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Wastewater Treatment Facility and Effluent Disposal Improvements

Table of Contents

1.0 PROJECT DESCRIPTION.....................................................................................................11.1 PROJECT OBJECTIVE..........................................................................................................11.2 MEANS OF COMPLIANCE....................................................................................................21.3 THE PROPOSED PROJECT AND ALTERNATIVE PROJECTS...........................................3

1.3.1 Proposed Project: Disposal of WWTF Effluent by Application to Pasture Land and Discharge to Jackson Creek....................................................................................4

1.3.2 Alternative A: Continue Year-Round Effluent Discharge to Jackson Creek without Providing Additional Dilution to the Effluent Discharge.........................................13

1.3.3 Alternative B: Proposed Project without the 5 Percent Effluent Limit in Lake Amador or Daily Dilution Requirements in Jackson Creek....................................16

1.3.4 Alternative C: Seasonal Equalization of Natural Jackson Creek Flows to Allow Continued Year-Round Discharge of Effluent to Jackson Creek..........................19

1.3.5 Other Alternatives Considered but Dismissed by the City.....................................24

FIGURES:

Figure 1 City of Jackson Wastewater Treatment Facility Improvements Proposed Project – WWTF Physical Improvements..................................................................................11

Figure 2 City of Jackson Wastewater Treatment Facility Improvements Proposed Project – Offsite Physical Improvements..................................................................................12

Figure 3 City of Jackson Wastewater Treatment Facility Improvements Alternative A – WWTF Physical Improvements..............................................................................................15

Figure 4 City of Jackson Wastewater Treatment Facility Improvements Alternative B – WWTF Physical Improvements..............................................................................................18

Figure 5 City of Jackson Wastewater Treatment Facility Improvements Alternative C – WWTF Physical Improvements..............................................................................................22

Figure 6 City of Jackson Wastewater Treatment Facility Improvements Alternative C – Offsite Physical Improvements..............................................................................................23

TABLES:

Table 1 Proposed Project – Under Permitted Design Effluent Flow Conditions – Estimated Effluent Storage and Land Application Area Needs as a Function of Rainfall and Soil Percolation Rates.......................................................................................................26

Table 2 Proposed Project – Under Current Effluent Flow Conditions (Current Community Development) -Estimated Effluent Storage and Land Application Area Needs as a Function of Rainfall and Soil Percolation Rates.........................................................27

Table 3 Proposed Project – Regulatory Concerns and Means of Compliance.......................28Table 3 Proposed Project – Regulatory Concerns and Means of Compliance (continued)....29Table 4 Proposed Project – Physical Plant Improvements.....................................................30Table 4 Proposed Project – Physical Plant Improvements (continued)..................................31

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Table 5 Proposed Project – Estimates of Possible Changes in Water Resource Quantity and Quality........................................................................................................................32

Table 5 Proposed Project – Estimates of Possible Changes in Water Resource Quantity and Quality (continued).....................................................................................................33

Table 5 Proposed Project – Estimates of Possible Changes in Water Resource Quantity and Quality (continued).....................................................................................................34

Table 6 Alternative A – Regulatory Concerns and Means of Compliance..............................35Table 6 Alternative A – Regulatory Concerns and Means of Compliance (continued)...........36Table 7 Alternative A – Physical Plant Improvements............................................................37Table 8 Alternative A – Estimates of Possible Changes in Water Resource Quantity and

Quality........................................................................................................................38Table 9 Alternative B – Estimated Effluent Land and Storage Application Needs for Worst

Case Conditions.........................................................................................................39Table 10 Alternative B – Regulatory Concerns and Means of Compliance..............................40Table 10 Alternative B – Regulatory Concerns and Means of Compliance (continued)...........41Table 11 Alternative B – Physical Plant Improvements............................................................41Table 12 Alternative B – Estimates of Possible Changes in Water Resource Quantity and

Quality........................................................................................................................42Table 12 Alternative B – Estimates of Possible Changes in Water Resource Quantity and

Quality (continued).....................................................................................................43Table 12 Alternative B – Estimates of Possible Changes in Water Resource Quantity and

Quality (continued).....................................................................................................44Table 13 Alternative C – Regulatory Concerns and Means of Compliance..............................45Table 14 Alternative C – Physical Plant Improvements............................................................46Table 15 Alternative C – Estimates of Possible Changes in Water Resource Quantity and

Quality........................................................................................................................47

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1.0 Project Description

Need : The need for the proposed wastewater treatment and disposal project was created primarily by Waste Discharge Requirements adopted by the California Regional Water Quality Control Board, Central Valley Region, (aka, Regional Water Board) in 2007 in Order No. R5-2007-0133 (hereinafter, 2007 Order). These requirements affect 1) the quantity of City effluent that can be discharged to Jackson Creek (relative to the accumulated percentage of effluent in Lake Amador, a downstream reservoir serving as a source of water for a public water supply), and 2) the quality of City effluent that can be discharged to Jackson Creek (based on what was known about Jackson Creek and the effluent discharge in 2007). Specifics of these requirements include:

By 25 October 2012, the City is prohibited from discharging effluent to Jackson Creek in amounts that cause Lake Amador to contain more than five percent effluent on a volume basis. The basis for compliance determination is limiting the volume of effluent discharged to Jackson Creek in any given month such that the resultant percent effluent in Lake Amador does not exceed five percent.

There are new effluent limitations for copper, zinc, dichlorobromomethane (DCBM), and ammonia.

Additionally, historical compliance problems with effluent limitations on turbidity, coliform, and nitrate need to be addressed as part of this compliance project along with an assessment of whether the effluent discharge is in compliance with narrative policy objectives of the Regional Water Board as stated in its Basin Plan. The 2007 Order will be revised in 2012, and this “New Order” is expected to contain revisions to the 2007 Order based on the results of on-going studies of the feasibility of various wastewater treatment and disposal alternatives.

1.1 PROJECT OBJECTIVE

City objectives in proposing a wastewater treatment and disposal project include the following:

1. The over-riding objective is to provide an improved wastewater treatment facility (hereinafter WWTF, including wastewater treatment processes and effluent disposal methods) to meet the existing needs of the City of Jackson, and to the extent reasonable, the future needs of the City of Jackson within the limits of the permitted capacity of the existing WWTF.

2. To achieve this objective requires the planning, design, construction, and operation/maintenance of various WWTF improvements that are cost-effective and minimize rate increases, while complying with the intent of the 2007 Order and anticipated requirements in the New Order.

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3. To improve the City’s wastewater effluent quality and disposal method in a manner that protects the existing beneficial uses of Jackson Creek and Lake Amador to the maximum extent reasonable.

In the City’s efforts to achieve these objectives, public involvement is an important aspect of the overall improvements plan so that City residents and businesses know what the City is doing with their wastewater, why, and how the City intends to 1) protect public health and the environment, 2) comply with pertinent laws and regulations, and 3) thereby protect the value of properties served by the wastewater utility.

1.2 MEANS OF COMPLIANCE

Possible means to achieve compliance with 2007 Order requirements and realistic modifications thereto in the New Order include:

1. To comply with effluent dilution requirements in Lake Amador (a 2007 Order requirement) and to avoid effluent-dominated conditions in Jackson Creek (a Basin Plan objective) requires:

a. Reduced dry season effluent discharges to Jackson Creek; and/or,

b. Increased dry season flows in Jackson Creek to provide dilution to any effluent discharged during dry seasons.

2. To maximize compliance with Basin Plan reclamation, land disposal, and surface water discharge policies requires reduced effluent discharges to Jackson Creek, particularly during dry seasons, to the extent reasonable.

3. To maximize compliance with existing and anticipated new effluent limitations requires:

a. Improved source control (i.e., increased regulation and policing of wastes generated by homes and businesses); and/or,

b. Improved wastewater treatment; and/or,

c. Reduced dry season effluent discharges to Jackson Creek so as to receive dilution credits for what effluent is discharged to Jackson Creek; and/or,

d. Increased dry season creek flows to provide needed dilution credits to current dry season effluent discharges to the creek; and/or,

e. Water effect ratio and/or translator studies for copper and/or zinc to determine stream-specific water quality objectives for these metals in Jackson Creek.

With there being no known source of water from outside of the Jackson Creek watershed to add water to Jackson Creek in droughts, realistic means of compliance include:

1. Reducing or eliminating dry season effluent discharges to Jackson Creek. This means of compliance requires a) approval of the California Department of Water Resources, Division of Water Rights (hereinafter, Division), and b) a means to reclaim or dispose of the effluent no longer discharged to Jackson Creek.

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2. Diverting higher, storm-related flows from Jackson Creek to a reservoir so that this water can be released back to the creek during following dry seasons to a) maintain Jackson Creek dry season flows (e.g., to meet minimum creek flow requirements if required by the Division), and/or b) provide reliable dilution credits for continued effluent discharges of some magnitude to Jackson Creek during dry seasons.

3. Improving wastewater treatment.

1.3 THE PROPOSED PROJECT AND ALTERNATIVE PROJECTS

Based on the foregoing project objectives and means of compliance, the City has considered many possible compliance projects, has selected a Proposed Project, and wishes to consider three alternative projects via an inclusive public involvement process. The Proposed Project and the three selected alternatives are introduced below, and discussed in greater detail in the following sections. Other projects considered and rejected are listed at the end of this section.

Proposed Project. The key element of the Proposed Project is that it reduces (to the point of stopping, when needed) effluent discharges to Jackson Creek during dry seasons when creek flows can be very low to zero. Reducing the current effluent discharges to Jackson Creek requires approval from the Division. Effluent no longer discharged to the creek is either applied to grazing land or stored in a reservoir for subsequent disposal to pasture land or Jackson Creek. The proposed effluent storage reservoir(s) and effluent application lands will be located on the Busi Ranch, which is situated less than a mile from the WWTF. Effluent will continue to be discharged to Jackson Creek to the extent reasonable. The Proposed Project also improves the existing wastewater treatment process in various ways.

The net effect of the Proposed Project is a substantial reduction in the amount of effluent discharged to Jackson Creek, particularly during dry seasons. This reduction results in:

Compliance with the 2007 Order’s five percent effluent limit in Lake Amador.

Avoidance of effluent dominated conditions in Jackson Creek per Basin Plan policies, which thereby opens the possibility for the City to receive effluent dilution credits in Jackson Creek, if needed after proposed treatment process improvements.

Increased effluent reclamation and decreased effluent discharges to surface waters, particularly in dry seasons, per Basin Plan policies.

Jackson Creek (already an ephemeral stream upstream of the WWTF) becoming an ephemeral stream downstream from the WWTF. Currently, Jackson Creek downstream from the WWTF is a perennial stream solely because of the City’s year-round effluent discharge to the creek.

Alternative A. Alternative A is a form of “No Project” alternative in so far as it essentially maintains status quo hydraulic conditions in the area, i.e., the City continues to discharge effluent to Jackson Creek, year-round, regardless of creek flows and regardless of effluent percentages in Lake Amador. Alternative A appears to be the City’s default project if Department of Fish and Game or others’ concerns result in the Division not approving the City’s proposal under the Proposed Project to reduce (including to the point of stopping) effluent

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discharges to Jackson Creek in dry seasons. Though Alternative A is a form of “No Project” alternative, it is not a “do nothing” alternative. With Alternative A, the City undertakes considerable improvements to the wastewater treatment process and may conduct special studies to provide some mitigation to the impacts resulting from the City 1) not complying with the five percent effluent limit in Lake Amador, and 2) receiving no effluent dilution credits in Jackson Creek.

Alternative A does not require approval from the Division.

