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HomeMy WebLinkAbout08/16/2011, C 3 - 2011 WATER RESOURCES STATUS REPORT council Mwig D� j acEnba Report CITY OF SAN LUIS OBIS PO FROMc Carrie Mattingly, Utilities Director Prepared By: Gary W. Henderson,Water Division Manager SUBJECT: 2011 WATER RESOURCES STATUS REPORT RECOMMENDATION Receive and file the City of San Luis Obispo's 2011 Water Resources Status Report. DISCUSSION Annual reports relative to the City's water resources have been provided to the City Council since 1985. The 2011 Water Resources Status Report (WRSR) provides an overview of the City's existing water resources and serves as an update on water supply projects being implemented to meet the community's future needs. The attached report discusses four major topics: I. Existing Water Supply Status U. Multi-Source Water Supply III. Water Demand Management IV. Projected Water Supply Situation 2011 Water Resources Status Report Summary This past year's (July 1, 2010 to June 30, 2011)rainfall amounts were significantly above normal at the City's two water supply reservoirs. With the abundant rainfall this past year, the.City's water resources are in very good shape. Assuming an extended drought, period water supplies are still projected to last at least to 2022. The City is continuing to expand the use of recycled water and implement its ongoing water conservation program. In addition, the Nacimiento Pipeline Project was completed this past year and water deliveries to the City's water treatment plant began on January 5, 2011. While the current water supply situation is favorable, the City needs to continue its water conservation efforts to comply with State regulations and ensure long-term efficient use of its water resources. The 2011 WRSR provides a synopsis of the City's water supply status and its ongoing water conservation program efforts. Existing Water Supply Status The City's two water supply reservoirs (Salinas and Whale Rock) were at 99.3 percent and 80.9 percent of total storage capacity respectively as of June 30, 2011. The City's total water use for 2010 was 5,489 acre feet (af) compared to 6,134 of in 2009. The City's per capita water use was considerably lower in 2010 as compared to the previous year. The per capita use rate is not the CM Council Agenda Report—2011 Water Resources Status Report Page 2 amount that the average person uses but takes into account all water uses including residential, . commercial, industrial, landscape, etc. In 2010 the water use rate was 109 gallons per capita per day (gpcd), a decrease from 2009 use rate of 122 gpcd. There are likely a number of factors that led to this past year's drop in water use including significant rainfall and recessionary impacts (vacancy rates, etc.). Multi-Source Water Supply For over 20 years, one of the major goals of the City Council has been the pursuit of additional long-term water supplies to meet the current and future water demands of the community. With the recycled water program, ongoing water conservation efforts, and the Nacimiento Pipeline Project the City has attained this goal. This has been a significant accomplishment and will ensure reliable water supplies for the community well into the future. The Nacimiento Pipeline Project construction was completed this past year and water deliveries to the City of San Luis Obispo began in January of 2011. The City has contractual rights for 3,380 acre feet per year from Nacimiento Reservoir. Additional user sites continue to be added to the City's recycled water system. During 2010, six new sites were connected to the City's recycled water distribution system. The use of the recycled water at all of these sites is for landscape irrigation. Based on the policies adopted in the. City's Water and Wastewater Management Element (WWME), Table 1 below shows the available water supplies to serve the community's water demands. Table 1: Water Resource Availability Water Resource _ . _ 2011 Annual Availabili Salinas &Whale Rock Reservoirs 6,940 AF Safe Annual Yield Nacimiento Reservoir 3,380 AF Contractual Limit Recycled Water 153 AF 2010 Annual Usage Siltation to 2060 (500 AF) WWME Policy A 4.2.2 TOTAL 91973 AF Water Supply Accounting and Demand The policies in the WWME establish that the City will account for water supplies necessary to meet three specific community needs: 1) primary water supply, 2) reliability reserve, and 3) secondary water supply which are discussed in more detail in the 2011 Water Resources Status Report (Attachment A) and shown in Table 2 below. Table 2: 2011 Water Supply Accounting. Total Primary Water Reliability Reserve SecondaEAF Supply Su 9,973AF 7,791 AF 1,237 AF 94 C3-2 Council Agenda Report—2011 Water Resources Status Report Page 3 Water Demand Management The City's water conservation program continues to implement the California Urban Water Conservation Council's