615 Gr. 60
Weldable Reinforcing Steel ASTM A706 Gr. 60
Structural Steel:

W-Shapes, T-Shapes, Channels ASTM A992
M-shapes, S-shapes, Angles, Plates, Bars ASTM A572 Gr. 50 Rectangular HSS ASTM A500 Gr. C (Fy = 50 ksi)
Round HSS ASTM A500 Gr. C (Fy = 46 ksi)
Pipes ASTM A 500 Gr. B (Fy = 35 ksi)
Stainless Steel:

Plates ASTM A240 Type 316
Bars and Shapes ASTM A276 Type 316
Aluminum
Aluminum Structural Shapes ASTM B308 6061-T6
Aluminum Plates ASTM B209 6061-T6
Aluminum Grating and Railing ASTM B221 Alloy 6061-T6
Aluminum Welding Electrodes 4043
Bolts and Rods
High-Strength Steel Bolts ASTM F3125 A325
Common Bolts A307
Nuts ASTM A563
Anchor Rods F15554 Gr. 36, 50 or 105
Stainless Steel Bolts ASTM F593 Type 316
Adhesive Anchors Stainless Steel ASTM F593 Type 316
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FY = yield strength
HSS = hollow structural sections
ksi = kilopound per square inch

4.5.4 Structural Systems

4.5.4.1 Proposed Structural Facilities

4.5.4.1.1 Aeration Basin
New aeration basins are proposed, consisting of two 166-foot by 22.25-foot tanks. Each basin will have approximately 24.5 ft high concrete walls resting on a concrete foundation slab. The new aeration basins will be constructed north of the existing aeration basins. Finite element models of the new basin tank have been developed for analysis and design. Preliminary analysis indicates that the tank walls will be 36 inches thick.

4.5.4.1.2 Flow Equalization Pump Station
The new flow equalization pump station consists of a 19-foot by 17-foot buried concrete facility.

The pump station walls are estimated to be 18 inches thick and will be supported by a 20-inch concrete slab. The pump station roof consists of a 12-inch-thick concrete slab.

4.5.4.1.3 Chemical Facility
A new chemical facility is proposed that will consist of a concrete slab with an integrated perimeter concrete curb. The chemical facility will be to the north of the proposed aeration basin and will measure 25 ft by 17 ft in plan. The chemical facility slab will be structurally integrated with the adjacent blower facility.

4.5.4.1.4 Blowers Facility
A new blowers facility is proposed adjacent to the chemical facility that will consist of a metal building system canopy resting on concrete slab. The blowers facility will measure 40 ft by 17 ft in plan and will be integrated with adjacent chemical facility. The main lateral load-resisting systems for the blowers facility will be ordinary moment frames. .

4.5.4.1.5 Mixed Liquor Distribution Box
A new mixed liquor box is proposed, featuring a four-chamber configuration with14 ft by 10 ft footprint.

The structure will consist of 14-inch-thick reinforced concrete walls supported by an 18-inch-thick foundation slab. The partially buried structure includes an aluminum ladder for access to top of facility.

4.5.4.2 Special Inspections and Structural Observation
Special inspections will be required in accordance with Chapter 17 or the 2025 CBC. The design professional in responsible charge will prepare a statement of special inspection in accordance with section 1704 of the code. The statement will identify the requirements of special inspection, including the type and extent of work. In addition, Chapter 17 of the 2025 CBC requires a registered design professional to perform structural observations for structures classified as Risk Category IV.

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4.6 Process Mechanical

4.6.1 Codes, Regulations, and Standards
The mechanical design will use applicable industry standards and design guidance for piping, valves, and process equipment. The following is a list of the more significant resources that will be followed for the design and specification standards:
▪ American Water Works Association
▪ American Society of Mechanical Engineers (ASME)
▪ American National Standards Institute (ANSI)
▪ Hydraulic Institute
▪ NFPA

4.6.2 Process Equipment Layout and Access
The following will be implemented to make the Fortuna WWTP functional, operable, and maintainable.

When developing process equipment layouts, the following minimum requirements will apply:

4.6.2.1 Equipment
▪ Necessary clearance for equipment removal, replacement, or maintenance will be provided in the layout on the drawings. A minimum 3 ft clearance will be provided on at least three sides of the equipment footprint. Additional space will be provided as required for specific equipment. ▪ Flexible connections will be employed to permit easy assembly and disassembly of connections to equipment.
▪ Equipment and panels will be mounted on equipment pads or elevated with legs or by mounting to walls to protect them from washdown.
▪ Ladders and hatches will be provided to access and remove equipment. ▪ Lifting eyes will be provided above equipment not otherwise provided with lifting means (for example, a hoist or crane).
▪ Washdown and utility stations will be provided as needed at each facility to facilitate cleanup and pipe flushing and will have 50 ft of hose provided.

4.6.2.2 Piping and Valves
▪ Piping will be located such that it is not a tripping hazard, a head-knocker, or a barrier to equipment access.
▪ Minimal piping will be located above blowers, compressors, or pumps to facilitate lifting the equipment.
▪ In general, piping will be configured such that it is close to walls where it can be easily supported, particularly in spaces with high ceilings.
▪ Pipe supports and seismic bracing are generally not shown on the layout drawings; however, it will be verified that adequate space is available for installing these supports. ▪ Flexible connections will be employed to permit easy assembly and disassembly of piping. ▪ Valves will be kept within operator reach (below 6 ft), or a chain operator will be provided for valves greater than 6.9 ft above the operating floor.

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4.6.2.3 Hydraulic Calculations
AFT Fathom hydraulic software package will be used to calculate hydraulics and determine pipe sizing.

AFT Fathom performs steady-state, incompressible, Newtonian or non-Newtonian fluid behavior and energy analysis. Fathom is used to calculate pressure drop and flow distribution in liquid and low-velocity gas piping and ducting systems.

Replica is a suite of models and object libraries developed in ExtendSim for dynamic simulation and for optimizing process systems. A Replica dynamic simulation model will be used to develop a hydraulic profile for the treatment plant. A dynamic simulation can also react to conditions that change with time, such as flow demands or water quality. The impacts of changes to hydraulics, process, and control strategies can be observed in operating performance, energy consumption, and chemical consumption.

4.6.2.4 Pump Selection and Hydraulic Calculations
Hydraulic calculations will be prepared for all pump applications. Selected pump operating points will be centered near the pump best-efficiency point at the design condition. A rating point selected to the right of best-efficiency flow will allow higher efficiency at reduced flow and speed. Caution will be exercised in selecting pump operating points at the extremes of the pump operating curve because of possible excessive pump shaft radial loading, reduced bearing life, and possible shaft failure.

Care will be exercised in providing adequate overlap of pump performance when multiple parallel pump installations are provided. Proper pump sequencing requires that pumps have sufficient performance overlap to allow transition adding or dropping pumps in operation.

4.6.2.5 Piping Systems
Process piping includes yard piping, which may be entirely designed and specified outside of the mechanical discipline. Piping for process services and mechanical utilities in the yard also requires civil engineering coordination and consideration for earth loads and traffic loads. ▪ Design Codes and Standards
- ANSI B31.3 – Process Piping
- MSS SP 58 – Pipe Hangers and Supports
- MSS SP 127 – Bracing for Piping Systems: Seismic, Wind, Dynamic Design, Selection, and Application

4.6.2.6 Pipe Materials and Applications
A preliminary Piping Schedule indicating piping services planned for the Fortuna WWTP is provided in the drawings. The schedule is organized by identifying service symbol (legend) and identifies materials, coatings, linings, and test pressures to be used for these services. Updates will be made as design progresses to become the Piping Schedule included in the construction documents.

4.6.2.7 Pipe Supports
The general minimum requirements set out in the contract requirements apply to the pipe supports, anchorage, and seismic bracing of process piping.

The WWTP is in a seismically active region with Seismic Design Category F. The following design and analysis procedures will be conducted:

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▪ Normal fluid service and Category D fluid service, as identified in ASME B31.3, pipes greater than or equal to 6 inches diameter, will require formal pipe stress and flexibility analysis or by-rule analysis as identified in ASME B31.3 Process Piping.
▪ Category D fluid service, as identified by ASME B31.3, pipes less than 6 inches diameter will require byrule pipe stress and flexibility analysis.

Bentley Autopipe software will be used to perform stress analysis on key process pipelines. This includes the low-pressure air piping systems because of the higher system pressure and thermal expansion.

Autopipe is a software that allows the engineer to analyze and visualize pipe stress with static and load sequencing nonlinear systems and to examine different loading scenarios, including thermal, seismic, wind, and dynamic load cases. The software allows the engineer to check pipe stress displacements and clashes caused by the loading cases mentioned previously. Autopipe complies with industry codes and standards such as ASME B31.3.

4.6.2.8 Seismic Design – Pipe Supports
Sway struts and braces will be provided to restrain piping seismic forces as required by the codes listed in the previous subsections.

4.7 Corrosion

4.7.1 Atmospheric Exposure
Atmospheric exposure includes both outdoor and noncorrosive indoor exposures. The following subsections describe anticipated exposure conditions and design approach recommendations. ▪ Polymer-based materials (that is, plastic, nonmetallic) require an ultraviolet barrier (spray applied coating) or ultraviolet-resistant resin embedded within a resin topcoat. ▪ Iron and steel surfaces will be protected from corrosion in all atmospheric exposure conditions.

Exposed carbon steel, cast iron, and ductile iron in the finished construction, in both indoor and outdoor locations, will be coated with epoxy primers and polyurethane finish coats for durability and gloss retention. Highly corrosive areas with high humidity, corrosive gases, and with frequent washdown will receive two coats of epoxy and a polyurethane finish coat. ▪ Steel decking and pre-engineered metal buildings will be coated with manufacturers’ standard coating options. If manufacturers' standard coating offerings do not meet the intended service conditions, then field finish coats will be specified to provide proper corrosion protection. ▪ High temperature piping or surfaces will be insulated for personnel protection. Where condensation can collect beneath the insulation, coatings suitable for the temperature and under insulation will be provided.
▪ Exposed stainless steel will not be coated unless required for color-coding purposes, or if found in contact with dissimilar metals and isolation cannot be incorporated. Generally, an electrical isolation kit will be specified where dissimilar metals are intact.
▪ Copper materials of construction will not require additional protection unless within a chemical facility or exposed to hydrogen sulfide (H2S).
▪ Fluoropolymer (Kynar)-coated aluminum has been used for architectural components and louvers in outdoor service in similar facilities and will be considered for this Project. Anodized aluminum is already used extensively onsite and has performed well. Therefore, aluminum is appropriate for service in exposed conditions present on this Project and will also be considered.

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▪ Concrete and masonry construction components exposed to the atmosphere will not require supplemental corrosion protection but may be painted or stained for architectural purposes.

4.7.2 Submerged Exposure
Submerged exposure includes immersed metals, concrete, and polymer materials exposed to process flow for extended periods, including inside pipe.
▪ Do not use aluminum in submerged conditions.
▪ Provide protective coatings for all submerged ferrous metals. Ferrous metals will have a minimum of 16 mils dry film thickness of epoxy suitable for immersion service. Submerged coatings will be 100% holiday tested.
▪ Use Type 304 or Type 316 for submerged stainless steel to temperatures not exceeding ambient temperatures unless chlorides exceed 100 or 1,000 parts per million of chlorides, respectively. ▪ Liner materials are not anticipated for submerged concrete surfaces unless the water has a strong negative calcium carbonate precipitation potential or has low pH. The new flow equalization pump station is anticipated to have corrosive conditions and therefore will be lined with a coating.

Submerged dissimilar metal connections will be electrically isolated. If electrical isolation is not possible, the dissimilar metals will be coated to minimize the driving potential between the dissimilar metals.

Cement mortar liner performs well in most conditions at a WWTP unless there are air pockets inside a pipe and H2S can be generated. Raw sewage pipes will be lined with ceramic modified epoxy for pipelines.

4.7.3 Buried Exposure
Buried exposure includes metals, concrete, and polymer materials exposed to the region’s native soils. ▪ Chlorides will affect the performance of stainless steel. A geotechnical investigation was performed to determine whether Type 304 and 316 stainless steel requires additional corrosion protection. The latest soil lab test results indicated that the chloride content on this site was approximately 4 ppm, hence no additional protection for stainless steel is required. ▪ Sulfates will affect concrete performance. A geotechnical investigation was performed to determine whether special considerations for mix design, in accordance with ACI 201.2, are required. The latest soil lab test results indicated that the sulfate content on this site was in the range of 11 to 13 ppm. This level of sulfate has no negative impact on Type II Portland cement. ▪ Previous geotechnical report (SHN Consulting Engineers & Geologists, Inc., 2003) indicated that the soil is corrosive. The current geotechnical report (SHN Consulting Engineers & Geologists, Inc. 2025) indicates the soil is corrosive, based on low as-found resistivities, ranging from 2,342 to 2,390 ohmcentimeters, so cathodic protection will be required for buried ferrous metal piping. ▪ Because cathodic protection is required, isolation flanges will be used to electrically isolate the pipe to protect it from other metallic structures such as rebar, grounding wires, pipe supports, and existing pipes. Pipe penetrations into structures will require electrical isolation from rebar and wire ties. ▪ Bonded joints are required for nonwelded joints for electrical continuity. ▪ Thermite-welded wires for test station wires or bond wires will be protected with a weld cap. ▪ Buried steel pipe will be coated with epoxy, or tape coat with cement mortar over coat. Buried ductile iron will be coated with manufacturers’ standard asphalt coating and V-Bio-enhanced polyethylene encasement (ductile iron).

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▪ Protective coatings and cathodic protection are typically not required for buried Type 316 stainless steel pipe.
▪ Buried dissimilar metal connections will be electrically isolated. Where electrical isolation kits cannot be installed, electrical isolation may be achieved by placing a small spool section of plastic pipe such as polyvinyl chloride (PVC).
▪ Buried copper piping will be tape wrapped with 20 mil thick PVC tape.

4.7.4 Hydrogen Sulfide Exposure
H2S exposure can cause major corrosion on some materials, particularly on concrete surfaces inside enclosed basins in upstream process equipment such as utility holes, influent channels, splitter boxes, and primary clarifiers.

The new flow equalization pump station will receive chemical-resistant coatings on the concrete and metal surfaces inside. If the new flow equalization pump station has a consistent minimum water level, the chemical-resistant coating is only required in the headspace (vapor space) to an elevation of 1 ft below the minimum water level.

4.7.5 Chemical Exposure
Chemical storage and pumping facilities will receive secondary containment coatings to protect the concrete floor. Pump materials, tanks, piping, and other miscellaneous appurtenance will be resistant to the chemicals listed herein.
▪ 60% Magnesium Hydroxide: No coating is required for concrete.

4.7.6 Building Systems and Mechanical Equipment
Construction methods and materials will affect the long-term corrosion resistance of structures and equipment. Factors that should be included in design are summarized as follows:
▪ Shop and field welds to stainless steel will be ground smooth and passivated after fabrication in accordance with ASTM A380.
▪ Welded stainless steel components will be low-carbon grade (Type 304L or 316L). Hangers, supports, and mounting hardware for pipe, conduit, and ductwork should be stainless steel. Exceptions will be allowed for specific chemical storage and feed locations where stainless steel is not chemically compatible.
▪ Prevent metal-to-metal contact between buried ferrous metal piping, and between submerged ferrous metals and reinforcing steel in concrete structures.
▪ Aluminum embedded in or attached directly to concrete should be protected by applying bitumastic or epoxy coatings.

4.7.7 Electrical and Instrumentation and Controls Systems and Materials Electrical and instrument and control components can be susceptible to corrosion in treatment plants, typically in chemical or high humidity areas. The following items are recommended to reduce potential for corrosion of these components:
▪ Use PVC-coated or plastic conduit and boxes in wet or moist areas. Exposed metallic components should be stainless steel or aluminum.

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4.8 Building Services

4.8.1 Codes, Regulations, and Standards
New facilities and existing facilities to be rehabilitated will be designed to conform to the following codes, standards, and regulations, as required by federal, state, and local authorities. ▪ 2022 CBC (California Code of Regulations, Title 24)
▪ 2022 California Mechanical Code
▪ 2022 California Plumbing Code
▪ 2022 California Fire Code
▪ 2022 California Building Energy Efficiency Standards for Residential and Nonresidential Buildings ▪ 2022 California Green Building Standards Code
▪ American Society of Heating, Refrigerating, and Air-Conditioning Engineers - Standard 62.1, Ventilation for Acceptable Indoor Air Quality - Standard 90.1, Energy Standard for Buildings Except Low Rise Residential ▪ ASME
▪ American Society of Plumbing Engineers
▪ Air-Conditioning, Heating, and Refrigeration Institute ▪ Sheet Metal and Air Conditioning Contractors’ Association’s HVAC Duct Construction Standards: Metal and Flexible
▪ 2024 National Electrical Code, NFPA 70
▪ 2020 Standard for Fire Protection in Wastewater Treatment and Collection Facilities, NFPA 820 ▪ Occupational Safety and Health Administration’s General Industry Safety Orders

4.8.2 Facility Design Criteria
▪ Outdoor Design Conditions – Based on 2022 California Energy Commission (CEC-400-2002-010-AP; Appendix JA2; Table 2-3) for Fortuna:
- Summer: 75 degrees Fahrenheit (°F) Dry Blub/61°F Mean Coincident Wet Bulb (0.10% occurrence) - Winter: 35°F Dry Bulb (0.2% occurrence)
Table 4-8 lists additional design condition criteria for indoor spaces.

Table 4-8. Design Conditions for Indoor Spaces
Building Area Occupied
Temperature
Humidity
Control
Summer,
maximum
Winter,
minimum
Operations
Building
Operations
Room (SCADA) Yes 74°F 68°F No
Operations
Building Electrical Room No 85°F 50°F No
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Building Area Occupied
Temperature
Humidity
Control
Summer,
maximum
Winter,
minimum
Operations
Building Staff Restroom No 74°F 68°F No

4.8.3 Building Services Materials
Heating, ventilation, and air-conditioning (HVAC) material for ductwork will be aluminum, where required, to prevent corrosion from water atmospheres. All other ductwork will be G90 galvanized sheet metal.

The materials for plumbing are as follows:
▪ General water piping will be supplied in type K or L copper as required to meet service type needs and the National Sanitary Foundation 61 regulations.
▪ General drainage piping will be supplied with Schedule 40 PVC with drain, waste, and vent fittings.

However, any supplied piping in an HVAC plenum will be supplied with listed and labeled chlorinated PVC to meet 2022 California Plumbing Code plenum requirements.

4.8.4 HVAC System Description
Two independent heat pump systems will be provided: one each for the operations room (SCADA) and the electrical room. The operations room will be served by a 2-ton heat pump. The electrical room will require a 3-ton heat pump. Each unit will be high efficiency and will have an economizer. Final location, mounting and placement, and type will be determined during the next Project phase.

4.8.5 Energy Compliance
The HVAC and plumbing systems will comply with the applicable requirements of the 2022 California Energy Code, including applicable local amendments.

4.9 Fire Protection
No buildings or structures require fire sprinkler systems in accordance with the CBC.

4.10 Instrumentation and Control
This section establishes basic criteria and control philosophy for the instrumentation and control systems to be used in the Project design. The intent is to standardize the new equipment and method of control as much as possible, for O&M consistency.

The detailed design, control, and monitoring of local control stations, motor control centers, and safety interlocks will follow Jacobs’ programming standards.

Instrumentation and control components, and the supporting network will be provided for facility operation and controls. Instruments to be used for plant operation, process control, and monitoring are level, flow, pressure, and analytical devices. Each type of instrument will be specified in the specification section of Instrumentation and Control Components.

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4.10.1 Existing Instrumentation and Controls
The design approach for the facility upgrade will prioritize assessing and verifying existing instrumentation. The scope of work for the system integrator will specify that each instrument will be individually checked for functionality by the system integrator to confirm that it meets operational standards and can be integrated seamlessly into the upgraded system. This comprehensive functionality check will be documented by the system integrator in a detailed functionality report, which will serve as a guide for construction and maintenance teams to resolve any issues before cutover of the system begins.

The existing instrumentation and equipment tagging will be modified to align to the new tagging standard as shown in Appendix C. The new tagging standard will significantly increase the number of available tags, providing a robust framework for future expansion and the integration of additional instrumentation and equipment. This Project will specify that updating the existing field tags is included by the general contractor so that all current instrumentation is accurately retagged with stainless steel tags in accordance with the new tagging standard. For clarity during the retagging transition phase, the existing tags numbers will remain, with only the appropriate area prefix being applied.

4.10.2 New Instrumentation and Controls
The instrumentation will be tagged following the tagging standard in Appendix A. The new tagging standard will significantly increase the number of available tags, providing a robust framework for future expansion and the integration of additional instrumentation and equipment. Instruments will be specified to have stainless steel tags provided by the manufacturers. Programming, integration into the SCADA system and startup is assumed to be performed by the Owner’s Programmer. It is assumed that the SCADA system will be upgraded to a new Ignition system with Allen Bradley PLC’s prior to the construction of this project.
12 Strand fiber optic network will be utilized to connect the new PLC’s in the field back to the SCADA Network rack. The Aeration blower panels will use CAT6 ethernet cables to communicate to the blower scheduler panel. RIO racks will be utilized for the WAS and Filtrate blowers area, and the RAS WAS pumping area to provide control while reducing the footprint and cost.

4.10.2.1 Flow Equalization Basin Pump Station
The FEB pump station pump operation will be automatically adjusted based on the influent flow rate, with the number of active pumps and their speeds modulated to maintain the total target flow rate. The station pumps will be configured in a lead/lag/standby arrangement. The control system will include automatic lead pump rotation to create even wear across all pumps. Each discharge line will be equipped with a pressure switch that detects high-pressure conditions. Additionally, each pump will be monitored for overtemperature and for seal leakage, with alarms generated by the control system. The common discharge header will be fitted with pressure and flow transmitters. Digital and analog signals will be integrated into the control system for trending, alarming, and totalization of flows.

4.10.2.2 Magnesium Hydroxide Storage and Dosing System
The magnesium hydroxide storage tank will be equipped with a top-mounted mixer. This mixer can be locally controlled by a HOA switch and will operate continuously in auto whenever the tank level is above a predefined minimum threshold.

To monitor the tank level, the system will incorporate an ultrasonic level transmitter as the primary measurement device. For redundancy, a high-level switch will also be installed to provide backup level detection. These instruments will feed data to a remote display panel adjacent to the tanker truck fill Funding Application Technical Report Update
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connection. This panel will include a strobe light that activates at the full tank level, providing a clear visual indication to operators when the tank is full.

The dosing pumps will be controlled in a lead/standby configuration. The dosing pumps will be controlled to a flow setpoint.

4.10.2.3 Aeration Basins
Each basin will be equipped with dissolved oxygen measurement, as well as air flow measurement and actuated airflow control valves at each zone. Control for the air valves will be 4-20–milliamp signals.

The control valves will be modulated by the control system to control the airflow to the basin. The airflow control valves will be equipped with position feedback. The pressure setpoint will be modulated using most open valve control. Most open valve control improves blower efficiency by maintaining optimal airflow based on real-time demand. It also reduces energy consumption and wear on equipment by avoiding unnecessary over-aeration. The new instruments at each drop zone will be integrated into the control system. Analytical measurements will be trended, and airflow will be totalized.

The basin mixers can be locally controlled by a HOA switch and will operate continuously in auto.

The MLR recirculation will be measured by a magnetic flow meter. The pump speed will be controlled to a flow setpoint.

The two DO probes on each aeration basin will be wired to a single transmitter for local display. The DO probes will be equipped with an air blast unit to automatically and periodically clean the analyzer probe head.

Instrumentation on the blower discharge header will be provided with remote mount displays for operator ease of use. The flow meters on the MLR recirculation line will have remote mount transmitters, also for operator ease of use.

4.10.2.4 Aeration Blowers
The aeration blowers will be vendor-provided packages, each with a local control panel (LCP) for local operation and monitoring. The vendor will supply a primary blower panel that act as a blower scheduler, handling the number of blowers running and will communicate blower status such as run/stop, faults, and key performance data to the SCADA system.

The control system will send blower discharge header pressure setpoint to the primary blower panel which will communicate to each LCP to achieve the blower pressure output. Redundant pressure transmitters will be provided and wired directly to the blower scheduler PLC to reduce downtime events caused by a transmitter or communication failure. The blower LCPs will provide alarm notifications, such as high pressure or equipment faults, which are relayed to the control system through the primary blower panel for alarm generation.

Blower LCPs
Specifications for the blower LCPs will be provided so that the blower control system follow the standards and guides that will align the programmable logic controller (PLC) hardware, instrumentation, control programming, human-machine interface (HMI) display, and communications to the control system.

4.10.2.5 RAS/WAS Pump Station
The RAS and WAS pumping station will be equipped with magnetic flow meters one each for RAS and WAS discharge. The flow meters will be integrated into the control system for trending and totalization.

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Each pump will be equipped with a VFD and can be locally controlled by a HOA switch. In auto, the pump speeds will modulate to maintain a flow rate setpoint. The control system will receive feedback signals, including pump operational status and VFD pump faults.

4.10.2.6 WAS and Filtrate Storage
An aeration blower will be vendor-provided package, each with a local control panel (LCP) for local operation and monitoring. The blower panel will communicate blower status such as run/stop, faults, and key performance data to the SCADA system. A local RIO rack will be provided to control the valves at the WAS and Filtrate Storage Tank.

The control system will send blower discharge header pressure setpoint to the blower panel to achieve the blower pressure output. The flow control valves will be modulated to set the flow rate based on the level in the tanks. Ultra sonic level transmitters will be specified to read the tank levels at each of the tanks.