Alternative B. Alternative B 1) is like the Proposed Project in that it applies dry season effluent to Busi Ranch, and 2) is like Alternative A in that it discharges effluent to Jackson Creek, as needed, to minimize effluent storage requirements at Busi Ranch. Under Alternative B, Lake Amador may contain more than five percent effluent under protracted, severe droughts; and Jackson Creek will be effluent dominated (i.e., contain more than 50 percent effluent) at times.

As with the Proposed Project, Alternative B requires approval from the Division.

Alternative C. Alternative C has been proposed by members of the general public and involves 1) continued year-round discharge of effluent to Jackson Creek (like Alternative A), but 2) proposes to store some of the wet season Jackson Creek higher flows and local runoff in a reservoir to be located near the WWTF. The stored creek water and runoff are to be released back to Jackson Creek during following dry seasons to dilute the effluent discharge to the extent needed. Alternative C has been proposed as a possible means to 1) comply with the five percent effluent limit, 2) provide needed dilution credits for effluent discharged to Jackson Creek year-round (and thus avoid the added treatment process costs potentially associated with Alternative A), 3) avoid effluent dominated conditions in the creek without drying up the creek on occasion (as would occur with the Proposed Project or Alternative B), and 4) avoid the expense of effluent reclamation and land disposal facilities needed for the Proposed Project or Alternative B. Alternative C requires construction of a storage reservoir and conveyances (including a pump station) between Jackson Creek, the WWTF, and the reservoir.

Because Alternative C involves diverting water from Jackson Creek, it requires approval from the Division.

1.3.1 Proposed Project: Disposal of WWTF Effluent by Application to Pasture Land and Discharge to Jackson Creek

With the Proposed Project, City effluent will be reused and/or disposed of, to the extent reasonable, on grazing land (Busi Ranch) near the WWTF. Effluent will continue to be discharged to Jackson Creek to the extent that 1) it cannot be disposed on land reasonably, 2) Jackson Creek can assimilate the effluent without exceeding the five percent limit in Lake Amador, 3) effluent dominated conditions in Jackson Creek do not occur, and 4) exceedances of California Toxics Rule (CTR) and related limitations in Jackson Creek do not occur. Effluent that cannot be discharged to land or the creek will be stored at Busi Ranch for subsequent disposal via land application and/or retreatment at the WWTF for discharge to Jackson Creek.

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Effluent discharges to land will be controlled to the extent that 1) there is effluent in need of disposal, and 2) operating the effluent application system will not cause:

Effluent runoff.

Vegetation damage.

Soil damage.

Significant hindrance of the ranching operation.

Degradation of groundwater quality not acceptable to the Regional Water Board.

Excessive surfacing of shallow groundwater at some distant downslope location. It is worth noting that effluent infiltrated into soil eventually surfaces some place, in some manner. The regulatory issues with such surfacings are proximity, volumes, and resulting impacts on the environment.

Effluent discharges to Jackson Creek will be controlled to prevent the percentage of effluent in Lake Amador from exceeding five percent of lake volume using a very simplistic, but reliable and conservative method. This method consists of limiting annual effluent creek discharges to no more than five percent of the creek flow passing the WWTF plus 42 percent to account for runoff to Lake Amador from the lower Jackson Creek watershed (which has 68% of the land area of the upper watershed, but with lower rainfall and runoff coefficients). The annual accounting is from June 1 through the following May 31 (i.e., June 1 through May 31 is the “Disposal Year” for the Proposed Project). The Disposal Year was developed based on the Proposed Project stopping effluent discharge to Jackson Creek every June 1 through September 30, which comprises the main land irrigation season. The Disposal Year is very similar to the “Water Year” in California (October through September) because the four-month offset between the two (from June 1 to October 1) is a “dry season” when little rain occurs. The main difference is that the Disposal Year includes the Jackson Creek receding hydrograph resulting from the previous Disposal Year’s rainfall. In back-to-back droughts such as occurred in 2007-2009, this difference is not material.

This Disposal Year approach to regulating the five percent effluent limit in Lake Amador is simple, conservative, enforceable, and does not rely on the uncontrollable and unreliable variable of the amount of residual lake effluent assimilative capacity being available from Disposal Year to Disposal Year in protracted droughts such as 1975-1977, or 2007-2009.

Effluent discharges to Jackson Creek will also be controlled on a daily basis 1) to prevent the creek from containing more than 50 percent effluent, and 2) to comply with all effluent dilution requirements and dilution credits assigned to the City as the basis for receiving revised, dilution-based, effluent limitations in the upcoming New Order. In other words, water quality objectives (WQOs) will not be exceeded under any foreseeable conditions, including aquatic life WQOs under drought conditions more severe than 1-in-10 years when exceedances are permitted under the State Implementation Policy (SIP) per SIP Section 1.4.2.1, specifically Table 3, therein, which specifies the basis for developing effluent limitations for aquatic life WQOs when effluent dilution is involved at 1-in-10 year drought receiving water flow rates.

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The Proposed Project applies effluent to a large parcel of private property (Busi Ranch) whose owner has expressed willingness to enter into a long-term contract with the City to accept effluent application on his land. The Proposed Project takes advantage of the fact that in wet years Jackson Creek and Lake Amador contain greater amounts of dilution water allowing increased effluent discharges when the ability of land to dispose of effluent is reduced. Conversely, in dry years when stream and lake effluent assimilative capacities are reduced, the ability of the land to dispose of effluent is increased. In a severe drought such as 1975-1977, it is estimated that sustained Jackson Creek flows will be essentially zero, such that all effluent is planned to be applied to land.

Based on these principles, an effluent disposal water balance model was prepared for the Proposed Project based on the following input variables:

Design ADWF = 0.71 Mgal/d

Current ADWF = 0.47 Mgal/d (the approximate ADWF for summer 2007, at the beginning of the 2007-2009 drought), which is assumed to represent conditions with limited water conservation by City residents and businesses.

15 percent reduction in effluent flows in “somewhat dry” years to 1-in-10 year drought conditions as a result of water conservation with a proportionate reduction in I/I flows from lack of rainfall. This is what was observed in general in the recent 2007-2009 drought. If this level of water conservation does not occur, then the effluent storage and land application area needed would be approximately 20 percent greater than forecast by the water balance model.

20 percent reduction in effluent flows in critical droughts, such as 1975-1977, as a result of water conservation with essentially no I/I flow. City records on effluent flows and reductions during the 1975-1977 drought to provide some verification of this estimate are not available currently.

Annual projected rainfall amounts used in the water balance model were derived using the long-term historical precipitation data from the Camp Pardee (CPD) weather station near the bottom of the Jackson Creek watershed (1927 – present) correlated to rainfall data from other sites with shorter periods of record. The other sites include Pine Grove (PIN) weather station at the top of the Jackson Creek watershed (1987 – present) and rainfall records from the City’s WWTF (1994 – present).

Jackson Creek flows at the WWTF for “somewhat dry” and drier disposal years after completion of the Amador Water Agency (AWA) transmission pipeline project are estimated from the measured creek flows at the WWTF from June 1, 2008 through May 31, 2009, a below normal rainfall year following two dry years (2007 and 2008). Thus, using the June 2008 – May 2009 Disposal Year as the basis for extrapolating creek flows under other rainfall conditions does not include residual influences from preceding wet years. In other words, June 2008 – May 2009 appears to be a reasonable worst-case base condition from which to generate other hypothetical climatic and stream flow conditions in the post-AWA transmission pipeline project era.

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The typical annual Jackson Creek flow volume at the WWTF as a function of estimated average annual rainfall over the upper Jackson Creek watershed is estimated by the following equation developed by exponential regression of the limited data available.

y = 5.62x1.8859 This equation has an R2 value of 0.9207.

Where:

y = Estimated typical annual Jackson Creek flow at WWTF for a given amount of rainfall on the upper Jackson Creek watershed, Mgal/year

x = Estimated annual rainfall averaged over the upper Jackson Creek watershed, inches/year

R2 = Coefficient of variation for this equation relative to the available data. In essence, this coefficient indicates that about 92% (i.e., 0.92) of the variability in the available data is “explained” by the foregoing equation.

Example: In a typical rainfall year when rainfall on the upper watershed averages about 30.32 inches, the foregoing equation estimates annual creek runoff at the WWTF to be about 3,500 Mgal/yr. By way of comparison, 30.32 inches of rainfall on the 22,000 acre upper watershed represents 18,000 Mgal/yr of water. Thus, under average rainfall conditions, only about 19 percent (3,500/18,000 = 0.19) of the rainfall typically runs off past the WWTF on an annual basis. The remainder of the rainfall water is believed to be evaporated, evapotranspirated, and percolated into the soils, rocks, and mine shafts of the upper watershed.

Though this equation explains 92 percent of the variability in the available dataset, it is not the entire story from the perspectives of environmental protection and wastewater regulation. Specifically, the actual amount of rainfall runoff that will occur, and when it occurs, are a function of not only the total annual amount of rainfall, but also when it occurs and at what intensity relative to the moisture content of the soil at the time the rainfall occurs. In other words, for a given amount of annual rainfall, there are innumerable specific rainfall frequencies, durations, intensities, and soil conditions; and therefore, there are innumerable possible flow patterns and flow volumes in Jackson Creek over the course of a Disposal Year for a given amount of rainfall. As an example, the regression equation explaining 92 percent of the variability in the existing rainfall vs. runoff dataset estimates that “typically” the annual Jackson Creek flow at the WWTF in Disposal Year June 2008-May 2009 (upper watershed rainfall estimated to be 25.52 inches) would be 2529 Mgal/yr. The actual flow was measured to be 2008 Mgal/yr, roughly 80 percent of the estimated “typical” value. This lower than “typical” runoff is believed to be a result 1) the drought conditions leading up to Disposal Year June 2008-May 2009 (i.e., there was little residual water or soil moisture on the watershed from the previous year), and 2) the specific rainfall frequencies, durations, and intensities that occurred in this Disposal Year. To account for this uncertainty in actual Jackson Creek flows that would occur more frequently in droughts, the equation-derived “typical” Jackson Creek flow estimates for 10-year drought rainfall amounts and critical drought rainfall amounts

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were reduced by 20 percent. Thus, the annual flow volumes of Jackson Creek used in developing the Proposed Project are as follows:

Rainfall Condition

Estimated Average Rainfall over Upper

Watershed,inches

“Typical” Annual Jackson Creek Flow

at WWTF,Mgal/yr

Annual Jackson Creek flow at WWTF used in

Analysis,Mgal/yr

Notes Regarding Flow used in

Analysis

Above Average 40.64 6082 6082 From regression

equation

Average 30.32 3500 3500 From regression equation

Somewhat Dry

(2008-2009)25.52 2529 2008 Actual creek flow

measured

10-year Drought 19.58 1534 1227 80% of regression

equation

Critical Drought

(1976-1977)10.61 483 (a) 386 80% of regression

equation

(a) This flow is expected to occur only during and shortly after rainfall events. It is not expected that there will be any material sustained flow in Jackson Creek under critical drought conditions. Accordingly, it is assumed for the purposes of these analyses that Jackson Creek flows in critical droughts will be essentially zero, year-round, from an effluent disposal perspective.

These annual flow volumes, with the exception of critical drought flows (as noted above), are distributed into daily creek flow rates based on the creek flow pattern monitored at the WWTF in the below normal rainfall Disposal Year of June 2008-May 2009.

Effluent hardness for regulatory purposes equals 70 mg/L based on the City’s treatment process stabilization improvements.

25 percent of the creek flow is reserved as a zone of passage that cannot be used in the development of dilution credits “D” for aquatic life based water quality objectives.

