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HomeMy WebLinkAboutItem #2 Water Wastewater Management Element Amendment2108 Meeting Date: April 11, Item Number: 2 PLANNING COMMISSION AGENDA REPORT SUBJECT: Amendment to the General Plan Water and Wastewater Management Element (GPA 1454-2018) and Proposed Negative Declaration of Environmental Effect (EID 1455-2018) PROJECT ADDRESS: Citywide BY: Jennifer Metz, Utilities Project Manager Phone Number: 805-781-7239 e-mail: jmetz@slocity.org FROM: Aaron Floyd, Deputy Director, Water Dave Hix, Deputy Director, Wastewater RECOMMENDATION: Adopt a resolution recommending the City Council adopt a Negative Declaration (EID 1455-2018) and approve an amendment to the City’s Water and Wastewater Management Element of the General Plan (GPA 1454-2018). DISCUSSION Background The City’s guiding policy document for water and wastewater planning is the General Plan, Water and Wastewater Management Element (WWME). The City originally adopted the WWME in 1987 to address water and wastewater services because of the vital role these resources play in the community and the far-reaching impacts of water-related policies on community growth and character. The WWME translates the General Plan’s Land Use Element capacity for development into potential demand for water supply and wastewater service. The proposed revisions to the WWME provides water supply information from the 2018 update to the City’s safe annual yield model. Updates are also provided for background information related to the Sustainable Groundwater Management Act, and the adoption of the Recycled Water Master Plan in 2017. Related to the provision of wastewater service, the amendment updates background information on flow monitoring, inflow and infiltration, the 2016 Wastewater Collection System Infrastructure Renewal Strategy, and Figure 3 which identifies existing capacity constrained areas in the City’s wastewater collection system. Recommended revisions to the WWME are provided in Attachment 1 in legislative draft format. Packet Pg 1 Update to Safe Annual Yield Model / Reduction in Safe Annual Yield The City uses a multi-source water supply to meet existing water demand and future demand envisioned under the City’s General Plan. These water supplies include water from Salinas, Whale Rock, and Nacimiento reservoirs, recycled water from the City’s Water Resource Recovery Facility, and groundwater. The City’s total water demand for the 2017 water year (October 1, 2016 through September 30, 2017) was 4,975 acre feet with 27 percent of that supply coming from Salinas and Whale Rock reservoirs. The City defines the terminology “safe annual yield” as the amount of water which can be reliably withdrawn annually from coordinated operation of Salinas and Whale Rock reservoirs. The City’s safe annual yield analysis is based on historical rainfall, evaporation, and stream flow data from 1943 through 2017 including drought periods in 1946-51, 1959- 61, 1976-77, and 1986-91. Key assumptions used in the model were that the "controlling drought period" was from 1986-1991. The 2018 update to the safe annual yield model, detailed in Attachment 4, added data from the most recent drought that ended in 2016 consistent with WWME programs. A 3.3.2 The City will update the safe annual yield computer model for Salinas and Whale Rock Reservoirs following severe drought periods to determine if any changes are necessary to the safe annual yield amount. A 3.3.3 The City will monitor ongoing research on the potential for long‐ term impacts associated with climate change to water supply resources. The 2018 update verified historical data, validated and documented calculations used in the model, and reviewed various climate change scenarios. For both Whale Rock and Salinas reservoirs, the analysis found the historical data included higher evaporation rates than data used in the existing model. The difference results in greater evaporation losses, approximately 30 percent higher than shown in the existing model. The update determined that the 2006-2016 drought period was more severe than the 1986-1991 drought used in the 2015 model. Therefore, the 2006-2016 drought period was used as the new controlling condition for the 2018 determination of the City’s safe annual yield. Nacimiento Reservoir 68% Whale Rock Reservoir 23% Recycled Water 5% Salinas Reservoir 4% 2017 Water Supply by Source October 1, 2016-September 30, 2017 Packet Pg 2 Existing and Updated Safe Annual Yield 2015 Model 2018 Model with Verified Historical Data (through 2006) 2018 Model with Verified Historical Data and Drought Period (2006-2016) Safe Annual Yield from Whale Rock and Salinas Reservoirs 6,940 6,590 4,910* NOTES: 1.All results are in acre feet per year and use data for the period of record through 2016. 2.Results are the combined City safe annual yield from Salinas and Whale Rock Reservoirs, based on a joint operating strategy. * Indicates staff recommendation. As part of the 2018 update to the safe annual yield model, three climate change scenarios were analyzed including climate scenarios by the U.S. Environmental Protection Agency, San Luis Obispo Council of Governments, and Nature Communications. Each climate projection was applied to the historical dataset for Whale Rock and Salinas reservoir’s inflow, precipitation, and evaporation. The City’s 2018 model was then used to calculate a revised safe annual yield assuming these conditions had prevailed during the historical period of record. The results of the modeling for the three scenarios are shown in Table 2. The SLOCOG scenario provides the greatest range from the City’s 2018 model with a safe annual yield of 850 acre feet lower than the staff recommendation to 160 acre feet higher than the staff recommendation. Safe Annual Yield Under Climate Change Scenarios Range under EPA Climate Change Scenarios Range under SLOCOG Climate Change Scenarios Nature Climate Change Scenario Safe Annual Yield from Whale Rock and Salinas Reservoirs 4,690 to 5,050 4,050 to 5,070 4,950 Scenario Compared to Staff Recommendation -220 to +140 -850 to +160 +40 NOTES: 1.All results are in acre feet per year and use data for the period of record through 2016. 2.Results are the combined City SAY from Salinas and Whale Rock Reservoirs, based on a joint operating strategy. It is impossible to know precisely how climate change will impact the precipitation and evaporation patterns on the Central Coast; however, the range of values provided by the models serve as an indication of potential future conditions. Based on the updated modeling and analysis of climate change scenarios, staff is recommending the safe annual yield from Salinas and Whale Rock reservoirs be reduced from 6,940 acre feet to 4,910 acre feet. Staff chose this figure as it was within the data range of two of the models and slightly more conservative than the third. The proposed amendment to the WWME updated water supply information reflects the reduction from the 2018 model. Packet Pg 3 The City declared Climate Action a top priority during its 2017-19 Financial Plan. Although it is not clear exactly how the City and its watersheds will be affected, climate change will impact future water supplies. To ensure water supply resiliency under worse- case scenarios, the City has developed a multi-source water supply, makes conservative water demand projections, and continues to pursue increased water use efficiency, increased water recycling, and groundwater recharge. Formula for Water Resiliency Table 3, City Water Resource Availability, reflects the staff recommendation for the reduction in safe annual yield from Whale Rock and Salinas reservoirs. With the reduction of 2,030 acre feet from safe annual yield identified in the update of the model in 2018, the additional 2,102 acre feet from the full allocation of Nacimiento Reservoir will be utilized to meet the City’s water demands over time, as buildout of the General Plan is realized, consistent with the City’s Water Supply Accounting & Demand Projection policies. City Water Resource Availability Water Resource 2018 Annual Availability Salinas and Whale Rock Reservoirs 4,910 AF Safe Annual Yield Nacimiento Reservoir 5,482 AF Contractual Limit Recycled Water 238 AF 2017 Annual Usage Siltation to 2060 (500 AF) Policy A 4.2.2 TOTAL 10,130 AF NOTE: The quantity of recycled water included as part of the City’s available water resources identified above, is the actual prior year’s recycled water usage (2017), per Policy A 7.2.2. Source: City of San Luis Obispo Utilities Department, 2018. Multi- Source Water Supply Conservative Water Demand Projections Water Use Efficiency Water Recycling Future Ground Water Recharge Water Resiliency Packet Pg 4 With the reduction in safe annual yield, the City continues to have an adequate water supply to meet the projected water demand of 57,200 residents. As shown in Table 4, future primary water supply demand is estimated to reach 7,496 acre feet per year (AFY) using a water demand rate of 117 gallons per person per day (gpcd). In addition to the City having adequate water supplies to meet primary water supply needs, the City has a reliability reserve that equals 20 percent of current water supply needs (1,225 AFY for 2017). Remaining water supplies, 1,409 AFY, make up the City’s secondary water supply. Other Proposed Updates Other modifications to the WWME are proposed to provide updated background information on: • Groundwater related to the Sustainable Groundwater Management Act, • Adoption of the Recycled Water Master Plan, • Flow monitoring, infrastructure renewal, and capacity constraints in the wastewater collection system, and • Wastewater flows to the City’s Water Resource Recovery Facility. Tribal Consultation On February 12, 2018, local Native American tribal groups that have a cultural and traditional affiliation with the City were formally noticed that an Initial Study of Environmental Review was being completed for the update to the City’s Water and Wastewater Management Element. On March 13, 2018, staff met with a representative of the Northern Chumash Tribal Council to discuss the proposed General Plan amendment. No concerns were identified. ENVIRONMENTAL REVIEW In compliance with the California Environmental Quality Act (CEQA), staff prepared an Initial Study, Negative Declaration (EID 1455-2018) to analyze the potential environmental impacts of the proposed amendment to the WWME. That analysis is provided here as Attachment 2. Staff is recommending that the Planning Commission adopt a resolution recommending the City Council adopt the Negative Declaration. Table 4: Water Supply Accounting Primary Water Supply = 117 gpcd x City Build-out Population = 117 gpcd x 57,200 x 365 day/year x Acre-Ft/325,851 gallons 7,496 Acre-Ft/year Reliability Reserve = 117 gpcd x City Population x 20% = 117 gpcd x 46,724 x 365 day/year x Acre-Ft/325,851 gallons x 20% 1,225 Acre-Ft/year Secondary Water Supply = Current Annual Availability – Primary Water Supply – Reliability Reserve = 10,130Acre-Ft/year – 7,496 Acre- Ft/year – 1,225 Acre-Ft/year 1,409 Acre-Ft/year NOTE: One acre foot of water is equal to 325,851 gallons of water. Packet Pg 5 ALTERNATIVES The Planning Commission could recommend City Council to utilize another climate change scenario to inform the reduction of safe annual yield. ATTACHMENTS 1. General Plan, Chapter 8, Water and Wastewater Management Element, in legislative draft format. 