4.11 Electrical

4.11.1 Codes, Regulations, and Standards
▪ 2023 National Electrical Code (NEC)
▪ 2024 Life Safety Code (NFPA 101 HB85)
▪ International Fire Code
▪ 2023 National Electrical Safety Code (ANSI C2 2007)
▪ 2024 Standard for Fire Protection in Wastewater Treatment and Collection Facilities (NFPA 820) ▪ ANSI
▪ National Electrical Manufacturers Association (NEMA)
▪ Institute of Electrical and Electronic Engineers
▪ Instrument Society of America (ISA)
▪ Insulated Cable Engineers Association (ICEA)
▪ Occupational Safety and Health Administration
▪ ASTM
▪ Underwriters Laboratory (UL)
▪ Illuminating Engineering Society (IES)
▪ National Fire Protection Association (NFPA)

4.11.2 Distribution System
The WWTP receives its primary electrical power from Pacific Gas and Electric. This utility connection serves as the main source of power for the facility’s operations. The electrical service entrance for the WWTP is designed as an outdoor main switchgear. From the main switchgear, electrical power is distributed to seven existing motor control centers (MCCs) throughout the facility. These MCCs serve as the primary hubs for distributing electrical power to various process equipment and systems throughout the plant.

The MCCs are responsible for controlling and protecting motors, pumps, and other electrical loads essential to the treatment process.

As part of this expansion, the existing MCCs, switchboard, and switchgear will be assessed for spare capacity to determine their ability to support additional electrical loads. This evaluation will also provide a better understanding of existing equipment that is currently operational and in use.

To accommodate new process areas, provide reliable power distribution, and reduce the amount of trenching between facilities, the power distribution system is proposed as follows:

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1. One new MCC will be installed to power the FEB pump station. The new MCC will be near the new pump station. This MCC will be fed from an existing MCC in the admin building.

2. Two new MCCs will be installed to power the aeration basins, chemical storage equipment, blowers, and auxiliary equipment. These MCCs will be fed from the existing MCCs in the operations building, and the loads will be evenly distributed between each new MCC to balance total loading added to the existing system. These MCCs will be near the new aeration blowers.

3. RAS and WAS equipment will be powered from the existing MCCs in the operations building.

These additions will enhance the plant’s operational flexibility and provide adequate electrical capacity for both current and future treatment demands.

4.11.3 Standby Power Distribution System
The WWTP has a co-generation system and an emergency standby generator. These systems will not be altered as part of this Project.

4.11.4 Design Criteria

4.11.4.1 Listed and Labeled Equipment
Electrical equipment, materials, or services to be provided will have an attached label, symbol, or other identifying mark of an organization concerned with product evaluation, compliance with appropriate standards, and equipment performance. Typically, this is the UL label or listing. In situations where a UL label or listing cannot be provided for equipment because of a lack of UL standards, then testing will be performed by an organization that is acceptable to the authority having jurisdiction.

4.11.4.2 Distribution Voltage Selection
Standard distribution systems to be used are as follows:
▪ 480Y/277 volts solidly grounded wye, 3-phase, 4-wire
▪ 208Y/120 volts solidly grounded, 3-phase, 4-wire

4.11.4.3 Utilization Voltages
The equipment utilization voltages listed in Table 4-9 will be used.

Table 4-9. Equipment Utilization Voltages
Equipment Type Value
Lighting 120 volts, single-phase
Convenience Outlets 120 volts, single-phase
Motor Control 120 volts, single-phase
Motors, less than 1/2 hp 115 volts, single-phase
Motors, 1/2 hp and larger 460 volts, three-phase
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4.11.4.4 Voltage Drop
To address voltage drops, the following steps will be taken:
▪ Prepare steady-state voltage drop calculations for all heavily loaded or long branch circuits and feeders.
▪ Use base calculations for motor circuits on the basis of an 80% power factor and loading consistent with the maximum expected peak load (will not include standby motors). ▪ Do not exceed the following total voltage drop from the transformer secondary to the point of utilization, including feeder, branch circuit, and transformation:
- Lighting – 3%
- Motors – 4%
- Receptacles – 4%
- Electric Heaters – 4%

4.11.4.5 Demand Factors
The demand factors listed in Table 4-10 will be used for sizing power switchboards, MCCs, panelboards, and transformers. Connected load will be used for circuit and equipment sizing in accordance with NEC requirements.

Table 4-10. Demand Factors
Service Demand Factor
Lighting 1.0 x Connected Load
Emergency Lighting 1.0 x Connected Load
Air-conditioning Equipment 1.0 x Connected Load
Ventilation Equipment 1.0 x Connected Load
Drainage Pumps and Ejectors 0.50 x Connected Load
Convenience Receptacles 180 VA each*
Process Loads 1 x Full Load Amps of non-standby loads plus 25% of largest motor *Apply NEC demand factor of 50% for totals over 10 kilowatts VA = volt-amperes

4.11.4.6 Branch Circuits
The following criteria are applicable for branch circuits:
▪ Connected load and NEC requirements will be used for sizing branch circuit breakers and conductors. ▪ A minimum wire size of No. 12 American wire gauge (AWG) copper will be used for lighting and receptacle branch circuits. No. 10 AWG will be used when voltage drop requires a larger conductor on lighting circuits, and when receptacle circuits are longer than 75 ft. ▪ In general, lighting branch circuit loads will be limited to 1,500 watts. ▪ Lighting and receptacle branch circuits will not be combined. ▪ The number of convenience receptacles on any one branch circuit will be limited to five duplex in process areas and six duplex in office areas.

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4.11.4.7 Panelboards
The following is applicable for panelboards:
▪ Branch circuits or feeders on the drawings will identify the panelboard and device protecting the individual circuit or feeder.
▪ Each panelboard will be equipped with a minimum of 20% spare breakers with spaces, bus work, and terminations to complete the standard size panelboard.
▪ Panelboard schedules will be prepared indicating the following:
- Circuit identification
- Protective device trip rating
- Number of poles
- Load in volt-amps by phase
- Rating of main lugs or main circuit breaker
- Neutral bus size
- Ground bus size
- Integrated short-circuit rating of the panelboard

4.11.4.8 Motor Control
Elementary (ladder type) control diagrams will be prepared for each motor showing control wiring, pilot devices, auxiliary contacts, and external connections. A single diagram will be used for more than one motor having the same control.

Graphic symbols shown on the electrical legend sheet will be used. Each component will be identified with a unique letter or name. Wiring and devices inside the controller will be shown as solid lines, and wiring and devices remote from the controller will be shown with a dashed line. Remote devices will be indicated by symbol or description.

4.11.4.9 Equipment Identification
Instrumentation and control piping and instrumentation diagram tag numbers will be used for motors, instrumentation and control devices, and other process equipment shown on electrical drawings. This same numbering method will be used to create unique tags for major electrical distribution equipment.

4.11.4.10 Distribution System Equipment
Distribution equipment criteria include the following:

1. Excluding package systems with integral starters, motor starters will be installed in the 480-volt MCCs.

This includes combination across-the-line motor starters, reduced-voltage soft-starts, and VFDs. If supplied, motor circuit protectors will be rated for the available fault current. Starters larger than NEMA size 3 (50 hp) will be the reduced-voltage soft-start type.

2. MCCs will be hardwired to the PLC for software control.

3. MCCs will be sized to accept future loads and either allow for space in the structures or floor space for future sections.

4. 480-volt and 208Y/120-volt power distribution and lighting panelboards with molded case, bolt-inplace and plug-in, respectively, circuit breakers with integrated short-circuit rating suitable for the available fault current.

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4.11.4.11 Raceway Systems
Separate duct banks and maintenance hole networks will be used for the following systems:

1. 480-volt power wiring and 120-volt control wiring
Special consideration will be given to separating raceways involving low-level process control signal wiring and power system wiring to minimize the possibility of interference.

General guidelines for raceway sizing, selection, and installation are given as follows:

1. Conduit sizing will be based on thermoplastic heat and water-resistant (THW) insulation.

2. The following minimum sizes will be used:
a. 3/4-inch minimum diameter for conduit installed exposed on walls and ceilings b. 3/4-inch minimum diameter for conduit concealed in frame construction and finished ceilings c. 1-inch minimum diameter for conduit embedded in masonry, encased in concrete, and underground

3. Raceways will be exposed in process areas.

4. Raceways will be concealed in walls and ceilings in control rooms, offices, and areas that have finished interiors.

5. PVC-coated rigid galvanized steel conduit will be used for the transition from underground direct burial and under slab PVC conduit and concrete-encased (in floor slab) PVC and rigid galvanized steel conduit to exposed rigid galvanized steel conduit. The transition section will extend from 1 ft below grade or top-of-floor slab or the last foot of conduit in the floor slab, to 6 inches out of the floor slab, concrete encasement, or abovegrade.

6. The number of conduit bends will be limited to an equivalent of 270 degrees on long runs without pull boxes.

7. PVC-coated rigid galvanized steel conduit and fittings that are resistant to direct sunlight and include an interior urethane coating will be used in exposed corrosive interior and exterior areas.

8. PVC-coated rigid galvanized steel conduit will be used for underground, direct burial, low-voltage status/control (less than 100 volts) and analog signal circuits.

9. PVC Schedule 40 conduit and fittings will be used for underground direct burial, under slab, and concrete-encased 120-volt circuits.

10. PVC Schedule 40 conduit and fittings will be used for underground concrete-encased 480V power circuits.

11. Rigid galvanized steel conduit and fittings will be used when exposed or concealed in interior, noncorrosive process and nonprocess areas; and in noncorrosive areas outdoors.

12. Flexible, nonmetallic, liquid-tight conduit 4-inch or smaller in size will be used for connections to motors, transformers, and the like, as required. Fittings will be PVC-coated in wet or corrosive areas.

13. Underground conduit routes will be identified with nonmetallic warning tape above underground direct-burial conduits.

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14. Spare raceways will be tagged with a nonferrous metal tag attached to the raceway with a nylon strap.

Raceway tags with approved tag number provided by the contractor will identify the raceway origin and destination and will be located at each terminus, near the midpoint, and at minimum intervals of every 50 ft on exposed raceways (in ceiling spaces and surface-mounted).

4.11.4.12 Wire and Cable
Stranded-copper conductors will be used for all except lighting and receptacle wiring. Solid conductors No. 10 AWG and smaller will be used for lighting and receptacle wiring.

Minimum conductor size of No. 12 AWG will be used for power and lighting branch circuits. Type THHN/THWN-2 insulation will be used for No. 10 AWG and smaller conductors (conduit will be sized for Type THW conductors). Type XHHW-2 insulation will be used for No. 8 AWG and larger conductors (conduit will be sized for THW conductors). For sizing conductors No. 1 AWG and smaller, 60°C conductor ampacity ratings will be used. For sizing conductors larger than No. 1 AWG, 75°C ratings will be used.

Minimum conductor size of No. 14 AWG will be used for individual 120-volt control circuits.

Minimum conductor size of No. 12 AWG will be used for 120-volt control circuits routed in a common conduit with the power conductors to the motor circuit controls. Combining individual motor power and control conductors in a common conduit will be done up to a maximum power conductor size of No. 2 AWG.

Power and control conductors will be color-coded. Conductors No. 8 AWG and smaller will have colored insulation. Conductors No. 6 AWG and larger will be color-coded with tape at each end and at accessible intermediate points.

Conductors and control cables will be tagged with a permanent sleeve or nylon marker plate attached with a nylon strap. Conductor tags with approved tag number will be provided by the contractor and will be located at each termination and in accessible locations.

Under normal conditions, the maximum wire size will be limited to 500 kilo circular mils. Parallel conductors will be used for circuits requiring greater capacity.

Additionally, 120-volt control circuits will be combined in control cables containing multiple No. 14 AWG stranded-copper conductors with type THHN insulation and a common PVC outer jacket.

Further, 600-volt multi-circuit control cable will be used where grouping control circuits is practical, and the number of individual wires exceeds six conductors. When selecting control cable size, 25% spare (plus or minus 10%) conductors will be used.

Multi-conductor control cable color coding will be ICEA S-61 402 Appendix K, Method 1, Table K-2.

Low-voltage status/control (less than 100 volts) and analog signal circuits will be routed in 600-volt, single-twisted, shielded-pair instrumentation control cables. The cables will consist of No. 16 AWG stranded-copper conductors with combination PVC/nylon insulation, drain wire, shield, and PVC outer jacket. Signal circuits will be combined in multi-twisted shielded-pair instrumentation control cables with common overall shield. The cables will consist of No. 18 AWG stranded-copper conductors, with a combination PVC/nylon insulation, pair and common drain wires, pair and common shields, and PVC outer jacket. Instrumentation control cables will be in accordance with ICEA S-82 552. Low-voltage status/control and analog signal circuits will not be routed in the same control cable or conduit with 120-volt control or power circuits. Low-voltage status/control and analog signal circuits will be routed in the same conduit, but not in the same control cable.

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Adjustable frequency drive rated cables will be used between adjustable frequency drives and the driven motor.

4.11.4.13 Circuit Identification
The following steps will be used to identify circuits:
▪ Assign circuit name based on device or equipment at load end of circuit. ▪ Identify circuit at each termination and in accessible maintenance holes and pull boxes. ▪ Use plastic sleeves for conductor No. 3 AWG or smaller and plastic marker plates for larger conductors. ▪ For lighting circuits, identify the panel and circuit number for each fixture.

4.11.4.14 Enclosures
The following summarizes the NEMA categorization for equipment locations:
▪ NEMA 1 enclosures will be used for equipment in electrical rooms and finished areas. ▪ NEMA 12 enclosures will be used for electrical equipment in dry industrial locations. ▪ NEMA 4 enclosures will be used for outside and in wet locations. ▪ NEMA 4X enclosures will be used for corrosive locations.

4.11.4.15 Fiber Optics Cabling
Fiber optic cabling will be installed either in conduit (4-inch-diameter minimum) or in cable trays where applicable. Routing of the raceway system will provide for large radius turns to prevent the fiber optic cable from braking.

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5. Supervisory Control and Data Acquisition System
Section 5 provides details on the SCADA system at the WWTP.

5.1 Control System
The existing control system at the Fortuna WWTP consists of a mix of obsolete Modicon Quantum and Allen-Bradley PLCs with an aging AVEVAHMI. The single HMI workstation is in the operation building.

Modernizing the architecture and wholesale replacement of the plant PLCs and HMI hardware will act as a basis for this design effort. The offsite collection and clean water distribution systems use Tesco PLCs to connect to the existing HMI through a radio network and will be reconnected to the new HMI.

The plant’s standalone HMI workstation is out of warranty and running an operating system and AVEVA InTouch HMI application that is several versions old. Permanent loss of data could occur if the HMI workstation hard drive files or the operating system, software platforms, or programs are corrupted. This workstation is a single point of failure that puts City operations staff at risk of losing visibility of the clean water distribution and wastewater collections systems. It is imperative that a new SCADA system with both hardware and software redundancy be stood up as soon as possible to avoid possible service disruptions and emergency material and labor costs.

The communication infrastructure within the WWTP currently uses a copper-based Modbus Plus serial network that is daisy chained between structures. To develop a more robust and resilient communication system for SCADA components, the media will be replaced with a 24-strand fiber in a physical and topological ring configuration. This will help establish communication resilience within the plant. The control system fiber network will be extended to any new facilities associated with the process improvements. This new fiber network will provide a communication pathway through the plant, of which future projects may use some percentage of the spare fibers. However, this SCADA network is to be strictly segregated from other networked non-SCADA equipment or systems.

The following network-based systems will be connected on the SCADA network:
▪ Antivirus and backup systems
▪ Domain control
▪ Engineering workstations
▪ Historian
▪ Operator workstations (HMI)
▪ PLCs
▪ Any industrial control information system to support one of these functions The following network-based systems will not be directly connected on a SCADA network:
▪ Fire alarm
▪ HVAC
▪ Informational technology platforms
▪ Security cameras
▪ Security systems

5.2 SCADA System Platform Evaluation
The existing PLC hardware is a mix of Schneider Electric and Rockwell Automation hardware. All of the hardware has been discontinued, and the logic contained in the PLCs has years of quick fixes and missing documentation. The current HMI graphics do not follow the industry’s best practices for conveying relevant information to operations and should be updated to follow ISA 18.2 and 101 guidelines.

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Additionally, it will take more time and effort to reuse the old logic and graphics than to write new code using templates that provide efficient coding for both the PLC and HMI. Because the existing SCADA hardware and software is obsolete, no option to replace or upgrade anything in-kind will be presented.

5.2.1 PLC Hardware
The PLC alternatives will be evaluated using the following criteria:
▪ Configuration ease, flexibility, and standardization
▪ Corporate history and stability
▪ Ease of installation and maintenance
▪ Hardware costs
▪ Reliability
▪ Scalability
▪ Security
▪ Technical support and training

5.2.2 HMI Software
The HMI alternatives will be evaluated using the following criteria:
▪ Corporate history and stability
▪ Operator interface
▪ Platform costs
▪ Support from integrators
▪ System scalability
▪ Technical support and training

5.3 SCADA Design Standards
After meeting onsite with plant staff and much internal conversation about the state of the plant control system, the physical space restrictions, and the limited technical support available, it was concluded that the following are the core needs and design principles for the site control system upgrade:
▪ Robust hardware with a small-form factor
▪ Simple configuration and easy replacement
▪ Equipment to be housed inside where possible because of inclement weather Although the SCADA System Upgrade technical memorandum (Jacobs 2024) outlines a very robust control system that would provide a highly resilient control system that would deliver stable operations into the future, there are three primary concerns that led to the decision to implement a simpler design approach:
▪ Limited indoor space for control panel installation
▪ Limited technical resources
▪ Cost of installation and maintenance
Although the components used in the control panel are rated for high humidity, changing sensitive electrical components in the rain or dense fog adds difficulty and risk to the task. Keeping the control panels indoors mitigates the risk and extra time it takes to work in the rain.

Redundant PLCs are more complicated to configure and maintain, and the number of system integrators staff with experience in configuring and maintaining these systems is limited. This will result in longer lead times for maintenance support or multiple trips to site before the issue is resolved.

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The engineer has evaluated the cost difference between Rockwell Automation’s redundant ControlLogix PLC and the simpler CompactLogix PLC systems. The cost of a redundant ControlLogix PLC system is more than two times the CompactLogix system. To mitigate the lack of redundancy, spare hardware will be added to the design so that shelf spares are ready when needed. The new control panel in the operations building will be configured to have a warm standby processor. This way, in the event of a PLC processor failure, the standby processor will be available on the network to except the programming (remote support) and then the onsite staff can replace the failed PLC with the standby processor. The fiber network ring will have redundant network switches at the connection to the SCADA servers. This way, if a break in the ring occurs, the servers will still be connected to the equipment on either side of the network break.

The new SCADA server rack and control panel will be in the operations building. The chief operator’s office will be repurposed as the SCADA server room. These new SCADA servers are noisy and generate additional heat. Modifications to this room to provide independent cooling, better air sealing, and noise mitigation will be part of this design.

To provide the needed resiliency, the SCADA system will use a dual-server architecture with redundant core switches and firewalls. Network attached storage with automated backs will provide a comprehensive backup and disaster recovery. This system will be installed to implement automated backup, which could be used in the case of an anomalous system event.

5.3.1 In-Plant Communications
The existing plant controls networking architecture is based on old design standards and old copper media with a flatter topology. This means the current industrial automation and control systems (IACS) network consists of a single network with open communications between the components of the IACS devices without regards to segmenting the IACS into multiple networks and separating and segmenting traffic for security and data flow efficiency. The basis of design for the new system is to adhere to architectures that align with the latest Purdue Model for IACS, the NIST 800-53 and 800-82 framework, and IEC/ISA 62443. Figure 5-1 shows the logical and conceptual network frameworks.

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Figure 5-1. Logical and Conceptual Network Frameworks
Source: https://www.nist.gov/image/figure-1-purdue-model-computer-integrated-manufacturing The physical network design will completely segment and separate the SCADA/operational technology (OT) environment from enterprise systems and the internet. Figure 5-2 shows separation of the external networks and systems and the plant SCADA environment.

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Figure 5-2. Representation of SCADA Environment Separation from Enterprise Systems and Internet Source: Courtesy of Cisco Systems, Inc. Unauthorized use not permitted. https://www.cisco.com/c/dam/en/us/td/i/200001-300000/250001-260000/256001-257000/256206.jpg.

Image captured June18, 2025.

Figure 5-3 shows the physical hardware topology to meet the logical requirements for the IACS network design in addition to the cybersecurity requirements of separation and segmentation from external systems.

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Figure 5-3. Collapse Core OT Network
Source: Courtesy of Cisco Systems, Inc. Unauthorized use not permitted. https://www.cisco.com/c/dam/en/us/td/i/300001-400000/370001-380000/379001-380000/379814.jpg.

Image captured June 18, 2025.

5.3.2 Control Logic Programming Standards
The development of PLC programming standards is crucial for establishing a framework that allows for modular code, providing operations with consistent control and maintenance features for various equipment such as motors (pumps), valves, and process instrumentation. These standards are designed to promote uniformity in code and tag naming, which is imperative for enabling high-performance HMIs.

Effective alarm management, as outlined in ISA 18.2, begins with well-structured code.

The PLC programming standards will encompass features specific to different equipment types and control algorithms. Additionally, these standards will cover PLC program tag naming conventions and documentation requirements, providing a clear and consistent approach to coding practices. This programming consistency not only facilitates easier maintenance and troubleshooting but also enhances the overall reliability and expandability of the control systems.

5.3.3 HMI Graphic Standards
HMI graphic standards are essential for allowing operators to efficiently and effectively interact with process automation systems. These standards, as outlined by ANSI/ISA-101.01-2015, aim to establish conventions, methodologies, and client-specific standards for developing HMI graphics applications. One of the primary goals of HMI displays is to present the most critical information in an manner that is easily decipherable by the operator. This involves using a color palette to differentiate types of data, with critical issues requiring immediate attention, such as alarms, highlighted in red to draw the operator's focus.

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Traditional HMI displays typically showed values for critical operator parameters, but modern standards emphasize the importance of providing additional context about how these parameters are changing and whether they are within the desirable range. This approach helps operators make more informed decisions, enhancing overall system efficiency and safety. Additionally, the ISA-18.2 standard for alarm management plays a crucial role in enhancing the effectiveness of HMI systems. This standard outlines the processes and procedures required to design, implement, operate, and maintain an effective alarm system. By following ISA-18.2, organizations can manage alarms in a way that improves safety and operational performance, reducing the likelihood of alarm fatigue and giving critical alarms the necessary attention.

The purpose of an HMI graphic standard is to provide a consistent look, feel, and operation across the HMI application, regardless of the development source or project. Graphic standards will be developed to collect and convey accurate information to all users, enabling informed control decisions and supporting the O&M staff in keeping the plant running efficiently. Standards facilitate the expandability and maintenance of HMI systems. Consistent application of these standards means that users can rely on the HMI displays to provide the necessary information for effective plant operation and management, ultimately contributing to the overall success and reliability of the process automation systems.

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6. Permitting
An Initial Study/Proposed Mitigated Negative Declaration document was developed by GHD summarizing the environmental analysis and is provided on Appendix B. The analysis noted that no permits are required for the activities at the WWTP (GHD 2020).

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7. Construction Cost Estimate
A Class 1 cost estimate was prepared in accordance with the guidelines of AACE International. AACE defines Class 1 estimates as the following:

Class 1 estimates are generally prepared to form the basis for budget authorization, appropriation, and/or funding. Typically, engineering is from 70% to 100% complete and would comprise virtually all engineering and design documentation of the project. Typical accuracy ranges for this class estimate are - 3% to -10% on the low side and +3% to +15% on the high side.

The Information Handling Services (IHS) Markit composite cost index tool is used to account for escalation over time.

7.1 Cost Estimate Results
Table 7-1 provides a summary of cost by facility.

Table 7-1. Estimate Summary for City of Fortuna WWTP
Facility Markup Value
Flow Equalization Pump Station and Flow Equalization Basin Liner $5,092,000 Mixed Liquor Distribution Box $655,000
Chemical Storage $1,247,000
Aeration Basins 4 and 5 and PE/RAS Mixing Box $17,612,000 Blower Facility $1,784,000
RAS/WAS Pump Station $2,498,000
MLR Pump Room and Storage Tanks $1,116,000
Operations Building $181,000
Electrical and SCADA Network $1,936,000
Other (site work and yard piping and Strong’s Creek Box) $4,202,000 Subtotal $36,320,000
Construction Contingency (10%) $3,632,000
Subtotal $39,953,000
Project Delivery Costs
Project and Construction Management 5% $1,998,000
Permitting 2% $800,000
Engineering Services During Construction 8% $3,197,000
Commissioning 2% $800,000
Design $5,400,000
SCADA System Upgrade $1,700,000
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Facility Markup Value
Estimated Total Project Cost $53,948,000
Low Range (-10%) Estimated Cost of Construction $48,550,000 High Range (+15%) Estimate Cost of Construction $62,040,000 Funding Application Technical Report Update
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8. References
GHD Group (GHD). 2020. Administrative Draft Initial Study/Proposed Mitigated Negative Declaration. City of Fortuna Wastewater Treatment and Effluent Percolation System Upgrade Project. Prepared for the City of Fortuna. January.

Grady Jr., C.P. Leslie, Glen T. Dagger, Nancy G. Love, and Carlos D.M. Filipe. 2011. Biological Wastewater Treatment. Third Edition. CRC Press.

Jacobs. 2024. Task 2.10 – SCADA System Update. Prepared for the City of Fortuna. July 1.

Jacobs. 2025. Project Definition Report – Final. Prepared for the City of Fortuna. June 5.