The most restrictive daily “D” value for acute aquatic life criteria is 1.6 (for cyanide), which is a defacto “D” of 2.13 (1.6/(1-0.25) = 2.13) when the 25 percent zone of passage water is considered.

The most restrictive 4-day “D” value for chronic aquatic life criteria is 1.6.

The nitrate human health 30-day “D” is 0.3.

The most restrictive carcinogen long-term average “D” is 3.2.

The minimum daily “D” to avoid effluent dominated conditions is 1.0.

No effluent is discharged to Jackson Creek from June through September, regardless of creek flows or weather conditions because land application of effluent in these months is considered to be reasonable.

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No effluent is discharged to Jackson Creek when its flow is less than 0.13 Mgal/d for design 0.71 Mgal/d effluent flows, or 0.12 Mgal/d for current WWTF flows (0.47 Mgal/d without water conservation, as approximated by the 2007 ADWFs). This lower limit establishes the basis for calculating the harmonic mean flow of the creek for calculating dilution credits for carcinogens under SIP.

The overall average effluent percolation rate on the proposed effluent application lands is estimated to range from 0.035 inch/day (estimated worst case) to 0.10 inch/day (estimated best case) based on site-specific soil tests and field experiences with other effluent disposal sites in somewhat similar foothill locations. The actual overall average percolation rate for the site can be determined accurately only by long-term, extensive field trials (which include monitoring downslope areas for surfacing of effluent seepage). For the purposes of a CEQA document, the 0.035 inch/day value is used to provide a reasonable worst-case estimate of how large facilities on Busi Ranch may need to be.

Rainfall on the Busi Ranch effluent application areas is estimated to be 26.38 inches in average years, 22.20 inches in somewhat dry years (e.g., 6/08 through 5/09), 17.03 inches in a 10-year drought, and 9.23 inches in a critical drought (e.g., 6/76 through 5/77) based on Camp Pardee rainfall data adjusted to the Busi Ranch locale using the WWTF/Camp Pardee rainfall ratio of 1.27 developed from monthly rainfall data at both sites for water years 2005-2010. Rainfall patterns are derived from the 6/08 through 5/09 rainfall data set.

Results from the model for 0.71 Mgal/d design flows and 0.035 inch/day percolation rates are presented in Table 1. The greatest amount of effluent storage and effluent application land is needed under critical drought conditions when all effluent is applied to land. Under these most critical conditions, the estimated land need is 240 acres of irrigation area with additional lands for 45 Mgal of storage. For CEQA purposes, 300 acres of sprinklers and 60 Mgal of storage should be analyzed to cover unforeseen conditions that may arise during detailed design. Once the initial phase of the proposed project is constructed, extensive field trials may suggest that the long-term average soil percolation rate is greater than 0.035 inch/day, which would reduce land and storage needs. The water balance model was run using the 0.10 inch/day “best case” estimate. This resulted in a roughly 40 percent reduction in land and storage needs compared to the Table 1 estimates.

The effluent disposal water balance model was also run for a range of effluent flow conditions approximating the current level of community development, which produced an effluent ADWF of approximately 0.47 Mgal/d in Summer 2007, which is assumed to represent approximate wastewater flows without present day water conservation. Model results based on this estimate of current community ADWF are presented in Table 2. The greatest amount of effluent storage and effluent application land is, again, needed under critical drought conditions when all effluent is applied to Busi Ranch. Under these critical drought conditions, the existing population is estimated to need 30 Mgal of effluent storage and 150 acres of effluent application area assuming the “worst case” soil percolation rate of 0.035 inch/day. This low percolation rate should be used in design of the initial phase of the Proposed Project to provide reasonable assurances that the Proposed Project will function as intended under reasonable worst-case conditions. Once installed and with extensive field trials, the amount of storage and land

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actually needed for the 0.71 Mgal/d design ADWF capacity of the WWTF can be estimated more accurately. That additional capacity will be provided, as needed, by subsequent construction phases of the Proposed Project. If the initial phase land and storage facilities can also serve some to all of the capacity needs of future development based on results from the extensive field trials, then the connection fee for future development will be adjusted to reflect “pay back” for facilities built by, but not used by the existing community.

The means by which the Proposed Project achieves compliance with regulatory concerns necessitating a project are identified in Table 3. Possible changes to the WWTF potentially needed under the Proposed Project are presented in Table 4. A very preliminary layout for these possible changes in physical plant at the current WWTF site is presented in Figure 1. None of these changes is believed to pose any significant difference to the appearance, noise level, glare, vehicular traffic, or public safety risk related to the WWTF site. If the WWTF disinfection system under the Proposed Project is converted from gaseous chlorine (and gaseous sulfur dioxide) to liquid hypochlorite and de-chlorination chemicals, then the public safety risk associated with the possibility of a leak of these toxic gasses from the WWTF site would be eliminated.

The off-site facilities that make up the effluent storage and land application components of the Proposed Project include: an effluent force main from the WWTF site to Busi Ranch, plus improvements on Busi Ranch including effluent storage reservoirs, three zones of irrigation areas (upper, middle, and lower), sprinkler irrigation facilities, possible flood irrigation facilities, and site irrigation runoff containment facilities. A preliminary layout of these off-site improvements is presented in Figure 2.

Changes in water quantity and quality for Lake Amador, Jackson Creek, and Busi Ranch resulting from the Proposed Project are estimated in Table 5.

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Figure 1City of Jackson Wastewater Treatment Facility Improvements

Proposed Project – WWTF Physical Improvements

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Proposed Project – Offsite Physical Improvements

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1.3.2 Alternative A: Continue Year-Round Effluent Discharge to Jackson Creek without Providing Additional Dilution to the Effluent Discharge

With Alternative A, City effluent will continue to be discharged to Jackson Creek on a year-round basis without any means to provide a reliable minimum level of effluent dilution in Lake Amador or Jackson Creek. Alternative A is a very viable project for the City if:

Either , the Division does not approve the City’s proposal to reduce effluent discharges to Jackson Creek.

Or , the City determines that the Proposed Project is infeasible economically.

With Alternative A, Lake Amador will contain more than five percent effluent at times. The frequency and magnitude of these exceedances will increase as the community grows to its permitted WWTF capacity.

The basis for reconsidering the propriety of the five percent effluent limit in Lake Amador are as follows. The Department of Public Health’s (DPH’s) five percent effluent guidance (1987) predates 1) the California Toxics Rule (2001) controlling discharge of priority pollutants (including carcinogens) to surface waters (e.g., Jackson Creek), and 2) various amendments to the Safe Drinking Water Act requiring improved treatment of surface waters (e.g., Lake Amador) prior to use as potable water. In addition, DPH’s concerns on effluent percentages in surface waters used as potable water supplies appear to be based primarily on long-term exposure issues. Thus, relatively rare exceedances of the five percent effluent guidance under relatively rare drought conditions should not be an issue from a long-term exposure perspective as long as the long-term effluent percentage in Lake Amador does not exceed five percent. Alternative A should satisfy this criterion. The concept of the acceptability of short-term exceedances of WQOs that have been developed based on long-term exposures (e.g., for carcinogens) is approved for regulatory use in the State Implementation Policy (SIP).

Toward the end of many dry seasons, Jackson Creek base flows downstream of the WWTF will be effluent dominated. In a critical drought, it is estimated that Jackson Creek will be effluent dominated much of the year. Considering these estimates, receiving effluent dilution credits under Alternative A is thought to be unlikely. Therefore, with Alternative A, the WWTF treatment process (and source control) must be upgraded to result in compliance with WQOs without the benefit of dilution credits. This appears to be possible with the current list of effluent contaminants of regulatory concern, with the possible exception of zinc, which is added to the City’s potable water supply by AWA (an independent public agency) to reduce the corrosivity of the water supply to lead solder pipe joints, and copper water pipes.

The proposed means by which Alternative A will achieve compliance with the City’s current list of effluent constituents of concern are identified in Table 6. Possible changes to the wastewater utility physical plant potentially needed to achieve project objectives to the extent reasonable via Alternative A are presented in Table 7. A very preliminary layout for these changes in physical plant, which are limited to the current WWTF site, is presented in Figure 3. None of these facilities, with the possible exception of the potential use of ozonation treatment, is believed to pose any significant difference to the appearance, noise level, glare, vehicular traffic, or public

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safety risk related to the WWTF site. If ozonation treatment is provided, then liquid oxygen will be stored on-site, which poses the potential for an oxygen gas leak.

Converting the WWTF effluent disinfection system from chlorine to UV increases the possibility of increased pathogen concentrations in effluent discharged to Jackson Creek in the event of a treatment process upset. This is because during an upset, chlorine can still disinfect effluent of substandard quality by increasing the chlorine dose. It is difficult for UV light to disinfect substandard effluent regardless of how much the UV light “dose” (i.e., intensity) is increased. To mitigate this potential pathogen risk, it is recommended that the existing chlorine system be kept as backup to be used in the event of a treatment process upset that renders UV disinfection relatively ineffective. This mitigation measure is unnecessary if Alternative A is implemented with ozonation (see Table 6) for control of refractory organics. This is because ozone is also a very effective disinfectant that can disinfect substandard effluent by increasing the ozone dose.

Changes in water quantity and quality for Lake Amador and Jackson Creek resulting from Alternative A are estimated in Table 8. With Alternative A, no effluent is applied to Busi Ranch; therefore, there is no potential for an impact on that site.

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Alternative A – WWTF Physical Improvements

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1.3.3 Alternative B: Proposed Project without the 5 Percent Effluent Limit in Lake Amador or Daily Dilution Requirements in Jackson Creek

Alternative B is a modified form of the Proposed Project. Specifically, Alternative B is the Proposed Project but without there being 1) a five percent limit on effluent in Lake Amador or 2) any daily dilution requirements “D” on effluent discharges to Jackson Creek. In other words, the effluent must be treated to where effluent dilution is not needed (similar to Alternative A).

If the five percent effluent limit in Lake Amador is not part of the New Order and there are no daily dilution requirements on effluent discharges to Jackson Creek, then the estimated effluent storage and application land needs for Alternative B under design and current effluent flow conditions are as presented in Table 9. These land and storage needs (and associated costs) are substantially less than those presented in Tables 1 and 2 for the Proposed Project. These reduced land and storage needs come at the expense of modifying the WWTF treatment process to comply reliably with DCBM, cyanide, ammonia, nitrate, copper, and zinc WQOs to where no dilution requirements are needed. The ongoing improvements to the WWTF treatment process plus water effect ratio and translator studies for copper and zinc may make dilution requirements for these effluent constituents unnecessary. At the worst, under Alternative B, the chlorine disinfection system would need to be converted to UV disinfection (as with Alternative A), and separate denitrification basins may be needed (as with Alternative A).

Considering that Alternative B is like the Proposed Project, but may include elements of Alternative A, a legitimate question is how does Alternative B differ materially from the Proposed Project and Alternative A. These material differences are outlined below.

1. Alternative B maximizes land application of effluent in real-time, and discharges all effluent that cannot be land applied to Jackson Creek (regardless of creek flow or Lake Amador effluent percentages). This improves compliance with Basin Plan policies regarding effluent reclamation and effluent-dominated stream conditions, and reduces the overall percentage of effluent in Lake Amador materially.

2. With this approach to effluent disposal, Alternative B reduces storage costs, adds WER and translator study costs (the results of which are uncertain), and may add treatment costs, e.g., UV disinfection and/or denitrification basins and/or metals removal processes if found to be needed after the on-going treatment process improvements are completed and WER/translator studies are completed.

