HomeMy WebLinkAbout12 Truckee Railyard Master Plan Project Agenda Item # 12
TRUCKEE
DONNER
Public Utility Distrtct 'I
Workshop
To: Board of Directors
From: Neil Kaufman
Date: May 21, 2008
Subject: Water Supply Assessment for the Truckee Railyard Master Plan Project
1. WHY THIS MATTER IS BEFORE THE BOARD
A Water Supply Assessment (WSA) has been prepared for the Truckee Railyard Master Plan
project. According to the California Water Code, the WSA must be approved by the District's
Board of Directors.
2. HISTORY
On March 4, 2008, the Town of Truckee requested that the District prepare a WSA fort e
The
proposed Truckee Railyard Master Plan project. project The general locateon of the projedevelopment �t is
property located on the eastern end of downtown Truckee.
shown in Figure 1. as a location f
uture
The District's 2004 Water Master Plan identifiedthe the project
site at that time An ave�agfe day
development. Detailed plans had not been prepared ected based upon 34.04 acres at 4,000
water demand of 136,160 gallons per day (gpd) was pro j
gallons per acre per day. That projected demand was then incorporated into the District's 2005
Urban Water Management Plan (UWMP).
3. NEW INFORMATION
The owner of the property has created a more detailed redevelopment plan. The project
currently consists of:
A 60 room hotel;
A 1,000 seat movie theater;
70,000 square feet of retail space;
• 545 residential units in some form of multi-family/condo/attached housing;
25 single family residential units;
15,000 square feet of office space;
A 20,000 square feet grocery store; and
25,000 square feet of civic use space.
Based upon this development, an average day demand of 362,640 gpd is now expected.
According to the California Water Code, a WSA must be prepared for any project that consists
of any of the following:
• A proposed residential development of more than 500 dwelling units
• A proposed shopping center or business
establishment
floor et space
employing more than 1,000
persons or having more than 500,000 squarefeet
• A proposed commercial office building employing more than 1,000 persons or having more
than 250,000 square feet of floor space
• A proposed hotel or motel, or both, having more than 500 rooms
• A proposed industrial, manufacturing, or processing plant
40 acres ofsland,trial por having more
ark planned to
house more than 1,000 persons, occupying more than
than 650,000 square feet of floor area
• A mixed-use project that includes one or amount
o o fw projects specified
water equivalent to, or greaterbdivision tthan, the
• A project that would demand an amount
amount of water required by a 500 dwelling unit project
Considering that the Truckee Railyard Master PIan project ornia 'Watee Code outanetthe process Sor
is required. Sections 10910 to 10914 of the Ca
preparing a WSA and describe the information that must be Wnby ahe IDistrct'sVBoard of
component of the process requires that the WSA be approved
Director's. A copy of the draft WSA is attached and is summarized below.
The UW MP described a buildout potable water demand
this anticipated 19Abuildout demand The UWMP further
determined that sufficient water supply exists su pp
Of the 14,619 AFY total, 152.5 AFY (136,160 gpd) was assumed for the Truckee for a Raillyard e
Master Plan. However, the current project will require 406.2 AFY (362,640 gp )
that determined that 619 AFY value was
of about 254 AFY. The land use based upon analysis
antic anticipated maximum development. Since 2002, a
performed in 2002 and was
number of projects have been approved and constructed. In many cases, the actual approve
project consisted of a lesser level of develope edemand hs likely less thanthan te maximum ab4,619 le eAFY and
As such, the District's ultimate buildout wa
sufficient water exists to supply the overall project. However, the land use analysis has not
been updated to confirm this inference.
As described in the WSA, the District can commit to providing 152.5 AFY at this time. There are
two options available to the projects developer:
1) Scale back the overall project such that demand will not exceed 152.5 AFY.
2) Construct the project in phases. Under this approach, the first phase could not
exceed 152.5 AFY. In order buildoutfor additional development to proceed, a new water demand would need to be performed nd use
and
analysis and calculation of to
ensure that the District could serve the additional development within the 14,619
AFY of confirmed water supply.
exceed
If the new land use analysis determinesbe required t to fundbuildout
addi eonal studies r demand 1rlega d rig
14,619 AFY, the developer may
identification of additional water supplies and/or construct facilities necessary to
utilize the additional water supplies.
Initial conversations with the developer's representative have indicated that the developer will
pursue option 2 and will fund a new land use analysis.
4. FISCAL IMPACT
There is no direct fiscal impact to the District. Staff time spent in preparing the WSA has been
billed against the Development Agreement for the Truckee Railyard Master Plan project.