Jacobs. 2021. Task 2.1.2 – Process Model Development Technical Memorandum. October 20.

Pease, Michael. 2021. “Purdue Model of Computer Integrated Manufacturing.” Supporting Digital Transformation with Legacy Components. National Institute of Standards and Technology July 20.

SHN Consulting Engineers & Geologists, Inc. 2003. Geotechnical Report – Proposed Additions to Fortuna Wastewater Treatment Plant. November.

SHN Consulting Engineers & Geologist, Inc. 2025. Geotechnical Investigation Data Report, Proposed Wastewater Treatment Plant Improvements – City of Fortuna WWTP, 180 Dinsmore Drive, Fortuna, California; APN 200-353-02.

Appendix A.

New Tagging Standard for
Instrumentation and Equipment
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Tag Number Format: W 3 0 0 P - 3 1 0
New Tag (SCADA)
W100-LIT-120 Influent Pump Station Level Transmitter
W300-P-310 Primary Sludge Pump 1
W300-P-311 Primary Sludge Pump 2
W400-FIT-111 AB 4 Air flow meter
W400-FCV-112 AB 4 Air flow control valve
Collections C 100 440
Facilities F 100 450
Potable Water P 200 460
Wastewater W
210
480
300 490
300 500
300 500
310 600
350 700
400 800
401 850
402
403 900
404 950
405
406
407
AB5
Future AB6
Future AB7
Grit
Flow Equalization
Flow Equalization Basin
Pump Station
Primary Split
Primaries clarifiers
Future AB1
Future AB2
Future AB3
Facility Codes:

Headworks
Chemical Storage Facility
Aeration
AB4
Primary Sludge
PE/RAS Mixing Box
Process Areas:
404-FIT-111 N/A
404-FCV-112 N/A
300-P-310 P-310
300-P-311 P-311
-
New Tag (Field) Existing Tag & Description
100-LIT-120 LIT-120
Facility Code SCADA Area ISA Designator Loop
Tagging Guide Lines / Instrumentation
Part 1 Part 2 Part 3 Part 4
Polymer
Support Facilities
Electrical
Suffix
Process Areas cont'd:

GBT/WAS
Disinfection
Effluent
Plant Water
Digester
Blowers
Secondary Clarifiers
RAS
WAS Storage
BFP
Appendix B.

Administrative Draft Initial Study and
Proposed Mitigated Negative
Declaration
GHD | 718 3rd Street, Eureka CA 95501 | 11146364 | 02 | Report No 1 | January 24, 2020 Wastewater Treatment and Effluent
Percolation System Upgrade Project
Administrative Draft Initial Study & Proposed
Mitigated Negative Declaration
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Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND ADMINISTRATIVE Draft
Initial Study/Proposed Mitigated Negative Declaration
City of Fortuna
Wastewater Treatment and Effluent Percolation
System Upgrade Project
Prepared for:

City of Fortuna
P.O. Box 545
Fortuna, CA 95540
Prepared by:

GHD
718 Third Street
Eureka, CA 95501
January 2020
Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND This page is intentionally left blank
Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page i Table of Contents
Project Information.....................................................................................................................1-0 CEQA Requirements ...................................................................................................... 1-0 Project Background ........................................................................................................ 1-1 Purpose and Need.......................................................................................................... 1-2 Project Location.............................................................................................................. 1-2 Surrounding Land Uses and Existing Setting................................................................. 1-2 Project Description ......................................................................................................... 1-2 Project Construction ....................................................................................................... 1-6 Operation and Maintenance ........................................................................................... 1-8 Environmental Protection Actions Incorporated into the Project.................................... 1-8 Required Agency Approvals ........................................................................................... 1-9 Tribal Consultation.......................................................................................................... 1-9 Environmental Factors Potentially Affected...............................................................................2-1 Environmental Analysis..............................................................................................................3-1 Aesthetics ....................................................................................................................... 3-1 Agriculture and Forest Resources.................................................................................. 3-4 Air Quality ....................................................................................................................... 3-8 Biological Resources .................................................................................................... 3-11 Cultural Resources ....................................................................................................... 3-21 Energy .......................................................................................................................... 3-24 Geology and Soils ........................................................................................................ 3-26 Greenhouse Gas Emissions......................................................................................... 3-30 Hazards and Hazardous Materials ............................................................................... 3-32 Hydrology and Water Quality........................................................................................ 3-36 Land Use and Planning ................................................................................................ 3-41 Mineral Resources........................................................................................................ 3-43 Noise............................................................................................................................. 3-44 Population and Housing ............................................................................................... 3-47 Public Services ............................................................................................................. 3-48 Recreation .................................................................................................................... 3-49 Transportation............................................................................................................... 3-50 Tribal Cultural Resources ............................................................................................. 3-53 Utilities and Service Systems ....................................................................................... 3-55 Wildfire.......................................................................................................................... 3-58 Mandatory Findings of Significance ............................................................................. 3-59 References.................................................................................................................................4-1 Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page ii Report Preparers .......................................................................................................................5-1 City of Fortuna ................................................................................................................ 5-1 GHD................................................................................................................................ 5-1 Sub-consultants.............................................................................................................. 5-1 Table Index
Table 3.3-1 Construction Regional Pollutant Emissions......................................................................3-10 Table 3.13-1: Construction Equipment Reference Noise Levels as Measured at 50’ .........................3-45 List of Figures
Figure 1 Vicinity Map
Figure 2 Project Overview
Figure 3 Prime Agriculture Soils
Appendix Index
Appendix A Air Quality Modeling Results
Appendix B Biological Resources Report
Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 1-0 Project Information
Project Title Wastewater Treatment and Effluent Percolation System Upgrade Project
Lead Agency Name & Address City of Fortuna
621 11th Street
P.O. Box 545
Fortuna, CA 95540
Contact Person & Phone Number Merritt Perry, City Manager, (707) 725-1410 Project Location Fortuna and Humboldt County, CA
Project Sponsor’s Name & Address City of Fortuna
621 11th Street
P.O. Box 545
Fortuna, CA 95540
General Plan Land Use Designation Fortuna WWTP: Public (PUB) Contingency Mid-River Drilling Point: Natural Resources (NR)
Percolation Field: Agriculture Exclusive (AE)
Zoning Fortuna WWTP: Public Facilities (PF)
Contingency Mid-River Drilling Point: Natural
Resources, Streams and Riparian Corridors Protection
(NR/R)
Percolation Field: Agriculture Exclusive, Archeological Resource Area, Streams and Riparian Corridors Protection, Transitional Agricultural Lands (AE-60/A, F, R, T)
CEQA Requirements
This project is subject to the requirements of the California Environmental Quality Act (CEQA). The lead agency is the City of Fortuna (City). The purpose of this Initial Study is to provide a basis for deciding whether to prepare an Environmental Impact Report, a Mitigated Negative Declaration or a Negative Declaration. This Initial Study is intended to satisfy the requirements of the California Environmental Quality Act, CEQA, (Public Resources Code, Div 13, § 21000-21177), and the CEQA Guidelines (California Code of Regulations, Title 14, § 15000-15387). CEQA encourages lead agencies and applicants to modify their projects to avoid significant adverse impacts. § 15063(d) of the State CEQA Guidelines states the content requirements of an Initial Study as follows:

1. A description of the project including the location of the project; Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 1-1

2. An identification of the environmental setting;

3. An identification of environmental effects by use of a checklist, matrix, or other method, provided that entries on a checklist or other form are briefly explained to indicate that there is some evidence to support the entries;

4. A discussion of the ways to mitigate the significant effects identified, if any;

5. An examination of whether the project would be consistent with existing zoning, plans; and other applicable land use controls;

6. The name of the person or persons who prepared or participated in the Initial Study.

Project Background
The City’s Wastewater Treatment Plant (WWTP) is regulated under the North Coast Regional Water Quality Control Board (NCRWQCB), and operates under waste discharge requirements issued by the NCRWQCB in Order No. R1-2017-0005, effective November 1, 2017.

The WWTP has a permitted dry weather average daily flow (ADF) capacity of 1.5 Million Gallons per Day (MGD), and wet weather ADF capacity of 7.0 MGD. According to the 2017 Annual Report (City of Fortuna 2018), the WWTP operates at an average dry weather flow of 0.760 MGD, and, during wet weather, can experience flows above 4.5 MGD. Peak influent flows over 3 to 4 MGD are diverted to equalization ponds and returned for treatment during lower flow periods. The WWTP currently treats an ADF of approximately 1.0 MGD (accounting for both dry weather and wet weather conditions). Approximately 90% of the connections to the collection system are residential and commercial users; the remaining 10% are industrial. The WWTP was originally constructed in 1974 under the City of Fortuna Water Pollution Control Facilities Project. In June 2007, an upgrade was completed to provide additional primary treatment, secondary clarification and a solids handling facility. The existing liquid treatment facilities include screening, grit removal, equalization, primary clarification, secondary biological treatment, secondary clarification, and chlorination/dechlorination.

The treated effluent is discharged to the Eel River or percolation ponds, depending on the time of year. From May 15th through September 30th, the City is prohibited from discharging treated effluent to the Eel River, and discharges to two percolation ponds, which allow disposal through infiltration into groundwater. The percolation ponds are located approximately 180 feet from the edge of the Eel River. From October 1st through May 14th, treated effluent is discharged into either the percolation ponds or Strongs Creek, a tributary of the Eel River. Studies have shown that there is the potential for hydraulic connection between the existing percolation ponds and the Eel River.

The Regional Board has required the City to implement an alternative method of summertime effluent disposal due to potential connectivity during periods when river discharge is not allowed.

The Regional Board is also requiring the City to upgrade the treatment system to improve treatment for ammonia and nitrate. As a result, the City must implement alternative methods of effluent disposal or reuse during the period May 15th through September 30th and upgrade the treatment system.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 1-2 Purpose and Need
The City obtained funding through the Clean Water State Revolving Fund (CWSRF) for planning of the Wastewater Treatment and Effluent Percolation System Upgrade Project (project). The objective of the project is to address compliance issues related to the disposal of treated effluent and construct a new disposal system to replace the historic May 15th through September 30th use of the WWTP percolation ponds. This will avoid the potential connection to the Eel River during the discharge prohibition period.

The City previously evaluated wastewater treatment, disposal, and reuse alternatives to address the compliance requirements related to the City’s discharge permit issued by the Regional Board. A number of alternatives were evaluated. The preferred alternative (the project) includes upgrade of the WWTP within the existing developed site to add Biological Nutrient Removal (BNR) and development of a treated effluent subsurface percolation facility (percolation field) on the opposite (western) side of the Eel River. The new percolation facility is located approximately 2,800 feet from the water’s edge during low flow conditions. This site is more than 15 times further from the river than the existing percolation ponds and thus has much greater hydrologic separation from the Eel River. Under the proposed project, treated effluent would be pumped from the existing treatment plant under the Eel River through a new, directionally-drilled pipeline.. A new pump station and piping modifications at the treatment plant would be required, along with a network of subsurface percolation pipes at the percolation site.

Project Location
The treatment upgrades would all be completed within the footprint of the existing developed WWTP. The new effluent percolation system would be located on the western side of the Eel River, opposite Fortuna, California (see Figure 1). The nearest roads are Pleasant Point Road and Renner Lane (see Figure 2). The new percolation field would be located on APN 106-091-030 and 106-091-040 currently owned by Troy Land and Trudy Ehmke. A temporary construction easement would be needed for APN 106-041-016 owned by Lester Pedrazzini, for the drill exit pit and pipe trenching. The new percolation field would be connected to the existing WWTP via the new pipeline directionally drilled under the Eel River.

Surrounding Land Uses and Existing Setting
The eastern project area consists of the existing WWTP. Surrounding land uses are a combination of heavy industrial (gravel operations) and commercial (wholesale/retail horticulture products).

Highway 101 is located to the east, and the Eel River is located to the west.

The western project area consists of the new effluent percolation fields. The site of the proposed percolation fields is generally surrounded by riparian forest land and open gravel bar areas used for four-wheel drive recreation. The site is bordered to the southeast by agricultural fields.

Project Description

1.6.1 Establish Site Access
The overall site for the new effluent percolation field is comprised of 60 acres that are generally located along the Eel River. Soils within the proposed site are primarily classified as Water and Fluvents, which is reflective of the historical movement of the Eel River in the area. Slopes range Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 1-3 from 0 to 2 percent. The western and southern portions of the site are classified as Udifluvents. The soil classifications are sourced from the most current USDA Natural Resources Conservation Service Web Soil Survey for Humboldt County (NRCS 2019).

According to the Humboldt County General Plan, the parcels are primarily zoned agriculture exclusive (AE) with the eastern edge of the parcels zoned natural resources (NR), both with combining overlays. The project site is located in the coastal zone and includes both State Coastal Jurisdiction and Local (Humboldt County) permit jurisdiction.

Site access to both the existing treatment plant as well as the new percolation field would be required for construction and ongoing operations. Existing roads would be used to access the WWTP.

The horizontal directionally drilled pipeline would be installed from the western side of the Eel River at the percolation field site. There would be up to three directional drill pits, including one main inlet pit, one main outlet pit, and, potentially, a third contingency inlet/outlet pit mid span, located on the Eel River floodplain. The main inlet pit would be located on the western side of the Eel River at the percolation field site. Existing farm roads off of Renner Lane would be utilized to provide site access to the main inlet pit on the western side of the Eel River at the percolation field. The existing farm roads would require minor grading and would be extended.

One drill pit would be located on the eastern side of the Eel River at the WWTP. Two potential western drill pit locations have been identified (see Figure 2; Option A, within an existing equalization basin at the WWTP, and Contingency B, just north of the WWTP). Existing access to the WWTP area would be used on the eastern side off of Dinsmore Drive.

A third drill pit may be installed along the pipe alignment if required by actual drilling conditions and would be accessed via existing unimproved roads along the Eel River gravel bar.

1.6.2 Improvement of Western Access Road
The existing farm road off Renner Lane is a dirt and gravel road that would be graded, and additional gravel would be placed and compacted to provide access to the treated effluent percolation field site. The improved access road would be approximately 15 feet wide by 5,150 feet long and would remain unpaved. The City of Fortuna would procure an easement or other legal right through the private property to provide access to the percolation field area.

1.6.3 Conveyance Pipe Connecting Existing WWTP and New Percolation Field
The new conveyance pipe would connect to the WWTP at an existing concrete wet well structure, which currently contains the City’s treated effluent pumps for emergency discharge to Strongs Creek during high flows. The new connection at the WWTP existing concrete wet well would include piping, pump installation, electrical connections, and installation of piping and fittings in the bottom of the earthen basin. Across the Eel River at the percolation field, there would be new piping fittings, and related appurtenances only.

The new conveyance pipe would be directionally drilled approximately 20 feet to 40 feet below the Eel River and 10 feet to 20 feet below Strongs Creek. The length of the directional drilling route would be approximately 4,800 feet. A drill pit would be required at the WWTP side and the Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 1-4 percolation field side. A third drill pit location may be utilized along the pipeline route and outside of the Eel River active channel if required by the actual drilling conditions and the contractor’s means and methods. The eastern pit would provide piping connectivity to the existing WWTP. The eastern pit location includes Option A, within an existing equalization basin at the WWTP, and Contingency B, just north of the WWTP (see Figure 2). The western pit would provide connectivity to the new percolation field.

A Horizontal Directional Drilling Hydrofracture Contingency Plan would be prepared to ensure that the potential for contamination of the surrounding area from drilling slurry is minimized and that contingency methods are in place in the event that the slurry is introduced into surface waters.

A linear pipe staging area is planned to the west of the percolation field along existing agricultural field fence lines. The pipe would be laid out in its entirety and fed into the directionally drilled inlet pit at the percolation field until it reaches the drill pit at the WWTP.

1.6.4 Effluent Percolation System
The new percolation system would be located on an approximate 2.0 acre portion of the upper river bar that is currently undeveloped (Figure 2). The river bar and future percolation area are used informally for off-road vehicle recreation. The percolation area is relatively open and is covered with seasonal grasses as well as occasional shrubs and trees. Off-road vehicles have heavily impacted the area, which is scarred with numerous vehicle trails and depressions. Areas surrounding the subsurface percolation site are characterized by areas of denser stands of riparian vegetation including cottonwood trees and willows. Historically, the proposed percolation area may have been riparian forest similar to the surrounding habitat, and subsequently cleared, although no historical photos observed show previous forest in the percolation area.

Construction of the percolation system would include: site grading and vegetation removal; trenching for transmission and infiltration pipes; and installation of valve boxes, cleanouts, and monitoring wells. Existing vegetation would be removed during grading and trenching, and seeded upon completion.

The new percolation system would distribute secondary treated effluent through a network of perforated pipes in trenches filled with porous gravel. The new percolation system would be designed for a maximum month average summer flow of 1.3 MGD with flexibility to expand in the future if needed.

The system was sized based on the results of field investigations and soils testing, field percolation testing, and laboratory testing using U.S. Environmental Protection Agency methods to guide the analysis and sizing of the system.

The primary percolation area would likely consist of two sets of 16 parallel pipes which are 2 inches in diameter, 100 feet long each, and perforated with 3/16 inch holes. The perforated pipes would be installed in infiltration trenches. These pipes would be connected through a manifold with isolation valves to control water to the pipes in pairs. Isolation valves would be installed in concrete boxes with lockable lids. A second identical reserve field would also be constructed as part of the initial project to support the existing WWTP effluent flows. The configuration allows for the potential to extend headers and install additional perforated piping if needed for future flows. It is expected that future extensions would have a similar configuration as proposed for the current project.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 1-5 Typically half of the infiltration lines would be in service at any one time, and able to infiltrate the maximum month average summer flow of 1.3 MGD. The use of the lines would be rotated periodically to allow them to rest. The rotation of the percolation system lines would be operated manually through the use of isolation valves without the need for electrical systems. Isolation valves would be installed to switch between main fields and to control pairs of infiltration lines in use.

No chemicals would be used at the percolation field.

1.6.5 WWTP Treatment Upgrades: Non-Proprietary Biological Nutrient Removal (BNR) Improved Secondary Treatment and Ultraviolet Disinfection
The City is required to meet effluent targets per the NPDES permit issued by the Regional Board.

The City’s NPDES permit currently required the City to upgrade the treatment system for improved removal of ammonia and nitrate. The City is proposing to add Biological Nutrient Removal (BNR) to the existing treatment train, which would include converting the aeration basins to the Modified Ludzack Ettinger (MLE) process, as well as modifying the waste activated sludge (WAS) and filtrate equalization (EQ) basins.

A phased construction approach would be used for the WWTP upgrades to allow the WWTP to stay in operation during construction. The construction to modify the WWTP to include the MLE process would consist of the following elements:
• Construction of a new aeration basin distribution box; • Sequentially converting aeration basins one at a time; • Implementing new dissolved oxygen (DO) control for each new basin as it comes online; • Installation of motorized inlet valves;
• Connecting each basin to new distribution box as it is brought online; and • Building an optional supplemental carbon storage tank.

The upgrade to the WAS and filtrate EQ basins includes the following:
• Demolition of some of the existing compost storage and construction of new compost storage;
• Construction of new WAS and filtrate EQ tanks;
• Connection of existing WAS and filtrate piping;
• Converting existing WAS and filtrate EQ tanks to expanded aeration tanks; • Aligning the new aeration tanks with the existing three aeration basins; and • Connecting the expanded aeration basins in sequence with the corresponding MLE tanks.

WWTP treatment upgrades may also include the addition of ultraviolet (UV) disinfection. If UV disinfection is implemented, iron that is present in the treated effluent can foul the UV bulbs and replace with text
provided
Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 1-6 reduce the effectiveness over time. Therefore, an aluminium-based metal coagulant such as alum, sodium aluminate or polyaluminum chloride (PAC) may be used operationally.

1.6.6 Revegetation
Following construction, the percolation field area would be replanted with appropriate grass species. Additional areas outside of the percolation area may be planted with trees or other vegetation to develop additional riparian habitat and provide buffer and screening areas. Vegetation would generally not be removed at the WWTP facility; although disturbed ground would be reseeded, as has been the practice with previous WWTP upgrade projects.

Project Construction

1.7.1 Construction Schedule
Construction is anticipated to occur over an eight-month construction window planned to commence during a single construction season (2021, 2022, or 2023). Anticipated daytime work hours are 7:00 a.m. to 7:00 p.m., Monday through Friday with occasional work on Saturdays.

Construction on Sunday or legal and county holidays is not currently anticipated, except for emergencies or with prior approval from the City.

1.7.2 Construction Staging, Activities, and Equipment
Staging areas would be located at the existing WWTP and around the new percolation area. The approximate dimensions of the staging area at the WWTP would be 250 feet by 450 feet, and 350 by 150 feet staging area for the treatment upgrades. The staging area near the percolation field would be approximately 600 feet by 700 feet. The staging for the directionally drilled-pipeline would be roughly 4,300 feet long by 20 feet wide and extend along the edge of existing agricultural fields.

See Figure 2 for all staging locations.

Excess soils and construction materials would be stored on site within previously designated staging areas only. Excess soils may be re-used on site for backfill and finished grading. Excess soils would not be stockpiled on-site once the project is complete. The contractor may haul additional excess soils off site for use at other permitted sites.

Construction would primarily include site preparation such as trimming and/or removal of trees and vegetation, excavation and grading, open trench pipe installation, gravel access, roadway development, directional drilling, monitoring well installation, and final site grading and revegetation.

Water from permitted sources would be used for dust control and compaction and re-vegetation.

All construction activities would be accompanied by both temporary and permanent erosion and sediment control best management practices (BMPs). Project construction would include the following activities:
• Directional drilling – To install the new subsurface transmission piping under the Eel River; • Clearing and grubbing – To clear trees, vegetation and topsoil from the proposed treatment area and access road;
• Grading – Minor trenching for piping surface leveling and grading; • Excavation – Primarily at shallow excavations to maintain design grades; Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 1-7 • Embankment – Fill to maintain design grades through low areas; • Aggregate base – For the existing and extended access road; • Trenching – For the installation of piping including importing river run for trench backfill; • Demolition– For the treatment upgrades at the WWTP, including demolition of the compost storage;
• Structure Erection – For the WWTP treatment upgrades, including construction of an aeration basin distribution box, a carbon storage tank, and new compost storage; • Tank Erection – For the WWTP treatment upgrades and modifications to the existing WWTP.

Equipment required for construction would include: tracked excavators, backhoes, graders, bulldozers, dump trucks, vertical monitoring well drill rig, pipe drilling equipment, pipe fusing equipment, water trucks, bobcat, and pick-up trucks. It is not anticipated that any temporary utility extensions, such as electric power or water, would be required for construction.

1.7.3 Traffic and Access Control
The anticipated access route to the new effluent percolation field would be Highway 211 near Ferndale, California. Local roads then connect Waddington Road to Pleasant Point Road. The access road along existing farm roads would connect to Pleasant Point Road and Renner Lane and provide access to the site. Construction-related traffic would be limited to equipment mobilization at the new waste water disposal area and daily personnel travel. Due to the rural nature of the area, existing low levels of traffic, and anticipated low levels of construction-related traffic, the need for formal traffic control is not anticipated.

Secondary access is also available along multiple existing unimproved gravel roads near the Eel River floodplain departing from East Ferry Road. Floodplain access may be utilized to support the mid-point directional drilling location depending on the contractor’s means and methods.

1.7.4 Groundwater Dewatering
Groundwater dewatering is generally not expected to be required. However, if needed, temporary groundwater dewatering would involve pumping water out of a trench or excavation. Groundwater would typically be pumped to a settling pond, Baker tanks (or other similar type of settling tank), or into a dewatering bag. Dewatering water may also be percolated back into the ground (in uplands) or used for dust control and compaction, or re-vegetation irrigation.

1.7.5 Site Restoration and Closure
Following construction, the contractor would demobilize and remove equipment, supplies, and construction wastes. The disturbed areas would be restored to pre-construction conditions or stabilized with a combination of grass seed (broadcast or hydroseed), straw mulch, rolled erosion control fabric, and/or other plantings/vegetation.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 1-8 Operation and Maintenance
Maintenance and operation of the new treated effluent percolation system would generally require the following:
 Access road maintenance including periodic blading and grading and addition of gravel;  Ongoing monitoring of the system per the permit requirements;  Periodic site observation and operation of valves to rotate active fields;  Vegetation management;
 Groundwater sampling;
 General WWTP equipment maintenance;
 Use of an aluminium-based metal coagulant to support UV disinfection at the WWTP, and  Use of supplemental carbon for the nitrification reaction at the WWTP.

Operationally, pumping would be required to transport up to a monthly average of 1.3 MGD of treated effluent through the underground pipe to the opposite bank of the Eel River during the summer time subsurface effluent percolation period from May 15th through September 30th. Three 10 to 20 horsepower pumps would be used for pumping, although a maximum of two of the pumps would typically be in service at any one time.

Environmental Protection Actions Incorporated into the
Project
The following actions are included as part of the project to reduce or avoid potential adverse effects that could result from construction or operation of the project. Additional mitigation measures are presented in the following analysis sections in Chapter 3, Environmental Analysis. Environmental protection actions and mitigation measures, together, would be included in a Mitigation Monitoring Program at the time that the project is considered for approval.

1.9.1 Environmental Protection Action 1 – Implement Geotechnical Design Recommendations
As part of the project design process, the City would engage a California-registered Geotechnical Engineer to conduct a design-level geotechnical study for the project. The City would design the project to comply with the site-specific recommendations made in the project's geotechnical report.

The report would include seismic and foundation design criteria, technical requirements for direction drilling, as well as for site preparation and grading. The geotechnical recommendations would be incorporated into the final plans and specifications for the project, and would be implemented during construction.