2. Initial Study, Negative Declaration (EID 1455-2018) 3. Resolution Recommending the City Council Adopt Amendments to the Water and Wastewater Management Element of the General Plan (GPA 1454-2018) 4. Technical Memorandum, Salinas and Whale Rock Reservoirs Safe Annual Yield, Water Systems Consulting, January 2018. Packet Pg 6     WATER AND WASTEWATER                                     Adopted: February 24, 1987 Last Revised: June 15, 2016  (Council Resolution No. 10725, 2016)  Draft, March 2018   Packet Pg 7 Chapter 8        Page 8‐2   Please see the next page. Packet Pg 8 Water and Wastewater Element        Page 8‐3   CHAPTER 8 WATER AND WASTEWATER TABLE OF CONTENTS     INTRODUCTION ........................................................................................................................................................... 8-5  A. WATER MANAGEMENT ...................................................................................................................................... 8-6  INTRODUCTION ................................................................................................................................................... 8-6  A 1.0 Background ............................................................................................................................................. 8-6  A 1.1 Purpose ................................................................................................................................................... 8-6  MULTI-SOURCE WATER SUPPLY ............................................................................................................................. 8-7  A 2.0 Background ............................................................................................................................................. 8-7  A 2.1 Goal ........................................................................................................................................................ 8-9  A 2.2 Policies .................................................................................................................................................. 8-10  A 2.3 Programs .............................................................................................................................................. 8-10  Water Resource Availability ..................................................................................................................................... 8-11  A 3.0 Background ........................................................................................................................................... 8-11  A 3.1 Goal ...................................................................................................................................................... 8-15  A 3.2 Policies .................................................................................................................................................. 8-15  A 3.3 Programs ....................................................................................................................................... 8-168-15  SILTATION .................................................................................................................................................................. 8-17  A 4.0 Background ........................................................................................................................................... 8-17  A 4.1 Goals ..................................................................................................................................................... 8-19  A 4.2 Policies .................................................................................................................................................. 8-19  A 4.3 Programs .............................................................................................................................................. 8-19  WATER SUPPLY ACCOUNTING AND DEMAND PROJECTION ............................................................................ 8-20  A 5.0 Background ........................................................................................................................................... 8-20  A 5.1 Goals ..................................................................................................................................................... 8-21  A 5.2 Policies .................................................................................................................................................. 8-21  A 5.3 Programs .............................................................................................................................................. 8-22  WATER CONSERVATION ......................................................................................................................................... 8-23  A 6.0 Background ........................................................................................................................................... 8-23  A 6.1 Goal ...................................................................................................................................................... 8-23  A 6.2 Policies .................................................................................................................................................. 8-24  A 6.3 Programs .............................................................................................................................................. 8-24  RECYCLED WATER ................................................................................................................................................... 8-25  A 7.0 Background ........................................................................................................................................... 8-25  A 7.1 Goals ..................................................................................................................................................... 8-27  A 7.2 Policies .................................................................................................................................................. 8-27  A 7.3 Programs .............................................................................................................................................. 8-27  B. WASTEWATER MANAGEMENT ....................................................................................................................... 8-28  INTRODUCTION ................................................................................................................................................. 8-28  B 1.0 Background ........................................................................................................................................... 8-28  B 1.1 Purpose ................................................................................................................................................. 8-28  WASTEWATER SERVICE .................................................................................................................................. 8-29  B 2.0 Background ........................................................................................................................................... 8-29  B 2.1 Goal ...................................................................................................................................................... 8-29  B 2.2 Policies .................................................................................................................................................. 8-29  B 2.3 Programs .............................................................................................................................................. 8-30  WASTEWATER TREATMENT ............................................................................................................................ 8-31  B 3.0 Background ........................................................................................................................................... 8-31  B 3.1 Goals ..................................................................................................................................................... 8-31  B 3.2 Policies .................................................................................................................................................. 