Agenda packet — Sutter Creek City Council, March 17, 2025 (part 3 of 4)

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Figure 1: ARSA Storage and Disposal System Flow Diagram Amador Regional Sanitation Authority (ARSA)
Revised Water Balance Update
February 2025

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On August 14, 2024, the SWRCB issued a Water Code Section 13267 Order to requiring ARSA, MCSP, and the City to verify their abilities and capacities to adequately convey, treat, and dispose of the wastewater generated by their own respective collection systems without impacting beneficial uses. ARSA, the City, and Portlock submitted the water balance by December 13, 2024, in accordance with the Water Code Section 13267 Order.

On February 3, 2025, the SWRCB issued a comment letter to ARSA, the City, and Portlock International requiring revisions to the water balance. This updated TM incorporates updates made in response to the February 3, 2025 review letter. The comments and their corresponding updated sections of this TM are summarized in Table 1 below.

Table 1: Summary of Revisions Pursuant to SWRCB Review Letter from February 3, 2025 Required Action Items Revised TM Section
A. Rainfall Data – Redistribute to reflect average-year rainfall patterns. Current Flow Conditions Climatological Data
B. City of Sutter Creek Inflow & Infiltration – Provide additional supporting information or exclude Future Projected Flows & Population C. City of Ione Title 22 Engineering Report – Provide additional supporting information Attachment D
D. Castle Oaks Golf Course Overflow of Lake I – Cease overflow discharge and update water balance accordingly Attachment D E. Operational Decisions not in WDRs – Exclude assumptions such as unpermitted discharge to surface water
Disposal Facilities Characterization –
Bower’s Ranch
F. Submit Spreadsheets and Data Attachment F & Excel Spreadsheet 269
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WWTP Flow & Population Data
This section documents the existing wastewater flows to the Sutter Creek WWTP, and wastewater flows over the next 5 years based on population growth as required by the Water Code Section 13267 Order item 1.A. Daily flow data from January 2017 through September 2024 for the Sutter Creek WWTP and monthly status reports from January 2016 through July 2024 for ARSA facilities were provided by Sutter Creek and ARSA Staff. Population data was sourced from the California Department of Finance. Population and flow data is included as Attachment A for reference.

Current Flow Conditions
An analysis of the daily flow data indicates the Average Dry Weather Flow (ADWF) (average of flows from July through September) from 2017 through 2024 was typically 0.31 MGD.

Table 2: Sutter Creek WWTP ADWFs from 2017 Through 2024 Year ADWF
(MGD
2017 0.291
2018 0.305
2019 0.342
2020 0.269
2021 0.326
2022 0.327
2023 0.328
2024 0.318
Average 0.313
Throughout the months of December through April, Sutter Creek WWTP effluent flows can increase from infiltration and inflow (I/I) due to significant rainfall events. Precipitation data from the National Oceanic and Atmospheric Administration Sutter Hill CDF station was collected and compared to the Sutter Creek WWTP flow data. Data shown in Figure 2 indicates that once surface soils become saturated from initial rainfall, I/I increases significantly during subsequent rainfall events further into the periods of December through April. 270
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Figure 2: Sutter Creek WWTP Effluent Flows and Rainfall 0 1
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Total Monthly Precipitation (inch) Total Monthly Flows (Mgal/month) Total Monthly ADWF (Mgal/month) 271
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To benchmark the Sutter Creek WWTP I/I, the historical wet years of 2016/17 and 2022/23 were compared to the estimated 1-in-100 Return Period (RP100) total wastewater flows. In 2016/17 water year (WY) there were 14.2 inches of precipitation from October through December before

15.1 inches of precipitation occurred in January when the peak flow of 94.8 Ac-ft also occurred.

In the 2022/23 WY, there were 11.8 inches of precipitation in October through December and only

0.39” in Jan and the peak flow for the month of Jan resulted in 86.2 Ac-ft/month.

Due to the estimation of the I/I being a function of monthly precipitation, the first calibration step is adjustment of the monthly distribution of RP100 precipitation to match the 2016/17 WY rainfall patterns as described in the Climatological Data section. The climatological adjustment results in the I/I decreasing for November, March and May because the rainfall distribution for 2016/17 WY was much lower for those months. The calibrated I/I is also higher in October, December, January and April than compared to the average year because of their higher adjusted rainfall distribution.

Next, to bring the modeled RP100 flows within range of the 2016/17 and 2022/23 flows, a 25% increase in I/I from December through April was applied. This results in a January modeled peak flow of 87.4 Ac-ft which is within 8% of the 2016/17 WY peak flow. Due to the high variance and potential errors in estimating the precipitation vs I/I data, this 25% multiplier during the wet months can be considered a calibration of the modeled RP100 flows to be consistent with historical data.

As mentioned by Action Item A of the February 3, 2025, SWRCB review letter, the rainfall for January/February 2017 was much heavier than typical distribution and it may be more representative to distribute the rainfall and flow more evenly over the wet season. To evaluate the effects of rainfall distribution, RP100 rainfall and effluent flows will also be distributed based on average-year distribution and include the 25% I/I increase factor for December through April.

The uncalibrated and calibrated RP100 flows and their comparative 2016/17 and 2022/23 Sutter Creek WWTP effluent flows are illustrated in Figure 3 for reference.

Figure 3: Calibration of Sutter Creek WWTP I/I for RP100 Conditions

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Wet Year - 2016/17 Water Year Wet Year - 2022/23 Water Year RP100 Water Year - Uncalibrated RP100 Water Year - Climate Calibration Only RP100 Water Year - Calibrated, 25% Factor Applied R100 Water Year - 25% Factor Applied, Avg Yr Rain Distribution 272
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Future Projected Flows & Population
In recent years the City of Sutter Creek has taken steps to reduce the I/I from the Sutter Creek WWTP collection system which included sealing of manholes within and adjacent to creek beds.

Future I/I reduction efforts are expected to continue to be taken by the City of Sutter Creek, as documented in the Draft 2023 Sutter Creek WWTP I/I Analysis Update Technical Memorandum from Carollo Engineers provided as Attachment B for reference. This analysis involved flow monitoring of the collection system and modeling of the effects of I/I mitigation efforts on peak hour influent flows to the WWTP.

I/I mitigation efforts considered included manhole rehabilitation, sewer main rehabilitation or replacement and lateral rehabilitation that were recommended for sewer shed areas that have the highest I/I rates per foot of sewer pipe, which are 18% of the collection system by length. The Carollo Draft Technical Memorandum estimated the I/I reduction projects in the targeted 18% of the collection system may result in the peak hour influent flow to be reduced between 30% to 65%. However, the results of I/I reduction projects may have a more modest effect upon the peak month flows because, unlike during a peak hour event, over a peak month there may be enough time for infiltration to occur at a low rate that may still result an increased monthly influent volume.

In the prior water balance evaluation a peak month flow reduction of 5.4% was estimated for future flows, however the flow reduction has been removed due to the uncertainty of the effectiveness of the I/I reduction projects. To justify reducing the anticipated future flows (in future technical reports/analyses), the City may provide additional supporting information for the I/I reduction projects. The City may also complete additional flow monitoring after implementing the I/I reduction projects to substantiate effects on WWTP flows.

Population data provided by ARSA is sourced from the California Department of Finance population projections, which estimates in the next five years, by 2029, the population of Amador County will increase 2.17 percent.1 The population of Sutter Creek, Martell, and Amador City are expected to increase proportionally to the projected Amador County population growth rate. The projected increases in population and flow are summarized in Table 3. ADWFs in 2029 are anticipated to reach 0.319 MGD, which is the basis of ADWF for Future Water Balance Results.

Table 3: Future Sutter Creek WWTP Flow Projections
Based on Population Growth and I/I Reduction Projects
Year ADWF
(MGD)
Model Peak
Month Flow
(MGD)
2024 0.313 2.819
2029 0.319 2.687
Total Change +2.17% -4.7%
1 CA Department of Finance Population Projections P-2A, November 2024: Projections | Department of Finance
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Climatological Data
This section discusses the climatological data sources and their characteristics that were used for uncalibrated and calibrated water balance calculations. Statistical depth-duration-frequency data for the RP100 frequency at 1-Year duration are referenced from the California Department of Water Resources, Ione station (station number B00 4283 00).2 Precipitation for the RP100 WY totals 41.11 inches based on the Ione station. Monthly precipitation patterns and totals are based on the Western Regional Climate Center Comparative Tables for Ione.3 Average-year precipitation totals approximately 21.41 inches annually, resulting in a RP100 to average-year ratio of 1.92.

During initial water balance calculations, it became apparent that precipitation patterns during RP100 WYs did not follow the same trend as the monthly precipitation distribution during average years. The most recent historical data of a WY similar to the RP100 is the 2016/17 WY which saw 105% of the RP100 total precipitation (43.37 inches) with 15.1 inches occurring in January 2017 alone. To better fit the historically significant 2016/17 data, the RP100 precipitation pattern was adjusted to fit the monthly pattern of the 2016/17 WY, but with reduced amounts to match the statistical RP100 precipitation of 41.11 inches. The adjusted data is illustrated in Figure 4.

The adjustment of the distribution of monthly precipitation for the RP100 WY is a calibration element, as mentioned in the Water Balance Results section.

A water balance using RP100 total precipitation distributed based on the average year (“Uncalibrated RP100”) has also been included in the discussion of the Water Balance Results to address Required Action Item A from the SWRCB review letter. 2 Ione Rainfall Depth Duration Frequency Table, California Department of Water Resources, November 2024: DDF Ione CA
3 Western Regional Climate Center Precipitation Comparative Tables, November 2024: WRCC: Precipitation Comparative Table (dri.edu)
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Figure 4: Calibration of RP100 Monthly Precipitation Patterns to Match 2016/17 Water Year Pan evaporation data stations within the project vicinity are limited, therefore the Camp Pardee station was the closest selected station from the Western Regional Climate Center Pan Evaporation Comparative Tables (located within approximately 9 miles from Ione and 10 miles from Sutter Creek).4 Pan evaporation from the Camp Pardee station totaled 57.88 inches per year, and a typical pan coefficient of 0.75 was applied to the monthly pan evaporation data to estimate the effective lake evaporation from Henderson and Preston Reservoirs and the Preston Forebay. Additionally, a weather correction factor reduction of 25% was applied to the months of November through March during the RP100 WY to account for reduction in evaporation during a wet year wet season.

Reference evapotranspiration (Eto) data were acquired from the California Irrigation Management Information System (CIMIS) for the Shenandoah station 81, which is within 6.5 miles of Sutter Creek, and 9.5 miles of Ione and located within the Sierra Foothills, CIMIS Zone 13. The Shenandoah station reported an annual Eto total of 49.4 inches. Crop coefficients (Kc) consistent with pasture grasses for CIMIS Zone 13 were applied to the reference Eto of CIMIS station 81 to calculate crop evapotranspiration (Etc) rates at the LAAs.5 Wet year Kc values were used to calculate the RP100 WY Etc, and typical year Kc values were used to calculate average year Etc values. The difference between the monthly rainfall depth and the Etc resulted in the agronomic crop irrigation demand values. Rainfall efficiency is conservatively estimated at 100%, meaning all precipitation over the LAAs reaches the ground surface and is not evaporated to atmosphere.

Finally, the irrigation efficiency is estimated at 85% which approximates a highly efficient irrigation system minimizing potential for overestimation of irrigation demands. 4 Western Regional Climate Center Pan Evaporation Comparative Tables, November 2024: WRCC: Pan Evap Comparative Table (dri.edu)
5 California Crop and Soil Evapotranspiration, ITRC Report 03-001, January 2003, www.itrc.org/reports/pdf/californiacrop.pdf

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Uncalibrated RP100 Precipitation WY 2016/17 Precipitation Calibrated RP100 Precipitation 275
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A summary of the climatological data used for the uncalibrated and calibrated water balance calculations is provided in Table 4: Estimated Climatological Parameters for Water Balance Calculations.
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Table 4: Estimated Climatological Parameters for Water Balance Calculations Climatological Parameters Units Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep WY Total Precipitation – Avg. Year Inch 1.20 3.47 3.50 3.83 3.10 3.01 2.06 0.47 0.15 0.10 0.19 0.33 21.41 Precipitation – Uncalibrated RP100 Inch 2.30 6.66 6.72 7.35 5.95 5.78 3.96 0.90 0.29 0.19 0.36 0.63 41.11 Precipitation - Calibrated RP100 Inch 5.98 2.42 5.10 14.28 4.48 3.21 3.88 0.50 1.21 0.00 0.02 0.02 41.11 Effective Lake Evap. – Avg. Year Inch 2.83 1.05 0.54 0.54 0.84 1.74 3.14 5.28 7.07 8.38 7.13 4.88 43.41 Effective Lake Evap. – RP100 Inch 2.83 0.79 0.41 0.41 0.63 1.31 3.14 5.28 7.07 8.38 7.13 4.88 42.23 Reverence Evapotranspiration – CIMIS
Station 81 Inch 3.60 1.75 1.21 1.19 1.83 3.10 4.42 5.67 6.88 7.56 7.02 5.17 49.40 Pasture Grass Agronomic Application –
Avg. Year Ft/Ac 0.05 0.00 0.00 0.00 0.00 0.00 0.09 0.46 0.63 0.69 0.64 0.41 2.96 Pasture Grass Agronomic Application –
Uncalibrated RP100 Ft/Ac 0.09 0.00 0.00 0.00 0.00 0.00 0.06 0.54 0.69 0.72 0.65 0.45 3.21 Pasture Grass Agronomic Application –
Calibrated RP100 Ft/Ac 0.00 0.00 0.00 0.00 0.00 0.17 0.07 0.58 0.60 0.74 0.69 0.51 3.36 277
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Storage Facilities Characterization
This section describes the Henderson Reservoir, Preston Forebay and the Preston Reservoir, which are the ARSA system’s effluent storage facilities as illustrated in the Figure 1 flow diagram.

Detailed information including topographical survey data from November 7, 2008, for Henderson Reservoir, the stage-storage curve data (for Henderson and Preston Reservoirs) and dam embankment data sheets for the reservoirs are provided in Attachment C.

Henderson Reservoir
Henderson Reservoir is reported to have a variable usable storage volume with a minimum 2 feet of freeboard from spillway ranging from 27.5 ac-ft to 392.8 ac-ft, and surface area (8.5 ac to 29 ac) based on the reservoir being at a minimum pool (approximately 5 ft stage) at the end of the dry season and at a maximum at the end of the wet season. The reservoir is described as providing seasonal storage but never to be empty. Therefore, an initial volume in any scenario was assumed to be 27.5 ac-ft and the goal of the water balance is to reach 27.5 ac-ft at the end of the dry season.

Percolation and evaporation rates are functions of the water surface area of the reservoirs; however the percolation rates are uncertain and have not been recently studied. Reservoir surface area was back-calculated from the month-to-month accumulated storage volume in the reservoir and then multiplied by the evaporation or percolation rate. The reservoir also accumulates precipitation throughout the entire acreage of 29 acres. Sutter Creek is diverted around the reservoir but a catchment area of 4.3 acres is assumed to add runoff to the reservoir with a very conservative runoff coefficient of 1.

Since Henderson Reservoir is the first reservoir in the system, the operational strategy taken in the water balance is to retain as much effluent and precipitation runoff in the reservoir throughout the wet season until full, at which point effluent would be sent from Henderson to Preston Reservoir.

Preston Forebay
The disposal capacity of the Preston Forebay is calculated as if it were only a pass-through system as the water flows through the reservoir and it maintains a constant water surface elevation and surface area. The percolation rate is reportedly zero leaving only evaporation as a means of disposal. The surface area is 2 acres with no discernible runoff catchment area.

Preston Reservoir
Preston Reservoir is reported to have a variable usable storage volume with a minimum 2 feet of freeboard from spillway ranging from 0 ac-ft to 235 ac-ft, and surface area (0 ac to 18 ac) based on the reservoir often being empty at the end of the dry season. Therefore, the initial volume in water balance scenarios was assumed to be 0 ac-ft and the goal of the water balance is to reach 0 ac-ft storage at the end of the dry season.
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Similar to the Henderson Reservoir calculations, percolation and evaporation rates are a function of the water surface area of the reservoir, however the percolation rates are assumed to be negligible due to a lack of percolation studies. Reservoir surface area was back-calculated from the month-to-month accumulated storage volume in the reservoir and then multiplied by the evaporation rate. The reservoir also accumulates precipitation throughout the entire acreage of 18 acres. Preston Reservoir also has a catchment area of 14 acres that adds runoff to the reservoir with a very conservative runoff coefficient of 1.

Since Preston Reservoir is the final reservoir in the system, the operational strategy taken in the water balance is to receive any excess effluent and precipitation runoff from upstream components when Henderson Reservoir does not have available storage capacity. As a result, Preston Reservoir quickly receives large effluent volumes later in the wet season but does not reach its maximum capacity in any evaluated scenario.
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Disposal Facilities Characterization
This section describes the Bower’s Ranch, Hoskin’s Ranch and the COGC, which are the ARSA system’s effluent disposal facilities as illustrated in the Figure 1 flow diagram. Disposal capacity of each site is evaluated based on the Climatological Data section. Although Noble Ranch is described, it is not currently in use as a LAA.

Bower’s Ranch
ARSA has a 40 acre land application (flood irrigation) disposal easement upon Bower’s Ranch.

The disposal facility was recently expanded from 60% constructed (24 acres) to fully utilizing the 40 acre site. As Bower’s Ranch is the first LAA in the ARSA system, it is often fully utilized to take almost all of the Sutter Creek WWTP effluent for the months of June through October. Due to the site topography, any tailwater from the site is received by Henderson Reservoir and there is little to no risk of tailwater migrating to other properties. The site primarily consists of pasture grass that is used for cattle grazing.

As identified by Required Action Item E from the SWRCB review letter dated February 3, 2025, the water balance must include only facilities operated in compliance with WDRs and applicable regulations. Due to various compliance issues that the SWRCB asserts to exist with the current operation of Bower’s Ranch, it has been removed from utilization in the water balance.

Hoskin’s Ranch
ARSA has a 60 ac LAA at Hoskin’s Ranch that is used for spray land application. The disposal facility was recently expanded from only 40% constructed (24 acres) to 60% constructed (36 acres). This LAA is primarily used for pasture grasses and for grazing cattle. Application rates are carefully monitored by ARSA Staff to prevent any overspray and to maintain but not exceed agronomic application rates.

Noble Ranch
Sutter Creek has an existing land application disposal easement for this site for 1,300 ac-ft/yr.

This facility is not yet constructed nor is the site in use. Therefore, this site was not characterized or evaluated for water balance calculations.

Castle Oaks Golf Course
Disinfected secondary effluent from the ARSA system is exported from Preston Reservoir to the COWRF for tertiary treatment and subsequent water recycling at the COGC. The COGC includes a total irrigable acreage of 130 acres and contains nine lakes with only one lake (Lake I) totaling

3.1 acres that is typically filled with recycled water during the irrigation season. Demands to be met by ARSA’s effluent include both the COGC irrigation demands and backwash flows at the COWRF which are necessary to maintain the COWRF system operation. The operation of the COWRF is detailed in Attachment D. COWRF influent flows total approximately 423.4 Ac-ft during 280
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the RP100 WY and 481.7 Ac-ft during the average year. The capacity evaluation of the COWRF and COGC was completed by West Yost Engineers, and their 2024 COGC Recycled Water Demands Technical Memorandum is included as Attachment E for further reference. Additionally, a cover letter has been prepared by West Yost in response to the SWRCB’s February 3, 2025, review letter and is included in Attachment D.
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Water Balance Results
This section discusses water balance calculations that were completed for uncalibrated current flow conditions, calibrated current flow conditions, and calibrated future flow conditions. All water balance calculations consist of evaluation of system operations during a RP100 WY followed by an average year WY.

As discussed in the WWTP Flow & Population Data section, calibration of the flow data included increasing the I/I volume by 25% from December through April to be consistent with 2016/17 and 2022/23 WY flow data. Calibration of precipitation in the Climatological Data involved adjusting the monthly distribution of RP100 annual precipitation based on 2016/17 WY precipitation data.

Another set of scenarios were also evaluated with RP100 annual precipitation distributed over more average-year conditions rather than the 2016/17 WY. The calibrations result in increased effluent reservoir storage volumes and increased flow I/I flow volumes. Calibrated future flow conditions account for the same I/I and climate calibrations and 2.17% population growth. As discussed in the Future Projected Flows & Population section, no I/I flow reduction has been included although the City of Sutter Creek will continue to pursue the I/I reduction projects and may provide additional information in the future to more precisely evaluate the flow effects.

The strategy of the water balance calculations incorporates the following logic:
1) Fully meet all irrigation demands at the LAAs (Hoskin’s Ranch, and COGC) utilizing Sutter Creek WWTP effluent to the maximum agronomic rate for each given month. 2) Any shortfall of irrigation demands (which is also an excess of LAA disposal capacity) would be made up by water supplies other than the Sutter Creek WWTP effluent. It is assumed water supplying unmet irrigation demands are conveyed through the ARSA system, and are accounted for in monthly inflows and storage volumes. These are figurative estimates for water balance calculation purposes, and no specific water supply is identified to meet these demands.
3) Henderson Reservoir is assumed to maintain a minimum dead pool of 27.5 Ac-ft at 5 ft stage, whereas Preston Reservoir is allowed to reach 0 Ac-ft storage (empty). 4) Any excess of Sutter Creek WWTP effluent or precipitation / runoff not used to meet irrigation demands is stored in Henderson Reservoir first and then, once it reaches full capacity of 392.8 Ac-ft at 2 ft freeboard, any excess volume is sent to Preston Reservoir.

Runoff and precipitation within Henderson Reservoir or its catchment area is retained in it. All other runoff and precipitation in the system in excess of monthly irrigation demand is retained in Preston Reservoir. The resulting final storage volumes for the month are then carried over as the beginning storage volume for the following month. 282
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Water balance calculations completed for all scenarios indicate the ARSA system in combination with the COWRF and COGC can adequately contain and dispose of all Sutter Creek WWTP effluent, precipitation, and runoff for the RP100 WY without violation of storage capacity or agronomic application rates. When RP100 WY rainfall occurs on an average year distribution, the disposal capacity is decreased by approximately 0.4 Ac-ft during the irrigation season due to higher precipitation during the irrigation season which decreases the agronomic irrigation demands. However, the maximum storage required during the WY is decreased by 5.9 Ac-ft if the RP100 rainfall is distributed like an average WY.

Unlike the previous December 2024 water balance calculation, these results indicate there is only

12.5 to 13.0 Ac-ft of surplus disposal capacity (unmet irrigation demands) in the disposal system.

Capacity for additional flows from other dischargers appears to be limited based on these results.

These water balance calculations do not include discharges from MCSP nor any future flows from City of Ione arising from approved housing developments exceeding existing secondary plant capacity. The remaining capacity of the COGC to accommodate flows from either of these sources is limited. The MCSP would need to utilize their sprayfields as a component of their disposal strategy, and City of Ione would need to develop additional disposal areas to address city growth. The COWRF accepting discharges from both MCSP and the City of Ione in the future is likely infeasible without large-scale expansion of the COWRF, and expansion of the COGC or development of additional LAAs.

The overall water balance results for each scenario are summarized in Table 5. Detailed water balance calculations are provided in Attachment F for further reference. 283
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Table 5: Summary of Water Balance Calculation Results
Row
Number Row Calculations
Parameters
Water Balance Scenario Results
Scenario 1 Scenario 2a Scenario 2b Scenario 3a Scenario 3b Uncalibrated Current Flows Calibrated Current Flows
Avg-WY Rain Distribution
Calibrated Current Flows
2016/17-WY Rain Distribution
Calibrated Future Flows
Avg-WY Rain Distribution
Calibrated Future Flows
2016/17-WY Rain Distribution
Climate Conditions RP100
(Year 1)
Avg Year
(Year 2)
RP100
(Year 1)
Avg Year
(Year 2)
RP100
(Year 1)
Avg Year
(Year 2)
RP100
(Year 1)
Avg Year
(Year 2)
RP100
(Year 1)
Avg Year
(Year 2)
Inflow Results
A -- WWTP Effluent (Ac-ft) 503.2 442.7 528.9 457.4 529.8 457.4 536.5 465.0 537.4 465.0 B -- Precipitation and Runoff (Ac-ft) 230.6 120.1 230.6 120.1 230.6 120.1 230.6 120.1 230.6 120.1 Storage Facilities Results
C -- Henderson Reservoir Max Storage Volume (Ac-ft) 392.8 283.6 392.8 296.1 392.8 296.1 392.8 300.4 392.8 300.4 D -- Preston Reservoir Max Storage Volume (Ac-ft) 139.9 135.1 165.0 141.0 170.9 140.5 169.3 147.3 175.2 154.4 E -- Henderson Reservoir Evaporation (Ac-ft) 73.1 57.4 73.2 59.3 73.6 59.3 73.5 60.2 73.8 60.2 F -- Preston Forebay Evaporation (Ac-ft) 6.6 6.4 6.6 7.2 6.6 7.2 6.6 7.2 6.6 7.2 G -- Preston Reservoir Evaporation (Ac-ft) 40.2 36.8 44.3 43.3 45.4 43.2 45.0 45.0 46.1 46.9 Disposal Results
H -- Bower’s Ranch Irrigation Demands (Ac-ft) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 I -- Hoskin’s Ranch Irrigation Demands (Ac-ft) 115.5 106.7 115.5 106.7 115.5 106.7 115.5 106.7 115.5 106.7 J -- COWRF & COGC Irrigation Demands (Ac-ft) 423.4 481.7 423.4 481.7 423.4 481.7 423.4 481.7 423.4 481.7 K -- Unmet Irrigation Demands (Ac-ft) 0.0 51.1 0.0 24.2 0.0 24.7 0.0 12.5 0.0 13.0 Overall Calculation Results
L (A+B) Total Inflows Excluding Unmet Irrigation Demands (Ac-ft) 733.9 562.8 759.5 577.5 760.4 577.5 767.1 585.1 768.0 585.1 M (A+B+K) Total Inflows Including Unmet Irrigation Demands (Ac-ft) 733.9 613.9 759.5 601.8 760.4 602.2 767.1 597.7 768.0 598.1 N (E+F+G+ I+J) Total Outflows (Ac-ft) 658.8 689.0 663.1 698.2 664.5 698.1 664.0 700.8 665.4 700.7 O (N – L), or K Unmet Irrigation Demands (Ac-ft) 0.0 51.1 0.0 24.2 0.0 24.7 0.0 12.5 0.0 13.0 P (C+D), or as shown (1) Maximum Storage Volume Required (Ac-ft) 532.7 402.6 557.8 437.1 563.7 436.6 562.1 447.7 568.0 447.2 Q (627.8 Ac-ft – P) Unutilized Storage Capacity at Peak Storage (Ac-ft) 95.1 223.2 70.0 190.7 64.1 191.2 65.7 180.1 59.8 180.6 (1) The peak month storage volumes for Henderson and Preston Reservoirs may be in different months than the overall system’s peak storage month, resulting in minor discrepancies of 2.4 to 2.9 Ac-ft between Row N values and (D+E) calculations. Where discrepancies occur, Row N displays overall peak storage month volumes from water balance calculations. 284
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ATTACHMENT A
Amador Regional Sanitation Agency
2024 Individual Water Balance Update
Sutter Creek WWTP Population and Flow Data
286
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Section 13, Item J.

CA Department of Finance
Population Projection by County
Report P-2A: Total Estimated and Projected Population for California and Counties: July 1, 2020 to 2070 Estimates Projections
FIPS Geography 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 20306000 CALIFORNIA 39,541,722 39,246,702 39,146,273 39,109,070 39,119,734 39,155,670 39,243,572 39,340,965 39,451,269 39,568,558 39,694,9606001 ALAMEDA 1,680,487 1,657,465 1,649,975 1,656,037 1,654,334 1,654,555 1,660,187 1,666,430 1,673,310 1,680,926 1,689,2256003 ALPINE 1,202 1,180 1,175 1,165 1,163 1,163 1,165 1,170 1,174 1,172 1,1766005 AMADOR 40,440 40,262 40,105 40,122 40,198 40,298 40,429 40,615 40,828 41,070 41,327

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288
Section 13, Item J.

ARSA Facilities Monthly Status Reports - Provided by ARSA Staff Date Month
Sutter
Creek
WWTP
(mg)
Sutter
Creek
WWTP
(ac ft)
Bowers
Irrigation
(mg)
Bowers
Volume
irrigated
(ac ft)
Henderson
Freeboard
Volume in
Henderson (af)
Capacity
Remaining in
Henderson (af)
Henderson
Outflow (mg)
Henderson
outflow (ac ft)
Hoskins
Irrigation
(mg)
Hoskins
Volume
irrigated (ac
ft)
Mule Creek
Inflow (mg)
Mule Creek
Inflow (ac
ft)
Preston
Freeboard
Volume in
Preston (af)
Capacity Remaining
in Preston (ac ft)
Outflow to
Ione (mg)
Outflow to
Ione (ac ft)
TOTAL Ac Ft
of Effluent in the
system
TOTAL
Remaining
Capacity for
Winter (ac
ft)
TOTAL

USED FOR

IRRIGATI
ON (ac ft)
2016
1/31/2016 Jan 19.0 58.3 0.0 0.0 12'1" 155.8 237.2 12.4 38.1 0.0 0.0 0.0 0.0 11'4" 94.7 140.3 3.9 12.0 250.47 377.5 12.0 2/29/2016 Feb 10.7 32.8 0.0 0.0 10'9' 180.9 212.1 17.8 54.6 0.0 0.0 0.0 0.0 8'7" 128.4 106.6 4.0 12.3 309.27 318.7 12.3 3/31/2016 Mar 17.7 54.3 0.0 0.0 8'7" 225.7 167.3 15.1 46.3 0.0 0.0 0.0 0.0 5'7" 171.0 64.0 3.4 10.4 396.64 231.4 10.4 4/30/2016 Apr 10.7 32.8 0.0 0.0 8'5" 229.3 163.7 13.7 42.0 0.0 0.0 0.0 0.0 5'7" 171.0 64.0 9.1 27.9 400.29 227.7 27.9 5/31/2016 May 9.3 28.5 0.0 0.0 9'9" 201.0 192.0 23.0 70.6 0.0 0.0 0.0 0.0 7'7" 141.9 93.1 27.3 83.8 342.85 285.2 83.8 6/30/2016 Jun 8.3 25.5 2.9 8.9 14'4" 117.6 275.4 32.2 98.8 2.2 6.8 0.0 0.0 9'8" 114.5 120.5 36.0 110.5 232.06 395.9 126.1 7/31/2016 Jul 9.0 27.6 9.0 27.6 20'1" 43.8 349.2 25.4 77.9 5.3 16.3 35.9 110.2 7'6" 143.1 91.9 40.9 125.5 186.84 441.2 169.4 8/31/2016 Aug 9.2 28.2 9.2 28.2 22'3" 24.9 368.1 8.7 26.7 3.2 9.8 32.9 101.0 8'3" 132.8 102.2 44.1 135.3 157.68 470.3 173.4 9/30/2016 Sep 8.3 25.5 6.3 19.3 25'8" 5.0 388.0 10.8 33.1 2.2 6.8 10.3 31.6 13'2" 75.1 159.9 37.5 115.1 80.06 547.9 141.2 10/31/2016 Oct 11.0 33.8 2.5 7.7 23'2" 18.4 374.6 5.9 18.1 0.0 0.0 4.0 12.3 14'4" 63.8 171.2 6.4 19.6 82.18 545.8 27.3 11/30/2016 Nov 11.2 34.4 0.0 0.0 20'8" 38.2 354.8 5.3 16.3 0 0.0 0.0 0.0 14'2" 65.4 169.6 0.0 0.0 103.6 524.4 0.0 12/31/2016 Dec 16.5 50.6 0.0 0.0 16'8" 83.5 309.5 10.4 31.9 0.0 0.0 0.0 0.0 11'6" 92.8 142.2 0.0 0.0 176.32 451.7 0.0 Total: 140.9 432.4 29.9 91.8 180.7 554.5 12.9 39.6 83.1 255.0 212.6 652.4 783.8 2017
1/31/2017 Jan 30.9 94.8 0.0 0.0 9'3" 211.4 181.6 10.7 32.8 0.0 0.0 0.0 0.0 6'8" 154.9 80.1 245.8 0.0 366.25 261.8 0.0 2/28/2017 Feb 26.5 81.3 0.0 0.0 4'1" 334.2 58.8 10.2 31.3 0.0 0.0 0.0 0.0 4'4" 190.6 44.4 136.3 0.0 524.72 103.3 0.0 3/31/2017 Mar 15.5 47.6 0.0 0.0 1'5" 408.4 43.6 14.1 43.3 0.0 0.0 0.0 0.0 1'5" 240.4 29.6 90.8 4.7 648.74 73.3 4.7 4/30/2017 Apr 16.1 49.4 0.0 0.0 1'6" 405.9 46.1 34.9 107.1 0.0 0.0 0.0 0.0 1'8" 235.9 34.1 104.6 18.2 641.82 80.2 18.2 5/31/2017 May 9.6 29.5 0.0 0.0 3'7" 347.5 45.5 38.0 116.6 2.7 8.3 0.0 0.0 1'2" 244.9 25.1 77.0 83.9 592.42 70.6 92.2 6/30/2017 Jun 8.9 27.3 8.0 24.6 6'7" 271.3 121.7 36.0 110.5 8.8 27.0 0.0 0.0 3'2" 209.8 25.2 77.3 111.2 481.07 146.9 162.8 7/31/2017 Jul 8.6 26.4 8.7 26.7 11' 176.1 216.9 35.0 107.4 10.7 32.8 0.0 0.0 6'11" 151.3 83.7 256.9 128.3 327.34 300.7 187.8 8/31/2017 Aug 8.8 27.0 8.7 26.7 13'9" 127.0 266.0 20.6 63.2 8.6 26.4 0.0 0.0 7'6" 143.1 91.9 282.0 37.3 270.02 358.0 90.4 9/30/2017 Sep 8.7 26.7 8.7 26.7 16'2" 90.3 302.7 18.3 56.2 11.9 36.5 0.0 0.0 6'10 152.5 82.5 253.2 0.0 242.81 385.2 63.2 10/31/2017 Oct 8.0 24.6 8.1 24.9 17'4" 74.8 318.2 13.8 42.4 9.4 28.8 0.0 0.0 9'7" 115.5 119.5 366.7 52.6 190.33 437.7 106.3 11/30/2017 Nov 11.5 35.3 0.9 2.8 14'10" 121.6 271.4 9.7 29.8 7.4 22.7 0.0 0.0 11'1" 97.5 137.5 422.0 83.5 219.1 408.9 109.0 12/31/2017 Dec 9.5 29.2 0.0 0.0 12'9" 143.9 249.1 0.0 6.3 19.3 0.0 0.0 10'6" 104.4 130.6 400.8 0.0 248.26 379.7 19.3 Total: 162.6 499.0 43.1 132.3 241.3 740.5 65.8 201.9 0.0 0.0 2713.5 519.7 853.9 2018
1/31/2018 Jan 13.6 41.7 0 0.0 9'7" 206.1 186.9 8.4 25.8 0 0.0 0 0.0 8'8" 128.4 106.6 0.0 0.0 334.5 293.5 0.0 2/28/2018 Feb 8.7 26.7 0 0.0 7'10" 240.4 152.6 5.1 15.7 0 0.0 0 0.0 8'3" 133.9 101.1 0.0 0.0 374.3 253.7 0.0 3/31/2018 Mar 22.1 67.8 0 0.0 4'1" 332.9 60.1 8.00 24.6 0 0.0 0 0.0 5'11" 164.1 70.9 0.0 0.0 497 131.0 0.0 4/30/2018 Apr 14.1 43.3 0 0.0 3'9" 342.6 50.4 23.8 73.0 6.0 18.4 0 0.0 3'3" 200.9 34.1 1.2 3.7 543.5 84.5 22.1 5/31/2018 May 9.3 28.5 0 0.0 3'10" 340.6 52.4 16.9 51.9 9.9 30.4 0 0.0 8'2" 133.9 101.1 27.7 85.0 474.5 153.5 115.4 6/30/2018 Jun 8.4 25.8 5.3 16.3 5'8" 295.1 97.9 21.2 65.1 9.6 29.5 0 0.0 15'1" 59.6 175.4 37.7 115.7 354.7 273.3 161.4 7/31/2018 Jul 9.3 28.5 9.2 28.2 10'0" 193.7 199.3 35.4 108.6 9.5 29.2 0 0.0 22'0" 17.0 218.0 42.9 131.7 210.7 417.3 189.0 8/31/2018 Aug 9.7 29.8 9.7 29.8 11'7" 163.6 229.4 12 36.8 5.8 17.8 0 0.0 20'9" 22.0 213.0 0.0 0.0 185.6 442.4 47.6 9/30/2018 Sep 9 27.6 9 27.6 13'11" 123.9 269.1 16 49.1 10.7 32.8 0 0.0 19'3" 36.2 198.8 0.0 0.0 160.1 467.9 60.5 10/31/2018 Oct 8.9 27.3 8.9 27.3 15'2" 106.0 287.0 16.2 49.7 10.0 30.7 0 0.0 11' 45.6 189.4 0.0 0.0 151.6 476.4 58.0 11/30/2018 Nov 10.5 32.2 5.8 17.8 15'1" 107.2 285.8 14.9 45.7 5.6 17.2 0 0.0 14'10" 60.9 174.1 0.0 0.0 168.1 459.9 35.0 12/31/2018 Dec 11.7 35.9 0 0.0 13'6" 131.2 261.8 15.2 46.6 0 0.0 0 0.0 11'2" 94.9 140.1 0.0 0.0 226.1 401.9 0.0 Total: 135.3 415.2 47.9 147.0 193.1 592.6 67.1 205.9 0.0 0.0 109.5 336.0 689.0 2019
1/31/2019 Jan 17.4 53.4 0 0.0 10'5" 185.4 207.6 36.7 112.6 0 0.0 0 0.0 8'3" 132.8 102.2 0 0.0 318.2 309.8 0.0 2/28/2019 Feb 23.3 71.5 0 0.0 6'6" 271.9 121.1 4.8 14.7 0 0.0 0 0.0 6'6" 157.3 77.7 0 0.0 429.22 198.8 0.0 3/31/2019 Mar 20.2 62.0 0 0.0 3'6" 350.4 42.6 7.6 23.3 0 0.0 0 0.0 4'8" 185.2 49.8 0 0.0 535.64 92.4 0.0 4/30/2019 Apr 11.9 36.5 0 0.0 2'9" 271.4 121.6 15.8 48.5 4.2 12.9 0 0.0 3'2" 209.8 25.2 2 6.1 481.19 146.8 19.0 5/31/2019 May 12.7 39.0 0 0.0 3'6" 350.4 42.6 24.0 73.7 5.8 17.8 0 0.0 4'8" 185.2 49.8 20.9 64.1 535.64 92.4 81.9 6/30/2019 Jun 10 30.7 5.2 16.0 5'10" 288.5 104.5 26.5 81.3 12.3 37.7 0 0.0 7'3" 146.6 88.4 29 89.0 435.06 192.9 142.7 7/31/2019 Jul 7.6 23.3 9.9 30.4 8'11" 217.9 175.1 22.9 70.3 13.8 42.4 0 0.0 14'7" 61.5 173.5 40.6 124.6 279.44 348.6 197.3 8/31/2019 Aug 10 30.7 10 30.7 10'7" 184.2 208.8 13.4 41.1 11.8 36.2 0 0.0 17'2" 40.3 194.7 6.2 19.0 224.52 403.5 85.9 9/30/2019 Sep 9.6 29.5 9.4 28.8 12'6" 148.3 244.7 13.7 42.0 10.4 31.9 0 0.0 17'1" 40.9 194.1 0 0.0 189.23 438.8 60.8 10/31/2019 Oct 9 27.6 9 27.6 14'3" 119.6 273.4 0.0 12.2 37.4 0 0.0 16'5" 46.0 189.0 0 0.0 165.61 462.4 65.1 11/30/2019 Nov 7.2 22.1 5.1 15.7 14'1" 121.6 271.4 9.3 28.5 5.7 17.5 0 0.0 14'11" 58.5 176.5 0 0.0 180.14 447.9 33.1 12/31/2019 Dec 12.6 38.7 0 0.0 12'3" 152.2 240.8 0 0.0 0 0.0 0 0.0 13'2" 75.1 159.9 0 0.0 227.3 400.7 0.0 Total: 151.5 464.9 48.6 149.1 174.7 536.1 76.2 233.8 0.0 0.0 98.7 302.9 685.9

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289
Section 13, Item J.