5. RECOMMENDATION:
The Board adopt the Water Supply Assessment for the Truckee Railyard Master Plan project.
Michael D. Holley, General Manager
Attachments:
Draft Water Supply Assessment
Draft Resolution
Illl[I�III IIIII�J pI11IlIIIJIIi[I� I�I IIII�NIII
M C bpi ,wl D 1 3w •
'� Yl! pY #M R
as
Public
Resolution No. 2008. XXX
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 as 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 of by the following roll call vote:
AYES:
NOES:
ABSTAIN:
TRUCKEE DONNER PUBLIC UTILITY DISTRICT
By
Tim Taylor, President
TRUCKEE
DONNER
Public titility District
�i
a'
DRAFT
TRUCKEE RAILYARD MASTER PLAN
WATER SUPPLY ASSESSMENT
ADOPTED
xxxx 2008
INTRODUCTION
This Water Supply Assessment (WSA) has been prepared by Truckee Donner Public Utility
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
• 545 residential units in some form of multi-family/condo/attached housing.
25 single family residential units
• 15,000 square feet of office space
• A 20,000 square feet grocery store
• 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
gallons per acre per day. That projected demand was then incorporated into the District's 2005
Urban Water Management Plan (UWMP).
Based upon current information, an average day demand of 362,640 gpd is now expected. A
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 362,640
HISTORIC WATER DEMAND
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
demands. Table 2 gives a listing of groundwater withdrawals for the past five years. All of these
wells utilize water from the Martis Valley Groundwater Basin (MVGB).
Table 2. Historic Groundwater Withdrawals,2003-2007
Year Potable Water Non-Potable Water Total
(Acre-feet) (Acre-feet) (Acre-feet)
2003 6,777 223 9,003
2004 7,438 276 9,718
2005 6,846 220 9,071
2006 7,277 259 9,542
2007 7,469 291 9,767
AVAILABILITY AND RELIABILITY OF WATER SUPPLIES
It is expected that all current and future demands will be supplied by groundwater from the
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
AFY and sufficient water exists to supply the overall project. However, the land use analysis has
not been updated to confirm this inference.
CONCLUSIONS
The District can commit to serving up to 152.5 AFY at this time. Therefore there are two
options available regarding the project:
1) Scale back the overall project such that demand will not exceed 152.5 AFY.
2) Construct the project in phases. Under this approach, the first phase could not exceed
152.5 AFY. In order for additional development to proceed, a new land use analysis
and calculation of buildout water demand would need to be performed to ensure that
the District could serve the additional development within the 14,619 AFY of
confirmed water supply.
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
identification of additional water supplies and/or construct facilities necessary to
utilize the additional water supplies.
APPENDIX A
Section 5 of the 2005 Urban Water Management Plan
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
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
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
Page 5-1
Section 5—Water Supply Sources
the MVGB has improved over the years, the estimates of available water have been refined and
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 additional 5,433 AFY is recharged to the
upper layer of the MVGB by the Tahoe-Truckee Sanitation Agency's (TTSA) 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 Martis
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.
DONNER LAKE SURFACE WATER SUPPLY AND GREENPOINT SPRINGS
As described in Section 3, the District currently operates two surface water sources that provide
water to the Donner Lake area: an Intake Pump Station with a capacity of 1,400 gpm and the
Greenpoint Springs with a capacity between 100 and 300 gpm. These facilities will be removed
from service permanently during the Summer of 2005 and the District will discontinue using
these surface water supplies at that time.
Page 5-2
Section 5—Water Supply Sources
RELIABILITY OF WATER SUPPLY
Currently, the major producers of water in the MVGB are the District, the Placer County Water
Agency (Lahontan Subdivision), Donner Creek Mobile Home Park, 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. Total basin-wide withdrawals for
the year 2000 were estimated 7,262 AFY.
For 2004, withdrawals from the MVGB by the District totaled 7,109 AF for potable water
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
from the basin are estimated at about 8,905 AFY for the year 2004.
Buildout average day potable water demand for the District is projected at 13.05 mgd.
Therefore, a sustainable water supply about 14,619 AFY will be required to meet this buildout
condition. An additional 261 AFY (85 million gallons annually) will be needed to serve non-
potable water demands for a total of 14,880 AFY.
In May 2001, a document entitled Technical Memorandum and Net Depletion for Martis
Valley Groundwater Basin prepared by David Antonucci estimated buildout water demand for
all water producers throughout the MVGB at 20,936 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 22,490 AFY is needed to serve the entire region.
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 22,490 AFY at buildout is equal to less than five 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-
2005 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 does not have a significant impact upon the
water supply. Therefore, the 24,000 AFY noted above is considered the 3-year minimum water
supply.
