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Appendix F_WSA
APPENDIX F WATER SUPPLY ASSESMENT Agenda Item # 10 TRUCKEE DONNER Public Utility District ACTION To: Board of Directors From: Neil Kaufman Date: September 03, 2008 Subject: Revision to Railyard Water Supply Assessment 1. WHY THIS MATTER IS BEFORE THE BOARD A revised 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 for the proposed Truckee Railyard Master Plan project. The project involves the redevelopment of a property located on the eastern end of downtown Truckee. The general location of the project is shown in Figure 1. The District's 2004 Water Master Plan (WMP) 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). The owner of the property has created a more detailed redevelopment plan that is under review by the Town. An average day demand of 362,640 gpd (406 AFY) is currently expected for the project. Based upon that demand, the Water Department prepared a WSA for the project that was reviewed and adopted by the Board of Directors on May 21, 2008. The WSA noted that the District could commit to providing 152.5 AFY at that time and described two options available to the project's developer: 1) Scale back the overall project such that demand will not exceed 152.5 AFY. 2) Construct the project in phases. 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. 3. NEW INFORMATION The developer of the project opted to have a new land use analysis performed and Acumen Engineering was retained to perform the study. Acumen Engineering identified 42 large parcels that have been developed since the preparation of the WMP. In most cases, the actual approved project consisted of a lesser level of development than the maximum allowable development assumed in WMP. In total, the projected water demand for the approved projects is 1,301 AFY as opposed to an assumed demand of 1,859 AFY. This represents a difference of 558 AFY. Based upon the analysis by Acumen Engineering, buildout water demand for the District is now projected to be 14,061 AFY. Compared to a confirmed water supply of 14,619 AFY, there is 558 AFY available to serve additional development. The Railyard Master Plan project requires an additional 254 AFY to serve the project at buildout and the District has sufficient water supply reserves to meet this demand. A revised WSA has been prepared for the Railyard Master Plan project based upon this new information and is attached for review. Attachments: Draft Revised Water Supply Assessment Draft Resolution 4. FISCAL IMPACT There is no direct fiscal impact to the District. Staff time spent in preparing the revised WSA has been billed against the Development Agreement for the Truckee Railyard Master Plan project. 5. RECOMMENDATION Adopt the Revised Water Supply Assessment for the Truckee Railyard Master Plan project. Ed Taylor Water Utility Manager Michael D. Holley General Manager TRUCKEE RAILYARD MASTER PLAN WATER SUPPLY ASSESSMENT REVISED September 3, 2008 THIS DOCUMENT SUPERSEDES THE WATER SUPPLY ASSESSMENT ADOPTED ON MAY 21, 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 Railvard 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 (Acre-feet) Non -Potable Water (Acre-feet) Total (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. In August of 2008, an engineering study was conducted by Acumen Engineering to update the 2002 land use analysis. A copy of that study is included in Appendix B. Acumen identified 42 large parcels that have been developed in the intervening period. In most cases, the actual approved project consisted of a lesser level of development than the maximum allowable development assumed in the 2002 analysis. In total, the projected water demand for the approved projects is 1,301 AFY as opposed to an assumed demand of 1,859 AFY calculated in the 2002 analysis. This represents a difference of 558 AFY. CONCLUSIONS Based upon the analysis by Acumen Engineering, buildout water demand for the District is now projected