3. Alternative B allows effluent discharges to Jackson Creek in drought winter/spring periods when creek flows may be very low. Thus, Alternative B would maintain a reliable base winter/spring ephemeral flow in lower Jackson Creek, which would prevent drought stress on the natural ephemeral stream based ecology of lower Jackson Creek.

The means by which Alternative B achieves compliance with project objectives are identified in Table 10. Possible changes to the WWTF potentially needed under Alternative B are presented in Table 11. A very preliminary layout for these possible changes in physical plant at the current WWTF site is presented in Figure 4. None of these facilities is believed to pose any significant difference to the appearance, noise level, glare, vehicular traffic, or public safety risk related to the WWTF site. If the WWTF disinfection system under Alternative B is converted from gaseous chlorine (and gaseous sulfur dioxide) to liquid hypochlorite and de-chlorination

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chemicals or possibly UV disinfection, then the public safety risk associated with the possibility of a leak of these toxic gasses from the WWTF site would be eliminated.

The off-site facilities that make up the effluent land disposal component of Alternative B are the same as for the Proposed Project, except that the effluent application land area and storage requirements are less, as noted above.

Changes in water quantity and quality for Lake Amador, Jackson Creek, and Busi Ranch resulting from Alternative B are estimated in Table 12.

Alternative B is a potentially viable project for the City if the Division approves reducing effluent discharges to the creek, but under detailed design the City concludes that the Proposed Project is infeasible financially, and the Regional Water Board concludes that Alternative A is not acceptable to the State based on the Division’s ruling. Alternative B may also be viable for the City if the Division rejects the City’s proposal to reduce dry season effluent discharges to Jackson Creek, but allows winter Jackson Creek flows to be diverted to storage so as to provide a minimum base flow to Jackson Creek during most dry seasons. If the Division denies the City’s request to stop effluent discharges to Jackson Creek in summer (e.g., June through September) because the downstream creek will dry up, then the reservoir needed to sustain the Division’s specified base creek flow during these four months may be around 50 to 60 Mgal, not the 206 Mgal needed for Alternative C, as will be discussed. If storing up to about 60 Mgal of creek flow is feasible under Alternative B, then:

Alternative B may be acceptable to the Division because the effluent no longer discharged to Jackson Creek from June through September is replaced with stored creek water.

Alternative B may be more acceptable to the Regional Water Board than Alternative A, the default “No Project” alternative, because it reduces effluent discharges to surface waters, reduces effluent-dominated stream conditions, reduces effluent percentages in Lake Amador, and implements reclamation.

In summary, Alternative B has the potential to include elements from the Proposed Project, Alternative A, and Alternative C in a manner that may be acceptable to the various State agencies involved in the City’s regulatory process.

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18



Alternative B – WWTF Physical Improvements

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1.3.4 Alternative C: Seasonal Equalization of Natural Jackson Creek Flows to Allow Continued Year-Round Discharge of Effluent to Jackson Creek.

Alternative C is a compliance strategy proposed by members of the general public and accepted by the City Council for inclusion in the City’s CEQA document as an alternative to the Proposed Project. Stantec’s understanding of Alternative C in the context of normal water and wastewater engineering practices is presented below, in the absence of there being any other known engineering-based development, analysis, or project description of Alternative C.

Under Alternative C, the City would buy or lease land at the base of an approximately 280-acre watershed immediately upstream of the WWTF site for the purpose of constructing an up to 633 AF (206 Mgal) storage reservoir. High flows in Jackson Creek during and immediately after major rain events on the watershed would be diverted from the creek and pumped up into the reservoir. Creek water thus stored each wet season would be released back to Jackson Creek, as needed, so as to provide in real time 19 to 1 dilution of the City’s effluent discharge to the creek. This would result in 1) complying with the five percent effluent limit in Lake Amador (without reliance on any runoff from the lower Jackson Creek watershed), 2) a creek dilution credit D of up to 19 for the purposes of calculating effluent limitations (which would eliminate all need for new treatment processes at the WWTF, beyond WWTF improvements currently underway), and 3) lower Jackson Creek having substantial flow downstream of the reservoir and WWTF on a year-round basis, which may shift the aquatic ecology of lower Jackson Creek.

A 206 Mgal reservoir volume, if full, can provide 19 to 1 dilution to up to 10.8 Mgal of effluent (depending on reservoir evaporation and percolation losses once creek water diversions to the reservoir are stopped because of receding creek flows relative to effluent dilution requirements). This effluent dilution volume is in addition to any effluent assimilative capacity provided by receding Jackson Creek flows upstream of the WWTF. The 206 Mgal reservoir’s full 10.8 Mgal effluent dilution capacity would satisfy City effluent discharge needs for up to around 27 days at current effluent discharge flow rates of about 0.4 Mgal/d (which reflects water conservation by City residents) if 1) Jackson Creek was dry upstream of the WWTF, and 2) there was no residual effluent assimilative capacity in Lake Amador (as may occur in a protracted drought, the critical design condition, particularly if winter Jackson Creek flows in excess of winter effluent dilution needs are stored near the WWTF rather than allowed to flow to Lake Amador to create residual assimilative capacity there). The number of days would decrease significantly at 0.71 Mgal/d permitted flows without significant water conservation by City residents and businesses. In 2008/2009, a somewhat dry period, Lake Amador was reported to have no residual effluent assimilative capacity under the five percent effluent limit, and Jackson Creek had 29 days of zero creek flow. Thus, a 206 Mgal storage reservoir does not appear to have adequate volume to provide 19:1 dilution of current effluent flows through somewhat dry watershed conditions, based on zero flow days, let alone during the many more low creek flow days preceding Jackson Creek going dry when releases from the reservoir would be needed to maintain 19:1 dilution. It does not appear that Alternative C can function as proposed, but different plans under this alternative are possible, as discussed later.

The Alternative C dam needed to create 206 Mgal of storage is expected to be a jurisdictional dam subject to regulation by the Division of Safety of Dams due to its size and location. The geotechnical report and CEQA document for the dam and reservoir site would need to conclude that geotechnical conditions on the site are suitable for construction of a dam. The type of dam

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to be used (earthen or concrete) will need to be determined by geotechnical and dam engineering specialists. An up to 80-foot high earthen dam may occupy too much volume in the proposed reservoir to be cost effective (i.e., too much of the reservoir volume may be taken up by the mass of the earthen dam creating the reservoir behind it).

The operational strategy for Alternative C is to keep the reservoir full at all times to the extent reasonable using both runoff from the reservoir’s approximately 280-acre watershed and Jackson Creek flows (by diversion) that are in excess of the creek flows needed to meet Lake Amador effluent dilution requirements and Jackson Creek CTR (and related) effluent dilution requirements. Rainfall runoff into the reservoir will be relatively minor in dry years because of the low runoff coefficients expected under limited rainfall conditions. The bulk of the water stored in the reservoir in drier years is expected to be diverted from Jackson Creek. Based on the variations in Jackson Creek flows seen in the somewhat dry 08/09 Disposal Year, it is expected that the Jackson Creek diversion pump station will need to have a capacity of up to about 20 Mgal/d. This is because high flows in Jackson Creek in drier years occur only during and immediately after major rain storms, i.e., a lot of water must be diverted from the creek over a brief period of time.

In a protracted drought, if the reservoir becomes empty of stored water for any reason (e.g., by releases to Jackson Creek, evaporation, percolation, etc.), then the effluent will be either stored in the now dry 206 Mgal reservoir (the plan proposed for Alternative C), or discharged to Jackson Creek without the benefit of any dilution (an alternative to the original plan). If Alternative C is to include effluent storage in drier years, then approval from the Division similar to that required for the Proposed Project and Alternative B is needed because diverting the effluent from an otherwise dry Jackson Creek will materially reduce creek flows downstream from the WWTF. If effluent is to be stored in the dry storage reservoir as proposed by the Alternative C proponents, then that effluent discharged to the reservoir may have to meet the same requirements as effluent discharged to a dry Jackson Creek. This is because the proposed reservoir may be a “water of the United States” based on the legal status of the watershed being dammed to create the 206 Mgal reservoir.

The means by which Alternative C may achieve compliance with projects objectives are identified in Table 13. Possible changes to the WWTF potentially needed to achieve project objectives via Alternative C are presented in Table 14. A preliminary layout for the changes in physical plant at the current WWTF site needed with Alternative C is presented in Figure 5. None of these possible changes are believed to pose any significant difference to the appearance, noise level, glare, vehicular traffic, or public safety risk related to the WWTF site. Converting the WWTF disinfection system under Alternative C from gaseous chlorine (and gaseous sulfur dioxide) to liquid hypochlorite (and de-chlorinating chemicals) would reduce the public safety risk associated with the possibility of a leak of these toxic gasses from the WWTF site.

The off-site facilities that make up the storage reservoir component of Alternative C include: a flow diversion structure in Jackson Creek with a roughly 20 Mgal/d pump station, a force main from the pump station to the storage reservoir, the 206 Mgal storage reservoir and its up to 80-foot high dam, and ancillary facilities controlling the release of stored water back to Jackson Creek. A very preliminary layout of the off-site improvements needed is presented in Figure 6.

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Changes in water quantity and quality for Jackson Creek and Lake Amador resulting from Alternative C are estimated in Table 15 based on 1) Alternative C providing no less than 19:1 dilution of the effluent year-round, with effluent being stored in the reservoir rather than discharged to the creek in protracted droughts when the reservoir may go dry, and 2) Alternative C providing the more realistic minimum needed CTR aquatic life dilution of 2.13:1 (see Table 15) on a year-round basis through 10-year droughts per SIP guidance. With Alternative C, no effluent is applied to Busi Ranch; therefore, there is no potential for an impact.

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Alternative C – WWTF Physical Improvements

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Alternative C – Offsite Physical Improvements

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1.3.5 Other Alternatives Considered but Dismissed by the City

Other compliance projects considered by the City, but dismissed from further analysis for various reasons include:

1. Discharge dry season effluent to the Mokelumne River which had adequate effluent assimilative capacity through the 1975-77 drought. Reasons not considered further:

a. The Mokelumne River is a potable water supply for East Bay Municipal Utility District (EBMUD).

b. Requires approval from the Division of Water Rights to stop dry season effluent discharges to Jackson Creek.

c. If the Division of Water Rights approves stopping dry season effluent discharges to Jackson Creek, then the Proposed Project is more appropriate than discharging the dry season effluent to the Mokelumne River.

2. Participate with AWA in a Regional WWTF Project in Martell. Reasons not considered further:

a. A joint regional project is infeasible within the time frames involved, and within the current economy.

b. Regionalization also requires approval from the Division of Water Rights to stop dry season effluent discharges to Jackson Creek.

c. If the Division of Water Rights approves stopping dry season effluent discharges to Jackson Creek, then the Proposed Project is more implementable than a Regional WWTF within the foreseeable future.

3. Use dry season effluent on City parks, school yards, cemeteries, and landscaping in general. Reasons not considered further:

a. Larger tracts of landscaped land are needed than are available currently; thus, pasture irrigation and seasonal effluent storage (i.e., a somewhat smaller scale Proposed Project) are still needed in addition to a landscape irrigation project.

b. Requires a higher level of treatment. Specifically, disinfected tertiary effluent would be needed as described in Title 22 of the California Code of Regulations.

c. Requires approval from the Division of Water Rights to stop dry season effluent discharges to Jackson Creek.

d. If the Division of Water Rights approves stopping dry season effluent discharges to Jackson Creek, then the Proposed Project is more cost effective than reclamation on landscaping plus pasture irrigation and storage because of the higher level of treatment needed, and the more costly effluent distribution and irrigation system needed.

