HomeMy WebLinkAbout12 Urban Water Management PlanAgenda Item # 12
CONSENT
To:
Board of Directors
From:
Neil Kaufman
Date:
June 01, 2011
Subject: Consideration of a Resolution to Adopt the Draft 2010 Urban Water
Management Plan
1. WHY THIS MATTER IS BEFORE THE BOARD
The California Water Code requires that the District prepare and adopt a 2010 Urban
Water Management Plan (UWMP).
2. HISTORY
The Urban Water Management Planning Act (California Water Code Section 10610)
requires that all urban water suppliers prepare urban water management plans and
update them every five years. The District is considered an urban water supplier since
it serves more than 3,000 customers.
Normally, an urban water supplier is required to update its plan at least once every
five years on or before December 31, in years ending in five and zero. However, the
December 31, 2010 deadline was extended until July 1, 2011 when the Water
Conservation Act of 2009 (SB 7X-7) was enacted. SB 7X-7 imposed additional
requirements regarding the 2010 UWMP.
The draft 2010 UWMP was been prepared by District staff and was presented to the
Board at the April 6, 2011 meeting. On May 4, 2011, a public hearing regarding the
draft UWMP was held. No comments were received.
3. NEW INFORMATION
To date, the only comments on the UWMP were submitted by the Tahoe Truckee
Sanitation Agency (TTSA). These comments are included as Attachment 1. District
staff has reviewed these comments and made revisions to the draft UWMP. In
addition, staff review of the UWMP determined that additional references to the
current Martis Valley Groundwater Management Plan and the update currently under
preparation were needed. Attachment 2 contains redline versions of the revised
Section 5 and Section 8 of the UWMP. The other sections are unchanged from the
draft UWMP presented on April 2011. Attachment 3 contains the complete revised
draft UWMP.
4. FISCAL IMPACT
There is no fiscal impact associated with adoption of the UWMP.
5. RECOMMENDATION
Approve the resoltuion for adoption of the 2010 Urban Water Management Plan.
Michael D. Holley
General Manager / Water Utility Manager
Resolution No. 2011 - XX
ADOPTION OF THE 2010 URBAN WATER
MANAGEMENT PLAN
WHEREAS, the California Legislature enacted Assembly Bill 797 (Water Code Section 10610 et
seq., known as the Urban Water Management Planning Act) during the 1983-1984 Regular
Session, and as amended subsequently, which mandates that every supplier providing water for
municipal purposes to more than 3,000 customers or supplying more than 3,000 acre feet of water,
prepare an Urban Water Management Plan, the primary objective of which is to plan for the
conservation and efficient use of water; and
WHEREAS, the District is an urban supplier of water providing water to over 3,000 customers; and
WHEREAS, the Plan shall be periodically reviewed at least once every five years, and that the
Truckee Donner Public Utility District shall make any amendments or changes to its plan which are
indicated by the review; and
WHEREAS, the District has therefore, prepared and circulated for public review a draft Urban
Water Management Plan, and a properly noticed public hearing regarding said Plan was held by
the Truckee Donner Public Utility District on May 4, 2011; and
WHEREAS, the Plan must be adopted by July 1, 2011 after the public review and hearing, and
filed with the California Department of Water Resources within thirty days of adoption; and
NOW, THEREFORE, BE IT RESOLVED by the Board of Directors of the Truckee Donner Public
Utility District as follows:
1. That the above recitations are true and correct.
2. That the 2010 Urban Water Management Plan is adopted.
PASSED AND ADOPTED by the Board of Directors at a meeting duly called and held within the
District on the first day of June, 2011 by the following roll call vote:
AYES:
NOES:
ABSTAIN:
ABSENT:
TRUCKEE DONNER PUBLIC UTILITY DISTRICT
Jeff Bender, President
ATTEST:
Michael D. Holley, Clerk of the Board
Urban Water Management Plan
Attachment 1- comments
TAHOE-TRUCKEE SANITATION AGENCY
A Public Agency
13720 Joerger Drive
Directors
TRUCKEE, CALIFORNIA 96161
O.R. Butterfield
(530) 587.2525 - FAX (530) 587.5840
Dale Cox
Erik Hennkson
S. Lane Lewis
Jon Northrop
0 5 -1 1- i t r:1 1:" 3 IN C V D
General Manager
Marcia A. Beals
VIA U.S. MAIL
09 May 2011
Mr. Neil Kaufinan
Truckee Donner Public Utilitv District
P.O. Box 309
Truckee, CA 96160
RE: Comments on Draft-1 0 10 Urban Water Management Plan
Dear Mr. Kaufman:
The Tahoe -Truckee Sanitation Agency (T-TSA) has reviewed the draft copy of the 2010 Urban
Water Management Plan (UWMP) and offers the following comments:
Y Section 5, Water Supply Sources, Section Entitled "Quantity of Groundwater in the
Vlartis Valley Basin", 3rd Paragraph, 3rd Line, Page 5-2:
♦ Text: "An additional 5,433 AFY is recharged to the upper layer of the MVGB by the
Tahoe -Truckee Sanitation Agency's (TTSA) wastewater treatment plant."
• Comment: The 5,433 acre-feet per year (AFY) figure amounts to 4.85 million gallons
per day (mgd). In the year 2010, T-TSA recharged the MVGB with 4,794 AFY based
on an annual average flow rate of 4.28 mgd.
Sect. -in F, Recycled Water Opp^rtunitieS Section- Entitled "Waste -water Quantities" 2st
, :3(.L a• � a.t „a �. v r , i ie.0 "Waste -water ssiWi Quantities",
Paragraph, 2°d Line, Page 8-1:
♦ Text: "The TTSA plant has a current capacity of 4.83 mgd and treats wastewater from the
entire Truckee/North Lake Tahoe area within the state of California."
• Comment: The T-TSA plant has a current rated capacity of 9.6 mgd on a peak -week
basis over the summer months.
Section 8, Recycled Water Opportunities, Section Entitled "Wastewater Treatment",
1st Paragraph, Page 8-2:
♦ 1" Sentence: "The treatment process at the TTSA plant involves full tertiary treatment
including phosphorus and ammonia removal."
Comment: To be more precise, "ammonia" should be substituted with "nitrogen".
NORTH TAHOE 9 TAHOE CITY - ALPINE SPRINGS - SQUAW VALLEY 9 TRUCKEE
♦ 2°d Sentence: "Treated effluent is discharged into the uppermost layer of the groundwater
aquifer using surface spray irrigation and subsurface percolation."
Comment: Currently, only subsurface percolation is used to discharge treated
effluent.
♦ 3rd Sentence: "Most of this water discharges from the aquifer into the Truckee River,
contributing about 6 feet per second to the flow of the river."
• Comment: There is no single discrete point source discharge of treated effluent from
the aquifer into the Truckee River. T-TSA would like to know the basis for this
"6 feet per second" contribution.
♦ 4t6 Sentence: "Sludge generated by the wastewater treatment process is conveyed to the
Lockwood Regional Landfill for disposal."
• Comment: Most of T-TSA's sludge is transported to Gerlach for disposal, some is
still hauled to Lockwood Regional Landfill for disposal.
➢ Section 8, Recycled Water Opportunities, Section Entitled "Current and Potential Use
of Recycled Water", Page 8-2:
♦ 1st Paragraph, V Sentence: "As noted above, all water treated at the TTSA plant is
discharged into the upper groundwater aquifer, through which it eventually flows into the
Truckee River."
Comment: As stated above, there is no single discrete point source discharge of
treated effluent from the aquifer into the Truckee River. See previous comment.
Thank you for the opportunity to provide comments on the draft document. If you have any
questions, please do not hesitate to call me at (530) 587-2525.
Sincerely,
J�lv
Marcia A. Beals
General Manager
JAP.jp
Urban Water Management Plan
Attachment 2
Redline versions of Section 5 and 6
SECTION 5
WATER SUPPLY SOURCES
Law
10630. It is the intention of the Legislature, in enacting this part, to permit levels of water management
planning commensurate with the numbers of customers served and the volume of water supplied.