ARSA Facilities Monthly Status Reports - Provided by ARSA Staff Date
Sutter
Creek
WWTP
Flow
(mg)
Sutter
Creek
WWTP
(ac ft)
Bowers
Irrigation
(mg)
Bowers
Volume
irrigated
(ac ft)
Henderson
Freeboard
Volume in
Henderson (af)
Capacity
Remaining in
Henderson
Henderson
Outflow (mg)
Henderson
outflow (ac ft)
Hoskins
Irrigation
(mg)
Hoskins
Volume
irrigated (ac
ft)
Mule Creek
Inflow (mg)
Mule Creek
Inflow (ac
ft)
Preston
Freeboard
Volume in
Preston (af)
Capacity Remaining
in Preston (ac ft)
Outflow to
Ione (mg)
Volume sent
to Ione (ac ft)
TOTAL Ac Ft
of Effluent in the
system
TOTAL
Remaining
Capacity for
Winter (ac
ft)
TOTAL

USED FOR

IRRIGATI
O
N (ac ft)
1/31/2020 Jan 10.3 31.6 0 0.0 11'2" 172.9 220.1 8.5 26.1 0 0.0 0 0.0 12'2" 85.5 149.5 0 0.0 258.4 369.6 0.0 2/29/2020. Feb 8 24.6 0 0.0 10'7" 184.2 208.8 3.5 10.7 0 0.0 0 0.0 11'7" 91.9 143.1 0 0.0 276.08 351.9 0.0 3/31/2020 Mar 12.85 39.4 0 0.0 8'11" 214.9 178.1 7.4 22.7 0 0.0 0 0.0 10'1" 109.4 125.6 0 0.0 324.26 303.7 0.0 4/30/2020 Apr 12.61 38.7 0 0.0 7'8" 246.1 146.9 6.3 19.3 0 0.0 0 0.0 10'8" 102.4 132.6 8.84 27.1 348.5 279.5 27.1 5/31/2020 May 8.2 25.2 1.4 4.3 8'6" 227.5 165.5 4.2 12.9 7.5 23.0 0 0.0 13'11" 67.8 167.2 23.9 73.3 295.3 332.7 100.7 6/30/2020 Jun 8.3 25.5 8.3 25.5 11'6" 166.5 226.5 6.3 19.3 5.7 17.5 0 0.0 19'6" 25.1 209.9 28.9 88.7 191.6 436.4 131.7 7/31/2020 Jul 8.3 25.5 8.3 25.5 14'11" 108.5 284.5 19.2 58.9 3.9 12.0 0 0.0 15'10" 50.7 184.3 0 0.0 159.2 468.8 37.4 8/31/2020 Aug 8.3 25.5 8.3 25.5 17'11" 67.6 325.4 13.3 40.8 2.3 7.1 0 0.0 14'0" 67.0 168.0 0 0.0 134.56 493.4 32.5 9/30/2020 Sep 8.2 25.2 8.2 25.2 19'2" 53.3 339.7 8.4 25.8 2.3 7.1 14 43.0 13'0" 76.8 158.2 13.9 42.7 130.09 497.9 74.9 10/31/2020 Oct 8.8 27.0 8.8 27.0 21'2" 33.7 359.3 11.9 36.5 2.4 7.4 0 0.0 17'9" 36.2 198.8 23.4 71.8 69.86 558.1 106.2 11/30/2020 Nov 9.1 27.9 3.5 10.7 22' 26.8 366.2 7.62 23.4 2.3 7.1 0 0.0 18'8" 30.1 204.9 30.7 94.2 56.89 571.1 112.0 12/31/2020 Dec 9.9 30.4 0 0.0 21'0" 35.9 357.1 8.8 27.0 0 0.0 0 0.0 16'8" 44.1 190.9 0 0.0 79.97 548.0 0.0 Total: 112.9 346.4 46.8 143.6 105.4 323.4 26.4 81.0 14.0 43.0 129.6 397.9 622.5 2021
1/31/2021 Jan 12.6 38.7 0 0.0 17'6" 72.7 320.3 3.9 12.0 0 0.0 0 0.0 15'3" 55.6 179.4 0 0.0 128.3 499.7 0.0 2/28/2021 Feb 10.9 33.5 0 0.0 16'1" 91.5 301.5 2.6 8.0 0 0.0 0 0.0 14'9" 60.0 175.0 0 0.0 151.49 476.5 0.0 3/31/2021 Mar 11.9 36.5 0 0.0 13'1" 138.2 254.8 3.5 10.7 0 0.0 0 0.0 14'7" 61.5 173.5 0 0.0 199.65 428.4 0.0 4/30/2021 Apr 10.2 31.3 0 0.0 14'7" 113.7 279.3 0.0 0 0.0 0 0.0 16'11" 42.2 192.8 20.7 63.5 155.85 472.2 63.5 5/31/2021 May 10.7 32.8 6.6 20.3 19'10" 46.3 346.7 27.2 83.5 0 0.0 0 0.0 21'4" 15.7 219.3 36.2 111.1 61.97 566.0 131.3 6/30/2021 Jun 10.4 31.9 7.4 22.7 21'5" 31.6 361.4 8.7 26.7 0 0.0 0 0.0 20'10" 18.0 217.0 1.9 5.8 49.6 578.4 28.5 7/31/2021 Jul 10.2 31.3 7.1 21.8 22'1" 26.2 366.8 3.9 12.0 0.2 0.6 0 0.0 21'0' 17.2 217.8 0 0.0 43.39 584.6 22.4 8/31/2021 Aug 10.1 31.0 6.9 21.2 22'6" 23.0 370.0 5.6 17.2 2 6.1 0 0.0 21'6" 15.0 220.0 0 0.0 37.96 590.0 27.3 9/30/2021 Sep 9.7 29.8 5.2 16.0 23'8" 15.2 377.8 6.9 21.2 1.7 5.2 0 0.0 21'0" 17.2 217.8 0 0.0 32.38 595.6 21.2 10/31/2021 Oct 13.8 42.4 3.6 11.0 20'5" 40.6 352.4 5 15.3 0 0.0 0 0.0 19'1" 27.5 207.5 0 0.0 68.06 559.9 11.0 11/30/2021 Nov 11.7 35.9 0 0.0 18'11" 56.0 337.0 7.9 24.2 0 0.0 0 0.0 18'1" 33.9 201.1 0 0.0 89.89 538.1 0.0 12/31/2021 Dec 21.2 65.1 0 0.0 14'2" 120.2 272.8 0.0 0 0.0 0 0.0 14'8" 60.8 174.2 0 0.0 180.98 447.0 0.0 Total: 143.4 440.1 36.8 112.9 75.2 230.8 3.9 12.0 0.0 0.0 58.8 180.5 305.4 2022
1/31/2022 Jan 12.9 39.6 0 0.0 12'9" 142.9 250.1 6.2 19.0 0 0.0 0 0.0 13'9" 69.4 165.6 0 0.0 212.25 415.8 0.0 2/28/2022 Feb 10.6 32.5 0 0.0 12'0" 157.3 235.7 5.5 16.9 0 0.0 0 0.0 12'10" 78.5 156.5 0 0.0 235.79 392.2 0.0 3/31/2022 Mar 11 33.8 0 0.0 11'8" 163.4 229.6 2.7 8.3 0 0.0 0 0.0 12'1" 86.4 148.6 1.6 4.9 249.83 378.2 4.9 4/30/2022 Apr 12.7 39.0 0 0.0 11'3" 171.3 221.7 9.1 27.9 0 0.0 0 0 10'1" 109.4 125.6 0.1 0.3 280.62 347.4 0.3 5/31/2022 May 12.1 37.1 0 0.0 12'2" 154.3 238.7 11.7 35.9 0 0.0 0 0 9'0" 122.9 112.1 1.7 5.2 277.21 350.8 5.2 6/30/2022 Jun 11.2 34.4 10.1 31.0 14'3" 118.9 274.1 11.2 34.4 7.2 22.1 0 0 8'11" 124.0 111.0 5 15.3 242.9 385.1 68.4 7/31/2022 Jul 11.6 35.6 11.6 35.6 16'3" 89.2 303.8 9.4 28.8 8.1 24.9 0 0 9'3" 119.7 115.3 0 0.0 208.9 419.1 60.5 8/31/2022 Aug 9.8 30.1 9.8 30.1 18'1" 65.6 327.4 8.4 25.8 7.7 23.6 0 0 9'8" 114.5 120.5 0.5 1.5 180.1 447.9 55.2 9/30/2022 Sep 8.5 26.1 7.6 23.3 9'8" 48.9 344.1 8.6 26.4 6.5 19.9 0 0 9'9" 113.4 121.6 0.9 2.8 162.3 465.7 46.0 10/31/2022 Oct 9.3 28.5 9.3 28.5 22'0" 26.8 366.2 9.8 30.1 8.7 26.7 0 0 11'8" 91.0 144.0 4.5 13.8 117.8 510.2 69.0 11/30/2022 Nov 9.9 30.4 0 0.0 19'7" 48.8 344.2 3.3 10.1 0 0.0 0 0 15'2" 56.6 178.4 11.3 34.7 105.4 522.6 34.7 12/31/2022 Dec 20.3 62.3 0 0.0 13'10" 125.6 267.4 2.8 8.6 0 0.0 0 0 13'0" 76.8 158.2 0 0.0 202.41 425.6 0.0 Total: 139.9 429.3 48.4 148.5 88.7 272.2 38.2 117.2 0.0 0.0 25.6 78.6 344.3 2023
1/31/2023 Jan 28.1 86.2 0.0 0.0 7'6" 249.9 143.1 3.0 9.2 0.0 0.0 0.0 0.0 9'8" 114.5 120.5 0.0 0.0 364.4 263.6 0.0 2/28/2023 Feb 14.5 44.5 0.0 0.0 5'7" 295.7 97.3 0.0 0.0 0.0 0.0 0.0 9'4" 118.7 116.3 0.0 0.0 414.4 213.6 0.0 3/31/2023 Mar 24.3 74.6 0.0 0.0 3'9" 343.0 50.0 18.3 56.2 0.0 0.0 0.0 0.0 4'10" 235.0 0.0 0.0 343.0 285.0 0.0 4/30/2023 Apr 9.5 29.2 0.0 0.0 3'2" 358.8 34.2 8.2 25.2 6.3 19.3 0.0 0.0 5'0" 180.0 55.0 2.1 6.4 538.8 89.2 25.8 5/31/2023 May 8.9 27.3 0.0 0.0 3'8" 345.3 47.7 10.9 33.5 10.0 30.7 0.0 0.0 8'2" 133.9 101.1 18.8 57.7 479.2 148.8 88.4 6/30/2023 Jun 9.2 28.2 5.7 17.5 6'2" 281.3 111.7 21.5 66.0 9.7 29.8 0.0 0.0 11'1" 97.5 137.5 25.8 79.2 378.8 249.2 126.4 7/31/2023 Jul 9.1 27.9 9.1 27.9 11'4" 169.7 223.3 31.0 95.1 2.2 6.8 0.0 0.0 11'5" 93.8 141.2 29.5 90.5 263.5 364.5 125.2 8/31/2023 Aug 10.6 32.5 10.6 32.5 17'11" 67.6 325.4 29.6 90.8 4.9 15.0 0.0 0.0 13'6" 71.8 163.2 26.9 82.6 139.4 488.6 130.1 9/30/2023 Sep 10.5 32.2 10.5 32.2 20'0" 44.6 348.4 9.7 29.8 8.8 27.0 0.0 0.0 16'0" 49.3 185.7 5.3 16.3 93.9 534.1 75.5 10/31/2023 Oct 11.2 34.4 7.9 24.2 19'10" 46.3 346.7 5.4 16.6 3.2 9.8 0.0 0.0 16'2" 48.0 187.0 0.0 0.0 94.3 533.7 34.1 11/30/2023 Nov 10.3 31.6 0.0 0.0 18'7" 59.7 333.3 3.6 11.0 0.0 0.0 0.0 0.0 15'11" 50.0 185.0 0.0 0.0 109.7 518.3 0.0 12/31/2023 Dec 10.9 33.5 0.0 0.0 17'0" 79.1 313.9 5.2 16.0 0.0 0.0 0.0 0.0 15'1" 57.1 177.9 0.0 0.0 136.2 491.8 0.0 Total: 157.1 482.1 43.8 134.4 146.4 449.3 45.1 138.4 0.0 0.0 108.4 332.7 605.5 2020

Page 2 of 3 ends

290
Section 13, Item J.

USED FOR

IRRIGATI
O
N (ac ft)
2024
1/31/2024 Jan 14.2 43.6 0.0 0.0 14'3" 118.9 274.1 0.0 0.0 0.0 0.0 0.0 13'5" 71.8 163.2 0.0 0.0 190.7 437.3 0.0 2/29/2024 Feb 17.1 52.5 0.0 0.0 10'11" 177.7 215.3 4.4 13.5 0.0 0.0 0.0 0.0 11'9" 90.0 145.0 0.0 0.0 267.7 360.3 0.0 3/31/2024 Mar 17.8 54.6 0.0 0.0 8'5" 229.3 163.7 4.4 13.5 0.0 0.0 0.0 0.0 10'8" 102.4 132.6 0.0 0.0 331.7 296.3 0.0 4/30/2024 Apr 13.1 40.2 0.0 0.0 7'8" 246.1 146.9 3.0 9.2 0.0 0.0 0.0 0.0 9'7" 115.5 119.5 0.5 1.5 361.6 266.4 1.5 5/31/2024 May 10.9 33.5 0.0 0.0 9'0" 216.7 176.3 18.2 55.9 0.0 0.0 0.0 0.0 11'5" 93.8 141.2 18.9 58.0 310.5 317.5 58.0 6/30/2024 Jun 10.1 31.0 9.4 28.8 13'1" 138.2 254.8 24.6 75.5 1.7 5.2 0.0 0.0 15'7" 52.8 182.2 31.8 97.6 191.0 437.0 131.7 7/31/2024 Jul 10.0 30.7 10.0 30.7 19'11" 45.4 347.6 28.7 88.1 0.0 0.0 0.0 0.0 19'2" 27.0 208.0 31.8 97.6 72.4 555.6 128.3 8/31/2024 Aug 0.0 393.0 0.0 0.0 0.0 0.0 235.0 0.0 0.0 628.0 0.0 9/30/2024 Sep 0.0 393.0 0.0 0.0 0.0 0.0 235.0 0.0 0.0 628.0 0.0 10/31/2024 Oct 0.0 393.0 0.0 0.0 0.0 0.0 235.0 0.0 0.0 628.0 0.0 11/30/2024 Nov 0.0 393.0 0.0 0.0 0.0 0.0 235.0 0.0 0.0 628.0 0.0 12/31/2024 Dec 0.0 393.0 0.0 0.0 0.0 0.0 235.0 0.0 0.0 628.0 0.0 Total: 93.2 286.0 19.4 59.5 83.3 255.6 1.7 5.2 0.0 0.0 83.0 254.7 319.5

Page 3 of 3 ends

291
Section 13, Item J.

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
6/1/2017 329,600
6/2/2017 315,000
6/3/2017 312,600
6/4/2017 292,400
6/5/2017 324,400
6/6/2017 297,400
6/7/2017 346,000
6/8/2017 311,400
6/9/2017 310,600
6/10/2017 284,600
6/11/2017 297,000
6/12/2017 296,000
6/13/2017 328,300
6/14/2017 301,700
6/15/2017 296,000
6/16/2017 293,000
6/17/2017 282,600
6/18/2017 269,400
6/19/2017 310,400
6/20/2017 304,200
6/21/2017 296,400
6/22/2017 311,600
6/23/2017 293,000
6/24/2017 260,000
6/25/2017 258,000
6/26/2017 314,200
6/27/2017 282,400
6/28/2017 289,600
6/29/2017 268,800
6/30/2017 267,600
7/1/2017 193,000
7/2/2017 353,800
7/3/2017 310,600
7/4/2017 242,800
7/5/2017 286,400
7/6/2017 295,600
7/7/2017 275,000
7/8/2017 232,400
7/9/2017 238,800
7/10/2017 280,200
7/11/2017 278,400
7/12/2017 262,000
7/13/2017 310,800
7/14/2017 338,000
7/15/2017 260,800
7/16/2017 256,200
7/17/2017 275,000
7/18/2017 283,200
7/19/2017 340,600
7/20/2017 293,400
7/21/2017 276,000
7/22/2017 265,200
7/23/2017 252,000
7/24/2017 307,300
7/25/2017 275,700
7/26/2017 276,800
7/27/2017 290,600
7/28/2017 291,400
7/29/2017 261,200
7/30/2017 260,600
7/31/2017 299,400
8/1/2017 290,000
8/2/2017 264,600
8/3/2017 293,400
8/4/2017 308,600
8/5/2017 257,200
8/6/2017 250,600
8/7/2017 348,800
8/8/2017 304,200
8/9/2017
8/10/2017
8/11/2017 266,000
8/12/2017 332,400
8/13/2017 346,000
8/14/2017 415,400
8/15/2017 416,200
8/16/2017 454,000
8/17/2017 315,000
8/18/2017 272,000

Page 1 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
8/19/2017 259,400
8/20/2017 254,200
8/21/2017 300,000
8/22/2017 255,600
8/23/2017 281,400
8/24/2017 271,400
8/25/2017 326,600
8/26/2017 271,000
8/27/2017 271,800
8/28/2017 296,000
8/29/2017 296,400
8/30/2017 289,200
8/31/2017 275,600
9/1/2017 303,600
9/2/2017 267,400
9/3/2017 249,800
9/4/2017 276,600
9/5/2017 248,800
9/6/2017 269,000
9/7/2017 300,200
9/8/2017 278,800
9/9/2017 279,000
9/10/2017 266,000
9/11/2017 307,200
9/12/2017 279,400
9/13/2017 300,400
9/14/2017 294,200
9/15/2017 288,600
9/16/2017 236,400
9/17/2017 235,200
9/18/2017 291,000
9/19/2017 279,200
9/20/2017 284,000
9/21/2017 268,200
9/22/2017 300,600
9/23/2017 313,000
9/24/2017 289,000
9/25/2017 314,000
9/26/2017 289,400
9/27/2017 304,600
9/28/2017 329,600
9/29/2017 482,000
9/30/2017 297,400
10/1/2017 280,000
10/2/2017 284,400
10/3/2017 261,800
10/4/2017 265,400
10/5/2017 304,600
10/6/2017 282,600
10/7/2017 315,500
10/8/2017 280,300
10/9/2017 276,400
10/10/2017 310,400
10/11/2017 273,600
10/12/2017 299,400
10/13/2017 268,600
10/14/2017 251,400
10/15/2017 274,000
10/16/2017 304,000
10/17/2017 267,800
10/18/2017 249,600
10/19/2017 263,600
10/20/2017 288,600
10/21/2017 233,600
10/22/2017 242,200
10/23/2017 17,600
10/24/2017 39,400
10/25/2017 226,000
10/26/2017 289,900
10/27/2017 239,500
10/28/2017 238,000
10/29/2017 243,800
10/30/2017 403,000
10/31/2017 377,000
11/1/2017 427,200
11/2/2017 442,800

Page 2 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
11/3/2017 390,600
11/4/2017 337,800
11/5/2017 321,400
11/6/2017 344,200
11/7/2017 360,400
11/8/2017 291,800
11/9/2017 319,000
11/10/2017 278,400
11/11/2017 226,800
11/12/2017 231,600
11/13/2017 265,600
11/14/2017 261,000
11/15/2017 437,600
11/16/2017 963,800
11/17/2017 476,000
11/18/2017 347,600
11/19/2017 278,000
11/20/2017 310,400
11/21/2017 309,000
11/22/2017 372,200
11/23/2017 304,000
11/24/2017 368,600
11/25/2017 354,600
11/26/2017 772,600
11/27/2017 642,200
11/28/2017 420,000
11/29/2017 341,400
11/30/2017 353,200
12/1/2017 319,000
12/2/2017 335,000
12/3/2017 335,200
12/4/2017 312,600
12/5/2017 344,400
12/6/2017 319,400
12/7/2017 370,600
12/8/2017 308,400
12/9/2017 297,600
12/10/2017 297,000
12/11/2017 306,800
12/12/2017 304,800
12/13/2017 320,200
12/14/2017 297,000
12/15/2017 287,800
12/16/2017 283,800
12/17/2017 280,200
12/18/2017 324,400
12/19/2017 347,000
12/20/2017 374,600
12/21/2017 322,800
12/22/2017 355,800
12/23/2017 288,400
12/24/2017 259,000
12/25/2017 244,000
12/26/2017 340,600
12/27/2017 325,400
12/28/2017 335,600
12/29/2017 284,800
12/30/2017 265,400
12/31/2017 252,400
1/1/2018 256,800
1/2/2018 321,600
1/3/2018 318,200
1/4/2018 301,000
1/5/2018 368,400
1/6/2018 400,000
1/7/2018 316,200
1/8/2018 1,023,000
1/9/2018 1,096,000
1/10/2018 630,800
1/11/2018 485,400
1/12/2018 455,400
1/13/2018 364,400
1/14/2018 348,200
1/15/2018 360,800
1/16/2018 360,400
1/17/2018 344,000

Page 3 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
1/18/2018 417,600
1/19/2018 442,600
1/20/2018 353,800
1/21/2018 336,800
1/22/2018 385,600
1/23/2018 353,000
1/24/2018 511,600
1/25/2018 567,600
1/26/2018 474,000
1/27/2018 413,600
1/28/2018 390,200
1/29/2018 364,400
1/30/2018 516,000
1/31/2018 370,800
2/1/2018 357,200
2/2/2018 328,600
2/3/2018 332,000
2/4/2018 302,200
2/5/2018 340,000
2/6/2018 332,800
2/7/2018 366,200
2/8/2018 322,400
2/9/2018 332,800
2/10/2018 299,800
2/11/2018 264,800
2/12/2018 282,800
2/13/2018 323,600
2/14/2018 269,000
2/15/2018 289,600
2/16/2018 277,200
2/17/2018 265,600
2/18/2018 249,400
2/19/2018 274,200
2/20/2018 275,800
2/21/2018 301,400
2/22/2018 306,000
2/23/2018 313,600
2/24/2018 283,800
2/25/2018 275,600
2/26/2018
2/27/2018
2/28/2018
3/1/2018 734,400
3/2/2018 983,800
3/3/2018 872,600
3/4/2018 597,800
3/5/2018 499,000
3/6/2018 451,600
3/7/2018 404,400
3/8/2018 409,200
3/9/2018 356,800
3/10/2018 325,600
3/11/2018 352,200
3/12/2018 443,800
3/13/2018 1,304,400
3/14/2018 1,205,800
3/15/2018 1,243,200
3/16/2018 1,391,400
3/17/2018 934,600
3/18/2018 745,600
3/19/2018 700,600
3/20/2018 659,000
3/21/2018 1,046,000
3/22/2018 1,412,200
3/23/2018 931,400
3/24/2018 728,600
3/25/2018 656,200
3/26/2018 566,200
3/27/2018 476,600
3/28/2018 457,200
3/29/2018 427,200
3/30/2018 393,000
3/31/2018 391,800
4/1/2018 355,000

Page 4 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
4/2/2018 377,200
4/3/2018 384,200
4/4/2018 393,600
4/5/2018 448,600
4/6/2018 1,042,800
4/7/2018 1,126,600
4/8/2018 745,800
4/9/2018 640,600
4/10/2018 556,500
4/11/2018 503,300
4/12/2018 479,400
4/13/2018 451,000
4/14/2018 431,000
4/15/2018 420,400
4/16/2018 497,800
4/17/2018 466,000
4/18/2018 447,000
4/19/2018 418,400
4/20/2018 375,800
4/21/2018 362,000
4/22/2018 359,800
4/23/2018 409,800
4/24/2018 379,800
4/25/2018 364,000
4/26/2018 371,000
4/27/2018 350,200
4/28/2018 317,800
4/29/2018 309,000
4/30/2018 365,400
5/1/2018 353,400
5/2/2018 344,400
5/3/2018 337,600
5/4/2018 293,000
5/5/2018 272,400
5/6/2018 265,600
5/7/2018 313,000
5/8/2018 297,200
5/9/2018 181,000
5/10/2018 308,200
5/11/2018 291,000
5/12/2018 260,400
5/13/2018 316,200
5/14/2018 238,400
5/15/2018 284,200
5/16/2018 307,600
5/17/2018 291,600
5/18/2018 300,200
5/19/2018 286,800
5/20/2018 254,600
5/21/2018 323,800
5/22/2018 325,600
5/23/2018 311,200
5/24/2018 319,600
5/25/2018 330,200
5/26/2018 297,800
5/27/2018 294,600
5/28/2018 324,800
5/29/2018 310,200
5/30/2018 298,200
5/31/2018 342,183
6/1/2018 296,200
6/2/2018 273,800
6/3/2018 272,400
6/4/2018 287,600
6/5/2018 295,800
6/6/2018 296,600
6/7/2018 278,800
6/8/2018 288,400
6/9/2018 249,800
6/10/2018 266,400
6/11/2018 299,800
6/12/2018 314,800
6/13/2018 305,800
6/14/2018 324,800
6/15/2018 299,800
6/16/2018 283,400

Page 5 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
6/17/2018 241,400
6/18/2018 294,200
6/19/2018 313,600
6/20/2018 285,200
6/21/2018 275,000
6/22/2018 274,400
6/23/2018 234,600
6/24/2018 229,200
6/25/2018 282,600
6/26/2018 298,800
6/27/2018 190,000
6/28/2018 293,800
6/29/2018 317,400
6/30/2018 257,200
7/1/2018 267,200
7/2/2018 325,600
7/3/2018 321,400
7/4/2018 259,000
7/5/2018 319,200
7/6/2018 336,400
7/7/2018 262,000
7/8/2018 271,800
7/9/2018 273,400
7/10/2018 305,400
7/11/2018 302,200
7/12/2018 301,000
7/13/2018 305,400
7/14/2018 271,000
7/15/2018 276,800
7/16/2018 317,200
7/17/2018 328,800
7/18/2018 310,600
7/19/2018 311,200
7/20/2018 329,800
7/21/2018 272,400
7/22/2018 281,500
7/23/2018 300,500
7/24/2018 292,800
7/25/2018 290,600
7/26/2018 306,000
7/27/2018 345,800
7/28/2018 285,400
7/29/2018 288,200
7/30/2018 313,800
7/31/2018 322,600
8/1/2018 295,800
8/2/2018 314,200
8/3/2018 311,800
8/4/2018 281,800
8/5/2018 313,400
8/6/2018 328,600
8/7/2018 311,200
8/8/2018 337,800
8/9/2018 350,200
8/10/2018 318,200
8/11/2018 295,600
8/12/2018 322,400
8/13/2018 336,400
8/14/2018 331,000
8/15/2018 360,000
8/16/2018 297,400
8/17/2018 314,200
8/18/2018 294,600
8/19/2018 283,800
8/20/2018 342,800
8/21/2018 351,400
8/22/2018 364,800
8/23/2018 335,000
8/24/2018 298,600
8/25/2018 291,400
8/26/2018 277,000
8/27/2018 302,200
8/28/2018 275,400
8/29/2018 299,600

Page 6 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
8/30/2018 295,200
8/31/2018 317,600
9/1/2018 209,800
9/2/2018 244,200
9/3/2018 284,200
9/4/2018 316,600
9/5/2018 306,000
9/6/2018 334,000
9/7/2018 354,400
9/8/2018 294,000
9/9/2018 272,400
9/10/2018 321,600
9/11/2018 304,600
9/12/2018 303,400
9/13/2018 318,200
9/14/2018 263,200
9/15/2018 263,800
9/16/2018 280,600
9/17/2018 329,200
9/18/2018 246,800
9/19/2018 276,800
9/20/2018 274,800
9/21/2018 298,400
9/22/2018 246,000
9/23/2018 333,800
9/24/2018 355,800
9/25/2018 404,200
9/26/2018 355,000
9/27/2018 356,400
9/28/2018 331,000
9/29/2018 257,000
9/30/2018 268,000
10/1/2018 273,200
10/2/2018 258,000
10/3/2018 286,200
10/4/2018 322,200
10/5/2018 304,800
10/6/2018 256,000
10/7/2018 266,600
10/8/2018 337,600
10/9/2018 298,200
10/10/2018 266,000
10/11/2018 236,600
10/12/2018 270,200
10/13/2018 236,800
10/14/2018 232,200
10/15/2018 252,200
10/16/2018 299,800
10/17/2018 303,800
10/18/2018 305,000
10/19/2018 279,400
10/20/2018 258,800
10/21/2018 291,800
10/22/2018 330,400
10/23/2018 336,600
10/24/2018 316,600
10/25/2018 313,000
10/26/2018 305,600
10/27/2018 290,600
10/28/2018 293,600
10/29/2018 321,800
10/30/2018 300,200
10/31/2018 305,600
11/1/2018 303,800
11/2/2018 287,600
11/3/2018 287,400
11/4/2018 301,800
11/5/2018 296,400
11/6/2018 263,600
11/7/2018 305,000
11/8/2018 289,000
11/9/2018 299,000
11/10/2018 251,200
11/11/2018 255,200
11/12/2018 304,000
11/13/2018 253,600

Page 7 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
11/14/2018 302,400
11/15/2018 313,400
11/16/2018 278,800
11/17/2018 270,000
11/18/2018 269,600
11/19/2018 312,800
11/20/2018 310,400
11/21/2018 365,600
11/22/2018 386,400
11/23/2018 591,200
11/24/2018 453,600
11/25/2018 367,600
11/26/2018 338,800
11/27/2018 329,200
11/28/2018 470,200
11/29/2018 794,800
11/30/2018 647,600
12/1/2018 616,800
12/2/2018 480,000
12/3/2018 472,000
12/4/2018 407,400
12/5/2018 384,200
12/6/2018 373,600
12/7/2018 280,800
12/8/2018 270,200
12/9/2018 280,000
12/10/2018 298,600
12/11/2018 326,000
12/12/2018 299,000
12/13/2018 298,800
12/14/2018 298,200
12/15/2018 272,400
12/16/2018 338,000
12/17/2018 427,000
12/18/2018 375,600
12/19/2018 309,000
12/20/2018 327,400
12/21/2018 378,000
12/22/2018 352,800
12/23/2018 325,800
12/24/2018 673,600
12/25/2018 593,600
12/26/2018 457,000
12/27/2018 451,400
12/28/2018 370,000
12/29/2018 317,000
12/30/2018 313,400
12/31/2018 342,200
1/1/2019 277,000
1/2/2019 365,800
1/3/2019 342,800
1/4/2019 200,200
1/5/2019 470,800
1/6/2019 612,000
1/7/2019 647,800
1/8/2019 628,400
1/9/2019 821,200
1/10/2019 576,900
1/11/2019 532,100
1/12/2019 367,600
1/13/2019 348,600
1/14/2019 394,000
1/15/2019 582,600
1/16/2019 1,117,000
1/17/2019 1,489,200
1/18/2019 905,200
1/19/2019 621,200
1/20/2019 889,000
1/21/2019 707,200
1/22/2019 586,000
1/23/2019 514,800
1/24/2019 467,200
1/25/2019 449,600
1/26/2019 478,800
1/27/2019 398,200
1/28/2019 418,400

Page 8 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
1/29/2019 393,600
1/30/2019 370,200
1/31/2019 385,600
2/1/2019 387,000
2/2/2019 666,400
2/3/2019 1,032,600
2/4/2019 1,338,200
2/5/2019 988,600
2/6/2019 752,200
2/7/2019 646,400
2/8/2019 540,600
2/9/2019 966,000
2/10/2019 980,600
2/11/2019 694,200
2/12/2019 759,400
2/13/2019 1,284,600
2/14/2019 1,395,400
2/15/2019 1,479,400
2/16/2019 1,139,200
2/17/2019 1,157,600
2/18/2019 889,200
2/19/2019 830,200
2/20/2019 778,000
2/21/2019 596,200
2/22/2019 609,400
2/23/2019 487,000
2/24/2019 443,200
2/25/2019 419,000
2/26/2019 521,200
2/27/2019 771,000
2/28/2019 720,600
3/1/2019 642,000
3/2/2019 1,206,200
3/3/2019 1,674,000
3/4/2019 1,128,000
3/5/2019 966,200
3/6/2019 1,169,000
3/7/2019 1,258,600
3/8/2019 1,017,200
3/9/2019 703,800
3/10/2019 607,600
3/11/2019 559,000
3/12/2019 497,600
3/13/2019 487,600
3/14/2019 458,000
3/15/2019 408,000
3/16/2019 379,800
3/17/2019 369,000
3/18/2019 376,800
3/19/2019 431,600
3/20/2019 434,200
3/21/2019 405,800
3/22/2019 492,400
3/23/2019 742,000
3/24/2019 514,400
3/25/2019 481,600
3/26/2019 483,600
3/27/2019 531,400
3/28/2019 487,800
3/29/2019 491,200
3/30/2019 412,400
3/31/2019 397,400
4/1/2019 469,200
4/2/2019 657,400
4/3/2019 544,800
4/4/2019 494,200
4/5/2019 499,600
4/6/2019 462,600
4/7/2019 385,200
4/8/2019 400,600

Page 9 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
4/9/2019 381,600
4/10/2019 378,800
4/11/2019 379,400
4/12/2019 338,400
4/13/2019 302,800
4/14/2019 313,800
4/15/2019 376,200
4/16/2019 529,800
4/17/2019 445,600
4/18/2019 406,800
4/19/2019 424,200
4/20/2019 349,400
4/21/2019 353,000
4/22/2019 389,800
4/23/2019 366,200
4/24/2019 361,600
4/25/2019 370,000
4/26/2019 331,200
4/27/2019 304,400
4/28/2019 303,800
4/29/2019 327,200
4/30/2019 295,000
5/1/2019 318,600
5/2/2019 316,200
5/3/2019 288,200
5/4/2019 284,400
5/5/2019 293,200
5/6/2019 347,400
5/7/2019 356,800
5/8/2019 256,000
5/9/2019 302,200
5/10/2019 275,800
5/11/2019 270,200
5/12/2019 272,800
5/13/2019 344,600
5/14/2019 339,200
5/15/2019 420,200
5/16/2019 596,800
5/17/2019 441,600
5/18/2019 463,000
5/19/2019 739,000
5/20/2019 566,600
5/21/2019 687,800
5/22/2019 602,400
5/23/2019 546,400
5/24/2019 482,400
5/25/2019 413,600
5/26/2019 419,800
5/27/2019 410,600
5/28/2019 436,800
5/29/2019 416,800
5/30/2019 375,600
5/31/2019 398,600
6/1/2019 334,200
6/2/2019 349,600
6/3/2019 404,000
6/4/2019 411,800
6/5/2019 396,600
6/6/2019 404,800
6/7/2019 421,000
6/8/2019 367,600
6/9/2019 287,800
6/10/2019 339,800
6/11/2019 315,600
6/12/2019 344,800
6/13/2019 351,600
6/14/2019 353,800
6/15/2019 276,800
6/16/2019 292,200
6/17/2019 352,800

Page 10 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
6/18/2019 336,600
6/19/2019 363,400
6/20/2019 343,200
6/21/2019 352,400
6/22/2019 292,800
6/23/2019 294,800
6/24/2019 350,000
6/25/2019 329,600
6/26/2019 270,400
6/27/2019 271,600
6/28/2019 316,800
6/29/2019 259,400
6/30/2019 263,000
7/1/2019 323,800
7/2/2019 325,400
7/3/2019 327,800
7/4/2019 257,200
7/5/2019 325,400
7/6/2019 304,600
7/7/2019 271,200
7/8/2019 332,000
7/9/2019 348,400
7/10/2019 320,400
7/11/2019 322,200
7/12/2019 310,800
7/13/2019 268,200
7/14/2019 280,200
7/15/2019 330,600
7/16/2019 314,400
7/17/2019 330,200
7/18/2019 316,000
7/19/2019 314,000
7/20/2019 289,200
7/21/2019 275,600
7/22/2019 299,600
7/23/2019 449,600
7/24/2019 353,400
7/25/2019 420,000
7/26/2019 792,600
7/27/2019 1,661,600
7/28/2019 245,400
7/29/2019 303,800
7/30/2019 290,200
7/31/2019 441,600
8/1/2019 316,894
8/2/2019 347,800
8/3/2019 294,100
8/4/2019 306,256
8/5/2019 331,544
8/6/2019 338,231
8/7/2019 334,719
8/8/2019 334,744
8/9/2019 317,500
8/10/2019 291,093
8/11/2019 284,319
8/12/2019 348,694
8/13/2019 333,312
8/14/2019 313,575
8/15/2019 357,100
8/16/2019 312,713
8/17/2019 270,562
8/18/2019 299,213
8/19/2019 328,606
8/20/2019 324,094
8/21/2019 323,544
8/22/2019 348,787
8/23/2019 338,456
8/24/2019 296,269
8/25/2019 287,588
8/26/2019 336,987

