Wastewater Treatment Facility and Effluent Disposal Improvements
Table of Contents
1.0
1.1
1.2
1.3
PROJECT DESCRIPTION .................................................................................................. 1
PROJECT OBJECTIVE ...................................................................................................... 1
MEANS OF COMPLIANCE ................................................................................................. 2
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. .........................20
1.3.5
Other Alternatives Considered but Dismissed by the City ....................................25
FIGURES:
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
City of Jackson Wastewater Treatment Facility Improvements Proposed Project –
WWTF Physical Improvements ................................................................................11
City of Jackson Wastewater Treatment Facility Improvements Proposed Project –
Offsite Physical Improvements.................................................................................12
City of Jackson Wastewater Treatment Facility Improvements Alternative A – WWTF
Physical Improvements ............................................................................................15
City of Jackson Wastewater Treatment Facility Improvements Alternative B – WWTF
Physical Improvements ............................................................................................19
City of Jackson Wastewater Treatment Facility Improvements Alternative C – WWTF
Physical Improvements ............................................................................................23
City of Jackson Wastewater Treatment Facility Improvements Alternative C – Offsite
Physical Improvements ............................................................................................24
TABLES:
Table 1
Table 2
Table 3
Table 3
Table 4
Table 4
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 ....................................................................................................27
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 .......................................................28
Proposed Project – Regulatory Concerns and Means of Compliance ......................29
Proposed Project – Regulatory Concerns and Means of Compliance (continued)....30
Proposed Project – Physical Plant Improvements ....................................................31
Proposed Project – Physical Plant Improvements (continued) .................................32
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Wastewater Treatment Facility and Effluent Disposal Improvements
Table 5
Table 5
Table 5
Table 6
Table 6
Table 7
Table 8
Table 9
Table 10
Table 10
Table 11
Table 12
Table 12
Table 12
Table 13
Table 14
Table 15
Proposed Project – Estimates of Possible Changes in Water Resource Quantity and
Quality .....................................................................................................................33
Proposed Project – Estimates of Possible Changes in Water Resource Quantity and
Quality (continued)...................................................................................................34
Proposed Project – Estimates of Possible Changes in Water Resource Quantity and
Quality (continued)...................................................................................................35
Alternative A – Regulatory Concerns and Means of Compliance .............................36
Alternative A – Regulatory Concerns and Means of Compliance (continued)...........37
Alternative A – Physical Plant Improvements ...........................................................38
Alternative A – Estimates of Possible Changes in Water Resource Quantity and
Quality .....................................................................................................................39
Alternative B – Estimated Effluent Land and Storage Application Needs for Worst
Case Conditions ......................................................................................................40
Alternative B – Regulatory Concerns and Means of Compliance .............................41
Alternative B – Regulatory Concerns and Means of Compliance (continued)...........42
Alternative B – Physical Plant Improvements ...........................................................41
Alternative B – Estimates of Possible Changes in Water Resource Quantity and
Quality .....................................................................................................................42
Alternative B – Estimates of Possible Changes in Water Resource Quantity and
Quality (continued)...................................................................................................43
Alternative B – Estimates of Possible Changes in Water Resource Quantity and
Quality (continued)...................................................................................................44
Alternative C – Regulatory Concerns and Means of Compliance .............................45
Alternative C – Physical Plant Improvements...........................................................46
Alternative C – Estimates of Possible Changes in Water Resource Quantity and
Quality .....................................................................................................................47
ii
Wastewater Treatment Facility and Effluent Disposal Improvements
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. R52007-0133 (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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Wastewater Treatment Facility and Effluent Disposal Improvements
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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Wastewater Treatment Facility and Effluent Disposal Improvements
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 yearround 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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Wastewater Treatment Facility and Effluent Disposal Improvements
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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Wastewater Treatment Facility and Effluent Disposal Improvements
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, dilutionbased, 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.
5
Wastewater Treatment Facility and Effluent Disposal Improvements
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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Wastewater Treatment Facility and Effluent Disposal Improvements

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
7
Wastewater Treatment Facility and Effluent Disposal Improvements
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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Wastewater Treatment Facility and Effluent Disposal Improvements