10631. A plan shall be adopted in accordance with this chapter that shall do all of the following:
10631. (b) Identify and quantify, to the extent practicable, the existing and planned sources of water available to
the supplier over the same five-year increments [to 20 years or as far as data is available].
This section provides an evaluation of the available water supplies to meet the existing and
future water demands through buildout of the District's service area. Recommendations
necessary for the District to continue providing adequate water at acceptable quality are made for
both existing and future conditions.
MARTIS VALLEY GROUNDWATER BASIN
The District currently obtains its drinking water through the pumping of groundwater from the
Martis Valley Groundwater Basin (MVGB). The MVGB is a multiple aquifer system consisting
of basin -fill sedimentary units and interlayered basin -fill volcanic units. Detailed information
regarding geology of the MVGB can be found in a number of sources, including:
• Availability of Ground Water. Prepared for the Truckee Donner Public Utility District by
Hydro -Search Inc. Reno, Nevada. February 1975.
• Truckee and Vicinity Ground -Water Resource Evaluation. Prepared for Dart Resorts Inc.
by Hydro -Search Inc. Reno, Nevada. April 1980.
• Ground -Water Management Plan, Phase 1, Martis Valley Ground -Water Basin, Basin
No. 6-67, Nevada and Placer Counties. Prepared for the Truckee Donner Public Utility
District by Hydro -Search Inc. Reno, Nevada. January 1995.
• Ground Water Resource Evaluation. Prepared For The Truckee Donner Public Utility
District by Nimbus Engineers. Reno, Nevada. November 2000.
• Ground Water Availability In The Martis Valley Ground Water Basin, Nevada and Placer
Counties, California. Prepared for the Truckee Donner Public Utility District, Placer
County Water Agency and Northstar Community Services District by Nimbus Engineers.
Reno, Nevada. March 2001.
• Supplemental Report to California's Groundwater — Bulletin 118, Update 2003. Prepared
by the California Department of Water Resources. Sacramento, California. October
2003.
QUANTITY OF GROUNDWATER IN THE MARTIS VALLEY BASIN
A number of studies have been conducted over the past 30 years to investigate and quantify the
amount of water available in the MVGB. As knowledge regarding the geologic characteristics of
the MVGB has improved over the years, the estimates of available water have been refined and
Page 5-1
Section 5 — Water Supply Sources
therefore, the most recent studies are considered to have the best information regarding water
availability.
The 1975 study by Hydro -Search estimated annual recharge to the MVGB at 18,200 AFY with a
total subsurface storage volume of 1,050,000 acre-feet. The 1975 study also concluded that
13,000 AFY was available for consumptive uses. The 1980 and 1995 studies were essentially
updates of the 1975 study and provided additional information regarding the MVGB. However,
a new evaluation of groundwater availability was not conducted as part of those efforts.
The 2001 study represented the first reconsideration of the MVGB water availability since the
1975 study. This 2001 study concluded that total subsurface storage volume is 484,000 acre-
feet, with an annual recharge of 29,165 AFY. An additiena15,433AFrAdditional water is
recharged to the upper layer of the MVGB by the Tahoe -Truckee Sanitation Agency's
(TTS SA's) wastewater treatment plant. This 2001 study concluded that the sustainable
yield of the MVGB is 24,000 AFY.
In 2002, a study entitled Independent Appraisal of Martis Valley Ground Water Availability,
Nevada and Placer Counties was conducted by Kennedy/Jenks Consultants. This study agreed
with the sustainable yield estimate of 24,000 AFY by Nimbus Engineers in 2001. The
Kennedy/Jenks study also concluded that the 24,000 AFY likely underestimates the amount of
water available on a sustainable basis since the 2001 Nimbus study underestimated both basin
recharge and ground water discharge to tributary streams.