Best Management Practices as defined in the Memorandum of Understanding Regarding Urban Water Conservation in California. The program provides technical assistance and other beneficial services to the community. With adequate water supplies to meet both the current and future water needs as envisioned in the City's General Plan, the water conservation program will continue to play an important role in the future as the City potentially faces new water supply challenges attributable to climate change and regulatory requirements related to statewide water use reduction goals. Projected Water Supply Situation The City utilizes a computer model to project how long the City's available water supplies will last based on a number of assumptions. The model uses historical drought weather patterns, projected water demands, and other factors to forecast the City's water supply position and to make certain water policy recommendations. Assuming ongoing drought conditions, the model predicts current water supplies will last into the year 2022. The additional water resources available from the Nacimiento Project, recycled water, and ongoing conservation programs extends the City's water supply at least five years beyond what would be estimated without these water resources. Summary For the past twenty years, the City of San Luis Obispo has been pursuing additional water resources to meet the City's current and future water demands. The City has been a leader in the implementation of water conservation strategies since the late 1980s and the community has embraced the importance of using its water resources wisely. With the City Council's support for the use of recycled water from the Water Reclamation Facility and this past year's completion of the Nacimiento Project, the City of San Luis Obispo is very well positioned to meet both current and future water needs within the community. The City Council has accomplished the "multi- source" water supply policy as identified in the Water and Wastewater Management Element of the General Plan and has also successfully established the "reliability reserve"which will serve the City well in the event of unforeseen changes relative to the City's water supplies. FISCAL IMPACT There is no fiscal impact associated with the recommended action. ATTACHMENT 2011 Water Resources Status Report C3-3 Attachment C.Ity of sanlUIS a : P• Water Resources Status Report 2011 " Prepared by: Gary Henderson, Water Division Manager Ron Munds, Utilities Conservation Manager Jennifer Meft, Utilities Project Manager Deparbnem M 9 y.0_ x n �t �3`i�^t�'�f}`••.;—;. f'•• A ri��k�t�c�'� L � �..�. S t"b'r' -! � ¢ ��� 5. � �.._.,.��?..dr' l_::].i I t�.j ,,..f t_�T` w.. azv".r'hYt� c t� ��e'.`•akr�.' V I� Attachment TABLE OF CONTENTS L EXISTING WATER SUPPLY STATUS...................................................................I CurrentStatus....»....................................................»........................»......».....»...............»...1 IL MULTI-SOURCE WATER SUPPLY.......................................:................................3 WaterResource Availability........»....»....»....».»..»»..»...........»............»...........»....»........3 Salinas &Whale Rock Reservoirs».................».... .....».».»........».»..».....»»..»..._»»»...3 NacimientoReservoir.................................................................».........................a......»....»..4 RecycledWater...........................:.................:.................:..........................»............................4 Groundwater.:................................... ..............W..w:..........w..........................:......................4 Water Supply Accounting and Demand...................:........:..:.....W.................... .................5 III. WATER DEMAND MANAGEMENT.....................................................................6 CustomerService/Technical Assistance.........................................................»..»..»...»....»..8 PublicInformation&Education...:......:..................:...............................................................9 IV. PROJECTED WATER SUPPLY SITUATION....................................................10 Reservoir Storage Curve».........»...»»..».».....»..»».»......:.....». ...»»».»......».».».....».».»