Page 11 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
8/27/2019 326,088
8/28/2019 332,343
8/29/2019 361,444
8/30/2019 363,513
8/31/2019 303,081
9/1/2019 300,675
9/2/2019 320,369
9/3/2019 356,425
9/4/2019 324,681
9/5/2019 379,031
9/6/2019 327,956
9/7/2019 302,738
9/8/2019 311,125
9/9/2019 371,812
9/10/2019 339,725
9/11/2019 370,425
9/12/2019 324,888
9/13/2019 334,875
9/14/2019 299,744
9/15/2019 295,018
9/16/2019 378,163
9/17/2019 350,325
9/18/2019 353,050
9/19/2019 329,987
9/20/2019 308,100
9/21/2019 268,657
9/22/2019 268,425
9/23/2019 304,762
9/24/2019 323,081
9/25/2019 322,988
9/26/2019 322,275
9/27/2019 325,500
9/28/2019 296,056
9/29/2019 284,419
9/30/2019 361,569
10/1/2019 305,318
10/2/2019 325,925
10/3/2019 315,919
10/4/2019 322,756
10/5/2019 269,619
10/6/2019 289,581
10/7/2019 317,882
10/8/2019 337,718
10/9/2019 172,068
10/10/2019 243,851
10/11/2019 332,738
10/12/2019 281,721
10/13/2019 262,562
10/14/2019 317,314
10/15/2019 312,843
10/16/2019 325,946
10/17/2019 302,608
10/18/2019 281,119
10/19/2019 269,859
10/20/2019 278,593
10/21/2019 333,014
10/22/2019 339,241
10/23/2019 291,573
10/24/2019 315,899
10/25/2019 313,845
10/26/2019 244,313
10/27/2019 195,000
10/28/2019 220,800
10/29/2019 288,800
10/30/2019 289,800
10/31/2019 350,600
11/1/2019 221,400
11/2/2019 155,200
11/3/2019 177,600
11/4/2019 209,600

Page 12 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
11/5/2019 103,600
11/6/2019 146,000
11/7/2019 241,200
11/8/2019 134,600
11/9/2019 119,400
11/10/2019 182,800
11/11/2019 268,600
11/12/2019 258,600
11/13/2019 209,000
11/14/2019 280,400
11/15/2019 289,000
11/16/2019 237,000
11/17/2019 244,800
11/18/2019 305,000
11/19/2019 232,600
11/20/2019 188,000
11/21/2019 222,600
11/22/2019 237,000
11/23/2019 216,800
11/24/2019 239,200
11/25/2019 276,400
11/26/2019 366,000
11/27/2019 410,800
11/28/2019 368,800
11/29/2019 379,600
11/30/2019 319,400
12/1/2019 695,200
12/2/2019 556,400
12/3/2019 424,000
12/4/2019 674,200
12/5/2019 647,000
12/6/2019 553,800
12/7/2019 685,400
12/8/2019 627,000
12/9/2019 464,000
12/10/2019 388,600
12/11/2019 367,600
12/12/2019 387,400
12/13/2019 424,600
12/14/2019 421,200
12/15/2019 354,000
12/16/2019 348,600
12/17/2019 264,600
12/18/2019 304,000
12/19/2019 296,000
12/20/2019 327,200
12/21/2019 289,000
12/22/2019 330,000
12/23/2019 386,600
12/24/2019 307,200
12/25/2019 256,800
12/26/2019 319,800
12/27/2019 310,600
12/28/2019 258,800
12/29/2019 283,900
12/30/2019 309,100
12/31/2019 322,000
1/1/2020 261,400
1/2/2020 334,200
1/3/2020 309,600
1/4/2020 247,000
1/5/2020 269,200
1/6/2020 296,000
1/7/2020 300,800
1/8/2020 288,600
1/9/2020 373,600
1/10/2020 335,600
1/11/2020 337,000
1/12/2020 286,200
1/13/2020 342,400

Page 13 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
1/14/2020 334,800
1/15/2020 357,200
1/16/2020 466,800
1/17/2020 353,000
1/18/2020 300,400
1/19/2020 305,600
1/20/2020 340,200
1/21/2020 326,600
1/22/2020 354,600
1/23/2020 393,200
1/24/2020 303,600
1/25/2020 261,400
1/26/2020 382,800
1/27/2020 368,200
1/28/2020 346,800
1/29/2020 410,000
1/30/2020 398,400
1/31/2020 331,400
2/1/2020 208,000
2/2/2020 181,200
2/3/2020 238,200
2/4/2020 231,000
2/5/2020 245,200
2/6/2020 295,000
2/7/2020 297,000
2/8/2020 204,200
2/9/2020 179,800
2/10/2020 227,600
2/11/2020 294,600
2/12/2020 281,600
2/13/2020 280,400
2/14/2020 296,200
2/15/2020 227,000
2/16/2020 193,400
2/17/2020 269,400
2/18/2020 324,000
2/19/2020 303,400
2/20/2020 286,400
2/21/2020 297,800
2/22/2020 236,600
2/23/2020 223,800
2/24/2020 280,800
2/25/2020 286,800
2/26/2020 314,400
2/27/2020 306,200
2/28/2020 456,200
2/29/2020 594,400
3/1/2020 266,000
3/2/2020 282,200
3/3/2020 318,000
3/4/2020 229,000
3/5/2020 208,400
3/6/2020 208,200
3/7/2020 222,200
3/8/2020 201,600
3/9/2020 190,200
3/10/2020 173,000
3/11/2020 243,400
3/12/2020 201,000
3/13/2020 201,000
3/14/2020 489,200
3/15/2020 1,035,200
3/16/2020 1,767,400
3/17/2020 995,600
3/18/2020 725,000
3/19/2020 545,600
3/20/2020 501,400
3/21/2020 380,600
3/22/2020 341,100
3/23/2020 353,100

Page 14 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
3/24/2020 399,600
3/25/2020 411,200
3/26/2020 380,000
3/27/2020 339,800
3/28/2020 309,000
3/29/2020 310,800
3/30/2020 313,800
3/31/2020 308,200
4/1/2020 328,600
4/2/2020 309,400
4/3/2020 285,400
4/4/2020 366,800
4/5/2020 1,285,200
4/6/2020 1,192,200
4/7/2020 730,200
4/8/2020 615,800
4/9/2020 492,600
4/10/2020 436,000
4/11/2020 402,000
4/12/2020 351,400
4/13/2020 369,000
4/14/2020 373,800
4/15/2020 362,600
4/16/2020 376,400
4/17/2020 350,000
4/18/2020 299,800
4/19/2020 295,000
4/20/2020 314,600
4/21/2020 363,200
4/22/2020 142,800
4/23/2020 360,800
4/24/2020 421,200
4/25/2020 336,200
4/26/2020 271,200
4/27/2020 298,800
4/28/2020 317,600
4/29/2020 319,800
4/30/2020 244,600
5/1/2020 308,400
5/2/2020 186,200
5/3/2020 190,800
5/4/2020 269,800
5/5/2020 264,000
5/6/2020 295,400
5/7/2020 272,200
5/8/2020 300,200
5/9/2020 196,000
5/10/2020 181,200
5/11/2020 303,700
5/12/2020 258,700
5/13/2020 259,000
5/14/2020 286,000
5/15/2020 307,200
5/16/2020 276,400
5/17/2020 482,000
5/18/2020 568,400
5/19/2020 400,800
5/20/2020 358,000
5/21/2020 297,800
5/22/2020 315,200
5/23/2020 215,400
5/24/2020 232,800
5/25/2020 536,800
5/26/2020 313,800
5/27/2020 328,600
5/28/2020 281,225
5/29/2020 273,750
5/30/2020 244,375
5/31/2020 296,600
6/1/2020 275,926

Page 15 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
6/2/2020 283,875
6/3/2020 288,700
6/4/2020 257,844
6/5/2020 269,481
6/6/2020 252,138
6/7/2020 255,143
6/8/2020 279,525
6/9/2020 319,150
6/10/2020 346,282
6/11/2020 349,493
6/12/2020 277,100
6/13/2020 224,119
6/14/2020 233,694
6/15/2020 270,525
6/16/2020 290,887
6/17/2020 288,213
6/18/2020 267,006
6/19/2020 285,231
6/20/2020 234,675
6/21/2020 237,857
6/22/2020 294,843
6/23/2020 264,125
6/24/2020 272,688
6/25/2020 279,044
6/26/2020 271,718
6/27/2020 285,432
6/28/2020 255,162
6/29/2020 279,756
6/30/2020 305,013
7/1/2020 303,906
7/2/2020 295,369
7/3/2020 253,137
7/4/2020 242,244
7/5/2020 243,131
7/6/2020 296,675
7/7/2020 270,719
7/8/2020 307,300
7/9/2020 264,431
7/10/2020 282,819
7/11/2020 231,225
7/12/2020 235,994
7/13/2020 263,062
7/14/2020 262,188
7/15/2020 282,919
7/16/2020 276,762
7/17/2020 290,019
7/18/2020 239,025
7/19/2020 238,775
7/20/2020 287,419
7/21/2020 269,837
7/22/2020 286,063
7/23/2020 273,256
7/24/2020 268,450
7/25/2020 224,531
7/26/2020 219,900
7/27/2020 269,694
7/28/2020 271,019
7/29/2020 276,075
7/30/2020 283,112
7/31/2020 243,594
8/1/2020 230,856
8/2/2020 226,550
8/3/2020 267,894
8/4/2020 289,819
8/5/2020 279,743
8/6/2020 278,988
8/7/2020 276,481
8/8/2020 233,275
8/9/2020 230,250
8/10/2020 284,106

Page 16 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
8/11/2020 286,438
8/12/2020 298,706
8/13/2020 280,106
8/14/2020 269,150
8/15/2020 235,600
8/16/2020 242,194
8/17/2020 293,288
8/18/2020 274,731
8/19/2020 287,756
8/20/2020 267,800
8/21/2020 281,413
8/22/2020 243,206
8/23/2020 248,406
8/24/2020 299,638
8/25/2020 279,450
8/26/2020 248,300
8/27/2020 291,737
8/28/2020 271,082
8/29/2020 239,951
8/30/2020 253,157
8/31/2020 278,472
9/1/2020 282,828
9/2/2020 305,253
9/3/2020 288,473
9/4/2020 268,512
9/5/2020 237,345
9/6/2020 233,074
9/7/2020 262,933
9/8/2020 258,364
9/9/2020 284,871
9/10/2020 272,706
9/11/2020 278,049
9/12/2020 245,169
9/13/2020 243,672
9/14/2020 278,430
9/15/2020 284,736
9/16/2020 278,000
9/17/2020 293,689
9/18/2020 290,178
9/19/2020 253,719
9/20/2020 251,135
9/21/2020 280,676
9/22/2020 270,898
9/23/2020 291,187
9/24/2020 282,218
9/25/2020 282,218
9/26/2020 270,501
9/27/2020 255,724
9/28/2020 284,200
9/29/2020 292,003
9/30/2020 287,510
10/1/2020 267,834
10/2/2020 293,377
10/3/2020 260,220
10/4/2020 259,539
10/5/2020 313,763
10/6/2020 295,309
10/7/2020 292,223
10/8/2020 293,897
10/9/2020 313,689
10/10/2020 253,814
10/11/2020 250,657
10/12/2020 301,911
10/13/2020 284,219
10/14/2020 291,862
10/15/2020 314,592
10/16/2020 273,453
10/17/2020 255,828
10/18/2020 279,360
10/19/2020 296,243

Page 17 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
10/20/2020 284,813
10/21/2020 276,816
10/22/2020 273,359
10/23/2020 282,595
10/24/2020 252,864
10/25/2020 254,138
10/26/2020 295,106
10/27/2020 287,533
10/28/2020 294,847
10/29/2020 264,719
10/30/2020 314,751
10/31/2020 280,261
11/1/2020 274,027
11/2/2020 288,375
11/3/2020 292,317
11/4/2020 314,937
11/5/2020 274,844
11/6/2020 311,819
11/7/2020 267,570
11/8/2020 275,514
11/9/2020 315,828
11/10/2020 289,649
11/11/2020 348,509
11/12/2020 301,677
11/13/2020 316,301
11/14/2020 315,305
11/15/2020 248,126
11/16/2020 315,461
11/17/2020 400,499
11/18/2020 363,183
11/19/2020 352,203
11/20/2020 329,683
11/21/2020 267,070
11/22/2020 273,569
11/23/2020 296,704
11/24/2020 305,833
11/25/2020 318,445
11/26/2020 258,846
11/27/2020 298,103
11/28/2020 267,831
11/29/2020 276,827
11/30/2020 309,586
12/1/2020 290,509
12/2/2020 326,588
12/3/2020 297,709
12/4/2020 302,287
12/5/2020 268,266
12/6/2020 277,938
12/7/2020 311,359
12/8/2020 326,519
12/9/2020 331,662
12/10/2020 338,725
12/11/2020 345,331
12/12/2020 307,379
12/13/2020 382,590
12/14/2020 358,269
12/15/2020 319,150
12/16/2020 356,022
12/17/2020 374,312
12/18/2020 331,969
12/19/2020 296,250
12/20/2020 304,547
12/21/2020 333,037
12/22/2020 326,010
12/23/2020 346,231
12/24/2020 304,397
12/25/2020 273,734
12/26/2020 319,816
12/27/2020 297,800
12/28/2020 347,553

Page 18 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
12/29/2020 325,675
12/30/2020 340,431
12/31/2020
1/1/2021 279,313
1/2/2021 292,900
1/3/2021 298,087
1/4/2021 366,316
1/5/2021 345,616
1/6/2021 331,493
1/7/2021 316,872
1/8/2021 347,813
1/9/2021 280,087
1/10/2021 291,472
1/11/2021 309,563
1/12/2021 347,518
1/13/2021 303,747
1/14/2021 324,031
1/15/2021 337,257
1/16/2021 294,359
1/17/2021 293,966
1/18/2021 342,437
1/19/2021 352,825
1/20/2021 295,385
1/21/2021 331,337
1/22/2021 351,828
1/23/2021 300,053
1/24/2021 377,778
1/25/2021 430,388
1/26/2021 414,559
1/27/2021 822,560
1/28/2021 1,414,122
1/29/2021 852,506
1/30/2021 519,659
1/31/2021 438,585
2/1/2021 439,775
2/2/2021 563,225
2/3/2021 453,168
2/4/2021 396,282
2/5/2021 386,634
2/6/2021 329,603
2/7/2021 333,075
2/8/2021 355,313
2/9/2021 345,437
2/10/2021 359,625
2/11/2021 482,263
2/12/2021 526,731
2/13/2021 438,431
2/14/2021 390,775
2/15/2021 515,769
2/16/2021 420,425
2/17/2021 387,050
2/18/2021 382,556
2/19/2021 385,513
2/20/2021 358,762
2/21/2021 335,063
2/22/2021 356,056
2/23/2021 343,281
2/24/2021 340,913
2/25/2021 328,400
2/26/2021 357,268
2/27/2021 301,350
2/28/2021 301,132
4/1/2021 334,987
4/2/2021 331,419
4/3/2021 313,606
4/4/2021 293,125
4/5/2021 372,182
4/6/2021 331,162
4/7/2021 336,813
4/8/2021 372,456

Page 19 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
4/9/2021 300,725
4/10/2021 290,637
4/11/2021 309,938
4/12/2021 356,075
4/13/2021 340,575
4/14/2021 395,031
4/15/2021 368,725
4/16/2021 365,669
4/17/2021 326,031
4/18/2021 335,638
4/19/2021 364,281
4/20/2021 343,088
4/21/2021 347,887
4/22/2021 345,650
4/23/2021 337,181
4/24/2021 307,250
4/25/2021 328,519
4/26/2021 375,500
4/27/2021 376,187
4/28/2021 349,275
4/29/2021 353,369
4/30/2021 373,581
5/1/2021 293,107
5/2/2021 335,143
5/3/2021 354,963
5/4/2021 355,581
5/5/2021 357,444
5/6/2021 410,531
5/7/2021 343,819
5/8/2021 328,969
5/9/2021 310,068
5/10/2021 387,657
5/11/2021 374,737
5/12/2021 375,150
5/13/2021 357,444
5/14/2021 370,081
5/15/2021 322,038
5/16/2021 327,493
5/17/2021 355,232
5/18/2021 355,412
5/19/2021 333,663
5/20/2021 345,825
5/21/2021 356,875
5/22/2021 299,381
5/23/2021 313,612
5/24/2021 347,744
5/25/2021 366,044
5/26/2021 372,175
5/27/2021 363,056
5/28/2021 363,944
5/29/2021 298,475
5/30/2021 304,131
5/31/2021 318,075
6/1/2021 351,063
6/2/2021 361,562
6/3/2021 344,575
6/4/2021 353,444
6/5/2021 310,831
6/6/2021 313,938
6/7/2021 375,737
6/8/2021 349,156
6/9/2021 354,863
6/10/2021 370,287
6/11/2021 336,738
6/12/2021 325,525
6/13/2021 308,956
6/14/2021 373,081
6/15/2021 383,625
6/16/2021 359,482
6/17/2021 370,050

Page 20 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
6/18/2021 341,418
6/19/2021 311,463
6/20/2021 312,152
6/21/2021 351,487
6/22/2021 348,915
6/23/2021 361,912
6/24/2021 365,716
6/25/2021 355,226
6/26/2021 304,982
6/27/2021 337,139
6/28/2021 355,487
6/29/2021 332,677
6/30/2021 346,808
7/1/2021 366,675
7/2/2021 349,132
7/3/2021 290,578
7/4/2021 280,508
7/5/2021 319,094
7/6/2021 350,209
7/7/2021 347,771
7/8/2021 375,469
7/9/2021 333,906
7/10/2021 285,509
7/11/2021 285,791
7/12/2021 339,873
7/13/2021 358,260
7/14/2021 346,276
7/15/2021 329,902
7/16/2021 338,827
7/17/2021 291,967
7/18/2021 294,703
7/19/2021 313,600
7/20/2021 362,271
7/21/2021 348,297
7/22/2021 331,852
7/23/2021 339,969
7/24/2021 295,907
7/25/2021 293,597
7/26/2021 341,681
7/27/2021 319,928
7/28/2021 346,766
7/29/2021 355,681
7/30/2021 318,806
7/31/2021 298,833
8/1/2021 301,740
8/2/2021 352,868
8/3/2021 338,704
8/4/2021 342,360
8/5/2021 321,581
8/6/2021 353,714
8/7/2021 304,658
8/8/2021 290,787
8/9/2021 342,657
8/10/2021 306,073
8/11/2021 366,997
8/12/2021 316,761
8/13/2021 360,258
8/14/2021 322,623
8/15/2021 303,580
8/16/2021 330,653
8/17/2021 326,306
8/18/2021 352,595
8/19/2021 330,844
8/20/2021 354,722
8/21/2021 303,719
8/22/2021 311,914
8/23/2021 324,441
8/24/2021 336,601
8/25/2021 329,938
8/26/2021 352,046

Page 21 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
8/27/2021 310,319
8/28/2021 271,333
8/29/2021 278,539
8/30/2021 294,292
8/31/2021 332,011
9/1/2021 321,174
9/2/2021 386,317
9/3/2021 340,084
9/4/2021 309,136
9/5/2021 290,694
9/6/2021 322,330
9/7/2021 333,232
9/8/2021 315,738
9/9/2021 315,206
9/10/2021 357,460
9/11/2021 286,506
9/12/2021 297,434
9/13/2021 314,063
9/14/2021 342,290
9/15/2021 325,647
9/16/2021 348,313
9/17/2021 315,186
9/18/2021 298,817
9/19/2021 289,381
9/20/2021 341,325
9/21/2021 331,781
9/22/2021 337,775
9/23/2021 352,069
9/24/2021 327,609
9/25/2021 304,235
9/26/2021 289,665
9/27/2021 354,413
9/28/2021 316,941
9/29/2021 341,828
9/30/2021 328,565
10/1/2021 329,547
10/2/2021 281,556
10/3/2021 298,847
10/4/2021 327,678
10/5/2021 360,454
10/6/2021 334,984
10/7/2021 370,084
10/8/2021 338,941
10/9/2021 306,412
10/10/2021 303,319
10/11/2021 327,603
10/12/2021 342,350
10/13/2021 328,785
10/14/2021 356,000
10/15/2021 327,653
10/16/2021 302,494
10/17/2021 335,737
10/18/2021 368,750
10/19/2021 348,122
10/20/2021 350,081
10/21/2021 380,769
10/22/2021 380,356
10/23/2021 354,678
10/24/2021 1,731,788
10/25/2021 1,480,584
10/26/2021 657,094
10/27/2021 558,809
10/28/2021 440,660
10/29/2021 441,797
10/30/2021 407,003
10/31/2021 373,781
11/1/2021 384,791
11/2/2021 410,665
11/3/2021 419,153
11/4/2021 363,603

Page 22 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
11/5/2021 325,991
11/6/2021 340,128
11/7/2021 336,219
11/8/2021 410,072
11/9/2021 575,972
11/10/2021 426,734
11/11/2021 423,175
11/12/2021 426,022
11/13/2021 375,734
11/14/2021 383,819
11/15/2021 422,750
11/16/2021 369,656
11/17/2021 406,957
11/18/2021 393,918
11/19/2021 398,819
11/20/2021 344,000
11/21/2021 360,200
11/22/2021 395,756
11/23/2021 398,000
11/24/2021 372,632
11/25/2021 332,575
11/26/2021 369,156
11/27/2021 357,519
11/28/2021 374,031
11/29/2021 384,231
11/30/2021 414,419
12/1/2021 428,287
12/2/2021 380,682
12/3/2021 385,881
12/4/2021 380,244
12/5/2021 365,518
12/6/2021 375,707
12/7/2021 407,237
12/8/2021 390,519
12/9/2021 502,362
12/10/2021 380,275
12/11/2021 352,257
12/12/2021 711,600
12/13/2021 1,276,425
12/14/2021 1,073,893
12/15/2021 824,369
12/16/2021 855,506
12/17/2021 604,663
12/18/2021 502,887
12/19/2021 471,282
12/20/2021 485,262
12/21/2021 441,494
12/22/2021 572,437
12/23/2021 1,376,307
12/24/2021 937,900
12/25/2021 1,110,175
12/26/2021 989,600
12/27/2021 1,566,568
12/28/2021 919,132
12/29/2021 898,475
12/30/2021 677,037
12/31/2021 583,794
1/1/2022 493,656
1/2/2022 465,925
1/3/2022 493,331
1/4/2022 478,807
1/5/2022 481,300
1/6/2022 466,056
1/7/2022 489,287
1/8/2022 425,194
1/9/2022 421,525
1/10/2022 449,363
1/11/2022 441,975
1/12/2022 418,343
1/13/2022 419,532

Page 23 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
1/14/2022 409,137
1/15/2022 388,450
1/16/2022 398,944
1/17/2022 431,831
1/18/2022 387,338
1/19/2022 410,393
1/20/2022 407,788
1/21/2022 385,519
1/22/2022 358,850
1/23/2022 353,250
1/24/2022 383,600
1/25/2022 386,037
1/26/2022 376,569
1/27/2022 404,219
1/28/2022 357,887
1/29/2022 345,069
1/30/2022 359,319
1/31/2022 381,456
2/1/2022 370,912
2/2/2022 386,488
2/3/2022 394,781
2/4/2022 368,188
2/5/2022 354,606
2/6/2022 514,081
2/7/2022 420,944
2/8/2022 440,106
2/9/2022 438,150
2/10/2022 376,506
2/11/2022 372,432
2/12/2022 351,631
2/13/2022 354,744
2/14/2022 416,537
2/15/2022 384,075
2/16/2022 371,456
2/17/2022 362,771
2/18/2022 359,552
2/19/2022 338,289
2/20/2022 349,258
2/21/2022 369,009
2/22/2022 362,382
2/23/2022 344,981
2/24/2022 372,675
2/25/2022 372,924
2/26/2022 336,096
2/27/2022 333,406
2/28/2022 371,913
3/1/2022 359,463
3/2/2022 363,627
3/3/2022 375,536
3/4/2022 379,576
3/5/2022 358,708
3/6/2022 354,003
3/7/2022 387,659
3/8/2022 363,116
3/9/2022 382,587
3/10/2022 361,466
3/11/2022 107,911
3/12/2022 268,566
3/13/2022 276,454
3/14/2022 320,623
3/15/2022 373,206
3/16/2022 379,536
3/17/2022 345,794
3/18/2022 367,818
3/19/2022 332,534
3/20/2022 346,611
3/21/2022 395,014
3/22/2022 376,457
3/23/2022 385,324
3/24/2022 394,829

Page 24 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
3/25/2022 404,906
3/26/2022 338,553
3/27/2022 358,991
3/28/2022 406,297
3/29/2022 385,162
3/30/2022 386,941
3/31/2022 387,570
4/1/2022 376,909
4/2/2022 353,132
4/3/2022 366,156
4/4/2022 395,156
4/5/2022 378,730
4/6/2022 388,825
4/7/2022 385,340
4/8/2022 375,060
4/9/2022 339,312
4/10/2022 352,500
4/11/2022 417,411
4/12/2022 391,230
4/13/2022 390,286
4/14/2022 477,253
4/15/2022 411,956
4/16/2022 522,683
4/17/2022 386,847
4/18/2022 414,356
4/19/2022 429,510
4/20/2022 436,942
4/21/2022 1,044,439
4/22/2022 291,487
4/23/2022 499,078
4/24/2022 463,902
4/25/2022 502,116
4/26/2022 466,175
4/27/2022 427,656
4/28/2022 423,709
4/29/2022 278,107
4/30/2022 305,768
5/1/2022 349,169
5/2/2022 346,794
5/3/2022 397,462
5/4/2022 398,419
5/5/2022 405,453
5/6/2022 407,956
5/7/2022 371,529
5/8/2022 365,334
5/9/2022 393,484
5/10/2022 394,850
5/11/2022 417,991
5/12/2022 418,812
5/13/2022 400,919
5/14/2022 376,813
5/15/2022 377,889
5/16/2022 409,436
5/17/2022 412,543
5/18/2022 410,954
5/19/2022 400,490
5/20/2022 375,816
5/21/2022 390,222
5/22/2022 372,575
5/23/2022 421,722
5/24/2022 407,084
5/25/2022 391,378
5/26/2022 395,588
5/27/2022 387,512
5/28/2022 364,266
5/29/2022 343,718
5/30/2022 358,444
5/31/2022 415,572
6/1/2022 391,506
6/2/2022 421,750

Page 25 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
6/3/2022 387,944
6/4/2022 376,828
6/5/2022 369,913
6/6/2022 413,197
6/7/2022 381,400
6/8/2022 393,437
6/9/2022 425,181
6/10/2022 321,085
6/11/2022 313,178
6/12/2022 344,140
6/13/2022 437,785
6/14/2022 373,159
6/15/2022 339,710
6/16/2022 381,390
6/17/2022 408,535
6/18/2022 342,743
6/19/2022 339,425
6/20/2022 405,247
6/21/2022 379,806
6/22/2022 368,888
6/23/2022 374,000
6/24/2022 372,869
6/25/2022 317,234
6/26/2022 324,934
6/27/2022 387,107
6/28/2022 375,025
6/29/2022 376,290
6/30/2022 366,657
7/1/2022 406,743
7/2/2022 323,085
7/3/2022 315,340
7/4/2022 346,357
7/5/2022 411,731
7/6/2022 408,787
7/7/2022 419,057
7/8/2022 370,093
7/9/2022 337,194
7/10/2022 352,888
7/11/2022 420,612
7/12/2022 382,988
7/13/2022 380,062
7/14/2022 389,150
7/15/2022 324,287
7/16/2022 364,788
7/17/2022 325,675
7/18/2022 400,081
7/19/2022 392,219
7/20/2022 383,806
7/21/2022 370,944
7/22/2022 392,106
7/23/2022 339,925
7/24/2022 354,019
7/25/2022 381,569
7/26/2022 417,456
7/27/2022 389,663
7/28/2022 399,575
7/29/2022 378,268
7/30/2022 356,519
7/31/2022 369,994
8/1/2022 403,181
8/2/2022 426,325
8/3/2022 368,156
8/4/2022 324,050
8/5/2022 349,005
8/6/2022 338,105
8/7/2022 347,596
8/8/2022 297,895
8/9/2022 304,456
8/10/2022 167,125
8/11/2022 390,944

Page 26 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
8/12/2022 351,310
8/13/2022 324,330
8/14/2022 343,763
8/15/2022 367,595
8/16/2022 430,865
8/17/2022 327,828
8/18/2022 324,980
8/19/2022 306,059
8/20/2022 262,434
8/21/2022 257,371
8/22/2022 268,292
8/23/2022 304,686
8/24/2022 297,028
8/25/2022 286,939
8/26/2022 305,556
8/27/2022 252,858
8/28/2022 268,216
8/29/2022 292,654
8/30/2022 298,215
8/31/2022 292,000
9/1/2022 296,299
9/2/2022 306,621
9/3/2022 235,865
9/4/2022 237,366
9/5/2022 260,255
9/6/2022 282,911
9/7/2022 277,756
9/8/2022 297,989
9/9/2022 309,174
9/10/2022 258,772
9/11/2022 274,229
9/12/2022 274,770
9/13/2022 297,913
9/14/2022 271,269
9/15/2022 322,007
9/16/2022 283,719
9/17/2022 271,362
9/18/2022 298,075
9/19/2022 315,002
9/20/2022 305,254
9/21/2022 288,111
9/22/2022 304,769
9/23/2022 284,827
9/24/2022 252,032
9/25/2022 278,408
9/26/2022 296,369
9/27/2022 290,591
9/28/2022 283,201
9/29/2022
9/30/2022
10/1/2022 266,252
10/2/2022 284,550
10/3/2022 317,787
10/4/2022 316,272
10/5/2022 321,424
10/6/2022 320,433
10/7/2022 308,322
10/8/2022 278,628
10/9/2022 281,053
10/10/2022 289,007
10/11/2022 293,530
10/12/2022 332,945
10/13/2022 294,405
10/14/2022 293,564
10/15/2022 281,669
10/16/2022 299,866
10/17/2022 313,506
10/18/2022 325,562
10/19/2022 309,321
10/20/2022 326,790

Page 27 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
10/21/2022 307,678
10/22/2022 274,571
10/23/2022 281,454
10/24/2022 307,600
10/25/2022 271,382
10/26/2022 310,317
10/27/2022 296,894
10/28/2022 320,256
10/29/2022 254,547
10/30/2022 290,251
10/31/2022 323,289
11/1/2022 335,830
11/2/2022 351,931
11/3/2022 318,169
11/4/2022 316,572
11/5/2022 319,862
11/6/2022 318,629
11/7/2022 364,009
11/8/2022 530,594
11/9/2022 361,781
11/10/2022 344,207
11/11/2022 331,418
11/12/2022 290,044
11/13/2022 294,750
11/14/2022 326,156
11/15/2022 330,103
11/16/2022 333,353
11/17/2022 321,716
11/18/2022 326,762
11/19/2022 292,322
11/20/2022 309,747
11/21/2022 348,847
11/22/2022 341,531
11/23/2022 352,169
11/24/2022 266,331
11/25/2022 293,181
11/26/2022 290,713
11/27/2022 301,537
11/28/2022 330,632
11/29/2022 334,762
11/30/2022 335,056
12/1/2022 574,341
12/2/2022 377,250
12/3/2022 1,015,050
12/4/2022 632,497
12/5/2022 526,737
12/6/2022 453,050
12/7/2022 371,647
12/8/2022 416,928
12/9/2022 379,544
12/10/2022 1,337,988
12/11/2022 1,337,787
12/12/2022 653,360
12/13/2022 681,731
12/14/2022 388,422
12/15/2022 415,093
12/16/2022 401,988
12/17/2022 374,609
12/18/2022 394,607
12/19/2022 387,831
12/20/2022 411,265
12/21/2022 386,663
12/22/2022 404,703
12/23/2022 385,075
12/24/2022 352,366
12/25/2022 317,753
12/26/2022 454,306
12/27/2022 1,370,588
12/28/2022 640,537
12/29/2022 727,638

Page 28 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
12/30/2022 2,057,212
12/31/2022 1,662,733
1/1/2023 1,166,036
1/2/2023 990,525
1/3/2023 913,794
1/4/2023 825,312
1/5/2023 1,407,831
1/6/2023 1,154,582
1/7/2023 1,025,135
1/8/2023 1,227,827
1/9/2023 1,509,094
1/10/2023 1,287,631
1/11/2023 941,500
1/12/2023 744,381
1/13/2023 1,466,875
1/14/2023 2,130,232
1/15/2023 1,521,593
1/16/2023 1,603,325
1/17/2023 1,024,725
1/18/2023 829,019
1/19/2023 664,556
1/20/2023 580,888
1/21/2023 562,018
1/22/2023 529,225
1/23/2023 455,244
1/24/2023 507,425
1/25/2023 507,425
1/26/2023 449,325
1/27/2023 434,188
1/28/2023 404,187
1/29/2023 392,613
1/30/2023 398,893
1/31/2023 428,682
2/1/2023 392,631
2/2/2023 420,625
2/3/2023 407,350
2/4/2023 431,712
2/5/2023 489,613
2/6/2023 448,556
2/7/2023 453,431
2/8/2023 411,482
2/9/2023 417,087
2/10/2023 405,281
2/11/2023 369,744
2/12/2023 372,350
2/13/2023 366,544
2/14/2023 378,131
2/15/2023 353,925
2/16/2023 362,438
2/17/2023 359,493
2/18/2023 335,663
2/19/2023 354,487
2/20/2023 394,750
2/21/2023 380,813
2/22/2023 348,656
2/23/2023 378,063
2/24/2023 779,656
2/25/2023 601,737
2/26/2023 914,332
2/27/2023 1,387,218
2/28/2023
3/1/2023 1,004,413
3/2/2023 697,493
3/3/2023 612,105
3/4/2023 595,808
3/5/2023 862,405
3/6/2023 654,217
3/7/2023 612,267
3/8/2023 680,162
3/9/2023 1,272,686

Page 29 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
3/10/2023 1,636,981
3/11/2023 911,705
3/12/2023 852,385
3/13/2023 1,193,776
3/14/2023 1,581,664
3/15/2023 839,272
3/16/2023 676,145
3/17/2023 553,194
3/18/2023 514,082
3/19/2023 734,558
3/20/2023 684,725
3/21/2023 711,058
3/22/2023 760,066
3/23/2023 639,870
3/24/2023 579,913
3/25/2023 515,196
3/26/2023 509,883
3/27/2023 471,305
3/28/2023 855,556
3/29/2023 801,413
3/30/2023 685,729
3/31/2023 560,935
4/1/2023 435,400
4/2/2023 392,200
4/3/2023 368,800
4/4/2023 404,200
4/5/2023 376,200
4/6/2023 309,600
4/7/2023 326,400
4/8/2023 341,200
4/9/2023 273,000
4/10/2023 323,200
4/11/2023 338,600
4/12/2023 386,200
4/13/2023 298,400
4/14/2023 304,400
4/15/2023 253,600
4/16/2023 258,000
4/17/2023 294,400
4/18/2023 266,400
4/19/2023 287,400
4/20/2023 308,000
4/21/2023 272,400
4/22/2023 255,600
4/23/2023 280,400
4/24/2023 348,000
4/25/2023 299,800
4/26/2023 254,800
4/27/2023 299,200
4/28/2023 400,316
4/29/2023 239,800
4/30/2023 259,400
5/1/2023 254,600
5/2/2023 315,200
5/3/2023 289,400
5/4/2023 276,800
5/5/2023 303,000
5/6/2023 376,000
5/7/2023 293,000
5/8/2023 305,800
5/9/2023 308,400
5/10/2023 299,000
5/11/2023 292,800
5/12/2023 258,400
5/13/2023 215,200
5/14/2023 235,600
5/15/2023 286,800
5/16/2023 291,000
5/17/2023 285,400
5/18/2023 300,200

Page 30 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
5/19/2023 322,600
5/20/2023 297,000
5/21/2023 325,600
5/22/2023 286,800
5/23/2023 297,200
5/24/2023 329,400
5/25/2023 265,000
5/26/2023 261,400
5/27/2023 239,800
5/28/2023 231,800
5/29/2023 248,000
5/30/2023 264,000
5/31/2023 343,400
6/1/2023 325,200
6/2/2023 345,200
6/3/2023 325,800
6/4/2023 259,800
6/5/2023 278,600
6/6/2023 311,200
6/7/2023 318,800
6/8/2023 313,200
6/9/2023 354,400
6/10/2023 310,600
6/11/2023 315,400
6/12/2023 349,400
6/13/2023 304,000
6/14/2023 299,400
6/15/2023 348,400
6/16/2023 299,800
6/17/2023 266,600
6/18/2023 263,600
6/19/2023 304,400
6/20/2023 292,200
6/21/2023 313,000
6/22/2023 289,600
6/23/2023 309,200
6/24/2023 265,800
6/25/2023 281,200
6/26/2023 303,800
6/27/2023 324,600
6/28/2023 314,000
6/29/2023 321,000
6/30/2023 298,200
7/1/2023 241,400
7/2/2023 255,800
7/3/2023 288,200
7/4/2023 245,800
7/5/2023 307,200
7/6/2023 323,800
7/7/2023 319,200
7/8/2023 259,400
7/9/2023 270,200
7/10/2023 319,400
7/11/2023 300,400
7/12/2023 319,000
7/13/2023 310,400
7/14/2023 293,000
7/15/2023 276,800
7/16/2023 286,400
7/17/2023 327,800
7/18/2023 325,800
7/19/2023 300,400
7/20/2023 302,800
7/21/2023 318,000
7/22/2023 270,800
7/23/2023 289,200
7/24/2023 301,000
7/25/2023 306,400
7/26/2023 296,800
7/27/2023 308,400

Page 31 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
7/28/2023 303,000
7/29/2023 267,800
7/30/2023 273,200
7/31/2023 304,200
8/1/2023 290,800
8/2/2023 286,000
8/3/2023 296,000
8/4/2023 259,200
8/5/2023 286,200
8/6/2023 318,200
8/7/2023 336,000
8/8/2023 358,350
8/9/2023 385,425
8/10/2023 378,662
8/11/2023 353,788
8/12/2023 332,825
8/13/2023 338,800
8/14/2023 378,363
8/15/2023 378,363
8/16/2023 401,075
8/17/2023 355,650
8/18/2023 376,512
8/19/2023 320,800
8/20/2023 337,757
8/21/2023 362,168
8/22/2023 377,482
8/23/2023 354,637
8/24/2023 359,775
8/25/2023 326,881
8/26/2023 324,582
8/27/2023 329,843
8/28/2023 355,275
8/29/2023 345,082
8/30/2023 343,493
8/31/2023 369,644
9/1/2023 369,513
9/2/2023 326,625
9/3/2023 322,412
9/4/2023 350,219
9/5/2023 358,594
9/6/2023 384,312
9/7/2023 393,844
9/8/2023 373,031
9/9/2023 330,994
9/10/2023 324,681
9/11/2023 346,131
9/12/2023 410,394
9/13/2023 367,538
9/14/2023 395,925
9/15/2023 366,131
9/16/2023 329,431
9/17/2023 337,150
9/18/2023 375,000
9/19/2023 336,669
9/20/2023 354,794
9/21/2023 355,331
9/22/2023 364,544
9/23/2023 310,920
9/24/2023 313,092
9/25/2023 354,719
9/26/2023 152,456
9/27/2023 350,838
9/28/2023 362,006
9/29/2023 379,569
9/30/2023 357,618
10/1/2023 328,650
10/2/2023 371,857
10/3/2023 357,300
10/4/2023 331,900
10/5/2023 382,500