In April 2003, a study conducted by InterFlow Hydrology and Cordilleran Hydrology entitled
Measurement of Ground Water Discharge to Streams Tributary to the Truckee River in Mards
Valley, Nevada and Placer Counties, California examined the issue of ground water discharge
to tributary streams and concluded that about 34,000 AFY of water is available on a sustainable
basis.
The California Department of Water Resources has not determined that the MVGB is being
overdrafted and there are not any known instances of contamination of the MVGB. The MVGB
is currently unadjudicated and none of the groundwater users has expressed a desire to have the
basin adjudicated to date. Therefore, it is reasonable to assume that, at a minimum, the 24,000
AFY of water cited in the Nimbus study is available to support development in Truckee and the
surrounding areas.
RELIABILITY OF WATER SUPPLY
Currently, the major producers of water in the MVGB are the District, the Northstar Community
Services District, the Placer County Water Agency, Ponderosa Golf Course and Teichert
Aggregates. There are numerous small wells supporting individual residences along with some
other uses such as the Martis Creek Campground and the TNT Materials concrete plant.
For 2010, withdrawals from the MVGB by the District totaled 5,071 AF for potable water
purposes and an additional 604 AF for irrigation and construction water purposes. It is estimated
that an additional 1,500 AF was withdrawn by other users for a total withdrawal of 7,175 AFY.
Page 5-2
Section 5 — Water Supply Sources
As shown in Table 4-16, the total buildout average day water demand for the District is
projected at 10.10 mgd. Therefore, a sustainable water supply about 11,314 AFY will be
required to meet this buildout condition.
In February 2002, a technical memorandum entitled Water Demand and Net Depletion for
Maros Valley Groundwater Basin prepared by David Antonucci estimated buildout water
demand for all water producers throughout the MVGB at 20,953 AFY. This document projected
a buildout demand of 13,326 AFY for areas currently served by the District, with 7,610 AFY for
areas currently served by other agencies or individual wells. Assuming the 7,610 AFY estimate
for other parties is correct, a total of 18,924 AFY is needed to serve the entire region at buildout.
With a total water supply of at least 24,000 AFY, there is adequate water supply to meet the
projected buildout conditions. There are 484,000 acre-feet of water in storage in the MVGB.
The projected total demand of 18,924 AFY at buildout is equal to about four percent of the
capacity of the MVGB and there is adequate water to provide for over 20 years worth of demand
even if no recharge of the basin were to occur.
The great majority of groundwater basin recharge results from snowfall and snowmelt during the
winter period. Summer thunderstorms can produce high intensity rainfall events of short
duration. However, these storms do not make a significant contribution to basin recharge.
Figure 5-1 shows historic snowfall and snowpack data at Donner Summit for the period of 1879-
2010 as measured by the Central Sierra Snow Laboratory. As shown in this graph snowfall (and
corresponding basin recharge) can vary significantly from year to year. The driest single year
occurred in 1881 with total snowfall of about 13 feet. The 3-year period with the minimum
snowfall occurred in 1924-1926 with a total of about 54 feet. Considering the large amount of
water in storage in relation to the projected buildout demand, one year (or even multiple years)
of below average precipitation and basin recharge would not have a significant impact upon the
water supply. Therefore, the 24,000 AFY noted above is considered the 3-year minimum water
supply.
Local water resources are adequate to meet projected buildout conditions. Therefore, the
importation of water from other areas, water transfers and water exchanges have not been
investigated since they are unnecessary. Similarly, the use of desalinated water has not been
investigated. Considering that the Truckee area is about 200 miles from the ocean, the use of
desalination is considered extremely unpractical.
MANAGEMENT OF THE MARTIS VALLEY GROUNDWATER BASIN
As noted on Page 5-1, a management plan for the Martis Valley Groundwater Basin was
prepared in 1995. A copy of this groundwater management plan is included in Appendix C. An
updated groundwater basin management plan is currently under preparation and should be
completed in 2012. On April 6, 2011, the District's Board of Directors adopted a resolution of
intent to update the Martis Valley Groundwater Management Plan. A copy of that resolution is
also included in Appendix C.