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
9
Wastewater Treatment Facility and Effluent Disposal Improvements
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.
10
Wastewater Treatment Facility and Effluent Disposal Improvements
Figure 1
City of Jackson Wastewater Treatment Facility Improvements
Proposed Project – WWTF Physical Improvements
11
Wastewater Treatment Facility and Effluent Disposal Improvements
Figure 2
City of Jackson Wastewater Treatment Facility Improvements
Proposed Project – Offsite Physical Improvements
12
Wastewater Treatment Facility and Effluent Disposal Improvements
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
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.
13
Wastewater Treatment Facility and Effluent Disposal Improvements
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.
14
Wastewater Treatment Facility and Effluent Disposal Improvements
Figure 3
City of Jackson Wastewater Treatment Facility Improvements
Alternative A – WWTF Physical Improvements
15
Wastewater Treatment Facility and Effluent Disposal Improvements
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
16
Wastewater Treatment Facility and Effluent Disposal Improvements
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.
17
Wastewater Treatment Facility and Effluent Disposal Improvements
18
Wastewater Treatment Facility and Effluent Disposal Improvements
Figure 4
City of Jackson Wastewater Treatment Facility Improvements
Alternative B – WWTF Physical Improvements
19
Wastewater Treatment Facility and Effluent Disposal Improvements
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
to be used (earthen or concrete) will need to be determined by geotechnical and dam
20
Wastewater Treatment Facility and Effluent Disposal Improvements
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.
21
Wastewater Treatment Facility and Effluent Disposal Improvements
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.
22
Wastewater Treatment Facility and Effluent Disposal Improvements
Figure 5
City of Jackson Wastewater Treatment Facility Improvements
Alternative C – WWTF Physical Improvements
23
Wastewater Treatment Facility and Effluent Disposal Improvements
Figure 6
City of Jackson Wastewater Treatment Facility Improvements
Alternative C – Offsite Physical Improvements
24
Wastewater Treatment Facility and Effluent Disposal Improvements
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.
25
Wastewater Treatment Facility and Effluent Disposal Improvements
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.
26
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 1
Proposed 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
Year
Average
Year
Somewhat Dry
Year (15% Water
Conservation)
1Q10 Dry Year
(15% Water
Conservation)
Critical Drought
(20% Water
Conservation) (b)
40.64
40.64
30.32
25.52
19.58
10.61
35.35
35.35
26.38
22.20
17.03
9.23
----
----
----
2008-2009
----
1976-1977
6082
6082
3500
2008
1227
Assumed 0
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
Rainfall on Upper Watershed, inches/year (c)
Rainfall at Busi Ranch, inches/year
(d)
Representative Disposal Year (June to May)
Creek Flow at WWTF, Mgal/year
Total Runoff to Lake, Mgal/year
(f)
(g)
(e)
(a)
See text for all input variables to the effluent water balance model.
(b)
(c)
No significant I/I in critical drought because of lack of rain.
Estimated average rainfall over upper watershed = rainfall at Camp Pardee weather station (CPD) x 1.46.
(d)
(e)
Estimated rainfall at Busi Ranch disposal area = rainfall at Camp Pardee weather station (CPD) x 1.27.
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.
Projected annual creek flow based on annual rainfall and runoff relationships observed in 2003-2011.
(f)
(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.
27
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 2
Proposed 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
Year
Average
Year
Somewhat Dry
Year (15% Water
Conservation)
1Q10 Dry Year
(15% Water
Conservation)
Critical Drought
(20% Water
Conservation) (b)
40.64
40.64
30.32
25.52
19.58
10.61
35.35
35.35
26.38
22.20
17.03
9.23
----
----
----
2008-2009
----
1976-1977
6082
6082
3500
2008
1227
Assumed 0
8515
8515
4900
2811
1718
Assumed 0
Average Dry Weather Effluent Flow, Mgal/d
0.47
0.47
0.47
0.40
0.40
0.37
Total Effluent Flow, Mgal/yr
213
204
204
172
172
135
Total Effluent Discharge to Creek, Mgal/yr
135
135
123
94
73
0
Effluent as a % of Total Inflow to Lake
1.6
1.6
2.4
3.2
4.1
0
Total Effluent to Busi Ranch, Mgal/yr
78
69
81
78
99
135
Overall Site Soil Perc Rate, inch/day
0.035
0.035
0.035
0.035
0.035
0.035
Effluent Storage Volume, Mgal
30
30
30
30
30
30
Effluent Application Area, acres
135
120
125
115
130
150
Rainfall on Upper Watershed, inches/year (c)
Rainfall at Busi Ranch, inches/year
(d)
Representative Disposal Year (June to May)
Creek Flow at WWTF, Mgal/year (f)
Total Runoff to Lake, Mgal/year
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(g)
(e)
See text for all input variables to the effluent water balance model.
No significant I/I in critical drought because of lack of rain.
Estimated average rainfall over upper watershed = rainfall at Camp Pardee weather station (CPD) x 1.46.
Estimated rainfall at Busi Ranch disposal area = rainfall at Camp Pardee weather station (CPD) x 1.27.
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.
Projected annual creek flow based on annual rainfall and runoff relationships observed in 2003-2011.
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.
28
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 3
Proposed 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