..10 V. SUMMARY.................................................... .................................:.....................10 C3-5 Attachment City of San Luis Obispo 2011 Water Resources Status Report The 2011 Water Resources Status Report for the City of San Luis Obispo was prepared by the Utilities Department to provide the City Council and community members with an update on the status of existing water resources. It also serves as an update on water supply projects being implemented to meet the community's future needs. The report covers four main areas: I. Existing Water Supply Status II. Multi-Source Water Supply III. Water Demand Management IV. Projected Water Supply Situation The report evaluates the existing water supply situation for the City,identifies the amount of water currently available to serve new development, and discusses iissues relative to existing polices and water projects and programs being pursued. I. EXISTING WATER SUPPLY STATUS The City currently utilizes five sources of water.supply to meet the community's water demand: Salinas Reservoir (also referred to as Santa Margarita Lake), Whale Rock Reservoir, Nacimiento Reservoir, groundwater; and recycled water from the City's Water Reclamation Facility. The City's newest water supply from Nacimiento Reservoir began delivering water to the City's water treatment plant in January of 2011. Current Status Table 1• Area Rainfall For the 2010-11 Location 2010/11Average % of , rainfall year (October g Average 1 through September City of SLO—Reservoir#1 31.5" 22.4" 141% 30), rainfall for the Whale Rock Reservoir 29.71" 19.7" 150% City was significantly Salinas Reservoir 35.01" 21.4" 164% above normal as 1.Rainfall through June 30,2011 reflected in Table 1. As of June 30, 2011, Salinas and Whale Rock Reservoirs were at 97.9 percent and 81.0 percent of total capacity respectively. For the 2010 calendar year, the water demand for the City was provided from four sources as shown in Table 2. The total water demand (based on water production figures) for all City uses in 2010 was 5,489 acre feet which was approximately 10.5 percent lower than the total water use for 2009. C3-6 2011 Water Resources Status Report Attachment' Page 2 Table 2: Water Supply Sources (acre feet) Salinas Whale Rock Groundwater Recycled, Total El 2,426 of 2,757 of 153 of 153 of 5 The total amount of City water use shown in Table 2 does not include domestic water delivered to Cal Poly State University. This use is separately accounted for from the University's available water supply from Whale Rock Reservoir. As of June 30, 2011, the City's available water storage in Salinas Reservoir (above minimum pool, see definitions at end of report) was 21,334 acre feet. The City's share of the Whale Rock storage (above minimum pool) was 14,425 acre feet. The combined total water storage available to meet City water needs from these two sources was 35,760 acre feet. This equates to 83 percent of maximum available storage. Based on the available water storage in both reservoirs, estimated water from Nacimiento Reservoir, estimated groundwater production, estimated recycled water deliveries, and assuming the return of drought conditions as experienced during the late 1980s, the City has approximately eleven years of water supply. This estimate is based on data derived from the City's computerized reservoir storage model and is shown in Figure 5 (Figures are provided at the end of report). The model assumes additional conservation measures, consistent with the City's Water Shortage Contingency Plan, are implemented when supplies are estimated to last three years or less. The various stages of conservation are indicated in Figure 5 and are discussed in more detail in the City's Water Shortage Contingency Plan. The Water Shortage Contingency Plan is an appendix to the Urban Water Management Plan that was updated and adopted in June of 2011. Water Consumption The total City water use for 2010 was approximately 10.5 percent lower than the use for 2009. Table 3 shows the population estimates from 2001 through 2010 as well as the total City water use and corresponding per capita use rate. The past ten-year average per capita water use was 121.6 gallons per person per day (gpcd). Chart 1:Water Use by Category Based on the policies Landscape contained in the Water and Irrigation Single Wastewater Management Non- 10% Family Element of the General Plan, Residential Residential the City uses the ten-year 29% 41,0 average per capita water use GL�;D to project the required water Multi-family Residential needed to serve the build-out 20% population as identified in the Land Use Element of the General Plan. C3-7 2011 Water Resources Status Report `J Attachment Page 3 Chart 1 shows the water use between different customer classes for 2010 which is consistent with previous years. (landscape irrigation is only that water use specific to dedicated landscape meters). While the per capita water use increased following the end of the 1986-91 drought and the end of mandatory conservation measures in 1992, the use rate has somewhat stabilized as shown in Table 3. The 2010 per capita water use was approximately 109 gpcd, which was a significant decrease from the 2009 use of 122 gpcd.There are likely a number of factors that led to this past year's drop in water use including significant rainfall and recessionary impacts (vacancy rates, etc.). Table-3: Population Estimates, Water Use & Rainfall