Page 5-3
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Section 5 — Water Sunnly Sources
EXISTING WATER SUPPLY QUALITY
As noted in the District's 2010 Water Quality Report, all water supplied to potable water
customers is in compliance with State and Federal regulations. The District does operate
treatment systems at the Northside and Hirschdale wells. The treatment system at Northside
removes excess levels of arsenic. The treatment system at Hirschdale removes excess levels of
arsenic, iron and manganese. The quality of the existing sources has been consistent and the
District does not anticipate any future changes in the quality of its existing sources.
Page 5-5
Section 5 — Water Supply Sources
Page 5-6
Section 5 — Water SuDn1V Sources
EXISTING PRODUCTION CAPACITY IN RELATION TO PROJECTED DEMANDS
Current maximum day potable water demand is 9.53 mgd. It is anticipated that this maximum
day demand will increase to 10.9 mgd and 12.4 mgd by the years 2015 and 2020, respectively.
Average day potable water demand will increase from 4.53 mgd currently to 5.11 mgd in the
year 2015 and 5.81 mgd in the year 2020. The anticipated growth in potable water demand
shown graphically in Figure 5-2.
The District currently operates 12 potable water wells in the Truckee area and one in the
Hirschdale area. The total capacity of these wells is about 9,740 gpm (14.0 mgd). The overall
system potable water production capacity is adequate to serve projected demands through the
year 2023. However, the firm capacity of these existing facilities will be exceeded in the year
2015, since a failure of Airport Well would leave a production capacity of only 10.9 mgd.
IMPACT OF UPCOMING WATER QUALITY REGULATIONS
The Environmental Protection Agency (EPA) has been discussing additional regulations
regarding radon levels in drinking water for a number of years. Currently, radon is present in the
existing wells at levels below the existing maximums.
Preliminary announcements from USEPA have indicated that the maximum allowable radon
level will likely be reduced from 4,000 picocuries per liter (pCi/L) to 300 pCi/L. According to
the District's 2010 Water Quality Report, radon levels in its wells range from 293 to 1,600
pCi/L. The proposed radon level limit is under review and may be set at a level higher than 300
pCi/L. Two methods have been identified to address the proposed reduction in the allowable
radon level.
One method involves the removal of radon in the water by aeration. Treatment by aeration would
require the installation of separate aeration tanks and booster pumping stations at each well site.
This method would require a significant capital investment, along with incurring higher
operations and maintenance costs. Capital costs range from $100,000 to $150,000 for each well
site. Operation and maintenance costs are estimated at $0.05 per thousand gallons.
The second method is a Multimedia Mitigation Program proposed by the USEPA. The
Multimedia Mitigation Program addresses both water and air quality at the point of use. This
program has a limited involvement by the water provider and is focused mainly on air quality.
No cost estimates are available at this time, but it is anticipated that the Multimedia Mitigation
Program costs will be substantially lower than the cost of treatment by aeration. Therefore, it is
expected that the forthcoming radon regulations will have a minimal impact on the District's
water supply.
Page 5-7
Section 5 — Water Supply Sources
ADDITIONAL POTABLE WATER PRODUCTION CAPACITY
The available production capacity is sufficient to meet current demands. Based upon the
projected growth, the potable water production facilities will be unable to meet projected
maximum day demands in the year 2024. With the projected buildout maximum day potable
water demand of 20.3 mgd, an additional 9.4 mgd of potable water production capacity is needed
to meet buildout demands and to provide adequate firm capacity to the system.
Page 5-8
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Section 5 — Water Supply Sources
Based on the 14.0 mgd of total available capacity, an additional 2.8 mgd of production capacity
is needed over the next 20 years to meet projected demands. Furthermore, an additional 3.0 mgd
of capacity will be necessary to ensure that the system has adequate firm capacity. There are
three alternatives available to the District for additional water supply to meet this need:
• Construct additional wells not requiring filtration
• Construct additional wells requiring filtration
• Construct a surface water treatment facility
Historically, the District has used groundwater as its sole source of supply. Construction of a
surface water treatment plant to utilize surface water from Donner Lake was undertaken by a
developer in the early 1970s, but was halted due to political issues and questions regarding the
status of water rights. It is recommended that groundwater continue to be the main source of
supply.