to be 14,061 AFY. Compared to a confirmed water supply of 14,619 AFY, there is 558 AFY available to serve additional development. The Railyard Master Plan project requires an additional 254 AFY to serve the project at buildout. The District has sufficient water supply reserves to meet this demand. Q Q� 4 TRUCKEE DONNER Public Utility District General Location of Railyard Master Plan Project 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 Califomia, Berkeley Central Sierra Snow Laboratory PO Box 810 Soda Springs, Califomia 95728 USA (530) 426-0318 http://rese arch.chance .berkel ey.edu/cssUnd ex.htm 20 15 fn Iz w l — w 2 10 5 0 1880 DONNER SUMMIT SNOWFALL AND SNOWPACK WINTERS 1879 - 2005 1890 1900 1910 1920 Data Sourc es 1879-1945, 1953-1957 Southem Pacific Railroad 1946-1952, 1958-2005 Central Sierra Snow Laboratory n = 127 snowfall (cm): ave =1038, std dev = 342 snowpack (cm): ave = 361, std dev = 166 1930 1940 1950 1960 WINTER Total Snowfall (measured twice/day) ® Maximum Snowpack Depth 1970 1980 1990 2000 FIGURE 5-1 70 60 50 H 40 m m m 30 20 10 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 Year Average Day Demand, mgd Maximum Day Demand, mgd Available Production Capacity, mgd Notes 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 2005 6.85 13.16 13.8 Donner Lake Intake and Greenpoint Springs 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 P otable Water Demand vs. Existing Producti on Capacity, 1990-2025 30.0 25. 0 20. 0 ao E c 15. 0 co E a) 0 -- Historic Average Day Demand Future Averag e Day D emand Projection -- Historic Maximum Day D emand Future Maximum Day Production Projection Total Pr oduction Capacity Firm Production capacity 1990 1995 2000 2005 0. 0 Ye ar 2010 2015 2020 2025 Section 5 — Water Supply Sources Table 5-2. Groundwater Well Arsenic and Radon Levels Name Arsenic Level, ug/L Radon Level, pCi/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 Regulations Name Year 2004 Total Capacity, gpm Year 2004 Firm Capacity, gpm Year 2006 Total Capacity, gpm Year 2006 Firm Capacity, gpm 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 Oa 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 Year Maximum Day Demand, mgd Total Production Capacity, mgd Firm Production Capacity, mgd Notes 1990 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 2002 11.47 14.6 11.7 Includes DLWS and GWS Demands and 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 2005 13.16 13.8 10.4 Dormer Lake Intake and Greenpoint Springs removed from service. New 1,500 gpm Well Constructed 2006 13.71 15.4 12.5 (Featherstone Site). Northside Well capacity reduced to 500 gpm 2007 14.26 17.6 14.7 New 1,500 gpm Well Constructed (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 2026 24.67 28.4 25.5 Buildout 25.46 28.4 25.5 Page 5-11 Figure 5-3 . Pr ojected Potable Water Demand vs . Prop osed Production Capacity, 1990-2025 30. 0 25. 0 20.0 TS cn E 15. 0 ea E C 10. 0 5. 0 0. 0 1990 --�— Historic Av erage Day Demand Future Average Day Demand Projection t Historic Maximum Day Demand Future Maximum Day Production Projection Total Production Capacity Firm Production Capacity 1995 2000 2005 2010 Year 2015 2020 2025 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 PROSSER ANNEX16EL1. ,ALDER DRIVE TEST WELL PROSSFR HEIGHTS N4L PROSIER DAM ROAD TEST WELL RBRESONID TE/ST WELL I VILLAGE WELL FEATHERSTONE TEST WELL HMS TEST WELL WELL .