Page 5-3
University of California,Berkeley DONNER SUMMIT SNOWFALL AND SNOWPACK
Central Sierra Snow Laboratory WINTERS 1879 ' 200
PO sox 810 5 70
7
Soda Springs,California 95728 USA
_ (530)426-0318
http://research.chance.berkeley.edu/cssifindex.htm
20 Total Snowfall(measured twice/day)
Data sources Maximum Snowpack Depth 60
1879-1945,1953-1957 Southern Pacific Railroad
1946-1952,1958-2005 Central Sierra Snow Laboratory — ---
n=127
f snowfall(cm):ave=1038,std dev=342
snowpack(cm):ave=361,std dev=166
i 50
15�
w 40
w
m
I
10 30
20
5
10
l
I
0
0 - ,
l 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
WINTER
F
FIGU RE
Section 5—Water Supply Sources
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.
EXISTING PRODUCTION CAPACITY IN RELATION TO PROJECTED DEMANDS
Current maximum day potable water demand is 12.61 mgd. It is anticipated that this maximum
day demand will increase to 15.9 mgd and 21.38 mgd by the years 2010 and 2020, respectively.
Average day water demand will increase from 6.64 mgd currently to 8.28 mgd in the year 2010
and 11.14 mgd in the year 2020. The anticipated growth in potable water demand is presented in
Table 5-1 and is also shown graphically in Figure 5-2.
The District currently operates twelve potable water wells in the Truckee area and one in the
Hirschdale area. The total capacity of these wells is about 9,550 gpm. As shown in Table 5-1,
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
does not exist to serve projected demands in 2006 with a projected maximum day demand of
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.
IMPACT OF UPCOMING WATER QUALITY REGULATIONS
The Environmental Protection Agency (EPA) has promulgated new regulations regarding arsenic
in drinking water supplies. New regulations regarding radon levels in drinking water are
anticipated in the near future. Both of these constituents are present in the existing wells at
levels below the existing maximums.
Arsenic Regulations
The new arsenic regulations set a maximum level of 10 mg/L and will become effective on
January 1, 2006. Table 5-2 gives a summary of the arsenic levels in the existing wells based on
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
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 are 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.
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
the aquifer. Once the formations containing high levels of arsenic have been identified, the well
casing would be sealed through these formations to prevent the entrance of water containing high
levels of arsenic.
Page 5-5
Section 5-Water Supply Sources
Table 5-1. Historic and Projected Potable Water Demand
Available
Average Day Maximum Day Production Notes
Year Demand,an d Demand,an d Ca aci ,m d
1990 2.89 6.47 6.9
1991 3.07 6.88 6.9
1992 2.61 5.83 6.9
1993 2.81 6.63 6.9
1994 3.28 6.78 6.9
1995 3.10 5.78 7.6 Prosser Annex Well Completed
1996 3.47 6.49 7.6
1997 3.52 6.64 7.6
1998 3.47 7.22 8.2 Glenshire Drive Well Completed
1999 4.08 7.63 8.2
2000 4.29 8.58 8.6 Donner Creek Well Capacity Upgrade
Martis Valley Well No. 1 constructed
2001 4.65 8.60 10.0 Donner Creek Well removed from potable water
service
2002 6.09 11.47 14.6 Includes DLWS and GWS Demands and Supply
Small DLWS and GWS Wells removed from
2003 6.05 11.50 15.0 potable water service
Glenshire Drive Well capacity increased
2004 6.57 12.61
16.73 Prosser Village Well constructed
Donner Lake Intake and Greenpoint Springs
2005 6.85 13.16 13.8 removed from potable water service
2006 7.14 13.71 13.3 Northside Well capacity reduced to 500 gpm
2007 7.42 14.26 13.3
2008 7.71 14.80 13.3
2009 8.00 15.35 13.3
2010 8.28 15.90 13.3
2011 8.57 16.45 13.3
2012 8.85 17.00 13.3
2013 9.14 17.54 13.3
2014 9.42 18.09 13.3
2015 9.71 18.64 13.3
2016 9.99 19.19 13.3
2017 10.28 19.74 13.3
2018 10.56 20.28 13.3
2019 10.85 20.83 13.3
2020 11.14 21.38 13.3
2021 11.42 21.93 13.3
2022 11.71 22.48 13.3
2023 11.99 23.02 13.3
2024 12.28 23.57 13.3
2025 12.56 24.12 13.3
2026 12.85 24.67 13.3
Buildout 13.05 25.46 13.3
Page 5-6
Figure 5-2. Projected Potable Water Demand vs. Existing Production Capacity, 1990-2025-
30.0 -
-0 Historic Average Day Demand
Future Average Day Demand Projection
-♦--Historic Maximum Day Demand
Future Maximum Day Production Projection -
25.0 —Total Production Capacity
Firm Production capacity
20.0
= 15.0 - - - - - - - -
�a I
10.0
5.0
E i
a�
C
f -
� 0.0 � — — — — — - - - — - - - — 2010 _- — 2015 — 2020 2025
1990 1995 2000 2005
� Year
I
i
Section 5—Water Supply Sources
Table 5-2. Groundwater Well Arsenic and Radon Levels