Year Population Total Water Use Per Capita Rainfall (acre feet) (gpcd) (inches) 2001 44;347 5,886 119 24.53 2002 44,482 6,032 121 15.94 2003 44,357 5,968 120 22.91 2004 1 44;298 6,239 126 16.08 2005 1 44,687 6,098 122 40.09 2006 44,559 5,999 120 30.35 2007 44,433 6,493 130 10.28 2008 44,579 6,359 127 19.92 2009 44,829 6,134 122 L772010 44,948 5,489 109 Ten-year per capita averse 121.6 1.Rainfall amounts for July through June from Cal Poly weather station 2.Rainfall amount from County rain gage at City's Reservoir#I II. MULTI-SOURCE WATER SUPPLY The City has adopted a multi-source water policy to provide increased reliability for meeting the community's water supply needs. With the addition of the Nacimiento Reservoir supply, the City now has five sources of water.and has accomplished the goal of diversifying its water supply portfolio to meet current and future community needs. The following sections provide an overview of each water source available to the City. Water Resource Availability Salinas & Whale Rock Reservoirs Salinas and Whale Rock Reservoirs have been the City's primary water supplies for over 50 years. The County of San Luis Obispo Flood Control and Water Conservation District provides the oversight, operations, and maintenance of the Salinas Dam and water delivery facilities for the benefit of the City. The City pays the County for the associated costs for these services. The City provides the oversight, operations, and maintenance of the Whale Rock Reservoir for the benefit of the Whale Rock Commission. The Whale C3-8 2011 Water Resources Status Report Attachment Page 4 Rock Commission is a joint powers agency made up of Cal Poly State University, California Men's Colony, and the City. The City draws water from these two reservoirs in a coordinated manner to maximize the long-term water supply available from these two sources. In addition, the City has adopted policies in the Water and Wastewater Management Element of the General Plan to account for reductions in storage capacity at each lake resulting from siltation. Nacimiento Reservoir The City has been involved in the Nacimiento Project planning efforts for over 15 years. Construction of the 45-mile pipeline and related facilities was completed in December 2010. Water deliveries to the City's water treatment plant began on January 5, 2011. The City has a contractual right to 3,380 acre feet per year_and will likely maximize the use of this water each year since the contractual amount of water. cannot be carried over ("banked") from year to year. Current use for this first year is estimated to be about 2,000 acre feet. Recycled Water Recycled water use for the 2010 year totaled just over 153 acre feet, up over ten percent from 138 acre feet in 2009. During 2010, six new sites (eight additional meters) were connected to the City's recycled water distribution system (Table 4 below). The use of the recycled water at all of these sites is for landscape irrigation. Table 4:New Sites using Recycled Water in 2010; Site Address AF Los Verdes Park I HOA(2 meters) Los Osos Valley Road at South Higuera 6.5 acre feet DeVaul Park 1593 Madonna Road 2.0 acre feet DeTolosa HOA(2 meters) 1501 and 1601 Madonna Road 3.7 acre feet Los Osos Valley Road median Madonna Road @ Los Osos Valley Road 0.5 acre feet Mission Community Bank 3380 Higuera S. 0.5 acre feet Meathead Movers&Storage 3600 Higuera S. 0.5 acre feet Total 13.7 acre feet Two new development sites, Prefumo Creek Commons and the Hampton Inn, are planned to receive recycled"water in 2011. These new recycled water use sites are estimated to use ten acre feet per year. Groundwater The City uses one domestic well to supplement its other water supply sources. In addition, there is a non-potable well at the City's Corporation Yard for use for construction activities. There are two wells at the City's Laguna Lake Golf Course that provide for a portion of the golf course irrigation needs. The additional irrigation demands at the golf course are met with recycled water. C3-9 2011 Water Resources Status Report Attachment Page 5 Based on the policies adopted in the City's Water and Wastewater Management Element of the General Plan, Table 5 below shows the available water supplies to serve the community's water demands. Table 5: Water Resource Availability - - - . . Water Resource 2010 Annual Availabili " - - - - - - Salinas_&Whale Rock Reservoirs_ 6,940 AF Safe Annual Yield Nacimiento Reservoir 3,380 AF Contractual Limit Recycled Water 153 AF 2010 Annual Usa e Siltation to 2060 (500 AF) WWME Policy A 4.2'.2 TOTAL 99973 AF . Water Supply Accountinx and Demand The policies .in the Water and Wastewater Management Element of the General Plan establish that the City will account for water supplies necessary to meet three specific community needs: 1) primary water supply, 2) reliability reserve, and 3) secondary water supply which