Page 32 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
10/6/2023 341,518
10/7/2023 339,182
10/8/2023 332,425
10/9/2023 366,537
10/10/2023 355,913
10/11/2023 340,081
10/12/2023 345,512
10/13/2023 406,375
10/14/2023 352,307
10/15/2023 339,981
10/16/2023 314,575
10/17/2023 350,287
10/18/2023 353,850
10/19/2023 353,007
10/20/2023 362,706
10/21/2023 328,937
10/22/2023 506,369
10/23/2023 392,419
10/24/2023 418,100
10/25/2023 396,216
10/26/2023 359,859
10/27/2023 368,548
10/28/2023 336,450
10/29/2023 325,877
10/30/2023 358,976
10/31/2023 350,410
11/1/2023 349,656
11/2/2023 386,860
11/3/2023 381,792
11/4/2023 342,374
11/5/2023 356,019
11/6/2023 392,784
11/7/2023 349,712
11/8/2023 340,591
11/9/2023 356,977
11/10/2023 345,601
11/11/2023 312,927
11/12/2023 978,804
11/13/2023 978,804
11/14/2023 346,300
11/15/2023 346,423
11/16/2023 366,622
11/17/2023 359,661
11/18/2023 379,770
11/19/2023 337,479
11/20/2023 323,533
11/21/2023 323,459
11/22/2023 353,200
11/23/2023 276,494
11/24/2023 349,589
11/25/2023 310,689
11/26/2023 310,469
11/27/2023 307,228
11/28/2023 340,780
11/29/2023 326,094
11/30/2023 311,853
12/1/2023 373,780
12/2/2023 312,299
12/3/2023 301,146
12/4/2023 313,904
12/5/2023 374,850
12/6/2023 330,667
12/7/2023 379,150
12/8/2023 318,986
12/9/2023 370,272
12/10/2023 300,353
12/11/2023 335,086
12/12/2023 307,483
12/13/2023 370,579
12/14/2023 400,929

Page 33 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
12/15/2023 385,392
12/16/2023 364,776
12/17/2023 304,889
12/18/2023 422,652
12/19/2023 421,495
12/20/2023 414,610
12/21/2023 350,150
12/22/2023 359,398
12/23/2023 325,638
12/24/2023 265,559
12/25/2023 234,094
12/26/2023 290,817
12/27/2023 307,976
12/28/2023 401,904
12/29/2023 387,304
12/30/2023 534,061
12/31/2023 295,246
1/1/2024 273,164
1/2/2024 483,243
1/3/2024 536,383
1/4/2024 415,064
1/5/2024 418,583
1/6/2024 392,136
1/7/2024 353,686
1/8/2024 343,916
1/9/2024 340,165
1/10/2024 364,006
1/11/2024 374,913
1/12/2024 356,625
1/13/2024 582,800
1/14/2024 483,900
1/15/2024 444,819
1/16/2024 570,618
1/17/2024 538,875
1/18/2024 478,391
1/19/2024 384,847
1/20/2024 535,591
1/21/2024 758,193
1/22/2024 818,591
1/23/2024 543,072
1/24/2024 566,200
1/25/2024 500,615
1/26/2024 420,860
1/27/2024 383,553
1/28/2024 387,366
1/29/2024 330,590
1/30/2024 354,338
1/31/2024 449,575
2/1/2024 734,827
2/2/2024 911,148
2/3/2024 662,887
2/4/2024 765,447
2/5/2024 797,644
2/6/2024 648,284
2/7/2024 818,903
2/8/2024 632,163
2/9/2024 597,144
2/10/2024 438,196
2/11/2024 418,891
2/12/2024 419,916
2/13/2024 404,978
2/14/2024 472,015
2/15/2024 458,629
2/16/2024 412,696
2/17/2024 489,907
2/18/2024 750,768
2/19/2024 858,460
2/20/2024 774,306
2/21/2024 708,300
2/22/2024 563,875

Page 34 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
2/23/2024 513,141
2/24/2024 453,909
2/25/2024 433,656
2/26/2024 448,275
2/27/2024 405,113
2/28/2024 396,119
2/29/2024 693,868
3/1/2024 1,520,063
3/2/2024 1,233,994
3/3/2024 1,156,906
3/4/2024 798,325
3/5/2024 664,225
3/6/2024 535,956
3/7/2024 500,600
3/8/2024 482,288
3/9/2024 447,937
3/10/2024 416,900
3/11/2024 430,063
3/12/2024 466,581
3/13/2024 409,294
3/14/2024 416,112
3/15/2024 390,319
3/16/2024 374,130
3/17/2024 387,676
3/18/2024 427,131
3/19/2024 414,757
3/20/2024 412,043
3/21/2024 394,913
3/22/2024 593,356
3/23/2024 667,988
3/24/2024 676,487
3/25/2024 540,838
3/26/2024 481,762
3/27/2024 488,575
3/28/2024 511,350
3/29/2024 578,200
3/30/2024 523,369
3/31/2024 420,000
4/1/2024 472,475
4/2/2024 473,312
4/3/2024 459,750
4/4/2024 640,463
4/5/2024 673,637
4/6/2024 492,794
4/7/2024 455,444
4/8/2024 129,200
4/9/2024 741,737
4/10/2024 420,132
4/11/2024 404,768
4/12/2024 407,069
4/13/2024 653,963
4/14/2024 501,925
4/15/2024 452,193
4/16/2024 428,200
4/17/2024 409,913
4/18/2024 395,044
4/19/2024 383,612
4/20/2024 354,000
4/21/2024 357,644
4/22/2024 382,481
4/23/2024 416,506
4/24/2024 406,569
4/25/2024 417,094
4/26/2024 369,919
4/27/2024 339,337
4/28/2024 331,156
4/29/2024 351,444
4/30/2024 409,563
5/1/2024 250,000
5/2/2024 204,400

Page 35 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
5/3/2024 247,600
5/4/2024 332,600
5/5/2024 256,400
5/6/2024 340,200
5/7/2024 464,400
5/8/2024 411,600
5/9/2024 379,000
5/10/2024 233,200
5/11/2024 279,400
5/12/2024 276,800
5/13/2024 235,200
5/14/2024 253,200
5/15/2024 292,400
5/16/2024 286,000
5/17/2024 240,000
5/18/2024 222,600
5/19/2024 271,000
5/20/2024 229,600
5/21/2024 295,800
5/22/2024 231,000
5/23/2024 1,371,400
5/24/2024 320,200
5/25/2024 275,200
5/26/2024 255,200
5/27/2024 340,000
5/28/2024 1,159,200
5/29/2024 222,200
5/30/2024 276,400
5/31/2024 420,000
6/1/2024 357,060
6/2/2024 329,509
6/3/2024 384,351
6/4/2024 388,477
6/5/2024 386,655
6/6/2024 372,454
6/7/2024 392,656
6/8/2024 329,524
6/9/2024 317,214
6/10/2024 353,788
6/11/2024 319,672
6/12/2024 358,449
6/13/2024 330,927
6/14/2024 281,070
6/15/2024 303,452
6/16/2024 285,869
6/17/2024 325,500
6/18/2024 321,651
6/19/2024 303,523
6/20/2024 368,003
6/21/2024 352,665
6/22/2024 295,968
6/23/2024 310,856
6/24/2024 354,438
6/25/2024 335,048
6/26/2024 329,302
6/27/2024 670,097
6/28/2024 297,337
6/29/2024 322,211
6/30/2024 329,786
7/1/2024 329,786
7/2/2024 339,692
7/3/2024 325,353
7/4/2024 323,780
7/5/2024 316,123
7/6/2024 293,202
7/7/2024 305,367
7/8/2024 318,019
7/9/2024 335,375
7/10/2024 374,305
7/11/2024 337,884

Page 36 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
7/12/2024 347,164
7/13/2024 294,373
7/14/2024 313,094
7/15/2024 323,982
7/16/2024 323,982
7/17/2024 332,486
7/18/2024 338,955
7/19/2024 345,831
7/20/2024 297,508
7/21/2024 306,319
7/22/2024 285,671
7/23/2024 313,341
7/24/2024 338,246
7/25/2024 319,393
7/26/2024 333,719
7/27/2024 297,572
7/28/2024 298,759
7/29/2024 322,761
7/30/2024 353,793
7/31/2024 335,279
8/1/2024 337,500
8/2/2024 320,636
8/3/2024 303,335
8/4/2024 296,478
8/5/2024 292,559
8/6/2024 338,372
8/7/2024 314,666
8/8/2024 303,796
8/9/2024 324,710
8/10/2024 344,862
8/11/2024 359,366
8/12/2024 344,050
8/13/2024 341,181
8/14/2024 350,203
8/15/2024 341,257
8/16/2024 294,968
8/17/2024 306,650
8/18/2024 323,035
8/19/2024 359,618
8/20/2024 362,507
8/21/2024 346,531
8/22/2024 332,459
8/23/2024 206,957
8/24/2024 248,371
8/25/2024 279,047
8/26/2024 325,313
8/27/2024 362,806
8/28/2024 382,816
8/29/2024 318,390
8/30/2024 311,982
8/31/2024 284,215
9/1/2024 283,072
9/2/2024 276,463
9/3/2024 349,118
9/4/2024 362,841
9/5/2024 327,491
9/6/2024 299,496
9/7/2024 266,019
9/8/2024 304,866
9/9/2024 317,990
9/10/2024 312,947
9/11/2024 283,641
9/12/2024 320,209
9/13/2024 291,066
9/14/2024 262,034
9/15/2024 286,750
9/16/2024 315,710
9/17/2024 306,706
9/18/2024 299,606
9/19/2024 307,391

Page 37 of 38 ends

Compiled Sutter Creek WWTP Daily Effluent Flow Data - Provided by ARSA Staff Date Sutter Creek
Effluent Flow
(GPD)
9/20/2024 310,740
9/21/2024 263,616
9/22/2024 262,938
9/23/2024 286,134
9/24/2024 312,700
9/25/2024 286,053
9/26/2024 284,784
9/27/2024 273,932
9/28/2024 252,803
9/29/2024 259,765
9/30/2024 294,210

Page 38 of 38 ends

www.hydroscience.com

ATTACHMENT B
Amador Regional Sanitation Agency
2024 Individual Water Balance Update
Draft 2023 Sutter Creek WWTP I/I Analysis Update
by Carollo Engineers
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pw://Carollo/Client/CA/Sutter Creek/12029A60/Deliverables/PM_I/I Analysis Update/PM_IIAnalysisUpdate DRAFT / 1

PROJECT MEMORANDUM

CITY OF SUTTER CREEK
Wastewater Treatment Plant Upgrade Project
Project No.:

Date:

Prepared By:
12029A60
October 10, 2023
Michael Wetterau, PE
Reviewed By: Ryan Orgill, PE; Louis Lefebvre, PE; Christina Romano, PE Subject: Infiltration and Inflow Analysis Update
Background and Purpose
As part of the 2020 to 2021 Project Report efforts, Carollo Engineers (Carollo) developed a simple model of the collection system to estimate wet weather flow (WWF) design criteria. This information was used to conceptually size project alternative facilities evaluated in the Project Report. A typical peak wet weather flow (PWWF) factor ranges from three to six times the average daily flow (ADF). By comparison the City of Sutter Creek’s (City’s) PWWF is approximately 16, an order of magnitude higher than typical.

The City has been implementing infiltration and inflow (I/I) mitigation projects with the goal of reducing I/I impacts on its wastewater system. In the winter of 2023, the City performed sewer flow monitoring to help determine the areas with the highest I/I flows to further focus I/I reduction efforts. Some of the most common sources of I/I are shown on Figure 1.

Carollo was asked to review the data collected and incorporate it into the wastewater treatment plant (WWTP) project rescoping efforts. This memorandum includes the following:
▪ Verification of existing WWF factors.
▪ Identification of potential priority zones within the existing wastewater collection system for potential future I/I reduction projects.
▪ Development of ranges of possible WWF reduction if I/I reduction projects are implemented.

These three items are important because they could affect the size and cost of the WWTP upgrade project, as well as optimize the value of any future I/I reduction efforts. WWF factors could be used to size pumping facilities, sewage screens and grinders (i.e., headworks facilities, equalization tanks and sewer pipes). With lower WWFs, these facilities could be smaller and less costly. Understanding the areas that could be prioritized for I/I mitigation projects will increase the value of resources spent on those projects while decreasing the amount of time to observe benefits (i.e., reduced WWFs). Furthermore, I/I mitigation projects have the potential to increase the service life of existing sewers without costly replacement.

Lastly, understanding the range of WWF reduction the City could see by undertaking future I/I reduction projects sets the level of expected benefit. The analysis considered historical WWTP influent flow along with temporary flow monitoring data to determine the expected WWTP influent flow during a design storm event.
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Figure 1 Typical Sources of I/I
Methods
Historical influent plant data was used to determine the dry weather flow (DWF) and WWF conditions during the monitoring period. A hydraulic model was developed using InfoSWMM1to model the influent flow at the WWTP for historical events. The hydraulic model’s parameters were adjusted to match historical flow monitoring data.

For this project, DWF monitoring was determined based on historical plant data. Figure 2 shows the weekday and weekend hourly DWF multipliers for the entire system. A multiplier equal to 0.5 indicates at that hour of the day the flow is equal to one-half of the ADF. 1 InfoSWMM is a fully dynamic, geospatial wastewater and stormwater modeling and management software application, which is built to run within the ESRI ArcGIS software platform. The hydraulic modeling engine for the InfoSWMM software package uses the Environmental Protection Agency’s (EPA) Storm Water Management Model (SWMM), which is widely used throughout the world for planning, analysis, and design related to stormwater runoff, combined sewers, sanitary sewers, and other drainage systems. InfoSWMM routes flows through the model using the Dynamic Wave method, which solves the complete Saint Venant, one dimensional equations of fluid flow. 305
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Figure 2 Weekday and Weekend DWF Hourly Multiplier
The WWF calibration consists of using actual influent WWTP flow data recorded during wet weather events, for which we have rainfall data, and adjusting model parameters so that the modeled flows match the actual flows. The model parameters are discussed later. The WWF calibration consisted of five periods with storm events. The amount of I/I is essentially the difference between the WWF and DWF components. The storm events were identified between the following dates:
▪ Period 1: January 2, 2017, through January 15, 2017.
▪ Period 2: February 5, 2017, through February 12, 2017. ▪ Period 3: March 12, 2018, through March 24, 2018.
▪ Period 4: March 1, 2019, through March 8, 2019.
▪ Period 5: March 9, 2023, through March 16, 2023.

The main step in the WWF calibration process includes creating a custom unit hydrograph for the City service area using the “RTK Method,” which is widely used in collection system master planning. Using the RTK Method, the I/I unit hydrograph is the summation of three separate triangular hydrographs (short term, medium term, and long term), which are each defined by three parameters: R, T, and K. R represents the fraction of rainfall over the sewer basin that enters the collection system; T represents the time to peak of the hydrograph; K represents the ratio from time to peak to time of end of hydrograph. Therefore, there are a total of nine separate variables associated with a unit hydrograph. Figure 3 shows the shape of an example unit hydrograph. The WWF calibration sheets show figures comparing the measured data and model results for flow in response to rainfall. The WWF calibration sheets are included in Attachment A. 306
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Figure 3 Example Rainfall Dependent Infiltration and Inflow (RDII) Unit Hydrograph Design Storm
Design storms are rainfall events used to analyze the performance of a collection system under select wet weather events. The City’s design storm was routed through the collection system model to determine PWWFs. The first step in the development of the design storm is to define its recurrence interval and rainfall duration. The recurrence interval is based on the probability that a given rainfall event will occur or be exceeded in any given year. For example, a “100-year storm” means there is a 1 in 100 chance that a storm as large as or larger than this event will occur at a specific location in any year.

Duration is the length of time in which the rainfall occurs. It is industry standard in California to use the 10-year, 24-hour design storm for analyzing wastewater collection system performance during PWWF conditions and for sizing some WWTP facilities (e.g., equalization tanks and pump stations). The 10-year, 24-hour design storm depth is 3.98 inches as document by National Oceanic and Atmospheric Administration (NOAA) Atlas 14.

Once the design storm recurrence interval, duration, and associated rainfall volume have been determined, the next step in defining the design storm is to distribute the total rainfall over the duration of the storm. The Natural Resources Conservation Service (NRCS) Type 1A rainfall distribution was used.

Figure 4 shows the 10-year, 24-hour design storm.
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Figure 4 10-year 24-hour Design Storm Event
Hydraulic Evaluation
Following the DWF and WWF calibration of the model the design storm was applied to forecast sewer flow. The hydraulic analysis assumes all flow is conveyed to the WWTP and no flow is restricted or escapes the collection system. Figure 5 shows the peak influent flow based on the design storm at the WWTP. The model predicts that a peak hour WWF of 5.36 million gallons per day (mgd) could be observed if there were no restrictions in the collection system and if no wastewater escapes the collection system.

Additionally, the model predicts that a peak day WWF of 3.16 mgd could be observed at the WWTP as a result of the 10-year, 24-hour design storm event.

Figure 5 Modeled Influent PWWF - 10-year, 24-hour Design Storm 308
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Temporary Flow Monitoring Program
The City completed a temporary flow monitoring program between March 8, 2023, and April 6, 2023. The flow monitoring program consisted of ten flow meters installed throughout the collection system in hopes of identifying areas in the collection system with high amounts of I/I. Table 1 summarizes the measured flow data.

Table 1 Temporary Flow Monitoring Data Summarized
Basin Measured DWF (mgd) Measured Peak Flow (mgd) Peaking Factor Pipe Length (feet) 1 0.04 0.17 4.1 0
2 0.23 1.97 8.5 18,670
3 0.07 0.16 2.3 8,010
4 0.07 0.21 3.1 7,000
5 0.01 0.13 17.9 2,960
6 0.01 0.12 9.6 3,470
7 0.18 0.76 4.1 14,480
8 0.07 0.33 5.0 4,300
9 0.08 0.46 5.5 7,020
10 0.02 0.10 5.4 10,900
Notes:
(1) Source: Flow monitoring program March 8, 2023, through April 6, 2023.

I/I Reduction
The adverse effects of I/I are that it increases both the flow volume and peak flow rate. If the City were to implement an I/I reduction program this may allow for reducing the size of some WWTP facilities (e.g., pump stations and equalization tanks). An efficient I/I reduction program will target rehabilitating the portions of the sewer collection system with the highest I/I rates. The City’s sewer collection system was broken down into portions, referred to as basins (see Figure 6). I/I rates within the different basins were calculated per length of pipe in that basin. Basins 5, 6, 8, and 9 have the highest I/I rates per foot of sewer pipe and could be targeted for I/I reduction efforts. Collectively these basins account for approximately 18 percent of the total sewer collection system by length. 309
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Figure 6 Meter Basins Map
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There are a variety of I/I reduction techniques that can be used. I/I reduction projects can range from manhole rehabilitation to sewer main replacement/rehabilitation and lateral rehabilitation. Implementing an I/I reduction program is no guarantee that the desired I/I reduction will be achieved. However, there is a baseline benefit to rehabbing existing facilities because it would extend their life. For this analysis 30 percent and 65 percent I/I reduction in the selected basins was assumed to estimate the potential reduction in peak flows. Table 2 summarizes the potential reduction of peak influent flow at the WWTP for the range of I/I reduction assumed. Based on a review of historical literature and Carollo’s experience in order to achieve an I/I reduction of 65 percent, the City may need to incorporate pipe, manhole, and service laterals rehabilitation.

Table 2 Peak Influent Flows
Scenario Peak Influent Flow (mgd)
No Reduction 5.36
30% Reduction in Basins 5, 6, 8, and 9 4.74
65% Reduction in Basins 5, 6, 8, and 9 4.03
Conclusion
This memorandum verified existing WWFs, identified basins with highest I/I, and identified potential reductions in WWFs if I/I reduction projects are implemented in the priority basins. The planned WWTP upgrade project could expect a peak hour flow of 5.36 mgd and a peak day flow of 3.16 mgd as a result of the 10-year, 24-hour design storm.

Basins 5, 6, 8, and 9 could be prioritized for I/I reductions because I/I rates are highest in these basins.

Approximately 18 percent of the total sewer collection system length is in these basins. If I/I is reduced in these basins between 30 percent and 65 percent a reduction in peak hour flow between 0.62 mgd and

1.33 mgd could be realized.
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ATTACHMENT C
Amador Regional Sanitation Agency
2024 Individual Water Balance Update
ARSA Storage Reservoirs Supporting Documentation
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HENDERSON RESERVOIR AERIAL TOPOGRAPHIC SURVEY DATA

PROVIDED BY ARSA STAFF AND GARY GHIO

SITE PLAN
PROJECT No.: 2457
PROJECT NAME:

Weber, Ghio & Associates, Inc.

Professional Engineers
394 East Saint Charles P.O. Box 251 SAN ANDREAS, CALIFORNIA 95249

HENDERSON RESERVOIR

RUNOFF AREA
0 300 600
WATERSHED RUNOFF AREA, (4.3 ACRES)
LEGEND:
76 315
Section 13, Item J.

SITE PLAN
0 300 600
PROJECT No.: 2457
PROJECT NAME:

Weber, Ghio & Associates, Inc.

Professional Engineers
394 East Saint Charles P.O. Box 251 SAN ANDREAS, CALIFORNIA 95249

PRESTON RESERVOIR

RUNOFF AREA
WATERSHED RUNOFF AREA, (14.0 ACRES)
LEGEND:
77 316
Section 13, Item J.

Dam Information Summary
Preston Dam, No. 2029.003, Area 6, Amador County
State of California
California Natural Resources Agency

DEPARTMENT OF WATER RESOURCES
Division of Safety of Dams
Quad Book 2C-37A3
Quad Map IONE
Latitude 38.3698°
Longitude -120.9398°
Stream Tr Mule Creek
Tributary To
Year Built 1949
Parapet Code None
Total Freeboard, Ft 5.00
Oper. Freeboard, Ft 5.00
National Forest N.I.N.F.

NID Number CA00012
FERC Number
Fed. Hazard Class Significant
Hazard Class 2B
Total Class Weight 14
Barrier Height, Ft 35.00
Crest Elevation, Ft 360.00
Crest Width, Ft 20.00
Dam Height, Ft 40.00
Dam Length, Ft 647.00
Volume, CY 86,519.00
MPWS Elev., Ft 355.00
MPWS Capacity, AF 268.00
Use(s) SEW, IRR
Purpose(s) STO
Dam Dimensions
Parapet Height, Ft 0.00
Location
Dam Information
Status Certified
Exempt Desc. (Unselected)
Issue Date 10/6/1980
Max Cert. Elev., Ft 355.00
Type Earth
US Public Land Survey System
Hazard Potential
Jurisdiction
Certificate Information
Hydrology
Seismic Parameters
Restrictions
Restriction None
Reason
Restricted Elev., Ft
Start Date
Outlet Works
Attributes
No
No
Inoperable
Receives Spillway Letter
Instrumentation No
Reservoir
Name Primary Reservoir
Surface Area, Ac 17.00
at Cert Elev. 268.00
at Dam Crest 0.00
at SW Crest 0.00
Storage Capacities, AF
Primary Spillway
Crest Elev, Ft 355.00
Type (Unselected)
Estimate Date 8/18/1948
Drainage Area, Sq Mi 0.12
Mean Annual Precip, In 0.00
Est. Type DWR
Peak Inflow, cfs
Peak Outflow, cfs
Residual Freeboard, Ft 0.00
Max Stage, Ft
Type
Short Term
Long Term
Estimate Date
Fault
Max Magnitude
Shear Wave Vel., m/s
Peak Ground Acc., g
Arias Intensity, m/s
Deterministic Level
Drawdown Estimates, Days
-¼, S24, T6N, R9E, MD B&M
Duration
Gates Ungated
Duration Year Round
Amador Regional Sanitation Authority
Printed: Tuesday, February 28, 2017, by: Dhillon, Param 110
317
Section 13, Item J.

Dam Information Summary
Preston Forebay Dam, No. 2029.002, Area 6, Amador County State of California
California Natural Resources Agency

DEPARTMENT OF WATER RESOURCES
Division of Safety of Dams
Quad Book 2C-37A1
Quad Map IRISH HILL
Latitude 38.3754°
Longitude -120.9233°
Stream Offstream
Tributary To
Year Built 1892
Parapet Code None
Total Freeboard, Ft 4.00
Oper. Freeboard, Ft 4.00
National Forest N.I.N.F.

NID Number CA00006
FERC Number
Fed. Hazard Class Low
Hazard Class 1C
Total Class Weight 6
Barrier Height, Ft 36.00
Crest Elevation, Ft 624.00
Crest Width, Ft 0.00
Dam Height, Ft 40.00
Dam Length, Ft 176.00
Volume, CY 22,400.00
MPWS Elev., Ft 620.00
MPWS Capacity, AF 30.00
Use(s) SEW, IRR
Purpose(s) REG
Dam Dimensions
Parapet Height, Ft 0.00
Location
Dam Information
Status Certified
Exempt Desc. (Unselected)
Issue Date 10/6/1980
Max Cert. Elev., Ft 620.00
Type Earth
US Public Land Survey System
Hazard Potential
Jurisdiction
Certificate Information
Hydrology
Seismic Parameters
Restrictions
Restriction None
Reason
Restricted Elev., Ft
Start Date
Outlet Works
Attributes
No
No
Inoperable
Receives Spillway Letter
Instrumentation No
Reservoir
Name Primary Reservoir
Surface Area, Ac 2.00
at Cert Elev. 30.00
at Dam Crest 0.00
at SW Crest 0.00
Storage Capacities, AF
Primary Spillway
Crest Elev, Ft 620.00
Type (Unselected)
Estimate Date 4/19/1940
Drainage Area, Sq Mi 0.00
Mean Annual Precip, In 0.00
Est. Type 1000
Peak Inflow, cfs 20.00
Peak Outflow, cfs 20.00
Residual Freeboard, Ft 2.20
Max Stage, Ft 2.20
Type
Short Term
Long Term
Estimate Date
Fault
Max Magnitude
Shear Wave Vel., m/s
Peak Ground Acc., g
Arias Intensity, m/s
Deterministic Level
Drawdown Estimates, Days
-¼, S18, T6N, R10E, MD B&M
Duration
Gates Ungated
Duration Year Round
Amador Regional Sanitation Authority
Printed: Tuesday, February 28, 2017, by: Dhillon, Param 111
318
Section 13, Item J.

Dam Information Summary
Henderson Dam, No. 2029.000, Area 6, Amador County
State of California
California Natural Resources Agency

DEPARTMENT OF WATER RESOURCES
Division of Safety of Dams
Quad Book 2C-37A1
Quad Map IRISH HILL
Latitude 38.3856°
Longitude -120.8771°
Stream Jackass Creek
Tributary To
Year Built 1923
Parapet Code None
Total Freeboard, Ft 3.00
Oper. Freeboard, Ft 3.00
National Forest N.I.N.F.

NID Number CA00005
FERC Number
Fed. Hazard Class Significant
Hazard Class 2B
Total Class Weight 12
Barrier Height, Ft 53.00
Crest Elevation, Ft 86.50
Crest Width, Ft 8.00
Dam Height, Ft 56.00
Dam Length, Ft 630.00
Volume, CY 70,000.00
MPWS Elev., Ft 83.50
MPWS Capacity, AF 500.00
Use(s) SEW, IRR
Purpose(s) STO
Dam Dimensions
Parapet Height, Ft 0.00
Location
Dam Information
Status Certified
Exempt Desc. (Unselected)
Issue Date 10/6/1980
Max Cert. Elev., Ft 83.50
Type Earth
US Public Land Survey System
Hazard Potential
Jurisdiction
Certificate Information
Hydrology
Seismic Parameters
Restrictions
Restriction None
Reason
Restricted Elev., Ft
Start Date
Outlet Works
Attributes
No
No
Inoperable
Receives Spillway Letter
Instrumentation No
Reservoir
Name Primary Reservoir
Surface Area, Ac 31.00
at Cert Elev. 500.00
at Dam Crest 595.00
at SW Crest 500.00
Storage Capacities, AF
Primary Spillway
Crest Elev, Ft 83.50
Type Sharp Crested Weir
Estimate Date 5/2/1971
Drainage Area, Sq Mi 1.00
Mean Annual Precip, In 0.00
Est. Type 1000
Peak Inflow, cfs 752.00
Peak Outflow, cfs 489.00
Residual Freeboard, Ft 1.30
Max Stage, Ft 785.30
Type
Short Term
Long Term
Estimate Date
Fault
Max Magnitude
Shear Wave Vel., m/s
Peak Ground Acc., g
Arias Intensity, m/s
Deterministic Level
Drawdown Estimates, Days
-¼, S9, T6N, R10E, MD B&M
Duration
Gates Ungated
Duration Year Round
Amador Regional Sanitation Authority
Printed: Tuesday, February 28, 2017, by: Dhillon, Param 112
319
Section 13, Item J.

Cumulative Cumulative Incremental
Elev Area Volume Volume Volume Volume Increase
(ft) (ac) (ac-ft) (ac-ft) (MG) (ac-ft)
780 30.06 14.96 451.83 147.22 14.96 Spillway
779.5 29.80 14.84 436.86 142.34 14.84
779 29.57 14.70 422.02 137.51 14.70
778.5 29.22 14.53 407.33 132.72 14.53
778 28.88 14.34 392.80 127.99 14.34 2 ' Freeboard
777.5 28.47 14.14 378.46 123.31 14.14
777 28.07 13.92 364.33 118.71 13.92
776.5 27.62 13.70 350.41 114.17 13.70
776 27.17 13.47 336.71 109.71 13.47
775.5 26.69 13.23 323.24 105.32 13.23
775 26.23 12.97 310.01 101.01 12.97
774.5 25.67 12.69 297.04 96.78 12.69
774 25.11 12.39 284.34 92.65 12.39
773.5 24.46 12.10 271.95 88.61 12.10
773 23.96 11.83 259.84 84.66 11.83
772.5 23.34 11.53 248.02 80.81 11.53
772 22.78 11.20 236.49 77.05 11.20
771.5 22.01 10.86 225.29 73.41 10.86
771 21.41 10.54 214.44 69.87 10.54
770.5 20.73 10.18 203.90 66.44 10.18
770 19.99 9.85 193.72 63.12 9.85
769.5 19.40 9.55 183.87 59.91 9.55
769 18.79 9.24 174.33 56.80 9.24
768.5 18.17 8.94 165.09 53.79 8.94
768 17.57 8.64 156.15 50.88 8.64
767.5 16.97 8.33 147.51 48.06 8.33
767 16.34 8.03 139.19 45.35 8.03
766.5 15.79 7.79 131.15 42.73 7.79
766 15.36 7.57 123.37 40.20 7.57
765.5 14.93 7.36 115.80 37.73 7.36
765 14.52 7.16 108.43 35.33 7.16
764.5 14.11 6.96 101.28 33.00 6.96
764 13.73 6.74 94.32 30.73 6.74
763.5 13.25 6.53 87.57 28.53 6.53
763 12.86 6.34 81.05 26.41 6.34
762.5 12.51 6.16 74.71 24.34 6.16
762 12.13 5.91 68.55 22.34 5.91
761.5 11.52 5.67 62.64 20.41 5.67
761 11.15 5.47 56.97 18.56 5.47
760.5 10.75 5.26 51.50 16.78 5.26
760 10.30 5.03 46.23 15.06 5.03
759.5 9.83 4.80 41.20 13.42 4.80
759 9.37 4.57 36.40 11.86 4.57
758.5 8.91 4.35 31.83 10.37 4.35
4/21/2015

HENDERSON RESERVOIR VOLUME

AMADOR REGIONAL SANITATION AUTHORITY
114

HENDERSON RESERVOIR STAGE-STORAGE DATA

BASED ON AERIAL TOPOGRAPHIC SURVEY DATA

PROVIDED BY ARSA STAFF AND GARY GHIO
320
Section 13, Item J.
758 8.48 4.12 27.48 8.96 4.12
757.5 8.00 3.89 23.36 7.61 3.89
757 7.57 3.65 19.47 6.34 3.65
756.5 7.03 3.40 15.82 5.16 3.40
756 6.59 3.15 12.42 4.05 3.15
755.5 6.01 2.88 9.27 3.02 2.88
755 5.49 2.55 6.39 2.08 2.55
754.5 4.70 2.20 3.85 1.25 2.20
754 4.12 1.34 1.64 0.54 1.34
753.5 1.23 0.31 0.31 0.10 0.31
753 0 0.00 0.00 0.00 0.00
* spillway elevation = 780'
Volume established from 11-07-08 aerial topo
115
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Preston Reservoir
Elevation Area Capacity Elevation
(AC) (AC-FT)
325 0 0 325
330 3 5 330
335 6 25 335
340 8 60 340
345 12 110 345
350 16 175 350
353 18 235 353 2' Freeboard
355 20 270 355 Spillway
116

PRESTON RESERVOIR STAGE-STORAGE DATA

PROVIDED BY ARSA STAFF AND GARY GHIO
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ATTACHMENT D
Amador Regional Sanitation Agency
2024 Individual Water Balance Update
City of Ione Response to February 3, 2025, Review Letter and 2024 COWRF Capacity and Operations TM
by West Yost Engineers
323
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City of Ione
P.O. Box 398
1 E. Main Street
Ione, CA 95640
February 24, 2024 SENT VIA: EMAIL
Kari Holmes, P.E.

Supervising Water Resources Control Engineer
Central Valley Regional Water Quality Control Board
11020 Sun Center Drive, #200
Rancho Cordova, CA
[email protected]
Subject: Certification Letter for Castle Oaks Golf Course Recycled Water Demands Dear Ms. Holmes,
On August 14, 2024, the Central Valley Water Quality Control Board (Regional Board) issued a 13267 Order letter to the City of Ione (City), Amador Regional Sanitation Agency (ARSA) and Portlock International Ltd. (Portlock), the three entities permitted the Regional Board under Water Reclamation Requirement Order 93-240 (WRRs) to land apply recycled water from the Castle Oaks Water Reclamation Facility (COWRF) to the Castle Oaks Golf Course (golf course).

The City owns and operates the COWRF, which provides the recycled water to the golf course.

The City also owns the golf course, which is leased and operated by Portlock. ARSA is permitted to supply water to the COWRF to meet the irrigation needs of the golf course.

The 13267 Order requires that the three WRRs permittees submit an updated water balance for the ARSA system to the Regional Board by December 13, 2024. Most of the required information under the 13267 Order does not pertain to the COWRF or golf course operations.

Consequently, ARSA lead the development of the response required under the 13267 Order.

To address requirements specific to the City-led operations, the City previously submitted the Castle Oaks Golf Course Recycled Water Demands Technical Memorandum (Water Demands TM) that provided information and supporting documentation for the following topics:
• Historical and theoretical influent flows to the COWRF, • Historical and theoretical recycled water use at the Golf Course, • Agronomic water demands of the Golf Course,
• Storage capacity and operation of the Golf Course recycled water storage ponds, and 325
Section 13, Item J.
• Golf Course tailwater and overspray control and monitoring – including BMPs to minimize runoff or overspray and practices to improve the application of recycled water to the use area.

On February 3, 2025, the Regional Board issued a letter titled Review of Site-Specific Water Balance, Amador County Regional Outfall And Castle Oaks Golf Course And Development, City Of Ione/Amador Regional Sanitation Authority/Portlock Int. LLC., WDR 93-240, Amador County. This letter documented additional information that must be addressed in the site-specific water balance. The specific items identified that apply to the City’s operation and the City’s response to these items are summarized in the table below.

Summary of Responses to Regional Board Comments
Regional Board Comment City Response
The City of Ione is currently
developing a Title 22 Engineering
Report for the use of recycled
water produced at the COWRF on
the COGC. Title 22 requires
setbacks for the irrigation of
recycled water near water
courses, residential areas, and
public spaces. It is unclear if the
acreage used to calculate the
COGC disposal capacity
considers these setbacks. More
information shall be submitted,
and the water balance shall be
updated accordingly as needed.

Title 22 includes the following setback distance
requirements applicable to disinfected tertiary recycled water:
• No irrigation with disinfected tertiary recycled
water shall take place within 50 feet of any
domestic water supply well.
• No impoundment of disinfected tertiary recycled
water shall occur within 100 feet of any domestic
water supply well.
• Any use of recycled water shall comply with the
following:
- Any irrigation runoff shall be confined to the
recycled water use area, unless the runoff does
not pose a public health threat and is authorized
by the regulatory agency.
- Spray, mist, or runoff shall not enter dwellings,
designated outdoor eating areas, or food
handling facilities.
- Drinking water fountains shall be protected
against contact with recycled water spray, mist,
or runoff.

As part of development of the Title 22 Report, the City’s consultant team West Yost Associates comprised of crossconnection control specialists conducted surveys of the golf course to confirm setback distance requirements were being satisfied. The irrigated acreages used in the water balances were developed from the information obtained
during this survey.

There are no known domestic water supply wells within
50-feet of the use area (or within 100 feet of the irrigation impoundments). The team also observed spray irrigation
practices and confirmed there was no evidence of spray
mist or runoff entering enter dwellings, designated
326
Section 13, Item J.

Summary of Responses to Regional Board Comments
Regional Board Comment City Response
outdoor eating areas, or food handling facilities or
drinking fountains.

Based on this information, the setback distances do not need to be modified to meet the requirements of Title 22.

The existing irrigated acreages used in the water balances were developed from the information obtained during this survey. These acreages do not need to be modified to
conform to Title 22.

Additional details will be included in the Title 22 Report.

No change is required to address this statement.

The submittal indicates that
COGC has an “overflow” from
one of the recycled water holding
ponds into Mule Creek. This is an
unpermitted discharge and cannot
be used as part of the water
balance. The submittal also states
“In addition, the recycled water
remaining in Lake I at the end of
the irrigation season is diluted
with 1.2 million gallons of
potable water. Golf course staff
reported that this practice was
developed in partnership with the
California Department of Health
Services to minimize the potential
for discharge of recycled water to
surface waters.” No such practice
has been permitted by the
Department of Health Services
(now the Division of Drinking
Water, or DDW) nor the Central
Valley Water Board. It is
inaccurate to state that the
Discharger believed this to be an
approved discharge, as an NOV
was issued for the same discharge
on 28 January 2020. This
discharge must cease
immediately, the water balance
shall be updated appropriately.

The City understands the Board’s direction that the “dual use” of the ponds on the golf course is not an approved discharge and must cease. Importantly, for purposes of
addressing comments on the updated water balance for the ARSA system, discharge from these ponds was not
accounted for in the City’s water balance. Accordingly, no revision is required to the water balance to address the Regional Board’s comment.

