HomeMy WebLinkAboutRES 2008-07 - Board TRUCKEE
O r
Resolution No. 2008= 07
Adoption of a Water Supply Assessment
for the Truckee Railyard Master Plan project
WHEREAS, Truckee Development Associates is proposing to construct a project entitled the
"Truckee Railyard Master Plan" in the eastern portion of downtown Truckee; and
WHEREAS, the Town of Truckee has determined that preparation of a Water Supply Assessment
is required as described in the California Water Code Section 10910; and
WHEREAS, the Truckee Donner Public Utility District is the public water system that will provide
water service to the project; and
WHEREAS, the Town of Truckee has requested that the Truckee Donner Public Utility District
prepare a Water Supply Assessment for the "Truckee Railyard Master Plan" project; and
WHEREAS, the Truckee Donner Public Utility District's Water Department has prepared the
Water Supply Assessment for the "Truckee Railyard Master Plan" project:
NOW THEREFORE BE IT RESOLVED by the Board of Directors of the District as follows:
The Truckee Donner Public Utility District hereby adopts the Water Supply Assessment for the
Truckee Railyard Master Plan project.
PASSED AND ADOPTED by the Board of Directors at a meeting duly called and held within the
District on the 21 st of May, 2008 by the following roll call vote:
AYES: Director Aguera, Taylor and Thomason
NOES: None
ABSTAIN: Director Sutton
ABSENT: Director Hemig
TRUCKEE DONNER PUBLIC UTILITY DISTRICT
By =�
Tim Taylor, Presi
ATTEST:
Michael D. Holley, District Clerk
INTRODUCTION
This Water Supply Assessment(WSA)has been prepared by Truckee Donner Public Utility
•UCKEE . District(District)for the Railyard Master Plan project at the request of the Town of Truckee
This WSA is intended to satisfy the requirements of California Water Code Sections 10910
through 10914 and to provide factual information regarding the ability of the District's water
supplies to meet the water demands associated with the proposed project
BACKGROUND
The Railyard Master Plan involves redevelopment of partially developed property located along
the eastern end of downtown Truckee. The general location of the project is shown in Figure 1.
The project consists of.
_ • A 60 room hotel
• A 1,000 seat movie theater
• 70,000 square feet of retail space
P • 545 residential units in some form of multi-fan►ily/condoiattached housing.
• 25 single family residential units
• 15,000 square feet of office space
TRUCKEE RAILYARD MASTER PLAN . A 20,000 square feet grocery store
WATER SUPPLY ASSESSMENT • 25,000 square feet of civic use space
PROJECT WATER DEMAND
The District's 2004 Water Master Plan identified the project site as a location for future
development. Detailed plans had not been prepared for the site at that time. An average day
water demand of 136,160 gallons per day(gpd)was projected based upon 34.04 acres at 4,000 - -y
gallons per acre per day. That projected demand was then incorporated into the District's 200.5
Urban Water Management Plan(UWMP).
ADOPTEDBased upon current information,an average day demand of 362,640 gpd is now expected. A
XXXX 2008 breakdown of this amount is given in Table 1.
Table 1. Projected Rail and Water Demand
Type Quantity Unit Demand_ Total
Hotel 60 234 gals/room 14,040
Movie Theater 1,000 3 gals/seat 3,000
Commercial 105,000 0.4 gals/SF 42,000
Multi-Family Residential 545 455 gals/unit 247.975
Single Family Residential 25 505 gals/unit 12,625
Civic Use 25,000 0.4 gals/SF 10,000
Other Uses 33,000
Total I ------ -- --------_362,640
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 number of customers served and the volume of water supplied-
10631. A plan shall be adopted in accordance with this chapter and 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
APPENDIX A The District's currently obtains the majority of 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
Section 5 of the 2005 Urban Water Management Plan sources,including:
• Availability of Ground Water. Prepared for the Truckee Donner Public Utility District by
Hydro-Search hic. 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 I, Martis Valley Ground-Water Basin, Basin
No_6-67,Nevada and Placer Counties. Prepared for the Truckee Donner Public Utility
District by flydro-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 INIARTIS 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
Page 5-1
i
Section 5 Water Supply Sources
ofl- m g FEET 9 N o
Local water resources are adequate to meet projected buildout conditions. Therefore, the
VU) importation of water from other areas, water transfers and water exchanges have not been
0 g investigated since they are unnecessary. Similarly,the use of desalinated water has not been
Q N N investigated,considering that the Truckee area is about 200 miles from the ocean,the use of
r— desalination is considered extremely unpractical.