1.9.2 Environmental Protection Action 2 – Stormwater Pollution Prevention Plan (SWPPP)
The project would seek coverage under State Water Resources Control Board (Water Board) Order No. 2009-0009-DWQ, Waste Discharge Requirements for Discharges of Storm Water Runoff Associated with Construction and Land Disturbance Activities. The City would submit permit registration documents (notice of intent, risk assessment, site maps, SWPPP, annual fee, and Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 1-9 certifications) to the Water Board. The SWPPP would address pollutant sources, best management practices, and other requirements specified in the Order. The SWPPP would include erosion and sediment control measures, and dust control practices to prevent wind erosion, sediment tracking, and dust generation by construction equipment. A Qualified SWPPP Practitioner would oversee implementation of the project SWPPP, including visual inspections, sampling and analysis, and ensuring overall compliance.

Required Agency Approvals
The following permits and approvals are likely to be required prior to construction:
 Humboldt County – Encroachment, Grading, and Conditional Use Permits;  North Coast Regional Water Board (NCRWB, or Regional Board) Clean Water Act Section 401 certification (if impacts to Waters or wetlands would occur);  Construction stormwater discharge permit (National Pollutant Discharge Elimination System) from the State Water Resources Control Board;
 Approval of State Revolving Fund application and initiation of consultation with applicable federal agencies with the State Water Resources Control Board Division of Financial Assistance;  U.S. Army Corps of Engineers (USACE) Clean Water Act Section 404 permit (if impacts to Waters or wetlands would occur);
 California Department of Fish and Wildlife (CDFW) Streambed Alteration Agreement;  Coastal Commission Coastal Development permit;
 State Lands Commission lease or permit.

Tribal Consultation
The City has received requests for notification of proposed projects from California Native American tribes pursuant to Public Resources Code Section 21080.3.1. Under Assembly Bill (AB) 52, notification letters were sent to local Native American tribes on January 13, 2020. No response has been received at this time.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 2-1 Environmental Factors Potentially Affected
The environmental factors checked below would be potentially affected by this project, involving at least one impact that is a “Potentially Significant Impact” as indicated by the checklist on the following pages. Where checked below, the topic with a potentially significant impact would be addressed in an appropriate environmental document:

Aesthetics Greenhouse Gas
Emissions
Public Services
Agricultural & Forestry
Resources
Hazards & Hazardous
Materials
Recreation
Air Quality Hydrology/Water Quality Transportation
Energy Land Use/Planning Tribal Cultural Resources
Biological Resources Mineral Resources Utilities/Service Systems Cultural Resources Noise Wildfire
Geology/Soils Population/Housing Mandatory Findings of
Significance
DETERMINATION (To be completed by the Lead Agency)
On the basis of this initial evaluation:

I find that the proposed project COULD NOT have a significant effect on the environment, and a NEGATIVE DECLARATION would be prepared.

I find that although the proposed project could have a significant effect on the environment, there would not be a significant effect in this case because revisions in the project have been made by or agreed to by the project proponent. A MITIGATED NEGATIVE DECLARATION would be prepared.

I find that the proposed MAY have a significant effect on the environment, and an ENVIRONMENTAL IMPACT REPORT is required.

An ENVIRONMENTAL IMPACT REPORT is required, but it must analyze only the effects that remain to be addressed.

I find that the proposed project MAY have a “potentially significant impact” or “potentially significant unless mitigated” impact on the environment, but at least one effect: (1) has been adequately analyzed in an earlier document pursuant to applicable legal standards, and (2) has been avoided or mitigated pursuant to that earlier EIR or NEGATIVE DECLARATION, including revisions or mitigation measures that are imposed upon the proposed project, nothing further is required. _______________________________ ____________________
City of Fortuna Signature Date
Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 2-2 This page is intentionally left blank
Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-1 Environmental Analysis
Aesthetics
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Except as provided in Public Resources
Code § 21099, would the project:
a) Have a substantial adverse effect
on a scenic vista? 
b) Substantially damage scenic
resources, including, but not limited
to, trees, rock outcroppings, and
historic buildings within a state
scenic highway?

c) In non-urbanized areas,
substantially degrade the existing
visual character or quality of public
view of the site and its
surroundings? (Public Views are
those that are experienced from
publicly accessible vantage point).

If the project is in an urbanized
area, would the project conflict with
applicable zoning and other
regulations governing scenic
quality?

d) Create a new source of substantial
light or glare which would adversely
affect day or nighttime views in the
area?

Visual resources within the project area east of the Eel River include the WWTP. Visual resources within the project area west of the Eel River include rural pastoral and riparian forest views, and western views into the coastal mountain foothills. The project area also includes the Eel River floodplain in the location of a potential directional drilling inlet/outlet (Figure 2 – Project Study Area).

Project activities include construction at the existing WWTP to provide treatment upgrades as well as construction of a new percolation system on the west side of the Eel River. An underground pipe would be directionally drilled under the Eel River to connect the two facilities and would not be visible, outside of temporary construction and staging for drill rigs. a) Have a substantial adverse effect on a scenic vista? (Less Than Significant Impact) The WWTP is located between Highway 101 and the Eel River. Planned treatment upgrades at the WWTP would not alter the existing visual character of the WWTP or the view within the vicinity of the project. Construction-related visual impacts related to WWTP treatment upgrades and the directionally drilled pipeline would be short-term. If vegetation mapped as ESHA is removed to develop the directional drilling pits (Contingency B only), revegetation of ESHA or re-seeding of appropriate species for erosion control best management practices (BMPs) would occur; thus visual change would be temporary until vegetation reestablishes at the Contingency B drill pit.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-2 The percolation field is located in an upland area west of the Eel River, adjacent to privately owned farm land. The percolation field is not visible from a public road. The percolation field and associated improved and extended access road is near a single residence; the landowner is a project cooperator and would enter into a site access agreement with the City to support both construction and operational use.

Due to its elevation, the percolation field is also not visible from the Eel River or floodplain. In its existing condition, the percolation field area is scarred by off-road vehicle trails and has been largely denuded of riparian vegetation, impairing the visual character of the area. Construction would be generally limited to a two-acre footprint. Vegetation mapped as ESHA removed to accommodate construction would be replanted in accordance with requirements established by the California Coastal Commission (CCC) and the California Department of Fish and Wildlife (CDFW).

Visual impacts related to construction would be temporary.

All project elements related to directional drilling and the percolation field would occur almost entirely underground and would not be visible upon completion of construction The project does not include elements or structures with any height of significance that could impede viewsheds or scenic vistas. There would be no operational effect on a scenic vista. The impact would be less than significant.
b) Substantially damage scenic resources, including, but not limited to, trees, rock outcroppings, and historic buildings within a state scenic highway? (No Impact) The project is not located within or near a state scenic highway (Caltrans 2019). The project area does not include any historic trees or rock outcroppings. The only buildings within the project area are those located at the WWTP, which are not historic. There would be no impact. c) In non-urbanized areas, substantially degrade the existing visual character or quality of public view of the site and its surroundings? (Public Views are those that are experienced from publicly accessible vantage point). If the project is in an urbanized area, would the project conflict with applicable zoning and other regulations governing scenic quality? (Less Than Significant Impact) The percolation field is located in a non-urbanized area but is not visible by the public or via a public roadway/vantage point. The percolation field is located in a visually impacted area, scarred by offroad vehicle trails. Significant portions of riparian vegetation have been degraded and removed as a result of off road vehicle use.

Site access to the eastern project area is consistent with the Eel River Area Local Coastal Plan (Section 3.41 (B) (1) (b)), which requires permitted landform alteration for access roads and public utilities to be minimized along natural corridors (Humboldt County 2014). Development of the percolation field and associated site access would be both minimal and consistent with existing site topography and visual character.

Any visual impacts related to construction would be temporary. Vegetation removed during construction would be replanted. Site access would be accomplished via an existing access road that would remain unpaved, and be extended slightly along an existing fence line in an area that is not visible to the public. Once complete, the project is likely to improve the visual character of the percolation field, which would largely include only underground infrastructure. Off-road-vehicle trails would be removed and vegetative cover surrounding the construction footprint is likely to improve as a result of planned revegetation efforts. The impact would be less than significant.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-3 d) Create a new source of substantial light or glare which would adversely affect day or nighttime views in the area? (No Impact)
The project does not include any temporary or permanent sources of light. There would be no impact.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-4 Agriculture and Forest Resources
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
a) Convert Prime Farmland, Unique
Farmland, or Farmland of Statewide
Importance (Farmland), as shown on
the maps prepared pursuant to the
Farmland Mapping and Monitoring
Program of the California Resources
Agency, to non-agricultural use?

b) Conflict with existing zoning for
agricultural use, or a Williamson Act
contract?

c) Conflict with existing zoning for, or
cause rezoning of, forest land (as
defined in Public Resources Code §
12220(g)), timberland (as defined by
Public Resources Code § 4526), or
timberland zoned Timberland
Production (as defined by Government
Code § 51104(g))?

d) Result in the loss of forest land or
conversion of forest land to non-forest
use?

e) Involve other changes in the existing
environment which, due to their
location or nature, could result in
conversion of Farmland, to nonagricultural use or conversion of forest land to non-forest use?

Western project areas at the location of the percolation field, including associated access and staging areas, are zoned AE. The location of the potential contingency floodplain mid-point directional drilling inlet/outlet pit is also zoned AE/NR (Humboldt County 2019). The WWTP is zoned Public Facilities (PF) and does not include agricultural or forest resources. a) Convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance)? (Less than Significant Impact)
Appendix G to the CEQA Guidelines suggests a finding of significance if a project would convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance (Farmland), as shown on the maps for the Farmland Mapping and Monitoring Program (FMMP) by the California Natural Resources Agency (California Department of Conservation [DOC]), to non-agricultural uses. The project area does not contain Unique Farmland or Farmland of State Importance as shown on the maps prepared pursuant to the FMMP of the DOC, as soil data in Humboldt County has not been compiled into the FMMP (DOC 2019). However, the project area does include soils mapped as 132 – Udifluvents, which have been categorized as prime farmland if irrigated or drained (NRCS 2019). As such, this analysis assumes prime farmland present in some western project areas (see Figure 3 – Prime Agricultural Soils).

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-5 Eel River Area Local Coastal Plan
The Eel River Area Local Coastal Plan (Humboldt County 2014) includes the following applicable policies regarding agricultural lands:
 3.34 (f): By assuring that public service and facility expansions and nonagricultural development do not impair agricultural viability, either through increased assessment costs or degraded air and water quality.
 3.34 F: Public acquisition of lands designated Agriculture Exclusive shall be from willing sellers only.

Humboldt County
The Humboldt County General Plan (2017) includes the following applicable policies regarding agricultural lands:

AG-G2. Preservation of Agricultural Lands
Agricultural land preserved to the maximum extent possible for continued agricultural use in parcel sizes that support economically feasible agricultural operations.

AG-P5. Conservation of Agricultural Lands
Agricultural lands shall be conserved and conflicts minimized between agricultural and nonagricultural uses through all of the following:

A. By establishing stable zoning boundaries and buffer areas that separate urban and rural areas to minimize land use conflicts.

B. By establishing stable Urban Development, Urban Expansion and Community Planning Areas and promoting residential in-filling of Urban Development Areas, with phased urban expansion within Community Planning Areas.

C. By developing lands within Urban Development, Urban Expansion and Community Planning Areas prior to the conversion of agricultural resource production lands (AE, AG) within Urban Expansion Areas.

D. By not allowing the conversion of agricultural resource production lands (AE, AG) to other land use designations outside of Urban Expansion Areas.

E. By assuring that public service facility expansions and non-agricultural development do not inhibit agricultural viability, either through increased assessment costs, degradation of the environment, land fragmentation or conflicts in use.

F. By increasing the effectiveness of the Williamson Act Program.

G. By allowing historical structures and/or sensitive habitats to be split off from productive agricultural lands where it acts to conserve working lands and structures.

H. By allowing lot-line adjustments for agriculturally designated lands only where planned densities are met and there is no resulting increase in the number of building sites.

AG-P6. Agricultural Land Conversion – No Net Loss
Lands planned for agriculture (AE, AG) shall not be converted to non-agricultural uses unless the Planning Commission makes the following findings:

A. There are no feasible alternatives that would prevent or minimize conversion; Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-6 B. The facts support an overriding public interest in the conversion; and C. For lands outside of designated Urban Development Boundaries, sufficient off-setting mitigation has been provided to prevent a net reduction in the agricultural land base and agricultural production. This requirement shall be known as the “No Net Loss” agricultural lands policy. “No Net Loss” mitigation is limited to one or more of the following:

1. Re-planning of vacant agricultural lands from a non-agricultural land use designation to an agricultural plan designation along with the recordation of a permanent conservation easement on this land for continued agricultural use; or

2. The retirement of non-agricultural uses on lands planned for agriculture and recordation of a permanent conservation easement on this land for continued agricultural use; or

3. Financial contribution to an agricultural land fund in an amount sufficient to fully offset the agricultural land conversion for those uses enumerated in subsections a and b.

The operational details of the land fund, including the process for setting the amount of the financial contribution, shall be established by ordinance.

AG-P16. Protect Productive Agricultural Soils
Development on lands planned for agriculture (AE, AG) shall be designed to the maximum extent feasible to minimize the placement of buildings, impermeable surfaces or nonagricultural uses on land as defined in Government Code Section 51201(c) 1- 5 as prime agricultural lands.

AG-S7. Prime Agricultural Land.

Prime Agricultural land per California Government Code Section 51201(c) means:

A. All land which qualifies for rating as Class I or Class II in the Soil Conservation Service land use capability classifications.

B. Land which qualifies for rating 80 through 100 in the Storie Index Rating.

C. Land which supports livestock used for the production of food and fiber and which has an annual carrying capacity equivalent to at least one animal unit per acre as defined by the U.S.D.A.

D. Land planted with fruit or nut bearing trees, vines, bushes or crops which have a non- bearing period of less than five years and which would normally return during the commercial bearing period on an annual basis from the production of unprocessed agricultural plant production not less than $200.00 per acre. Humboldt County General Plan Adopted October 23, 2017 Part 2, Chapter 4. Land Use Element 4-32
E. Land which has returned from the production of unprocessed agricultural plant products on an annual gross value of not less than $200.00 per acre for three of the five previous years.

Prime agricultural soils are located west in some portions of the project areas near the percolation field (Humboldt County 2019, see Figure 3). Approximately 510 feet of the access road extension (shown as “new road” in Figure 3) would overlap with prime agricultural soils and convert approximately 7,650 square feet (< 0.2 acres) of pasture into an unpaved roadway. The existing farm road, approximately 2,530 feet in length, is also located on prime agricultural soils. The existing farm road spans two privately owned parcels, both zoned AE: APN 106-091-008-000 and 106-091-009-000 and totaling 329.99 acres. The access road extension is equivalent to 0.05% of the total area of the two combined parcels. The existing farm road is presently used to support Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-7 agricultural uses of the property. The footprint of the road extension is relatively small and would also support agricultural uses of the property, consistent with the use of the existing longer farm road (Figure 2). Because agriculture use of the property would continue undiminished and unimpeded and would benefit from the extended access road, the associated impact to prime agricultural soils would be less than significant.

The project is consistent with Section 3.34 (f) of the Eel River Local Coastal Plan, as the proposed access road extension would not interfere with the viability of surrounding agricultural uses and would instead enhance the viability of agricultural uses. Furthermore, under Humboldt County General Plan Policy AG-P6, the extension of the existing farm road to provide site access to the percolation field is consistent with an overriding public interest in development of a treated effluent disposal site (percolation field) for the public of the City of Fortuna, maintaining an essential public utility service. The project is further in the public interest in that it helps to ensure that water quality in the Eel River would be unimpacted by existing disposal methods via the percolation ponds currently in service at the WWTP.

A portion of the pipe staging area (approximately 2,370 linear feet) would overlap prime agriculture soils in the pasture. This area would be used solely to layout and feed the pipe into the directionally drilled inlet under the Eel River. Any impact would be temporary. Soil and vegetation disturbance is expected to be minimal. If vegetation is removed, the area would be reseeded with appropriate pasture species in coordination with the landowner. The impact associated with the temporary pipe staging to prime agricultural soils would be less than significant. b) Conflict with Agricultural Zoning or Williamson Act Contract? (Less than Significant Impact)
The project would not be located on lands under a Williamson Act contract (Humboldt County 2019). The WWTP is zoned Public Facilities (PF), which does not include zoning for agricultural or use. All project areas outside of the WWTP include AE zoning but are not enrolled in the Williamson Act (Humboldt County 2019). The two-acre planned percolation field area is not presently used for agricultural uses. Current use supports off-road vehicle recreation. Because the percolation infrastructure would be underground, future agricultural use of the facility would not be precluded. Therefore, the project would not conflict with the agricultural zoning. The potential impact would be less than significant.
c, d) Conflict with Forest Land Zoning or Convert Forest Land? (No Impact) There are no forest lands, timberland or timberland zoned Timberland Production in the project area; therefore, no forest land or timberland would be converted to non-forest or non-timberland use. No impact would result.
e) Convert Farmland or Forest? (Less than Significant Impact) The potential contingency directionally drilled mid-point inlet/outlet located on the Eel River floodplain is also zoned AE with a NR combining overlay, reflective of Eel River channel migration through time. This potential drilling location is near the low water margin of the Eel River and comprised entirely of floodplain (non-agrarian) habitat. Activity in this area would be temporary and farmland and/or natural resource uses would not be converted to any other conflicting use. There are no other changes in the existing environment related to the project that would impact Farmland or forest land in or adjacent to the study area. The potential impact will be less than significant.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-8 Air Quality
Potentially
Significant
Impact
Less-ThanSignificant With
Mitigation
Incorporation
Less-ThanSignificant
Impact
No
Impact
Where available, the
significance criteria established
by the applicable air quality
management district or air
pollution control district may be
relied upon to make the
following determinations. Would
the project:
a) Conflict with or obstruct
implementation of the
applicable air quality plan?

b) Result in a cumulatively
considerable net increase
in any criteria pollutant for
which the project region is
non-attainment under an
applicable federal or state
ambient air quality
standard?

c) Expose sensitive receptors
to substantial pollutant
concentrations?

d) Result in other emissions
(such as those leading to
odors) adversely affecting
a substantial number of
people?

The project is located within the North Coast Air Basin (Air Basin) which is managed by the North Coast Unified Air Quality Management District (NCUAQMD). The NCUAQMD monitors air quality; enforces local, State, and federal air quality regulations for counties within its jurisdiction; inventories and assesses the health risks of Toxic Air Contaminants (TACs); and adopts rules that limit pollution.

For construction emissions, the NCUAQMD has indicated that emissions are not considered regionally significant for projects whose construction would be relatively short in duration, lasting less than one year. For project construction lasting more than one year or that involves above average construction intensity in volume of equipment or area disturbed, construction emissions may be compared to the stationary source thresholds (NCUAQMD 2019). Construction is anticipated to last for approximately eight months. Although construction is anticipated to last less than one year, as a conservative approach to the analysis, emissions related to construction were calculated using the California Emissions Estimator Model (CalEEMod) version 2016.3.2 and are disclosed below. See Appendix A – Air Quality Modeling Results. a) Conflict with or obstruct implementation of the applicable air quality plan? (Less than Significant with Mitigation)
The U.S. Environmental Protection Agency (EPA) sets the National Ambient Air Quality Standards Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-9 for the following six criteria air pollutants: ozone, particulate matter (PM10 and PM2.5), nitrogen dioxide, carbon monoxide, lead, and sulfur dioxide. The California Air Resources Board (CARB) administers the California Ambient Air Quality Standards, which include the six criteria pollutants listed above as well as visibility-reducing particulates, hydrogen sulfide, sulfates, and vinyl chloride.

The NCUAQMD is listed as "attainment" or "unclassified" for all the federal and state ambient air quality standards with the exception of the state 24-hour particulate (PM10) standard in Humboldt County only. Primary sources of particulate matter in Humboldt County are on-road vehicles (engine exhaust and dust from paved and unpaved roads), open burning of vegetation (both residential and commercial), residential wood stoves, and stationary industrial sources (factories).

For the project, PM10 is of concern during construction because of the potential to emit fugitive dust during earth-disturbing activities. Operation of the project would not contribute PM10 of note. To address non-attainment for PM10, the NCUAQMD adopted a Particulate Matter Attainment Plan in 1995. This plan presents available information about the nature and causes of PM10 standard exceedances and identifies cost-effective control measures to reduce PM10 emissions to levels necessary to meet California Ambient Air Quality Standards. The control strategies relate to transportation control, land use, and open burning measures. The strategies are either implemented at the State or Air District level, or apply to land use projects. The project would not obstruct implementation of this plan. In addition, the NCUAQMD states that the plan, “should be used cautiously as it is not a document that is required in order for the District to come into attainment for the state standard” (NCUAQMD 2018).

Construction activities in the project area are subject to the NCUAQMD’s Rule 104 (Prohibitions) Section D (Fugitive Dust Emissions). Pursuant to Section D, the handling, transporting, or open storage of materials in such a manner, which allows or may allow unnecessary amounts of particulate matter to become airborne, shall not be permitted. Reasonable precautions shall be taken to prevent particulate matter from becoming airborne, including, but not limited to: 1) covering open bodied trucks when used for transporting materials likely to give rise to airborne dust; and 2) the use of water during the grading of roads or the clearing of land.

Improvement of the western access road as well as the new percolation field may result in fugitive dust emissions, which, if not handled correctly, could violate Rule 104. The impact to PM10 from project construction activities would therefore result in a significant impact.

Implementation of Mitigation Measure AIR-1 enhances compliance with Rule 104 by incorporating qualitative best management practices during construction. With implementation of Mitigation Measure AIR-1, the project would comply with applicable rules, and would not conflict with or obstruct implementation of the applicable air quality plan.

Mitigation
Mitigation Measure AIR-1: Dust Control
The City, at all times during construction, shall comply with Air Quality Regulation 1, Rule 104 (D) to the satisfaction of the NCUAQMD. This would require, but may not be limited to:
 Water all active construction areas regularly to limit dust; control erosion and prevent water runoff containing silt and debris from entering the storm drain system;  Cover trucks hauling soil, sand, and other loose material;  Pave, water, or apply non-toxic soil stabilizers on unpaved access roads and parking areas; and
Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-10  Sweep paved streets, access roads and parking areas daily if visible material is carried onto adjacent public streets.

Implementation of the following Mitigation Measure AIR-1 would reduce the impacts related to fugitive dust to less-than-significant.
b) Result in a cumulatively considerable net increase in any criteria pollutant for which the project region is non-attainment under an applicable federal or state ambient air quality standard? (Less than Significant)
Construction activities would temporarily create emissions of equipment exhaust and other air contaminants during the eight-month construction period. As stated above, the NCUAQMD considers construction activities that last for less than one year to have a less-than-significant impact. Because construction would only last for eight months, the project’s impact from construction emissions would be less than significant.

For the purposes of disclosure, Table 3.3-1 summarizes construction-related emissions and compares them to the NCUAQMD’s stationary sources emission thresholds. Construction-related emissions were modeled to be well below NCUAQMD stationary source thresholds. The potential impact would be less than significant.

Table 3.3-1 Construction Regional Pollutant Emissions
Parameter Emissions (tons)
ROG NOX CO PM10
Project Construction 0.03 0.21 0.23 6.47
NCUAQMD Stationary Source Thresholds 40 40 100 15
c) Expose sensitive receptors to substantial pollutant concentrations? (Less than Significant)
Sensitive receptors include school-aged children (schools, daycare, playgrounds), the elderly (retirement community, nursing homes), the infirm (medical facilities and offices), and those who exercise outdoors regularly (public and private exercise facilities, parks). The nearest residence to the project site is approximately 1,600 feet to the east, across US Highway 101. Other potential sensitive receptors occurring near the project site include the Fortuna Middle School, approximately 2,000 feet to the north, and South Fortuna Elementary School, approximately 4,000 feet to the east.

Construction of the project would be short in duration and would vary in location, thus not resulting in concentrated pollutants in any one area. Because of the distance to potential sensitive receptors, limited construction period, and geographical distribution of construction activities, exposure of sensitive receptors to substantial pollutant concentrations would be less than significant. d) Result in other emissions (such as those leading to odors) adversely affecting a substantial number of people? (Less than Significant)
Minor odors from the use of equipment during construction activities would be intermittent and temporary and would dissipate rapidly from the source with an increase in distance. This impact would be less than significant.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-11 Biological Resources
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
a) Have a substantial adverse effect, either
directly or through habitat modifications,
on any species identified as a candidate,
sensitive, or special-status species in
local or regional plans, policies, or
regulations, or by the California
Department of Fish and Game or U.S.

Fish and Wildlife Service?

b) Have a substantial adverse effect on
any riparian habitat or other sensitive
natural community identified in local or
regional plans, policies, regulations or
by the California Department of Fish and
Game or US Fish and Wildlife Service?

c) Have a substantial adverse effect on
state or federally protected wetlands
(including, but not limited to, marsh,
vernal pool, coastal, etc.) through direct
removal, filling, hydrological interruption,
or other means?

d) Interfere substantially with the
movement of any native resident or
migratory fish or wildlife species or with
established native resident or migratory
wildlife corridors, or impede the use of
native wildlife nursery sites?

e) Conflict with any local policies or
ordinances protecting biological
resources, such as a tree preservation
policy or ordinance?

f) Conflict with the provisions of an
adopted Habitat Conservation Plan,
Natural Community Conservation Plan,
or other approved local, regional, or
state habitat conservation plan?