Moving forward, the City will reach out to and coordinate with the Regional Board, DDW, and the golf course to take action to address the prohibited discharge. Development of such action(s) may be appropriate as part of the
preparation and finalization of the City’s Title 22 Report. 327
Section 13, Item J.
“I certify under penalty of law that I have personally examined and am familiar with the information submitted in this letter and that, based on my inquiry of those individuals immediately responsible for obtaining the information, I believe that the information is true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment.” Sincerely,
George Lee, City Manager
CC:

Mr. Kenny Croyle, PE
Water Resources Control Engineer
Central Valley Regional Water Quality Control Board
[email protected]
Mr. Howard Hold
Senior Engineering Geologist
Central Valley Regional Water Quality Control Board
[email protected]
Mr. Scott Armstrong
Senior Engineering Geologist
Central Valley Regional Water Quality Control Board
[email protected]
328
Section 13, Item J.
329
Section 13, Item J.
330
Section 13, Item J.
1001 Galaxy Way
Suite 310
Concord CA 94520
925.949.5800 phone
925.949.5845 fax
westyost.com

TECHNICAL MEMORANDUM
DATE: December 9, 2024 Project No.: 988-50-24-10
SENT VIA: EMAIL
TO: George Lee, City of Ione
FROM: Ileana Wald, PE, RCE #97046
REVIEWED BY: Kathryn Gies, PE, RCE #65022
SUBJECT: Castle Oaks Water Reclamation Facility Capacity and Operations Summary This technical memorandum (TM) provides information and supporting documentation related to the capacity and operations of the Castle Oaks Water Reclamation Facility (COWRF), which is owned and operated by the City of Ione (City). The purpose of this TM is to inform development of a water balance for the Amador Regional Sanitation Authority (ARSA) wastewater disposal system. The following topics are addressed:
• Background Information
• Treatment Facilities Description
• Recycled Water Treatment Operations
• Treatment Capacity Summary

BACKGROUND INFORMATION
Facility Overview
The COWRF is a tertiary-only recycled water treatment plant located at 10100 Five Mile Drive in Ione, Amador County, California (see Figure 1, Vicinity Map). The facility receives disinfected secondary treated wastewater that is further treated through coagulation, filtration, and chlorine disinfection processes. A schematic diagram, hydraulic profile and design criteria for the COWRF that were included in the As-Built drawing set are included as Attachment A.

The COWRF produces “Disinfected Tertiary Recycled Water” as defined under the California Code of Regulations (CCR), Title 22 for irrigation use at the Castle Oaks Golf Course (golf course), which is leased and operated by Portlock International Ltd. (Portlock). There are no other uses or use areas. The City’s Wastewater Treatment Facility (WWTF) is located adjacent to the COWRF but does not presently send treated effluent to the COWRF for treatment.
331
Section 13, Item J.

City of Ione Wastewater Treatment Plant
Castle Oaks Water Reclamation Facility
5 Mile Drive
Prepared by: Prepared for:

Figure 1
WEST YOST - N:\Clients\988 City of Ione\50-24-10 As Needed\GIS\MXD\Vicinity Map.mxd - aguillebeau - 11/20/2024 0 200 400
Feet
City of Ione
Capacity and Operations TM
Vicinity Map
WWTP Boundary
COWRF Boundary
332
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December 9, 2024

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N-C-988-50-24-10-WP-CAPACITY AND OPERATIONS TM
Regulatory History
The City, ARSA and Portlock are the three entities permitted the Central Valley Water Quality Control Board (Regional Board) under Water Reclamation Requirement Order 93-240 (WRRs) to discharge recycled water from the COWRF to the golf course. ARSA is specifically permitted to supply secondary treated wastewater to the COWRF to meet the irrigation needs of the golf course.

On August 14, 2024, the Regional Board issued a 13267 Order letter to the three WRRs permittees that requires the submission of an updated water balance for the ARSA system to the Regional Board by December 13, 2024. The letter specifies six items (A through F) that must be provided. This TM addresses the requirements under Item D of this letter, which states the following information must be provided:

The current and expected treatment capacity and operation schedule of the tertiary treatment plant. These numbers should be provided and certified by Ione. Supporting documentation must be included.

TREATMENT FACILITIES DESCRIPTION
The treatment process train consists of preliminary screening, chemical coagulation, direct sand filtration, and chlorine disinfection. The layout of COWRF’s treatment facilities are shown on Figure 2. The major treatment components of the COWRF include:
• Influent flow control and screening,
• Coagulation/flocculation,
• Filtration,
• Chlorine disinfection,
• Effluent pumping, and
• Solids treatment and handling.

Influent Flow Control and Screening
The COWRF headworks structure includes a magnetic flow meter, a pneumatically operated butterfly valve for flow control, screens, and an influent sample tap. The flow through the COWRF is controlled by the butterfly control valve and is based on an operator-set target flow rate. The flow rate is set to match the demand from the golf course. The valve will shut automatically in the event of a critical process failure (high liquid levels, high turbidity, or low chlorine residual) or power outage.

One static parabolic screen is provided to remove large solids prior to filtration. The screen opening size is 0.10 inch and the stated capacity of the screen is 1,350 gallons per minute (gpm).

Coagulation/Flocculation
Screened recycled water flows by gravity to the rapid mix chamber. Alum and/or polymer are added downstream of the static screen and prior to rapid mixer that promotes coagulation of the solids.

Additional polymer can also be added before recycled water flows through two mechanical flocculation chambers. The signal from the influent flow meter is used to automatically flow pace the alum and polymer metering pumps to achieve a desired dosing rate. Adjustments to the dosing rate can be made by the operators based on measured filter effluent turbidity. 333
Section 13, Item J.
?
Influent Screening
and Mechanical
Flocculation
Sand Filtration
Chlorine Contact Basins
Backwash Solids
Drying and Storage
Effluent Pump Station
Clarifier
to Golf Course
Castle Oaks Golf Course
Prepared by: Prepared for:

Figure 2
WEST YOST - \\wya.local\Corporate\Clients\988 City of Ione\50-24-10 As Needed\GIS\MXD\COWRF Facilities.mxd - aguillebeau - 11/20/2024 0 100 200
Feet
City of Ione
Capacity and Operations TM
COWRF Facilities
? Control Valve
Pump Station
to Golf Course
COWRF Influent
Discharge to WWTP
Discharge to WWTP Ponds
COWRF Boundary
334
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December 9, 2024

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N-C-988-50-24-10-WP-CAPACITY AND OPERATIONS TM
Filtration
After flocculation, recycled water flows from the flocculation chambers by gravity through the tertiary filters. The tertiary filtration system consists of continuous backwash, upflow, deep bed, and granular media DynaSand filters manufactured by Parkson Corporation. There are four filter cells, each containing two 50 square feet (ft2) filter modules. The filter cells are operated in parallel with three duty and one standby unit. The design filtration rate for each filter cell is 2.8 gallons per minute per square foot (gpm/ft2); however, each filter unit should be able to process up to 5 gpm/ ft2.

The Parkson Dyansand filter is approved for the production of disinfected tertiary recycled water, as documented in a letter dated December 1, 1986, from the CDPH Drinking Water Program (now known as DDW)1. Additional design criteria for the tertiary filtration system is summarized in Attachment A.

Compressed air is used for continuous backwashing of a portion of the sand medium. Backwash (filter reject) from the filters is collected in a common trough and flows by gravity to the filter backwash clarifier. The filter reject stream is expected to be 5 to 10 percent of the total plant flow2. However, the filter reject flows are measured, and this data indicates that backwash flows are 10 to 20 percent of the total plant flow.

Chlorine Disinfection
After filtration, recycled water flows to the chlorine mixing chamber where the sodium hypochlorite solution is added. The sodium hypochlorite solution dosing pumps are flow paced to the plant influent flow meter to achieve a desired dosing rate. Adjustments to the dosing rate can be made by the operators based on measured final effluent chlorine residual. A high-speed mechanical mixer in the chlorine mixing chamber ensures that the chlorine solution is well mixed with the recycled water flow.

After mixing, recycled water enters the Chlorine Contact Basin (CCB), which is a concrete basin with a serpentine, rectangular shape (Figure 3). The CCB is divided into two halves (CCB-1 and CCB-2) which could be operated individually in parallel or together in series. However, the two basins are exclusively operated in series. Each half can also be isolated and operated independently when the other needs to be drained for maintenance. However, CCB maintenance is typically done when the COWRF is offline.

The total volume of the CCB is reported as a nominal 100,000 gallons3. The channels are 6 feet wide and 6 feet deep and are separated by 8-foot-high concrete baffle walls. However, the detailed record drawings for the COWRF4show that the CCB operating volume is approximately 112,000 gallons, with a length-to-width ratio of 66 to 1. At the COWRF’s design flow of 1.2 million gallons per day (MGD), the CCB’s hydraulic retention (HRT) time is 134 minutes. The HRT in the CCB is controlled solely by the influent flow rate. The fixed volume of water in the CCB is controlled by a slide gate in each CCB half that allows water to overflow into the effluent clear well. If only one half of the CCB is operated (CCB-1 or CCB-2), themaximum flow that can be treated is 0.6 MGD.

A tracer study will be conducted to demonstrate modal contact time for flow through CCB for compliance with CCR, Title 22, Section 60301.230.a.1. The tracer study protocol was submitted to the State Water Resources Control Board (SWRCB), Division of Drinking Water (DDW) for review on October 1, 2024. The tracer study will be conducted in winter 2024/2025, the results of which will be incorporated into an updated Title 22 Engineering Report.
1 CA SWRCB Division of Drinking Water. April 2023. Alternative Treatment Technology Report for Recycled Water, Appendix C.

Historic Conditionally Accepted Granular Media Filters. 2 City of Ione. May 1994. Castle Oaks Operation & Maintenance Manual. 3 City of Ione. May 1994. Castle Oaks Operation & Maintenance Manual. 4 Nolte and Associates. March 1992. City of Ione, Castle Oaks Wastewater Reclamation Plant, Record Drawings. 335 Section 13, Item J.

SLIDE GATE G-05-05 (OPEN) CL2 RESIDUAL ANALYZER FOR CT COMPLIANCE SLIDE GATE G-05-04 (CLOSED) SLUICE GATE G-05-01 (CLOSED) SLIDE GATE G-05-03 (OPEN) FILTER EFFLUENT CHLORINE MIXER, M-05-01.INJECT TRACER AT CHLORINE MIXING CHAMBER SLUICE GATE G-05-02 (OPEN) EFFLUENT PUMPS TO PLANT DRAIN SYSTEM W:\Clients\988 City of Ione\50-23-05 Title 22 Update\CAD\Figures\98850-2305-Fig3 Chlor-Contact-Basin Flow Schematic.dwg 11/21/2024 7:41 AMsbarber City of Ione COWRF Chlorine Contact Basin Flow Schematic Figure 3 Capacity and Operations TM336 Section 13, Item J.

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December 9, 2024

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Effluent Pumping
Downstream of the CCB effluent weir, the disinfected recycled water enters the effluent pump station wet well. There are two effluent pumps, each rated at 850 gpm. Therefore, each pump can convey the entire treatment flow of 1.2 mgd to the golf course.

The effluent flow meter that was originally installed at the COWRF was not capable of providing an accurate flow measurement in its configuration. Therefore, the City historically reported effluent flow as influent flow. With the adoption of the current Monitoring and Reporting Program in October 2021, the City began reporting the effluent flow as the difference between the influent flow and the measured filter backwash flow at the start of the 2022 irrigation season. The City recently replaced the effluent flow meter and will initiate using this flow meter to report effluent flow in the 2025 irrigation season.

Solids Treatment and Handling
The filter backwash stream is routed to the Filter Backwash Clarifier, where suspended solids are removed in the through settling. The solids concentration of the filter reject stream is estimated to be 400 to 600 mg/L and the maximum alum sludge loading from the filter is projected at 300 to 1,000 lb/day.

Overflow from the Filter Backwash Clarifier is discharged to the plant drain system that leads to the Decant Pump Station. The pump station discharges the backwash flow to the City of Ione WWTF collections system, where it is combined with raw wastewater and directed to the WWTF for treatment.

Sludge from the Filter Backwash Clarifier is pumped to one of the three sludge drying beds. After drying, the sludge is stored and eventually disposed of in a landfill. An under-drain on Sludge Drying Beds 1 and 2 returns decanted water by gravity to the Decant Pump Station. Sludge Drying Bed 3, constructed in 2002, is provided with an integral sump to return decant water to the Filter Backwash Clarifier.

RECYCLED WATER TREATMENT OPERATIONS
Secondary effluent is stored prior to discharge to the COWRF. As such, the influent flow does not follow a diurnal pattern. Instead, flow through the plant is steady throughout the day. As previously noted, the influent control valve is used to set the desired influent flow rate to the COWRF based on the demands of the golf course.

The COWRF is in operation when there is irrigation demand at the golf course, typically April through November. Recent flow rates at the COWRF from available Daily Monitoring Report (DMR) data from January 2018 through October 20235 are summarized on Figure 4. As previously noted, influent flow was reported as effluent flow prior to April 2022 and starting in 2022 effluent flows have been calculated. The maximum daily influent flow to the COWRF was approximately 1.25 MGD in January 2018. For months where no influent or effluent flows are shown, the COWRF was offline. 5 DMR data for May 2023 at COWRF was not available. 337 Section 13, Item J.

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Figure 4. Recent COWRF Flows

0.0 0.2

0.4 0.6

0.8 1.0

1.2 1.4
3/6/2017 4/10/2018 5/15/2019 6/18/2020 7/23/2021 8/27/2022 10/1/2023 11/4/2024 Flow, MGD
COWRF Influent Flow COWRF Effluent Flow
338
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December 9, 2024

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N-C-988-50-24-10-WP-CAPACITY AND OPERATIONS TM
Monthly average effluent flows from COWRF are summarized in Table 2. In recent years the average monthly flow through the COWRF ranged from 0.43 MGD to 0.95 MGD.

Table 2. Monthly Average Effluent Flows from COWRF
Month Effluent Flow(a,b), MGD
January -
February -
March -
April 0.53
May 0.63
June 0.82
July 0.95
August 0.92
September 0.68
October 0.48
November 0.43
December -
a) Data from available DMR data averaged over period between January 2018 and October 2023. The sole flow meter is located at the influent pump station. Prior to April 2022, influent flow was reported as effluent flow. Starting in 2022, effluent flows have been estimated. b) For months where a dash (-) is shown, plant was offline, therefore there was no effluent flow.

MGD = Million Gallons per Day

TREATMENT CAPACITY
The COWRF is designed to treat an average peak flow of 1.2 MGD. The facility’s treatment capacity is primarily limited by the CCB capacity.

REFERENCES
California State Water Resources Control Board, Division of Drinking Water. April 2023. Alternative Treatment Technology Report for Recycled Water, Appendix C. Historic Conditionally Accepted Granular Media Filters.

City of Ione. May 1994. Castle Oaks Operation & Maintenance Manual.

Nolte and Associates. March 1992. City of Ione, Castle Oaks Wastewater Reclamation Plant, Record Drawings. 339
Section 13, Item J.

As-Built Drawing Set Excerpts
Attachment A
340
Section 13, Item J.
341
Section 13, Item J.
342
Section 13, Item J.
www.hydroscience.com

ATTACHMENT E
Amador Regional Sanitation Agency
2024 Individual Water Balance Update
2024 COGC Recycled Water Demands TM
by West Yost Engineers
343
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1001 Galaxy Way
Suite 310
Concord CA 94520
925.949.5800 phone
925.949.5845 fax
westyost.com

TECHNICAL MEMORANDUM
DATE: December 10, 2024 Project No.: 988-50-24-10
SENT VIA: EMAIL
TO: George Lee, City of Ione
CC: Daniel Griffin, Castle Oaks Golf Course
Justin Granados, WaterStone Service
FROM: Allie Ahern, EIT
REVIEWED BY: Kathryn Gies, PE, RCE #65022
SUBJECT: Castle Oaks Golf Course Recycled Water Demands This technical memorandum (TM) provides information and supporting documentation related to water needs of the Castle Oaks Golf Course (golf course), which receives recycled water from the Castle Oaks Water Reclamation Facility (COWRF). The purpose of this TM is to inform development of a water balance for the Amador Regional Sanitation Authority (ARSA) wastewater disposal system. The following topics are addressed:
• Background Information
• Golf Course Irrigable Acreage
• Golf Course Storage Ponds
• Golf Course Agronomic Water Demands
• COWRF Influent Flows
• Golf Course Tailwater and Overspray Control and Monitoring

BACKGROUND INFORMATION
This section provides background information relevant to this TM. The following topics are addressed:
• Regulatory History
• Applicable Regulatory Standards for Water Balances
• Golf Course Demands vs. COWRF Influent Flows
347
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December 10, 2024

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N-C-988-50-24-10 AS NEEDED-WP
Regulatory History
The City of Ione (City), ARSA and Portlock International Ltd. (Portlock) are the three entities permitted the Central Valley Water Quality Control Board (Regional Board) under Water Reclamation Requirement Order 93-240 (WRRs) to land apply recycled water from the COWRF to the golf course. The City owns and operates the COWRF, which provides the recycled water to the golf course. The City also owns the golf course, which is leased and operated by Portlock. ARSA is permitted to supply water to the COWRF to meet the irrigation needs of the golf course.

The acreage and agronomic rate at which recycled water can be applied to the Castle Oaks Golf Course without violating setback requirements, Title 22 requirements, impacting groundwater, or causing runoff to surface water. These numbers and calculations should be provided and certified by Ione and Portlock International LTD. Supporting documentation and references must be included in the submittal. Information regarding tailwater control/return and monitoring plans for compliance with applicable land application area requirements must also be included.

Applicable Regulatory Standards for Water Balances
The 13267 Order states that the water balance must be in compliance with the requirements and guidance of the Regional Board’s guidance document Requirements for Water Balance Update and Calibration, which is provided as Attachment A to the 13267 Order. Several of the procedures defined in this guidance document are applicable to the development of this TM, as follows:

Requirements for Water Balance Update and Calibration, Section 4:

The normal operations and maintenance of land application areas should be considered. [Operations and Maintenance] O&M Manuals should be referenced as well as historical monitoring data (i.e. percolation rates, observed standing water). Specific conditions of the [WRRs] should also be taken into account. The following should be taken into consideration:

A. Recycling area/land application area/disposal system hydraulic loading rates should be distributed monthly in accordance with expected seasonal variations based on crop evapotranspiration rates.

B. The distribution of precipitation (i.e. storm intensity, light rain over a lot of days or heavy rain over a few days), as well as other factors such as wind and saturated conditions must be taken into account when determining the number of days a disposal system can be operated each month. The most reliable way to estimate this is based off of historical records from a water year of intensity similar to that which is being modeled.

C. It should be specified whether the tailwater is collected, and if so if it is returned to the sprayfields directly or to one of the ponds.

D.If applicable, storm water runoff shall be accounted for in the tailwater return calculations.

E. Maximum disposal capacity of land application areas should be based on soil studies, cropping plans, percolation studies, and/or operator notes. 348
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Requirements for Water Balance Update and Calibration, Section 5:

A. All water balances shall start on 1 October and end on 30 September. …
C. The water balance should include an assessment of the facility’s capacity and performance during a normal water year and during a year with a total annual precipitation for a return period of 100 years.

D. Local precipitation data for the 100-year annual return period, distributed monthly in accordance with mean monthly precipitation patterns shall be used. However, periods of high intensity storms should also be considered in the calculations.

E. All water balances should be based on all available data. All data should also be quality controlled and used with discretion.
…
G.For each wastewater treatment, storage, or disposal pond and containment structure, provide the following information:
a. Identification (name) and function of the pond.
b. Surface area, depth, and volumetric capacity at two feet of freeboard. c. Height (relative to surrounding grade), crest width, interior slope, and exterior slope of each berm or levee.
d. Materials used to construct each berm or levee.
e. Description of engineered liner, if any. Include a copy of the Construction Quality f. Estimated steady state percolation rate for each unlined pond. g. Depth to shallow groundwater below the base and pond inverts. h. Precipitation and evapotranspiration data shall be from recognized stations. The source of this information shall be provided, including a link to the data. i. Overfilling/overflow prevention features.
j. Operation and maintenance procedures.

Golf Course Demands vs. COWRF Influent Flows
During the COWRF tertiary treatment process, a fraction of the influent to the COWRF is discarded as filter backwash and sent to the City of Ione’s Wastewater Treatment Facility (WWTF). The remaining influent to the COWRF is treated to tertiary standards and recycled at the golf course. Therefore, the influent flow to the COWRF needs to be greater than the agronomic water demand of the golf course to accommodate the losses due to filter backwash, and the ARSA water balances need to include the portion of influent sent as filter backwash to the WWTF.

The City is concurrently in the process of preparing a water balance for its WWTF in accordance with a separate 13267 Order. The WWTF water balance will also need to account for the COWRF backwash flows.

Accordingly, this TM presents calculations that define both the COWRF influent flows needed to meet the golf course agronomic demands for use in the ARSA water balance and the backwash flow from the COWRF to the WWTF for use in the WWTF water balance.
349
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GOLF COURSE IRRIGABLE ACREAGE
The irrigable acreage of the golf course was determined based on inspection of the golf course irrigation system and discussions with staff. This area was mapped and quantified using GIS mapping and data processing tools. Figure 1 presents the map created. The following areas of the golf course were not included in the calculated irrigable acreage:
• natural, undeveloped areas surrounding Mule Creek and Sutter Creek • areas abutting residences surrounding the golf course; some of these areas are irrigated by residents while others remain unirrigated
• hardscape and permanent water features
The total irrigable area of the golf course was determined to be 130 acres. 350
Section 13, Item J.
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GOLF COURSE STORAGE PONDS
The golf course has nine ponds that can be filled with recycled water during the irrigation season. The ponds serve as aesthetic features and water hazard obstacles for the golf course and are used to hold recycled water before it is pumped to the golf course. Limited construction information is available for the ponds, but the ponds are understood to be unlined and constructed of native soil material. Estimates of the depth, volume and percolation rates of the ponds are not available. However, it is estimated that on average, the depth of groundwater below the golf course ranges from 8 to 13 feet. The surface area of each pond has been estimated using GIS mapping and data processing tools and is presented in Table 1.

Table 1. Golf Course Storage Pond Surface Area
Pond Name Surface Area, acres
Lake A 0.8
Lake B 1.2
Lake C 0.4
Lake D 1.1
Lake E 2.2
Lake F 1.1
Lake G 1.6
Lake H 1.4
Lake I 3.1
The ponds are hydraulically connected to each other. The maximum water level of each pond is controlled by a fixed standpipe located in an access port approximately 20 to 100 feet from the lake’s edge. Water overflowing the standpipe of the upstream lake is conveyed by to the following lake downstream, with Lake A being the furthest upstream lake, and Lake I being the furthest downstream lake. The Lake I overflow standpipe connects to a wetlands area that is tributary to the nearby surface water body Mule Creek. Figure 2 presents a schematic of the recycled water irrigation system.

Recycled water from the COWRF can be pumped directly to either Lake I or Lake A. Recycled water is then pumped from Lake I to the golf course irrigation system. Under current operations, recycled water is sent by default to Lake I. Golf course staff relate that recycled water is only pumped to Lake A for short periods during the irrigation season, when golf course demands are not keeping up with flows from the COWRF and Lake I is at risk of overflowing. Typically, recycled water that is directed to Lake A will remain in the Lake until it has percolated or evaporated. However, recycled water can discharge from Lake A to the downstream lakes if Lake A overflows. However, golf course staff indicate that the amount of recycled water flow sent to Lake A is not enough to result in overflows. 352
Section 13, Item J.

LEGEND
LAKES
B – H
City of Ione
Castle Oaks Golf Course
Project No.: 988-50-24-10 Recycled Water Demands
LAKE I

CASTLE OAKS
WATER

RECLAMATION

FACILITY
LAKE A

IRRIGATION

PUMP STATION

TO GOLF COURSE

PUTTING

GREEN &

DRIVING
RANGE

RECYCLED WATER

STORM/RECYCLED WATER

OVERFLOW TO

MULE CREEK

STORM WATER ONLY
Figure 2. Castle Oaks Golf Course Recycled Water
Storage and Irrigation System Schematic
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The ponds also serve as catchment for stormwater runoff the golf course. During the winter rainfall season, stormwater runoff will fill the nine ponds, and they will eventually overflow to Mule Creek. To prevent the discharge of recycled water to Mule Creek, recycled water is only delivered to the golf course during the irrigation season (typically between April and October). This allows for water in Lake I to percolate and evaporate before the rainy season begins. In addition, the recycled water remaining in Lake I at the end of the irrigation season is diluted with 1.2 million gallons of potable water. Golf course staff reported that this practice was developed in partnership with the California Department of Health Services1 to minimize the potential for discharge of recycled water to surface waters.

GOLF COURSE AGRONOMIC WATER DEMANDS
Calculation Procedures
The steps and major assumptions used to determine the rate at which recycled water can be supplied to the golf course are described below.

Climate Data
Rainfall data reported by the Ione National Climate Data Center (NCDC) weather station #0442832 was used to define the average annual rainfall, 1-in-100-year annual rainfall, and the monthly distributions of rainfall, as follows:
• The average rainfall year was defined as having a total rainfall of 22.0 inches. • The 1-in-100 rainfall year was defined as having a total rainfall of 41.1 inches. • The monthly distributions were defined based on the 1906 to 1977 monthly Normal rainfall distribution values, with the Normal values being statistically determined values reported by the California Department of Water Resources (DWR).

DWR defined all of these values. This information on is documented in Attachment A and summarized in Table 2.

Reference evapotranspiration (ET) for each month is based on long-term monthly average ET values for the Plymouth California Irrigation Management Information System (CIMIS) Station #227, located approximately 13 miles northeast of the golf course. This information is documented in Attachment A of this TM and summarized in Table 2, along with the monthly total rainfall values for the average and 1-in-100 rainfall years.
1 CDPH has since been incororpated into the State Water Board as the Division of Drinking Water (DDW). 354
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Table 2. Applicable Climate Data
Month Average Rainfall,
(a) inches 1-in-100 Year Rainfall,(a) inches Reference ET,(b) inches October 1.15 2.15 3.24
November 2.81 5.24 1.68
December 3.54 6.58 1.21
January 5.09 9.48 1.48
February 3.14 5.86 1.95
March 3.20 5.95 3.02
April 1.75 3.26 4.57
May 0.63 1.18 5.97
June 0.23 0.43 7.19
July 0.07 0.13 7.64
August 0.13 0.24 6.98
September 0.33 0.62 4.99
Total 22.1 41.1 49.9
(a) NCDC weather station #044283
(b) Plymouth CIMIS station #227
Crop ET
Monthly crop ET values for the golf course were calculated by multiplying the reference ET values from Table 2 by a representative crop coefficient. Grasses grown on the golf course include:
• perennial rye grass
• poa annua
• creeping bent grass
• tall fescue
• Bermuda grass
Apart from Bermuda grass, all grasses used on the golf course are considered cool season grasses. Meyer and Gibeault at the University of California, Irvine report monthly crop coefficients for cool season grasses (see of Attachment B). The average of these reported monthly crop coefficients for April to October, calculated to be 0.88, was used as a representative crop coefficient for all months.

Pond ET
Monthly ET values for the storage pond Lake I were set equal to the respective monthly reference ET values. 355
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Historical Recycled Water Demands
Evaluation of historical recycled water demands was based on the following:
• To properly maintain the golf course greens, recycled water is delivered to the COWRF and golf course solely based on golf course demands.
• Golf course flow data is tracked by golf course staff, and total monthly and annual flow volumes based on this data are shown in Table 3.
• The historical average volume of recycled water delivered was calculated for each calendar month and was used to calibrate and confirm the theoretical recycled water demand for the golf course.

Table 3. Historical Golf Course Recycled Water Demand
Month
Volume of Recycled Water Used, million gallons (MG) Average, 2017 2018 2019 2020 2021 2022 2023 2024 Average acre-feet October 16.5 8.4 16.7 14.5 8.2 9.1 11.9 20.3(a) 12.2 37.4 November 0 3.2 13.9 6.1 0 9.1 0 2.6(a) 5.3 16.4
December 0 0 0 0 0 0 0 0 0 0
January 0 0 0 0 0 0 0 0 0 0
February 0 0 0 0 0 0 0 0 0 0
March 0 0 0 0 0 0 0 0 0 0
April 0 0 0 1.1 12.7 8.1 0.9 0 2.9 8.8
May 18.1 19.1 15.1 14.1 25.2 12.1(b) 15.8 17.6 17.9 54.9 June 25.6 26.5 21.1 19.6 21.4 10.8(b) 22.0 28.3 23.5 72.2 July 29.4 29.0 27.2 26.6 31.7 20.4 25.1 28.3 27.2 83.6
August 29.1 29.8 26.5 25.8 23.3 21.0 22.0 26.1 25.5 78.1 September 23.0 24.1 24.1 16.2 9.0(c) 15.7 15.0 24.2 20.3 62.4 Total, MG 141.7 140.2 144.6 123.9 131.5 106.3 118.1 147.5 134.8 413.8 (a) Values excluded from average calculation. The COWRF influent flow meter failed on October 9, 2024 and COWRF staff requested that water be sent to the COWRF at a steady rate of 800 gallons per minute until the end of the irrigation season in mid-November.

Therefore, during this period, there was less ability to match the effluent flows from the COWRF to golf course agronomic demands and it is not clear these are representative values.
(b) Values excluded from average calculation. There was limited recycled water supply available from ARSA during the period of May to June 2022 and the golf course was under-irrigated.
(b) Value is excluded from average because it is anomalous when compared with September recycled water use volumes of other years.

Operations staff responsible for this data are not available to confirm its accuracy.

Theoretical Recycled Water Demands
Theoretical recycled water demands for the golf course were developed based on the following:
• Theoretical agronomic demands are calculated by multiplying the difference between the calculated monthly crop ET and monthly rainfall values by the total area of the golf course (130 acres) and dividing by an irrigation efficiency factor. For months with more precipitation than ET, the irrigation demand was set equal to zero.
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• Irrigation efficiencies for solid set spray irrigation systems like that used on the golf course can range from 60 to 85 percent (see Attachment C, Table 8.2b). A calibration process, described in the next section, has been used to define the irrigation efficiency for this site. • Theoretical evaporative losses from the storage ponds are calculated by multiplying the difference between the reference ET and monthly rainfall values by the total area of the impoundment. • As noted previously, recycled water is only sent to and pumped from Lake I. Therefore, evaporative losses from only Lake I (3.1 acres) are included. • Losses are calculated for months only when recycled water is delivered to the golf course. • There have been no attempts to quantify percolation losses from Lake I. Therefore, percolation losses are assumed to be zero.
• Total theoretical recycled water demands are the sum of the theoretical monthly golf course agronomic demands and the theoretical monthly evaporative losses from Lake I.

Average Year Theoretical Recycled Water Demand Calibration The site-specific irrigation efficiency factor used to calculate the theoretical irrigation demand is determined by adjusting the irrigation efficiency value used in the calculation of the average-year theoretical recycled water demand until the demand matches the historical recycled water supplied.

The resulting irrigation efficiency is 84 percent, on the upper end of the typical range for spray irrigation cited above. This calibration process demonstrates that the golf course irrigation system is very efficient and experiences limited losses.
1-in-100 Year Recycled Water Demand
The 100-year theoretical recycled water demand is calculated using the procedures described above but applying 1-in-100-year rainfall values and retaining the 84 percent irrigation efficiency determined from the average year water balance.

Agronomic Water Demands
The calculated average rainfall year theoretical demand to be used in the water balance analysis is shown in Table 4. The calculated average 1-in-100-year theoretical demand to be used in the water balance analysis is shown in Table 5.

The historical data show irrigation demands in November, but the theoretical demands do not indicate a need for irrigation water in this month. This discrepancy likely reflects the fact that rainfall typically does not begin until late November in this area, while there are still irrigation demands earlier in the month.

Despite this discrepancy, the annual theorical demand matches closely to the historical values for the average year. Therefore, the methodology applied provides an accurate estimate for purposes of developing an annual water balance for COWRF.
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Table 4. Monthly Golf Course Recycled Water Demand for an Average Rainfall Year Month
(1) (2) (3) (4) (5) (6)
Climate Values, inches Historical
Demand,
acre-feet
Theoretical Average-Year Demand, acre-feet
Rainfall
Reference
ET
Irrigation
Demand
Pond
Losses
Total
Demand
October 1.15 3.24 37.4 21.9 0.5 22.4
November 2.81 1.68 16.4 0 0 0
December 3.54 1.21 0 0 0 0
January 5.09 1.48 0 0 0 0
February 3.14 1.95 0 0 0 0
March 3.20 3.02 0 0 0 0
April 1.75 4.57 8.8 29.3 0.7 30.0
May 0.63 5.97 54.9 59.6 1.4 61.0
June 0.23 7.19 72.2 78.6 1.8 80.4
July 0.07 7.64 83.6 85.8 2.0 87.8
August 0.13 6.98 78.1 77.5 1.8 79.3
September 0.33 4.99 62.4 52.4 1.2 53.6
Total, acre-feet
per year (AFY) 22.0 49.9 413.8 405.1 9.4 414.5
Notes:
(1) 1906-1977 monthly rainfall normals for Ione NCDC weather station #044283 (2) Long-term monthly average reference ET from Plymouth CIMIS station #227 (3) Average of monthly irrigation volumes applied to the golf course from 2017 to 2024 from Table 3 (4) = (irrigated area of 130 acres) x [Column 2 x (crop coefficient of 0.88) - Column 1] / (irrigation efficiency of 0.84) / 12 inches/foot (5) = (storage pond area of 3.1 acres) x (Column 2 - Column 1) / 12 inches per foot (6) = Column 4 + Column 5
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Table 5. Monthly Golf Course Recycled Water Demand for a 1-in-100 Rainfall Year Month
(1) (2) (3) (4) (5)
Climate Values, inches Theoretical 100-Year Demand, acre-feet Rainfall Reference ET Irrigation Demand Pond Losses Total Demand October 2.15 3.24 9.0 0.3 9.3
November 5.24 1.68 0 0 0
December 6.58 1.21 0 0 0
January 9.48 1.48 0 0 0
February 5.86 1.95 0 0 0
March 5.95 3.02 0 0 0
April 3.26 4.57 9.8 0.3 10.1
May 1.18 5.97 52.5 1.2 53.7
June 0.43 7.19 76.1 1.7 77.8
July 0.13 7.64 85.0 1.9 86.9
August 0.24 6.98 76.1 1.7 77.8
September 0.62 4.99 48.6 1.1 49.7
Total, AFY 41.1 49.9 357.1 8.2 365.3
Notes:
(1) = 100-year return period annual total distributed monthly in proportion to 1906-1997 monthly Normals for Ione NCDC weather station #044283
(2) Long-term monthly average reference ET from Plymouth CIMIS station #227 (3) = (irrigated area of 130 acres) x [Column 2 x (crop coefficient of 0.88) - Column 1] / (irrigation efficiency of 0.84) / 12 inches per foot (4) = (storage pond area of 3.1 acres) x (Column 2 - Column 1) / 12 inches/foot (5) = Column 4 + Column 5
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COWRF INFLUENT FLOWS
Calculation Procedures
The theoretical influent flow to the COWRF is calculated for each month using the following formula:

Golf Course Irrigation Demand/(1-backwash percentage)
The Golf Course Irrigation Demands were discussed in the previous section. The backwash percentages are calculated based on historical COWRF influent and backwash flow data, as described in the sections below.

Historical COWRF Influent Flows
Historical monthly influent flows to the COWRF are shown in Table 6. Influent flows beginning in April 2022 are reported in the monthly COWRF discharge monitoring reports (DMRs). Prior to 2022, COWRF DMRs did not present influent flows. However, the influent flows were determined from available golf course demand data and backwash flow data.2
Table 6. Historical COWRF Influent Flows
Month
Volume of COWRF Influent Flow, MG
2017 2018 2019 2020 2021 2022 2023 2024 Average
October 19.5 10.3 20.7 17.9 10.5 10.9 19.2 27.7(a) 17.1 November 0 4.8 15.8 7.8 0 11.3 9.3 4.0(a) 8.8
December 0 0 0 0 0 0 0 0 0
January 0 0 0 0 0 0 0 0 0
February 0 0 0 0 0 0 0 0 0
March 0 0 0 0 0 2.0 0 0 2.0
April 0 0 0 0.9 14.4 12.7 2.1 0 7.5
May 20.4 21.6 17.1 16.8 29.1 14.0(b) 18.8 19.8 19.7
June 29.1 30.1 23.7 23.0 24.7 13.1(b) 25.8 32.0 25.2
July 34.1 33.5 31.2 30.2 35.7 23.1 29.5 32.1 31.2
August 33.3 36.9 33.3 30.1 27.0 23.2 27.4 32.3 30.3
September 27.1 27.7 28.1 20.2 11.2(b) 18.5 21.4 28.0 22.8 Total, MG 163.4 164.9 169.7 146.7 152.7 128.8 153.5 174.7 164.5 (a) Values excluded from this evaluation. The COWRF influent flow meter failed on October 9, 2024. Reported influent is an estimate of the actual flow received during this period.
(b) Although values reported in these months are not representative of typical influent flows (and thus irrigation demands), they are useful in determining the percentage of backwash flow generated. Therefore, these values are not excluded from this portion of the analysis. 2 To determine influent flows prior to April 2022, monthly COWRF effluent flows from the DMRs were compared to golf course flows and filter backwash flows. If the reported COWRF effluent flow was larger than the golf course flow, it was confirmed to be actual influent flow by verifying that it was equal to the sum of the golf course influent flow and the filter backwash flow. If the reported COWRF effluent flow was equivalent to the golf course flow, the COWRF influent flow was calculated by summing the COWRF effluent flow and filter backwash flow. The 2017 COWRF influent flows were calculated by summing monthly golf course influent flows and filter backwash flows because COWRF DMRs were not available. 360
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Historical COWRF Backwash Flows
Historical monthly filter backwash flows from the COWRF are shown in Table 7 .

Table 7. Historical COWRF Filter Backwash Flows
Month
Volume of COWRF Filter Backwash Flow, MG
2017 2018 2019 2020 2021 2022 2023 2024 Average
October 3.0 1.9 4.0 3.4 2.4 1.7 7.3(a) 5.0 3.1
November 0 1.1 1.9 1.7 0 2.3 4.1(a) 1.7 1.2
December 0 0 0 0 0 0 0 0 0.0
January 0 0 0 0 0 0 0 0 0.0
February 0 0 0 0 0 0 0 0 0.0
March 0 0 0 0 0 0 0 0 0.0
April 0 0 0 0 2.0 2.0 0.1 0 1.4
May 2.2 2.5 1.9 2.7 3.9 1.9 3.0 2.2 2.5
June 3.4 3.6 2.5 3.8 3.4 2.0 3.7 3.6 3.2
July 4.7 4.4 3.9 3.6 4.0 2.7 4.4 3.8 3.9
August 4.2 3.9 3.9 4.3 3.8 2.7 5.4(a) 5.1 4.0
September 4.1 3.5 4.0 4.0 2.6 2.2 6.4
(a) 5.5 3.7
Total, MG 21.7 20.9 22.1 23.4 21.9 17.5 34.4 26.8 23.5
(a) Values were not used in calculated average. Operations staff were performing excessive backwashing of the filters. This practice has since ceased.

Filter Backwash Flow Percentages
The percentage of COWRF influent flow that was discarded as backwash flow to the WWTF each month was calculated by dividing the backwash flow by the influent flow. Table 8 shows the results of this calculation. From the percentages shown, a monthly average was calculated. Monthly average backwash percentages range from 13 to 20 percent.
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Table 8. Historical COWRF Filter Backwash Flow Percentage Month
Filter Backwash Flow as a Percentage of Influent Flow, percent 2017 2018 2019 2020 2021 2022 2023 2024 Average
October 15 18 19 19 23 16 38
(a) 18(b) 18
November -
(c) 23 12 22 - 20 44(a) 41(b) 19
December - - - - - - - - -
January - - - - - - - - -
February - - - - - - - - -
March - - - - - - - - -
April - - - - 14 16 7
(d)
- 15
May 11 12 11 16 13 13 16 11 13
June 12 12 11 16 14 15 15 11 13
July 14 13 13 12 11 12 15 12 13
August 13 11 12 14 14 12 20(a) 16 13
September 15 13 14 20 23 12 30(a) 20 17
(a) Values were not used in calculated average. Operations staff were performing excessive backwashing of the filters. This practice has since ceased.
(b) Values excluded from this evaluation. The COWRF influent flow meter failed on October 9, 2024. Reported influent is an estimate of the actual flow received during this period. (c) “-“ indicate there were no flows to the COWRF during this period. (d) The backwash percentage during April 2023 was abnormally low. Influent flow to the COWRF began six days before the end of the month and effluent and backwash were only discharged on two of the six days. This value was not used in the calculated average.
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Theoretical COWRF Influent Flow
The calculated average rainfall year theoretical flow to the COWRF to be used in the water balance analysis is shown in Table 9. The calculated average 1-in-100-year theoretical flow to the COWRF to be used in the water balance analysis is shown in Table 10.