8-31  B 3.3 Programs .............................................................................................................................................. 8-31  Packet Pg 9 Chapter 8        Page 8‐4   COLLECTION SYSTEM ...................................................................................................................................... 8-32  B 4.0 Background ........................................................................................................................................... 8-32  B 4.1 Goal ...................................................................................................................................................... 8-34  B 4.2 Policies .................................................................................................................................................. 8-34  B 4.3 Programs .............................................................................................................................................. 8-34  LIST OF FIGURES Figure 1 Multi Source Water Supply .................................................................................................................. 8-8 Figure 2 Recycled Water Water Reuse Master Plan Area and Distribution System ....................................... 8-26 Figure 3 Capacity Constrained Areas 8-30 Figure 34 Inflow and Infiltration Illustrated ......................................................................................................... 8-33 LIST OF TABLES Table 1. City Water Resource Availability ....................................................................................................... 8-11 Table 2. Annual Recycled Water Availability based on Influent Flow ............................................................. 8-15 Table 3. Whale Rock Reservoir Capacity Change .......................................................................................... 8-16 Table 4. Reservoir Storage Capacity ............................................................................................................... 8-17 Table 5. 2010 Water Supply Accounting ......................................................................................................... 8-21 Table 6. Highest Average Daily Flows to the Water Resource Recovery Reclamation Facility, ..................... 8-33 2006 to 20157 Packet Pg 10 Water and Wastewater Element        Page 8‐5   INTRODUCTION   The City's General Plan guides the use and protection of various resources to meet community purposes. It reflects  consensus and compromise among a wide diversity of citizens' preferences, within a framework set by State law. The  General Plan contains elements that address various topics.  The City decided to adopt an element addressing water resources and wastewater services because of the vital role of  these resources and the far‐reaching impacts of water policies on community growth and character. This element  translates the Land Use Element's capacity for development into potential demand for water supply and wastewater  services. This element outlines how the City plans to provide adequate water and wastewater services for its citizens,  consistent with the goals and policies of other General Plan elements.  Before adopting or revising any General Plan element, the Planning Commission and the City Council must hold public  hearings. The City publishes notices in the local newspaper and on the City’s website to let citizens know about the  hearings at least ten days before they are held. Also, the City prepares environmental documents to help citizens  understand the expected consequences of its planning policies before the hearings are held.  Anyone may suggest or apply for amendments to General Plan elements.   Packet Pg 11 Chapter 8        Page 8‐6   A. WATER MANAGEMENT   INTRODUCTION A 1.0 Background The original Water and Wastewater Management Element was adopted in 1987 around the time the City  experienced its most a severe drought period which lasted from 1986 to 1991. During this point in time  mandatory water use restrictions were instituted and restrictions on new development were imposed. Following  this period, the City pursued additional water supplies to meet the existing water needs of the community, as  well as to fulfill the goals of the General Plan. The policies in the Water Management section of the Element were  written in a manner to address the water scarcity issues the City was facing. With the addition of the Nacimiento  Water Project to the City’s water portfolio, the City has an adequate water supply to serve the community’s  existing and future water needs as defined by the General Plan. The 2010 revisions to the Water and Wastewater  Management Element reflected the change in the water supply situation.     The 2016 revisions to the Water and Wastewater Management Element are proposed to include a larger  contractual water supply from Nacimiento Reservoir, to update the daily per capita water use assumption used in  water supply accounting, and to reflect information from the Whale Rock Reservoir Bathymetric Survey and  Volumetric Study completed in 2013. updated the City’s water resource availability to include the full allocation of  the Nacimiento Reservoir increasing the City’s contractual supply from 3,380 acre feet to 5,482 acre feet  annually, updated the daily per capita water use assumption used in water supply accounting, and incorporated  information from the Whale Rock Reservoir Bathymetric Survey and Volumetric Study completed in 2013.    The 2018 revisions to the Water and Wastewater Management Element provide information from the 2018  update to the City’s safe annual yield model. The update verified historical data, validated and documented  calculations used in the model, incorporated data from the 2006‐2016 drought, and reviewed various climate  change scenarios. The updated data reduced the safe annual yield from Salinas and Whale Rock Reservoirs from  6,940 acre feet to 4,910 acre feet. Updates are also provided to background information related to the  Sustainable Groundwater Management Act and the adoption of the Recycled Water Master Plan in 2017.  A 1.1 Purpose The Water Management section of the Element includes goals, policies, and programs related to water supply,  demand, and other emerging issues.    Packet Pg 12 Water and Wastewater Element        Page 8‐7   MULTI-SOURCE WATER SUPPLY   A 2.0 Background The City is the sole water purveyor within the city limits. This allows the City to maintain uniformity of water  service and distribution standards, and to be consistent in developing and implementing water policy. As the sole  water purveyor, the City maintains control over water quality, distribution, and service to users of the system, as  well as ensuring consistency with the City's General Plan policies and goals.  The Water Element of the General Plan, first adopted in 1987, identified multiple water projects to meet  projected short and long‐term water demand. Having several sources of water avoids dependence on any one  source that may not be available during a drought or other water supply reduction or emergency. There is usually  greater reliability and flexibility if sources are of different types (such as surface water and groundwater) and if  the sources of one type are in different locations (such as reservoirs in different watersheds). In November of  1990, the Council affirmed the multi‐source concept.  Consistent with the multi‐source concept, the City obtains water from five sources: Salinas Reservoir (Santa  Margarita Lake), Whale Rock Reservoir, Nacimiento Reservoir, recycled water from the City’s Water Resource  Recovery Facility, and groundwater. See Figure 1.  Salinas Reservoir  The Salinas Dam was built in 1941 by the War Department to supply water to Camp San Luis Obispo and,  secondarily, to meet the water needs of the City of San Luis Obispo. The Salinas Reservoir (Santa Margarita Lake)  captures water from a 112‐square mile watershed and can store up to 23,843 acre‐feet. In 1947, the Salinas Dam  and delivery system was transferred from the regular Army to the U.S. Army Corps of Engineers. Since the late  40s or early 50s, the San Luis Obispo County Flood Control and Water Conservation District has operated this  water supply for the City under a lease from the U.S. Army Corps of Engineers. Water from the reservoir is  pumped through the Cuesta Tunnel (a one‐mile long tunnel through the mountains of the Cuesta Ridge) after  which it flows by gravity to the City’s Water Treatment Plant on Stenner Creek Road.  Whale Rock Reservoir  The Whale Rock Reservoir is a 40,662 acre‐foot reservoir created by the construction of an earthen dam on Old  Creek near the town of Cayucos. The dam was designed and constructed by the State Department of Water  Resources in 1961 to provide water to the City of San Luis Obispo, Cal Poly State University, and the California  Men’s Colony. The Whale Rock Dam captures water from a 20.3‐square mile watershed and water is delivered to  the three agencies through 17.6 miles of 30‐inch pipeline and two pumping stations. The City of San Luis Obispo  owns 55.05 percent of the water storage rights at the reservoir. The remaining water storage rights are divided  between the two State agencies with Cal Poly owning 33.71 percent and the California Men’s Colony owning  11.24 percent.  Nacimiento Reservoir  The Nacimiento Reservoir provides flood protection and is a source of supply for groundwater recharge for the  Salinas Valley. It is owned and operated by the Monterey County Water Resources Agency. Since 1959, the San  Luis Obispo County Flood Control and Water Conservation District has had an entitlement to 17,500 acre‐feet per  year (AFY) of water from the reservoir for use in San Luis Obispo County. Approximately 1,750 AFY have been  designated for uses around the lake, leaving 15,750 AFY for allocation to other areas within the County of San  Luis Obispo.  