Analysis in this section is based on the project’s Biological Resources Report (GHD 2019a), included as Attachment B.
a) Have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special-status species in local or regional plans, policies, or regulations, or by the California Department of Fish and Game or U.S. Fish and Wildlife Service? (Less Than Significant with Mitigation) Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-12 Special-status Plant Species and Sensitive Natural Communities Special status plant species under State jurisdiction include those listed as endangered, threatened, or as candidate species by the California Department of Fish and Wildlife (CDFW) under the California Endangered Species Act (CESA). Plant species on CNPS California Rare Plant Ranking (CRPR) Lists 1A, 1B and 2A and 2B are considered eligible for state listing as endangered or threatened pursuant to the California Fish and Game Code and CDFW has oversite of these special status plant species as a trustee agency. As part of the CEQA process, such species should be considered as they meet the definition of Threatened or Endangered under Sections 2062 and 2067 of the California Fish and Game Code. There are occasions where CRPR List 3 or 4 species might be considered of special concern particularly for the type locality of a plant, for populations at the periphery of a species range, or in areas where the taxon is especially uncommon or has sustained heavy losses, or from populations exhibiting unusual morphology.

One sensitive natural community was identified within the project area. Black cottonwood (Populus trichocarpa) forest occurs within the proposed effluent disposal area, and borders the proposed effluent percolation field on the south and east sides. This community type also occurs within the proposed project location for the directional drilling inlet on the east side of the Eel River. Black cottonwood forest alliance has a state rank of S3 and is considered Sensitive by CDFW, and it is assumed that the areas mapped as black cottonwood forest alliance would be considered an Environmentally Sensitive Habitat Area under the Eel River Area Local Coastal Plan and the Coastal Act.

No seasonally appropriate surveys for special status plants have been performed within the project area. Based on database searches, historical records, and an overview of the primary literature, only two special status species have a moderate or high potential of occurring in the project area.

Wolf’s evening primrose (Oenothera wolfii) has a CRPR of 1B.1 and has a moderate likelihood of occurring within the project area. Maple leaved checkerbloom (Sidalcea malachroides) has a CRPR of 4.2 and also has moderate likelihood of occurring within the project area. Five additional special status species are thought to have a low likelihood of occurring within the project area (GHD 2019a). Given that required protocol plant surveys are still underway, and because of the proximity of the project area to known populations of special-status plants, the impact on special-status plants is considered potentially significant.

Mitigation
Mitigation Measure BIO-1 would reduce the potential impact of the project on special-status plants to a less-than-significant level by requiring pre-construction surveys and measures to avoid take of species and compensation for loss of any habitat.

Mitigation Measure BIO-1: Protect Special Status Plants Mitigation measures for special status plant species are addressed collectively for all species. Significant impacts to special-status plant species present or likely to be present onsite shall be minimized, avoided, and (if necessary) compensated by complying with the following:
• Pre-construction surveys: Seasonally appropriate pre-construction surveys for special status plant species shall occur prior to construction within the planned area of disturbance for the project, during the appropriate blooming time (spring or summer) for the target species. Survey methods shall comply with CDFW rare plant survey protocols, and shall be performed by a qualified field botanist. Surveys shall be modified to include detection of juvenile (pre-flowering) colonies of Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-13 perennial species when necessary. Any populations of special status plant species that are detected shall be mapped. Populations shall be flagged if avoidance is feasible and if populations are located adjacent to construction areas. • The locations of any special status plant populations to be avoided shall be clearly identified in the contract documents (plans and specifications). • If special status plant populations are detected where construction would have unavoidable impacts, a compensatory conservation plan shall be prepared and implemented in coordination with CDFW. Such plans may include salvage, propagation, on-site reintroduction in restored habitats, and monitoring.

With the implementation of Mitigation Measure BIO-1, potential impacts to special status plants would be less than significant.

Special-status Wildlife Species
The only special status wildlife species with the potential to occur in the project area is the North American Porcupine (Erethizon dorsatum), which is a State Special Status Species (GHD 2019a).

North American Porcupines are primarily nocturnal, but can sometimes be seen during the day.

They are approximately 27 inches in length with yellowish quills on the head, rump, and upper surfaces of the tail. Their range extends across mainland Canada, Alaska, and the western and northeastern United States. They use a wide variety of habitats, but are most common in montane conifer, Douglas fir, and alpine dwarf‐shrub. There are numerous occurrence records (both historical and recent) from the larger project vicinity, especially the Eel River estuary, and suitable habitat for the species is present on site (GHD 2019a). Although there are records of North American Porcupines from the general project vicinity and they have a moderate potential to occur onsite, no impacts are expected to occur to this species. The species is highly mobile and, if present, is expected to leave the project area once construction activity commences. Although some foraging habitat (riparian forest) would be removed in association with this project, substantial foraging habitat suitable for this species is present in the surrounding area (riparian forest along the Eel River). As no impacts to this species are expected, the potential impact would be less than significant.

Special-status Fish Species
Federally threatened salmonids (Coho Salmon (Oncorhynchus kisutch), federally threatened Northern California Steelhead (Oncorhynchus mykiss irideus), and Chinook Salmon (Oncorhynchus tshawytscha) are known to occur nearby in the Eel River and could potentially be impacted by project construction. Additional species which could be nearby and potentially impacted include Green Sturgeon (Acipenser medirostris), which is listed as federally threatened, Pacific Lamprey (Entosphenus tridentatus), which is a State Species of Special Concern, and Coastal Cutthroat Trout (Oncorhynchus clarkia clarkia), also a State Species of Special Concern. The Eel River is designated Critical Habitat for Coho Salmon, Northern California Steelhead, and Chinook Salmon.

Essential Fish Habitat also occurs in the Eel River between the two primary project areas.

Special-status fish species were evaluated in the Biological Resources Report (GHD 2019a). With the exception of Green Sturgeon, all other above-noted special status fish species have the potential to be present at or near the project site during construction. Due to the nature of the project, there is potential for adverse effects to these species and their habitats from construction activities occurring adjacent to the river (e.g. possibility for sediment discharge), and beneath the river (e.g. possibility for directional drilling to erroneously puncture the river bottom or cause a fracout). However, the project, at its closest location to the Eel River, is located approximately 100 feet Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-14 from the banks of the Eel River at the WWTP at the drill pit. The horizontal directional drilling would be completed by trained professionals at approximately 20 feet to 40 feet below the Eel River and 10 feet to 20 feet below Strongs Creek, which would not disturb in-stream habitat because no physical activity would take place within the river and stream channels. The potential impact on special-status fish species would be potentially significant.

Mitigation Measures HWQ-1 and HWQ-2 (see Section 3.10 (a)) would serve to protect water quality during construction and require development of a Frac-Out Contingency Plan. Mitigation Measure BIO-6 (see Section 3.4 (c) below) establishes avoidance and minimization measures to protect waters from sediment-related impacts. With the implementation of Mitigation Measures HWQ-1, HWQ-2, and BIO-6, the impact to special status fish would be less than significant.

Special-status Amphibian Species
Northern Red-legged Frogs (Rana aurora) are a State Species of Concern and occur along the west coast of North America from British Columbia to California and were evaluated in the Biological Resources Report (GHD 2019a). The geographic range split between the Northern and California Red-legged Frog species occurs just south of Elk Creek in Mendocino County where both species overlap. Northern Red-legged Frogs are typically found near freshwater sources (e.g., wetlands, ponds, streams, etc.). However, they can range widely and inhabit damp places far from water. Northern Red-legged Frogs reproduce in water from December to February in Humboldt County, with some breeding occurring as late as March. Preferred egg laying locations are in “vegetated shallows with little water flow in permanent wetlands and temporary pools.” Northern Red-legged Frogs are relatively common in and near coastal portions of Humboldt County and recent records have documented the species near the project area. This being the case, Northern Red-legged Frogs have a moderate chance of occurring within the project area. Northern Redlegged Frogs have also been documented at the WWTP on previous site visits. Therefore, the potential impact on Northern Red-legged frogs is considered significant.

Western Pond Turtles (pond turtles) (Emys marmorata) are a State Species of Concern and occur in a variety of permanent and semi-permanent freshwater aquatic habitats including lakes, rivers, ponds, creeks, and marshes and were also assessed in the Biological Resources Report (GHD 2019a). Pond turtles are known to be present in the general vicinity and may occur along the river bank not far from the project area. Breeding can occur on loose soils on south or west facing slopes so a few pond turtles may venture away from the river into the project area. The species is frequently observed basking on exposed banks, logs, and rocks. Winter activity is possible but limited to unusually warm, sunny days; normally pond turtles are dormant during winter months on the north coast; dormancy typically involves burrowing into loose substrate above the high water mark. Pond turtles have been documented nesting up to 0.5 kilometers from water. Thus, Western Pond Turtles have a moderate chance of occurring within the project area although presence would likely be occasional, seasonal, and temporary. The potential impact to individual Western Pond Turtle is considered significant.

Mitigation
Mitigation Measure BIO-2 would reduce the impact of the project on special status amphibians and reptiles to less-than-significant levels by requiring pre-construction surveys by qualified biologists prior to work in applicable habitats, and measures to avoid take of species.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-15 Mitigation Measure BIO-2: Protect Special Status Amphibians and Reptiles No more than one week prior to commencement of ground disturbance within 50 feet of suitable Northern Red-legged Frog or Western Pond Turtle habitat, a qualified biologist shall perform a pre-construction survey and shall relocate any individuals of Northern Redlegged Frog or Western Pond Turtle or egg masses of Northern Red-legged Frog that occur within the work -impact zone to nearby suitable habitat.

In the event that a Northern Red-legged Frog or Western Pond Turtle is observed in an active construction zone, the contractor shall halt construction activities in the area where observed and the frogs or turtles shall be moved to a safe location in similar habitat outside of the construction zone. The same measures above shall apply to Foothill Yellow-legged Frogs which are State Species of Concern and are no longer a CESA candidate.

With the implementation of Mitigation Measure BIO-2, potential impacts to special status amphibians and reptiles will be less than significant.

Passerines and Raptors
In support of the Biological Resources Report (GHD 2019a), reconnaissance-level bird surveys occurred at the project area. During this survey, special-status species observed included Cooper’s Hawk (Accipiter cooperi), Sharp-shinned Hawk (Accipiter striatus), Great Egret (Ardea alba), Whitetailed Kite (Elanus leucurus), and American Peregrine Falcon (Falco peregrinus anatum). Additional special status species were documented as having potential to occur at the project area, including Snowy Egret (Egretta thula), Black-crowned Night Heron (Nycticorax nycticorax), and Osprey (Pandion haliaetus). In addition, native migratory birds may also be present at the project area. If nesting passerines or raptors were present in trees in the project area, construction noise and/or tree removals would have the potential to impact the species. The impact is considered significant.

Mitigation
Mitigation Measure BIO-3 would reduce the impact of the project on nesting passerines or raptors to less-than-significant levels by requiring pre-construction surveys by qualified biologists prior to work in applicable habitats, and measures to avoid take of species.

Mitigation Measure BIO-3: Protect Special Status, Migratory, and Nesting Birds
Ground disturbance and vegetation clearing shall be conducted, if possible, during the fall and/or winter months and outside of the avian nesting season (March 15 – August 15) to avoid any direct effects to special status and protected birds. If ground disturbance cannot be confined to work outside of the nesting season, a qualified ornithologist shall conduct pre-construction surveys within the vicinity of the project area, to check for nesting activity of native birds and to evaluate the site for presence of raptors and special status bird species. The ornithologist shall conduct at minimum a one day pre-construction survey within the 7-day period prior to vegetation removal and ground-disturbing activities. If ground disturbance and vegetation removal work lapses for seven days or longer during the breeding season, a qualified ornithologist shall conduct a supplemental avian preconstruction survey before project work is reinitiated.

If active nests are detected within the construction footprint or within the construction buffer established by the project biologist, the biologist shall flag a buffer around each nest.

Construction activities shall avoid nest sites until the biologist determines that the young have fledged or nesting activity has ceased. If nests are documented outside of the Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-16 construction (disturbance) footprint, but within the construction buffer, nest buffers would be implemented as needed. In general, the buffer size for common species would be determined on a case-by-case basis in consultation with CDFW. Buffer sizes would take into account factors such as (1) noise and human disturbance levels at the construction site at the time of the survey and the noise and disturbance expected during the construction activity; (2) distance and amount of vegetation or other screening between the construction site and the nest; and (3) sensitivity of individual nesting species and behaviors of the nesting birds.

If active nests are detected during the survey, the qualified ornithologist shall monitor all nests at least once per week to determine whether birds are being disturbed. Activities that might, in the opinion of the qualified ornithologist, disturb nesting activities (e.g., excessive noise), shall be prohibited within the buffer zone until such a determination is made. If signs of disturbance or distress are observed, the qualified ornithologist shall immediately implement adaptive measures to reduce disturbance. These measures may include, but are not limited to, increasing buffer size, halting disruptive construction activities in the vicinity of the nest until fledging is confirmed or nesting activity has ceased, placement of visual screens or sound dampening structures between the nest and construction activity, reducing speed limits, replacing and updating noisy equipment, queuing trucks to distribute idling noise, locating vehicle access points and loading and shipping facilities away from noise-sensitive receptors, reducing the number of noisy construction activities occurring simultaneously, and/or reorienting and/or relocating construction equipment to minimize noise at noise-sensitive receptors.

With the implementation of Mitigation Measure BIO-3, potential impacts to special status, migratory, and nesting birds would be less than significant.

Bats
Several special status bat species have the potential to be present at or near the project area, including the Pallid Bat (Antrozous pallidus), Townsend’s Big-eared Bat (Corynorhinus townsendii), Hoary Bat (Lasiurus cinereus), and Yuma myotis (Myotis yumanensis).

Habitat for bats (tree cavities, loose bark, riparian forest, etc.) is present in the project area (based on reconnaissance level surveys). Vegetation and structures in the project area likely provide habitat to a variety of bat species. Construction of the project may adversely impact special-status bat species through the removal or modification of vegetation or structures and due to ground disturbance. The impact is considered significant. Mitigation Measure BIO-4 has been incorporated into the project to ensure potential impacts to special status bats would be less than significant.

Mitigation
Mitigation Measure BIO-4 would reduce the impact of the project on special status bats to lessthan-significant levels by requiring pre-construction surveys by qualified biologists prior to work in applicable habitats, and measures to avoid take of species.

Mitigation Measure BIO-4: Protect Special Status Bats
A qualified bat biologist shall conduct habitat surveys for special-status bats. Survey methodology should include visual examination of suitable habitat areas for signs of bat use and may utilize ultrasonic detectors to determine if special status bat species utilize the vicinity. Trees within 300 feet of construction activities should be examined. If habitat exists, species presence and site use patterns should be documented, including roost Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-17 sites. Bat presence in the project may vary seasonally and annually. Surveys should be conducted in a manner to detect the presence of hibernating or torpid bats, reproductive colonies and/or migratory stop‐over roosts. If no bat utilization or roosts are found, then no further study or action is required. If bats are found to utilize the project vicinity, or presence is assumed, a bat specialist should be engaged to advise the best method to prevent impact. This may include, but would not be limited to:
 Consultation with the California Department of Fish and Wildlife to determine appropriate measures for protecting bats with young if present, and for implementing measures to exclude non-breeding bat colonies during construction process.  Phased removal of trees where selected limbs and branches not containing cavities are removed on the first day, with the remainder of the tree removed on the second day.

The implementation of Mitigation Measures BIO-4 would protect against potential project impacts to special status bats, sufficiently reducing the potential effect to be less than significant. b,c) Have a substantial adverse effect on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, regulations or by the California Department of Fish and Game or US Fish and Wildlife Service, including wetlands? (Less Than Significant with Mitigation)
Mapping of sensitive natural communities occurred on November 6 and November 12, 2019.

Components of the project were visited and surveyed for vegetation communities; additional developed project components (e.g. existing stockpile areas near the WWTP) were analyzed via aerial imagery (GHD 2019a). One sensitive natural community was identified within the project area. Black cottonwood (Populus trichocarpa) forest occurs within the percolation field area. The black cottonwood community borders the percolation field area on the south and east sides. The riparian vegetation occurring within the proposed project location for the drill pit on the east side of the Eel River, at the existing WWTP, was also identified and mapped as black cottonwood forest.

Black cottonwood forest alliance has a state ranking of S3 and is considered Sensitive by CDFW.

The vegetation mapped as black cottonwood forest alliance is riparian vegetation which would also be regulated by the California Department of Fish and Wildlife through the Lake and Streambed Alteration permit process (California Department of Fish and Game Code Section 1602).

As no impacts to the riparian forest surrounding the future percolation field are anticipated, alliance level mapping was not performed for these specific riparian areas. However, black cottonwood was observed in the overstory canopy of the adjacent riparian forest adjacent to both the access route and also adjacent to the potential staging area for the pipe and it is likely this forest would also fit the black cottonwood forest alliance.

Actual limits of construction have yet to be finalized. Mapped sensitive natural communities would be avoided to the greatest extent practicable; however, the project may potentially require vegetation and tree removal that would impact the black cottonwood habitat. Therefore, the impact on black cottonwood forest is considered potentially significant.

The project may also potentially require temporary disturbance and/or permanent fill of seasonal wetlands within the construction area. Potential impacts to seasonal wetland and other jurisdictional waters would be significant.

Mitigation
Mitigation Measures BIO-5 through BIO-7 require avoidance and minimization of permanent Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-18 impacts and temporary impacts to sensitive natural communities and wetlands during construction, restoration of pre-project conditions at the conclusion of construction, and compensation of regulated wetlands and sensitive natural communities, thereby reducing potential impacts to natural communities and wetlands to a less-than-significant level.

Mitigation Measure BIO-5: Compensatory Mitigation for Sensitive Natural Communities
Construction within mapped sensitive natural communities (black cottonwood) shall be avoided to the greatest extent practicable. If impacts are unavoidable and black cottonwood trees mapped as ESHA are removed or detrimentally impacted, mitigation would occur. A Mitigation and Monitoring Plan shall be prepared in coordination with State resource agencies.

The Plan shall be acceptable to State agencies with jurisdiction and include the following elements: proposed mitigation ratios; description and size of the restoration or compensatory area; site preparation and design; plant species; planting design and techniques; maintenance activities; plant storage; irrigation requirements; success criteria; monitoring schedule; and remedial measures. The ratio and conditions of mitigation would be negotiated in consultation with the City and State resource agencies with jurisdiction over sensitive natural communities. The Plan shall be implemented by the City.

Mitigation Measure BIO-6: Avoidance and Minimization Measures to Protect Juxtaposed Wetlands
One – and three-parameter wetland delineation will occur within the project footprint and will include identification of adjacent wetlands (juxtaposed). The City shall implement the following avoidance and protection measures for juxtaposed Waters of the United States and Waters of the State that would not be impacted (filled or excavated) during project construction:

1. The City shall attempt to avoid or minimize impacts to wetlands/waters to the greatest extent feasible in the final design plans.

2. Juxtaposed wetlands shall be clearly identified in the construction documents and reviewed by the City prior to issuing for bid to ensure they are clearly marked as equipment exclusion zones during construction.

3. Suitable perimeter control BMPs, such as silt fences, or straw wattles shall be placed below all construction activities at the edge of surface water features to intercept sediment before it reaches the waterway. These BMPs shall be installed prior to any clearing or grading activities.

Mitigation Measure BIO-7: Compensate for Loss of Wetlands and Waters One – and three-parameter wetland delineation will occur within the project footprint. The City shall conduct a seasonally appropriate pre-construction wetland delineation in areas to be impacted by project construction that may include wetlands (both temporary and permanent impacts). The City shall avoid fill of seasonal wetlands and waters, to the extent feasible. If fill cannot be avoided, the City shall compensate for the loss of seasonal wetland habitat so that there is no net loss in wetlands. The City shall compensate for impacts to identified wetlands through restoration, rehabilitation, and/or creation of wetland at a ratio Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-19 of no less than 1:1. A Mitigation and Monitoring Plan shall be prepared in coordination with the NCRWQB, the USACE and the CCC. Compensation for wetlands shall occur so there is no net loss of wetland habitat at ratios to be determined in consultation with the NCRWQCB. The Plan shall be acceptable to the regulatory agencies with jurisdiction over wetlands and waters and include the following elements: proposed mitigation ratios; description and size of the restoration or compensatory area; site preparation and design; plant species; planting design and techniques; maintenance activities; plant storage; irrigation requirements; success criteria; monitoring schedule; and remedial measures. The Plan shall be implemented by the City.

The City shall also compensate for impacts to other waters by obtaining required permits from the U.S. Army Corp of Engineers, the North Coast Regional Water Quality Control Board, and the California Department of Fish and Game shall be received prior to the start of any on-site construction activity. The City shall ensure any additional measures outlined in the permits are implemented.

Implementation of Mitigation Measures BIO-5 through BIO-7 will reduce potential impacts to wetlands to a less-than-significant level.
d) Interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites? (Less Than Significant with Mitigation)
Project construction and operations do not include in-water work or any other activity that might impede fish migration. Terrestrial project construction and operations do not include construction of any barriers to wildlife migration (e.g. fencing, highly developed roadway, or large structures).

Deterrence of migratory and nesting birds associated with noise is addressed in Section 3.4 (a) with Mitigation Measure BIO-3 to ensure the potential impact to migratory and nesting birds would be less than significant.
e) Conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance? (Less Than Significant) Tree removal may occur to support construction of the two-acre percolation field, which is in the jurisdiction of Humboldt County. Utilization of drill pit Contingency B may also necessitate tree removal and is located within the jurisdiction of the City.

City of Fortuna
The WWTP and other eastern project areas are within the jurisdiction of the City of Fortuna. The City of Fortuna General Plan’s Resource Management and Conservation Element establishes policies to protect biological resources within City limits including protected streams and wetlands (City of Fortuna 2010). Applicable policies include:
• NCR-2.1 Riparian Corridor Protection
• NCR-2.10 Wetland Identification and Protection
• NCR-2.12 Permitted Activities with ESHAs
• NC-2.13 Watercourse, Wetland and Riparian Buffers
Section 17.06.171 (B) (Removal of natural materials) of the City’s Zoning Code address tree removal and states that the removal of trees shall occur in accordance with applicable sections of the California Forest Practices Act. If the Forest Practices Act is applicable, a Use Permit must be Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-20 obtained from the planning commission prior to any removal of trees. The project area does not include forest resources; thus the Forest Practices Act is not applicable.

Eel River Area Local Coastal Plan
The Eel River Area Local Coastal Plan (Humboldt County 2014) identifies land uses and standards by which development would be evaluated within the Coastal Zone. Applicable policies include:
• 3.41: Protection of Environmentally Sensitive Habitat Areas o 3.41 B: Wetland Identification and Development Policies o 3.41 F-4: Development and Uses within the Riparian Corridor o 3.41 F-5: Development and Uses within the Riparian Forest (located outside of the riparian corridor)
o 3.41 F-6: Other Riparian Protection Measures
Humboldt County
The Open Space and Conservation Element of the Humboldt County General Plan (2017) summarizes policies germane to the protection of biological resources. Applicable policies include:
• BR-P1: Wetland Identification,
• BR-S10: Development Standards for Wetlands, and
• BR-S11: Wetlands Defined.

Policy BR-S10 established that development standards for wetlands shall be consistent with the standards for Streamside Management Areas (SMA). The SMA width applied to wetlands is designated as 50 feet for seasonal wetlands and 150 feet for perennial wetlands. The setback begins at the edge of the delineated wetland.

Humboldt County does regulate tree removal for trees larger than 12 inches in diameter that are in residential zones through a Special Permit. As all potential tree removal associated with the project would occur outside a residential zone, Humboldt County’s tree removal policy does not apply.

As the project would obtain a Use Permit from Humboldt County for construction and operations to occur in eastern project areas, the project would be required to be consistent with all applicable provisions of both the Eel River Area Local Coastal Plan and the Humboldt County General Plan as a condition of the permit.

The project would obtain any necessary resource agency permits and would avoid and/or compensate for any impacts to wetlands and waters to ensure that no net loss occurs, ensuring adherence to City of Fortuna policies NCR-2.1, NCR-2.10, NCR-2.12, and NCR-2.13. No conflicts with policies or ordinances protecting biological resources have been identified. Therefore, the impact would be less than significant.
f) Conflict with the provisions of an adopted Habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan? (No Impact)
There are no adopted Habitat Conservation, Community Conservation, or approval local, regional, or state habitat conservation plans that apply to the project area. No impact would result.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-21 Cultural Resources
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
a) Cause a substantial adverse change in
the significance of a historical resource
pursuant to §15064.5?

b) Cause a substantial adverse change in
the significance of an archaeological
resource pursuant to §15064.5?

c) Disturb any human remains, including
those interred outside of formal
cemeteries?

a-c) Cause a substantial adverse change in the significance of a historical resource pursuant to §15064.5? Cause a substantial adverse change in the significance of an archaeological resource pursuant to §15064.5? Disturb any human remains, including those interred outside of formal cemeteries? (Less Than Significant with Mitigation Incorporated)
An archeological survey and Historic Property Identification Report (HPIR) was completed during December 2019 and provided to the City. (DZC 2019). As part of the HPIR, project notification letters, separate from AB 52 notification letters, were sent to area tribes on December 4, 2019.

Follow up correspondence between the cultural resource investigator DZC Archaeology & Cultural Resource Management and tribal representatives directly informed mitigation measures included below (DZC 2019).

One previously recorded historical resource, as defined in § 15064.5, is reported as located within or immediately adjacent to the project APE. The historical resource is the ethnographic Wiyot village of kwigërgoyok. This resource is eligible for listing on the California Register of Historic Resources (DZC 2019). Although the area is subject to periodic river flooding and surficial remains of the resource were not located, there is a potential for discovery of the site during project activities and a subsequent potential to cause a substantial adverse change in the significance of a historical resource pursuant to § 15064.5. The impact is considered significant.