Table 9. Monthly COWRF Influent Demand for an Average Rainfall Year Month
Average-Year Golf Course
Recycled Water Demand,
(a)
acre-feet
COWRF Backwash Flow as a
Percentage of Influent Flow,
(b)
percent
Average-Year
COWRF Influent Flow,
(c)
acre-feet
October 22.4 18 27.3
November 0 19 0
December 0 - 0
January 0 - 0
February 0 - 0
March 0 - 0
April 30.0 15 35.3
May 61.0 13 70.1
June 80.4 13 92.4
July 87.8 13 100.9
August 79.3 13 91.1
September 53.6 17 64.6
Total, AFY 414.5 - 481.7
(a) From Table 4, Column 6
(b) From Average column in Table 8
(c) = Column 1/(1 - Column 2)
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Table 10. Monthly COWRF Influent Capacity for a 1-in-100 Rainfall Year Month
1-in-100-Year Golf Course
Recycled Water Demand,
(a)
acre-feet
COWRF Backwash Flow as a
Percentage of Influent Flow,
(b)
percent
1-in-100-Year
COWRF Influent Flow,
(c)
acre-feet
October 9.3 18 11.3
November 0 19 0
December 0 - 0
January 0 - 0
February 0 - 0
March 0 - 0
April 10.1 15 11.9
May 53.7 13 61.7
June 77.8 13 89.4
July 86.9 13 99.9
August 77.8 13 89.4
September 49.7 17 59.9
Total, AFY 365.3 - 423.5
(a) From Table 5, Column 5
(b) From Average column in Table 8
(c) = Column 1 / (1 - Column 2)
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Theoretical COWRF Backwash Percentages and Flows
A calculated theoretical backwash flow from the COWRF to the WWTF will be used in the water balance analysis for the WWTF, based on the influent flows from Table 9 and Table 10 and average historical backwash flow percentages by month from Table 8. The theoretical COWRF backwash flow for an average rainfall year is shown in Table 11. The theoretical COWRF backwash flow for a 1-in-100 rainfall year is shown in Table 12.

Table 11. Monthly COWRF Backwash Flow for an Average Rainfall Year Month
Average-Year
COWRF Influent Flow,
(a)
acre-feet
COWRF Backwash Flow as a
Percentage of Influent Flow,
(b)
percent
Average-Year
COWRF Backwash to WWTF,
(c)
acre-feet
October 27.3 18 4.9
November 0 19 0
December 0 - 0
January 0 - 0
February 0 - 0
March 0 - 0
April 35.3 15 5.3
May 70.1 13 9.1
June 92.4 13 12.0
July 100.9 13 13.1
August 91.1 13 11.8
September 64.6 17 11.0
Total, AFY 481.7 - 67.2
(a) From Table 9
(b) From Table 8
(c) = Column 1 x Column 2
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Table 12. Monthly COWRF Backwash Flow for a 1-in-100 Rainfall Year Month
1-in-100-Year
COWRF Influent Flow,
(a)
acre-feet
COWRF Backwash Flow as a
Percentage of Influent Flow,
(b)
percent
1-in-100-Year
COWRF Backwash to WWTF,
(c)
acre-feet
October 11.3 18 2.0
November 0 19 0
December 0 - 0
January 0 - 0
February 0 - 0
March 0 - 0
April 11.9 15 1.8
May 61.7 13 8.0
June 89.4 13 11.6
July 99.9 13 13.0
August 89.4 13 11.6
September 59.9 17 10.2
Total, AFY 423.5 - 58.2
(a) From Table 10
(b) From Table 8
(c) = Column 1 x Column 2

GOLF COURSE TAILWATER AND OVERSPRAY CONTROL AND MONITORING This section provides information about Best Management Practices (BMPs) and monitoring for tailwater and overspray control from the golf course. The following topics are addressed:
• Golf Course Field Monitoring
• Golf Course Best Management Practices
• Golf Course Storage Pond Monitoring
Golf Course Field Monitoring
The City, in coordination with the golf course management, is required to perform daily, weekly, and monthly monitoring of the golf course when recycled water is being applied, as outlined in the WRR’s Monitoring and Reporting Program (MRP). These requirements are summarized in Table 13. In addition to the elements outlined below, the daily inspections must note any evidence of erosion, field saturation, runoff or the presence of nuisance conditions.

The MRP was adopted December 21, 2021, and did not become effective until after the end of the 2021 irrigation season. Since its adoption, the MRP requirements related to the golf course operations shown in Table 13 have not been satisfied. The City and golf course staff are currently developing the protocols to implement this monitoring and will initiate the program beginning in the 2025 irrigation season. 366
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Table 13. Golf Course Monitoring Requirements
Constituent Units Type of Sample Sampling Frequency Reporting Frequency Flow gallons Continuous
Daily Monthly
Rainfall(a) inches Measurement
Acreage Applied(b) acres Calculated
Tailwater Runoff Observation -- Observation
(a) As measured at the weather station nearest to the disposal site. (b) Specific disposal fields shall be identified.

Flow
Currently, golf course staff monitor the daily total flow that is applied to the golf course. This flow is measured from the irrigation pump station and recorded in the golf course’s central computer system.

The measurement can be reported in up to 15-minute increments. Golf course staff report the daily total flows to the City.

Rainfall
Rainfall collects in a plastic rain gage located at the maintenance yard, and golf course staff manually read the gage daily at approximately the same time of day. That measurement is compared to a reported weather station located in the nearby City of Jackson to confirm its accuracy. The onsite, measured rainfall data is reported to the City.

Acreage Applied
The golf course’s central computer system has the ability report the areas that are watered each night.

These areas are grouped and reported by area category according to the type of plant that is watered.

The area categories are:
• Greens
• Tees
• Fairway
• Perimeter
• Rough
• Club House
• Driving Range
• Putting Green
Irrigation generally occurs on all areas of the golf course simultaneously. In rare instances an area category may be watered alone. Starting with the 2025 irrigation season, golf course staff will report the acreage that is watered daily and include that information in the flow report provided to the City monthly. 367
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Tailwater Runoff Observation Monitoring
Starting with the 2025 irrigation season, City staff will inspect the golf course daily for evidence of runoff and overspray. These inspections will occur in the morning, just after irrigation occurs. During these inspections, special attention will be paid to the following five vulnerable areas, which have the most potential for recycled water to escape the use area:
• Castle Oaks Clubhouse
• Areas abutting Mule Creek
• Spyglass Drive near the Irrigation Pump Station
• Castle Oaks Drive and Shakeley Lane intersection
• Near the bathroom by Vista Lane
Monitoring each location will be done through an observatory drive by each location in the early morning.

Evidence of runoff or overspray includes wet areas on hardscape sidewalks and roadways surrounding the extents of the landscaped area. If these areas are wet or water appears to be draining from landscape into the gutters, the irrigation system should be further investigated for problems. Inspection logbook entries for the golf course monitoring will be submitted with the monthly monitoring reports.

Golf Course Best Management Practices
Overspray and runoff of recycled water from the use area is minimized and controlled through the implementation of BMPs. Spray irrigation systems are vulnerable to inefficiencies related to runoff or overspray caused by pressure fluctuations, wind, or equipment malfunction. If any part of the system is not working optimally, the result is a less uniform application of water which increases the likelihood of water escaping the recycled water use area. Even the most efficiently designed system must be maintained and constantly monitored to mitigate system avoid problems.

The COWRF BMP strategies include engineered controls and mechanisms to minimize runoff or overspray and practices to improve the application of water to a use area. Specific BMPs employed to control for runoff or overspray include:
• Irrigation is ceased during extended and extensive windy periods. • Irrigation is avoided when the soil is saturated to prevent runoff. • All sprinkler heads are uniform in brand, model and nozzle size to apply water as uniformly across the plant material as possible.
• A minimum four-foot distance from neighboring backyards and buildings is maintained as practical throughout areas of the golf course. This has been done through head removal, spray range or arc reduction or elimination of a zone. In areas where the four-foot buffer cannot be maintained and irrigated turf is desired, such as near a tee, hole or walkways, the irrigation water is applied with lower impact heads with a smaller arc radius. • Irrigation occurs in the evening or early morning hours to avoid public interaction, reduce evaporative loses, and take advantage of calmer wind patterns. • Good horticultural practices are performed including, mowing, de-thatching, aeration, and pest control as necessary to increase the plant and soil water absorbance. • Irrigation is applied as close as practical to match the amount of water lost through ET and the soil needs.
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• Duration of water application is applied to match percolation rates to reduce runoff. • Installation of low angle heads have been installed in areas near residential backyards to reduce mist from wind drift of spray.
• Tall plants are present along edges and perimeters to create a plant buffer. • Regular maintenance is performed of the irrigation system which includes inspecting and repairing leaks.

Golf Course Storage Pond Monitoring
Monitoring of irrigation storage ponds when they contain recycled water is also required under the MRP.

These requirements are summarized in Table 14.

Table 14. Golf Course Storage Pond Monitoring Requirements Constituent Units Type of Sample Sampling Frequency Reporting Frequency Freeboard feet Measurement Twice Weekly –
3 days apart
Monthly
Odors -- Observation Weekly
Dissolved Oxygen milligrams per
liter Grab Weekly
pH pH units Grab Monthly
Similar to the irrigation area, the MRP requirements related to the ponds have not been consistently satisfied. The City and golf course staff are currently developing the protocols to implement this monitoring and will initiate the program beginning in the 2025 irrigation season.

Freeboard
The MRP requires the freeboard be monitored as the difference between the top of the bank of the storage pond to the level of the water. This measurement provides the City with confidence that recycled water cannot escape the storage pond containment area. However, as noted previously, each pond is equipped with a standpipe that serves as an overflow structure. Therefore, it is more appropriate to monitor freeboard as the difference between the top of the overflow structure to the top of the water surface.

Currently, the City has the ability to measure the freeboard of Lake A by means of a level monitoring rod.

This capability is not set up in Lakes B through I. Lake I is manually kept at a level that is below the 12-inch overflow standpipe that conveys overflow water to a wetland area that eventually flows to Mule Creek.

Prior to the start of the 2025 irrigation season, the City will need to install a level monitoring rod in each pond so that freeboard can be measured.

In addition, the City will employ the following monitoring practices in the 2025 irrigation season:
• Twice a week during the irrigation season, each storage pond should be observed, and freeboard monitored.
• For Pond I, it is expected that there will be recycled water present in the pond throughout the irrigation season and this pond should be monitored during each bi-weekly event. 369
Section 13, Item J.

TM – City of Ione
December 10, 2024

Page 24 ends

N-C-988-50-24-10 AS NEEDED-WP
• Recycled water is occasionally directed to Pond A. Therefore, this pond will be inspected as part of the bi-weekly monitoring. If there is standing water present in Pond A, then monitoring of this pond will be completed.
• If there is any evidence that Pond A has overflowed to Pond B (or any downstream pond) via the pond standpipes, then monitoring of the downstream ponds will also be performed. • City staff will be responsible for making the appropriate observations to determine whether recycled water is being stored in any of the ponds.
• Golf course staff will provide information to the City regarding where COWRF flows are directed.

Specifically, the monthly reports provided to the City will include information about which pond was receiving flow on each day.

Odors
The City is required to evaluate if any objectionable odors are being emitted from the storage ponds once every week. This will be needed for each pond that holds recycled water.

Dissolved Oxygen and pH
The City is required to collect and measure the dissolved oxygen and pH in a grab sample collected from each recycled water storage pond weekly. These measurements can be made using field test instruments provided that:
• The operator is trained in proper use and maintenance of the instruments, • The instruments are field calibrated at the frequency recommended by the manufacturer, • The instruments are serviced and/or calibrated at the manufacturer’s recommended frequency, and • Field calibration reports are maintained and a calibration log verifying calibration of all handheld monitoring instruments and devices are submitted with the monthly monitoring report. 370
Section 13, Item J.

Rainfall and Reference ET Data
Attachment A
371
Section 13, Item J.

IONE, CALIFORNIA (044283)
Period of Record Monthly Climate Summary
Period of Record : 03/01/1906 to 06/30/1977
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Average Max.

Temperature (F) Insuff icient Data
Average Min.

Temperature (F) Insuff icient Data
Average Total
Precipitation (in.) 5.08 3.14 3.19 1.75 0.63 0.23 0.07 0.13 0.33 1.15 2.81 3.53 22.04 Average Total
SnowFall (in.) 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 Average Snow Depth
(in.) 0 0 0 0 0 0 0 0 0 0 0 0 0
Percent of possible observations for period of record.

Max. Temp.: 0% Min. Temp.: 0% Precipitation: 99.9% Snowfall: 99.9% Snow Depth: 99.8% Check Station Metadata or Metadata graphics for more detail about data completeness.

Western Regional Climate Center, [email protected]
10/10/24, 2:42 PM IONE, CALIFORNIA Period of Record Monthly Climate Summary https://wrcc.dri.edu/cgi-bin/cliRECtM.pl?ca4283 1/1
372
Section 13, Item J.

Rainfall Depth Duration Frequency at Ione
Station Number Station County Latitude Longitude Elevation Years Recorded B00 4283 00 Ione Amador 38.348 -120.938 284.0 89
Rainfall Statistics 1-Day 2-Day 3-Day 4-Day 5-Day 6-Day 8-Day 10-Day 15-Day 20-Day 30-Day 60-Day 1-Year Pr=0.5 1.92 2.55 3.01 3.38 3.70 3.99 4.48 4.91 5.79 6.51 7.68 10.19 21.28 Pr=0.2 2.55 3.37 3.98 4.47 4.89 5.27 5.92 6.48 7.64 8.58 10.11 13.39 27.84 Pr=0.1 2.92 3.87 4.55 5.11 5.60 6.02 6.76 7.40 8.71 9.78 11.52 15.23 31.54 Pr=0.04 3.36 4.44 5.22 5.86 6.40 6.89 7.73 8.45 9.94 11.16 13.13 17.32 35.70 Pr=0.02 3.66 4.83 5.67 6.36 6.96 7.48 8.39 9.17 10.78 12.09 14.22 18.74 38.51 Pr=0.01 3.94 5.19 6.10 6.84 7.47 8.04 9.01 9.84 11.57 12.97 15.23 20.06 41.11 Pr=0.005 4.21 5.54 6.51 7.29 7.96 8.56 9.59 10.48 12.31 13.79 16.19 21.31 43.57 Pr=0.002 4.54 5.97 7.01 7.85 8.58 9.22 10.33 11.28 13.23 14.82 17.40 22.87 46.64 Pr=0.001 4.79 6.29 7.38 8.26 9.02 9.69 10.85 11.85 13.90 15.57 18.26 23.99 48.84 Pr=0.0001 5.53 7.26 8.50 9.52 10.39 11.15 12.48 13.62 15.96 17.87 20.94 27.46 55.66 Annual Maxima 1-Day 2-Day 3-Day 4-Day 5-Day 6-Day 8-Day 10-Day 15-Day 20-Day 30-Day 60-Day 1-Year 2007 --- --- --- --- --- --- --- --- --- --- --- --- --- 2006 --- --- --- --- --- --- --- --- --- --- --- --- --- 2005 --- --- --- --- --- --- --- --- --- --- --- --- --- 2004 --- --- --- --- --- --- --- --- --- --- --- --- --- 2003 --- --- --- --- --- --- --- --- --- --- --- --- --- 2002 --- --- --- --- --- --- --- --- --- --- --- --- --- 2001 --- --- --- --- --- --- --- --- --- --- --- --- --- 2000 1.85 2.80 4.29 4.74 4.99 4.99 5.22 5.79 7.52 9.05 10.35 11.82 21.39 1999 2.02 2.44 3.42 3.42 3.42 3.42 3.42 4.17 5.51 5.72 8.41 10.90 15.39 1998 2.37 3.55 4.11 4.36 4.98 5.85 6.61 7.31 8.07 10.05 14.21 21.25 30.46 1997 2.37 3.55 4.11 4.36 4.98 5.85 6.61 7.31 8.07 10.05 14.21 21.25 43.59 1996 3.75 3.85 3.85 3.85 3.85 3.85 3.85 3.85 4.74 5.27 6.16 11.53 22.80 1995 2.90 4.71 5.05 5.33 5.58 5.71 7.45 8.02 9.08 9.83 12.42 16.90 35.50 1994 1.27 1.70 1.95 2.05 2.15 2.42 2.55 2.55 3.45 3.67 5.27 5.87 15.52 1993 1.81 2.26 2.26 2.84 3.18 4.50 4.91 5.13 7.10 7.52 10.16 16.58 29.21 1992 2.30 3.18 3.18 3.24 4.11 5.17 5.97 6.06 6.98 7.16 9.13 10.62 20.43 1991 1.60 2.28 2.88 3.52 3.52 3.52 4.08 5.15 6.28 7.38 10.07 11.94 16.59 1990 1.82 2.35 2.37 2.37 2.37 2.37 2.37 2.37 2.90 2.90 3.33 6.23 17.33 1989 1.05 1.90 2.05 2.06 2.26 2.41 2.52 2.82 3.36 3.75 5.85 7.67 16.85 1988 1.55 1.90 1.90 1.90 1.90 1.90 2.05 2.13 2.75 3.47 4.78 6.57 11.67 1987 1.81 2.43 2.54 2.54 2.87 2.87 3.38 3.62 3.62 5.31 5.31 9.80 13.86 1986 2.75 4.85 5.65 6.65 6.85 6.95 7.90 8.00 8.00 9.45 12.97 18.47 33.02 1985 --- --- --- --- --- --- --- --- --- --- --- --- 17.93 1984 --- --- --- --- --- --- --- --- --- --- --- --- 23.39 1983 --- --- --- --- --- --- --- --- --- --- --- --- 41.81 1982 --- --- --- 4.62 5.24 5.24 5.53 5.53 7.29 8.43 9.95 15.59 39.56 1981 2.04 2.94 3.80 4.17 4.32 5.01 6.02 6.02 6.21 6.21 6.62 11.24 17.15 1980 --- --- --- --- --- --- --- --- --- --- --- --- 26.42 D
10/10/24, 2:23 PM Rainfall Depth Duration Frequency
https://ferix.water.ca.gov/webapp/precipitation/frequenciesTable.jsp?id=1100428300&t=D&v=1&source=B195# 1/4 373
Section 13, Item J.
1979 1.54 2.28 2.83 3.82 3.82 3.82 4.02 4.97 5.49 6.53 7.09 12.65 20.87 1978 1.54 2.28 2.83 3.82 3.82 3.82 4.02 4.97 5.49 6.53 7.09 12.65 20.87 1977 0.92 1.03 1.09 1.12 1.12 1.12 1.24 1.26 1.26 1.26 2.18 3.32 8.73 1976 0.78 1.23 1.70 1.70 1.91 2.06 2.06 2.06 2.18 3.21 3.73 5.00 11.87 1975 1.97 2.56 3.14 3.27 3.38 3.52 4.84 6.08 7.82 8.47 8.50 15.06 28.24 1974 --- --- --- --- --- --- --- --- --- --- --- --- 33.80 1973 2.48 2.76 3.51 4.54 4.86 4.86 6.09 7.38 8.60 9.26 12.09 19.82 35.95 1972 3.05 3.88 3.92 3.98 3.98 5.03 5.90 5.96 6.05 6.73 7.92 9.62 16.80 1971 3.05 4.40 5.02 5.13 6.25 6.57 6.57 7.61 8.20 8.22 9.81 13.34 21.20 1970 2.94 2.94 3.48 3.48 3.72 3.72 4.97 5.90 6.37 7.01 9.55 12.27 21.13 1969 2.75 3.15 3.15 3.23 3.31 3.54 5.63 6.09 8.33 8.80 9.89 16.66 30.23 1968 1.76 2.12 2.12 2.43 2.43 2.48 2.51 3.20 3.20 3.49 4.61 8.77 17.12 1967 2.52 4.13 4.15 4.63 4.97 4.99 5.38 6.53 7.36 7.36 7.89 11.44 29.07 1966 1.79 1.95 2.46 2.48 3.27 3.74 4.03 4.13 5.17 5.17 5.17 9.69 16.47 1965 --- 3.43 --- --- --- --- --- 7.18 8.10 --- --- --- 25.01 1964 1.98 2.44 2.86 3.06 3.06 3.06 3.25 3.45 5.45 6.58 6.84 9.13 18.12 1963 2.88 3.52 4.20 4.65 4.65 4.65 4.65 4.65 6.07 6.38 6.38 10.35 24.44 1962 1.25 2.08 2.93 3.02 4.05 4.53 6.47 7.17 7.61 7.75 9.09 11.98 18.00 1961 1.38 1.68 2.16 2.16 2.16 2.26 2.40 2.77 2.93 3.23 4.81 6.51 13.82 1960 1.33 1.53 1.86 1.86 2.09 2.42 2.82 3.25 3.67 5.03 6.18 7.86 16.68 1959 1.65 2.09 2.09 2.55 2.88 3.22 3.68 4.01 4.01 4.75 6.13 10.54 13.45 1958 --- --- --- --- --- --- --- --- --- --- --- --- 41.69 1957 --- --- --- --- --- --- --- --- --- --- --- --- 18.93 1956 --- --- --- --- --- --- --- --- --- --- --- --- 28.58 1955 --- --- --- --- --- --- --- --- --- --- --- --- 18.28 1954 --- --- --- --- --- --- --- --- --- --- --- --- 16.40 1953 --- --- --- --- --- --- --- --- --- --- --- --- 15.10 1952 2.21 3.15 3.68 3.77 3.77 3.77 3.77 4.06 4.68 6.56 7.47 13.11 27.05 1951 4.65 5.30 5.30 5.30 5.55 5.70 6.24 6.25 6.25 8.87 10.85 14.60 28.76 1950 2.70 2.70 2.70 3.97 3.97 3.97 3.97 5.05 5.05 5.55 9.52 10.41 18.30 1949 1.76 2.71 3.14 3.14 3.14 3.14 3.72 3.86 4.87 5.45 6.93 10.49 17.23 1948 1.28 1.41 1.70 1.83 2.03 2.03 2.43 2.43 4.08 4.39 6.67 8.68 17.76 1947 2.16 3.12 3.20 3.20 3.91 3.91 3.91 4.13 4.13 4.13 4.82 7.33 14.54 1946 1.90 1.90 3.20 3.38 4.37 4.98 5.16 5.42 5.70 6.31 7.49 11.80 20.14 1945 2.68 3.88 4.78 4.78 4.98 5.27 5.27 5.27 5.66 5.66 5.66 9.58 23.66 1944 2.25 2.41 2.53 2.53 3.23 3.39 3.93 4.28 5.68 5.68 7.47 10.20 19.25 1943 2.05 2.78 3.58 3.81 4.43 4.77 5.38 5.42 7.10 8.03 10.13 15.90 27.61 1942 2.00 3.48 4.20 4.60 5.32 5.81 5.91 5.91 7.68 8.17 8.17 12.92 26.67 1941 1.85 2.40 2.46 3.46 5.46 5.46 4.17 4.52 7.17 8.59 11.13 14.00 25.17 1940 1.65 2.72 3.46 3.76 4.20 4.79 5.24 5.54 5.95 6.00 8.96 16.37 24.86 1939 1.72 2.40 2.55 2.80 2.80 2.80 2.80 2.80 2.80 3.17 3.42 5.93 14.01 1938 2.30 3.65 4.05 4.55 4.80 4.80 5.25 6.95 9.40 10.35 12.10 16.00 27.25 1937 4.40 4.65 5.85 6.15 6.60 6.95 7.70 8.15 8.70 9.50 10.10 19.90 34.99 1936 2.00 2.30 3.50 4.20 4.35 4.50 6.05 6.40 10.33 10.33 13.28 19.99 28.29 1935 2.50 2.72 2.72 2.72 3.25 4.30 4.52 4.52 5.22 5.65 6.35 9.47 23.94 1934 1.70 2.85 2.85 4.05 4.52 4.52 4.52 4.52 4.52 6.40 8.77 9.67 17.86 10/10/24, 2:23 PM Rainfall Depth Duration Frequency
https://ferix.water.ca.gov/webapp/precipitation/frequenciesTable.jsp?id=1100428300&t=D&v=1&source=B195# 2/4 374
Section 13, Item J.
1933 1.20 1.72 1.72 1.72 2.32 3.12 3.12 3.82 3.82 3.82 5.07 7.87 12.77 1932 1.75 1.92 2.59 3.58 3.75 3.80 4.49 4.97 5.58 5.88 6.60 10.05 19.99 1931 1.65 1.65 1.65 2.53 2.53 2.53 2.65 2.65 2.65 2.65 3.92 6.39 12.62 1930 1.39 2.25 2.25 2.57 2.57 2.78 3.35 3.71 5.17 5.33 5.62 10.86 17.07 1929 1.91 2.98 3.49 3.49 3.49 3.49 3.49 3.57 4.07 4.07 4.07 6.57 15.52 1928 1.68 2.60 3.40 4.06 4.79 4.92 4.92 4.92 5.92 6.10 6.27 9.09 18.80 1927 1.50 3.00 3.00 4.25 4.25 4.51 5.46 5.96 6.26 6.91 7.41 10.51 24.11 1926 2.55 2.80 2.90 3.55 3.55 4.55 5.10 5.10 6.48 8.99 10.04 10.29 21.54 1925 1.95 3.05 3.27 3.27 3.52 3.74 4.27 5.79 5.94 7.79 8.41 11.84 28.60 1924 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35 2.35 3.00 3.00 4.95 10.50 1923 2.20 3.00 4.30 5.30 5.30 5.30 5.50 6.10 6.70 6.70 9.30 14.15 26.07 1922 2.17 2.52 3.45 3.95 3.95 3.95 3.95 4.44 7.09 7.16 9.46 14.80 24.30 1921 3.85 3.95 4.50 4.72 4.72 4.72 4.72 5.72 6.62 7.02 7.72 13.51 26.57 1920 2.10 3.55 3.90 4.05 4.20 4.20 4.20 4.31 4.82 5.19 7.04 9.26 15.46 1919 2.25 3.55 3.90 4.00 4.05 4.40 4.60 4.70 5.00 6.45 8.15 10.35 18.75 1918 1.60 2.35 2.35 2.35 3.45 4.25 4.70 4.70 6.50 6.50 8.10 11.30 15.50 1917 1.30 2.30 2.60 2.90 3.25 3.55 4.10 4.35 4.55 4.55 5.35 7.25 17.70 1916 --- --- --- --- --- --- --- --- --- --- --- --- 20.00 1915 1.50 1.95 2.15 2.30 2.83 3.03 3.88 4.20 5.88 6.20 7.77 10.87 22.80 1914 2.26 3.11 3.49 3.61 3.99 3.99 3.99 4.48 5.47 6.96 9.81 13.52 22.90 1913 1.20 1.84 2.22 2.72 2.95 3.36 3.36 3.55 4.01 4.01 4.01 4.86 14.26 1912 0.69 1.04 1.15 1.22 1.30 1.45 1.86 2.16 2.47 2.86 3.43 5.36 12.68 1911 2.17 3.57 5.27 6.12 6.45 7.30 7.80 8.42 10.82 15.51 18.06 24.30 30.46 1910 2.00 3.00 3.00 3.45 3.88 3.88 3.93 3.93 4.00 4.69 5.92 8.90 20.89 1909 1.45 2.60 3.80 4.42 4.54 5.07 5.99 6.39 7.99 9.21 12.66 19.24 26.01 1908 1.30 1.60 1.60 1.78 1.78 1.78 1.83 3.03 3.63 3.63 5.51 9.04 14.27 1907 4.37 6.79 7.38 7.53 8.38 8.53 8.53 8.53 8.53 10.60 12.20 18.04 33.82 1906 2.40 2.54 3.22 3.62 3.85 3.85 3.85 5.03 7.47 9.20 10.45 15.43 30.93 1905 2.90 2.90 2.90 3.20 4.20 4.20 4.55 4.85 5.55 5.55 5.50 9.65 25.95 1904 1.51 2.62 3.12 3.15 3.15 3.25 3.75 4.86 6.07 6.42 7.20 12.05 21.42 1903 1.85 2.92 3.58 4.10 5.01 5.03 5.03 5.53 5.53 7.54 9.71 10.34 22.39 1902 1.21 1.79 2.09 2.61 3.01 3.41 3.87 4.41 5.03 6.03 7.72 9.29 20.19 1901 2.05 2.79 3.61 4.03 4.03 4.72 5.54 5.52 5.54 7.35 7.69 11.29 25.48 1900 1.85 2.34 2.41 2.80 2.86 2.86 2.86 3.88 4.82 5.66 6.45 9.69 21.51 1899 1.93 2.56 3.20 3.54 4.04 4.04 4.94 7.17 7.80 7.93 9.00 9.22 20.03 1898 3.60 4.47 4.64 4.64 4.64 4.64 4.64 4.76 5.11 5.11 5.23 7.30 13.77 1897 --- --- --- --- --- --- --- --- --- --- --- --- --- 1896 --- --- --- --- --- --- --- --- --- --- --- --- --- 1895 --- --- --- --- --- --- --- --- --- --- --- --- --- 1894 --- --- --- --- --- --- --- --- --- --- --- --- --- 1893 --- --- --- --- --- --- --- --- --- --- --- --- --- 1892 --- --- --- --- --- --- --- --- --- --- --- --- --- 1891 --- --- --- --- --- --- --- --- --- --- --- --- --- 1890 --- --- --- --- --- --- --- --- --- --- --- --- --- 1889 --- --- --- --- --- --- --- --- --- --- --- --- --- 1888 --- --- --- --- --- --- --- --- --- --- --- --- --- 10/10/24, 2:23 PM Rainfall Depth Duration Frequency
https://ferix.water.ca.gov/webapp/precipitation/frequenciesTable.jsp?id=1100428300&t=D&v=1&source=B195# 3/4 375
Section 13, Item J.

California Irrigation Management Information System (CIMIS) Rendered in ENGLISH Units.Printed on Wednesday, August 31, 2022Average ETo Values by StationMonthly Average ETo Report Stn Id Stn Name CIMIS Region Jan
(in)
Feb
(in)
Mar
(in)
Apr
(in)
May
(in)
Jun
(in)
Jul
(in)
Aug
(in)
Sep
(in)
Oct(in)
Nov
(in)
Dec
(in)
Total
(in)
227 Plymouth SFH 1.48 1.95 3.02 4.57 5.97 7.19 7.64 6.98 4.99 3.24 1.68 1.21 49.92 CIMIS Region Abbreviations
BIS - Bishop CCV - Central Coast Valleys ICV - Imperial/Coachella Valley LAB - Los Angeles Basin MBY - Monterey Bay NCV - North Coast Valleys NEP - Northeast Plateau SAV - Sacramento Valley SBE - San Bernardino SFB - San Francisco Bay SJV - San Joaquin Valley SFH - Sierra Foothill SCV - South Coast Valleys

Page 1 ends

Section 13, Item J.

Turfgrass Performance Under Reduced Irrigation
Meyer and Gibeault
Attachment B
377
Section 13, Item J.

Class A Weather Bureau evaporation pan
measured evapotranspiration from experimental turfgrass plots at the UC South Coast Field Station at Irvine.

Turfgrass performance
under reduced irrigation
Jewel1 L. Meyer 0 Victor A. Gibeault
Turf grass in California requires irrigation during all or most of the year. Water restrictions imposed during the drought in
1976 and 1977 forced turf managers to
reexamine many concepts about irrigation. Turfgrass managers had to make drastic cuts in water use and hope that the
turf would survive. One significant result
of the drought was the realization that
lower levels of turf quality were acceptable in many situations and that large water savings could be achieved. No information was available, however, on the best conservation practices or on the
minimum amounts of water needed to
keep the turf alive.

Research was begun in 1979 to produce irrigation methodology that could be used to develop water-saving irrigation
practices anywhere in California and in
other arid and semiarid regions. The
three-year study showed that major savings of water can be achieved, especially with warm-season grasses, with no appreciable loss of turf quality.

Turf-irrigation study
Specifically, the objectives of the research were to: (1) investigate the effects of applying reduced amounts of irrigation
water calculated as a percentage of evapotranspiration of applied water on coolseason and warm-season turfgrasses; (2) evaluate a below-ground system as a potentially more efficient method of turf irrigation than standard sprinkler application; and (3) develop a set of crop coefficients that California turfgrass
managers can use to determine on-site
water use by both cool- and warm-season
turfgrasses.

The study was conducted at the University of California South Coast Field Station, Irvine. The variables tested included: two irrigation methods, sprinkler application of water and a subterranean
or buried trickle/drip water application
(8-inch depth, 23-inch spacing); three irrigation regimes, 100,80, and 60 percent of calculated evapotranspiration; and six
commonly used turfgrasses, three coolseason varieties (Kentucky bluegrass, perennial ryegrass, and tall fescue) and three warm-season types (hybrid bermudagrass, zoysiagrass, and Seashore Paspalum).

The field plot was a randomized splitblock design. The area was divided into two turf blocks, one for cool-season
grasses and the other for warm-season
grasses. Each block consisted of four replications, and within each replication were six randomized irrigation plots measuring 15 by 24 feet. Irrigation plots were divided into three turf subplots of 8 by 15
feet. The three sprinkler and three subterranean irrigation plots per replication were installed in September 1979 for
above- and below-ground water application. Each sprinkler irrigation plot contained six high-pop brass sprinkler heads designed to apply 10 gallons of water per
minute at a pressure of 35 pounds per
square inch. The coefficient of uniformity
was 87 percent.

Tensiometers at 3- and 6-inch depths in
the cool-season grasses and 8- and 12-inch
depths in the warm-season grasses indicated soil water status; neutron probe access tubes were installed in plots to a depth of 4 feet in the cool-season and 6
feet in the warm-season grasses. Scheduling was by the water budget technique calculated weekly using wind-modified
pan evaporation data. State-of-the-art
controllers were programmed with this
irrigation scheduling information. The
amount of irrigation was modified so that
water did not pass below the +foot and 6-
foot depths of the neutron probe access
tubes during the irrigation season.

Annual crop coefficients, determined
from previous research using applied water and evaporation pan data, were 0.7 annually for warm-season grasses and 0.8
for cool-season grasses. Monthly crop coefficients were developed in this experiment to evaluate responses of the six turfgrass species to 60 percent and 80 percent of replacement evapotranspiration for
water conservation.

Turf performance
Overhead sprinkler irrigation provided acceptable performance of some turfgrass species, even when less than the
optimum amount of water was applied.

Subterranean irrigation did not provide
acceptable turf with the shallow-rooted
cool-season species, at the system depth
and spacing used in this study. The very
deeply rooted hybrid bermudagrass was
the best-performing species with subterranean irrigation.

Under sprinkler irrigation, there was
no significant difference in cool-season
grass performance between the 100 percent and 80 percent regimes (table 1). This could be described as a potential level of
water conservation amounting to 21.1
percent savings (77.2 inches versus 61
inches). The savings could be tenuous,
however, because of more weed and disease activity (such as Gerlachia patch on Kentucky bluegrass) when irrigated with
less than the optimum amount of water.

The 60 percent regime significantly reduced the turf quality of the three coolseason grasses tested.

In the warm-season grasses, the appearance of hybrid bermudagrass and Seashore Paspalum was not significantly
different under any of the irrigation regimes. As irrigation amounts were reduced, zoysiagrass appearance ratings declined because of nematode activity obCALIFORNIA AGRICULTURE, JULY-AUGUST 1986 19 378 Section 13, Item J.
served on the roots. Both Santa Ana hybrid bermudagrass and Adalayd (Excalibre) Seashore Paspalum had very good color, density, texture, uniformity, and
freedom from weeds and diseases, irrespective of irrigation regimes. Clearly there is potential for considerable water
savings with these grasses. This study
showed a 40 percent reduction in actual
water applied between the optimum and
lowest irrigation regime (65.5 versus 39
inches).

Because of the field plot design necessary for this study, it wasn't possible to compare statistically the turf performance results between the warm- and cool-season grasses. Hybrid bermuda and
Seashore Paspalum performed very well,
however, with 52.7 inches of water applied (60 percent irrigation regime), whereas the cool-season grasses needed
at least 82.4 inches (80 percent irrigation
regime). Thirty-six percent less water
was applied to the warm-season species
than to the cool-season species for acceptable turf quality. If applied water in the 60 percent irrigation treatment in warmseason grasses (52.7 inches) is compared with that in the 100 percent treatment in
cool-season grasses (104.4 inches), the
saving in water is 49.5 percent.

Water application
The cool-season grass in the 100 percent regime received 43 inches of water in 1982 (table 2). Warm-season grasses received only 34 inches. Rainfall of 18.45 inches occurred primarily from November to March. The soil profile held about 10 inches depth of water in the top 6 feet.

Rainfall did not appreciably affect the applied water during the primary growing season, April through November. Likewise, the 34 inches applied to the warmTABLE 1. Cool- and warm-season turfgrass appearance ratings and water applied for the duration of the study (August 1981 to December 1983).

Irrigation Water appliregime Turf appearance 8/61 - 12/83' cation (actual) ET.,...t % of ET in.

Cool season Ken. blue Per. rye Tall fesc.
100 5.5 y 6.2 y 5.8 y 104.4 77.3
80 5.3 y 5.9 y 5.7 yz 82.4 61 .O
60 4.8 z 5.0 z 5.3 z 62.7 46.4
100 6.5 ns+ 5.8 ns 5.6 x 88.4 65.5
80 6.5 5.8 4.8 y 69.4 51.4
60 6.4 5.4 4.2 z 52.7 39.0
Warm season Bermuda Paspalum Zoysia
* Rated on a scale of 1 to 9, with 1 indicating worst appearance and 9 best. Values followed by common letters are not t ETgrass equals the actual applied water divided by the extra water factor (EWF,,). which is 1.35. $ No significant difference.
significantly different at the 5% level of probability.

TABLE 2. Actual water applied in 1982 (1/1/82 to 12/31/82) and 1983 (1/1/83 to 12/31/83) Sprinkler
DlOtS
% of ET
Cool season
100
80 60
100
80 60
Warm season
1982 1983
Water applied' Rainfall Water appliedt Rainfall

43.2 35.0

26.6 34.0

27.4 21.6

18.45 38.7 31.78

31.9 24.5

33.0 25.8

19.6 ' Class A pan evaporation 55.0 inches for 1982.
t Class A pan evaporation 55.63 inches for 1983.

TABLE 3. Turfgrass crop coefficients (Kp and Kc) of warm- and cool-season grasses.