3 vs i
EXISTING PRODUCTION CAPACITY IN RELATION TO PROJECTED DEMANDS
O
Zr CO 8 I LU Current maximum day potable water demand is 12.61 mgd. it is anticipated that this maximum
j day demand will increase to 15.9 mgd and 21.38 mgd by the years 2010 and 2020.respectively.
A
coAverage day water demand will increase from 6.64 mgd currently to 8.2$mgd in the year 2010
Z W CD LL LL and 11.14 mgd in the year 2020. The anticipated growth in potable water demand is presented in
Q Zi E Table 5-1 and is also shown graphically in Figure 5-2.
i r`n E'
The District currently operates twelve potable water wells in the Truckee area and one in the
0) Hirschdale area. The total capacity of these wells is about 9,550 gpm. As shown in Table 5-1.
U. ( In. i the overall system production capacity is adequate for 2005,even with removal of the Donner
Lake Intake and Greenpoint Springs from potable water service. However,adequate capacity
O does not exist to serve projected demands in 2006 with a projected maximum day demand of
Z 13.7 mgd compared with a production capacity of 13.3 mgd. Currently,there is insufficient firm
capacity,since a failure of Airport Well would leave a production capacity of only 10.4 mgd.
0
t- to
IMPACT OF UPCOMING WATER QUALITY REGULATIONS
The Environmental Protection Agency(EPA)has promulgated new regulations regarding arsenic
uJ
in drinking water supplies. New regulations regarding radon levels in drinking water are
o? anticipated in the near future. Both of these constituents are present in the existing wells at
rn 3 levels below the existing maximums.
UJ o Arsenic Regulations
Z _ r� The new arsenic regulations set a maximum level of 10 mg/1-and will become effective on
Z y rn January 1,2006. Table 5-2 gives a summary of the arsenic levels in the existing wells based on
O the most recent test results. As shown by the data,the Hirschdale and Northside Wells will
exceed the proposed arsenic limit. Two methods have been identified to bring these sources into
a «' � compliance with the proposed arsenic level_
One method involves the installation of arsenic treatment systems at the affected wells. These
systems utilize either a coagulation/filtration or ion exchange process. Both processes arc quite
expensive with capital costs estimated at over$600 per gpm of well capacity. Operations and
$ maintenance is also quite costly,estimated at$0.10 per thousand gallons produced.
! t° Y 0) The second method is known as"Avoidance." A given well would be removed from service
�`!` temporarily for testing. The testing will involve isolating a section of the aquifer by sealing off
the casing above and below this level. Water quality samples would then be taken from this
section and tested for arsenic. This process would be repeated for all water bearing strata within
A m ao the aquifer. Once the formations containing high levels of arsenic have been identified,the well
150 o casing would be sealed through these formations to prevent the entrance of water containing high
fi g levels of arsenic.
CD
w
p
N SN313YV Page 5-5
Section 5-Water Supply Sources _ _ _ f Section 5-Water Supply Sources
Table 5-2. Groundwater Well Arsenic and Radon Levels The second method is a Multimedia Mitigation Program proposed by EPA. The Multimedia
Name Arsenic Level,uvJL Radon Level,pC IL Mitigation Program addresses both water and air quality at the point of use.This program has a
A Well Not Detectable 540 limited involvement by the water provider and is focused mainly on air quality. No cost
Airport 10 1,600 estimates are available at this time,but it is anticipated that the Multimedia Mitigation Program
Glenshire Drive 10 765 costs will be substantially lower than the cost of treatment by aeration.Therefore,it is expected
Hirschdale 26 570 that the forthcoming radon regulations will have a minimal impact on the District's water supply.