are discussed in more detail below and shown in Table 6. Primary Water Supply The primary water supply is defined as the amount of water needed to serve the build-out population of the City as identified in the Land Use Element of the General Plan. The quantity of water needed for the primary water supply is calculated using the ten-year average of actual per capita water use, shown in Table 3, and the City's build-out population (57,200). Reliability Reserve The reliability reserve provides a buffer.for future unforeseen or unpredictable long-term impacts to the City's available water supply. The quantity of water for the reliability reserve is established using twenty percent of the ten-year average of actual per capita water use and the existing City population. The reliability reserve concept is included in the City's Charter (Section 909) which identifies that the water cannot be used to allow additional development. Secondary Water Supply The secondary water supply.is the amount of water remaining from the City's available water resources above those needed to meet the primary water supply and reliability reserve. The secondary supply is identified to meet peak water demand periods or short= term loss of City water supply sources. C3-10 O 2011 Water Resources Status Report Attachment Page 6 Table 6: 2011 Water Supply Accounting Total Primary Water Reliability Reserve _ y Secondary Water Supply l Supply 9,973 AF 7,791 AF 1,237 AF 945 AF JI III.WATER DEMAND MANAGEMENT The City's water conservation program is an integral part of its overall water management strategy. The program has assisted in adding reliability to the water supply system over the years. In the late 1980's, the City implemented effective water efficiency programs and policies that allowed continued growth and economic development within the community even during water-constrained periods. Even with a more diversified multi-source water supply portfolio in 2011, conservation will continue to play an important role in the future as the City potentially faces new water supply challenges attributable to climate change and regulatory requirements related to statewide water use reduction goals. Historically the City has utilized the California Urban Water Conservation Council's (CUWCC) Best Management Practices (BMPs) as defined in the Memorandum of Understanding Regarding Urban Water Conservation in California (MOU) as a guide for the City's water conservation program. The BMPs are programs and services that MOU signatories agree to implement over time. Based on the BMPs, the City's water conservation program in the past has been divided into three primary components: financial incentives, technical assistance, and public education. Because of the changing regulatory requirements and water supply availability, the following sections describe the shifting role of water conservation within the community and the evolution of the programs and services offered by the Utilities Department. Recent Water Use Efficiency Legislation There are two pieces of legislation that have been passed since 2007 that require water agencies to implement water conservation measures in order to be eligible for state grants, loans, or assistance. Eligibility for grants and loans apply to both water and wastewater projects that the City may undertake. The following is a summary of the legislation: AB 1420 Assembly Bill 1420 (Stats. 2007, ch. 628) amended the Urban Water Management .Planning Act, Water Code Section 10610 et seq., to require, effective January 1, 2009, that the terms of, and eligibility for, any water management grant or loan made to an urban water supplier and awarded or administered by the Department of Water Resources (DWR), State Water Resources Control Board, or California Bay-Delta Authority, be conditioned on the implementation of the water Demand Management Measures (DMMs) C341 2011 Water Resources Status Report Attachment Page 7 described in Water Code Section 10631(f). DWR was given discretionary authority to determine whether an urban water supplier is eligible for a grant or loan. SBx7-7 Senate Bill x7-7 was enacted in November 2009, requiring all water suppliers to increase water use efficiency. The legislation sets an overall goal of reducing per capita urban water use by 20 percent by December 31, 2020. The law directs incremental progress towards this goal by reducing per capita water use by at least ten percent by December 31, 2015. The law states: • Each urban retail water supplier shall develop water use targets and an interim water use target by July 1, 2011. • An urban retail water supplier shall include in its water management plan, due July 2011, the baseline daily per capita water use, water use target, interim water use target, and compliance per capita water use. • Effective 2016, urban retail water suppliers who do not meet the water conservation