-I RTIS VALLEY WELL NO 1 0RSC' RWErL WELL NO. 20 LEGEND • EXISTING NELL • FAVORABLE TEST WELL SHE (PROPERTY SECURED) • UNFAVORABLE TEST WELL SITE 4 TRUCKEE DONNER Public Utility District Figure 5-4 Location of Test Wells and Future Well Sites APPENDIX B August 2008 Land Use Analysis By Acumen Engineering ACUMEN ENGINEERING C O M P A N Y Mr. Michael Holley, General Manager Truckee Donner Public Utility District PO Box 309 Truckee, California 96160 Re: Water Supply Assessment, Truckee Railyard Master Plan Project Updated Land Use Analysis Dear Mr. Holley: August 27, 2008 On behalf of Truckee Development Associates, LLC, Acumen Engineering has prepared the enclosed Updated Land Use Analysis and Water Demand for Residential and Planned Unit Development Projects covering the period of August 2004, through May 31, 2008. The update was initiated as a result of a request by the Town of Truckee, to the Truckee Donner Public Utility District, for the preparation of a Water Supply Assessment (WSA) for the Truckee Railyard Master Plan Project. The WSA estimated the annual water demand for the Railyard Master Plan Project to be 406 acre-feet based on the Maximum Allowable Development (MAD) contained in the Truckee Railyard Master Plan dated November 2007. This amount exceeds the 152 acre-feet annual demand projected for the property in the TDPUD's 2004 Water Master Plan (WMP) and subsequent 2005 Urban Water Management Plan (UWMP). The purpose of the Land Use Analysis is two -fold: • provide updated demand data to the TDPUD with respect to those parcels that have received land use entitlements since the adoption of the WMP and UWMP and, • based on the updated demand of the entitled parcels, determine if sufficient water is available to meet the estimated annual demand of the Railyard Master Plan Project based on the MAD. Methodology The Water Master Plan and Urban Water Management Plan projected a District -wide annual water demand of 14,619 acre-feet at build -out based on the sum of existing and future demands. The future demand was determined by identifying all vacant parcels (363) within the District and calculating a maximum daily demand for each parcel based on the property's size, zoning and location. Since the Plans were prepared, a number of the then vacant parcels have been developed. Acumen Engineering and TDPUD staff met to identify the parcels to be reviewed as part of the update process; single-family lots that could be not be further subdivided and parcels zoned for commercial use only were not considered as the water demand for those specific land uses are not expected to vary significantly from the estimates in the Plans as compared to parcels with a potential for a large number of residences. Of the large Residential and Planned Development zoned parcels, Staff identified 80 for review and analysis as their respective land owners had contacted the TDPUD re: possible development. That list was provided to the Town's Planning Department to confirm the parcels that have received a land use entitlement since the adoption of the WMP and UWMP and determine the maximum permitted development allowed on the parcel/project; 39 parcels meeting the criteria were identified for further review. Finally, four parcels have been purchased, or ACUMEN C O M P A N otherwise permanently reserved, for open -space use and thus future water demand on the parcels is eliminated. Result The attached spreadsheet presents the results of the investigation. Each parcel has been identified by the Map Identification Number and original APN contained in the WMP and UWMP, the owner/project name and a comparison made of the average daily and yearly demands estimated by the plans vs. demands based on the permitted land uses. Water demand increased on six of the parcels and decreased on the remaining 33 with an overall net decrease of 558 acre-feet (1,859 -1,301) as compared to the analysis contained in the 2004 WMP. As mentioned, an analysis by the TDPUD staff estimates an annual demand of 406 acre-feet for the Truckee Railyard Master Plan Project as compared to the 152 acre-feet projected in the adopted Plans. The 254 acre-feet shortfall (406 — 152) is approximately 45% of the 558 acre-feet of water no longer required to meet the estimated demands of the 39 parcels that have been entitled and the four that are no longer developable since the original analysis was completed in 2004. Furthermore the Truckee Railyard Project can be fully served within the 14,619 acre-feet of confirmed water supply. I trust this letter and the