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4. Continue year-round effluent discharges to Jackson Creek, but provide advanced wastewater treatment as used in Southern California for indirect potable reuse of municipal effluent. Reasons not considered further:

a. Reverse osmosis and advanced oxidation treatment of municipal effluent are very costly to build and operate.

b. Reverse osmosis loses approximately 20 percent of the influent flow in the form of a brine waste stream in need of very specialized treatment and/or disposal when an ocean is not immediately available to receive brine wastes.

c. Division of Water Rights approval is needed to reduce the dry season effluent discharge by 20 percent.

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Table 1Proposed Project –Estimated Effluent Storage and Land Application Area Needs as a Function of Rainfall Under Design 0.71 Mgal/d Effluent Flow Conditions (a)

Above Average Year plus Enhanced I/I per 2010/2011 I/I Model

Above Average

YearAverage

YearSomewhat Dry

Year (15% Water Conservation)

1Q10 Dry Year (15% Water

Conservation)

Critical Drought (20% Water

Conservation) (b)

Rainfall on Upper Watershed, inches/year (c) 40.64 40.64 30.32 25.52 19.58 10.61

Rainfall at Busi Ranch, inches/year (d) 35.35 35.35 26.38 22.20 17.03 9.23

Representative Disposal Year (June to May) (e) ---- ---- ---- 2008-2009 ---- 1976-1977

Creek Flow at WWTF, Mgal/year (f) 6082 6082 3500 2008 1227 Assumed 0

Total Runoff to Lake, Mgal/year (g) 8515 8515 4900 2811 1718 Assumed 0

Average Dry Weather Effluent Flow, Mgal/d 0.71 0.71 0.71 0.60 0.60 0.57

Total Effluent Flow, Mgal/yr 324 309 309 261 261 208

Total Effluent Discharge to Creek, Mgal/yr 192 192 167 128 90 0

Effluent as a % of Total Inflow to Lake 2.2 2.2 3.3 4.4 5.0 0

Total Effluent to Busi Ranch, Mgal/yr 132 117 142 133 171 208

Overall Site Soil Perc Rate, inch/day 0.035 0.035 0.035 0.035 0.035 0.035

Effluent Storage Volume, Mgal 40 40 45 45 45 45

Effluent Application Area, acres 225 200 220 200 235 240

(a) See text for all input variables to the effluent water balance model.(b) No significant I/I in critical drought because of lack of rain.(c) Estimated average rainfall over upper watershed = rainfall at Camp Pardee weather station (CPD) x 1.46.(d) Estimated rainfall at Busi Ranch disposal area = rainfall at Camp Pardee weather station (CPD) x 1.27.(e) The Disposal Year begins June 1 of each year because this is the first day of each calendar year in which all effluent for the next four months (June through

September) will be applied to land or stored, regardless of climatic variables under the Proposed Project.(f) Projected annual creek flow based on annual rainfall and runoff relationships observed in 2003-2011.(g) Creek flow at the WWTF plus 42% to account for runoff into Lake Amador from the 15,000 acre lower Jackson Creek watershed. The upper Jackson Creek

watershed has 22,000 acres.

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Table 2Proposed Project –Estimated Effluent Storage and Land Application Area Needs as a Function of Rainfall Under Current 0.47 Mgal/d Effluent Flow Conditions (a)

Above Average Year plus Enhanced I/I per 2010/2011 I/I Model

Above Average

YearAverage

YearSomewhat Dry

Year (15% Water Conservation)


Conservation)


Conservation) (b)



Representative Disposal Year (June to May) (e) ---- ---- ---- 2008-2009 ---- 1976-1977

Creek Flow at WWTF, Mgal/year (f) 6082 6082 3500 2008 1227 Assumed 0

Total Runoff to Lake, Mgal/year (g) 8515 8515 4900 2811 1718 Assumed 0




Effluent as a % of Total Inflow to Lake 1.6 1.6 2.4 3.2 4.1 0


Overall Site Soil Perc Rate, inch/day 0.035 0.035 0.035 0.035 0.035 0.035


Effluent Application Area, acres 135 120 125 115 130 150

(a) See text for all input variables to the effluent water balance model.(b) No significant I/I in critical drought because of lack of rain.(c) Estimated average rainfall over upper watershed = rainfall at Camp Pardee weather station (CPD) x 1.46.(d) Estimated rainfall at Busi Ranch disposal area = rainfall at Camp Pardee weather station (CPD) x 1.27.(e) The Disposal Year begins June 1 of each year because this is the first day of each calendar year in which all effluent for the next four months (June through

September) will be applied to land or stored, regardless of climatic variables under the Proposed Project.(f) Projected annual creek flow based on annual rainfall and runoff relationships observed in 2003-2011.(g) Creek flow at the WWTF plus 42% to account for runoff into Lake Amador from the 15,000 acre lower Jackson Creek watershed. The upper Jackson Creek

watershed has 22,000 acres.

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Table 3Proposed Project – Regulatory Concerns and Means of Compliance

Regulatory Concern Means of Compliance

More than 5% effluent from time-to-time in a potable water supply

Reduce effluent discharges to Jackson Creek by up to 100% in dry years when compliance with the 5% effluent limit is problematic.

Nitrate and Ammonia Enhance control of dissolved oxygen concentrations in the oxidation ditches to maximize simultaneous nitrification/denitrification.

Automate addition of lime to the oxidation ditches to stabilize the process pH for optimal nitrification/denitrification.

If the foregoing does not result in compliance, then optimize oxidation ditch performance to remove ammonia to less than water quality objectives, and receive effluent dilution credits for effluent nitrate discharged to Jackson Creek.

Copper and Zinc Continue efforts with AWA to reduce the corrosiveness of the City’s water supply to copper water pipes without excessive use of zinc orthophosphate (a common potable water supply corrosion control chemical).

Receive effluent dilution credits for copper and zinc in Jackson Creek. If the foregoing does not result in compliance or it is not cost effective for the City, then conduct water

effect ratio studies and/or translator studies to determine site-specific water quality objectives for copper and zinc.

Dichlorobromomethane (DCBM) and Cyanide

Reduce use of chlorine and therefore reduce the production of these chlorination disinfection byproducts (DCBM and cyanide) by stabilizing the treatment process as described under “Nitrate and Ammonia”, improving the effluent filters (see “Coliform and Turbidity), and improving the chlorination system.

Stop effluent discharges to Jackson Creek in hot weather when chlorine disinfection byproducts are more likely to form.

Receive effluent dilution credits for DCBM and cyanide in Jackson Creek.

Coliform and Turbidity Improve the effluent filters to reduce turbidity by 1) adding more filter area, 2) updating the pre-filter coagulation system, and 3) reducing the solids load to the filters by stabilizing the treatment process (see “Nitrate and Ammonia”).

Improve the disinfection system by 1) improving the quality of effluent being disinfected via the process stabilization and filtration improvements discussed above, 2) reducing hydraulic surges in the chlorine contact basin by moving the filter backwash pumps from the chlorine contact basin, and 3) increasing the efficacy of a given chlorine dose by increasing the energy gradient in the chlorine mixer.

(continued on next page)

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Table 3Proposed Project – Regulatory Concerns and Means of Compliance (continued)

Regulatory Concern Means of ComplianceBasin Plan objective to avoid effluent dominated conditions in surface waters

Reduce effluent discharges to Jackson Creek such that the creek never contains more than 50% effluent.

Basin Plan objective to maximize reclamation and land disposal of effluent, and minimize effluent discharges to surface waters

Reclaim and land apply effluent the extent reasonable.

Division of Water Rights approval The Proposed Project requires approval from the Division of Water Rights to reduce and stop effluent discharges to Jackson Creek.

If the Division of Water Rights requires maintenance of minimum dry season flows in Jackson Creek, then a possible compliance strategy under the Proposed Project is to reduce or stop effluent discharges to Jackson Creek under low stream flow conditions and provide the minimum flow requirements of the Division of Water Rights with another source of water, such as wet season Jackson Creek excess flows stored for subsequent release during the following dry season. There does not appear to be enough wet season flow in Jackson Creek in protracted critical droughts to mitigate fully the removal of the effluent. In critical droughts more severe than 10-year droughts, full protection of aquatic life may be waived by the Regional Water Board under the State Implementation Policy (SIP). In critical droughts the Regional Water Board may also waive compliance with the 5% effluent limit in Lake Amador, and possibly other long-term exposure human health concerns. Thus, the possibility exists under the Proposed Project that effluent may not be discharged to Jackson Creek in dry seasons when a minimum base flow in the creek can be maintained by other feasible means, but when those other means fall short of desired base flows, then effluent is discharged to the creek as needed to maintain those base flows. As noted, aquatic life criteria must be met through 10-year droughts per SIP. Critical issues under this possible mitigation measure to the Proposed Project are 1) the probable range of Jackson Creek hydrographic conditions under a probable range of 10-year drought conditions, and 2) the willingness of the Regional Water Board to waive 70-year exposure human health criteria during critical droughts. When considering these issues, it is important to note that 100% current City effluent (without WWTF process improvements) generally causes no toxicity to sensitive species in acute and chronic bioassay tests. Currently, 100% effluent conditions occur in Jackson Creek in critical, hot, dry season months without those conditions causing known, atypical stress on the ecology of lower Jackson Creek.

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Table 4Proposed Project – Physical Plant Improvements

The Proposed Project may include the following physical improvements:

1. Improved dissolved oxygen control in the oxidation ditches to maximize the efficiency of the simultaneous nitrification and denitrification process. Improvements include 1) the addition of dissolved oxygen sensors in each oxidation ditch; 2) improvements to the existing aeration rotors to optimize their control and response to input, including putting variable speed drives on the motors; 3) improvements to the oxidation ditch effluent weirs to maximize control of the water level and optimize the corresponding control and response of the rotor oxygenation process; 4) installation of a Supervisory Control and Data Acquisition (SCADA) system to receive input from the oxygen sensors and a) provide that input to operators who can then manually adjust the aeration equipment, b) allow the SCADA system to automatically adjust the aeration equipment in response to programed algorithm to maintain a preset oxygen concentration in the oxidation ditch, and c) collect historical data records. Any dissolved oxygen improvements would include any and all necessary appurtenances for a whole and complete operating system, including electrical improvements, mounting and hardware equipment, site work improvements, computer hardware and software, etc.

2. Addition of lime storage and feed facilities at the headworks of the treatment plant to provide pH control through the treatment process and optimize the simultaneous nitrification and denitrification process. Improvements include chemical storage and containment facilities; mixing equipment; insulation and/or heating equipment for thermal control; chemical feed pumps and controls; piping and site improvements; electrical and instrumentation equipment; and all ancillary facilities for a whole and complete pH control facility. SCADA facilities may also be included to provide automation, alarms, historical data collection and efficient operations.

3. Addition of effluent filter capacity and filtration related improvements to improve filter performance and capacity. Improvements include the addition of new sand filters or similar filtration equipment to augment capacity; improvements to the filter coagulation chemical feed, mixing, and flocculation facilities; improvements to the backwash storage and pumping facilities; improvements to the backwash waste facilities; control and alarm improvements; electrical and instrumentation; site and piping improvements; and all ancillary facilities for a whole and complete effluent filter facility. SCADA facilities may also be included to provide automation, alarms, historical data collection and efficient operations.

4. Modifications to the chlorine disinfection system to improve the disinfection process and reduce disinfection byproducts. Modifications include changing the chlorine injection location; increasing the initial mixing energy; modifying the contact pipes to eliminate unwanted solids deposition and accumulation; removing the filter backwash pumps from the chlorine channels; providing separate backwash storage and pump facilities (thus minimizing chlorine contact flow variations and surges); replacing chlorine gas with liquid hypochlorite facilities; relocating chemical instrumentation to improve responsiveness and control; electrical and instrumentation improvements; site and piping improvements; and all ancillary facilities for a whole and complete chlorine disinfection facility. SCADA facilities may also be included to provide automation, alarms, historical data collection, and efficient operations.