Based on the studies cited at the beginning of this Section, the additional groundwater wells can
be constructed without exceeding the sustainable yield of the groundwater basin. Construction
of new wells is expected to be the near -term solution to increasing water supply. As further
development occurs in adjoining areas of the Martis Valley, the overall withdrawals from the
basin will need to be balanced with the sustainable yield. The other two water supply options
require additional investigations of technical, legal and regulatory issues.
RECOMMENDED IMPROVEMENTS
Based on the expected increase in water demand, a number of water production improvements
are recommended. These improvements are listed in Table 5-1. In the short-term, construction
of new wells not requiring filtration is the most reasonable alternative to pursue. For the
purposes of water supply planning, it is assumed that new wells will have a capacity of 850 gpm
each. If the capacity of new wells differs significantly from this 850 gpm value, the
recommendations given herein should be adjusted accordingly.
The proposed phasing given in Table 5-1 is based on anticipated growth in demand throughout
the service area. An additional eight wells will be needed to serve buildout conditions with
adequate firm capacity. These wells should be constructed as growth and increases in water
demand dictate. Figure 5-3 gives the relationship of projected demand to the recommended
water production improvements.
- -
- _
- - EPFFB&- ---- --
0-41010-00
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----- - - -- -- ---- - -- -
Page 5-10
Section 5 - Water Supplv Sources
Table 5-1. Recommended Potable Water Production Improvements
Year
Maximum Day
Demand an d
Total
Production
Capacity,an d
Firm Production
Capacity,an d
Notes
2010
9.53
14.0
10.9
2011
9.79
14.0
10.9
2012
10.06
14.0
10.9
2013
10.33
14.0
10.9
2014
10.60
14.0
10.9
2015
10.87
14.0
10.9
2016
11.14
15.2
12.2
New 850 gpm Well Constructed
2017
11.45
15.2
12.2
2018
11.76
15.2
12.2
2019
12.07
15.2
12.2
2020
12.38
16.5
13.4
New 850 gpm Well Constructed
2021
12.82
16.5
13.4
2022
13.26
16.5
13.4
2023
13.70
17.7
14.6
New 850 gpm Well Constructed
2024
14.14
17.7
14.6
2025
14.58
17.7
14.6
2026
15.02
18.9
15.8
New 850 gpm Well Constructed
2027
15.46
18.9
15.8
2028
15.90
20.1
17.1
New 850 gpm Well Constructed
2029
16.34
20.1
17.1
2030
16.78
20.1
17.1
Buildout
20.30
23.8
20.7
In 2002 and 2003, the District drilled a number of exploration wells in order to identify locations
for future groundwater wells. As a result of this exploration well program the District acquired
four well sites. The Prosser Village Well was constructed in 2004 and the Old Greenwood Well
was constructed in 2006 at two of these sites.
The Fibreboard Well was constructed in 2009 at the third site. The water_moduced by this wel
exceeds the MCL for arsenic and is considered non -potable water. However this water is
perfectly suited for irrigation pMoses and supplies water to the Gray's Crossing and Old
Greenwood golf courses. This well allowed for the removal of about 1.3 mad of maximum day
demand from the potable water system.
There is one remaining well site where property rights have been secured by the District. It is
expected that the new finite element model under development by Brown and Caldwell will
provide information regarding behavior of the groundwater basin. Once this model and the
accompanying study are completed, the District should have sufficient information to identify
additional well sites and can investigate the drilling of additional test wells.
Page 5-11
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Section 5 — Water Supply Sources
It should also be noted that some of the existing wells may be reaching the end of their useful
lives towards the year 2025. Production from the wells should be monitored over time and
redevelopment of existing wells may be necessary to maintain an adequate water supply. Of
particular concern is the long-term viability of the existing Airport Well. The existing wellhole
and casing are not completely vertical and there is a significant offset in the casing. As a result
of this offset, the well shaft experiences accelerated wear and requires replacement every four
years.