Martis Valley Well No.1 9.8 Data Not Available
Northside 38 990
Prosser Annex Not Detectable 740 Available Water Production Capacity Considering Water Quality Regulations
Prosser Heights Not Detectable Not Detectable As noted above,the District will be removing the Donner Lake Intake and Greenpoint Springs
Prosser Village 7 560 from potable water service during the Summer of 2005. The capacity of Northside Well may
Sanders 4 1050 also be reduced due the new arsenic regulations. Table 5-3 gives the anticipated water
Southside No.2 Not Detectable 885 production capacity utilizing existing facilities after considering the impact of both the upcoming
Well No.20 Not Detectable 293 arsenic and radon regulations.
Arsenic data taken from Truckee Water System 2003 Water Qualm,Report
Radon data taken from testing performed in November 1999 Table 5-3. Available Water Production apacity Consi ring Water Quality Re ulations
Name Year 2004 Total Year 2004 Firm Year 2006 Total Year 2006 Firm
During the Summer of 2005,the District will be conducting pilot plant studies to determine the Capacity, m Capacity, m Capacky,gpm Capacity, m
feasibility and cost associated with arsenic removal at the Northside Well. If treatment proves A Well 150 150 150 150
cost effective,the District will be able to utilize the 810 gpm capacity into the future. If an Airport 2,000 0 2,000 0
Avoidance methodology is necessary,it is expected that the capacity of Northside Well will be Donner Lake Intake 1,400 1,400 0a 0a
reduced to 500 gpm. Glenshire Drive 1,800 1,800 1,800 1,800
Greenpoint Springs 100 too 0a 0a
Martis Valley Well No.1 1,725 1,725 1.725 1,725
The 26 mg/L level for the Hirschdale Well given in Table 5-2 was determined from samples Northside 810 810 soon Soon
taken at the wellhead. The Hirschdale Well is equipped with a pressure filter system for iron and Prosser Annex 400 400 400 400
manganese removal. Currently,finished water served to customers in the Hirschdale area has an Prosser Heights 350 350 350 350
arsenic level of 22 mg/L. During 2005,the District will be conducting pilot studies to determine Prosser Village 1,200 1,200 1.200 1,200
if the existing treatment process can be modified to remove arsenic. The District has also Sanders 300 300 300 300
t initiated discussions with the party that owns the parcel of land between the Hirschdale water Southside No.2 225 225 225 225
1 Well No.20 560 1 560 1 560 560
system and the Glenshire subdivision. The purpose of these discussions is to obtain an easement Total,gpm 1 t,o2o 9,020 9.2to 7.zto
for a pipeline that would connect the two water systems and provide the Hirschdale area with a Total,mgd 15.9 13.0 13.3 10A
new water supply without the need for treatment. Note: The Hirschdale Well is omitted since it is part of an independent system and cannot be used to serve
demands in the Truckee System
Radon Regulations a Surface water source to be removed from service during 2005
Preliminary announcements from USEPA have indicated that the maximum allowable radon n Assumed capacity reduction using the"Avoidance"Method
level will likely be reduced from 4,000 picocuries per liter(pCi/L)to 300 pCi/L. Table 5-2 also
gives a summary of the radon level in the existing wells based on the most recent test results.As
shown by the data,all of the wells will exceed the proposed radon limit.The proposed radon ADDITIONAL WATER PRODUCTION CAPACITY
level limit is under review and may be set a level higher than 300 pCi/L. Two methods have The currently available production capacity will be unable to meet projected maximum day
been identified to address the proposed reduction in the allowable radon level. demands in the year 2006. With the projected Buildout maximum day demand of 25.46 mgd,an
additional 15.2 mgd of production capacity is needed to meet buildout demands and to provide
One method involves the removal of radon in the water by aeration.Treatment by aeration would adequate firm capacity to the system.
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 Based on the 13.3 mgd of total available capacity,an additional 12.2 mgd of production capacity
operations and maintenance costs.Capital costs range from$100,000 to$150,000 for each well is needed over the next 22 years to meet projected demands. Furthermore,an additional 2.9 mgd
site.Operation and maintenance costs are estimated at$0.05 per thousand gallons. 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:
'----- Page 5-8 Page 5-9
i
Section 5-Water Supply Sources
In 2002 and 2003,the District drilled a number of exploration wells in order to identify locations
for future groundwater wells. Exploratory wells were drilled at the locations given in Figure 5-
( N 4. As a result of this exploration well program,the District acquired four well sites. The Prosser
Village Well was constructed in 2004. In 2005, the District will begin construction of the
Featherstone Well with the goal of having the well available for use in 2006. Property rights to
N ° two other sites(Fibreboard&Prosser Dam Road)have been secured by the District and will be
used to construct new wells in 2007 and 2009. The District has also identified other potential
c E wells sites and will be drilling additional test wells once property rights can be secured.