Dichlorobromomethane (DCBM) and
Cyanide



Coliform and Turbidity


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.
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.
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)
29
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 3
Proposed Project – Regulatory Concerns and Means of Compliance (continued)
Regulatory Concern
Basin Plan objective to avoid effluent
dominated conditions in surface waters
Basin Plan objective to maximize
reclamation and land disposal of effluent,
and minimize effluent discharges to surface
waters
Division of Water Rights approval




Means of Compliance
Reduce effluent discharges to Jackson Creek such that the creek never contains more than 50%
effluent.
Reclaim and land apply effluent the extent reasonable.
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.
30
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 4
Proposed 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.
(continued on next page)
31
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 4
Proposed 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 offsite 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.
32
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 5
Proposed Project – Estimates of Possible Changes in Water Resource Quantity and Quality
Water Resource
Lake Amador
Estimates of Possible Changes
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).
Jackson Creek Flows, Average Mgal/d
Estimated Flows Downstream of WWTF
with the Proposed Project
2008-2009
10-year
Critical
Downstream
Status Quo
2008-2009
June
0.80
0.02
0
1.20
0.80
0.02
0
July
0.19
0.00
0
0.58
0.19
0.00
0
August
0.01
0.00
0
0.40
0.01
0.00
0
September
0.03
0.00
0
0.43
0.03
0.00
0
October
0.53
0.00
0
0.94
0.64
0.00
0
November
2.20
0.93
0
2.66
2.36
1.00
0
December
3.88
2.20
0
4.35
4.17
2.37
0
January
6.45
4.81
0
6.97
6.78
4.99
0
February
20.86
12.91
0
21.56
21.56
13.61
0
March
23.94
17.07
0
24.56
24.56
17.69
0
April
4.24
2.30
0
4.69
4.69
2.73
0
May
3.91
0.66
0
4.37
4.37
0.93
0
Mgal/year
2008
1227
386*
2269
2102
1300
386*
Year/Month
Estimated Flows Upstream of WWTF
2008-2009
10-year
Critical
2008
2009
*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.
(continued on next page)
33
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 5
Proposed 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.
Forecast Jackson Creek Water Quality Range: Oct through May
Parameter
Downstream Creek
Status Quo (a)
Downstream Creek with
Proposed Project (b)
Oct – May
“Background”
Creek Quality
Per SIP (h)
WQO (c)
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)
<2-8.2
<1.5-3.5
1.3
5.2/22 (g)
<0.37-0.82
<0.23-0.35
<0.16
0.56
Cyanide (µg/l)
Dichlorobromomethane (µg/l)
(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 OctMay seasonal data (Table 5).
(continued on next page)
34
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 5
Proposed 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.
San Andreas Shallow Groundwater Quality
Groundwater Quality
Parameter
Tuolumne City Shallow Groundwater Quality
Upgradient of Effluent
Application
Downgradient of Effluent
Application
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
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 6
Alternative A – Regulatory Concerns and Means of Compliance
Regulatory Concern
More than 5% effluent from time-to-time in a potable
water supply
Means of Compliance