KD' Kc+ ..

Month Warm Cool Warm Cool
J
F
M
A
M
J
J
A
S
0 N
D
.44
.43
.61
.58
.63
54 57
.57
.50
.43
.46
.44
.49
.51
.60
.83
.76
.70
.75
.69
59 .60
.55
.48
.55
.54
.76
.72
.79
.68
.71
.71
.62
54 58
55 .61
.64
.75

1.04 .95
.88
.94
.86
.74
.75
.69
.60
' Monthly crop coefficient (Kp) is used with a Class A Weather Bureau evaporation pan with the equation ETgrass = t The crop coefficient Kc is used with reference evapotranspiratlon (ETo) from a ClMlS weather station with the equation ETpan X KP
ETgrass = ETo x Kc
20 CALIFORNIA AGRICULTURE, JULY-AUGUST 1986
season grasses was not appreciably affected by, nor was there evidence of, deep percolation during the primary growing
season, when only 4 inches of rain fell.

The rainfall is subtracted from the original evaporation pan reading and is therefore reasonably accounted for in the calculated applications.

In 1983, a higher than normal rainfall
of 32 inches occurred. The soil profile was
filled during the winter, however, and
only 9 inches of rain fell from April to
October 30, of which 4 inches occurred in
early April. Water moved below the root
zone only on June 29, August 29, October
5, and October 17 in all plots of 100 and 80
percent irrigation in 1983. Even during a
season of higher than normal rainfall, the
applied water, 38.7 inches in cool-season
grasses (1983), was similar to that of the
drier year (1982) with 43 inches applied.

Most of the 5 inches of implied higher use
by cool-season grasses may have moved
through deep percolation.

The water applied to warm-season
grasses was 34 inches in 1982 and 33
inches in 1983. This small difference indicates that managers can schedule carefully and conserve water in a wet or dry season.

Conclusions
The monthly crop coefficients (table 3)
calculated and used for nearly three years
proved to be very accurate for both
warm- and cool-season turfgrasses. Crop
coefficients can be used with reference
evapotranspiration from the Department
of Water Resources California Irrigation
Management Information System (CIMIS) program. Turfgrass managers can use these crop coefficients to determine
on-site water use by turfgrasses from either a Class A Weather Bureau evaporation pan or from a computerized weather station that gives reference evapotranspiration with the equation given in table 3.

In conclusion, warm-season turfgrasses have a greater potential for water conservation than do cool-season turfgrasses. Under the conditions of this study, sprinkler irrigation was superior to
subterranean irrigation for water conservation and turfgrass performance. And lastly, a well-designed, uniform irrigation
system is necessary to maximize water
conservation in turfgrass management.

Jewel1 L. Meyer is Irrigation and Soils S ecialist and
Victor A. Cibeault is Environmental drticulturist,
Cooperative Extension, University of California,
Riverside. Financial support for this study was granted by the Metropolitan Water District of South- ern California, City of Los Angeles Department of Water and Power, Municipal Water District of Orange County, and the San Diego County Water Authority. Also the support of the Southern California Turfgrass Council, the Lloyd Foundation, and the
Golf Course Superintendent's Association of Southern
California is appreciated. The authors acknowledge
the assistance of Ralph Strohman and Mark Mahody, Staff Research Associates. UC Riverside. 379
Section 13, Item J.

Water Application Efficiency,
Bill Kranz, University of Nebraska Lincoln Extension
Irrigation Specialist,
Northeast Research and Extension Center
Attachment C
380
Section 13, Item J.

Plant & Soil Sciences eLibrary (/) Lessons(/list/lesson) Collections & Categories(/list/community) Media(/view/media) LESSON: IRRIGATION HOME STUDY COURSE (/VIEW/LESSON/BDA727EB8A5A) / PAGE 8: IRRIGATION CHAPTER 8 - IRRIGATION EFFICIENCIES Irrigation Chapter 8 - Irrigation Efficiencies
Author: Bill Kranz, University of Nebraska Lincoln Extension Irrigation Specialist, Northeast Research and Extension Center, Norfolk, NE.

Water Application
The ability to manage an irrigation system is contingent on an accurate estimate of the percentage of water pumped that becomes available for crop use. No irrigation system delivers water at 100 percent efficiency. Water may be lost through delivery systems or pipelines and some water may remain in the , but not be used by the crop. Some water may run off the soil surface into lowland areas. Still other water may be lost to evaporation in the air, or from the soil and plant surfaces. Figures 8.1a and 8.1b show the major losses for sprinkler and surface irrigation systems. To know how much water to pump, these losses must be totaled and added to the amount of water needed by the crop.

Figure 8.1. a) Potential water losses during irrigation with a center pivot. b) Potential water losses during irrigation with a system.

In most cases, the goal is to insure that all areas of the field receive a amount of uniformly applied water. Consider the catch can test data shown in Figure 8.2. The cans recording application depths below the horizontal line are not receiving enough water — catches are less than the desired 0.85 inches. Another application will be needed to insure that the entire field receives at least 0.85 inches of water. This will require using more water and energy than is necessary. If this pattern occurs during each irrigation, plants in the areas receiving less than 0.85 inches eventually could experience water stress.

The cans recording application depths above the line receive at least 0.85 inches of water. Any extra water applied could lead to surface or deep .

Efficiency
soil
furrow irrigation
set
runoff percolation
381
Section 13, Item J.

Figure 8.2. Example of catch-can data from a center pivot with low pressure spray nozzle, mounted at 10 foot intervals and 7 feet above the soil surface.

Water application efficiency accounts for how uniformly the water is applied and can be used for other assessments. If the center pivot owner is trying to decide whether switching to a new sprinkler package would be economical, the change in water application efficiency could be a major factor. If water becomes limited, changing to a system with a higher water application efficiency will provide more useable water to the crop and reduce pumping costs.

To maximize irrigation water use, it must be uniformly applied in the right amount and at the right time. Reaching these objectives requires knowledge of water delivery characteristics, field soils and slopes, and the expected crop water use rates.

Mathematical relationships have been developed to help quantify the amount of applied water that becomes available for plant use.

Water application efficiency refers to the amount of water applied that is stored in the crop root zone. This value is determined by water distribution characteristics, system management, soil conditions, the crop, and weather conditions.

Water application efficiency pertains to an individual irrigation event.

Equation 8.1 is used to determine water application efficiency.

Equation 8.1 E = [Depth of water stored in the rootzone (d ) x 100 Depth of water pumped (d ) ]
where:

E = Average water application efficiency, %
Depth of water stored in the rootzone (d ) = Average depth of water stored in the rootzone, inches Depth of water pumped (d = Average depth of water delivered from source, inches Irrigation efficiency refers to the amount of water removed from the water source that is used by the crop. This value is determined by irrigation system management, water distribution characteristics, crop water use rates, weather and soil conditions. Irrigation efficiency pertains to the use of water for an entire growing season. a s
p
a
s
p)
382
Section 13, Item J.

Depth Stored
The depth of water stored in the root zone can be estimated based on field observation of what happens to the water during an application event. Field observation reports should note if runoff occurs and estimate the amount of runoff. With experience, you’ll begin to know where and when runoff is likely to occur. For example, runoff from center pivot systems will likely occur first near the outside edge of the irrigated area because the water application rate is greatest there. Other factors include low rate soils, steep slopes and lack of plant residue cover.

Another more accurate method is to record the content before and after an irrigation event using one of the methods discussed in Chapter 3, Soil Water. If the hand-feel method is used, the will need to be recorded at enough locations to develop accurate estimates of the water stored in the crop root zone. The depth of water applied is found by subtracting the reading taken before the irrigation.

Equation 8.2 d = [“After” reading – “Before” reading]
Where:
d = Depth of water stored in the rootzone
Example 8.1
A center pivot irrigation system is supplied with enough water to apply 1.1 inches of water to an irrigated area. Soil water content readings recorded before the irrigation event showed an average water content of 3.5 inches in the top 3 feet of soil.

Soil water content readings after the irrigation showed an average of 4.4 inches in the top 3 feet of soil. To find the average depth of water stored in the crop rootzone we subtract the before irrigation reading from the after irrigation reading.

Using Equation 8.2 d = [“After” reading – “Before” reading] d = [ 4.4 inches – 3.5 inches ]
d = 0.9 inches
Depth Pumped
The depth of water pumped can be determined using the procedures presented in Chapter 7, Flow Measurements and Basic Water Calculations. The information needed includes an accurate estimate of the pumping rate in gallons per minute. This information can be recorded using a flow meter installed as part of the system or periodically using an attached flow meter (ultrasonic flow meter, pilot tube type meter, etc.).

The average flow rate can be determined by recording the accumulator reading prior to and after each irrigation event.

Subtracting the reading recorded prior to the irrigation from the reading after the irrigation event will result in the total volume of water pumped. Taking the total volume and dividing by the irrigation time will give the average pumping rate. For this estimate to be accurate, the irrigation time must be accurate to the nearest hour if possible. A more precise record of the total irrigation time will improve the estimate of the pumping flow rate. (The hour meter on the motor or center pivot is accurate enough to estimate the pumping time.) Equations 8.3 and 8.4 are used to make these calculations. The following example shows how to incorporate field data into the equations.

Equation 8.3 Pumping rate = [ Reading 2 – Reading 1 ] / [ Time ] where:

Pumping rate = Water deliver rate, gallons per minute or acre-inches per minute infiltration
soil water
soil water content
s
s
s
s
s
383
Section 13, Item J.

Reading 1 = Totalizer reading before the irrigation event, gallons or acre-inches Reading 2 = Totalizer reading after the irrigation event, gallons or acre-inches Time = Time required to complete the irrigation event, minutes Example 8.2
The meter also has an accumulator at the bottom that registers total gallons pumped. Before the irrigation event, the accumulator reading was 6,553,300 gallons, and after the irrigation event the meter read 10,167,500 gallons. The irrigation event required 77 hours and 15 minutes.

Using Equation 8.3
Pumping rate = [ Reading 2-Reading 1 ] / [ Time ]
Pumping rate = [ 10,167,500 - 6,553,300 ] gallons [(77 hr x 60 min/hr ) + 15 min ] Pumping rate = [ 3,614,200 ] gallons / [ 4620 + 15 ] minutes Pumping rate = 780 gallons per minute
If the accumulator records flow in acre-inches, the same process is used unless the desire is to determine the flow rate in gallons per minute. To convert acre-inches per minute to gallons per minute, multiply the result from Equation 8.3 in acreinches per minute by 27,154 gallons per acre-inch.

To convert the flow rate in gallons per minute to the gross depth of water pumped, we use Equation 8.4. If the result from Equation 8.3 is in acre-inches per minute, the constant 27,154 gallons per acre-inch is not used.

Equation 8.4 d = [flow rate x time ] / [area irrigated x 27,154] where:
d = Depth pumped = Average depth of water pumped, inches Flow rate = Average water delivery rate, gallons per minute Time = Total irrigation time, minutes
Area irrigated = Total irrigated area, acres
27,154 = Conversion factor, gallons per acre-inch or gal / ac-in Example 8.3
Let’s assume that the field area for Example 8.2 was 123 acres. We calculated the flow rate at 780 gallons per minute and the total irrigation time at 4635 minutes. Using Equation 8.3:

Depth pumped (d ) = [ Flow rate x time ] / [ Area irrigated x 27,154 ] Depth pumped (d ) = [ 780 gal/min x 4635 minutes ] [ 123 acres x 27154 gal / ac-in ] Depth pumped (d ) = [ 3,615,300 ]gallons / [ 3,339,942 ] gallons / inch Depth pumped (d ) = 1.08 inches
p
p
p
p
p
p
384
Section 13, Item J.

To complete the calculation of the water application efficiency, use Equation 8.1 to compare the amount of water pumped with the increase in water stored in the crop rootzone.

Example 8.4
From Example 8.1 we found that 0.9 inches of water was stored in the three-foot crop rootzone. From Example 8.3 we found that 1.08 inches of water was pumped from the water source into the center pivot. To find the application efficiency we use Equation 8.1.

E = [ Depth of water stored in the rootzone (d ) x 100 Depth of water pumped (d ) ] E = [ 0.9 inches / 1.08 inches ] x 100
E = 83%
In these examples it was determined that only 83 percent of the water pumped from the irrigation source reached the soil and was usable by the crop. That means that 17 percent of the water was lost during application.

Potential Delivery Losses
The amount of water loss due to irrigation depends of the type of irrigation system — sprinkler or surface. In addition, the magnitude of each type of loss may be different. Let’s begin by listing some major sources of water loss during irrigation. To keep the losses for surface and sprinkler irrigation separate, Table 8.1 lists the potential losses for each type of system.

Table 8.1. Potential sources of water loss during an irrigation event for surface and sprinkler irrigation systems.

Sources of water losses Surface Irrigation Sprinkler irrigation Distribution system Yes
Yes
Air evaporation No Yes
Plant interception No Yes
Soil evaporation Yes Yes
Deep percolation Yes Yes
Runoff Yes Yes
Surface Irrigation Systems
The major losses for surface irrigation systems are deep percolation and surface runoff. These two losses could cause the water application efficiency to be reduced to less than 50 percent if the system is not managed properly. Ways to minimize these losses are discussed in Chapter 11, Furrow Irrigation Management (https://passel2.unl.edu/view/lesson/bda727eb8a5a/11).
a s p
a
a
385
Section 13, Item J.

Another source of water loss is in the distribution system. If the water flows across the head of the field in an open ditch, each foot of ditch loses water to soil infiltration and water surface evaporation. The best way to eliminate these losses is to transport the water through an enclosed pipeline. For many furrow irrigated fields this will require a small pumping plant to overcome the friction loss associated with forcing water through the pipeline.

Surface irrigation implies that surface evaporation will contribute to water loss. One way to limit soil evaporation loss is to wet less of the soil surface. For fields with slopes less than 1 percent, irrigating every other furrow is a viable option. This effectively cuts surface evaporation losses by nearly 50 percent without sacrificing crop production. Irrigating every other furrow also will reduce the amount of water lost to deep percolation and surface runoff.

Pipelines can have losses too. Worn gaskets or loose fitting pipeline connections could produce leaks at each joint. These losses are usually small in comparison to other losses, but by their sheer number could add up to substantial water losses.

This kind of loss is the easiest to eliminate by replacing gaskets.

Sprinkler Irrigation Systems
Sprinkler irrigation systems, especially center pivots, typically have greater water application efficiencies than surface systems. While they may have more potential sources of loss, the magnitude of each loss is generally quite low. Table

8.1 shows that sprinkler irrigation systems may experience loss from all six of the potential water loss sources while surface irrigation systems lose water from only four. This is because most sprinkler irrigation systems spray water into the air to deliver water to the entire soil surface with an upright crop canopy located between the sprinkler and soil.

Developments in sprinkler technology have reduced the amount of water lost between the sprinkler/nozzle and soil surface.

The irrigation time or the accumulated time that water is applied to the crop canopy causes the major loss during sprinkler irrigation events. Applied water evaporates off the leaves of the crop canopy. Thus, the longer water droplets are delivered to the crop, the greater the total evaporation loss. Lowering the sprinkler/nozzle pressure reduces the wetted diameter of the sprinkler/nozzle thus reducing irrigation time and total canopy evaporation losses. In addition, lower wetted diameters reduce water evaporation losses in the air and wind drift losses.

Proper management of sprinkler irrigation systems can greatly reduce deep percolation losses. An irrigation system managed to keep the soil profile completely full at all times will experience some deep percolation losses. This is because the system does not apply water at 100 percent uniformity. Some areas will receive more water than others due to sprinkler pressure differences caused by soil elevation differences. Pressure regulators or flow control nozzles help insure that water delivered to the soil surface is as uniform as possible. Other portions of the field could be affected when wind distorts the water application pattern. Such distortion can be reduced by avoiding operation when winds exceed 10 mph.

How do I Evaluate Losses?
There are two main ways to evaluate water loss during irrigation: 1) take detailed field measurements; and 2) visually estimate losses. In some cases it may be necessary to combine these methods to develop an accurate estimate of where losses occur and how significant they are to the system’s application efficiency. For example, to estimate water losses during irrigation, measure the flow rate of water entering the system with a flow meter. Visually estimate how much of the water is lost to runoff. This amount, however, will not account for other potential losses. Table 8.2 presents the potential magnitude of some of these losses for different irrigation systems. For furrow irrigation systems record how long it takes for the water to reach a certain point in the field or record flow rates into the furrow and how long it takes water to reach the end of the furrow.

When coupled with soil types and furrow slopes, a computer model can be used to estimate how efficiently the water is being applied.

Table 8.2a. Percent irrigation water losses for different furrow irrigation systems. 386
Section 13, Item J.

Type of
irrigation
system
Distribution
system
Air
evaporation
Soil
evaporation
Canopy
evaporation
Deep
percolation
Surface
runoff
Overall
efficiency
Every row 1-5 <1.0 1--5 0.0 10-20 10-35 40-75
W/Surge
valve
1-5 <1.0 1-5 0.0 5-15 5-15 60-85
W/Reuse 1-5 1-2 1-5 0.0 10-20 0 55-90
Siphon
tube
5-10 1-2 1-5 0.0 15-25 15-25 40-75
Alternate
row
1-5 <0.5 1-5 0.0 5-15 10-20 60-85
Table 8.2b. Percent irrigation water losses for different Sprinkler Irrigation systems.

Type of
irrigation
system
Distribution
system
Air
evaporation
Soil
evaporation
Canopy
evaporation
Deep
percolation
Surface
runoff
Overall
efficiency
Handmove <1.0 3-5 1-5 10-15 5-10 0-5 60-80
Solid set <1.0 3-5 1-5 10-15 0-10 0-5 60-85
Traveler <1.0 1-3 1-5 1-5 0-5 5-10 55-75
High
pressure
impact
<0.5 1-3 0-1 1-5 0-5 0-5 70-80
Low
pressure
impact
<0.5 1-3 0-1 1-3 0.5 0-10 75-85
Low
pressure
spray
<0.5 1-3 0-1 1-3 0-5 0-20 70-90
Low
pressure
bubble
<0.5 0.0 0-0.5 0.0 0-5 20-40 60-95
Drip
irrigation
<0.5 0.0 0.0 0.0 5-30 0.0 70-95
387
Section 13, Item J.
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ATTACHMENT F
Amador Regional Sanitation Agency
2024 Individual Water Balance Update
2025 Revised ARSA Detailed Water Balance Calculations
388
Section 13, Item J.
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389
Section 13, Item J.

Water Balance Update - ARSA Storage & Disposal Facilities Scenario 1: Current Flows & Facilities, Uncalibrated
February 2025 By: Bill Slenter/Steven Whittlesey, HydroScience Henderson Reservoir 392.8 ac-ft
Daily Average Wastewater Influent Flow 312,636 gpd Preston Reservoir 235.0 ac-ft 100-YR Multiplier 1.92 unitless Total System 627.8 ac-ft Pan Evap Coefficient 0.75 unitless No. Days 31 30 31 31 28 31 30 31 30 31 31 30 31 30 31 31 28 31 30 31 30 31 31 30 Units October November December January February March April May June July August September Water
Year October November December January February March April May June July August September Water
Year

CLIMATE INPUTS
Precipitation in 2.30 6.66 6.72 7.35 5.95 5.78 3.96 0.90 0.29 0.19 0.36 0.63 41.11 1.20 3.47 3.50 3.83 3.10 3.01 2.06 0.47 0.15 0.10 0.19 0.33 21.412016/2017 WY Precipitation in 6.31 2.55 5.38 15.07 4.73 3.39 4.09 0.53 1.28 0.00 0.02 0.02 43.37Pan Evaporation in 3.77 1.40 0.72 0.72 1.12 2.32 4.18 7.04 9.43 11.17 9.50 6.51 57.88 3.77 2.10 1.50 1.50 2.20 3.70 5.60 7.40 8.60 9.40 8.30 6.60 60.67Effective Water Surface Evaporation in 2.83 0.79 0.41 0.41 0.63 1.31 3.14 5.28 7.07 8.38 7.13 4.88 42.23 2.83 1.05 0.54 0.54 0.84 1.74 3.14 5.28 7.07 8.38 7.13 4.88 43.41

WASTEWATER GENERATION
Facility Wastewater Effluent (ADWF) MG 9.7 9.4 9.7 9.7 8.8 9.7 9.4 9.7 9.4 9.7 9.7 9.4 114.1 9.7 9.4 9.7 9.7 8.8 9.7 9.4 9.7 9.4 9.7 9.7 9.4 114.1I/I Contributions MG 3.0 7.4 7.5 8.1 6.7 6.5 4.7 1.6 1.0 0.9 1.1 1.4 49.9 1.9 4.2 4.2 4.6 3.8 3.7 2.8 1.2 0.9 0.8 0.9 1.1 30.1TOTAL Wastewater Effluent ac-ft 39.1 51.5 52.6 54.6 47.4 49.7 43.2 34.7 31.9 32.6 33.1 33.0 503.2 35.7 41.7 42.7 43.7 38.6 41.2 37.3 33.4 31.5 32.3 32.6 32.0 442.72016/2017 WY Effluent Flow Values ac-ft 33.8 34.3 50.6 94.9 81.3 47.6 49.4 29.5 27.3 26.5 33.8 33.8 542.8

WATERSHED CONTRIBUTING AREAS
Precipitation into Henderson Reservoir ac-ft 5.5 16.0 16.2 17.7 14.3 13.9 9.5 2.2 0.7 0.5 0.9 1.5 98.9 2.9 8.4 8.4 9.2 7.5 7.2 5.0 1.1 0.4 0.2 0.5 0.8 51.5Run-off into Henderson Reservoir ac-ft 0.8 2.4 2.4 2.7 2.2 2.1 1.4 0.3 0.1 0.1 0.1 0.2 14.8 0.4 1.3 1.3 1.4 1.1 1.1 0.7 0.2 0.1 0.0 0.1 0.1 7.7 Precipitation into Preston Forebay ac-ft 0.4 1.1 1.1 1.2 1.0 1.0 0.7 0.2 0.0 0.0 0.1 0.1 6.9 0.2 0.6 0.6 0.6 0.5 0.5 0.3 0.1 0.0 0.0 0.0 0.1 3.6 Precipitation into Preston Reservoir ac-ft 3.5 10.0 10.1 11.0 8.9 8.7 5.9 1.4 0.4 0.3 0.5 1.0 61.7 1.8 5.2 5.3 5.7 4.7 4.5 3.1 0.7 0.2 0.2 0.3 0.5 32.1 Run-off into Preston Reservoir ac-ft 2.7 7.8 7.9 8.6 7.0 6.8 4.7 1.1 0.3 0.2 0.4 0.7 48.3 1.4 4.1 4.1 4.5 3.6 3.5 2.4 0.6 0.2 0.1 0.2 0.4 25.2

STORAGE RESERVOIRS
Henderson Reservoir Volume ac-ft 27.5 56.6 125.9 196.6 270.8 333.4 392.8 392.8 336.4 238.9 130.1 41.7 27.5 35.6 86.2 138.0 191.6 237.4 283.6 281.6 218.8 122.6 27.5 27.5Henderson Reservoir Evaporation ac-ft -1.8 -0.7 -0.5 -0.7 -1.3 -2.9 -7.5 -12.6 -16.0 -16.0 -9.6 -3.6 -73.1 -1.8 -0.7 -0.6 -0.8 -1.4 -3.3 -6.6 -11.0 -12.9 -10.9 -4.4 -3.0 -57.4Henderson Reservoir Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Preston Forebay Evaporation ac-ft 0.0 -0.1 -0.1 -0.1 -0.1 -0.2 -0.5 -0.9 -1.2 -1.4 -1.2 -0.8 -6.6 -0.5 -0.2 -0.1 -0.1 -0.1 -0.3 -0.5 -0.9 -1.2 -1.4 -1.2 0.0 -6.4 Preston Forebay Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0Preston Reservoir Volume ac-ft 0.0 6.5 25.2 44.1 64.7 81.1 99.6 139.9 135.5 127.2 117.3 109.8 75.1 75.9 84.7 94.1 104.5 112.3 118.9 120.9 115.8 107.9 89.7 0.0Preston Reservoir Evaporation ac-ft 0.0 -0.2 -0.2 -0.2 -0.4 -1.1 -2.9 -6.1 -8.0 -9.1 -7.3 -4.8 -40.2 -2.2 -0.8 -0.4 -0.5 -0.8 -1.7 -3.3 -5.5 -7.2 -8.2 -6.2 0.0 -36.8Preston Reservoir Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Total Beginning Water Storage ac-ft 27.5 63.2 151.1 240.7 335.5 414.5 492.4 532.7 471.9 366.1 247.4 151.5 102.6 111.5 170.9 232.2 296.1 349.7 402.5 402.6 334.7 230.5 117.1 27.5 Reservoir Evaporation ac-ft -1.8 -1.0 -0.8 -1.0 -1.8 -4.2 -10.9 -19.5 -25.1 -26.5 -18.1 -9.2 -119.9 -4.4 -1.7 -1.1 -1.3 -2.4 -5.4 -10.3 -17.4 -21.3 -20.4 -11.8 -3.0 -100.6 Reservoir Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

LAND APPLICATION DISPOSAL DEMANDS
Bowers' Ranch ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.02016/2017 WY Bower's Ranch ac-ft -7.7 0 0 0 0 0 0 0 -24.6 -26.7 -26.7 -26.7 -112.4Hoskins' Ranch ac-ft -3.3 0.0 0.0 0.0 0.0 0.0 -2.3 -19.4 -24.7 -26.0 -23.5 -16.4 -115.5 -1.8 0.0 0.0 0.0 0.0 0.0 -3.2 -16.4 -22.8 -24.9 -23.1 -14.6 -106.72016/2017 WY Hoskin's Ranch ac-ft 0 0 0 0 0 0 0 -8.3 -27 -32.8 -26.4 -36.5 -131.0Castle Oaks Golf Course ac-ft -11.3 0.0 0.0 0.0 0.0 0.0 -11.9 -61.7 -89.4 -99.9 -89.4 -59.9 -423.4 -27.3 0.0 0.0 0.0 0.0 0.0 -35.3 -70.1 -92.4 -100.9 -91.1 -64.6 -481.7

RAW WATER MAKE-UP
Bower's Ranch Unmet Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0Hoskin's Ranch Unmet Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 COGC Unmet Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.7 48.4Total Unmet Irrigation Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.7 48.4 51.1

MONTHLY STORAGE BALANCE
Total Inflows (excluding Unmet Irrigation Demands) ac-ft 52.0 88.9 90.3 95.8 80.8 82.2 65.4 39.8 33.5 33.6 35.1 36.5 733.9 42.4 61.1 62.4 65.2 56.0 58.1 48.9 36.1 32.3 32.8 33.6 33.9 562.8 Total Inflows (including Unmet Irrigation Demands) ac-ft 52.0 88.9 90.3 95.8 80.8 82.2 65.4 39.8 33.5 33.6 35.1 36.5 733.9 42.4 61.1 62.4 65.2 56.0 58.1 48.9 36.1 32.3 32.8 36.3 82.3 613.9 Total Outflows ac-ft -16.3 -1.0 -0.7 -1.0 -1.8 -4.2 -25.1 -100.6 -139.2 -152.4 -131.0 -85.5 -658.8 -33.5 -1.7 -1.1 -1.3 -2.4 -5.4 -48.8 -103.9 -136.5 -146.2 -126.0 -82.3 -689.0 Beginning Storage Volume ac-ft 27.5 63.2 151.1 240.7 335.5 414.5 492.4 532.7 471.9 366.1 247.4 151.5 102.6 111.5 170.9 232.2 296.1 349.7 402.5 402.6 334.7 230.5 117.1 27.5 Change in Water Volume ac-ft 35.7 87.9 89.6 94.9 79.0 77.9 40.2 -60.8 -105.7 -118.8 -95.9 -49.0 8.9 59.4 61.3 63.9 53.7 52.8 0.1 -67.9 -104.2 -113.4 -89.7 0.0Final Storage Volume ac-ft 63.2 151.1 240.7 335.5 414.5 492.4 532.7 471.9 366.1 247.4 151.5 102.6 111.5 170.9 232.2 296.1 349.7 402.5 402.6 334.7 230.5 117.1 27.5 27.5 Maximum Seasonal Storage Used (ac-ft) 532.7 173.6 Mgal Maximum Seasonal Storage Used (ac-ft) 402.6 131.2 Mgal Henderson Unutilized Capacity (ac-ft) 0.0 0.0 Mgal Henderson Unutilized Capacity (ac-ft) 109.2 35.6 Mgal Preston Unutilized Capacity (ac-ft) 95.1 31.0 Mgal Preston Unutilized Capacity (ac-ft) 114.1 37.2 Mgal

WASTEWATER INFLUENT FLOW MAX STORAGE CAPACITIES OTHER INPUTS 100-YEAR ANNUAL PRECIPITATION RETURN PERIOD AVERAGE ANNUAL PRECIPITATION RETURN PERIOD

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390
Section 13, Item J.

Water Balance Update - ARSA Storage & Disposal Facilities Scenario 2a: Current Flows & Facilities, Calibrated at Avg Year Rainfall Distribution February 2025 By: Bill Slenter/Steven Whittlesey, HydroScience Henderson Reservoir 392.8 ac-ft
Daily Average Wastewater Influent Flow 312,636 gpd Preston Reservoir 235.0 ac-ft 100-YR Multiplier 1.92 unitless Total System 627.8 ac-ft Pan Evap Coefficient 0.75 unitless No. Days 31 30 31 31 28 31 30 31 30 31 31 30 31 30 31 31 28 31 30 31 30 31 31 30 Units October November December January February March April May June July August September Water
Year October November December January February March April May June July August September Water
Year

CLIMATE INPUTS
Precipitation - Calibrated Avg Year Distribution in 2.30 6.66 6.72 7.35 5.95 5.78 3.96 0.90 0.29 0.19 0.36 0.63 41.11 1.20 3.47 3.50 3.83 3.10 3.01 2.06 0.47 0.15 0.10 0.19 0.33 21.41Precipitation - Calibrated & 2016/207 Distribution in 5.98 2.42 5.10 14.28 4.48 3.21 3.88 0.50 1.21 0.00 0.02 0.022016/2017 WY Precipitation in 6.31 2.55 5.38 15.07 4.73 3.39 4.09 0.53 1.28 0.00 0.02 0.02 43.37Pan Evaporation in 3.77 1.40 0.72 0.72 1.12 2.32 4.18 7.04 9.43 11.17 9.50 6.51 57.88 3.77 2.10 1.50 1.50 2.20 3.70 5.60 7.40 8.60 9.40 8.30 6.60 60.67Effective Water Surface Evaporation in 2.83 0.79 0.41 0.41 0.63 1.31 3.14 5.28 7.07 8.38 7.13 4.88 42.23 2.83 1.05 0.54 0.54 0.84 1.74 3.14 5.28 7.07 8.38 7.13 4.88 43.41

WASTEWATER GENERATION
Facility Wastewater Effluent (ADWF) MG 9.7 9.4 9.7 9.7 8.8 9.7 9.4 9.7 9.4 9.7 9.7 9.4 114.1 9.7 9.4 9.7 9.7 8.8 9.7 9.4 9.7 9.4 9.7 9.7 9.4 114.1I/I Contributions - Climate Calibration Only MG 3.0 7.4 7.5 8.1 6.7 6.5 4.7 1.6 1.0 0.9 1.1 1.4 49.9 1.9 4.2 4.2 4.6 3.8 3.7 2.8 1.2 0.9 0.8 0.9 1.1I/I Contributions - Calibrated (25% Factor Applied) MG 3.0 7.4 9.3 10.1 8.4 8.1 5.9 1.6 1.0 0.9 1.1 1.4 58.2 1.9 4.2 5.3 5.7 4.8 4.7 3.5 1.2 0.9 0.8 0.9 1.1 34.9TOTAL Wastewater Effluent - Climate Calibration Only ac-ft 39.1 51.5 52.6 54.6 47.4 49.7 43.2 34.7 31.9 32.6 33.1 33.0 503.2 35.7 41.7 42.7 43.7 38.6 41.2 37.3 33.4 31.5 32.3 32.6 32.0 442.7TOTAL Wastewater Effluent ac-ft 39.1 51.5 58.3 60.8 52.5 54.7 46.8 34.7 31.9 32.6 33.1 33.0 528.9 35.7 41.7 46.0 47.2 41.6 44.1 39.5 33.4 31.5 32.3 32.6 32.0 457.42016/2017 WY Effluent Flow Values ac-ft 33.8 34.3 50.6 94.9 81.3 47.6 49.4 29.5 27.3 26.5 33.8 33.8 542.8

WATERSHED CONTRIBUTING AREAS
Precipitation into Henderson Reservoir ac-ft 5.5 16.0 16.2 17.7 14.3 13.9 9.5 2.2 0.7 0.5 0.9 1.5 98.9 2.9 8.4 8.4 9.2 7.5 7.2 5.0 1.1 0.4 0.2 0.5 0.8 51.5Run-off into Henderson Reservoir ac-ft 0.8 2.4 2.4 2.7 2.2 2.1 1.4 0.3 0.1 0.1 0.1 0.2 14.8 0.4 1.3 1.3 1.4 1.1 1.1 0.7 0.2 0.1 0.0 0.1 0.1 7.7Precipitation into Preston Forebay ac-ft 0.4 1.1 1.1 1.2 1.0 1.0 0.7 0.2 0.0 0.0 0.1 0.1 6.9 0.2 0.6 0.6 0.6 0.5 0.5 0.3 0.1 0.0 0.0 0.0 0.1 3.6Precipitation into Preston Reservoir ac-ft 3.5 10.0 10.1 11.0 8.9 8.7 5.9 1.4 0.4 0.3 0.5 1.0 61.7 1.8 5.2 5.3 5.7 4.7 4.5 3.1 0.7 0.2 0.2 0.3 0.5 32.1Run-off into Preston Reservoir ac-ft 2.7 7.8 7.9 8.6 7.0 6.8 4.7 1.1 0.3 0.2 0.4 0.7 48.3 1.4 4.1 4.1 4.5 3.6 3.5 2.4 0.6 0.2 0.1 0.2 0.4 25.2

STORAGE RESERVOIRS
Henderson Reservoir Volume ac-ft 27.5 56.6 125.9 202.3 282.7 350.4 392.8 392.8 336.4 238.9 130.1 41.7 27.5 35.6 86.2 141.3 198.4 247.0 296.1 296.1 233.0 136.4 31.6 27.5Henderson Reservoir Evaporation ac-ft -1.8 -0.7 -0.5 -0.7 -1.3 -3.0 -7.5 -12.6 -16.0 -16.0 -9.6 -3.6 -73.2 -1.8 -0.7 -0.6 -0.8 -1.4 -3.4 -6.7 -11.3 -13.4 -11.6 -4.7 -3.0 -59.3Henderson Reservoir Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Preston Forebay Evaporation ac-ft 0.0 -0.1 -0.1 -0.1 -0.1 -0.2 -0.5 -0.9 -1.2 -1.4 -1.2 -0.8 -6.6 -0.5 -0.2 -0.1 -0.1 -0.1 -0.3 -0.5 -0.9 -1.2 -1.4 -1.2 -0.8 -7.2Preston Forebay Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Preston Reservoir Volume ac-ft 0.0 6.5 25.2 44.1 64.7 81.1 121.6 165.0 160.1 151.0 140.1 131.8 96.5 96.8 105.6 114.9 125.2 132.9 139.3 141.0 135.4 126.7 116.5 26.9 Preston Reservoir Evaporation ac-ft 0.0 -0.2 -0.2 -0.2 -0.4 -1.1 -3.3 -6.6 -8.7 -10.0 -8.2 -5.4 -44.3 -2.6 -1.0 -0.5 -0.5 -0.9 -1.9 -3.6 -6.1 -8.0 -9.0 -7.3 -1.9 -43.3 Preston Reservoir Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0Total Beginning Water Storage ac-ft 27.5 63.2 151.1 246.4 347.4 431.5 514.4 557.8 496.4 389.9 270.2 173.5 124.0 132.5 191.8 256.2 323.5 380.0 435.3 437.1 368.4 263.1 148.1 54.4 Total Reservoir Evaporation ac-ft -1.8 -1.0 -0.8 -1.0 -1.9 -4.3 -11.3 -20.1 -25.9 -27.5 -18.9 -9.8 -124.1 -4.8 -1.9 -1.2 -1.4 -2.5 -5.6 -10.8 -18.2 -22.5 -22.0 -13.2 -5.8 -109.8 Total Reservoir Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

UNMET IRRIGATION DEMANDS
Bower's Ranch Unmet Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0Hoskin's Ranch Unmet Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 COGC Unmet Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 24.2Total Unmet Irrigation Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 24.2 24.2

MONTHLY STORAGE BALANCE
Total Inflows (excluding Unmet Irrigation Demands) ac-ft 52.0 88.9 96.0 102.0 85.9 87.1 68.9 39.8 33.5 33.6 35.1 36.5 759.5 42.4 61.1 65.6 68.7 58.9 61.0 51.0 36.1 32.3 32.8 33.6 33.9 577.5 Total Inflows (including Unmet Irrigation Demands) ac-ft 52.0 88.9 96.0 102.0 85.9 87.1 68.9 39.8 33.5 33.6 35.1 36.5 759.5 42.4 61.1 65.6 68.7 58.9 61.0 51.0 36.1 32.3 32.8 33.6 58.1 601.8 Total Outflows ac-ft -16.3 -1.0 -0.7 -1.0 -1.8 -4.3 -25.5 -101.2 -140.0 -153.4 -131.8 -86.1 -663.1 -33.9 -1.8 -1.2 -1.4 -2.5 -5.6 -49.3 -104.7 -137.7 -147.8 -127.3 -85.0 -698.2Beginning Storage Volume ac-ft 27.5 63.2 151.1 246.4 347.4 431.5 514.4 557.8 496.4 389.9 270.2 173.5 124.0 132.5 191.8 256.2 323.5 380.0 435.3 437.1 368.4 263.1 148.1 54.4 Change in Water Volume ac-ft 35.7 87.9 95.3 101.0 84.1 82.9 43.4 -61.4 -106.5 -119.7 -96.7 -49.5 8.5 59.3 64.4 67.3 56.5 55.4 1.8 -68.7 -105.4 -115.0 -93.7 -26.9Final Storage Volume ac-ft 63.2 151.1 246.4 347.4 431.5 514.4 557.8 496.4 389.9 270.2 173.5 124.0 132.5 191.8 256.2 323.5 380.0 435.3 437.1 368.4 263.1 148.1 54.4 27.5 Maximum Seasonal Storage Used (ac-ft) 557.8 181.8 Mgal Maximum Seasonal Storage Used (ac-ft) 437.1 142.4 Mgal Henderson Unutilized Capacity (ac-ft) 0.0 0.0 Mgal Henderson Unutilized Capacity (ac-ft) 96.7 31.5 Mgal Preston Unutilized Capacity (ac-ft) 70.0 22.8 Mgal Preston Unutilized Capacity (ac-ft) 94.0 30.6 Mgal

WASTEWATER INFLUENT FLOW MAX STORAGE CAPACITIES OTHER INPUTS 100-YEAR ANNUAL PRECIPITATION RETURN PERIOD AVERAGE ANNUAL PRECIPITATION RETURN PERIOD