o
r N
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
o. \ redevelopment of existing wells may be necessary to maintain an adequate water supply. Of
particular concern is the long-tenn 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
o ? N of this offset,the well shaft experiences accelerated wear and it is expected that the well pump
t will need replacement every four years.
a The use of surface water,either through a treatment plant or wells with filtration,requires that a
m number of legal and environmental issues be investigated and addressed. Surface water should
o be considered along-terns water supply option and may prove to be more cost-effective than new
Q N wells as demand approaches buildout conditions. It is recommended that the use of surface
o water be investigated further towards the goals of potentially supplying new demand in the
CL period of 2010 and beyond.
rn A
� m
1 V l
I C
E
o S
N
L O d
m
3 °
a o
c E
CL E is (L
N
a 1°
Q co n p m Co n
.9 � O E � 0 U
t� zi E c c ?
O , —iu �+
L > > Co v .a < a � � � °C.i 1
m c 2 a a Y or
3 ' `,g E'
2.) I U. S tL F LL
M N N ems- O to O
polo'puetuea
Page 5-13
Section 5--Water Supply Sources Section 5 Water Supply Sources
• Construct additional wells not requiring filtration Table 54. Recommended Water Production Improvements
• Construct additional wells requiring filtration Total
• Construct a surface water treatment facility Maximum Day Production Firm Production
Year Demand,m d Capacity,m d Capacity,m d Notes
Historically,the District has used groundwater as its sole source of supply. Construction of a 1990 6.47 6.9 3.6
surface water treatment plant was undertaken by a developer in the earlier 1970s,but was halted 1991 6.88 6.9 3.6
due to political issues and questions regarding the status of water rights. It is recommended that 1992 5.83 6.9 3.6
groundwater continue to be the main source of supply. 1993 6.63 6-9 3.6
1994 6.78 6.9 3.6
Based the studies cited at the beginning of this Section,the additional groundwater wells can be 1995 5.78 7.6 4.3 Prosser Annex Well Completed
constructed without exceeding the sustainable yield of the groundwater basin. Construction of 1996 6.49 7.6 4.3
new wells is expected to be the short-term solution to increaser water supply. As development 199 6.64 8. 4.3
p g PP y' p 1998 7.22 .2 4.9 Glenshire Drive Well Completed
occurs in adjoining areas of the Martis Valley,the overall withdrawals from the basin will need 1999 7.63 8.2 4.9
to be balanced with the sustainable yield. The District has held discussions with Placer County 2000 8.58 8.6 5.3 Donner Creek Well Capacity Upgrade
Water Agency regarding long-term water supply issues in the Martis Valley. Both agencies have Niartis Valley Well No.1 constructed
agreed that further studies of the basin are necessary,along with an accounting of expected 2001 8,60 10.0 6.7 Donner Creek Well removed from potable
buildout demand versus supply for all groundwater users. water service
2002 11.47 14.6 11.7 Includes DLWS and GWS Demands and
Supply
The other two water supply options require additional investigations of legal and regulatory
Small D[,WS and GWS Wells removed
issues. A draft plan governing the use of surface water in the Truckee River basin has been 2003 11.50 15.0 12.1 from potable water service .
developed and is entitled the"Truckee River Operating Agreement." The use of surface water is Glenshire Drive Well capacity increased
subject to this plan and requires the acquisition of surface water rights. 2004 12.61 16.7 13.8 Prosser Village Well constructed
2005 13.16 13.8 10.4 Donner Lake Intake and Greenpoint
RECOMMENDED IMPROVEMENTS Springs removed from service.