Name Arsenic Level,u Radon Level, Ci/L
A Well Not Detectable 540
Airport 10 1,600
Glenshire Drive 10 765
Hirschdale 26 570
Martis Valley Well No. 1 9.8 Data Not Available
Northside 38 990
Prosser Annex Not Detectable 740
Prosser Heights Not Detectable Not Detectable
Prosser Village 7 560
Sanders 4 1050
Southside No. 2 Not Detectable 885
Well No. 20 Not Detectable 293
Arsenic data taken from Truckee Water System 2003 Water Quality Report
Radon data taken from testing performed in November 1999
During the Summer of 2005, the District will be conducting pilot plant studies to determine the
feasibility and cost associated with arsenic removal at the Northside Well. If treatment proves
cost effective, the District will be able to utilize the 810 gpm capacity into the future. If an
Avoidance methodology is necessary, it is expected that the capacity of Northside Well will be
reduced to 500 gpm.
The 26 mg/L level for the Hirschdale Well given in Table 5-2 was determined from samples
taken at the wellhead. The Hirschdale Well is equipped with a pressure filter system for iron and
manganese removal. Currently, finished water served to customers in the Hirschdale area has an
arsenic level of 22 mg/L. During 2005, the District will be conducting pilot studies to determine
if the existing treatment process can be modified to remove arsenic. The District has also
initiated discussions with the party that owns the parcel of land between the Hirschdale water
system and the Glenshire subdivision. The purpose of these discussions is to obtain an easement
for a pipeline that would connect the two water systems and provide the Hirschdale area with a
new water supply without the need for treatment.
Radon Regulations
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. 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
level limit is under review and may be set 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.
Page 5-8
Section 5—Water Supply Sources
The second method is a Multimedia Mitigation Program proposed by EPA. 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.
Available Water Production Capacity Considering Water Quality Regulations
As noted above, the District will be removing the Donner Lake Intake and Greenpoint Springs
from potable water service during the Summer of 2005. The capacity of Northside Well may
also be reduced due the new arsenic regulations. Table 5-3 gives the anticipated water
production capacity utilizing existing facilities after considering the impact of both the upcoming
arsenic and radon regulations.
Table 5-3. Available Water Production Capacity Considering Water Quality Re ulations
Name Year 2004 Total Year 2004 Firm Year 2006 Total I Year 2006 Firm
Capacity, m Capacity, m Ca acit ,g m Ca acit , m
A Well 150 150 150 150
Airport 2,000 0 2,000 0
Donner Lake Intake 1,400 1,400 Oa Oa
Glenshire Drive 1,800 1,800 1,800 1,800
Greenpoint Springs 100 100 0a Oa
Martis Valley Well No. 1 1,725 1,725 1,725 1,725
Northside 810 810 500b 500b
Prosser Annex 400 400 400 400
Prosser Heights 350 350 350 350
Prosser Village 1,200 1,200 1,200 1,200
Sanders 300 300 300 300
Southside No. 2 225 225 225 225
Well No.204 560 560 560 560
Total,gpm 11,020 9,020 9,210 7,210
Total,mgd 15.9 13.0 13.3 10.4
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
a Surface water source to be removed from service during 2005
b Assumed capacity reduction using the"Avoidance"Method
ADDITIONAL WATER PRODUCTION CAPACITY
The currently available production capacity will be unable to meet projected maximum day
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
adequate firm capacity to the system.
Based on the 13.3 mgd of total available capacity, an additional 12.2 mgd of production capacity
is needed over the next 22 years to meet projected demands. Furthermore, an additional 2.9 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:
Page 5-9
Section 5—Water Supply Sources
• 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 was undertaken by a developer in the earlier 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 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 short-term solution to increasing water supply. As 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 District has held discussions with Placer County
Water Agency regarding long-term water supply issues in the Martis Valley. Both agencies have
agreed that further studies of the basin are necessary, along with an accounting of expected
buildout demand versus supply for all groundwater users.