The use of surface water, either through a treatment plant or wells with filtration, requires that a
number of technical, legal and environmental issues be investigated and addressed. Surface
water should be considered a long-term water supply option and may prove to be more cost-
effective than new wells as demand approaches buildout conditions.
Page 5-13
SECTION 8
RECYCLED WATER OPPORTUNITIES
Law
10633. The plan shall provide, to the extent available, information on recycled water and its potential for use
as a water source in the service area of the urban water supplier. To the extent practicable, the
preparation of the plan shall be coordinated with local water, wastewater, groundwater, and planning
agencies and shall include all of the following:
10633. (a) A description of the wastewater collection and treatment systems in the supplier's service area,
including a quantification of the amount of wastewater collected and treated and the methods of
wastewater disposal.
10633. (b) A description of the recycled water currently being used in the supplier's service area, including but not
limited to, the type, place and quantity of use.
10633. (c) A description and quantification of the potential uses of recycled water, including, but not limited to,
agricultural irrigation, landscape irrigation, wildlife habitat enhancement, wetlands, industrial reuse,
groundwater recharge, and other appropriate uses, and a determination with regard to the technical and
economic feasibility of serving those uses.
10633. (d) The projected use of recycled water within the supplier's service area at the end of 5, 10, 15, and 20
years.
The District does not provide either wastewater collection or treatment to customers within its
service area. The great majority of the District's water customers are served by a centralized
wastewater collection system owned by the Truckee Sanitary District (TSD). This TSD
maintained system collects the wastewater and conveys it to the Tahoe -Truckee Sanitation
Agency's (TTSA) regional water reclamation plant.
The remainder of the District's water customers is not served by centralized wastewater
collection and treatment. Water customers in the Olympic Heights, Prosser Heights, Prosser
Lakeview, Ponderosa Palisades and Martiswoods areas are served by individual septic tank and
leachfield systems. In recent years, TSD has been expanding its collection system into the Sierra
Meadows subdivision. TSD also provides wastewater conveyance service for portions of Placer
County outside of the District's service area.
WASTEWATER QUANTITIES
All wastewater collected by TSD is conveyed to the TTSA Water Reclamation Plant for
treatment. The TTSA plant has a eufrentpgak capacity of 4-.839_6 mgd and treats wastewater
from the entire Truckee/North Lake Tahoe area within the state of California. As of January
2011, TSD conveyed about 1.9 million gallons per day (mgd) of wastewater to the treatment
plant under average day conditions with a flow of about 3.3 mgd under peak day conditions.
About 80 percent of TSD's current total wastewater flow is generated within the District's water
service territory. No data is available to quantify the amount of wastewater treated by individual
septic tank and leachfield systems.
TSD has projected buildout wastewater flows under average day conditions at 3.6 mgd with
corresponding peak flow conditions at 6.4 mgd. These buildout flows include areas outside the
District's service territory. TSD projects about 70 percent of the total flows will be generated in
Page 8-1
Section 8 — Recycled Water Opportunities
the District's water service territory at buildout. TSD currently projects buildout within its
service territory will occur in the year 2050.
TSD has not developed interim flow projections between current and buildout conditions.
Therefore, the District developed interim wastewater flow projections based on the data
described above. These projections are given in Table 8-1.
Table 8-1. Wastewater Flow Projections
for the District's Water Service Area
Year
Average Day Flow
Peak Day Flow
2010
1.5 mgd
2.6 mgd
2015
1.6 mgd
2.8 mgd
2020
1.8 mgd
3.1 mgd
2025
1.9 mgd
3.3 mgd
2030
2.0 mgd
3.6 mgd
Buildout
2.5 mgd
4.5 mgd
WASTEWATER TREATMENT
The treatment process at the TTSA plant involves full tertiary treatment including phosphorus
and anwaonianitrog_en removal. Treated effluent is discharged into the uppermost layer of the
groundwater aquifer using stiffaee spray ir6gatiea and subsurface percolation. Most of *'���
wa4er- disehe&ges from the aquifer- inte the Tnaekee River, eentributing abeut 6 feet per- seeend to
the flow e f the r-iver-. Sludge generated by the wastewater treatment process is conveyed to either
Orient Farms in Gerlach, Nevada, or the Lockwood Regional Landfill for disposal.