Packet Pg 13 Chapter 8        Page 8‐8   Figure 1 Multi Source Water Supply  Packet Pg 14 Water and Wastewater Element        Page 8‐9   The County completed began construction in 2007 on of a 45‐mile pipeline project to deliver water from the  Nacimiento Reservoir to five participating agencies and cities in 2010. The City has a contractual entitlement to  5,482 AFY of water from the project.  Recycled Water   Recycled water is highly treated wastewater approved for reuse by the California Department of Public Health for  a variety of applications, including landscape irrigation and construction dust control. Completed in 2006, the  Water Reuse Project created the first new source of water for the City since 1961 following construction of Whale  Rock Dam. The Project resulted in improvements at the City’s Water Resource Recovery Facility and an initial  eight miles of distribution pipeline. The City’s first delivery of recycled water took place in 2006. The City  estimates demand exists for approximately 1,000 acre feet of recycled water for landscape irrigation and other  approved uses. Additional information is provided on recycled water in subsections A 3.0, A 7.0, and B 3.0 of this  Element.  Groundwater  The groundwater basin beneath the City is relatively small and recharges very quickly following normal rainfall  periods. The groundwater basin also lowers relatively quickly during periods of below‐average rainfall. The City  envisions groundwater playing an important role in ensuring continued resiliency in its water supply portfolio.  The Sustainable Groundwater Management Act (SGMA) is a statewide law that empowers local agencies to adopt  groundwater management plans that relate to the needs and resources of their communities. In 2017, the City  became a Groundwater Sustainability Agency (GSA) over the area of the San Luis Obispo Valley Groundwater  Basin that lies beneath and within its jurisdictional boundaries. The San Luis Obispo Valley Groundwater Basin  “eligible entities” (City, County, Golden State Water Company, Edna Ranch Mutual Water Company‐East, Varian  Ranch Mutual Water Company, and Edna Valley Growers Mutual Water Company) are all working collaboratively  to comply with SGMA requirements for the entire groundwater basin. The GSA structure includes a Groundwater  Sustainability Commission which is an advisory body to the City Council and the Board of Supervisors. The  Commission consists of one member from the City Council, one County Supervisor and a representative of each  of the identified water companies. The City, County, and eligible entities are required by SGMA to work together  to create Groundwater Sustainability Plans by January 31, 2022.  Extensive use of groundwater sustained the City  through most of the drought of 1986‐1991. The City’s two largest producing wells were shut down in 1992 and  1993 when elevated nitrate levels were detected. The City stopped utilizing the Pacific Beach well in April 2015.  Due to new regulatory requirements, using the groundwater would require additional costly treatment before  the water could be used. Additionally, portions of the groundwater basin are contaminated with a chemical  solvent (tetrachloroethylene) which would require treatment facilities to remove. While the City does not  currently utilize potable water from wells, this remains a viable option for future use.     Private wells are in use in the City, such as the well operated by San Luis Coastal Unified School District at San Luis  Obispo High School. The City maintains a non‐potable well at the City’s Corporation Yard that is available for non‐ potable purposes by permit. The City’s Laguna Lake Golf Course also has two wells that meet a portion of the  irrigation demand for the course. The remainder of the irrigation demand for the golf course is met using recycled  water from the City’s Water Resource Recovery Facility.    A 2.1 Goal Ensure a long‐term, reliable water supply to meet both current and future water demand associated with  development envisioned by the General Plan.  Packet Pg 15 Chapter 8         Page 8‐10    A 2.2 Policies A 2.2.1  Multi‐Source Water Supply  The City shall utilize multiple water resources to meet its water supply needs.  A 2.2.2  Water Service within the City  A. The City will be the only purveyor of water within the City.  B. Appropriate use of privately‐owned wells is allowed on individual parcels. The use of the water from  a well shall only be utilized on the parcel on which it is situated.    A 2.3 Programs A 2.3.1 Work cooperatively on regional water issues and water resource planning (Water Resource Advisory  Committee, Whale Rock Commission, Groundwater Sustainability Commission, etc.).  A 2.3.2 Participate with the County of San Luis Obispo in the Integrated Regional Water Management Plan process.  A 2.3.3 Participate with other appropriate agencies in controlling invasive species which could impact the City’s  water supplies (i.e. quagga mussels).  A 2.3.4 Work with appropriate agencies to minimize water quality impacts from new development and other  activities in the watersheds of the City’s water supplies.  A 2.3.5 Continue to work with the County of San Luis Obispo on the operation and maintenance of Salinas Reservoir  and Nacimiento Water Project.  A 2.3.6 Complete sanitary surveys for the Salinas and Whale Rock Reservoirs every five years.  Packet Pg 16 Water and Wastewater Element         Page 8‐11   Water Resource Availability   A 3.0 Background As described in Section A 2.0, the City has five water resources to meet current and future City water demand:  Salinas Reservoir (Santa Margarita Lake), Whale Rock Reservoir, Nacimiento Reservoir, recycled water from the  City’s Water Resource Recovery Facility, and groundwater. In order to ensure water supply reliability, the City  must determine the amount of water available from these water resources on an annual basis. The method to  determine the available yield from each resource varies based on water right, contractual agreement, or the  amount of water actually supplied.  For Salinas and Whale Rock Reservoirs the term “safe annual yield” is used to define the annual amount of water  available from these two resources. The two reservoirs are operated in a coordinated manner to increase the  available water. In contrast, the “dependable yield” from Nacimiento Reservoir is the contractual amount of  water to which the City has rights. Since Nacimiento Reservoir is operated as a water supply project for Monterey  County, the concept of safe annual yield is not used for the City’s contractual water supply from this source. For  recycled water, the annual amount delivered is counted in the water availability calculation. Though groundwater  is part of the City’s water portfolio the City does not consider this supply in estimating available water resources  to meet community needs at this time.  Another issue the City must address is the potential impact of climate change on the City’s water resources.  Climate change could have a significant impact on future water availability in the form of droughts or increased  siltation in reservoirs as a result of wildland fires which could affect the safe annual yield of the City’s reservoirs.  As data becomes available and research on the topic continues, the City will monitor the make adjustments for  long‐term impacts to its water supply resources.  The following sections provide more detail about each water resource. Table 1 is a summary of the City’s  available water resources.    City Water Resource Availability  Water Resource 2018 Annual Availability  Salinas Reservoir (Santa Margarita Lake) and  Whale Rock Reservoir 6,940 AF 4,910 AF Safe Annual Yield  Nacimiento Reservoir 5,482 AF Contractual Limit  Recycled Water 187 238 AF 20157 Annual Usage  Siltation to 2060 (500 AF) Policy A 4.2.2      TOTAL 12,109 10,130 AF   Note: The quantity of recycled water included as part of the City’s available water resources identified above, is the actual prior year’s recycled  water usage (20157), per Policy A 7.2.2.  Source: City of San Luis Obispo Utilities Department, 20168.  Packet Pg 17 Chapter 8         Page 8‐12    Salinas and Whale Rock Reservoirs  For Salinas and Whale Rock Reservoirs the term “safe annual yield” is used to define the quantity of water which  can be withdrawn every year, under critical drought conditions. The safe annual yield available from Salinas and  Whale Rock Reservoirs is estimated by simulating the operation of these two water supply sources over a  historical period to determine the maximum level of demand that could be met during the most severe drought  for which records are available. The two reservoirs are operated in a coordinated manner to maximize the  available water from these sources. Salinas Reservoir fills and spills every two to three years due to its larger  drainage area and more favorable runoff characteristics, yet has higher evaporation rates. Whale Rock Reservoir  fills much less frequently. The combined yield from the two reservoirs can be maximized by utilizing water from  Salinas as the City’s primary source, and using Whale Rock as a backup source during periods when Salinas is  below minimum pool or unable to meet all of the demand. This approach increases the long‐term water supply  from these two sources.  Safe annual yield analyses of water supply sources are based on rainfall, evaporation, and stream flow  experienced during a historical period. The City’s safe annual yield analysis utilizes data from 1943 through 1991  including drought periods in 1946‐51, 1959‐61, 1976‐77, and 1986‐91.   