enclosed spreadsheet provide the information requested by the TDPUD Board and Staff and the Board will consider the adoption of a Water Supply Assessment for the Truckee Railyard Master Plan Project for the entire projected water use of 406 acre-feet. Thank you and staff for your cooperation and assistance with this review and please do not hesitate to contact me if you have questions concerning this report. Sincere) Bill Quesnel PE Principal Engineer 1 Enclosure: Updated Land Use Analysis and Water Demand Acumen Engineering PO B ox 3497 Truckee, CA 96160 Updated Land Use Analysi s a nd Water Demand for Truckee Do nner Public Utility Distric Residential and Planned Unit De velopment Project! Peri od fr om August 2004 to June 1, 2008 Urba n Water Master Plan As Permitted Urban Water Maste r Plan APN Map (prior to ID # developme nt) Donn er Lake Planning Area Owner/Descnpbon All owable Allowable Daily Dw elli ng Dw elli ng Yearly Average Day Yearly Daily Demand Area Units per Units for Av erage Day Demand Ma x Permitted Demand Demand Co unty Zoning Land Use D emand Unit Acr es acre parcel(s) Demand gall ons ac -ft Units f or Proj ect gallons ac -ft 9,11 17-080-07,-26 Robert Rittenhouse et al. Nevada RES-1 Residential 505 gaUDU 17 .83 1 17 8,585 9.6 19 9,595 10.7 12 17-150-05 Freeds Excavating Inc Nevada RES-1 Residential 505 gaUDU 4.00 1 4 2,020 2.3 4 2,020 2 .3 17 17-150-35 Enc Perlman Nevad a RES-1 Resid ential 505 g al/DU 7 .00 1 7 3,535 4.0 4 2,020 2 .3 34 18-180-09 The Cabins Nevad a RES-2 Residential 505 gal/DU 4 .98 2 9 4,545 5 .1 7 3 535 4.0 Plan ning Ar ea Subt otal 19,656 20.9 17,170 19 .2 Down to wn Planning Ana 19 19-420-34 Stone Ridge Nevada DSA-ORH Residential 505 gal/DU 9.35 24 224 113,120 126.7 73 36,865 41 .3 38 19-450-20 Benjamin & Claire Winter Nevada RES-2 Residential 505 gal/DU 4.00 2 8 4,040 4.5 1 505 0 .6 45 19-470-29 Greens at Pondero sa Nevada COM Commercial 1500 gal/acr e 3.18 0 0 4,770 5 .3 , 19 SFR 9,595 10.7 Gateway Planning A rea 4 18-010-43 Donner Crest Nevada RES-0.5 Residential - SF 505 gal/DU 32.36 0.5 16 8,080 9 .1 82 41,410 46 .4 10 18-570-49 Dennis Chez Nevada RES-0 5 Residential - SF 505 gal/DU 59.43 0.5 29 14,645 16 .4 6 3,030 3.4 Planning Ar ea Sub -t otal 121,930 136 .6 46,966 62.6 Gln shire Pla nning Area 3 49-010-65 Hartsock Subdivision Ne vada RES-2 Residential 547 gaUDU 19 .50 2 39 4 49-010-72 Elkhom Ridge Subdivisio n Nevada RES-1 Residential 547 gal/DU 39 .84 1 39 5 49-010-75 Cambridge Estates Phase IV Nevada RES-2 Residential 547 gaUDU 27 .55 1 25 6 49-040-20 Waddle Ranc h Nevada PD Planned 96.96 Develo pment 7 49-040-21 Waddle Ranch Nevada PD Planned 71.28 Deve lopmen t 13 49-290.06 William & Jan e Adams Nevada RES-2 Residential 547 gaUDU 4.88 2 9 14 49-290-07 Gary & Mary Markwardt Nevada RES-2 Residential 547 gal/DU 4.88 2 9 16 110-010-27 Waddle Ranch Placer PD Planned Development 8.20 Plannin g Area Subtotal Planning Area Sub -total 22,725 26 .6 44,440 49 .8 21,333 23.9 5 2,735 3.1 21,333 23 .9 66 36,102 40.4 13,675 15.3 25 13,675 15.3 53,166 59 .6 Co ns er vation 0 0.0 Easement 39,085 43 .8 Conservation 0 0.0 Easement 4,923 5.5 2 1,094 1.2 4,923 5.5 2 1,094 1 .2 4,496 5 .0 Conservation 0 0 .0 Easement 162,934 182.6 54,700 61 .3 Page 1 of 3 8/27/2008 Acumen Engineering PO Box 3497 Truckee, CA 96160 Updated Land Use Analysis and Water Demand for Truckee D onner Public Utility Distric Residential and Planned Unit Devel opment Pr oject: Period from August 2004 to June 1, 2008 Urban W ater Master Pla n As Permitted Urban Water Allowable Allow able Master Plan APN Daily Dwelling Dwelling Yearly Av erag e Day Yearly Map (prior to Daily Demand Ar ea Units per Units for Average Day Demand Max Permitted D em and Demand ID 8 development) Owner/Description County Zoning Land Use Demand Unit A cres acre parcel(s) Demand gall ons ac -ft Units for Project gallons ac -ft Northeast Pla nnin g Area 16 19-370-17 G rays Crossing Nevada PC -2 Pl ann ed 94.55 0 113,008 126 .6 0.0 Development 17 