The other two water supply options require additional investigations of legal and regulatory
issues. A draft plan governing the use of surface water in the Truckee River basin has been
developed and is entitled the "Truckee River Operating Agreement." The use of surface water is
subject to this plan and requires the acquisition of surface water rights.
RECOMMENDED IMPROVEMENTS
Based on the expected increase in water demand and the impact of forthcoming water quality
regulations, a number of water production improvements are recommended. These
improvements are listed in Table 5-4. In the short-term, construction of new wells not requiring
filtration is the most reasonable alternatives to pursue. For the purposes of water supply
planning, it is assumed that new wells will have a capacity of 1,500 gpm. If the capacity of new
wells differs significantly from this 1,500 gpm value, the recommendations given herein should
be adjusted accordingly.
With the impending reduction in water production capacity, it is necessary that the District
aggressively pursue construction of two wells immediately to ensure that adequate capacity is
available to serve customer demands. Construction of a third well is necessary to provide
adequate firm capacity in the event that a single well is out of service for any length of time
during high-demand periods.
The proposed phasing given in Table 5-4 is based on anticipated growth in demand throughout
the service area. An additional four wells will be needed to serve buildout conditions and should
be constructed as growth and increases in water demand dictate. Figure 5-3 gives the
relationship of projected demand to the recommended water supply improvements.
Page 5-10
Section 5-Water Supply Sources
Table 5-4. Recommended Water Production Improvements
Total
Maximum Day Production Firm Production
7Year Demand,m d Ca aci ,m d Capacity, m d Notes
0 6.47 6.9 3.6
1991 6.88 6.9 3.6
1992 5.83 6.9 3.6
1993 6.63 6.9 3.6
1994 6.78 6.9 3.6
1995 5.78 7.6 4.3 Prosser Annex Well Completed
1996 6.49 7.6 4.3
1997 6.64 7.6 4.3
1998 7.22 8.2 4.9 Glenshire Drive Well Completed
1999 7.63 8.2 4.9
2000 8.58 8.6 5.3 Donner Creek Well Capacity Upgrade
Martis Valley Well No. 1 constructed
2001 8.60 10.0 6.7 Donner Creek Well removed from potable
water service
Includes DLWS and GWS Demands and
2002 11.47 14.6 11.7 Supply
Small DLWS and GWS Wells removed
2003 11.50 15.0 12.1 from potable water service
Glenshire Drive Well capacity increased
2004 12.61 16.7 13.8 Prosser Village Well constructed
10.4 Donner Lake Intake and Greenpoint
2005 13.16 13.8 Springs removed from service.
New 1,500 gpm Well Constructed
2006 13.71 15.4 12.5 (Feaercapacitys tone Site). e Well
reduced to 00 gpm
14.7 New 1,500 gpm Well Constructed
2007 14.26 17.6 (Fibreboard Site)
2008 14.80 17.6 14.7
New 1,500 gpm Well Constructed
2009 15.35 19.7 16.9 (Prosser Dam Road Site)
2010 15.90 19.7 16.9
2011 16.45 19.7 16.9
2012 17.00 21.9 19.0 New 1,500 gpm Well Constructed
2013 17.54 21.9 19.0
2014 18.09 21.9 19.0
2015 18.64 21.9 19.0
2016 19.19 24.1 21.2 New 1,500 gpm Well Constructed
2017 19.74 24.1 21.2
2018 20.28 24.1 21.2
2019 20.83 24.1 21.2
2020 21.38 26.2 23.3 New 1,500 gpm Well Constructed
2021 21.93 26.2 23.3
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
Uil
26 24.67 28.4 25.5
dout 25.46 28.4 25.5
Page 5-11
Figure 5.3. Projected Potable Water Demand vs. Proposed Production Capacity, 1990-2025—
30.0
t Historic Average Day Demand
Future Average Day Demand Projection
0 Historic Maximum Day Demand
25.0 Future Maximum Day Production Projection -- - -- - - - - -
Total Production Capacity
Firm Production Capacity
20.0rt -- - - - - -
V
rn
15.0 1 - - -- - -- - -- - -- - -- - -
d
- - -- - - -
10.0 rt -- - -- - - - - - -
-- - - -- -
5.0 + -- - -- - - -- - - -
0.0 -' 2000 2005 2010 — —
2015 2020 2025
1990 1995
Year
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-
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
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
wells sites and will be drilling additional test wells once property rights can be secured.
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 it is expected that the well pump
will need replacement every four years.
The use of surface water, either through a treatment plant or wells with filtration, requires that a
number of 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. It is recommended that the use of surface
water be investigated further towards the goals of potentially supplying new demand in the
period of 2010 and beyond.
Page 5-13