In conjunction with the archeological survey and report, the local Tribal Historic Preservation Officers (THPOs) and NAHC were consulted. No Sacred Lands were identified within the APE, and no human remains are known to exist within the project site. However, there is potential for earthwork and grading to result in the disturbance of previously undiscovered archaeological resources or previously unrecorded human remains, if present. Therefore, the impact is considered potentially significant.

No other listed historical resources are present within the project area, and the existing WWTP would not meet any of the context types required for establishment of historic significance.

Mitigation
Implementation of Mitigation Measures CUL-1 and CUL-2 would reduce the potential impact to archaeological resources or human remains by requiring construction worker training, construction monitoring, and procedures that shall be taken in the event of inadvertent discovery.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-22 Mitigation Measure (CUL-1): Protect Archaeological or Tribal Cultural Resources during Construction
Prior to the ground-disturbing construction activities (on the first day of work), construction personnel shall receive Cultural Resources Awareness Training to ensure that construction activities are conducted in a manner that is protective of known and unknown cultural resources. The training shall include information on the location and lateral extent of potential nearby cultural resources sites, avoidance of those areas, laws protecting such resources, and procedures for responding to inadvertent discovery situations. Avoidance of known cultural resources sites shall be determined by a professional archaeologist or Native American monitor and include establishing a nodisturbance buffer zone around known resources.

Initial ground-disturbing activities near the previously recorded on-site historical resource shall be monitored by a professional archaeologist. If archaeological remains or potential tribal cultural resources are encountered during initial-ground disturbing activities, all work shall halt within a 50-foot radius of a discovery. Construction personnel shall not collect cultural materials. A qualified professional archaeologist shall be retained to evaluate the find, and the appropriate tribal representative(s) shall be notified. If the find qualifies as a historical resource or unique archaeological resource as defined by CEQA, the archaeologist shall develop appropriate measures to protect the integrity of the resource and ensure that no additional resources are affected. If the find qualifies as a tribal cultural resource as defined by CEQA, the City shall ensure that appropriate actions to protect the resource are taken and that no additional resources are affected.

Mitigation Measure (CUL-2): Minimize Impacts to Unknown Archaeological Resources or Human Remains if Encountered
In the event that any subsurface archaeological features or deposits, including locally darkened midden soil, are discovered during construction-related earth-moving activities, all ground-disturbing activity in the vicinity of the resource shall be halted, a qualified professional archaeologist shall be retained to evaluate the find, and the appropriate tribal representative(s) shall be notified. If the find qualifies as a historical resource or unique archaeological resource as defined by CEQA, the archaeologist shall develop appropriate measures to protect the integrity of the resource and ensure that no additional resources are affected.

If human remains, associated grave goods, or items of cultural patrimony are encountered during construction, work shall halt in the vicinity of the find and the County Coroner shall be notified immediately. The following procedures shall be followed as required by Public Resources Code § 5097.9 and Health and Safety Code § 7050.5. If the human remains are determined to be of Native American origin, the Coroner shall notify the Native American Heritage Commission within 24 hours of the determination.

The Native American Heritage Commission shall then notify the Most Likely Descendant (MLD), who has 48 hours to make recommendations to the landowner for the disposition of the remains. A qualified archaeologist, the City and the MLD shall make all reasonable efforts to develop an agreement for the treatment, with appropriate dignity, of any human remains and associated or unassociated funerary objects. The agreement would take into consideration the appropriate excavation, removal, recordation, analysis, custodianship, and final disposition of the human remains and associated or unassociated funerary Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-23 objects.

Implementation of Mitigation Measures CUL-1 and CUL-2 would reduce potential impacts related to inadvertent discovery of cultural resources to be less than significant.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-24 Energy
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
a) Result in potentially significant
environmental impacts due to
wasteful, inefficient, or unnecessary
consumption of energy resources,
during project construction or
operation?

b) Conflict with or obstruct a state or
local plan for renewable energy or
energy efficiency?

a) Result in potentially significant environmental impacts due to wasteful, inefficient, or unnecessary consumption of energy resources, during project construction or operation? (Less than Significant)
Temporary energy use in connection with project construction would entail consumption of diesel fuel and gasoline by construction equipment and by the transportation of earth moving equipment, construction materials, supplies, and construction personnel. Given the short construction period and implementation of State regulations regarding vehicle emission and fuels standards, such as the Low Carbon Fuel Standard and anti-idling regulations, energy use related to construction would not be wasteful or inefficient.

Operationally, pumping would be required to convey treated effluent from the WWTP to the subsurface percolation field area generally from May 15 through September 30. Pumping energy demands would be approximately 185,000 kWh per year. The pumps would be high efficiency variable speed pumps, with the pump output adjusted to meet the system requirements. The pump would only be in use when needed; thus no energy would be wasted running the pumps when not needed. The pumps have a design point overall efficiency of approximately 77%. In addition, certain existing WWTP facilities would be taken off-line when the new pump station is used resulting in nominal reduction in energy use for these related facilities. There also would be a small amount of fuel used for maintenance worker trips to the percolation field site. Neither the pumping nor the worker trips would be conducted in a manner that would result in wasteful, inefficient, or unnecessary consumption of energy. Impacts related to energy use during construction and operation of the project would therefore be less than significant. b) Conflict with or obstruct a state or local plan for renewable energy or energy efficiency? (No Impact)
State of California Energy Action Plan
In 2003, the three key energy agencies in California— the California Energy Commission (CEC), the California Power Authority (CPA), and the California Public Utilities Commission (CPUC)— jointly adopted an Energy Action Plan (EAP) that listed goals for California’s energy future and set forth a commitment to achieve these goals through specific actions. In 2005, the CPUC and the CEC jointly prepared the EAP II to identify the further actions necessary to meet California’s future energy needs. To the extent that efficiency, demand response, renewable resources, and distributed generation are unable to satisfy increasing energy and capacity needs, the EAP II Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-25 supports the use of clean and efficient fossil-fired generation. The plan recognizes that concurrent improvements are required to the bulk electricity transmission grid and distribution facility infrastructure to support growing demand centers and the interconnection of new generation, both on the utility and customer side of the meter.

Senate Bill 1389
Senate Bill (SB) 1389, the California Integrated Energy Policy, was adopted in August 2002 and requires the CEC to prepare an Integrated Energy Policy Report (IEPR) for electricity, natural gas, and transportation fuels. The IEPR contains an analysis of the policies and actions that are necessary to ensure that the state has adequate energy resources—including a range of alternative energy resources—to meet its needs. The IEPR also includes recommendations to reduce energy demand and to improve the state‘s energy infrastructure.

City of Fortuna
There are no applicable renewable energy or energy efficiency plans in the City of Fortuna related to infrastructure projects.

Eel River Area Local Coastal Plan
The Eel River Local Coastal Plan does not include applicable policies related to renewable energy or energy efficiency plans.

Humboldt County
The Humboldt County General Plan (Humboldt County 2017) Energy Element includes policies to address energy needs, use, and conservation. The policies do not include anything applicable to the percolation field site and related project areas west of the Eel River.

These plans contain broad policy and regulatory initiatives, which are not always applicable at the project level, particularly with infrastructure projects. They require action at the State and County level. Implementation of the project would not conflict with or obstruct the implementation of any of the policies and actions described above. The project would not conflict with or obstruct a State or local plan for renewable energy or energy efficiency. There would be no impact.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-26 Geology and Soils
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
a) Directly or indirectly cause potential
substantial adverse effects, including
the risk of loss, injury, or death
involving:
i) Rupture of a known earthquake
fault, as delineated on the most
recent Alquist-Priolo Earthquake
Fault Zoning Map issued by the
State Geologist for the area or
based on other substantial
evidence of a known fault? Refer
to Division of Mines and Geology
Special Publication 42?

ii) Strong seismic ground shaking? 
iii) Seismic related ground failure,
including liquefaction?

iv) Landslides? 
a) Result in substantial soil erosion or the
loss of topsoil? 
b) Be located on a geologic unit or soil that
is unstable, or that would become
unstable as a result of the project, and
potentially result in on, or off, site
landslide, lateral spreading, subsidence,
liquefaction or collapse?

c) Be located on expansive soil, as defined
in Table 18-1-B of the Uniform Building
Code (1994), creating substantial direct
or indirect risks to life or property?

d) Have soils incapable of adequately
supporting the use of septic tanks or
alternative wastewater disposal systems
where sewers are not available for the
disposal of wastewater?

e) Directly or indirectly destroy a unique
paleontological resource or site or
unique geologic feature?

The project is located on generally flat and gently sloping Eel River valley. Soils at the WWTP have been previously disturbed and compacted during initial WWTP construction and subsequent improvements. Soils in project areas west of the Eel River have experienced less disturbance and development.

The overall site for the new percolation field is comprised of 60 acres that are generally located along the Eel River. Soils within the proposed site are primarily classified as Water and Fluvents, which is reflective of the historical movement of the Eel River in the area. Slopes range from 0 to 2 Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-27 percent. The western and southern portions of the site are classified as Udifluvents a, i) Rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other substantial evidence of a known fault? Refer to Division of Mines and Geology Special Publication 42. (No Impact)
The project site is not located within an active Alquist-Priolo fault mapped by the California Geological Survey (DOC 2019b). The project would have no impact with regard to the rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map. The nearest fault zone is the Hydesville Fault Zone, including the Little Salmon fault, approximately 2 miles east of the project (DOC 2019b). Additionally, the project does not include structures designed for human occupancy. No impact related to fault rupture would result. a, ii) Strong seismic ground shaking? (Less Than Significant) The project is situated within a seismically active area close to several seismic sources capable of generating moderate to strong ground motions. Because the project is located within a seismically active area, the probability that strong ground shaking associated with large magnitude earthquakes would occur during the design life of the underground pipeline is high. Thus, the pipeline would be designed to resist moderate to very strong levels of seismic ground shaking without experiencing structure damage, consistent with recommendation from the geotechnical investigation (see Environmental Protection Action 1).

Project implementation would not increase risk of strong seismic ground shaking or exposure to strong seismic ground shaking above existing conditions. If strong seismic ground shaking were to damage the proposed facilities, it is unlikely that human lives would be put at risk because the project does not involve the construction of habitable structures. The project would be constructed to the seismic standards of the most recent California Building Code, as applicable. Therefore, the impact to people and structures from strong seismic ground shaking would be less than significant. a.iii, a.iv, c) Liquefaction, landslides, or otherwise unstable soils? (No Impact) The project is located in a mapped liquefaction hazard zone (Humboldt PBD 2015). Liquefaction is a phenomenon involving loss of soil strength, and resulting in fluid mobility through the soil.

Liquefaction typically occurs when loose, uniformly-sized, saturated sands or silts are subjected to repeated shaking in areas where the groundwater is less than 50 feet below ground surface. In addition to the necessary soil and groundwater conditions, the ground acceleration must be high enough, and the duration of the shaking must be sufficient, for liquefaction to occur.

The potential for liquefaction-related settlement exists at the project site. Earthquake-related liquefaction could result in sand boils and minor differential settlement on the site; however, lateral spreading due to liquefaction is not anticipated to affect the project site given that there are no free facies of significance nearby. Project implementation would not increase risk of liquefaction or exposure to liquefaction above existing conditions and no impact would occur.

The project area is generally flat and gently sloping, located in the Eel River valley. Steep slopes and hillslopes are not present within the project area. Thus, landslides within or near the project are unlikely to occur, and the potential for landslide occurrence is not increased by the project.

In addition, the City shall implement Environmental Protection Action 1 – Implement Geotechnical Design Recommendations, which would further address the seismic and foundation design criteria and determine the appropriate method of directional drilling under the Eel River. No impact would result.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-28 b) Result in substantial soil erosion or the loss of topsoil? (Less Than Significant Impact)
Construction activities, including cut, fill, removal of vegetation, directional drilling, and operation of heavy machinery will disturb soil and, therefore, have the potential to cause erosion. Erosion and sediment control provisions prescribed in the Fortuna Municipal Code, Humboldt County Code, NCRWQCB regulations, and the California Building Code (CBC) would be required as part of the project. BMPs may include: silt fences, straw wattles, soil stabilization controls, site watering for controlling dust, and sediment detention basins. Environmental Protection Action 2 requires development and implementation of a SWPPP in accordance with the State General Construction Permit. These mandatory ordinance requirements and permits are designed to maintain potential water quality impacts at a less than significant level during and post construction. Therefore, the potential soil erosion impact would be less than significant. d) Have soils incapable of adequately supporting the use of septic tanks or alternative wastewater disposal systems where sewers are not available for the disposal of wastewater? (No Impact)
The purpose of the project is to develop an alternative wastewater disposal system for the City. The percolation field was identified during feasibility investigations as a desirable location for effluent disposal based on the presence of soils suitable for infiltration and soil digestion of wastewater (GHD 2019b). The project does not include the use of septic tanks or other alternative wastewater disposal systems. No impact would result.
e) Directly or indirectly destroy a unique paleontological resource or site or unique geologic feature? (Less Than Significant with Mitigation) Paleontological resources are the remains or traces of prehistoric animals and plants. Paleontological resources, which include fossil remains and geologic sites with fossil-bearing strata are nonrenewable and scarce and are a sensitive resource afforded protection under environmental legislation in California. Under California PRC § 5097.5, unauthorized disturbance or removal of a fossil locality or remains on public land is a misdemeanor. State law also requires reasonable mitigation of adverse environmental impacts that result from development of public land and affect paleontological resources (PRC § 30244).

It is unlikely that project construction will impact potentially significant paleontological resources because most of the project occurs in relatively newly deposited alluvium. However, the possibility of encountering a paleontological resource during construction cannot be completely discounted, therefore, the impact related to the potential disturbance or damage of previously undiscovered paleontological resources, if present, is considered potentially significant.

Mitigation
Mitigation Measure GEO-1 would reduce the impact of construction activities on potentially unknown paleontological resources to a less-than-significant level by addressing discovery of unanticipated buried resources and preserving and/or recording those resources consistent with appropriate laws and requirements.

Mitigation Measure GEO-1: Inadvertent Discovery of Paleontological Resources
In the event that fossils are encountered during construction (i.e., bones, teeth, or unusually abundant and well-preserved invertebrates or plants), construction activities shall be diverted away from the discovery within 50 feet of the find, and a professional Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-29 palaeontologist shall be notified to document the discovery as needed, to evaluate the potential resource, and to assess the nature and importance of the find. Based on the scientific value or uniqueness of the find, the palaeontologist may record the find and allow work to continue, or recommend salvage and recovery of the material, if it is determined that the find cannot be avoided. The palaeontologist shall make recommendations for any necessary treatment that is consistent with currently accepted scientific practices. Any fossils collected from the area shall then be deposited in an accredited and permanent scientific institution where they will be properly curated and preserved.

Implementation of Mitigation Measure GEO-1 would reduce this impact to a less-than-significant level for both construction and operation because a plan to address discovery of unanticipated paleontological resources and to preserve and/or record those resources consistent with appropriate laws and requirements would be implemented.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-30 Greenhouse Gas Emissions
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
a) Generate greenhouse gas emissions,
either directly or indirectly, that may
have a significant impact on the
environment?

b) Conflict with an applicable plan, policy or
regulation adopted for the purpose of
reducing the emissions of greenhouse
gases?

The NCUAQMD has not adopted regulations regarding the evaluation of greenhouse gas (GHG) emissions in a CEQA document, and has not established CEQA significance criteria to determine the significance of impacts with regard to GHGs. The NCUAQMD recommends considering the GHG emission CEQA standards from the Bay Area Air Quality Management District (BAAQMD).

Pacific Gas & Electric provides energy to the WWTP.
a) Generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the environment? (Less than Significant) As provided by the BAAQMD’s CEQA Air Quality Guidelines, if a project meets the screening criteria for a Land Use Type, and the analysis is consistent with the methodology used to develop the screening criteria, then a project’s operational greenhouse gas impact for that Land Use Type may be considered less than significant. However, there is no Land Use Type applicable to a wastewater treatment facility, and Land Use Types related to industrial facilities assume large buildings would be constructed. Therefore, the following analysis quantifies greenhouse gas emissions from operation and compares it to the 1,100 MTCO2e per year threshold established by the BAAQMD.

For project construction, BAAQMD does not have quantitative GHG emission thresholds (BAAQMD 2017). Rather, the BAAQMD states that a lead agency should disclose GHG emission information and make a determination on the significance in relation to meeting AB 32 GHG reduction goals.

Project operation would result in greenhouse gas emissions from operation of the new pump station and one vehicle maintenance trip per week. The new pump station would require approximately 185,000 kWh of electricity each year, resulting in approximately 44 MTCO2e per year. Note, however, certain existing facilities would be taken off-line after construction of the new pump station. This would result in a smaller increase in greenhouse gas emissions, over existing conditions, than shown in Appendix A. As 44 MTCO2e is below the 1,100 MTCO2e threshold, the operational impact to greenhouse gas emissions from project operation would be less than significant.

Project construction activities would result in a temporary increase in greenhouse gas emissions, including exhaust emissions from on-road haul trucks, worker commute vehicles, and off-road heavy-duty equipment. Construction emissions were estimated using CalEEMod version 2016 (Appendix A). 3.2, and are estimated to be approximately 41.22 MTCO2e from all construction activities over the 8-month construction period. The project’s construction emissions equal 1.37 MTCO2e per year when annualized over the assumed 30-year lifespan of the project.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-31 Emissions during construction would not be a considerable contribution to the cumulative greenhouse gas impact, given that construction would be temporary, of short duration, and would not require a large fleet of earthmoving equipment and soil-off hauling beyond the normal equipment and activities related to such utility or infrastructure projects. Therefore, the project’s construction-related emissions would be less than significant. b) Conflict with an applicable plan, policy, or regulation adopted for the purpose of reducing the emissions of greenhouse gases? (Less than Significant) In 2008, the California Air Resources Board adopted the Climate Scoping Plan, which outlined measures to attain emissions standards pursuant to AB 32. The most recent update to the Scoping Plan was completed in December 2017. Although the Scoping Plan identifies strategies to meet statewide emissions reductions targets, it does not contain recommended reduction levels or percentages for local government’s municipal operations.

On a local level, Humboldt County’s 2012 Draft Climate Action Plan, which has yet to be adopted, also outlines targets consistent with AB 32. In addition, the NCUAQMD has not developed CEQA guidelines or significance thresholds for use in GHG analyses. Therefore, for the purpose of this analysis, the 2017 Scoping Plan was used as the evaluation criteria. If the project were to conflict with the 2017 Scoping Plan, then the project would have a significant impact.

The recommended measures in the 2017 Scoping Plan are broad policy and regulatory initiatives that would be implemented at the State level and do not relate to the construction and operation of individual infrastructure projects, such as the Wastewater Treatment and disposal System Upgrade Project. Although project construction may benefit (have a reduced generation of GHG) from implementation of some of the State-level regulations and policies related to fuel and vehicle efficiencies, the project would not impede the State in meeting the AB 32 greenhouse gas reduction goals. Therefore, impacts from the project’s construction and operational emissions would be less than significant.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-32 Hazards and Hazardous Materials
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
f) Create a significant hazard to the
public or the environment through
the routine transport, use, or disposal
of hazardous materials?

g) Create a significant hazard to the
public or the environment through
reasonably foreseeable upset and
accident conditions involving the
release of hazardous materials into
the environment?

h) Emit hazardous emissions or handle
hazardous or acutely hazardous
materials, substances, or waste
within one-quarter mile of an existing
or proposed school?

i) Be located on a site which is
included on a list of hazardous
materials sites compiled pursuant to
Government Code § 65962.5 and, as
a result, would it create a significant
hazard to the public or the
environment?

j) For a project located within an airport
land use plan or, where such a plan
has not been adopted, within two
miles of a public airport or public use
airport, would the project result in a
safety hazard or excessive noise for
people residing or working in the
project area?

k) Impair implementation of or
physically interfere with an adopted
emergency response plan or
emergency evacuation plan?

l) Expose people or structures, either
directly or indirectly, to a significant
risk of loss, injury or death involving
wildland fires?

This section evaluates the potential impacts related to hazards and hazardous materials during construction and operation of the project.
a) Create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials? (Less Than Significant Impact) Construction of the project would include the transport and use of common hazardous materials inherent to the construction process, including petroleum products for construction equipment and vehicles, paints, concrete curing compounds, and solvents for construction of project Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-33 improvements. These materials are commonly used during construction, are not acutely hazardous, and would be used in relatively small quantities.

Caltrans and the California Highway Patrol (CHP) regulate the transportation of hazardous materials and wastes, including container types and packaging requirements, as well as licensing and training for truck operators, chemical handlers, and hazardous waste haulers. The California Division of Occupational Safety and Health (Cal-OSHA) also enforces hazard communication program regulations which contain worker safety training and hazard information requirements, such as procedures for identifying and labeling hazardous substances, communicating hazard information related to hazardous substances and their handling, and preparation of health and safety plans to protect workers and employees.

Project construction would be required to implement storm water best management practices during construction in accordance with the State Water Resources Control Board General Construction Storm Water Permit. Best management practices addressing materials management would be required, including proper material delivery and storage, spill prevention and control, and management of concrete and other wastes.

Because the City and its contractors would be required to comply with existing and future hazardous materials laws and regulations and applicable best management practices addressing the transport, storage, use, and disposal of hazardous materials, the potential to create a significant hazard to the public or the environment during construction of the project would be less than significant.

Following construction, operation of the project would not result in the need for new hazardous materials that would need to be transported, used, or disposed. No operational impact would occur. b) Create a significant hazard to the public or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment?? (Less Than Significant Impact) The project would utilize heavy machinery to perform some construction-related tasks including grading, drilling, excavation, and transportation of materials. There is always the possibility when equipment is operating that an accident could occur and fuel could be released onto the soil.

Equipment on site during construction would be required to have emergency spill cleanup kits immediately accessible in the case of any fuel or oil spills. Equipment would not be refueled near the Eel River or any perennial wetland. If equipment must be washed, it would be washed off-site.

The potential impact would be less than significant.
c) Emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within one-quarter mile of an existing or proposed school? (Less Than Significant Impact)
The southern edge of the Fortuna Middle School track facility is located approximately 0.2 miles north of the WWTP parking lot. Construction activities are assumed to include the use of hazardous materials such as fuels, lubricants, degreasers, paints, and solvents. These materials are commonly used during construction, are not acutely hazardous, and would be used in small quantities. Numerous laws and regulations ensure the safe transportation, use, storage, and disposal of hazardous materials (see Impact discussion in Section 3.9 (a) and (b) above). Although construction activities could result in the inadvertent release of small quantities of hazardous substances, a spill or release at a construction area is not expected to endanger individuals at nearby schools given the nature of the materials, the small quantities that would be used, and the distance of the schools from the project area. Therefore, because the City and its contractors would Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-34 be required to comply with existing and future hazardous materials laws and regulations covering the transport, use, and disposal of hazardous materials, and because of the nature and quantity of the hazardous materials to be potentially used by the project, the impact related to the use of hazardous materials during construction adjacent to the school would be less than significant.

Project operations would have no impact on Fortuna Middle School or any other school. d) Be located on a site which is included on a list of hazardous materials sites compiled pursuant to Government Code § 65962.5 and, as a result, would it create a significant hazard to the public or the environment? (Less Than Significant Impact) The project is not located on or near a cleanup site listed in the California Department of Toxic Substances Control EnviroStor database (DTSC 2019). The project is not located on a cleanup site, as mapped in the GeoTracker database (State Water Resources Control Board 2019). A closed Leaking Underground Storage Tank (LUST) clean up site (Mercer Fraser Yard,T0602300101 is located adjacent to the WWTP at 81 Sandie Prairie Road. A second closed LUST clean up site is located due north of the WWTP (City of Fortuna Corporation Yard, T0602300177) at 190 Dinsmore Drive. Off-site construction activities are not planned, and impacts related to these two off-site closed clean up sites would not occur. The WWTP at 180 Dinsmore Drive, Fortuna, CA is listed on the Cortese List. The description of the violation requests repair or schedule of a new chlorine contact chamber. The chlorine contact chamber was replaced several years ago; thus it is believed this listing is outdated and no hazard remains as a result. The potential impact associated with hazardous materials sites would be less than significant. e) For a project located within an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project result in a safety hazard or excessive noise for people residing or working in the project area? (No Impact)
The nearest airport is the Rohnerville Airport, which is located more than two miles from the project area. There would be no impact.
f) Impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan? (No Impact) The City does not have an independent emergency response plan. However, the City does have hazardous material response plans associated with the regulatory requirements for their wastewater treatment, water treatment plant facilities and operations, and an emergency response plan that establishes chain-of-command and response procedures between the emergency services, public works, City staff and board, and other essential departments and outside organizations. The proposed project does not conflict with these plans.

The Humboldt County Emergency Operations Plan (Humboldt County 2015) does not designate specific evacuation routes or emergency shelter locations, or include policies or procedures with which the project would conflict. Therefore, the project would not impair implementation of or physically interfere with the plan. Additionally, the project would not increase public use, significantly increase risk of hazard occurrence, or construct facilities that may post a hazard to people or the environment. No impact would occur.
g) Expose people or structures, either directly or indirectly, to a significant risk of loss, injury or death involving wildland fires? (Less Than Significant Impact) The California Department of Forestry and Fire Protection (CAL FIRE) is required by law to map areas of significant fire hazards based on fuels, terrain, weather, and other relevant factors. These Fire Hazard Severity Zones (FHSZ) influence how people construct buildings and protect property Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-35 to reduce risk associated with wildland fires. The project site is primarily located in a local responsibility area (LRA) meaning an area where local governments have financial responsibility for wildland fire protection (Humboldt County 2019). Project areas located east of the Eel River are within the Fortuna Fire Protection District. Project areas located west of the Eel River are within the Ferndale Fire Protection District.