New 1,5110 gpm Well Constructed
Based on the expected increase in water demand and the impact of forthcoming water quality 2006 13.71 15.4 12.5 (Featherstone Site).Northside Well
regulations, a number of water production improvements are recommended. These capacity reduced to 500 gpm
improvements are listed in Table 5-4. In the short-term,construction of new wells not requiring New 1,500 gpm Well Constructed
i p q g 2007 14.26 17.6 14.7 (Fibreboard Site)
filtration is the most reasonable alternatives to pursue. For the purposes of water supply 2008 14 80 17.6 14.7
planning,it is assumed that new wells will have a capacity of 1,500 gpm. If the capacity of new New 1.500 gpm Well Constructed
wells differs significantly from this 1,500 gpm value,the recommendations given herein should 2009 15.35 19.7 16.9 (Prosser Dam Road Site)
be adjusted accordingly. 2010 15.90 19.7 16.9
2011 16.45 193 16.9
With the impending reduction in water production capacity, it is necessary that the District 2012 17.00 21.9 19.0 New 1,500 gpm Well Constructed
aggressively pursue construction of two wells immediately to ensure that adequate capacity is 2013 17.54 21.9 19.0
available to serve customer demands. Construction of a third well is necessary to provide 2014 18.09 21.9 19.0
adequate firm capacity in the event that a single well is out of service for any length of time 2015 18-(A 21.9 19.02016 19.19 24.1 21.2 New 1,500 gpm Well Constructed
during high-demand periods. 2017 M74 24.1 21.2
2018 20.28 24.1 21.2
The proposed phasing given in Table 5-4 is based on anticipated growth in demand throughout 2019 20.83 24.1 21.2
the service area. An additional four wells will be needed to serve buildout conditions and should 2020 21.38 26.2 23.3 New 1,500 gpm Well Constructed
be constructed as growth and increases in water demand dictate. Figure 5-3 gives the 2021 21.93 26.2 23.3
relationship of projected demand to the recommended water supply improvements. 2022 22.48 26.2 23.3
2023 23.02 26.2 23-3
2024 23.57 28.4 25.5 New 1,500 gpm Well Constructed
2025 24.12 28.4 25.5
2026 1 24.67 28.4 25.5
Buildout 25.46 28.4 25.5-
Page 5-10 Page 5-11
Section 5-Water Supply Sources
Table 5-1. historic and Projected Potable Water Demand
Available LO
Average Day Maximum Day Production Notes l c
Year Demand,an d Demand,an d Capacity,an d \ N
1990 2.89 6.47 6.9
1991 3.07 6.88 6.9
to �
1992 2.61 5.83 6.9 N
1993 2.81 6.63 6.9 N
1994 3.28 6.78 6.9 C \ N
1995 3.10 5.78 7.6 Prosser Annex Well Completed , N
1996 3.47 6.49 7.6 j
1997 3.52 6.64 7.6
1998 3.47 7.22 8.2 Glenshire Drive Well Completed A
1999 4.08 7.63 8.2 t
2000 4.29 8.58 8-6 Donner Creek Well Capacity Upgrade U ,n
Maros Valley Well No.1 constructed 00 t E N
2001 4.65 8.60 10.0 Donner Creek Well removed from potable water � F
service v E
2002 6.09 11.47 14.6 Includes DLWS and GWS Demands and Supply M i
Small DIMS and GWS Wells removed from 2 �
2003 6.05 11.50 15.0 potable water service L
Gienshire Drive Well capacity increased 01
O o
2004 6.57 12.61 16.7' Prosser Village Well constructed
Donner Lake Intake and GreenP°int Springs
N
2W5 6.85 13.16 13.8a removed from potable water service W € `
2006 7.14 13.71 13.3 Northside Well capacity reduced to 500 gpm
2007 7.42 14.26 13.3 > y
2008 7.71 14.80 13.3 C
t
t 2009 8.00 15.35 13.3 IQ
2010 8.28 1590 13.3 E o c
2011 8.57 16.45 13.3 18c \ N
0
2012 8.85 17.00 13.3 Q
2013 9,14 17.54 13.3 o m a
c
2014 9.42 18.09 13.3 �+ a c c
20I5 9.71 18.64 13.3 Q !, @ r E
10
2016 9.99 19.19 13.3 E am o
2017 10.28 19.74 13.3 O C, a- 11 o
2018 10.56 20.28 13.3 0 O t]U a
2019 10.85 20.83 13.3 .0 a)0 E E
2020 11.14 21.38 13.3 u a' E .21
2021 11.42 21.93 13.3 > m x '
2022 11.71 22.48 13.3 a o a o
2023 11.99 23.02 13-3 m•2 2 tL a
, o
2024 12.28 23.57 13.3 N V;in � u,
2
2025 12.56 24.12 13.3 tt_Mto 9 ti
� l 2026 12._85--- ---24.67 13.3
Buddout 13.05 1 25.46 13.3 101
0 0 o a o 0 0 •-
O in O to C Ln C
M N N - �-