Nitrate and Ammonia



Copper and Zinc



Dichlorobromomethane and Cyanide


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.
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 measures do not result in compliance, then add denitrification basins and
associated pumps and piping to the front end of the treatment process.
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.
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).
(continued on next page)
36
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 6
Alternative A – Regulatory Concerns and Means of Compliance (continued)
Regulatory Concern
Means of Compliance
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
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 7
Alternative 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
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 8
Alternative A – Estimates of Possible Changes in Water Resource Quantity and Quality
Water Resource
Lake Amador
Estimates of Possible Changes
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.
Forecast Jackson Creek Water Quality Range
Parameter
Nitrate (mg/L) (as NO3)
Ammonia (mg/L) (as N)
Downstream Creek
Status Quo
Downstream Creek
With Alternative A
WQO (a)
4.0-62
4.0-45 (b)
45
<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)
<2-8.2
<2-5.2 (b)
5.2/22 (g)
<0.37-0.82
<0.37-0.56 (b)
0.56
Cyanide (µg/L)
Dichlorobromomethane (µg/L)
(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
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 9
Alternative 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
Average
Year
1Q10 Dry Year
(15% Water
Conservation)
Critical Drought
(20% Water
Conservation) (b)
Average
Year
1Q10 Dry Year
(15% Water
Conservation)
Critical Drought
(20% Water
Conservation) (b)
30.32
19.58
10.61
30.32
19.58
10.61
26.38
17.03
9.23
26.38
17.03
9.23
3500
1227
Assumed 0
3500
1227
Assumed 0
4900
1718
Assumed 0
4900
1718
Assumed 0
Average Dry Weather Effluent Flow,
Mgal/d
0.71
0.60
0.57
0.47
0.40
0.37
Total Effluent Flow, Mgal/yr
309
261
208
204
172
135
Total Effluent Discharge to Creek,
Mgal/yr
222
188
139
146
124
90
Total Effluent to Busi Ranch, Mgal/yr
88
73
69
58
48
45
0.035
0.035
0.035
0.035
0.035
0.035
Effluent Storage Volume, Mgal
5
5
5
5
5
5
Effluent Application Area, acres
155 (g)
130
120
95 (g)
80
75
Climatic Condition and Extent of
Water Conservation
Rainfall on Upper Watershed,
inches/year (c)
Rainfall at Busi Ranch, inches/year (d)
Creek Flow at WWTF, Mgal/year
Total Runoff to Lake, Mgal/year
(e)
(f)
Overall Site Soil Perc Rate, inches/day
(a)
(b)
See text for all input variables to the effluent water balance model.
No significant I/I in critical drought.
(c)
(d)
Estimated average rainfall over upper watershed = rainfall at Camp Pardee weather station (CPD) x 1.46.
Estimated rainfall at Busi Ranch disposal area = rainfall at Camp Pardee weather station (CPD) x 1.27.
(e)
(f)
Projected annual creek flow based on annual rainfall and runoff relationships observed in 2003-2011.
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.
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.
(g)
40
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 10
Alternative B – Regulatory Concerns and Means of Compliance
Regulatory Concern
More than 5% effluent from time-to-time
in a potable water supply
Means of Compliance


Nitrate and Ammonia



Copper and Zinc


Dichlorobromomethane (DCBM) and
Cyanide



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.
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 add denitrification basins ahead of the oxidation ditches as
described under Alternative A.
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.
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).
(continued on next page)
41
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 10
Alternative B – Regulatory Concerns and Means of Compliance (continued)
Regulatory Concern
Coliform and Turbidity
Means of Compliance


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.
Basin Plan objective to avoid effluent
dominated conditions in surface waters