CURRENT AND POTENTIAL USE OF RECYCLED WATER
As noted above, all water treated at the TTSA plant is discharged into the upper groundwater
aquifer, .,..,,ugh •..hieh it eventually flows rote the T fidekee Rive Currently, there is no usage
of recycled water for commercial, industrial or irrigation purposes within the District's service
territory.
In November 1990, the Truckee -Carson -Pyramid Lake Water Rights Settlement Act, Title II of
Public Law 101-618 [104 Stat. 3289, 3294] was signed into law by the US Government. Section
204.c.1.G of that Act essentially prohibits the reduction in return flow of treated wastewater to
the Truckee River and thereby precludes opportunities for the use of recycled water. The text of
the Section is given below:
G) if the Tahoe -Truckee Sanitation Agency or its successor (hereafter 'TTSA') changes in whole or in
part the place of disposal of its treated wastewater to a place outside the area between Martis Creek
and the Truckee River below elevation 5800 NGVD Datum, or changes the existing method of
disposing of its wastewater, which change in place or method of disposal reduces the amount or
substantially changes the timing of return flows to the Truckee River of the treated wastewater,
TTSA shall:
(i) acquire or arrange for the acquisition of preexisting water rights to divert and use water of the
Truckee River or its tributaries in California or Nevada and discontinue the diversion and use
Page 8-2
Section 8 — Recycled Water Opportunities
of water at the preexisting point of diversion and place of use under such rights in a manner
legally sufficient to offset such reduction in the amount of return flow or change in timing,
and California's Truckee River basin gross diversion allocation shall continue to be charged
the amount of the discontinued diversion; or
(ii) in compliance with California law, extract and discharge into the Truckee River or its
tributaries an amount of Truckee River basin groundwater in California sufficient to offset
such reduction or change in timing, subject to the following conditions:
(a) extraction and discharge of Truckee River Basin groundwater for purposes of this
paragraph shall comply with the terms and conditions of subparagraphs 204(c)(1) (B)
and (D) and shall not be deemed use of Truckee River basin groundwater within the
State of Nevada within the meaning of subparagraph 204(c)(1)(D); and
(b) California's Truckee River basin gross diversion allocation shall be charged
immediately with the amount of groundwater discharged and, when California's
Truckee River Basin gross diversion allocation equals 22,000 acre-feet or when the
total of any reductions resulting from the changes in the place or method of disposal
exceed 1000 acre-feet, whichever occurs first, the California Truckee River basin gross
diversion allocation shall thereafter be charged with an additional amount of water
required to compensate for the return flows which would otherwise have accrued to the
Truckee River basin from municipal and industrial use of the discharged groundwater.
In no event shall the total of California's Truckee River gross diversions and extractions
exceed 32,000 acre-feet.
(iii) For purposes of this paragraph, the existing method of disposal shall include, in addition to
underground leach field disposal, surface spray or sprinkler infiltration of treated wastewater
on the site between Martis Creek and the Truckee River referred to in this subsection.
(iv) The provisions of this paragraph requiring the acquisition of water rights or the extraction and
discharge of groundwater to offset reductions in the amount or timing of return flow to the
Truckee River shall also apply to entities other than TTSA that may treat and dispose of
wastewater within the California portion of the Truckee River basin, but only if and to the
extent that the treated wastewater is not returned to the Truckee River or its tributaries, as to
timing and amount, substantially as if the wastewater had been treated and disposed of by
TTSA in its existing place of disposal and by its existing method of disposal. The provisions
of this paragraph shall not apply to entities treating and disposing of the wastewater from less
than eight dwelling units.
Page 8-3
Urban Water Management Plan
Attachment 3
Revised Draft