p6tu`pueuteO
Page 5-6 --- ------
Section 5 Water Supply Sources Section 5--Water Supply Sources
the MVGB has improved over the years,the estimates of available water have been refined and RELIABILITY OF WATER SUPPLY
therefore,the most recent studies are considered to have the best information regarding water Currently,the major producers of water in the MVGB are the District,the Placer County Water
availability. Agency(Lahontan Subdivision),Donner Creek Mobile Home Park,Ponderosa Golf Course,and
Teichert Aggregates. There are numerous small wells supporting individual residences along
The 1975 study by Hydro-Search estimated annual recharge to the MVGB at 18,200 AFY with a with some other uses such as the Martis Creek Campground. Total basin-wide withdrawals for
total subsurface storage volume of 1,050,000 acre-feet. The 1975 study also concluded that the year 2000 were estimated 7,262 AFY.
y 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, For 2004, withdrawals from the MVGB by the District totaled 7,109 AF for potable water
a new evaluation of groundwater availability was not conducted as part of those efforts. purposes and an additional 276 AF for irrigation and construction water purposes. An additional
335 AF of surface water was used by the District in the Donner Lake area. Total withdrawals
The 2001 study represented the first reconsideration of the MVGB water availability since the from the basin are estimated at about 8,905 AFY for the year 2004.
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 additional 5,433 AFY is recharged to the Buildout average day potable water demand for the District is projected at 13.05 mgd.
upper layer of the MVGB by the Tahoe-Truckee Sanitation Agency's (TTSA) wastewater Therefore,a sustainable water supply about 14,619 AFY will be required to meet this buildout
treatment plant. This 2001 study concluded that the sustainable yield of the MVGB is 24,000 condition. An additional 261 AFY(85 million gallons annually)will be needed to serve non-
AFY. potable water demands for a total of 14,880 AFY.
In 2002,a study entitled Independent Appraisal of Martis Valley Ground Water Availability, In May 2001, a document entitled Technical Memorandum and Net Depletion for Martis
Nevada and Placer Counties was conducted by Kennedy/Jenks Consultants. This study agreed Valley Groundwater Basin prepared by David Antonucci estimated buildout water demand for
with the sustainable yield estimate of 24,000 AFY by Nimbus Engineers in 2001. The all water producers throughout the MVGB at 20,936 AFY. This document projected a buildout
Kennedy/Jenks study also concluded that the 24,000 AFY likely underestimates the amount of demand of 13,326 AFY for areas currently served by the District, with 7,610 AFY for areas
water available on a sustainable basis since the 2001 Nimbus study underestimated both basin currently served by other agencies or individual wells. Assuming the 7,610 AFY estimate for
recharge and ground water discharge to tributary streams. other parties is correct,a total of 22,490 AFY is needed to serve the entire region.
In April 2003,a study conducted by InterFlow Hydrology and Cordilleran Hydrology entitled With a total water supply of at least 24,000 AFY,there is adequate water supply to meet the
Measurement of Ground Water Discharge to Streams Tributary to the Truckee River in Martis projected buildout conditions. There are 484,000 acre-feet of water in storage in the MVGB.
Valley,Nevada and Placer Counties,California examined the issue of ground water discharge The projected total demand of 22,490 AFY at buildout is equal to less than five percent of the
to tributary streams and concluded that about 34,000 AFY of water is available on a sustainable capacity of the MVGB and there is adequate water to provide for over 20 years worth of demand
€ basis. even if no recharge of the basin were to occur.