Page 2 of 5 ends

391
Section 13, Item J.

Water Balance Update - ARSA Storage & Disposal Facilities Scenario 2b: Current Flows & Facilities, Calibrated at 2016/17 Rainfall Distribution February 2025 By: Bill Slenter/Steven Whittlesey, HydroScience Henderson Reservoir 392.8 ac-ft
Daily Average Wastewater Influent Flow 312,636 gpd Preston Reservoir 235.0 ac-ft 100-YR Multiplier 1.92 unitless Total System 627.8 ac-ft Pan Evap Coefficient 0.75 unitless No. Days 31 30 31 31 28 31 30 31 30 31 31 30 31 30 31 31 28 31 30 31 30 31 31 30 Units October November December January February March April May June July August September Water
Year October November December January February March April May June July August September Water
Year

CLIMATE INPUTS
Precipitation - Calibrated & 2016/17 Distribution in 5.98 2.42 5.10 14.28 4.48 3.21 3.88 0.50 1.21 0.00 0.02 0.02 41.11 1.20 3.47 3.50 3.83 3.10 3.01 2.06 0.47 0.15 0.10 0.19 0.33 21.41Precipitation - Calibrated & 2016/207 Distribution in 5.98 2.42 5.10 14.28 4.48 3.21 3.88 0.50 1.21 0.00 0.02 0.022016/2017 WY Precipitation in 6.31 2.55 5.38 15.07 4.73 3.39 4.09 0.53 1.28 0.00 0.02 0.02 43.37Pan Evaporation in 3.77 1.40 0.72 0.72 1.12 2.32 4.18 7.04 9.43 11.17 9.50 6.51 57.88 3.77 2.10 1.50 1.50 2.20 3.70 5.60 7.40 8.60 9.40 8.30 6.60 60.67Effective Water Surface Evaporation in 2.83 0.79 0.41 0.41 0.63 1.31 3.14 5.28 7.07 8.38 7.13 4.88 42.23 2.83 1.05 0.54 0.54 0.84 1.74 3.14 5.28 7.07 8.38 7.13 4.88 43.41

WASTEWATER GENERATION
Facility Wastewater Effluent (ADWF) MG 9.7 9.4 9.7 9.7 8.8 9.7 9.4 9.7 9.4 9.7 9.7 9.4 114.1 9.7 9.4 9.7 9.7 8.8 9.7 9.4 9.7 9.4 9.7 9.7 9.4 114.1I/I Contributions - Climate Calibration Only MG 6.7 3.1 5.8 15.0 5.2 3.9 4.6 1.2 1.9 0.7 0.7 0.7 49.9 1.9 4.2 4.2 4.6 3.8 3.7 2.8 1.2 0.9 0.8 0.9 1.1 30.1I/I Contributions - Calibrated (25% Factor Applied) MG 6.7 3.1 7.3 18.8 6.5 4.9 5.8 1.2 1.9 0.7 0.7 0.7 58.5 1.9 4.2 5.3 5.7 4.8 4.7 3.5 1.2 0.9 0.8 0.9 1.1 34.9TOTAL Wastewater Effluent - Climate Calibration Only ac-ft 50.3 38.4 47.6 75.8 42.9 41.8 42.9 33.5 34.7 32.0 32.0 31.1 503.2 35.7 41.7 42.7 43.7 38.6 41.2 37.3 33.4 31.5 32.3 32.6 32.0 442.7TOTAL Wastewater Effluent ac-ft 50.3 38.4 52.1 87.4 46.9 44.9 46.5 33.5 34.7 32.0 32.0 31.1 529.8 35.7 41.7 46.0 47.2 41.6 44.1 39.5 33.4 31.5 32.3 32.6 32.0 457.42016/2017 WY Effluent Flow Values ac-ft 33.8 34.3 50.6 94.9 81.3 47.6 49.4 29.5 27.3 26.5 33.8 33.8 542.8

WATERSHED CONTRIBUTING AREAS
Precipitation into Henderson Reservoir ac-ft 14.4 5.8 12.3 34.4 10.8 7.7 9.3 1.2 2.9 0.0 0.0 0.0 98.9 2.9 8.4 8.4 9.2 7.5 7.2 5.0 1.1 0.4 0.2 0.5 0.8 51.5Run-off into Henderson Reservoir ac-ft 2.2 0.9 1.8 5.2 1.6 1.2 1.4 0.2 0.4 0.0 0.0 0.0 14.8 0.4 1.3 1.3 1.4 1.1 1.1 0.7 0.2 0.1 0.0 0.1 0.1 7.7Precipitation into Preston Forebay ac-ft 1.0 0.4 0.8 2.4 0.7 0.5 0.6 0.1 0.2 0.0 0.0 0.0 6.9 0.2 0.6 0.6 0.6 0.5 0.5 0.3 0.1 0.0 0.0 0.0 0.1 3.6Precipitation into Preston Reservoir ac-ft 9.0 3.6 7.6 21.4 6.7 4.8 5.8 0.8 1.8 0.0 0.0 0.0 61.7 1.8 5.2 5.3 5.7 4.7 4.5 3.1 0.7 0.2 0.2 0.3 0.5 32.1Run-off into Preston Reservoir ac-ft 7.0 2.8 6.0 16.8 5.3 3.8 4.6 0.6 1.4 0.0 0.0 0.0 48.3 1.4 4.1 4.1 4.5 3.6 3.5 2.4 0.6 0.2 0.1 0.2 0.4 25.2

STORAGE RESERVOIRS
Henderson Reservoir Volume ac-ft 27.5 78.1 122.4 188.2 314.4 372.3 392.8 392.8 334.0 242.0 132.0 41.5 27.5 35.6 86.2 141.3 198.4 247.0 296.1 296.1 233.0 136.4 31.6 27.5Henderson Reservoir Evaporation ac-ft -1.8 -0.8 -0.5 -0.7 -1.4 -3.1 -7.5 -12.6 -15.9 -16.2 -9.7 -3.6 -73.6 -1.8 -0.7 -0.6 -0.8 -1.4 -3.4 -6.7 -11.3 -13.4 -11.6 -4.7 -3.0 -59.3Henderson Reservoir Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Preston Forebay Evaporation ac-ft 0.0 -0.1 -0.1 -0.1 -0.1 -0.2 -0.5 -0.9 -1.2 -1.4 -1.2 -0.8 -6.6 -0.5 -0.2 -0.1 -0.1 -0.1 -0.3 -0.5 -0.9 -1.2 -1.4 -1.2 -0.8 -7.2Preston Forebay Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Preston Reservoir Volume ac-ft 0.0 17.0 23.5 37.8 78.1 90.3 128.3 170.9 164.7 158.1 146.4 136.9 95.9 96.3 105.0 114.4 124.6 132.4 138.7 140.5 134.9 126.2 116.0 26.4Preston Reservoir Evaporation ac-ft 0.0 -0.2 -0.1 -0.2 -0.5 -1.1 -3.4 -6.8 -8.9 -10.3 -8.4 -5.5 -45.4 -2.6 -1.0 -0.5 -0.5 -0.9 -1.9 -3.6 -6.1 -7.9 -9.0 -7.3 -1.9 -43.2 Preston Reservoir Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0Total Beginning Water Storage ac-ft 27.5 95.1 145.9 225.9 392.5 462.6 521.1 563.7 498.7 400.1 278.4 178.4 123.4 131.9 191.2 255.6 323.0 379.4 434.8 436.6 367.9 262.5 147.6 53.9 Total Reservoir Evaporation ac-ft -1.8 -1.2 -0.7 -0.9 -2.0 -4.4 -11.4 -20.2 -26.0 -27.8 -19.2 -9.9 -125.6 -4.8 -1.8 -1.2 -1.4 -2.5 -5.6 -10.8 -18.2 -22.5 -22.0 -13.1 -5.8 -109.7 Total Reservoir Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

UNMET IRRIGATION DEMANDS
Bower's Ranch Unmet Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0Hoskin's Ranch Unmet Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 COGC Unmet Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 24.7Total Unmet Irrigation Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 24.7 24.7

MONTHLY STORAGE BALANCE
Total Inflows (excluding Unmet Irrigation Demands) ac-ft 83.9 52.0 80.7 167.5 72.0 62.9 68.2 36.3 41.5 32.0 32.1 31.2 760.4 42.4 61.1 65.6 68.7 58.9 61.0 51.0 36.1 32.3 32.8 33.6 33.9 577.5 Total Inflows (including Unmet Irrigation Demands) ac-ft 83.9 52.0 80.7 167.5 72.0 62.9 68.2 36.3 41.5 32.0 32.1 31.2 760.4 42.4 61.1 65.6 68.7 58.9 61.0 51.0 36.1 32.3 32.8 33.6 58.6 602.2 Total Outflows ac-ft -16.3 -1.2 -0.7 -0.9 -2.0 -4.4 -25.6 -101.3 -140.1 -153.7 -132.1 -86.2 -664.5 -33.9 -1.8 -1.2 -1.4 -2.5 -5.6 -49.3 -104.7 -137.7 -147.8 -127.3 -85.0 -698.1Beginning Storage Volume ac-ft 27.5 95.1 145.9 225.9 392.5 462.6 521.1 563.7 498.7 400.1 278.4 178.4 123.4 131.9 191.2 255.6 323.0 379.4 434.8 436.6 367.9 262.5 147.6 53.9 Change in Water Volume ac-ft 67.6 50.8 80.0 166.6 70.1 58.5 42.6 -65.0 -98.6 -121.8 -100.0 -55.0 8.5 59.3 64.4 67.3 56.5 55.4 1.8 -68.7 -105.3 -114.9 -93.7 -26.4Final Storage Volume ac-ft 95.1 145.9 225.9 392.5 462.6 521.1 563.7 498.7 400.1 278.4 178.4 123.4 131.9 191.2 255.6 323.0 379.4 434.8 436.6 367.9 262.5 147.6 53.9 27.5 Maximum Seasonal Storage Used (ac-ft) 563.7 183.7 Mgal Maximum Seasonal Storage Used (ac-ft) 436.6 142.3 Mgal Henderson Unutilized Capacity (ac-ft) 0.0 0.0 Mgal Henderson Unutilized Capacity (ac-ft) 96.7 31.5 Mgal Preston Unutilized Capacity (ac-ft) 64.1 20.9 Mgal Preston Unutilized Capacity (ac-ft) 94.5 30.8 Mgal

WASTEWATER INFLUENT FLOW MAX STORAGE CAPACITIES OTHER INPUTS 100-YEAR ANNUAL PRECIPITATION RETURN PERIOD AVERAGE ANNUAL PRECIPITATION RETURN PERIOD

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Section 13, Item J.

Water Balance Update - ARSA Storage & Disposal Facilities Scenario 3a: Future Flows & Facilities, Calibrated at Avg Year Rainfall Distribution February 2025 By: Bill Slenter/Steven Whittlesey, HydroScience Henderson Reservoir 392.8 ac-ft I/I Reduction Factor 0.00% unitless Daily Average Wastewater Influent Flow 319,420 gpd Preston Reservoir 235.0 ac-ft 100-YR Multiplier 1.92 unitless Total System 627.8 ac-ft Pan Evap Coefficient 0.75 unitless No. Days 31 30 31 31 28 31 30 31 30 31 31 30 31 30 31 31 28 31 30 31 30 31 31 30 Units October November December January February March April May June July August September Water
Year October November December January February March April May June July August September Water
Year

CLIMATE INPUTS
Precipitation - Calibrated Avg Year Distribution in 2.30 6.66 6.72 7.35 5.95 5.78 3.96 0.90 0.29 0.19 0.36 0.63 41.11 1.20 3.47 3.50 3.83 3.10 3.01 2.06 0.47 0.15 0.10 0.19 0.33 21.41Precipitation - Calibrated & 2016/17 Distribution in 5.98 2.42 5.10 14.28 4.48 3.21 3.88 0.50 1.21 0.00 0.02 0.02 41.11 2016/2017 WY Precipitation in 6.31 2.55 5.38 15.07 4.73 3.39 4.09 0.53 1.28 0.00 0.02 0.02 43.37 Pan Evaporation in 3.77 1.40 0.72 0.72 1.12 2.32 4.18 7.04 9.43 11.17 9.50 6.51 57.88 3.77 2.10 1.50 1.50 2.20 3.70 5.60 7.40 8.60 9.40 8.30 6.60 60.67 Effective Water Surface Evaporation in 2.83 0.79 0.41 0.41 0.63 1.31 3.14 5.28 7.07 8.38 7.13 4.88 42.23 2.83 1.05 0.54 0.54 0.84 1.74 3.14 5.28 7.07 8.38 7.13 4.88 43.41

WASTEWATER GENERATION
Facility Wastewater Effluent (ADWF) MG 9.9 9.6 9.9 9.9 8.9 9.9 9.6 9.9 9.6 9.9 9.9 9.6 116.6 9.9 9.6 9.9 9.9 8.9 9.9 9.6 9.9 9.6 9.9 9.9 9.6 116.6I/I Contributions - Calibrated MG 3.0 7.4 9.3 10.1 8.4 8.1 5.9 1.6 1.0 0.9 1.1 1.4 58.2 1.9 4.2 5.3 5.7 4.8 4.7 3.5 1.2 0.9 0.8 0.9 1.1 34.9 TOTAL Wastewater Effluent ac-ft 39.7 52.1 59.0 61.41 53.1 55.4 47.4 35.4 32.5 33.2 33.7 33.6 536.5 36.3 42.3 46.6 47.9 42.1 44.7 40.1 34.1 32.1 32.9 33.2 32.7 465.0 2016/2017 WY Effluent Flow Values ac-ft 33.8 34.3 50.6 94.9 81.3 47.6 49.4 29.5 27.3 26.5 33.8 33.8 542.8

WATERSHED CONTRIBUTING AREAS
Precipitation into Henderson Reservoir ac-ft 5.5 16.0 16.2 17.7 14.3 13.9 9.5 2.2 0.7 0.5 0.9 1.5 98.9 2.9 8.4 8.4 9.2 7.5 7.2 5.0 1.1 0.4 0.2 0.5 0.8 51.5Run-off into Henderson Reservoir ac-ft 0.8 2.4 2.4 2.7 2.2 2.1 1.4 0.3 0.1 0.1 0.1 0.2 14.8 0.4 1.3 1.3 1.4 1.1 1.1 0.7 0.2 0.1 0.0 0.1 0.1 7.7Precipitation into Preston Forebay ac-ft 0.4 1.1 1.1 1.2 1.0 1.0 0.7 0.2 0.0 0.0 0.1 0.1 6.9 0.2 0.6 0.6 0.6 0.5 0.5 0.3 0.1 0.0 0.0 0.0 0.1 3.6Precipitation into Preston Reservoir ac-ft 3.5 10.0 10.1 11.0 8.9 8.7 5.9 1.4 0.4 0.3 0.5 1.0 61.7 1.8 5.2 5.3 5.7 4.7 4.5 3.1 0.7 0.2 0.2 0.3 0.5 32.1Run-off into Preston Reservoir ac-ft 2.7 7.8 7.9 8.6 7.0 6.8 4.7 1.1 0.3 0.2 0.4 0.7 48.3 1.4 4.1 4.1 4.5 3.6 3.5 2.4 0.6 0.2 0.1 0.2 0.4 25.2

STORAGE RESERVOIRS
Henderson Reservoir Volume ac-ft 27.5 57.3 127.2 204.2 285.3 353.5 392.8 392.8 337.0 240.2 132.0 44.1 27.5 36.3 87.4 143.2 200.9 250.2 299.8 300.4 237.9 141.7 37.3 27.5 Henderson Reservoir Evaporation ac-ft -1.8 -0.7 -0.5 -0.7 -1.3 -3.0 -7.5 -12.6 -16.0 -16.1 -9.7 -3.7 -73.5 -1.8 -0.7 -0.6 -0.8 -1.5 -3.4 -6.7 -11.4 -13.5 -11.8 -5.0 -3.0 -60.2Henderson Reservoir Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Preston Forebay Evaporation ac-ft 0.0 -0.1 -0.1 -0.1 -0.1 -0.2 -0.5 -0.9 -1.2 -1.4 -1.2 -0.8 -6.6 -0.5 -0.2 -0.1 -0.1 -0.1 -0.3 -0.5 -0.9 -1.2 -1.4 -1.2 -0.8 -7.2 Preston Forebay Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Preston Reservoir Volume ac-ft 0.0 6.5 25.2 44.1 64.7 81.1 125.3 169.3 164.3 155.1 144.1 135.6 103.2 103.4 112.1 121.4 131.7 139.4 145.7 147.3 141.6 132.6 122.2 38.4 Preston Reservoir Evaporation ac-ft 0.0 -0.2 -0.2 -0.2 -0.4 -1.1 -3.4 -6.7 -8.9 -10.2 -8.3 -5.5 -45.0 -2.7 -1.0 -0.5 -0.6 -0.9 -2.0 -3.7 -6.2 -8.2 -9.3 -7.5 -2.4 -45.0 Preston Reservoir Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Total Beginning Water Storage ac-ft 27.5 63.8 152.3 248.3 350.0 434.6 518.1 562.1 501.3 395.3 276.0 179.7 130.6 139.7 199.6 264.6 332.6 389.6 445.5 447.7 379.5 274.4 159.5 65.9Total Reservoir Evaporation ac-ft -1.8 -1.0 -0.8 -1.0 -1.9 -4.3 -11.4 -20.2 -26.0 -27.7 -19.1 -10.0 -125.0 -4.9 -1.9 -1.2 -1.4 -2.5 -5.7 -10.9 -18.5 -22.9 -22.5 -13.7 -6.2 -112.4 Total Reservoir Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

LAND APPLICATION DISPOSAL DEMANDS
Bowers' Ranch ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.02016/2017 WY Bower's Ranch ac-ft -7.7 0 0 0 0 0 0 0 -24.6 -26.7 -26.7 -26.7 -112.4Hoskins' Ranch ac-ft -3.3 0.0 0.0 0.0 0.0 0.0 -2.3 -19.4 -24.7 -26.0 -23.5 -16.4 -115.5 -1.8 0.0 0.0 0.0 0.0 0.0 -3.2 -16.4 -22.8 -24.9 -23.1 -14.6 -106.72016/2017 WY Hoskin's Ranch ac-ft 0 0 0 0 0 0 0 -8.3 -27 -32.8 -26.4 -36.5 -131.0COWRF and Castle Oaks Golf Course ac-ft -11.3 0.0 0.0 0.0 0.0 0.0 -11.9 -61.7 -89.4 -99.9 -89.4 -59.9 -423.4 -27.3 0.0 0.0 0.0 0.0 0.0 -35.3 -70.1 -92.4 -100.9 -91.1 -64.6 -481.7

UNMET IRRIGATION DEMANDS
Bower's Ranch Unmet Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Hoskin's Ranch Unmet Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 COGC Unmet Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 12.5Total Unmet Irrigation Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 12.5 12.5

MONTHLY STORAGE BALANCE
Total Inflows (excluding Unmet Irrigation Demands) ac-ft 52.6 89.5 96.7 102.7 86.5 87.8 69.6 40.5 34.1 34.3 35.8 37.1 767.1 43.0 61.8 66.3 69.4 59.5 61.6 51.7 36.7 32.9 33.5 34.3 34.5 585.1 Total Inflows (including Unmet Irrigation Demands) ac-ft 52.6 89.5 96.7 102.7 86.5 87.8 69.6 40.5 34.1 34.3 35.8 37.1 767.1 43.0 61.8 66.3 69.4 59.5 61.6 51.7 36.7 32.9 33.5 34.3 47.0 597.7 Total Outflows ac-ft -16.3 -1.0 -0.7 -1.0 -1.8 -4.3 -25.6 -101.3 -140.2 -153.6 -132.0 -86.2 -664.0 -34.0 -1.9 -1.2 -1.4 -2.5 -5.7 -49.4 -105.0 -138.0 -148.3 -127.9 -85.5 -700.8Beginning Storage Volume ac-ft 27.5 63.8 152.3 248.3 350.0 434.6 518.1 562.1 501.3 395.3 276.0 179.7 130.6 139.7 199.6 264.6 332.6 389.6 445.5 447.7 379.5 274.4 159.5 65.9Change in Water Volume ac-ft 36.3 88.5 95.9 101.7 84.6 83.5 44.0 -60.8 -106.0 -119.3 -96.3 -49.1 9.0 59.9 65.1 68.0 57.0 55.9 2.2 -68.3 -105.1 -114.8 -93.6 -38.4 Final Storage Volume ac-ft 63.8 152.3 248.3 350.0 434.6 518.1 562.1 501.3 395.3 276.0 179.7 130.6 139.7 199.6 264.6 332.6 389.6 445.5 447.7 379.5 274.4 159.5 65.9 27.5 Maximum Seasonal Storage Used (ac-ft) 562.1 183.2 Mgal Maximum Seasonal Storage Used (ac-ft) 447.7 145.9 Mgal Henderson Unutilized Capacity (ac-ft) 0.0 0.0 Mgal Henderson Unutilized Capacity (ac-ft) 92.4 30.1 Mgal Preston Unutilized Capacity (ac-ft) 65.7 21.4 Mgal Preston Unutilized Capacity (ac-ft) 87.7 28.6 Mgal

WASTEWATER INFLUENT FLOW MAX STORAGE CAPACITIES OTHER INPUTS 100-YEAR ANNUAL PRECIPITATION RETURN PERIOD AVERAGE ANNUAL PRECIPITATION RETURN PERIOD

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Section 13, Item J.

Water Balance Update - ARSA Storage & Disposal Facilities Scenario 3b: Future Flows & Facilities, Calibrated at 2016/17 Rainfall Distribution February 2025 By: Bill Slenter/Steven Whittlesey, HydroScience Henderson Reservoir 392.8 ac-ft I/I Reduction Factor 0.00% unitless Daily Average Wastewater Influent Flow 319,420 gpd Preston Reservoir 235.0 ac-ft 100-YR Multiplier 1.92 unitless Total System 627.8 ac-ft Pan Evap Coefficient 0.75 unitless No. Days 31 30 31 31 28 31 30 31 30 31 31 30 31 30 31 31 28 31 30 31 30 31 31 30 Units October November December January February March April May June July August September Water
Year October November December January February March April May June July August September Water
Year

CLIMATE INPUTS
Precipitation - Calibrated & 2016/17 Distribution in 5.98 2.42 5.10 14.28 4.48 3.21 3.88 0.50 1.21 0.00 0.02 0.02 41.11 1.20 3.47 3.50 3.83 3.10 3.01 2.06 0.47 0.15 0.10 0.19 0.33 21.41Precipitation - Calibrated & 2016/17 Distribution in 5.98 2.42 5.10 14.28 4.48 3.21 3.88 0.50 1.21 0.00 0.02 0.022016/2017 WY Precipitation in 6.31 2.55 5.38 15.07 4.73 3.39 4.09 0.53 1.28 0.00 0.02 0.02 43.37Pan Evaporation in 3.77 1.40 0.72 0.72 1.12 2.32 4.18 7.04 9.43 11.17 9.50 6.51 57.88 3.77 2.10 1.50 1.50 2.20 3.70 5.60 7.40 8.60 9.40 8.30 6.60 60.67 Effective Water Surface Evaporation in 2.83 0.79 0.41 0.41 0.63 1.31 3.14 5.28 7.07 8.38 7.13 4.88 42.23 2.83 1.05 0.54 0.54 0.84 1.74 3.14 5.28 7.07 8.38 7.13 4.88 43.41

WASTEWATER GENERATION
Facility Wastewater Effluent (ADWF) MG 9.9 9.6 9.9 9.9 8.9 9.9 9.6 9.9 9.6 9.9 9.9 9.6 116.6 9.9 9.6 9.9 9.9 8.9 9.9 9.6 9.9 9.6 9.9 9.9 9.6 116.6I/I Contributions - Calibrated MG 6.7 3.1 7.3 18.8 6.5 4.9 5.8 1.2 1.9 0.7 0.7 0.7 58.5 1.9 4.2 5.3 5.7 4.8 4.7 3.5 1.2 0.9 0.8 0.9 1.1 34.9 TOTAL Wastewater Effluent ac-ft 51.0 39.1 52.8 88.02 47.4 45.5 47.1 34.2 35.4 32.6 32.7 31.7 537.4 36.3 42.3 46.6 47.9 42.1 44.7 40.1 34.1 32.1 32.9 33.2 32.7 465.0 2016/2017 WY Effluent Flow Values ac-ft 33.8 34.3 50.6 94.9 81.3 47.6 49.4 29.5 27.3 26.5 33.8 33.8 542.8

STORAGE RESERVOIRS
Henderson Reservoir Volume ac-ft 27.5 78.8 123.7 190.1 317.0 375.4 392.8 392.8 334.7 243.3 133.8 43.9 27.5 36.3 87.4 143.2 200.9 250.2 299.8 300.4 237.9 141.7 37.3 27.5 Henderson Reservoir Evaporation ac-ft -1.8 -0.8 -0.5 -0.7 -1.4 -3.1 -7.5 -12.6 -15.9 -16.2 -9.7 -3.7 -73.8 -1.8 -0.7 -0.6 -0.8 -1.5 -3.4 -6.7 -11.4 -13.5 -11.8 -5.0 -3.0 -60.2Henderson Reservoir Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Preston Forebay Evaporation ac-ft 0.0 -0.1 -0.1 -0.1 -0.1 -0.2 -0.5 -0.9 -1.2 -1.4 -1.2 -0.8 -6.6 -0.5 -0.2 -0.1 -0.1 -0.1 -0.3 -0.5 -0.9 -1.2 -1.4 -1.2 -0.8 -7.2 Preston Forebay Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Preston Reservoir Volume ac-ft 0.0 17.0 23.5 37.8 78.1 90.3 132.0 175.2 168.9 162.2 150.4 140.7 102.6 102.9 111.6 120.9 131.1 138.9 145.2 146.8 141.1 132.2 121.8 38.0Preston Reservoir Evaporation ac-ft 0.0 -0.2 -0.1 -0.2 -0.5 -1.1 -3.5 -6.8 -9.0 -10.4 -8.5 -5.6 -46.1 -2.7 -1.0 -0.5 -0.6 -0.9 -2.0 -3.7 -6.2 -8.1 -9.3 -7.5 -2.4 -44.9 Preston Reservoir Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Total Beginning Water Storage ac-ft 27.5 95.8 147.2 227.9 395.1 465.7 524.8 568.0 503.6 405.5 284.2 184.6 130.1 139.1 199.0 264.1 332.0 389.0 445.0 447.2 379.0 273.9 159.1 65.5Total Reservoir Evaporation ac-ft -1.8 -1.2 -0.7 -0.9 -2.0 -4.4 -11.5 -20.3 -26.1 -28.0 -19.4 -10.1 -126.5 -4.9 -1.9 -1.2 -1.4 -2.5 -5.7 -10.9 -18.5 -22.8 -22.5 -13.7 -6.2 -112.3 Total Reservoir Percolation ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

LAND APPLICATION DISPOSAL DEMANDS
Bowers' Ranch ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.02016/2017 WY Bower's Ranch ac-ft -7.7 0 0 0 0 0 0 0 -24.6 -26.7 -26.7 -26.7 -112.4Hoskins' Ranch ac-ft -3.3 0.0 0.0 0.0 0.0 0.0 -2.3 -19.4 -24.7 -26.0 -23.5 -16.4 -115.5 -1.8 0.0 0.0 0.0 0.0 0.0 -3.2 -16.4 -22.8 -24.9 -23.1 -14.6 -106.72016/2017 WY Hoskin's Ranch ac-ft 0 0 0 0 0 0 0 -8.3 -27 -32.8 -26.4 -36.5 -131.0COWRF and Castle Oaks Golf Course ac-ft -11.3 0.0 0.0 0.0 0.0 0.0 -11.9 -61.7 -89.4 -99.9 -89.4 -59.9 -423.4 -27.3 0.0 0.0 0.0 0.0 0.0 -35.3 -70.1 -92.4 -100.9 -91.1 -64.6 -481.7

UNMET IRRIGATION DEMANDS
Bower's Ranch Unmet Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Hoskin's Ranch Unmet Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 COGC Unmet Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 13.0Total Unmet Irrigation Demands ac-ft 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 13.0 13.0

MONTHLY STORAGE BALANCE
Total Inflows (excluding Unmet Irrigation Demands) ac-ft 84.5 52.6 81.4 168.2 72.6 63.5 68.8 37.0 42.2 32.6 32.8 31.8 768.0 43.0 61.8 66.3 69.4 59.5 61.6 51.7 36.7 32.9 33.5 34.3 34.5 585.1 Total Inflows (including Unmet Irrigation Demands) ac-ft 84.5 52.6 81.4 168.2 72.6 63.5 68.8 37.0 42.2 32.6 32.8 31.8 768.0 43.0 61.8 66.3 69.4 59.5 61.6 51.7 36.7 32.9 33.5 34.3 47.5 598.1 Total Outflows ac-ft -16.3 -1.2 -0.7 -0.9 -2.0 -4.4 -25.7 -101.4 -140.3 -153.9 -132.3 -86.4 -665.4 -34.0 -1.9 -1.2 -1.4 -2.5 -5.7 -49.4 -105.0 -138.0 -148.3 -127.9 -85.5 -700.7Beginning Storage Volume ac-ft 27.5 95.8 147.2 227.9 395.1 465.7 524.8 568.0 503.6 405.5 284.2 184.6 130.1 139.1 199.0 264.1 332.0 389.0 445.0 447.2 379.0 273.9 159.1 65.5Change in Water Volume ac-ft 68.3 51.5 80.6 167.2 70.6 59.1 43.2 -64.4 -98.1 -121.3 -99.6 -54.6 9.1 59.9 65.1 68.0 57.0 55.9 2.3 -68.3 -105.1 -114.8 -93.6 -38.0Final Storage Volume ac-ft 95.8 147.2 227.9 395.1 465.7 524.8 568.0 503.6 405.5 284.2 184.6 130.1 139.1 199.0 264.1 332.0 389.0 445.0 447.2 379.0 273.9 159.1 65.5 27.5 Maximum Seasonal Storage Used (ac-ft) 568.0 185.1 Mgal Maximum Seasonal Storage Used (ac-ft) 447.2 145.7 Mgal Henderson Unutilized Capacity (ac-ft) 0.0 0.0 Mgal Henderson Unutilized Capacity (ac-ft) 92.4 30.1 Mgal Preston Unutilized Capacity (ac-ft) 59.8 19.5 Mgal Preston Unutilized Capacity (ac-ft) 88.2 28.7 Mgal

WASTEWATER INFLUENT FLOW MAX STORAGE CAPACITIES OTHER INPUTS 100-YEAR ANNUAL PRECIPITATION RETURN PERIOD AVERAGE ANNUAL PRECIPITATION RETURN PERIOD

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1001 Galaxy Way
Suite 310
Concord CA 94520
925.949.5800 phone
925.949.5845 fax
westyost.com

TECHNICAL MEMORANDUM
DATE: February 26, 2024 Project No.: 988-50-24-10
SENT VIA: EMAIL
TO: George Lee, City Manager, City of Ione
CC: Justin Granados, WaterStone Services
FROM: Kathryn Gies, PE, RCE #65022
Allie Ahern, EIT
REVIEWED BY: Charles Hardy, PE, RCE #71015
SUBJECT: Updated Water Balance for City of Ione Wastewater Treatment Facility, Waste Discharger Requirements Order R5-2013-0022-001
This technical memorandum (TM) provides information and supporting documentation related to an updated water balance for the City of Ione (City) Wastewater Treatment Facility (WWTF). The following topics are addressed:
• Background Information
• Existing Facilities
• Historical Influent Flows
• Climate Data
• Current (2024) Influent Flows
• Projected 2030 Influent Flows
• Estimated Capacity of Existing Discharge Areas
• Operational Assumptions
• Water Balance Results

BACKGROUND INFORMATION
Waste Discharge Requirements
The City and the Jackson Rancheria Development Corporation (Jackson Rancheria) are the two entities permitted under Central Valley Regional Water Quality Control Board (Regional Board) Waste Discharge Requirements (WDRs) Order R5-2013-0022-001 and the associated Revised Monitoring and Reporting Program R5-2013-0022 REV1 (MRP) (Regional Board, 2014b) for the treatment of domestic wastewater at the WWTF and disposal and reuse of the secondary effluent. The WDRs were initially adopted on April 11, 2013, and revised December 5, 2014 (Regional Board, 2014c). 395
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The WDRs present the following information related to the capacity of the WWTF and disposal system:
• The allowable influent average dry weather flow (ADWF)1to the WWTF is limited to

0.50 million gallons per day (mgd) based on the water balances that were included in the City’s 2012 Report of Waste Discharge (ROWD) (GHD Inc., 2012a). • The allowable influent ADWF to the WWTF can increase to 0.52 mgd following Executive Officer approval of a 2020 Capacity Expansion Completion Report. The WDRs were modified in 2014 to make this provision performance-based because of changes in City operations that occurred in 2013 that effectively increased the available disposal capacity provided by the percolation basins. However, the 0.52 mgd limit was not modified. The understanding at the time was the capacity limit would be modified with the submission of the 2020 Capacity Expansion Completion Report.
• WDRs Finding 29 states: “The City states that the current treatment capacity is 0.55 mgd.” Cease and Desist Order
On December 5, 2014, the Regional Bord adopted Cease and Desist Order 2014-0157 (CDO) (Regional Board, 2014a) that addressed the City’s inability to comply with the following requirements of the WDRs:
• Prohibition A.1: Discharge of wastes to surface waters or surface water drainage courses is prohibited. (Only as this provision relates to the discharge of degraded groundwater into Sutter Creek).
• Groundwater Limitation D.2: Release of waste constituents from any portion of the WWTF shall not cause groundwater to contain constituents in concentrations that exceed either the Primary or Secondary Maximum Contaminant Levels established therein. • Discharge Specification E.1: No waste constituent shall be released, discharged, or placed where it will be released or discharged, in a concentration or in a mass that causes violation of the Groundwater Limitations of [the WDRs].
• Discharge Specification E.3: The discharge shall remain within the permitted waste treatment/containment structures and land application areas (LAAs) at all times.

The CDO specifically requires a series of actions to be completed by the City to address the issues identified above. These actions are as follows:
• Construct facility improvements that will effectively stop the mechanisms that result in the mobilization and discharge of iron and manganese in violation of the Groundwater Limitations in the WDRs;
• Effectively stop any indirect discharge (seepage) of polluted groundwater to Sutter Creek; and • Bring the facility into compliance with the WDRs.
1 ADWF is defined in the WDRs as the total flow for the months of July through September, inclusive, divided by 92 days.
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Compliance with the first requirement was to be demonstrated through achievement of specific groundwater numeric targets defined in the CDO. The CDO also requires that all ponds be lined or permanently closed if the specified groundwater numeric targets for iron and manganese defined in the CDO are not met by their compliance dates.
13267 Order Requirements
On August 14, 2024, the Regional Board issued a 13267 Order letter to the two WDRs permittees that requires submittal of an updated water balance for the WWTF to the Regional Board by December 13, 2024.

The letter specifies the following three items that should be included in the water balance:
• The forecasted influent flows and proposed flows over the next 5 years based on population growth. Estimates must be supported by City planning documents. • Any changes to collection system, treatment plant, and disposal features or their operation planned in the next 5 years.
• If the facility does not have sufficient capacity to treat and dispose of all wastewater onsite, the submittal must include the volume of excess effluent that would need to be disposed of each year to ensure all wastewater is treated and disposed of properly without causing or threatening to cause a violation of the permit or a condition of pollution.

The 13267 Order also states that the water balance must be in compliance with the requirements and guidance of the Regional Board’s guidance document Requirements for Water Balance Update and Calibration.

In addition to the above requirements, Regional Board staff issued an email to the City that stated that the Regional Board cannot consider a water balance complete if it represents operation of a facility that causes violation of a WDRs and/or an enforcement order, with the following examples of reasons the Regional Board would consider a water balance incomplete:

The provided influent flow rate is higher than the treatment capacity, which could cause effluent limit exceedances.

The provided rate of treated wastewater being applied to a LAA is too high and threatens to impact groundwater or violate conditions of the WDRs such as runoff or saturated conditions.

The inclusion of disposal capacity via percolation ponds which are required to be lined or closed by an enforcement order.

The acceptance of a waste stream not described in the WDRs.

The operation of ponds or reservoirs that would exceed freeboard requirements of the WDRs.

Of the above-listed examples, Numbers 1 and 3 could pertain to the WWTF. Therefore, both topics are addressed herein.
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Review Of Site-Specific Water Balance
On February 3, 2025, Regional Board staff issued a letter titled Review of Site Specific Water Balance that identified data gaps and deficiencies that must be addressed. The following specific changes were required:
• The WDRs state that the total disposal capacity of the facility is 0.75 MGD, with the caveat that: “The water balances are based on the assumption of year-round cropping of all available LAAs. Therefore, this Order requires year round cropping of all LAAs and allows year-round irrigation with recycled effluent to meet crop water needs.” The Town Field, a 67 acre land application area (LAA) that provides roughly 85% of the permitted disposal capacity, is leased to and managed by a farmer who does not crop year round. Standing water after rain events percolates slowly due to higher groundwater leaving the LAA saturated for long periods of time. Consequently, irrigation and cropping during the wet season is highly variable. Board staff’s understanding is that the City has no control of how the LAA is managed.

In addition, since the WDRs were adopted the City modified the treatment train by lining Ponds 1-5. Ponds 1-4 were unlined treatment ponds, and pond 5 was a percolation pond.

Lining Ponds 1-5 decreased the disposal capacity due to the loss of percolation.

The water balance includes scenarios where Ponds 6 and/or 7 are used for percolation. This is not consistent with the requirements of the Ione WWTF WDRs or Cease and Desist Order (CDO) R5-2014-0157, which requires the lining or closure of the ponds. The effluent disposal capacity and flow limit in the WDRs have not been modified to reflect these changes.

Therefore the 0.75 MGD effluent disposal capacity is an overestimation and should not be used. The Report shall be updated to reflect the calculated current disposal capacity conditions within the requirements of the CDO and WDRs, and include supporting technical analysis to support that value.
• Rainfall data for a 1-100-year wet season is based on 2016/2017. Although the total rainfall is higher than 2020-2024 the distribution of storms is very different. In 2017 the rain was much heavier in January/February, but other months had more rain during 2020-2024 than they did in 2017. It may be more representative to distribute the total flow more evenly over the wet season of the 1-100 model year. However, as this is occurring in the midst of the wet season when storage capacity is high and irrigation potential is low the effect may be minimal. The Discharger shall examine the sensitivity of the water balance to changes in monthly rainfall and include narrative analysis of the findings. If needed a factor of safety should be integrated into the water balance to accommodate fluctuations in estimated monthly rainfall values.
• Tailwater flows from the Town Field are estimated as no flow data is available. However, for months when greater than eight (8) inches of precipitation are projected the submitted water balance caps the amount of tailwater received from the Town Field at eight (8) inches.

More information shall be submitted to support this restriction [ i.e. the water balance caps the amount of tailwater received from the Town Field as the runoff calculated form eight (8) inches of rainfall], or the water balance shall be revised to not include a cap on precipitation values used to estimate tailwater flows.
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Sutter Creek City CouncilMarch 17, 2025

Sutter Creek City Council
March 17, 2025