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
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 11
Alternative B – Physical Plant Improvements
Alternative B 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.
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.
41
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 12
Alternative B – Estimates of Possible Changes in Water Resource Quantity and Quality
Water
Resource
Lake Amador
Estimates of Possible Changes
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.
Jackson Creek Flows, Average Mgal/d
Estimated Flows Downstream of WWTF
with the Proposed Project
2008-2009
10-year
Critical
Downstream
Status Quo
2008-2009
June
0.80
0.02
0
1.20
0.80
0.02
0
July
0.19
0.00
0
0.58
0.19
0.00
0
August
0.01
0.00
0
0.40
0.01
0.00
0
September
0.03
0.00
0
0.43
0.03
0.00
0
October
0.53
0.00
0
0.94
0.64
0.41
0.37
November
2.20
0.93
0
2.66
2.36
1.39
0.37
December
3.88
2.20
0
4.35
4.17
2.67
0.37
Year/Month
Estimated Flows Upstream of WWTF
2008-2009
10-year
Critical
2008
2009
January
6.45
4.81
0
6.97
6.78
5.33
0.37
February
20.86
12.91
0
21.56
21.56
13.61
0.37
March
23.94
17.07
0
24.56
24.56
17.69
0.37
April
4.24
2.30
0
4.69
4.69
2.75
0.37
May
3.91
0.66
0
4.37
4.37
1.12
0.37
Mgal/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.
(continued on next page)
42
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 12
Alternative B – Estimates of Possible Changes in Water Resource Quantity and Quality (continued)
Water Resource
Jackson Creek
Estimates of Possible Changes
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.
Forecast Jackson Creek Water Quality Range: Oct through May
Parameter
Nitrate (mg/L) (as NO3)
Ammonia (mg/L) (as N)
Downstream Creek
Status Quo
Downstream Creek
With Alternative B
WQO (a)
4.0-62
4.0-45 (b)
45
<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)
<2-8.2
<2-5.2 (b)
5.2/22 (g)
<0.37-0.82
<0.37-0.56 (b)
0.56
Cyanide (µg/L)
Dichlorobromomethane (µg/L)
(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.
(continued on next page)
43
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 12
Alternative B – Estimates of Possible Changes in Water Resource Quantity and Quality (continued)
Water Resource
Busi Ranch
Groundwater
Estimates of Possible Changes
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.
San Andreas Shallow Groundwater Quality
Groundwater Quality Parameter
Upgradient of Effluent
Application
Tuolumne City Shallow Groundwater Quality
Downgradient of Effluent
Application
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
44
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 13
Alternative C – Regulatory Concerns and Means of Compliance
Regulatory Concern
Means of Compliance
More than 5% effluent from time-to-time in a
potable water supply

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.
Basin Plan objective to avoid effluent dominated
conditions in surface waters

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.

45
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 14
Alternative C – Physical Plant Improvements
Alternative C 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.
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.
46
Wastewater Treatment Facility and Effluent Disposal Improvements
Table 15
Alternative 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.
Forecast of Worst-Case Quality Range (i)
Parameter
Nitrate (mg/l) (as NO3)
(d)
(e)
3.4
Alternative C with 2.13:1
Dilution (b)
Creek
WQO (c)
Creek
WQO (c)
3.4-6.3
45
3.6-22
45
<0.77-2.5
2.8/8.4 (d)
0.9
<0.88-1.2
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)
<2-8.2
1.3
<1.3-1.6
5.2/22
<1.5-3.5
5.2/22
<0.37-0.82
<0.16
<0.17-0.19
0.56
<0.23-0.35
0.56
Dichlorobromomethane (µg/l)
(c)
4.0-62
Alternative C with 19:1
Dilution (a)
<0.5-6
Cyanide (µg/l)
(b)
Year-Round
“Background” Creek
Quality per SIP (h)
2.8/8.4 (d)
Ammonia (mg/l) (as N)
(a)
Status Quo when
Creek is 100%
Effluent
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.
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.
WQO = water quality objective.
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.
Chronic/acute WQO based on a minimum blend hardness of 47 mg/L for these “concave down” metals.
(footnotes continued on next page)
47
Wastewater Treatment Facility and Effluent Disposal Improvements
(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)
(h)
Secondary MCL of 200 µg/L (average annual basis) governs based on stream hardness, see Table 5.
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.
48