In 1988, the City contracted with the engineering firm of Leedshill‐Herkenhoff, Inc., to prepare a detailed analysis  of the City's water supplies and create a computer model to determine safe annual yield, based on coordinated  operation of the two reservoirs. The report Coordinated Operations Study for Salinas and Whale Rock Reservoirs  was completed in 1989. Key assumptions used in the 1988 model were that the "controlling drought period" was  from 1946 to 1951 and that the City only used Whale Rock Reservoir when Salinas was below minimum pool or  could not meet the City’s monthly demand. The study also assumed a minimum pool at Salinas and Whale Rock  of 400 and 500 acre‐feet respectively. The minimum pool at each lake is the amount of water that must be left in  the lake for fishery and habitat resources. The current minimum pool established for each lake is 2,000 acre feet.  The study estimated the City’s total safe annual yield from the two reservoirs to be 9,080 acre‐feet per year. This  amount was never adopted by Council since the study period was only to 1988 and the City was then in a drought  period of unknown length.  In 1991, staff updated the computer model to examine the impact of the 1986‐1991 drought on safe annual yield  and revise the assumptions on the amount of water used from Whale Rock Reservoir each year to more  accurately reflect the way the City actually used that resource. The analysis determined that the 1986‐91 drought  was the critical drought of record for the two reservoirs. These revised assumptions resulted in a reduction in the  safe annual yield estimate.  The City maintains an Excel‐based model that estimates a safe annual yield based on historical climatic conditions  and reservoir operations. The model uses the historical record of inflow, evaporation, precipitation, and  downstream releases. To determine safe annual yield, the model then calculates the maximum amount that  could be withdrawn each year without drawing the reservoir below its minimum pool constraint.     Salinas Reservoir and Whale Rock Reservoir are located in different climate regions and have differing  characteristics. Whale Rock Reservoir has a larger storage volume than Salinas, but it has a smaller watershed to  provide natural recharge. Salinas Reservoir receives more runoff each year, but experiences higher temperatures  and higher evaporation rates, and spills more frequently than Whale Rock Reservoir. To maximize the available  supply from the two reservoirs, the City has operational strategies that recognize these differences. In general,  the strategies involve withdrawing water from Salinas Reservoir when it is available and using Whale Rock  Reservoir as‐needed to supplement the supply from Salinas.    The City’s safe annual yield model of the two reservoirs was first developed in 1988. At that time, the critical  drought period that controlled the safe annual yield was the 1946‐1951 drought. In 1991, the model was updated  to incorporate the hydrologic conditions experienced during the 1986‐1991 drought. That drought was the most  Packet Pg 18 Water and Wastewater Element         Page 8‐13   severe in the historical record to that point and became the new controlling condition for estimating safe annual  yield. The City estimated the combined SAY from the two reservoirs as 6,940 acre‐feet per year (AFY). This  estimate included the anticipated loss of storage volume due to siltation through the year 2010.     In 2017, the City contracted with Water Systems Consulting, Inc. (WSC) to update the safe annual yield model.  The update verified historical data, validated and documented calculations used in the model, incorporated data  from the 2006‐2016 drought, and reviewed various climate change scenarios. Based on the 2017 update, tThe  City’s safe annual yield, from the coordinated operation of Salinas and Whale Rock Reservoirs is 6,940 4,910 acre  feet. This includes reductions due to siltation at both reservoirs to the year 20102017. Future losses due to  siltation are addressed in Section 4.0 of this Element.  Packet Pg 19 Chapter 8         Page 8‐14    Nacimiento Reservoir  The “dependable yield” from Nacimiento Reservoir is the contractual amount of water that the City has rights to  from Nacimiento Reservoir. This amount is 5,482 acre‐feet per year. The San Luis Obispo County Flood Control  and Water Conservation District (County) has held an entitlement to 17,500 acre‐feet of water from Nacimiento  Lake since 1959. Since that time, a small portion has been dedicated for uses in the immediate areas around the  Lake. Several times in the past, the County has evaluated opportunities for utilizing water to meet identified  needs throughout the County. In the early 1990’s, the City was facing dire drought conditions and dwindling  water supplies and was considering building an emergency water supply project on its own to provide a new  water source. The City requested the County allocate 3,000 acre feet to the City on a permanent basis. While the  County denied this request, this triggered the initiation of investigations on a county‐wide basis for separate  contracts for use of the available water from Nacimiento Reservoir.  Engineering studies, environmental impact reports, dependable yield analyses, and preliminary design reports  were undertaken in an effort to meet the various water needs within the County. In 2004, the County requested  interested agencies to approve the contractual agreements for participation in the Nacimiento Project. The four  initial project participants included the cities of San Luis Obispo and Paso Robles, the Atascadero Mutual Water  Company, and the Templeton Community Services District. All of these agencies executed participation  agreements with San Luis Obispo County for entitlements of water which totaled 9,630 acre feet. Since 2004, the  County Service Area 10A, which serves the southern portion of Cayucos, has become a project participant (25  AFY). In addition, 1,750 acre‐feet was reserved for uses around the lake.  On June 29, 2004, the City Council authorized participation in the Nacimiento Water Project for the delivery of  3,380 acre‐feet of water. This amount is considered to be the City’s dependable yield from this water source and  will be utilized to meet existing and future water demands based on analyses prepared during the Nacimiento  Project planning process (“Nacimiento Reservoir Reliability as a Water Source for San Luis Obispo County”, Boyle  Engineering Corporation, October 2002).  In March 2016, the City Council approved the addition of 2,102 acre feet per year from Nacimiento Reservoir. At  that time, the City’s primary water supply and reliability reserve were fully satisfied by other existing water  supplies, so the additional 2,102 acre feet was included in to the City’s secondary water supply. Secondary water  supplies are used to meet short‐term losses to the City’s water supply due to events such as drought, pipeline  maintenance, and repair of infrastructure. With uncertainty of future climatic conditions, regulation and aging  infrastructure, the additional supply of Nacimiento water to the City’s portfolio reduces pressure on use of water  supplies in the Whale Rock and Salinas reservoirs. It would serve to extend these stored supplies during critical  water shortage periods. With the reduction of safe annual yield identified in the update of the model in 2018, the  additional 2,102 acre feet from the full allocation of Nacimiento Reservoir will be utilized to meet the City’s water  demands over time, as buildout of the General Plan is realized, consistent with the City’s Water Supply  Accounting & Demand Projection policies in Section A 5.2.    Recycled Water  With an average influent flow of just under 3.30 2.74 million gallons per day in 20152017, the City’s Water  Resource Recovery Facility produces over 3,000 acre‐feet of disinfected tertiary‐treated effluent per year. A  minimum of 1,807 acre‐feet is discharged to San Luis Obispo Creek annually to provide satisfactory habitat and  flow volume for fish species (steelhead trout) within the San Luis Obispo Creek environment. The balance makes  up the City’s available recycled water resource (See Table 2) which is available for approved uses including:   Landscape and golf course irrigation    Wetlands, wildlife habitat, stream augmentation   Groundwater recharge   Packet Pg 20 Water and Wastewater Element         Page 8‐15    Toilet flushing    Vehicle washing    Surface irrigation of orchards and vineyards    Landscape impoundments    Industrial cooling processes    Food crop irrigation   Annual Recycled Water Availability based on Influent Flow  Average Influent Flow to  WRRF WRF (MGD)  Treated  Effluent  Produced  (AFY)  Minimum  Average Daily  Creek Release  (MGD)1  Minimum  Annual Creek  Release (AFY)  Average Daily   Recycled Water  Availability (MGD)  Annual Recycled  Water  Availability  (AFY)  1  20157 Average  Flow 2.743.30 3,0663,696 1.6129  1,807 1.131.69 1,2591,889  Future Flow at  WRRF Design  Capacity   5.4  5,966  1.6129  1,807  3.79  4,159  NOTES:  1. 2015 2017 data was derived from WRRF average monthly influent data. Future annual recycled water volume is based on the design  capacity of the WRRF of 5.4 mgd in the design phase in 2018 2016.  Source: City of San Luis Obispo Utilities Department, 2016.    The design phase for the upgrade of the WRRF continues in 2018 is underway in 2016 to accommodate General  Plan buildout and maximize recycled water production. The upgrade will enable the City to consider potable  reuse in the future.      Additional background information on recycled water, as well as applicable goals, policies and programs, is  provided in subsection A 7.0 of the Water Section and subsection B 3.0 of the Wastewater Management Section.   A 3.1 Goal Manage the City’s water resources to meet the current and future water demand requirements associated with  development envisioned by the General Plan.  A 3.2 Policies A 3.2.1  Basis for Planning  The City will plan for future development through the Land Use Element taking into consideration available  water resources from the Salinas, Whale Rock, and Nacimiento Reservoirs and recycled water.  