requirements established by this bill are not eligible for state grants or loans. Table 7: 2015 and 2020 Targets_ . The City's 2010 Urban Water Management Plan Year Adjusted Per provides a complete discussion of the legislative Ca ita Target requirements. Table 7 summarizes the per capita 2015 120 gpcd targets the City must meet in order to be in compliance with the law.. 2020 117 gpcd Financial Incentives Summary Financial incentives have been an important tool for the water conservation program since 1990. For a number of years, toilet retrofitting was the focus of the incentive program with the toilet rebate program running from June 1990 through June 2007. The high efficiency washing machine rebate program was added to the financial incentive program in 2001 and is still in place today within minimum funding levels. New irrigation equipment incentive pilot programs were tested in the summer/fall of 2008 and were added to the incentive program in 2009. The following is a summary of the financial incentive programs. C3-12 2011 Water Resources Status Report Attachment Page 8 High Efficiency Washing Machine Replacements The high efficiency washing machine rebate program was implemented in 2001 and offers a $150 dollar rebate for qualifying machines. As indicated in Table 8, participation in the program has been up and down over the years. In Table 8: Washing Machine Rebates 2009 the program had a Year Rebate Savings in acre record high of 175 rebates. _ feet per year In 2010 rebate funds were 2001-2005 354 5.97 reduced by 50% thereby 2006 47 .78 limiting the number of 2007 76 1.2 participants in the program. 2008 147 2.26 It is estimated that about 2009 175 2.70 14.11 acre feet of water is saved annually by these 2010 76 1.2 water efficient machines To 799 14.11 with energy savings as a side - benefit. Irrigation Equipment Replacement Added to the financial incentive program in late 2008, the first irrigation efficiency rebates were issued in 2009. The focus of the program is on the replacement of old irrigation controllers in Table 9: 2010 Irrigation commercial landscapes. Prior to receiving the Equipment incentive, the irrigation system is required to be Description Number audited and repaired to bring it up to standards. Table 9 summarizes the participation in the program.. Irrigation 11 Controllers Customer Service/Technical Assistance. Residential and Commercial Assistance The City offers technical assistance to water customers via free indoor and outdoor water consultations or audits. The consultations can either Table 10- 2010 Water Audits be by phone or in person. In person consultations include indoor and outdoor leak detection services, Description Number irrigation system evaluation, landscape plant material information, and other information on how to use Excessive Irrigation 302 water efficiently. Toilet Leak 248 Irrigation Leak 173 The requests for consultations are typically received Service Line Leak 63 from people experiencing high water bills, residents C3-13 2011 Water Resources Status Report Attachment Page 9 participating in the low income assistance program, or customers requesting a utility bill adjustment through the Utility Billing Adjustment Committee. Water audits often reveal problems which are then corrected by the property owner resulting in lower water use and reduced water bills. The most common problems experienced by customers are summarized in Table 10. A total of 1,814 contacts were made, either by letter, telephone, or direct contact during 2010. Past practice included mailing letters to customers using more than 25 units of water per billing cycle in the summer and 20 units in the winter. In 2010, 1,475 letters were sent to customers with high water use. This program is being curtailed for fiscal year 2011-2012 due to adjusted priorities and workload measures in the Utilities Conservation section. Public Information & Education In an ongoing effort to educate the public,.the City provides informational brochures on a variety of water conservation, water quality, energy conservation, and recycling topics upon request. Additionally, a quarterly newsletter is produced which focuses on current information regarding water, wastewater, stormwater, and solid waste issues. The newsletter is mailed to approximately 21,000 households. Additional information has been distributed through paid media advertising, public service announcements, and participation at Farmer's Market, home shows, etc. In 1999, the Utilities Department implemented a water education program within San Luis Coastal Unified School District. The program targets third through fifth grade students and compliments the study of water within the School District's existing curriculum. Teachers have been enthusiastic about the program, particularly with the field trip to the Water Reclamation Facility. During the 2010-2011 school year, ten