5. Addition of an effluent pump station to convey effluent to an off-site storage and land disposal facility. Improvements include a new wet well and pump equipment located at the WWTF; site and piping improvements; electrical and instrumentation improvements; and all ancillary facilities for a whole and complete pumping facility. SCADA facilities may also be included to provide automation, alarms, historical data collection, and efficient operations.

6. Addition of an effluent pipeline from the new pump station to the off-site storage and land disposal facility. Improvements include incorporating the effluent pipeline into the weir structure across Jackson Creek, and placement of new pipe along a designated alignment to connect the WWTF and off-site facilities hydraulically. Flow in the pipe may be bidirectional allowing for conveyance of effluent to the off-site facilities and return of said water back to the treatment plant for possible retreatment and discharge to Jackson Creek.


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Table 4Proposed Project – Physical Plant Improvements (continued)

7. Installation of a low concrete weir in Jackson Creek. Improvements include an effluent diffuser on the weir with multiple ports to distribute effluent into the creek flow to optimize mixing and allow passage of aquatic life. The weir would be constructed to include the cross-creek effluent forcemain (to off-site storage on the Busi Ranch) and would include creek flow measurement. The weir and diffuser project element includes all necessary ancillary improvements for a whole and complete diffuser facility, including necessary site, piping, electrical, and instrumentation improvements.

8. Addition of off-site effluent storage basin(s). Improvements include one or more earthen basins to store effluent during periods when discharge and/or land application of effluent are not desirable or permitted. Improvements also include embankments; overflow structure; inlet/outlet piping; level instrumentation; booster pump stations for sprinkler applications; site and piping improvements; electrical and instrumentation improvements; miscellaneous hydraulic improvements; and all ancillary facilities for whole and complete storage basins. SCADA facilities may also be included to provide automation, alarms, historical data collection, and optimize efficiency. The basins will not be lined in the normal engineering sense. However, the basins will be over excavated and backfilled to finish grade with fine-grained soils to provide additional filtration of any water percolating from the basins.

9. Addition of spray and flood irrigation fields for land application of effluent. Improvements include distribution piping; sprinkler risers and nozzles; run-off containment ditches/berms; run-off containment basins with alarms and return pumping facilities; and run-off hydraulic structures allowing preservation of natural drainage courses during periods of non-effluent application. SCADA facilities may also be included to provide alarms and historical data collection.

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Table 5Proposed Project – Estimates of Possible Changes in Water Resource Quantity and Quality

Water Resource Estimates of Possible ChangesLake Amador Quantity: Under the Proposed Project and current flow conditions, the reduction in the annual effluent reaching Lake Amador is estimated to

be about 81 Mgal in an average year, and 135 Mgal in a critical drought as shown in Table 2. Quality: Lake Amador will contain less than 5% effluent at all times. Analytically detectable changes in lake water quality are not expected to result from the Proposed Project. In theory, the removal of more than half of the effluent from the lake in droughts will reduce lake salinity, potential pathogen risk, nutrient concentrations, refractory organic concentrations, and heavy metals concentrations.

Jackson Creek Quantity: Dry season flows in Jackson Creek downstream from the WWTF will decrease substantially in typical and drier rainfall years. Under the Proposed Project, dry season creek flows downstream from the WWTF will mirror current dry season creek flows upstream of the WWTF, which are essentially zero at times. Estimates of reductions in creek flow downstream of the WWTF are presented for the period June 2008 through May 2009 (a somewhat dry period after the AWA transmission project) a 10-year dry period, and a critical drought period (1976-77).

Year/Month

Jackson Creek Flows, Average Mgal/d

Estimated Flows Upstream of WWTF DownstreamStatus Quo2008-2009

Estimated Flows Downstream of WWTFwith the Proposed Project

2008-2009 10-year Critical 2008-2009 10-year Critical2008June 0.80 0.02 0 1.20 0.80 0.02 0July 0.19 0.00 0 0.58 0.19 0.00 0August 0.01 0.00 0 0.40 0.01 0.00 0September 0.03 0.00 0 0.43 0.03 0.00 0October 0.53 0.00 0 0.94 0.64 0.00 0November 2.20 0.93 0 2.66 2.36 1.00 0December 3.88 2.20 0 4.35 4.17 2.37 02009January 6.45 4.81 0 6.97 6.78 4.99 0February 20.86 12.91 0 21.56 21.56 13.61 0March 23.94 17.07 0 24.56 24.56 17.69 0April 4.24 2.30 0 4.69 4.69 2.73 0May 3.91 0.66 0 4.37 4.37 0.93 0Mgal/year 2008 1227 386* 2269 2102 1300 386**This annual flow is estimated to occur during and shortly after rain storms. Sustained creek flows as needed for effluent discharges are not believed to occur; thus, there is zero creek flow, as shown in the table above from an effluent discharge perspective.


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Table 5Proposed Project – Estimates of Possible Changes in Water Resource Quantity and Quality (continued)

Jackson Creek Quality: When effluent percentage in Jackson Creek is at a maximum and when Jackson Creek is at its SIP background “B” concentrations, the following impacts on the quality of Jackson Creek downstream of the WWTF are estimated to occur.

Parameter

Forecast Jackson Creek Water Quality Range: Oct through May

WQO (c)Downstream Creek

Status Quo (a)Downstream Creek with

Proposed Project (b)

Oct – May “Background” Creek Quality

Per SIP (h)

Nitrate (mg/l) (as NO3) 4.0-62 3.6-22 3.4 45

Ammonia (mg/l) (as N) <0.5-6 <0.77-2.5 0.9 2.8/8.4 (e)

Copper (µg/l) <0.5-9.7 <1.4-4.3 1.8 6.7/9.7 (f)

Zinc (µg/l) 50-121 24-47 12 86/86 (f)

Aluminum (µg/l) <50-360 <50-149 50 87/200/750 (d)

Cyanide (µg/l) <2-8.2 <1.5-3.5 1.3 5.2/22 (g)

Dichlorobromomethane (µg/l) <0.37-0.82 <0.23-0.35 <0.16 0.56

(a) Based on the creek being 100% effluent at times, currently.(b) Based on upgrades to the WWTF with a forecast of effluent quality improvements resulting from those upgrades, and a minimum of daily creek

flow: effluent discharge dilution ratio of 1.6 parts of upstream creek flow to 1 part effluent discharge (excluding 25% of the upstream creek flow to serve as a “zone of passage” for aquatic life). This results in a total overall minimum upstream creek flow to effluent discharge dilution ratio of 2.13:1.

(c) WQO = water quality objective.(d) 87µg/L = chronic aquatic life WQO (not applicable based on stream hardness), 200 µg/L = SMCL average annual WQO, 750 µg/L = acute aquatic

life WQO.(e) Chronic aquatic life WQO and acute aquatic life WQO for ammonia (salmonids absent, but early life stages being present) based on a minimum

effluent dilution of 2.13 parts creek flow to 1 part effluent discharge resulting in a maximum pH (1 day/30 day average) and maximum temperature within that period for the blend of 8.0/7.9 and 10° C, respectively.

(f) Chronic aquatic life WQO and acute aquatic life WQO for these “concave down” metals based on a minimum effluent dilution of 2.13 parts creek flow to 1 part effluent discharge resulting in a seasonal worst-case hardness for the blend of 68 mg/L.

(g) Chronic aquatic life WQO and acute aquatic life WQO for cyanide.(h) These background values “B” for these specific parameters are the same for Jackson Creek considering either year-round data (Table 15), or Oct-

May seasonal data (Table 5).


34


Table 5Proposed Project – Estimates of Possible Changes in Water Resource Quantity and Quality (continued)

Busi Ranch Groundwater

Quantity: In a typical year, roughly 142 Mgal of effluent will be pumped to Busi Ranch. Roughly 220 acres of land will be irrigated under design 0.71 Mgal/d effluent flows. Considering site soils, soil depths, land slopes, underlying bedrock, and experience on somewhat similar effluent application foothill sites (e.g., San Andreas and Tuolumne City), of these typical year quantities, roughly 74 Mgal/yr evaporates and evapotranspirates to the atmosphere and 68 Mgal/yr percolates into the soil. Of this percolate, it is estimated that the bulk will flow subsurface, down-slope in the interface zone between intact/competent bedrock and the overlying soils. Some of this subsurface flow will seep into the bedrock; some will be taken up by downslope vegetation; and some will ultimately seep into natural drainage courses downslope of the effluent application areas. Setbacks between the edges of the effluent application areas and drainage courses are proposed to mitigate any significant impact potentially associated with any such seepage.

Quality: The potential impact of effluent application to pasture land on shallow groundwater quality is best estimated by review of the impacts in similar effluent application settings in San Andreas and Tuolumne City, as presented below.

Groundwater Quality Parameter

San Andreas Shallow Groundwater Quality Tuolumne City Shallow Groundwater Quality

Upgradient of Effluent Application

Downgradient of Effluent Application



Range Median Range Median Range Average Range Average

Electrical Conductivity, µS/cm 526-626 557 426-811 561 287-527 419 398-592 489

TDS, mg/L 304-392 372 244-524 405 210-360 260 210-360 301

Nitrate (as N), mg/L 1.9-3.9 2.0 <0.05-8.4 5.2 <0.1 <0.1 <0.1 <0.1

Total Coliform, MPN/100 mL <2-13 11 <2-80 15 <2 - >1,600 269 <2 <2

pH 6.5-7.0 6.7 6.7-7.7 7.1 6.0-7.4 6.8 6.3-6.9 6.6

35


Table 6Alternative A – Regulatory Concerns and Means of Compliance



Revise current regulatory guidance to reflect that with current CTR wastewater treatment requirements and current potable water treatment requirements, the 5 percent effluent limit is no longer appropriate.

In the absence of the foregoing, have it recognized in the City’s New Order that Lake Amador containing more than 5% effluent from time-to-time is not problematic considering the 70-year continuous lifetime exposure criteria used to assess the risk of carcinogens, which is one of the criteria considered by the Department of Public Health (DPH) in its continued use of its 5 percent effluent limit guidance.

In the absence of the foregoing, install an effluent ozonation system with activated carbon filtration to reduce effluent concentrations of refractory organics of concern to DPH such as residual pharmaceuticals, residual pesticides, residual household chemicals (e.g., flame retardants), etc. Formation of bromate, a carcinogen, is a potential concern with ozonation that may need to be mitigated and the residual cancer risk disclosed. Note: bromate is regulated differently from most other carcinogens.



If the foregoing measures do not result in compliance, then add denitrification basins and associated pumps and piping to the front end of the treatment process.

Copper and Zinc Continue efforts with AWA to reduce the corrosiveness of the City’s water supply to copper water pipes without excessive use of zinc orthophosphate (the commonly used corrosion control agent).

If the foregoing does not result in compliance, then conduct water effect ratio studies and/or translator studies to determine site-specific water quality objectives for copper and zinc.

If the foregoing does not result in compliance, then add calcium to the effluent to neutralize any potential toxicity posed by copper or zinc.

Dichlorobromomethane and Cyanide Convert from chlorine disinfection to UV disinfection. Develop an emergency response plan designed to mitigate the inherent risks posed by UV

disinfection in the event of a process upset when emergency effluent storage is not provided, e.g., retain the existing chlorine disinfection system as emergency backup, or install ozonation (which is also a very effective effluent disinfectant).