19-370-18 Grays Crossing Ne vad a PC -2 Planned 91.50 0 109,363 122 .5 0 .0 Development 18 19-370-19 Grays Crossing Nevada PC -2 Planned 54 .87 0 65,582 73.5 0 .0 Development 19 19-370-20 Grays Crossing Nevada PC -2 Planned 56 .08 0 67,028 75.1 0 .0 Development 20 19-370-21 Grays Crossing Nevada PC -2 Planned 45.15 0 53,964 60.5 0.0 Development 21 19-370-22 Grays Crossing Nev ada PC -2 Planned 54 .73 0 65,414 73.3 0 .0 D evelopment 22 19-370-23 Grays Cro ssing Nevada PC -2 Pl anned 45.42 0 54,287 60.8 0.0 Development 23 19-370-24 G rays Cro ssing Nevada PC -2 Planned 50.24 0 60,048 67.3 0.0 Development 24 19-370-25 Grays Crossing Nevada PC -2 Plan ned 46 .75 0 55,876 62.6 Developme nt 0.0 25 19-370-26 Grays Cro ssing Ne vada PC -2 Plan ned 51.01 0 60,968 68.3 0.0 Development 41 19-410-09 Frischman Hollow Neva da PC -2 Planned 24 .72 0 29,546 33 .1 Development 0 .0 43 19-410-19 Grays Crossing Nevada PC -2 Planned 47 .04 0 56,223 63.0 Development0.0 44 19-410-21 G rays Crossing Nevada PC -2 Planned 22 .63 0 27,048 30 .3 0 .0 Dev elopme nt 45 19-410-22 Grays Crossing Nevada PC -2 Planne d 14.16 16,924 19 .0 0 .0 Development 46 19-410-24 Gra ys Crossing Nevada PC -2 Planned 44 .11 0 52,721 59 .1 Development 0 .0 Summary of Grays Crossin g Assumptions 500 afr, 100 affordable re sidential, 50 ac comml at 1500 gpd/ac, golf 360k gpd, r esort 150k gad 888,000 994.8 Se e Detail Below 821,630 920.4 42 19-410-10 Spring Creek westP 9 Nev ada RH Residential 505 gaUDU 10.81 130 65,650 73.5 66 33,330 37.3 66 48-220-13 The Bluffs Nevada RES-0.5 Re sidential 505 gal/DU 71.82 143 72,215 80 .9 31 15,655 17.5 96 49-250-01 Dan & Cecilia Cheyne y Nevada OSR Residential 505 ga l/DU 39.00 1 505 0.6 3 1,515 1.7 So uthsids Plann ing Are a 11 19-450-44 Timbers Ne vada RH Residential 505 gal/DU 3.95 12 47 23,735 26.6 34 17,170 19.2 12 19-450-61 Winter Creek Nevada RH Residential 505 gal/DU 45.18 10 451 227,755 255 .1 146 73,730 82.6 15 19-540-01 Tahoe Moun ta in Meado ws LLC Nevada RH Residential 505 gal/DU 1. 62 12 19 9,595 10.7 16 8,080 9.1 20 19-620-15 Pinyon Creek Ne va da RH Residential 505 gal/DU 8. 53 6 51 25,755 28.9 40 20,200 22.6 Planning Area S ub -total 1,026,370 1,149.8 872,130 977.0 Plann ing Are a Subtota l 286,840 321.3 119,180 133.6 Page 2 of 3 8/27/2008 Acumen Engineering PO Box 3497 Truckee, CA 96160 Updated Land Use Analysis a nd Water Demand for Truckee Donner Public Utility Distric Residential and Planned Unit D evelopment Pr oject: Peri od from August 2004 to June 1, 2008 Urban Water Master Plan APN Map (pnor to ID # development) Tahoe Do nner Planning Area 2 45-190-16 35 46-230-03 68 17-020-25 Owner/De scnption Paul Klein Creeksde Estates Truckee Donner Land Trust County Zoning Nevada N evada Nevad a Grays Cro ssing As -Permitted Dev elopment Detail Permitted Use Estimated Wate r Demand COM RM-15 PD Demand Daily Annual A -F Single Family Residential Multi -Family Residential Live/Work Residential Office /Retail Hotel Room Hotel Co nference Center C ommunity Ce nter MiniMart an d Se rvice Station Church Site Golf Course 497 6 505 gal/day 207 6 455 gat/day 21 © 400 galday 38,900 sf © 0.4 galsf/day 300 rooms 6 234 gaUrm/da y 5,000 sf ® 2 gal/sf/day 9,000 sf © 0.4 ga l/sf/day 1,800 sf 4 gallsf 1 acre et 1500 galladday 360,000 gaUday 250,985 281 94,185 106 8,400 9 15,560 17 70,200 79 10,000 11 3,600 4 7,200 8 1,500 2 360,000 403 821,630 920 Daily Daily D ema nd Area Land Use Dem and Unit Acres Commercial 1500 0.55 Residential 505 gaUDU 4.25 Planned Development Allowable Dwelling Units per acre 505 gal/DU 280 .88 NA Urba n Water Ma st er Plan Allowabl e Dwelli ng Yearly Units for Aver age D ay Demand parcel(s) Demand gall ons ac -ft 44 18 Planning Ar ea Subt otal 825 0.6 22,220 15.4 9,090 6.3 32,135 22 .3 As Permitted Average Day Yearly Max Permitted Demand Demand Units for Project gall ons ac -ft 4 10 Conserv ation Easement 2,020 5,050 0 2.3 5.7 0.0 7,070 7.9 District T otal 1,671,619 1,859 1,161,655 1,301 Page 3 of 3 8/27/2008