The California Department of Water Resources has not determined that the MVGB is being The great majority of groundwater basin recharge results from snowfall and snow-melt during the
overdrafted and there are not any known instances of contamination of the MVGB. The MVGB winter period. Summer thunderstorms can produce high intensity rainfall events of short
is currently unadjudicated and none of the groundwater users has expressed a desire to have the duration. However, these storms do not make a significant contribution to basin recharge.
basin adjudicated to date. Therefore,it is reasonable to assume that,at a minimum,the 24,000 Figure 5-1 shows historic snowfall and snowpack data at Donner Summit for the period of 1879-
AFY of water cited in the Nimbus study is available to support development in Truckee and the 2005 as measured by the Central Sierra Snow Laboratory. As shown in this graph snowfall(and
surrounding areas. 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
DONNER LAKE SURFACE WATER SUPPLY AND GREENPOINT SPRINGS snowfall occurred in 1924-1926 with a total of about 54 feet. Considering the large amount of
As described in Section 3,the District currently operates two surface water sources that provide water in storage in relation to the projected buildout demand,one year(or even multiple years)
water to the Donner Lake area:an Intake Pump Station with a capacity of 1,400 gpm and the of below average precipitation and basin recharge does not have a significant impact upon the
Greenpoint Springs with a capacity between 100 and 300 gpm. These facilities will be removed water supply. Therefore,the 24,000 AFY noted above is considered the 3-year minimum water
from service permanently during the Summer of 2005 and the District will discontinue using supply.
these surface water supplies at that time.
Page 5-2
Page>-i
AFY and sufficient water exists to supply the overall project. However,the land use analysis has
HISTORIC WATER DEMAND not been updated to confirm this inference.
The District currently operates twelve wells to provide potable water to water system customers.
Surface water is not used at this time. Two additional wells are used to serve non-potable CONCLUSIONS
demands. Table 2 gives a listing of groundwater withdrawals for the past five years. All of these The District can commit to serving up to 152.5 AFY at this time. Therefore there are two
wells utilize water from the Martis Valley Groundwater Basin(MVGB). options available regarding the project:
Table 2. Historic Groundwater Withdrawals,2003-2007 1) Scale back the overall project such that demand will not exceed 152.5 AFY,
Year Potable Water Non-Potable Water Total
(Acre-feet) _ (Acre-feet) (Acre-feet) 2) Construct the project in phases. Under this approach,the first phase could not exceed
2003 6,777 223 9,003 152.5 AFY. In order for additional development to proceed,a new land use analysis
2004 7,438 276 9,718 and calculation of buildout water demand would need to be performed to ensure that
2005 6,846 220 9,071 the District could serve the additional development within the 14,619 AFY of
2006 7,277 259 9,542 confirmed water supply.
2007 7,469 1 291 9,767
If the new land use analysis determines that buildout water demand will exceed
14,619 AFY, the developer will be required to fund additional studies regarding
AVAILABILITY AND RELIABILITY OF WATER SUPPLIES identification of additional water supplies and/or construct facilities necessary to
It is expected that all current and future demands will be supplied by groundwater from the utilize the additional water supplies.
Martis Valley Groundwater Basin(MVGB). However,the District holds some surface water
rights and retains the right to utilize surface water should it prove advantageous to the District.
The MVGB is unadjudicated and is not being overdrafted. Section 5 of the UWMP gives a
detailed discussion of the MVGB along with the quantity and reliability of the water supply. The
UWMP concluded that there is a minimum supply of 24,000 AFY available from the MVGB,
even during multiple dry-year periods.
The UWMP projects an annual potable water demand of 14,619 AFY at buildout. An additional
261 AFY of non-potable water demand is also expected for a District-wide total of 14,880 AFY.
Based on a demand of 7,610 AFY for other water users in the area,total water demands in the
MVGB at buildout will be 22,744 AFY.
Section 5 of the UWMP is included in Appendix A for reference. The reader is referred to the
complete UWMP for additional information,if desired.
IMPACT OF THE RAILYARD MASTER PLAN PROJECT
As noted above,the District has project potable water demand at buildout to be 14,619 AFY. Of
that total, 152.5 AFY was assumed for the Railyard Master Plan.However,the current project
will require 406.2 AFY for a difference of about 254 AFY. The land use analysis that
determined that 14,619 AFY value was performed in 2002 and was based upon anticipated
maximum development.
Since 2002,a number of projects have been approved and constructed. In many cases,the actual
approved project consisted of a lesser level of development than the maximum allowable
development. As such,the District's ultimate buildout water demand is likely less than 14,619