36


Table 6Alternative A – Regulatory Concerns and Means of Compliance (continued)


Coliform and Turbidity Improvements to the effluent filtration system and disinfection system.

Basin Plan objective to avoid effluent dominated conditions in surface waters

None

Basin Plan objective to maximize reclamation and land disposal of effluent, and minimize effluent discharges to surface waters.

None

Division of Water Rights approval Not needed

37


Table 7Alternative A – Physical Plant Improvements

Alternative A may include the following physical improvements:

1. Improvements to the oxidation ditches are the same as with the Proposed Project. See Table 4, Item 1.

2. Improvements to pH control are the same as with the Proposed Project. See Table 4, Item 2.

3. Addition of separate denitrification facilities, if needed, to provide stable nitrification and denitrification through the treatment process to remove ammonia and nitrate from the effluent. Improvements include separate anoxic basins upstream of the oxidation ditches; mixing equipment; flow measuring and flow splitting equipment; recycle pumps and piping; electrical and instrumentation improvements; site and piping work; and all ancillary facilities to provide a complete and operating nitrification and denitrification process. SCADA facilities may also be included to provide automation, alarms, historical data collection and efficient operations.

4. Improvements to the effluent filters are the same as with the Proposed Project. See Table 4, Item 3.

5. Addition of UV disinfection to the treatment process. Improvements include UV hydraulic structures; lamp channels; motor control center building; compressors; protective canopy or building; overhead crane; electrical and instrumentation; site and piping improvements; and all ancillary facilities for a whole and complete UV disinfection facility. SCADA facilities may also be included to provide automation, alarms, historical data collection and efficient operations. The chlorine disinfection facilities may be retained for emergency use in the event of a treatment process upset that renders the UV disinfection system ineffective. Modifications to existing chlorine facilities may be as noted for the Proposed Project. See Table 4, Item 4.

6. Addition of ozonation and activated carbon filter facilities to remove refractory organics from the effluent, if needed. Improvements include liquid oxygen storage and containment facilities; ozone generation equipment; ozone contact and mixing basin; and all necessary pump, pipe and control facilities. The activated carbon filters will include the activated carbon filter vessels, mounting/foundation facilities, feed pump, backwash pump, and pipe and control facilities. Both facilities will require electrical and instrumentation improvements, site and pipe improvements and ancillary facilities for a whole, complete, and operable system. SCADA facilities may also be included to provide automation, alarms, and historical data collection for an efficient operation.

38


Table 8Alternative A – Estimates of Possible Changes in Water Resource Quantity and Quality

Water Resource Estimates of Possible ChangesLake Amador Quantity: No change from status quo. As effluent flows increase to design flows, the amount of effluent in Lake Amador will increase.

Quality: Lake Amador will continue to contain more than 5% effluent at times. The magnitude and duration of exceedances of the 5% effluent limit will increase as effluent flows increase from current values of around 0.4 Mgal/d, to permitted values of 0.71 Mgal/d. Analytically detectable changes in lake water quality are not expected. If ozone treatment and activated carbon treatment are installed, then theoretically, lake concentrations of refractory organics would decrease, and bromate (a carcinogen) concentrations could increase. With the conversion to UV disinfection, an increased effluent pathogen risk occurs whenever the treatment process is upset for any reason unless the chlorine disinfection system is operated during such upsets. Ozone treatment would also mitigate this risk.

Jackson Creek Quantity: No change from status quo.

Quality: Under most critical low creek flow conditions when the creek will be 100% effluent under Alternative A, the following changes in creek water quality are forecast.

ParameterForecast Jackson Creek Water Quality Range

WQO (a)Downstream Creek

Status QuoDownstream CreekWith Alternative A

Nitrate (mg/L) (as NO3) 4.0-62 4.0-45 (b) 45

Ammonia (mg/L) (as N) <0.5-6 <0.5-1.6 (b) 1.6/8.4 (i) (g)

Copper (µg/L) <0.5-9.7 <0.5-9.7 6.9/10 (c) (d) (g)

Zinc (µg/L) 50-121 50-121 (e) 89/89 (c) (d) (g)

Aluminum (µg/L) <50-360 <50-360 (h) 200 (f)

Cyanide (µg/L) <2-8.2 <2-5.2 (b) 5.2/22 (g)

Dichlorobromomethane (µg/L) <0.37-0.82 <0.37-0.56 (b) 0.56

(a) WQO = water quality objective.(b) Reduced from current effluent values via WWTF improvements: those currently underway, and those specific to Alternative A, if needed.(c) Based on a minimum effluent hardness of 70 mg/L and 100% effluent in the creek.(d) These WQO’s are expected to increase as a result of a Water Effect Ratio study and/or translator study as demonstrated in similar foothill settings such as Grass Valley. A

major increase is expected for copper. A lesser increase is expected for zinc.(e) Further source control and/or treatment may be necessary.(f) Secondary MCL of 200 µg/L (average annual basis) governs based on stream hardness, see Table 5.(g) Chronic aquatic life WQO and acute aquatic life WQO.(h) Average annual effluent aluminum concentration is not expected to exceed 200 µg/L.(i) Chronic aquatic life WQO and acute aquatic life WQO for ammonia (salmonids absent, but early life stages being present) based on a maximum pH (1 day/30 day average)

and maximum temperature of 8.0/8.0 and 21.5° C, respectively.

39


Table 9Alternative B – Estimated Effluent Storage and Land Application Needs for Worst Case Conditions (a)

Projected Flow Conditions 0.71 Mgal/d Design Flows 0.47 Mgal/d Current Flows

Climatic Condition and Extent of Water Conservation

Average Year


Conservation)


Conservation) (b)

Average Year


Conservation)


Conservation) (b)



Creek Flow at WWTF, Mgal/year (e) 3500 1227 Assumed 0 3500 1227 Assumed 0

Total Runoff to Lake, Mgal/year (f) 4900 1718 Assumed 0 4900 1718 Assumed 0





Overall Site Soil Perc Rate, inches/day 0.035 0.035 0.035 0.035 0.035 0.035


Effluent Application Area, acres 155 (g) 130 120 95 (g) 80 75

(a) See text for all input variables to the effluent water balance model.(b) No significant I/I in critical drought.(c) Estimated average rainfall over upper watershed = rainfall at Camp Pardee weather station (CPD) x 1.46.(d) Estimated rainfall at Busi Ranch disposal area = rainfall at Camp Pardee weather station (CPD) x 1.27.(e) Projected annual creek flow based on annual rainfall and runoff relationships observed in 2003-2011.(f) Creek flow at the WWTF plus 42% to account for runoff into Lake Amador from the 15,000 acre lower Jackson Creek watershed. The upper Jackson Creek

watershed has 22,000 acres.(g) This represents the maximum estimated land need because this acreage will absorb the entire ADWF during the dry months of the year:

June through September.

40


Table 10Alternative B – Regulatory Concerns and Means of Compliance



Reduce effluent discharges to Jackson Creek by about 30% in most dry years when compliance with the 5% effluent limit is problematic.

In critical droughts effluent discharges to Jackson Creek would occur in winter/spring to sustain seasonal base flows to provide some drought relief to the natural ecology of lower Jackson Creek which is based on ephemeral stream flows. In these atypical circumstances, Lake Amador effluent percentages may exceed 5% effluent at times depending on the multi-year duration of these atypical drought conditions. Rare exceedances of the 5% effluent guidance are not believed to be a credible health risk considering current CTR wastewater treatment requirements, current potable water treatment requirements, and the 70-year continuous exposure criteria used to assess the health risk of most carcinogens.



If the foregoing does not result in compliance, then add denitrification basins ahead of the oxidation ditches as described under Alternative A.

Copper and Zinc Continue efforts with AWA to reduce the corrosiveness of the City’s water supply to copper water pipes without excessive use of zinc orthophosphate (a common potable water supply corrosion control chemical).

If the foregoing does not result in compliance, then conduct water effect ratio studies and/or translator studies to determine site-specific water quality objectives for copper and zinc.

Dichlorobromomethane (DCBM) and Cyanide

Reduce use of chlorine, and therefore, reduce production of chlorination disinfection byproducts (DCBM and cyanide) by 1) stabilizing the treatment process (as described under “Nitrate and Ammonia”), 2) improving the effluent filters (see “Coliform and Turbidity), and 3) improving the chlorination system.

Stop effluent discharges to Jackson Creek in hot weather when chlorine disinfection byproducts are more likely to form.

If the foregoing do not result in compliance then convert the chlorine disinfection system to UV disinfection, and maintain the chlorine system as backup to the UV system for use when UV disinfection may have reduced efficacy (i.e., during major WWTF process upsets).


41


Table 10Alternative B – Regulatory Concerns and Means of Compliance (continued)


Coliform and Turbidity Improve the effluent filters to reduce turbidity by 1) adding more filter area, 2) updating the pre-filter coagulation system, and 3) reducing the solids load to the filters by stabilizing the treatment process (see “Nitrate and Ammonia”).

Improve the disinfection system by 1) improving the quality of effluent being disinfected via the process stabilization and filtration improvements discussed above, 2) reducing hydraulic surges in the chlorine contact basin by moving the filter backwash pumps from the chlorine contract basin, and 3) increasing the efficacy of a given chlorine dose by increasing the energy gradient in the chlorine mixer.


Effluent dominated stream conditions will not occur in June through September because no effluent is discharged to the creek in these months. Effluent dominated conditions may occur from time-to-time in the remainder of the year depending on rainfall and resulting creek runoff flows.

Basin Plan objective to maximize reclamation and land disposal of effluent, and minimize effluent discharges to surface waters

Maximizes effluent reclamation and land disposal to the extent reasonable.

Division of Water Rights approval Alternative B requires approval from the Division of Water Rights to stop effluent discharges to Jackson Creek in June through September. During the remainder of the year, effluent discharges will continue as occur currently.

42


Table 11Alternative B – Physical Plant Improvements

Alternative B may include the following physical improvements:


2. Improvements to pH control are the same as with the Proposed Project. See Table 4, Item 2.

3. Improvements to the filters are the same as with the Proposed Project. See Table 4, Item 3.

4. Improvements to the chlorine disinfection system are the same as with the Proposed Project. See Table 4, Item 4.

5. Conveyance facilities to Busi Ranch are essentially the same as with the Proposed Project. See Table 4, Items 5 and 6. However, a weir and diffuser in Jackson Creek are not needed. Therefore, the effluent conveyance pipe crossing of Jackson Creek will be subsurface, and not visible.

6. Busi Ranch improvements are essentially the same as with the Proposed Project (see Table 4, Items 8 and 9) except as noted that the land need and/or storage need are expected to be slightly less.

7. Addition of separate denitrification facilities as described for Alternative A, if needed. See Table 7, Item 3.

8. Addition of UV disinfection as described for Alternative A, if needed. See Table 7, Item 5.

9. Addition of an up to roughly 60 Mgal creek storage reservoir upstream of the WWTF complete with diversion structure in Jackson Creek, pump station, and conveyances as described under Alternative C, if needed. See Table 14, Item 6.

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Table 12Alternative B – Estimates of Possible Changes in Water Resource Quantity and Quality

Water Resource

Estimates of Possible Changes

Lake Amador Quantity: As noted in Table 9 for current flows, Lake Amador will receive about 45 Mgal less effluent in critical droughts. In typical years, Lake Amador is forecast to receive about 58 Mgal less effluent than occurs currently without water conservation.

Quality: Lake Amador will contain less than 5% effluent, except in drier years. Analytically detectable changes in lake water quality are not expected.

Jackson Creek Quantity: June through September flows in Jackson Creek downstream from the WWTF will decrease substantially under Alternative B. In essence, dry season flows downstream from the WWTF will mirror those stream flows upstream of the WWTF. In the remainder of the year, effluent will continue to be discharged to Jackson Creek.