class presentations and eight field trips were given for schools within the City. The class presentations were 45 minutes and covered the subjects of the water cycle, treatment, use, conservation, and reclamation. The classroom presentation is a prerequisite for the field trip. A new water quality module focusing on storm water runoff and creek and ocean health has been developed. This will add another option for teachers to select when looking for water education activities. Eight water quality class presentations were given during this school year. Summary The City has implemented numerous programs over the years which have resulted in a dramatic decrease in per capita water use since the late 1980's. The water conservation program has provided many economic benefits to the community while adding reliability to the water supply. The program has also brought per capita water use to a level where it C3-14 2011 Water Resources Status Report O Attachment Page 10 will, be relatively straightforward for the community to be in compliance with the state's mandatory water reduction goals in the future. With adequate water supplies to meet both the current and future water needs as envisioned in the City's General Plan, the water conservation program will play a different but continuing role for the City in the future. IV.PROJECTED WATER SUPPLY SITUATION Reservoir Storage Curve The Reservoir Storage.Curve is integral to the City's annual water resource analysis. It is based on a computer model used to estimate the City's future reservoir storage in Salinas and Whale Rock Reservoirs, utilizing historical drought weather patterns, water use projections, reservoir data, and available water supplies from Nacimiento Reservoir, recycled water, and limited groundwater. The model is used to forecast the City's water supply position and to make certain water policy recommendations. Figure 5 shows the Reservoir Storage Curve. The model assumes implementation of Stage I conservation when supplies are projected to last only three years. Stages II and III conservation measures are implemented when water supplies are estimated to.last only two years and one year, respectively(as shown on Figure 5). The model was updated to reflect the City's current water storage and assumptions relative to water demands and drought conditions. The model predicts current water supplies will last into the year 2022(Figure 5). V. SUMMARY This past year's rainfall was significantly above normal for the area. The City's surface water supplies from Salinas and Whale Rock Reservoirs are in very good shape. Even with these available supplies, the community must continue to utilize water in an efficient manner. Water conservation will continue to be.an important element of the City's water resources planning in the future and the State's requirement for reducing urban water use. With the multi-source water policy, the completion of the Nacimiento Project this year, planned expansion of users for recycled water, strong water conservation programs, and other related policies which were adopted as part of the Water and Wastewater Management Element, the City has implemented a long-term strategy which will ensure a reliable supply of water to meet the current and future needs of the community. Attachments: 1. Definitions & Information 2. Figures 1-5 C3-15 ATTACHMENT_ Definitions & Information Safe Annual Yield: The maximum quantity of water which can be delivered from the water source each year during a critical dry period(i.e.historical drought period). Minimum Pool: Minimum amount of water in Whale Rock or Salinas Reservoirs below which water deliveries must be stopped. This amount is established at 2,000 acre feet which is left in the reservoirs to support aquatic habitat and other wildlife. Acre Foot: * I acre foot=325,851 gallons * Enough water to cover a football field with 1 foot of water * Enough water to serve approximately 3.5 average single family homes (in San Luis Obispo)per year Gallons per Capita per Day(gpcd): Calculation=Total Acre Feet x 325.851 City Population x 365 Present Water Demand(acre feet per year): Calculation= 145 gpcd x Current City Population x 365 325,851 Salinas Reservoir: Maximum Storage Capacity=23,842.9 acre feet Minimum Pool =storage amount when water extractions must cease=2,000 acre feet Surface Area=730 acres Drainage Area= 112 square miles;=71,700 acres Whale Rock Reservoir: Maximum Storage Capacity=40,662 acre feet Minimum Pool =storage amount when water extractions must cease=2,000 acre feet Surface Area.=594 acres Drainage Area=20.3 square miles= 13,000 acres C3-16 � J . m U) o N t0 O ``) � C � 3 0 c �}r��✓7Y 'fr�. ?�::-$'s;,.i�t v..:..'.�re>::.r_.::,3;..t:"3"x.i..'3.%4:�.n rv_:i"9 �y DOTS£ *11/01 01/60 �,'��•. i� w. v'�YiJ�rS1+..er L, 1Ay,.♦.:a.'.'�''^1 {it S:.A':M'�. �vt<.._'3+:v.. 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