A 3.2.2  Coordinated Operation  The City will coordinate the operation of the Salinas, Whale Rock, and Nacimiento Reservoirs to maximize  available water resources.  A 3.2.3  Groundwater  The City will continue to use groundwater to enhance the resiliency of the City’s water supply portfolio. for  domestic purposes when available.  Packet Pg 21 Chapter 8         Page 8‐16    A 3.3 Programs A 3.3.1 An update on the water resource availability will be presented to the City Council as part of an annual Water  Resources Status Report.  A 3.3.2 The City will update the safe annual yield computer model for Salinas and Whale Rock Reservoirs following  severe drought periods to determine if any changes are necessary to the safe annual yield amount.  A 3.3.3 The City will monitor ongoing research on the potential for long‐term impacts associated with climate change  to water supply resources.       Packet Pg 22 Water and Wastewater Element         Page 8‐17   SILTATION   A 4.0 Background Siltation at reservoirs is a natural occurrence that can reduce the storage capacity over long periods. The  reduction of available storage reduces the safe annual yield of the reservoirs. Siltation at reservoirs varies  depending on factors such as rainfall intensity and watershed management practices. Numerous studies and  reports addressing siltation at Salinas Reservoir have been completed. The Whale Rock Reservoir Bathymetric  Survey and Volumetric Study was completed in May 2013.  During the drought period ending in 1991, water at Salinas Reservoir fell to record low levels. Recognizing the  unique opportunity presented by the low water level, the County of San Luis Obispo contracted with a local  engineering consultant to provide an aerial survey of the lake and prepare revised storage capacity information.  Early studies indicated average annual siltation rates from 23 acre‐feet per year to 34 acre‐feet per year. The  study done by the U.S. Geological Survey in 1975 estimated that the siltation rate was approximately 82 acre‐feet  per year. The 1990 analysis conducted by the County of San Luis Obispo indicates that the siltation rate is on the  order of 40 acre‐feet per year.  It should be noted that siltation impacts to the reservoirs are a long‐term impact to the resources and should be  considered in the City’s long range plans for adequate water resources. At an annual siltation rate of 40 AFY at  each reservoir, it would take approximately 530 years to fill up the Salinas Reservoir and 960 years to fill up  Whale Rock Reservoir. Siltation does not occur uniformly over time but the situation should continue to be  monitored into the future.   The purpose of the 2013 bathymetric survey and volumetric study at Whale Rock Reservoir was to determine the  level of siltation that has occurred in the reservoir since the dam’s completion in 1961. The study concluded that  sedimentation has reduced reservoir capacity by 4.2 percent in 52 years as shown in Table 3 and 4.     Whale Rock Reservoir Capacity Change    1961 Capacity:  40,662  Acre‐Ft @ Spillway ELV 216.0 NGVD29  2013 Capacity: 38,967  Acre‐Ft @ Spillway ELV 218.3 NAVD88  Capacity Loss due to  Siltation: 1,695 Acre‐Ft  Difference in Years: 52  Years  Siltation Rate: 32.6 Acre‐Ft/Year  Percentage Capacity Loss: 4.2%    Source: Whale Rock Reservoir Bathymetric Survey and Volumetric Study, 2013.    Packet Pg 23 Chapter 8         Page 8‐18    Reservoir Storage Capacity  Agency % Entitlement Original Storage Capacity (AF) Revised Storage Capacity (AF) Difference (AF) Revised Total Available Water * (AF) City of San Luis Obispo 55.05 22,384 21,451 933 20,350 Cal Poly 33.71 13,707 13,136 571 12,462 CMC 11.24 4,570 4,380 191 4,155 Total 100 % 40,662 AF 38,967 AF 1,695 AF 36,967 AF   Source: Whale Rock Reservoir Bathymetric Survey and Volumetric Study, 2013.  *Total Available Water is agency share of reservoir storage capacity minus agency proportional share of  minimum pool requirements.  The safe annual yield from the two reservoirs will be continually reduced as a result of siltation. The City’s  computer model is used to calculate the reduction in safe annual yield from Salinas and Whale Rock reservoirs to‐ date, which is reflected in the safe annual yield amount in Section A 3.0 which accounts for estimated siltation  losses to 20107.   Since the storage capacity for Salinas Reservoir was last estimated in 1990, the annual loss of 40 acre‐feet per  year can be applied from that date.   The estimated loss in storage capacity for Salinas Reservoir between 1990 and 2010 is 800 acre‐feet. The loss at  Whale Rock Reservoir between 1961 and 2013 was 1,695 acre‐feet. Based on these reduced storage capacities,  the computer model was used to estimate the safe annual yield from the combined operation of the two  reservoirs. With an estimated loss of 40 acre‐feet per year at each reservoir, the total safe annual yield from the  two reservoirs is estimated to be reduced by 10 acre‐feet per year.   Packet Pg 24 Water and Wastewater Element         Page 8‐19   A 4.1 Goals A 4.1.1 Accurately account for siltation in the Salinas and Whale Rock Reservoirs.  A 4.1.2 Recognize and account for future projected water losses due to siltation at Salinas and Whale Rock  Reservoirs.  A 4.2 Policies A 4.2.2  Accounting for Future Siltation  The City will account for estimated safe annual yield losses at Salinas and Whale Rock Reservoirs through  2060 by deducting 500 acre feet of available water supplies to account for these future losses. The siltation  rate will be updated as information becomes available from subsequent siltation analyses.  A 4.3 Programs A 4.3.1 Work cooperatively with other agencies and/or watershed management groups, including the County of San  Luis Obispo and Resource Conservation Districts, implementing best management practices (BMPs) to reduce  erosion and subsequent siltation consistent with other City watershed management goals and water quality  objectives included in the Conservation and Open Space Element.   A 4.3.2 Continue public education and outreach to property owners in the watersheds above the reservoirs to  encourage practices that reduce erosion and other practices that could impact siltation or water quality in  the reservoirs.  A 4.3.3 Consider periodic siltation studies at each reservoir to evaluate and document the impacts associated with  siltation.  A 4.3.4 An update on siltation at the City’s reservoirs will be provided to the City Council as part of the annual Water  Resources Status Report.  Packet Pg 25 Chapter 8         Page 8‐20    WATER SUPPLY ACCOUNTING AND DEMAND PROJECTION   A 5.0 Background The City is located in a Mediterranean climate that is prone to drought. As a result, the City has in the past  experienced serious water supply deficits. In 1991, during an extended drought, the community was within 18  months of running out of water in Salinas and Whale Rock Reservoirs. In fact, Salinas Reservoir was below  minimum pool and was not available to the City toward the end of this drought period. In 1996, citizens voted to  incorporate Section 909 into the City’s Charter identifying a water reliability reserve. In an effort to reduce the  impacts of drought on the community, the City Council has enacted numerous water policies to strengthen its  water resources portfolio. 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.  1. Primary water supply is the amount needed to meet the General Plan build‐out of the City. The quantity of  water needed for the City’s primary water supply needs is calculated using a ten‐year average of actual  per‐capita water use and the City’s build‐out population.  2. Reliability reserve provides a buffer for future unforeseen or unpredictable long‐term impacts to the City’s  available water resources such as loss of yield from an existing water supply source and impacts due to  climate change.  3. Secondary water supply is the amount needed to meet peak water demand periods or short‐term loss of  City water supply sources. The City’s secondary water supply is identified as any water supply resources  above those needed to meet the primary water supply and reliability reserve.  In order to support growth projections and other goals of the General Plan, the City must project how much  water will be needed to serve residents, businesses, and other users. This can be done by using different  methods, all of which involve assumptions about future usage rates and the numbers and types of users expected  in the future. There will always be some uncertainty in estimating development capacity (such as the number of  dwellings or residents) as well as the usage per customer type (such as acre‐feet per dwelling or per resident).  The estimating method must use reasonable assumptions, based on experience, to assure an adequate level of  water supply while not overstating demands.  To project the City’s primary water supply and reliability reserve into the future the City will use 117 gpcd which is  the maximum allowed per capita water use under Senate Bill X7‐7. This water use rate is used with the City’s  build‐out population and current population to project the primary water supply and reliability reserve. The City’s  remaining water resources make up secondary water supply.    Packet Pg 26 Water and Wastewater Element         Page 8‐21    Water Supply Accounting  Proposed Water Supply Accounting and Demand Projections    (City Buildout Population * 117 gpcd * 365  days) / 325,851 gallons =     Primary Water Supply    +    20% of Current City  Population * 117 gpcd * 365  days) / 325,851 gallons =     Reliability Reserve    +  All Remaining Supplies     Secondary Water Supply  = Annual  Availability  Notes:  1. The “Total” water supply is identified in Table 1. It includes safe annual yield from Salinas and Whale Rock Reservoirs, contractual limit from  Nacimiento Reservoir, annual recycled water usage for 20157, and deducts siltation losses at Salinas and Whale Rock Reservoirs to 2060.   