Year/Month

Jackson Creek Flows, Average Mgal/d

Estimated Flows Upstream of WWTF DownstreamStatus Quo2008-2009

Estimated Flows Downstream of WWTFwith the Proposed Project

2008-2009 10-year Critical 2008-2009 10-year Critical2008June 0.80 0.02 0 1.20 0.80 0.02 0July 0.19 0.00 0 0.58 0.19 0.00 0August 0.01 0.00 0 0.40 0.01 0.00 0September 0.03 0.00 0 0.43 0.03 0.00 0October 0.53 0.00 0 0.94 0.64 0.41 0.37November 2.20 0.93 0 2.66 2.36 1.39 0.37December 3.88 2.20 0 4.35 4.17 2.67 0.372009January 6.45 4.81 0 6.97 6.78 5.33 0.37February 20.86 12.91 0 21.56 21.56 13.61 0.37March 23.94 17.07 0 24.56 24.56 17.69 0.37April 4.24 2.30 0 4.69 4.69 2.75 0.37May 3.91 0.66 0 4.37 4.37 1.12 0.37Mgal/year 2008 1227 386* 2269 2102 1351 476**This annual flow is estimated to occur during and shortly after rain storms. Sustained creek flows as needed for effluent discharges are not believed to occur; thus, there is zero creek flow, as shown in the table above from an effluent discharge perspective.

42



43


Table 12Alternative B – Estimates of Possible Changes in Water Resource Quantity and Quality (continued)

Water Resource Estimates of Possible Changes

Jackson Creek Quality: At times under Alternative B the creek will contain 100% effluent, and the following ranges in creek water quality may result, as noted in Table 8 for Alternative A.

ParameterForecast Jackson Creek Water Quality Range: Oct through May

WQO (a)Downstream Creek

Status QuoDownstream CreekWith Alternative B

Nitrate (mg/L) (as NO3) 4.0-62 4.0-45 (b) 45

Ammonia (mg/L) (as N) <0.5-6 <0.5-1.9 (b) 1.9/8.4 (i) (g)

Copper (µg/L) <0.5-9.7 <0.5-9.7 6.9/10 (c) (d) (g)

Zinc (µg/L) 50-121 50-121 (e) 89/89 (c) (d) (g)

Aluminum (µg/L) <50-360 <50-360 (h) 200 (f)

Cyanide (µg/L) <2-8.2 <2-5.2 (b) 5.2/22 (g)

Dichlorobromomethane (µg/L) <0.37-0.82 <0.37-0.56 (b) 0.56

(a) WQO = water quality objective.(b) Reduced from current effluent values via WWTF improvements: those currently underway, and those specific to Alternative A, as may be needed for Alternative B.(c) Based on a minimum effluent hardness of 70 mg/L and 100% effluent in the creek.(d) These WQO’s are expected to increase as a result of a Water Effect Ratio study and/or translator study as demonstrated in similar foothill settings such as Grass Valley. A

major increase is expected for copper. A lesser increase is expected for zinc.(e) Further source control and/or treatment may be necessary.(f) Secondary MCL of 200 µg/L (average annual basis) governs based on stream hardness, see Table 5.(g) Chronic aquatic life WQO and acute aquatic life WQO.(h) Average annual effluent aluminum concentration is not expected to exceed 200 µg/L.(i) Chronic aquatic life WQO and acute aquatic life WQO for ammonia (salmonids absent, but early life stages being present) based on a maximum pH (1 day/30 day average),

and maximum temperature of8.0/8.0 and 18° C, respectively. Note, this temperature is less than in Table 8 because under Alternative B effluent is not discharged to Jackson Creek in the hot months of the year.


44


Table 12Alternative B – Estimates of Possible Changes in Water Resource Quantity and Quality (continued)

Water Resource Estimates of Possible Changes

Busi Ranch Groundwater

Quantity: In a typical year, under design flow conditions, roughly 88 Mgal of effluent will be applied to 155 acres of lands. Considering site soils, soil depths, land slopes, underlying bedrock, and experience on somewhat similar effluent application foothill sites (e.g., San Andreas and Tuolumne City), of these typical year quantities, roughly 54 Mgal/yr evaporates and evapotranspirates to the atmosphere and 34 Mgal/yr percolates into the soil. Of this percolate, it is estimated that the bulk of this added shallow groundwater will flow subsurface, down-slope in the interface zone between intact/competent bedrock and the overlying soils. Some of this subsurface flow will seep into the bedrock; some will be taken up by downslope vegetation; and some will ultimately seep into natural drainage courses downslope of the effluent application areas. Setbacks between the edges of the effluent application areas and drainage courses are proposed to mitigate any significant impact potentially associated with any such seepage.

Quality: The potential impact of effluent application on shallow groundwater quality underlying pasture land effluent application areas is as discussed for the Proposed Project. See Table 5.

Groundwater Quality Parameter

San Andreas Shallow Groundwater Quality Tuolumne City Shallow Groundwater Quality





Range Median Range Median Range Average Range Average

Electrical Conductivity, µS/cm 526-626 557 426-811 561 287-527 419 398-592 489

TDS, mg/L 304-392 372 244-524 405 210-360 260 210-360 301

Nitrate (as N), mg/L 1.9-3.9 2.0 <0.05-8.4 5.2 <0.1 <0.1 <0.1 <0.1

Total Coliform, MPN/100 mL <2-13 11 <2-80 15 <2 - >1,600 269 <2 <2

pH 6.5-7.0 6.7 6.7-7.7 7.1 6.0-7.4 6.8 6.3-6.9 6.6

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Table 13Alternative C – Regulatory Concerns and Means of Compliance



Seasonal effluent dilution provided by storing excess wet season Jackson Creek flows for release to Jackson Creek during following dry seasons. Preliminary analyses suggest that there is insufficient wet season flow in Jackson Creek in protracted droughts to provide the needed dilution water. Thus, some relief from the 5% effluent limit in Lake Amador during droughts may be necessary as outlined under Alternative A.

Nitrate and Ammonia As with the Proposed Project, if adequate dilution of the effluent discharge through droughts can be demonstrated, otherwise, as with Alternative A.

Copper and Zinc As with the Proposed Project, if adequate dilution of the effluent discharge through droughts can be demonstrated, otherwise, as with Alternative A.

DCBM and Cyanide As with the Proposed Project, if adequate dilution of the effluent discharge through droughts can be demonstrated, otherwise , as with Alternative A.

Coliform and Turbidity As with the Proposed Project.


Alternative C proposes to provide adequate base flow to Jackson Creek on a year-round basis to avoid effluent dominated conditions. As noted above, adequate creek flow may not be available at times.

Basin Plan objective to maximize reclamation and land disposal of effluent and minimize effluent discharges to surface water

None

Division of Water Rights approval Alternative C requires approval from the Division of Water Rights to remove and store substantial amounts of wet season flow from Jackson Creek for subsequent release to Jackson Creek during following dry seasons.

If under Alternative C, effluent is to be stored in the reservoir in droughts after the reservoir is emptied of creek water, then the Division of Water Rights needs to approve diverting of this effluent discharge from the creek to the reservoir.

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Table 14Alternative C – Physical Plant Improvements

Alternative C may include the following physical improvements:


2. Improvements to pH control are the same as with the Proposed Project, See Table 4, Item 2.

3. Improvements to the effluent filters are the same as with the Proposed Project. See Table 4, Item 3.

4. Improvement to the chlorine disinfection system are the same as with the Proposed Project. See Table 4, Item 4.

5. In stream weir and diffuser improvements are the same as with the Proposed Project. See Table 4, Item 7.

6. Addition of an off-line creek water storage reservoir to impound wet weather high creek flows from Jackson Creek for dry weather release back to the creek. The releases are made to maintain necessary dilution of the effluent per the 2007 Order, to the extent reasonable. Improvements include an up to 206 Mgal reservoir to store creek water; stream diversion and return flow control facility that would both pump to the reservoir and return flow to the creek; effluent pump station at the WWTF and force main to the diversion facility; site and piping improvements; electrical and instrumentation improvements, as appropriate; overflow structures; level instrumentation; miscellaneous hydraulic improvements; and all ancillary facilities for a whole and complete storage basin. SCADA facilities may also be included to provide return flow automation, alarms, historical data collection and optimize efficiency, as appropriate.

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Table 15Alternative C – Estimates of Possible Changes in Water Resource Quantity and Quality

Lake Amador Quantity: No material change.

Quality: No material change.

Jackson Creek Quantity: No material change in annual flow quantity; however wet season flows will be reduced significantly in order to increase dry season flows significantly. Very high scour flows in Jackson Creek during the wet season are expected to continue to occur because of the finite limits on the pump station conveying water from Jackson Creek to the Alternative C creek water storage reservoir.

Quality: Alternative C as proposed was to provide reliable 19 parts creek water to 1 part effluent on a year-round basis. A forecast of creek water quality under this proposal is presented below. If Alternative C is modified to provide no less than 2.13:1 dilution, worst-case creek water quality is estimated in the table below.

Parameter

Forecast of Worst-Case Quality Range (i)

Status Quo when Creek is 100%

Effluent

Year-Round “Background” Creek

Quality per SIP (h)

Alternative C with 19:1 Dilution (a)

Alternative C with 2.13:1 Dilution (b)

Creek WQO (c) Creek WQO (c)

Nitrate (mg/l) (as NO3) 4.0-62 3.4 3.4-6.3 45 3.6-22 45

Ammonia (mg/l) (as N) <0.5-6 0.9 <0.88-1.2 2.8/8.4 (d) <0.77-2.5 2.8/8.4 (d)

Copper (µg/l) <0.5-9.7 1.8 <1.7-2.2 4.9/6.9 (e) <1.4-4.3 5.5/7.8 (f)

Zinc (µg/l) 50-121 12 14-17 63/63 (e) 24-47 71/71 (f)

Aluminum (µg/l) <50-360 50 <50-66 200 (g) <50-149 200 (g)

Cyanide (µg/l) <2-8.2 1.3 <1.3-1.6 5.2/22 <1.5-3.5 5.2/22

Dichlorobromomethane (µg/l) <0.37-0.82 <0.16 <0.17-0.19 0.56 <0.23-0.35 0.56

(a) Based on 19 parts creek flow at CTR background concentration “B” and 1 part effluent discharge at the forecast worst-case effluent quality range after proposed improvements to the WWTF treatment process.

(b) Based on 2.13 parts creek flow at CTR background concentrations “B” and 1 part effluent discharge at the forecast worst-case effluent quality range after the proposed improvements to the WWTF process.

(c) WQO = water quality objective.(d) Chronic/acute WQOs for ammonia (salmonids absent, but early life stages present) based on a maximum pH (1 day/30 day average) and maximum temperature

within that period for the blend of 8.0/7.9 and 10° C, respectively. These values are essentially independent of stream/effluent dilution ratios in this particular situation.

(e) Chronic/acute WQO based on a minimum blend hardness of 47 mg/L for these “concave down” metals.(footnotes continued on next page)

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(f) Chronic/acute WQO based on a minimum blend hardness of 54 mg/L for these “concave down” metals. Note, this is a reduction from Table 5 values. This reduction is based on lower Jackson Creek hardness values occurring in the June through September period not applicable to Table 5.

(g) Secondary MCL of 200 µg/L (average annual basis) governs based on stream hardness, see Table 5.(h) These background values “B” for these specific parameters are the same for Jackson Creek considering either year-round data (Table 15), or Oct-May seasonal data

(Table 5).(i) Based on upgrades to WWTF.

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