The project and surrounding vicinity is located in a moderate hazard severity zone, which is the lowest risk of all mapped categories (Humboldt County 2019). It is possible fire ignition could occur during construction (e.g. related to heavy machinery usage). The project would not otherwise increase exposure to wildlife fire above existing conditions. The impact would be less than significant.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-36 Hydrology and Water Quality
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
a) Violate any water quality standards or
waste discharge requirements or
otherwise substantially degrade surface
or ground water quality?

b) Substantially decrease groundwater
supplies or interfere substantially with
groundwater recharge such that the
project may impede sustainable
groundwater management of the basin?

c) Substantially alter the existing drainage
pattern of the site or area, including
through the alteration of the course of a
stream or river or through the addition of
impervious surfaces, in a manner which
would:

i) Result in substantial erosion or
siltation on- or off-site? 
ii) Substantially increase the rate or
amount of surface runoff in a
manner which would result in
flooding on- or off-site?

iii) Create or contribute runoff water
which would exceed the capacity of
existing or planned stormwater
drainage systems or provide
substantial additional sources of
polluted runoff?

iv) Impede or redirect flood flows? 
d) In flood hazard, tsunami, or seiche
zones, risk release of pollutants due to
project inundation?

e) Conflict with or obstruct implementation
of a water quality control plan or
sustainable groundwater management
plan?

The project is near Strongs Creek and the Eel River. In-water work would not occur; however, directional drilling would occur beneath the Eel River and Strongs Creek. a) Violate any water quality standards or waste discharge requirements or otherwise substantially degrade surface or ground water quality? (Less Than Significant with Mitigation)
If potential impacts to Waters or wetlands would occur, the project would be required to obtain and comply with necessary permits requirements required by Section 401 and Section 404 of the Clean Water Act and administered by NCRWQCB and USACE, respectively, acting to prevent or Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-37 essentially reduce the potential for the project and operations to violate any water quality standards or waste discharge requirements.

The greatest potential project impacts to water quality would result from sediment mobilization during construction and operations or a frac-out during horizontal drilling. Construction and operation activities such as site clearing, grading, excavation, and material stockpiling could leave soils exposed to rain or surface water runoff that may carry soil contaminants (e.g., nutrients or other pollutants) into wetlands and/or waterways near the site, degrade water quality, and potentially violate water quality standards for specific chemicals, dissolved oxygen, suspended sediment, or nutrients. This impact would be potentially significant. Directional drilling has the potential to release drilling fluids into the surface environment through frac-outs. A frac-out is a condition where drilling mud is released through fractured soils and bedrock into the surrounding rock and sand, which travels to the surface. This impact would also be potentially significant.

SWRCB Order No. 2009-0009 applies to public and private construction projects that include one or more acres of soil disturbance. Because the proposed project is anticipated to disturb over one (1) acre of land, compliance with Order No. 2009-0009 would be required. Therefore, if construction and operation activities associated with the project are not properly managed, applicable water quality standards and waste discharge requirements could be violated.

As described in Environmental Protection Action 2, the project and operations would obtain coverage under State Water Resources Control Board Order No. 2009-0009-DWQ, Waste Discharge Requirements for Discharges of Storm Water Runoff Associated with Construction and Land Disturbance Activities, as amended by Order No. 2012-0006. In compliance with the NPDES requirements, a Notice of Intent (NOI) would be prepared and submitted to the NCRWQCB, providing notification and intent to comply with the State of California Construction General Permit.

In addition, a Construction SWPPP would be prepared for pollution prevention and control prior to initiating site construction activities. The Construction SWPPP would identify and specify the use of erosion sediment control BMPs for control of pollutants in stormwater runoff during construction related activities, and would be designed to address water erosion control, sediment control, off-site tracking control, wind erosion control, non-stormwater management control, and waste management and materials pollution control. A sampling and monitoring program would be included in the Construction SWPPP that meets the requirements of the NCRWQCB to ensure the BMPs are effective. A Qualified SWPPP Practitioner would oversee implementation of the SWPPP, including visual inspections, sampling and analysis, and ensuring overall compliance.

Additionally, water sourced from dewatering activities would be pumped into Baker tanks (or similar) or dewatering bags and used for dust control purposes, consistent with Mitigation Measure AIR-1. Water sourced from dewatering would not be illegally discharged to wetlands or cause polluted runoff.

Mitigation
The potential impact to water quality standards would be less than significant with the incorporation of Mitigation Measure HWQ-1 and HWQ-2 protecting against water quality impacts related to sedimentation, erosion, hazardous materials, or a frac-out.

Mitigation Measure HWQ-1: Implement Best Management Practices to Protect Water Quality
Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-38 The following representative Best Management Practices will be implemented to protect water quality during construction to avoid impacts to water quality:
• All contractors that would be performing demolition, construction, grading, operations or other work that could cause increased water pollution conditions at the site (e.g., dispersal of soils) shall receive training regarding the environmental sensitivity of the site and need to minimize impacts. Contractors also shall be trained in implementation of stormwater BMPs for protection of water quality. • The Contractor will implement BMPs during construction including the following BMPs from the current California Stormwater BMP Handbook for Construction:

EC-1: Scheduling; EC-2: Preservation of Existing Vegetation; NS-2: Dewatering Operations; NS-9: Vehicle Equipment and Fueling; NS-10: Vehicle & Equipment Maintenance; WM-2: Material Use; and WM-4: Spill Prevention and Control; • Contractors will be responsible for minimizing erosion and preventing the transport of sediment to sensitive areas;
• Sufficient erosion control supplies will be maintained on site at all times, available for prompt use in areas susceptible to erosion during rain events; • Disturbance of existing vegetation will be minimized to only that necessary to complete the work;
• The contractor will make adequate preparations, including training and providing equipment, to contain oil and/or other hazardous materials spills; • Dewatering operations will be conducted where needed from the work location and stored or disposed of appropriately;
• Vehicle and equipment maintenance should be performed off-site whenever practical;
• Contractor shall ensure that the site is prepared with BMPs prior to the onset of any storm predicted to receive 0.5 inches or more of rain over 24 hours; and • All erosion and sediment control measures shall be maintained in accordance to their respective BMP fact sheet until disturbed areas are stabilized; Mitigation Measure HWQ-2: Development of a Horizontal Directional Drilling Hydrofracture Contingency Plan
To avoid potential impacts related to a frac-out, a Horizontal Directional Drilling Hydrofracture Contingency Plan for horizontal directional drilling pipeline under the Eel River and Strongs Creek shall be in place prior to construction. The Plan shall include an anticipated drilling mud design that provides engineering properties and the anticipated fluid pressure required as the pilot hole is incrementally advanced in approximately 10- meter (30-foot) increments. The contractor shall be required to monitor and record the Driller’s Mud composition, drill fluid pressure and volumes, and have an inadvertent return contingency plan and associated equipment to minimize impacts. The Driller’s Mud, spoils, water, and all other waste materials are to be legally disposed with weight or volume tickets confirming legal disposal. The Plan shall include: visual monitoring, monitoring pressures and volumes, observation during drilling, standards and specification for a four-hour shutdown minimum if frac-out occurs to allow ground to heal, cleanup plan, frac-out tank or vac truck (placed in strategic locations), and roles and responsibilities in the event of a frac-out event.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-39 Implementation of Mitigation Measure HWQ-1 and HWQ-2 would mitigate potential impacts related to water quality standards and waste discharge requirements to a less-than-significant level by appropriately managing construction dewatering and implementing erosion control measures near streams and other wetted waters of the U.S. or State and developing a contingency plan to avoid environmental impacts resulting from a frac-out during direction drilling.
b) Substantially decrease groundwater supplies or interfere substantially with groundwater recharge such that the project may impede sustainable groundwater management of the basin? (Less Than Significant)
The project would not increase impervious surface to limit recharge and would not pump or utilize groundwater resources. Similarly, the project would not decrease groundwater supplies or interfere with groundwater management. During construction, isolated and short-duration groundwater dewatering may occur as needed. Dewatering would be small in scale and limited to shallow groundwater only. The impact would be less than significant. c, i) Substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river or through the addition of impervious surfaces, in a manner which would result in substantial erosion or siltation on- or off-site? (Less Than Significant Impact)
The drainage pattern of the eastern project area at the WWTP is limited to unpaved gravel stockpiling areas and the developed WWTP facility. Project elements would not result in significant alteration of the existing drainage pattern of the site, and the WWTP does not include a stream or watercourse. Cessation of use of the percolation ponds during low flow periods would serve to hydrological disconnect WWTP operations from the Eel River, reducing the associated risk to water quality, unrelated to erosion and siltation. The potential impact at the WWTP facility would be less than significant.

Potential development of a contingency mid-point drill pit would not alter the drainage pattern of the Eel River, even locally. Project construction to occur at the western percolation field would also not alter the drainage pattern of the project area, including areas of temporary staging and permanent access. Planned grading would not significantly alter slope or drainage and would be entirely pervious. Implementation of Mitigation Measure HWQ-1 and Mitigation Measure HWQ-2 would further serve to avoid potential water quality impacts associated with erosion or siltation during construction. The potential impact would be less than significant. c, ii) Substantially increase the rate or amount of surface runoff in a manner which would result in flooding on- or off-site? (No Impact)
The project would not increase impervious surfaces or substantially alter topography, slope, or drainage to or near the Eel River, Strongs Creek, or any other tributary. Both on-site and off-site flooding would remain unaffected. No impact would result. c, iii) Create or contribute runoff water which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff? (Less Than Significant)
The project does not involve paving and would not increase the area of impervious surface. The project also does not include elements that would increase stormwater drainage or necessitate significant design features to accommodate stormwater management. Additionally, in compliance with Environmental Protection Action 2, the project would develop a SWPPP to be approved by the NCRWCB, and the project would be designed to meet NCRQWB storm water requirements. The Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-40 project would not cause on- or off-site flooding. The impact would be less than significant c, iv) Impede or redirect flood flows? (Less Than Significant) The project is located entirely within the FEMA 100-year flood zone of the Eel River and Strongs Creek (Humboldt County 2019). However, all project elements located in the western percolation field would be located at or below grade and would not impede or redirect flood flows. Existing topography would not be significantly altered in such a manner as to redirect flood flows. Similarly, the underground pipe connecting the WWTP to the percolation field on the opposite bank of the Eel River would also not impede or redirect flood flows because it would be below ground surface.

Treatment upgrades at the WWTP would not increase the footprint or structure height (e.g. facility buildings) of the overall WWTP facility and associated infrastructure beyond existing conditions.

The potential impact would be less than significant.
d) In flood hazard, tsunami, or seiche zones, risk release of pollutants due to project inundation? (Less Than Significant)
The project site is not located near a larger isolated body of water that may be affected by a seiche.

A portion of the WWTP nearest the Eel River is located within a Tsunami Evacuation Area. The entire project is also located within the FEMA 100-year flood zone.

If a tsunami occurred during construction, pollutants from heavy machinery (e.g. diesel) could be released into the environment. In the event of tsunami that was severe enough to extend to the eastern edge of the Tsunami Evacuation Area, the cumulative environmental and human impact would be catastrophic and the impact directly attributable to the proposed project would be insubstantial by comparison. Project construction would not occur during winter months when floods are known to occur. The impact associated with project construction would be less than significant.

Operationally, chemicals or other hazardous materials would not be present or in use at the western percolation facility. Aside from the optional use of aluminum-based metal coagulants to support potential UV disinfection and supplemental carbon for the nitrification reaction, no new chemicals will be used as a result of the project. In the event of a very significant flood that might inundate or wash away WWTP infrastructure, these constituents and wastewater effluent could be released into the Eel River. The flood magnitude associated with such an event would be both uncommon and significant. Inadvertent release of any constituents present at the WWTP would quickly dilute within the Eel River floodwaters. The potential impact of pollutants to water quality due to project inundation would be less than significant. e) Conflict with or obstruct implementation of a water quality control plan or sustainable groundwater management plan? (No Impact)
The relevant water quality control plan is the NCRWQCB Basin Plan, which establishes thresholds for key water resource protection objectives for both surface waters and groundwater. The project shall obtain coverage under State Water Resources Control Board Order No. 2009-0009-DWQ, Waste Discharge Requirements for Discharges of Storm Water Runoff Associated with Construction and Land Disturbance Activities, which would include a SWPPP. If impacts to Waters or wetlands would occur, the project shall also obtain a NCRWCB Clean Water Act Section 401 Water Quality Certification. These regulatory requirements and associated requisite monitoring would ensure a conflict with the Basin Plan does not occur. Additionally, by removing the hydrologic interaction between the existing percolation ponds at the WWTP, the Eel River, and groundwater table, the project would benefit management of groundwater as described in the Basin Plan, resulting in an improvement. No impact would result.
we are fully
contained by a
berm at the BFE at
the WWTP itself
Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-41 Land Use and Planning
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
a) Physically divide an established
community?

b) Cause a significant environmental
impact due to a conflict with any land
use plan, policy, or regulation adopted
for the purpose of avoiding or mitigating
an environmental effect?

This section evaluates the potential impacts related to land use, as it applies to construction and operation of the project.
a) Physically divide an established community? (No Impact) The project would not physically divide a community. The WWTP project area is occupied by an existing facility whose project related improvements would be constructed entirely within the existing boundaries of the WWTP. The surrounding land uses are commercial or industrial in nature, with no residential uses present. Access to the site and surrounding properties is provided exclusively by Dinsmore Drive, a frontage road along Highway 101. There are no multi-use trails in the immediate project facility, though the northernmost extent of the River Walk Trail lies approximately 1,000 feet south of the project. Because the project does not result in modification of roadway or trail configuration, it does not create a physical barrier to the movement of people or motor vehicles.

The western project area at and near the percolation field consists of open space surrounded by forest and agricultural uses. There are no residential or commercial uses in the vicinity. The project would result in a minor extension and improvement of the existing farm road. No roads or formally designated trails would be closed or realigned as a result of this project. Existing off-road vehicle tracks appear unplanned and unmaintained. There are no formally designated multi-use trails in the vicinity of the western project area. For the reasons stated above, the proposed project would not divide an established community. There would be no impact. b) Cause a significant environmental impact due to a conflict with any land use plan, policy, or regulation adopted for the purpose of avoiding or mitigating an environmental effect? (No Impact)
The project is consistent with the City of Fortuna and Humboldt County land use and zoning designations. The eastern project area (Fortuna jurisdiction) is zoned Public Facilities (PF) and has a land use designation of Public (PUB). “Sewage treatment plant” is a conditionally permitted use in the Public Facilities (PF) zone district. The Public Facilities (PF) zone district is consistent with and implements the Public (PUB) land use designation, as sourced from the Fortuna General Plan.

The western project area that would contain the leach field (County of Humboldt jurisdiction) is zoned Agriculture Exclusive, Archeological Resource Area, Streams and Riparian Corridors Protection, Transitional Agricultural Lands (AE-60/A, F, R, T) with a land use designation of AE (Agriculture Exclusive). “Solid Waste Disposal” is a conditionally permitted use in the Agriculture Exclusive zone district. The Agriculture Exclusive zone district is consistent with and implements the Agriculture Exclusive land use designation, as source from the County of Humboldt General Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-42 Plan.

The contingency directional mid drilling point located on the Eel River floodplain (County of Humboldt jurisdiction) is zoned Natural Resources, Streams and Riparian Corridors protection (NR/R) with a land use designation of NR. “Civic Use Types” such as oil and gas pipelines are a conditionally permitted use in the Natural Resource zone. While not specifically listed, the proposed project is sufficiently similar and compatible to the uses permitted in the Natural Resource zone.

The Natural Resource zone district is consistent with and implements the Natural Resource land use designation, as sourced from the County of Humboldt General Plan. For the reasons stated above, the proposed project would not conflict with any land use plan, policy, or regulation.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-43 Mineral Resources
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
f) Result in the loss of availability of a
known mineral resource that would be
of value to the region and the residents
of the state?

g) Result in the loss of availability of a
locally-important mineral resource
recovery site delineated on a local
general plan, specific plan or other land
use plan?

This section evaluates the potential impacts related to mineral resources associated with the project. Aside from the gravel located on the Eel River floodplain, there are no additional mineral resources in the project area.
a, b) Result in the loss of availability of a known mineral resource that would be of value to the region and the residents of the state, or a locally-important mineral resource recovery site delineated on a local general plan, specific plan or other land use plan? (No Impact)
Construction of the proposed project would not result in the loss of mineral resources. Aside from the floodplain gravel, there are no mineral resources found within the project area. Floodplain gravel would not be harvested, removed, or permanently disturbed as a result of project actions. The project does not require a substantial amount of any mineral resource for construction, although some mineral resources (primarily aggregate and rock) would be needed for construction. Therefore, no impact would occur.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-44 Noise
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
a) Result in generation of a
substantial temporary or
permanent increase in
ambient noise levels in the
vicinity of the project in
excess of standards
established in the local
general plan or noise
ordinance, or applicable
standards of other agencies?

b) Result in generation of
excessive groundborne
vibration or noise levels?

c) For a project located within
the vicinity of a private airstrip
or an airport land use plan or,
where such a plan has not
been adopted, within two
miles of a public airport or
public use airport, would the
project expose people
residing or working in the
project area to excessive
noise levels?

Current noise conditions on the eastern project area consist of noise associated with the operation of the Fortuna WWTP e.g. mechanical equipment, motors and truck traffic. Background noise is generated by vehicles on Highway 101, Dinsmore Drive, emergency response sirens related to the nearby fire station, and the industrial facilities (aggregate production) located to the north and south of the project area. Current conditions on the western edge of the project are typical of forest and agricultural land, which typically experience minimal noise except that created by agricultural vehicles such as tractors on nearby fields.
a) Result in generation of a substantial temporary or permanent increase in ambient noise levels in the vicinity of the project in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies? (Less Than Significant Impact)
Construction of the proposed project would temporarily increase noise in the immediate vicinity of the project site. The temporary noise increases would result from use of construction equipment for the project, as well as from increased traffic as construction workers commute to and from the project site. To prevent noise disturbance to the community, City of Fortuna General Plan Noise Element Policy HS-6 limits construction activity to the hours between 7 a.m. and 8 p.m. Monday through Saturday, except for emergencies or other permitted circumstances.

There are no sensitive noise receptors, such as housing or schools that are located adjacent to the project area. The nearest noise receptor include: 1) the Fortuna Middle School track facility, which is located approximately 0.2 miles north of the WWTP parking lot and 2) residential housing, Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-45 located approximately 0.1 miles north and west of the WWTP parking lot. Both Fortuna Middle School and residential housing are located on the opposite side of Highway 101, which also produces large amounts of highway-related noise. Existing stationary noise sources located near the WWTP, as documented in the City’s General Plan, include: Mercer-Fraser Gravel Operations and the Eel River Disposal Transfer Station. The project would generate temporary noise during construction. Noise levels would be consistent with the reference noise levels in Table 3.13-1 below.

Table 3.13-1: Construction Equipment Reference Noise Levels as Measured at 50’
Equipment
Noise Level
(dB0F
1) Equipment
Noise Level
(dB)
Drill rig truck 84 Jackhammer 85
Horizontal Boring Hydraulic Jack 80 Large Generator 82
Front end loader or Backhoe 80 Paver or Roller 85
Excavator 85 Dump truck 84
Source: Federal Highway Administration, 2006.

Sound from a point source is known to attenuate at a rate of -6 dB for each doubling of distance.

For example, a noise level of 84 dB Leq as measured at 50 feet from the noise source would attenuate to 78 dB Leq at 100 feet from the source and to 72 dB Leq at 200 feet from the source to the receptor. Based on the reference noise levels in Table 3.13-1, the noise levels generated by construction equipment at the project site may reach a maximum of approximately 85 dB Leq at 50 feet during site excavation and construction.

The project is not expected to result in a substantial increase in ambient noise levels on the eastern project area because new pumps would be installed within the existing concrete wet well structure.

The project is not expected to increase ambient noise levels at the western project area (effluent percolation field) because this project component is limited to buried pipes with no associated mechanical equipment. The impact would therefore be less than significant.

Noise Ordinance Compatibility
City Fortuna
The City of Fortuna General Plan designates a daytime exterior maximum noise threshold of 85 dBA Lmax in industrial zoning districts. The project would be fully permitted and would comply with terms of approved permits, including those that specifically address noise limitations. The project would not conflict with the City’s noise policies.

Humboldt County
The Humboldt County’s Noise Compatibility Standards set a construction noise range from a maximum of 65 dB – 85 dB, depending on the land use. However, exceptions include the use of heavy machinery and tools used during construction of permitted structures when conforming to the terms of the approved Use Permit (Humboldt County 2017d). The project would obtain a Use Permit and would comply with terms of the approved permit, including those that specifically address noise limitations. The project would not conflict with Humboldt County’s Noise Element or Noise Compatibility Standards.
1 “dB” is a weighted decibel measurement for assessing hearing risk and, therefore, is used by most regulatory compliance.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-46 Noise and Land Use Compatibility
Construction
The project area consists of two separate sites. The eastern portion consists of the existing WWTP and the western portion consists of the new effluent percolation fields. Both sites would experience temporary increases in noise due to construction activities. However, these would occur during daytime hours only and within the established regulatory limits discussed above, including daytime exterior maximum noise threshold of 85 dBA Lmax for construction at and near the WWTP.

Construction in western project areas (jurisdiction of Humboldt County) are exempt from noise thresholds during construction under the project’s Use Permit. The potential impact would be less than significant.

Operation
After construction, increased operational noise generated by the project on the eastern side of the project area is expected to be minimal to non-existent due the indoor installation of the new pumps and other associated upgrades (converting the aeration basins to Modified Ludzack Ettinger (MLE) process as well as modifying the WAS and EQ basins.) There would be no increase in ambient noise resulting from the new effluent percolation fields because no equipment is being installed that is capable of creating noise. The potential impact would be less than significant. b) Result in generation of excessive groundborne vibration or noise levels? (Less Than Significant Impact)
Earth moving and earth compacting activities using heavy machinery would create groundborne vibrations and noise that may be noticeable on a temporary basis during construction activities at nearby commercial and industrial uses. Noticeable groundborne vibrations and noise would be limited to normal daytime hours. The proposed project would comply with Fortuna General Plan Policy HS-6 and Humboldt County General Plan policy N-IM6, which requires limiting construction activity to specified daytime hours and regulate vibration sources. Additional groundborne vibrations beyond baseline conditions are not anticipated as a result of operational activities, and the potential impact would be less than significant.
c) For a project located within the vicinity of a private airstrip or an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project expose people residing or working in the project area to excessive noise levels? (No Impact)
The project is not located within the vicinity of a private airstrip or an airport land use plan, or within two miles of a public airport. There would be no impact. delete sentence in
parenthesis
Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-47 Population and Housing
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
a) Induce substantial unplanned
population growth in an area,
either directly (for example, by
proposing new homes and
businesses) or indirectly (for
example, through extension of
roads or other infrastructure)?

b) Displace substantial numbers of
existing people or housing,
necessitating the construction of
replacement housing
elsewhere?

a) Induce substantial unplanned population growth in an area, either directly (for example, by proposing new homes and businesses) or indirectly (for example, through extension of roads or other infrastructure)? (No Impact) The proposed project does not include components that would directly support unplanned population growth, such as new housing, roads, utilities, or other developments. The key element of the project is the effluent percolation field, which is being constructed to provide an alternative to the current system of discharging effluent into two WWTP percolation ponds. This alternative is necessary due to regulatory conditions imposed by the NCRWQCB. As such, the project does not increase sewer capacity for the City of Fortuna in such a manner as to induce population growth.

The project would result in a minor farm road extension and gravel road resurfacing in the vicinity of the effluent percolation fields. These access-related improvements do not appreciably change the nature of the roads (e.g. dirt road to paved residential street) and therefore would not encourage or induce population growth in the project area. There would be no impact. b) Displace substantial numbers of existing people or housing, necessitating the construction of replacement housing elsewhere? (No Impact) The proposed project would not displace people or housing or otherwise effect housing because there is no housing located in the immediate vicinity of the project area and the project does not include modification or construction of housing. There would be no impact.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-48 Public Services
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
a) Would the project result in substantial
adverse physical impacts associated
with the provision of new or physically
altered governmental facilities, need for
new or physically altered governmental
facilities, the construction of which could
cause significant environmental
impacts, in order to maintain acceptable
service ratios, response times or other
performance objectives for any of the
public services:

Fire Protection? 
Police protection? 
Schools? 
Parks? 
Other public facilities? 
The project would result in an overall benefit to public services by improving the WWTP and ensuring compliance with related regulations and regulatory guidance from the NCRWQCB directing the City of Fortuna to identify and implement alternative means of effluent disposal during Eel River low flow periods to protect water quality.
a) Would the project result in substantial adverse physical impacts associated with the provision of new or physically altered governmental facilities, need for new or physically altered governmental facilities, the construction of which could cause significant environmental impacts, in order to maintain acceptable service ratios, response times or other performance objectives for public services? (No Impact) While the project would alter the WWTP and expand the footprint of treatment facilities to the western side of the Eel River, such actions would not increase the intensity of the activity in the project area to the point that additional public services are needed. The eastern project area currently receives fire protection services consistent with the rest of Fortuna. The project improvements at the WWTP would not result in the need to increase staffing, create new hazardous conditions, or result in a modification to the road system that would restrict access for emergency services. The project improvements located on the effluent percolation fields are non-flammable and unstaffed.

Additional police protection is not required because the project would not result in increases to facility staffing at the WWTP. The unstaffed effluent percolation field consists largely of buried infrastructure unlikely to be the target of theft or vandalism.