2. Primary Water Supply is calculated using the City’s buildout population and the water use rate of 117 gallons per capita per day per policy A  5.2.2.  3. Reliability Reserve was calculated using the City’s population and 20 percent of the water use rate of 117 gallons per capita per day, per  policy A 5.2.3.  4. Secondary Water Supply includes the remaining water resources, identified in Table 1, per policy A 5.2.4.  Source: City of San Luis Obispo Utilities Department, 20168.    A 5.1 Goals A 5.1.1 Identify and meet the City’s multi‐ source water supply needs.  A 5.1.2 Accurately forecast future water demand for planning purposes.  A 5.2 Policies A 5.2.1  Water Use Rate  The City will utilize the per capita water use rate allowed by Senate Bill X7‐7 for projecting future potable  water demand established as 117 gallons per capita per day.   A 5.2.2  Primary Water Supply  The City shall establish the amount of water needed for General Plan build‐out using the water use rate  established in Policy A 5.2.1 multiplied by the projected General Plan build‐out population identified in the  Land Use Element.  A 5.2.3  Reliability Reserve  The City will establish a reliability reserve that is 20‐percent of the water use rate established in Policy A 5.2.1  multiplied by the current population. The water supply designated as the reliability reserve may not be used  to serve future development.  A 5.2.4  Secondary Water Supply  After accounting for primary water supply and a reliability reserve, any remaining water supplies shall be  utilized for meeting short‐term water supply shortages or peak water demands.  Packet Pg 27 Chapter 8         Page 8‐22    A 5.2.5  Paying for Water for New Development  New development shall pay its proportionate or “fair share” for water supplies, expanded treatment and  distribution system capacity and upgrades.  A 5.3 Programs A 5.3.1 An update on water supply accounting and demand projections will be presented to the City Council as part  of the annual Water Resources Status Report.  A 5.3.2 The City will conduct periodic updates to water development impact fees.  A 5.3.3 Prepare and update the Urban Water Management Plan every five years as required by the State.  A 5.3.4 Analyze and prepare water supply assessments for large new developments in accordance with State law.  A 5.3.5 Analyze the impacts of water efficiency programs and services to reduce overall water demand within the  City.  Packet Pg 28 Water and Wastewater Element         Page 8‐23   WATER CONSERVATION   A 6.0 Background Water conservation was first referenced as a part of the City's water management policy in 1973. In 1985, the  City adopted the Annual Water Operational Plan policy establishing water conservation as a means of extending  water supplies during projected water shortages. Since 1985, many technological and philosophical changes have  occurred which are proving water conservation to be both a short‐term corrective measure for immediate water  supply shortages and a long‐term solution to water supply reliability.  Because of the experience during the drought of 1986 to 1991, the City developed a Water Shortage Contingency  Plan (Plan) to deal with immediate, short‐term water shortages. The Plan is designed to require mandatory  actions when there is a projected five year supply of water remaining from available water resources. The Plan  uses water allocations based on customer classification as a means to decrease water use during critical water  shortages. For instance, residential customers are given a water allocation based on the average water use for  multi‐ or single‐family households having three occupants. If there are more residents, additional water may be  allocated with sufficient proof. Commercial customers are allocated water either by a reduction based on their  historical water use or by the average water use by business type. The Plan is also a required component of the  City’s Urban Water Management Plan which is updated every five years per State Water Code.  The Water Conservation Act of 2009, Senate Bill X7‐7 (SB X7‐7), was incorporated into the California Water Code  in 2009. The legislation directs urban water suppliers to adopt one of four methods to determine their urban  water use target. The method selected by the City corresponds to the Central Coast hydrologic region. The  Central Coast region’s 2020 target of 117 gallons per capita per day is the lowest in the state.   In terms of water supply reliability, the City was one of the original signatories to the Memorandum of  Understanding Regarding Urban Water Conservation (MOU) and has actively pursued the implementation of the  water efficiency best management practices (BMPs) prescribed in the MOU. The MOU was a negotiated  agreement between water purveyors statewide and environmental organizations on how best to utilize the  State’s water resources by incorporating conservation into their water management practices.  The BMPs have been developed over the years by water purveyors, environmental groups, and industry  stakeholders. They represent the best available water conservation practices based on research and experience  and include:   Water conservation pricing and rate structures   Technical assistance for water customers   Incentives for indoor and outdoor water saving technologies   Public information and outreach   Water audits  Additionally, the City has adopted the Ahwahnee Principles as part of the General Plan’s Conservation and Open  Space Element (COSE). The water conservation components of the principles align with both the indoor and  outdoor water conservation BMPs.  In the future, the The City will reevaluate and continues to update its water conservation efforts in response to  changing water demand, supplies, technology, and economic conditions.  A 6.1 Goal The efficient use of the City’s water resources to protect both short‐ and long‐term water supply reliability.  Packet Pg 29 Chapter 8         Page 8‐24    A 6.2 Policies A 6.2.1  Long‐term Water Efficiency  The City will implement water‐efficiency programs which are consistent with accepted best management  practices and comply with any State‐mandated water use reductions.  A 6.2.2  Short‐term Water Shortages  Mandatory water conservation measures as described in the City’s Water Shortage Contingency Plan may be  implemented when the City's water supplies are projected to last five years or less.  A 6.3 Programs A 6.3.1 Work cooperatively with other San Luis Obispo County water agencies to identify cooperative water  efficiency measures that can be implemented in each jurisdiction.  A 6.3.2 Participate in State and regional water conservation efforts and research and development opportunities.  A 6.3.3 Implement the Water Shortage Contingency Plan as required.       Packet Pg 30 Water and Wastewater Element         Page 8‐25   RECYCLED WATER   A 7.0 Background Water recycling was envisioned as part of the City’s overall water supply strategy since the 1980’s. In 1994, the  City completed a major capital improvement project at the Water Resource Recovery Facility that included  addition of tertiary treatment and other unit processes required to meet stringent effluent quality limits intended  to protect and enhance the receiving waters of San Luis Obispo Creek. While a municipal water reuse program  was envisioned at the time of this upgrade, the City did not receive regulatory approvals for diversion of treated  effluent for off‐site landscape irrigation and other approved uses until 2002.  The City’s 2004 Water Reuse Master Plan identifies the areas of the City to be served with recycled water (See  Figure 3, Water Reuse Master Plan Area and Distribution System), as well as potential customers and anticipated  future recycled water demand.   Recycled water deliveries began in October 2006. Additional sites continue to be connected to the recycled water  distribution system through retrofits of existing irrigation systems as well as the irrigation systems associated  with new development in the area. In the future, recycled water will be delivered to development in the Airport,  Margarita, and Orcutt specific plan areas and is being considered with development proposals for the Avila  Ranch, San Luis Ranch, and Madonna on LOVR specific plans. Recycled water will be used for the irrigation of  parks, streetscape, and median landscaping, common area (homeowners association) landscaping, and  landscaping in commercial centers, industrial areas, and business parks.  The City’s 2017 Recycled Water Master Plan identifies the areas of the City to be served with recycled water (See  Figure 2, Recycled Water Master Plan Area and Distribution System), as well as potential customers and  anticipated future recycled water demand.     Packet Pg 31 Chapter 8         Page 8‐26    Figure 2 Recycled Water Water Reuse Master Plan Area and Distribution System    Packet Pg 32 Water and Wastewater Element         Page 8‐27   A 7.1 Goals A 7.1.1 Maximize recycled water use for all approved purposes.  A 7.2 Policies A 7.2.1  Recycled Water Supply  The City will make available recycled water to substitute for existing potable water uses as allowed by law  and to supply new non‐potable uses.  A 7.2.2  Accounting for Recycled Water  The City will add total recycled water usage from the prior year to the City’s water resource availability on an  annual basis.  A 7.3 Programs A 7.3.1 Expand the recycled water distribution system to serve customers in the Recycled WaterWater Reuse Master  Plan area.  A 7.3.2 Review development proposals for projects within the Recycled WaterWater Reuse Master Plan area to  ensure recycled water is utilized for appropriate uses.  A 7.3.3 Annual recycled water usage will be presented to the City Council as part of the annual Water Resources  Status Report and will be added to the City’s water resource availability per policy A 3.2.1.   