The project would not affect schools because it would not induce population growth in school-age children. Further, there are no schools in the vicinity of the project area that may be physically impacted. The Fortuna dog park is located near the Fortuna WWTP and would not be affected by the project. For the reasons stated above, the project would not result in an impact to public services.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-49 Recreation
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
a) Increase the use of existing
neighborhood and regional parks or
other recreational facilities such that
substantial physical deterioration of the
facility would occur or be accelerated?

b) Include recreational facilities or require
the construction or expansion of
recreational facilities, which might have
an adverse physical effect on the
environment?

One park is located near the project area. The Fortuna dog park is located on Dinsmore Drive south of the Fortuna WWTP. The site of the future effluent percolation field has historically been used by off-road vehicles, though it is not clear that these activities have been done legally and/or with permission from the landowner.
a) Increase the use of existing neighborhood and regional parks or other recreational facilities such that substantial physical deterioration of the facility would occur or be accelerated? (No Impact)
The proposed project would not increase the use of or impact existing neighborhood parks or recreational facilities. Fortuna dog park is an established park located near the northern terminus of the River Walk Trail and south of the WWTP. Because the project would not increase staffing at the WWTP, nor increase residential uses in the vicinity of the WWTP, the Fortuna dog park would not experience an increase in usage as a result of the project.

Informal and illegal use by off-road vehicle users at the effluent percolation field site would likely decrease during the construction phase of the project because the site would be graded, thereby destroying the existing tracks and jumps. Following construction, the City would restrict illegal offroad vehicle use to prevent impacts to operational use of the facility, including establishing vegetation planted for erosion control purposes or to comply with required compensatory mitigation of any impacted wetlands or ESHA (see Mitigation Measure BIO-5 and BIO-7). There would be no impact.
b) Include or require the construction or expansion of recreational facilities, which might have an adverse physical effect on the environment? (No Impact) The construction or expansion of recreational facilities would not be required by the project or included in the project. There would be no impact.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-50 Transportation
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
a) Conflict with a program plan, ordinance
or policy addressing the circulation
system, including transit, roadway,
bicycle and pedestrian facilities?

b) Conflict or be inconsistent with CEQA
Guidelines § 15064.3, subdivision (b)? 
c) Substantially increase hazards due to a
geometric design feature (e.g., sharp
curves or dangerous intersections) or
incompatible uses (e.g., farm
equipment)?

d) Result in inadequate emergency
access? 
The project consists of improvements to the WWTP, the drilling of a conveyance pipe under the Eel River, and the installation of an effluent percolation field on the west side of the river. The project involves very minor modifications to the road network. Modifications to the road network are the minimum necessary for operations and maintenance.
a) Conflict with a program plan, ordinance or policy addressing the circulation system, including transit, roadway, bicycle and pedestrian facilities? (No Impact) City of Fortuna
The project would not involve any modification to existing roads in the vicinity of the WWTP. The WWTP is accessed solely by Dinsmore Drive and would remain so during all construction activities and operationally post-project. Because no streets would be modified, there is no conflict with a circulation-related program plan, ordinance, or policy of the City of Fortuna.

Humboldt County
Renner Lane, a gravel road, currently terminates at a privately owned farm. From this point, access would be provided via what is currently a privately-owned farm road. This farm road terminates at the edge of the field approximately 800 feet from the project site. The existing farm road would be improved by adding aggregate base and grading. The farm road would be extended from its terminus at the field’s edge to the percolation field. The new farm road section would be constructed to match the specifications of the existing portion. The City of Fortuna would procure an easement or other legal right through the private property to create legal access.

These activities do not conflict with any of the goals or policies contained in the Humboldt County General Plan Circulation Element. Renner Lane is currently a dead end road that serves a small number of parcels. The proposed road extension would not constitute an extension of the County of Humboldt roadway network; rather it would be a privately owned and maintained maintenance access road.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-51 Construction
The anticipated access route to the new waste water disposal area utilizes Highway 211 near Ferndale, California. Local roads then connect Waddington Road to Pleasant Point Road. The access road along existing farm roads would connect to Pleasant Point Road and Renner Lane and provide access to the site. Construction-related traffic would be limited to equipment mobilization at the new subsurface effluent percolation field area and daily personnel travel. Due to the rural nature of the area, existing low levels of traffic, and anticipated low levels of construction-related traffic, there would not be a need for formal traffic control.

Construction traffic would be limited to earthwork and directional drilling equipment and related support vehicles. Due to the minimal construction traffic anticipated at the WWTP, traffic control would not be necessary. Approximately 40 daily haul trips are anticipated on a peak day. Up to four work-weeks of peak days may occur.
b) Conflict or be inconsistent with CEQA Guidelines § 15064.3, subdivision (b)? (Less Than Significant Impact)
The provisions included in § 15034.3 are not applicable statewide until July 1, 2020. The following discussion is included prospectively. § 15064.3, subdivision (b), of the CEQA Guidelines lists the criteria for analyzing transportation impacts from proposed projects. The criteria are broken up into four categories, including land use projects, transportation projects, qualitative analysis, and methodology. Transportation projects that reduce, or have no impact on, vehicle miles traveled should be presumed to cause a less than significant transportation impact. For roadway capacity projects, agencies have discretion to determine the appropriate measure of transportation impact consistent with CEQA and other applicable requirements. Because the proposed project’s effects on roadways is limited to minor grading and an extension of a gravel maintenance access road, there would be no impact on vehicle miles travels as a result of construction. Operationally, City staff would visit the percolation field weekly (one vehicle only), which would result in a slight increase in vehicle miles traveled over the life of the project. In the project area, thresholds have not yet been established for vehicle miles traveled; however, slight increases in construction-related or operational-related vehicle miles traveled would not impact or reduce the Level of Service of associated roadways. The impact would be less than significant.
c) Substantially increase hazards due to a geometric design feature (e.g., sharp curves or dangerous intersections) or incompatible uses (e.g., farm equipment)? (No Impact)
The road-related improvements and extension are limited in nature and would result in a narrow, low speed, gravel access road on a private roadway to access western project areas (percolation field). Because of the design of the road and the limited number of vehicles (farm-related and/or percolation field-related), uses would not prove to be incompatible. Further, there is minimal tall vegetation along the access road that would block visibility, nor does the road have sharp turns.

Construction on or near public roadways would not occur. For these reasons, there would be no hazards due to a geometric design feature or incompatible use would not occur. There would be no impact.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-52 d) Result in inadequate emergency access? (Less Than Significant) Construction activities would primarily occur primarily outside of the public right-of-way. During construction, Dinsmore Drive and Renner Lane/Pleasant Point Road/Waddington Road would experience limited construction-related traffic. Construction related traffic would consist of earthwork and directional drilling equipment and support vehicles. Construction-related road or lane closures are not expected, and emergency access would not be limited. The potential impact would be less than significant.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-53 Tribal Cultural Resources
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
a) Cause a substantial adverse change in
the significance of a tribal cultural
resource listed or eligible for listing in
the California Register of Historic
Resources, or in a local register of
historic resources as defined in Public
Resources Code § 5020.1(k)?

b) Cause a substantial adverse change in
the significance of a tribal cultural
resource that is a resource determined
by the lead agency, in its discretion and
supported by substantial evidence, to be
significant pursuant to the criteria set
forth in subdivision (c) of the Public
Resources Code § 5024.1? In applying
the criteria set forth in subdivision (c) of
the Public Resources Code § 5024.1,
the lead agency shall consider the
significance of the resource to a
California Native American Tribe.

a, b) Cause a substantial adverse change in the significance of a tribal cultural resource? (Less Than Significant with Mitigation)
CEQA requires lead agencies to determine if a proposed project would have a significant effect on tribal cultural resources. The CEQA Guidelines define tribal cultural resources as: (1) a site, feature, place, cultural landscape, sacred place, or object with cultural value to a California Native American Tribe that is listed or eligible for listing on the California Register of Historical Resources, or on a local register of historical resources as defined in Public Resources Code Section 5020.1(k); or (2) a resource determined by the lead agency, in its discretion and supported by substantial evidence, to be significant according to the historical register criteria in Public Resources Code Section 5024.1(c), and considering the significance of the resource to a California Native American tribe.

An archeological survey and Historic Property Identification Report (HPIR) was completed during December 2019 (DZC 2019). In conjunction with the archeological survey and report, the local Tribal Historic Preservation Officers (THPOs) and NAHC were consulted. No Sacred Lands were identified within the APE. However, one previously recorded historical resource, as defined in § 15064.5, is reported as located within or immediately adjacent to the project APE. The historical resource is the ethnographic Wiyot village of kwigërgoyok. This resource is eligible for listing on the California Register of Historic Resources (DZC 2019). Although the area is subject to periodic river flooding and surficial remains of the resource were not located during pedestrian surveys, there is a potential for discovery of the site during project activities and a subsequent potential to cause a substantial adverse change in the significance of a historical resource pursuant to § 15064.5. The impact is considered significant.

Implementation of Mitigation Measures CUL-1 and CUL-2 (see Section 3.5, Cultural Resources) would reduce the potential impact to tribal resources by requiring construction worker training, Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-54 construction monitoring, and procedures in the event of inadvertent discovery consistent with appropriate laws and requirements.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-55 Utilities and Service Systems
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
Would the project:
a) Require or result in the relocation or
construction of new or expanded water,
wastewater treatment or storm water
drainage, electrical power, natural gas,
or telecommunications facilities, the
construction or relocation of which
could cause significant environmental
effects?

b) Have sufficient water supplies available
to serve the project and reasonably
foreseeable future development during
normal, dry and multiple dry years?

c) Result in a determination by the
wastewater treatment provider which
serves or may serve the project that it
has adequate capacity to serve the
project’s projected demand in addition
to the provider’s existing commitments?

d) Generate solid waste in excess of State
or local standards, or in excess of the
capacity of local infrastructure, or
otherwise impair the attainment of solid
waste reduction goals?

e) Comply with federal, state, and local
management and reduction statutes
and regulations related to solid waste?

The project is a public utility project designed to upgrade treatment operations at the WWTP and develop a new percolation field for treated effluent disposal during summer and fall during Eel River flow periods, benefiting the City and its populous and protecting the water quality of the Eel River from potential impacts associated with existing treatment and disposal operations. a) Require or result in the relocation or construction of new or expanded water, wastewater treatment or storm water drainage, electrical power, natural gas, or telecommunications facilities, the construction or relocation of which could cause significant environmental effects? (No Impact)
The project would result in the creation of new wastewater treatment infrastructure. Improvements to the existing Fortuna WWTP would involve adding Biological Nutrient Removal (BNR) to the existing treatment train, which would include converting the aeration basins to Modified Ludzack Ettinger (MLE) process as well as modifying the WAS and EQ basins. This improvement would take place within the site boundaries of the existing WWTP. A conveyance pipe would be drilled under the Eel River and would connect the WWTP to the new effluent percolation field located on the west side of the river. This project does not involve the construction of water, storm water, electrical, natural gas, or telecommunications infrastructure/facilities.

The project includes upgraded wastewater treatment facilities whose potential environmental list improvements
from new section

1.6.5, or just
reference them by
section
Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-56 impacts are evaluated as part of this Initial Study/Proposed Mitigated Negative Declaration. The following subjects are related to the proposed storm water drainage facilities, and are evaluated in other sections of this document:
 Potential impacts related to biological resources are evaluated in Section 3.4 (Biological Resources).
 Potential impacts related to cultural resources are evaluated in Section 3.5 (Cultural Resources).
 Potential impacts related to hydrology and water quality are evaluated in Section 3.9 (Hydrology and Water Quality).

No additional wastewater infrastructure or expansion of existing facilities beyond those identified in the project description and evaluated in this Initial Study are required. Therefore, no additional impact would occur.
b) Have sufficient water supplies available to serve the project and reasonably foreseeable future development during normal, dry and multiple dry years? (No Impact)
During construction, City water supplies or local wells could potentially be used for dust control and other activities. Construction-related water demands would be short-term and minimal in volume.

Following construction, the project would not directly or indirectly induce population growth and would not result in an increased demand for water. Therefore, no new entitlements or facilities would be required. No impact would occur.
c) Result in a determination by the wastewater treatment provider which serves or may serve the project that it has adequate capacity to serve the project’s projected demand in addition to the provider’s existing commitments? (No Impact) The project would not directly or indirectly induce population growth and would not increase the amount of wastewater generated. The project would result in improvements to the existing wastewater treatment infrastructure and would not increase wastewater treatment capacity. The WWTP would remain operational during construction; service would not be disrupted. No impact would occur.
d) Generate solid waste in excess of State or local standards, or in excess of the capacity of local infrastructure, or otherwise impair the attainment of solid waste reduction goals? (Less Than Significant)
Construction of the project would result in a temporary increase in solid waste disposal needs associated with demolition and construction wastes. Construction wastes would include, but not be limited to, excavated soils, construction waste resulting from the treatment upgrades at the WWTP including demolition of the compost storage, cleared trees/vegetation/top soils from the percolation fields and access road. Construction waste with no practical reuse or that cannot be salvaged or recycled would be legally disposed of at a local transfer station. Active permitted in-County transfer stations include the Humboldt Waste Management Authority facilities in Eureka or Samoa, California and the Recology Eel River Transfer Station in Fortuna, California. Solid waste generated by the project would represent a small fraction of the daily permitted tonnage of these facilities. This would be a less than significant impact on landfill capacity with the implementation of federal, state, and local statutes and regulations related to solid waste. Therefore, the project’s constructionrelated solid waste disposal needs would be sufficiently accommodated by existing landfills, and the impact would be less than significant. Following construction, project operation would not generate Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-57 additional solid waste. No operational impact would occur. e) Comply with federal, state, and local management and reduction statutes and regulations related to solid waste? (No Impact)
No applicable federal solid waste regulations would apply to the project. At the State level, the Integrated Waste Management Act mandates a reduction of waste being disposed and establishes an integrated framework for program implementation, solid waste planning, and solid waste facility and landfill compliance. The project would not conflict with or impede implementation of such programs. Following construction, project operation would not generate additional solid waste.

Therefore, no constructional or operational impact would occur.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-58 Wildfire
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
If located in or near state responsibility
areas or lands classified as very high fire
hazard severity zones, would the project:
a) Substantially impair an adopted
emergency response plan or
emergency evacuation plan?

b) Due to slope, prevailing winds, and
other factors, exacerbate wildfire risks,
and thereby expose project occupants
to pollutant concentrations from a
wildfire or the uncontrolled spread of a
wildfire?

c) Require the installation or maintenance
of associated infrastructure (such as
roads, fuel breaks, emergency water
sources, power lines or other utilities)
that may exacerbate fire risk or that
may result in temporary or ongoing
impacts to the environment?

d) Expose people or structures to
significant risks, including downslope or
downstream flooding or landslides as a
result of runoff, post-fire slop instability,
or drainage changes?

This section evaluates potential impacts related to wildfire risk; no portion of the project area is located within or near a State Responsibility Area (SRA) where Cal Fire is the primary emergency response agency responsible for fire suppression and prevention. a-d) Substantially impair an adopted emergency response plan or emergency evacuation plan? Due to slope, prevailing winds, and other factors, exacerbate wildfire risks, and thereby expose project occupants to pollutant concentrations from a wildfire or the uncontrolled spread of a wildfire? Require the installation or maintenance of associated infrastructure (such as roads, fuel breaks, emergency water sources, power lines or other utilities) that may exacerbate fire risk or that may result in temporary or ongoing impacts to the environment? Expose people or structures to significant risks, including downslope or downstream flooding or landslides as a result of runoff, post-fire slope instability, or drainage changes? (No Impact) The project site is not located in or near a SRA or lands classified as very high fire severity zones.

The project is located approximately 0.75 mile from the nearest SRA (Humboldt County 2019).

Therefore, the CEQA Guidelines Appendix G Checklist section for wildfire is not applicable to the project. No impact would result.

Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-59 Mandatory Findings of Significance
Potentially
Significant
Impact
Less-thanSignificant with
Mitigation
Incorporated
Less-thanSignificant
Impact
No
Impact
a) Does the project have the potential to
substantially degrade the quality of the
environment, substantially reduce the
habitat of a fish or wildlife species,
cause a fish or wildlife population to
drop below self-sustaining levels,
threaten to eliminate a plant or animal
community, substantially reduce the
number or restrict the range of a rare or
endangered plant or animal or
eliminate important examples of the
major periods of California history or
prehistory?

b) Does the project have impacts that are
individually limited, but cumulatively
considerable? (“Cumulatively
considerable” means that the
incremental effects of a project are
considerable when viewed in
connection with the effects of past
projects, the effects of other current
projects, and the effects of probable
future projects)?

c) Does the project have environmental
effects which would cause substantial
adverse effects on human beings,
either directly or indirectly?

a) Does the project have the potential to substantially degrade the quality of the environment, substantially reduce the habitat of a fish or wildlife species, cause a fish or wildlife population to drop below self-sustaining levels, threaten to eliminate a plant or animal community, substantially reduce the number or restrict the range of a rare or endangered plant or animal or eliminate important examples of the major periods of California history or prehistory? (Less Than Significant with Mitigation) As evaluated in this IS/MND, the project would not substantially degrade the quality of the environment; substantially reduce the habitat of a fish or wildlife species; cause a fish or wildlife population to drop below self-sustaining levels; threaten to eliminate a plant or animal community; reduce the number or restrict the range of an endangered, rare, or threatened species; or eliminate important examples of the major periods of California history or prehistory Mitigation measures are listed herein to reduce impacts related to Air Quality, Biological resources, Cultural Resources, Geology, Hydrology, and Transportation, and Tribal Cultural Resources. With implementation of the required mitigation measures, impacts would be less than significant. b) Does the project have impacts that are individually limited, but cumulatively considerable? (“Cumulatively considerable” means that the incremental effects of a project are considerable when viewed in connection with the effects of past projects, Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 3-60 the effects of other current projects, and the effects of probable future projects)? (No Impact)
Cumulative impacts are defined as “two or more individual effects which, when considered together, are considerable or which compound or increase other environmental impacts” (CEQA Guidelines § 15355). Cumulative impacts can result from individually minor but collectively significant actions taking place over a period of time. Efforts to identify cumulative projects included contact with the City of Fortuna and review of appropriate local agency project lists and capital improvement plans.

Based on such efforts, no additional projects were identified that would need to be considered for cumulative impacts. Therefore, no cumulative impact would result. c) Does the project have environmental effects which would cause substantial adverse effects on human beings, either directly or indirectly? (Less Than Significant) The project has been planned and designed to avoid significant environmental impacts. As discussed in the analysis throughout Section 3 of this IS/MND, the project would not have environmental effects that would cause substantial adverse direct or indirect effects on human beings. The impact would be less than significant.

Draft Document – For Discussion Only – Final Version May Differ From Draft Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 4-1 References
Bay Area Air Quality Management District (BAAQMD). 2017. California Environmental Quality Act Air Quality Guidelines.

California Department of Conservation (DOC). 2019. Farmland Mapping & Monitoring Program.

County Data. Available at: https://www.conservation.ca.gov/dlrp/fmmp Accessed on December 4, 2019.

California Department of Conservation (DOC). 2019b. EQ Zapp: California Earthquake Hazards Zone Application Web Mapping Tool. Available online:
https://maps.conservation.ca.gov/cgs/EQZApp/app/ Accessed on December 5, 2019.

California Department of Toxic Substances Control. 2019. EnviroStor database. Accessed on December 5, 2019.

California Department of Transportation (Caltrans). 2019. State Scenic Highway List. Available online: https://dot.ca.gov/-/media/dot-media/programs/design/documents/2017- 03desigandeligible-a11y.xlsx
California Environmental Protection Agency (CalEPA). 2019. Cortese List Data Resources.

Available online: https://calepa.ca.gov/wp-content/uploads/sites/6/2016/10/SiteCleanupCorteseList-CDOCAOList.xlsx City of Fortuna. 2010. General Plan.

City of Fortuna. 2018. 2017 Annual Report.

DZC Archaeology & Cultural Resource Management (DZC). 2019. Historic Property Identification Report for the City of Fortuna Wastewater Treatment and Effluent Percolation System Upgrade Project, Humboldt County, California. Prepared for the City of Fortuna, CA.

GHD. 2019a. Wastewater Treatment and Effluent Percolation System Upgrade Project Biological Resources Report. Prepared for the City of Fortuna.

GHD. 2019b. Soil and Groundwater Subsurface Investigation Report. Prepared for the City of Fortuna.

Humboldt County. 2015. Emergency Operations Plan, Humboldt Operational Area. Humboldt County, CA https://humboldtgov.org/DocumentCenter/View/51861/Humboldt-CountyEmergency-Operations-Plan-2015 Humboldt County. 2014. Eel River Area Local Coastal Plan.

Humboldt County. 2017. Humboldt County General Plan.

Humboldt County Planning and Building Department (Humboldt PBD). 2015. Liquefaction Hazard Zones: Humboldt County, California, 2015. Humboldt County Planning and Building Department. Available at: https://purl.stanford.edu/nk595pg0743 Natural Resources Conservation Service. 2019 Web Soil Survey, National Cooperative Soil Survey.

Available at https://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx Accessed on December 24, 2019
State Water Resources Control Board. 2019. GeoTracker web database. Available online:
https://geotracker.waterboards.ca.gov/ Accessed on December 5, 2019.

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Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 5-1 Report Preparers
City of Fortuna
Merritt Perry, City Manager
Brendan Byrd, Deputy City Engineer
GHD
Andrea Hilton, Environmental Planner
Brian Heaton, Environmental Planner
Kristine Gaspar, Senior Environmental Planner
Marlys Jeane, Environmental Planner
Misha Schwarz, Senior Scientist
Elizabeth Meisman, Wildlife Biologist
Sub-consultants
DZC Archaeology & Cultural Resource Management
Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND | Page 5-2 This page is intentionally left blank
P a c i f i c O c e a n H u m b o l d t
B a y
Eureka
Fortuna
Rio Dell
E e l R i v e r
254
255
1 211
36 101
FIGURE 1
0 1 2 3 4
Miles
Project No.

Revision No. -
11146364
Date Nov 2019
City of Fortuna Wastewater Treatment and Effluent
Percolation System Upgrade Project
Map Projection: Lambert Conformal Conic
Horizontal Datum: North American 1983
Grid: NAD 1983 StatePlane California I FIPS 0401 Feet
Paper Size ANSI A
Data source: Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community Sources: Esri, USGS, NOAA. Created by: jclark2
N:\US\Eureka\Projects\111\11146364 Fortuna-WW Plan Landowner\08- GIS\Maps\Deliverables\BRR\11146364_001_Vicinity_RevB.mxd Print date: 05 Dec 2019 - 10:58
Legend
Project Location
Highway
Major Road
Vicinity Map
101
101
Fortuna
Willow
Creek
Garberville
AArrccaattaa
Eureka
Arcata
McKinleyville
101
96 299
H u m b o l d t
C o u n t y
Draft Document – For Discussion Only – Final Version May Differ From Draft Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND This page is intentionally left blank
Potential Drill Pit
Mid-Point
(Contingency)
Drill Pit
(Contingency B)
Site Access
Infiltration
Area
Drill Pit
(Option A)
Pipe Staging
Site Access
WWTP Upgrades
FIGURE 2
0 370 740 1,110 1,480
Feet
Project No.

Revision No. -
11146364
Date Jan 2020
City of Fortuna Wastewater Treatment and Effluent
Percolation System Upgrade Project
Map Projection: Lambert Conformal Conic
Horizontal Datum: North American 1983
Grid: NAD 1983 StatePlane California I FIPS 0401 Feet
Paper Size ANSI A
N:\US\Eureka\Projects\111\11146364 Fortuna-WW Plan Landowner\08- Data source: Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community. Created by: jclark2 GIS\Maps\Deliverables\CEQA\11146364_003_AgSoils_RevA.mxd Print date: 22 Jan 2020 - 09:27
Legend
Project Study Boundary
Staging and Stockpiling
Area
Alternate Access
Potential Underground
Pipe Pathway
Western Site Access
Existing Unimproved
Road
New Road
Web Soil Survey Farmland
Classification
Not prime farmland
Prime farmland if
irrigated
Prime Agricultural Soils
Draft Document – For Discussion Only – Final Version May Differ From Draft Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND This page is intentionally
Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND Appendices
Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND This page is intentionally left blank
Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND Appendix A
Air Quality Modeling Results
Wastewater Treatment and Effluent Percolation System Upgrade Project – Administrative Draft IS/Proposed MND tblConstructionPhase PhaseEndDate 6/28/2024 6/10/2024
tblConstructionPhase NumDays 20.00 15.00
tblConstructionPhase NumDays 230.00 9.00
tblConstructionPhase NumDays 20.00 6.00
tblConstructionPhase NumDays 10.00 14.00
Table Name Column Name Default Value New Value

1.3 User Entered Comments & Non-Default Data
Project Characteristics - Construction only run
Land Use - User defined as waste water treatment plant; units in acres; 400 sq ft of that is buildings Construction Phase - Project-specific durations
CO2 Intensity
(lb/MWhr)
641.35 CH4 Intensity
(lb/MWhr)

0.029 N2O Intensity
(lb/MWhr)

0.006
93 Climate Zone 1 Operational Year 2025
Utility Company Pacific Gas & Electric Company

1.2 Other Project Characteristics
Urbanization Rural Wind Speed (m/s) 2.2 Precipitation Freq (Days) Floor Surface Area Population
General Light Industry 220.00 1000sqft 5.05 220,000.00 0

1.0 Project Characteristics

1.1 Land Usage
Land Uses Size Metric Lot Acreage
CalEEMod Version: CalEEMod.2016.3.2

Page 1 of 1 ends

Fortuna City CouncilSeptember 21, 2026

Fortuna City Council
September 21, 2026