A 7.3.4 Consider the potential to deliver available recycled water supplies to customers outside the city limits,  including analysis of policy issues, technical concerns, and cost recovery, provided it is found to be consistent  with the General Plan.  A 7.3.5  Continue to explore potable reuse consistent with statewide regulations.  Packet Pg 33 Chapter 8         Page 8‐28    B. WASTEWATER MANAGEMENT   INTRODUCTION B 1.0 Background The Wastewater Management section was first incorporated into the Water and Wastewater Management  Element of the General Plan in 1987. The City owns and operates, under regulatory permits, a wastewater  collection system and a water resource recovery facility that produces recycled water. In order to adequately  maintain the systems, meet the needs of the community, and meet increasingly stringent regulations the City  implements infrastructure replacement and upgrade projects at the Water Resource Recovery Facility and  throughout the wastewater collection system. It also has a pretreatment program.  The 20168 revisions include updated data related to the City’s wastewater flows.     B 1.1 Purpose This section of the Water and Wastewater Management Element establishes goals, policies, and programs to  ensure provision of adequate sanitary sewer infrastructure and wastewater treatment capacity to accommodate  existing and future development in order to protect public health, human safety, and the environment.  Packet Pg 34 Water and Wastewater Element 92-8 egaP WASTEWATER SERVICE B 2.0 Background The City is the sole provider of wastewater service within the City. The service provides collection and treatment for residential, commercial, and industrial users on properties within the city limits. In 20180, the number of service connections is estimated to be 12,000 14,400. Through agreement, the City also provides service to the San Luis Obispo campus of California Polytechnic State University (Cal Poly) and the County of San Luis Obispo Airport. The collection system is primarily a gravity flow system. Where gravity flow is not feasible due to the topography, wastewater lift stations and pressurized force mains are used to move wastewater to the City’s Water Resource Recovery Facility on Prado Road. Sewer pipelines measure from six inches to 48 inches in diameter. The City completed a two-year Flow Monitoring and Inflow/Infiltration Study in 2012. Using data from this Study, pipeline condition data from its asset management database, and growth assumption from the General Plan’s Land Use (2014) and Housing (2015) elements, the City completed hydraulic modeling and its Wastewater Collection System Infrastructure Renewal Strategy in 2016. The Renewal Strategy identified a prioritized list of capital projects to address the City’s aging infrastructure. The Renewal Strategy also identified capacity constrained areas during wet weather events due to inflow and infiltration, shown in Figure 3. Inflow and infiltration is discussed further in section B.4.0. The Water Resource Recovery Facility is designed for an average dry-weather flow of 5.1 million gallons per day (mgd). Instantaneous peak flows exceeding 20 mgd are not uncommon during storm events due to infiltration and inflow into the wastewater collection system, discussed further in subsection B 4.0. As the City grows to its build-out population outlined in the Land Use Element, the average dry-weather flow of wastewater is expected to reach 5.4 mgd. In 20186, designmaster planning for the expansion of the Water Resource Recovery Facility to accommodate General Plan buildout is underway. When the WRRF is expanded in the future it will have a treatment capacity of 5.4 mgd. B 2.1 Goal Adequate wastewater collection and treatment service to meet the long-term needs of the City. B 2.2 Policies B 2.2.1 Service Outside the City Limits To receive City wastewater service, property must be annexed to the City. The City Council may authorize exceptions to this policy provid ed it is found to be consistent with the General Plan. B 2.2.2 Service Capacity The City's wastewater collection system and Water Resource Recovery Facility shall support population and related service demands consistent with the General Plan. B 2.2.3 Wastewater Service for New Development New development shall pay its proportionate or “fair share” of expanded treatment and collection system capacity and upgrades. New development will only be permitted if adequate capacity is available within the wastewater collection system and/or Water Resource Recovery Facility. B 2.2.4 City as Exclusive Provider The City will be the only provider of public wastewater treatment within the City (but on-site pretreatment of wastewater to meet City Standards may be required). Packet Pg 35 Chapter 8         Page 8‐30    Figure 3 Capacity Constrained Areas      B 2.3 Programs B 2.3.1 Expand capacity in the City’s collection system and Water Resource Recovery Facility in support of projected  wastewater flows.  B 2.3.2  Evaluate the potential for the wastewater flows of a proposed project to exceed the capacity of collection  and treatment systems.  B 2.3.3  The City will conduct periodic updates to its wastewater development impact fees.  Packet Pg 36 Water and Wastewater Element         Page 8‐31   WASTEWATER TREATMENT B 3.0 Background The Water Resource Recovery Facility processes wastewater in accordance with standards set by the State's  Regional Water Quality Control Board (RWQCB). The RWQCB issues a permit to the City under the National  Pollutant Discharge Elimination System (NPDES), setting standards for the discharge of treated wastewater. The  standards are to protect beneficial uses of the receiving water (San Luis Obispo Creek) including recreation,  agricultural supply, and fish and wildlife habitat.   The Water Resource Recovery Facility removes solids, reduces the amount of nutrients, and eliminates bacteria in  the treated wastewater which is then discharged into San Luis Obispo Creek. Solids are separated and treated, to  create biosolids. Biosolids are beneficially reused as compost, and/or soil amendment. As described in Section A  7.0, the Water Resource Recovery Facility has been producing tertiary treated recycled water for delivery to  water customers in the City since 2006.  The design phase for the upgrade of the Water Resource Recovery Facility is underway in 2016 with completion  of construction anticipated in 20202. The upgrade will enable the City to consider potable reuse, part of a One  Water concept, in the future.    B 3.1 Goals B 3.1.1 Wastewater treatment that meets or exceeds regulatory requirements and ensures the  protection of public  health and the environment.  B 3.1.2 Maximize recycled water production.  B 3.2 Policies B 3.2.1  Treating Wastewater  The City will treat all wastewater in compliance with approved discharge permits.  B 3.2.2  Recycled Water Production  The City will produce high‐quality, dependable recycled water, suitable for a wide range of uses.  B 3.2.3  Beneficial Use  The City will pursue treatment and disposal methods which provide for further beneficial use of wastewater  and biosolids.  B 3.3 Programs B 3.3.1 Prepare and implement Water Resource Recovery Facility master plan consistent with regulatory  requirements.  B 3.3.2 Work cooperatively on regional water quality issues.   Packet Pg 37 Chapter 8         Page 8‐32    COLLECTION SYSTEM B 4.0 Background The first sanitary sewers were built in San Luis Obispo in the late 1800s. Today portions of the collection system  are over 100 years old. It includes nine lift stations, approximately 135 miles of gravity sewer line and three miles  of force main. Approximately 2,900 manholes provide access to the collection system. The sewer lines are made  of a variety of materials, including terra cotta salt‐glazed pipe, vitrified clay pipe (VCP), polyvinyl chloride (PVC),  and asbestos concrete.  The City’s wastewater collection system requires maintenance to ensure uninterrupted flows and minimize  sanitary sewer overflows. Area and preventive maintenance programs are regularly evaluated to ensure their  effectiveness. The City also utilizes video inspection to prioritize problem areas for replacement, maintenance,  assess overall mainline conditions, conduct inflow and infiltration evaluations, and assess new construction.  The City issues discharge permits to and conducts inspections of facilities that have the potential to discharge  pollutants in concentrations that could pose a threat to worker safety, the wastewater collection system, and/or  the Water Resource Recovery Facility. Through its Pretreatment Program, the City also implements programs to  target constituents of special concern.  Like most cities in California, San Luis Obispo has separate sewer and storm drain systems. This means each  system of pipes in the ground is designed to accommodate either sewer or stormwater flows. One set of pipes  takes sanitary waste to the Water Resource Recovery Facility while a second set carries stormwater runoff from  street drains directly into bioswales, detention basins, or creeks.  The City’s wastewater collection system and the Water Resource Recovery Facility WRF have long experienced  problems associated with wet weather infiltration and inflow (I & I). Inflow is water that enters the collection  system at points of direct connection (non‐soil) such as around manhole covers or through illegal connection of  roof drains, downspouts, or landscape drains. Infiltration is water that flows through the ground into the  collection system usually through cracks in public sewer mains and/or private sewer laterals (See Figure 5). I & I  overloads the collection system during heavy rains and can result in sanitary sewer overflows. During periods of  significant rain events, the Water Resource Recovery Facility can become hydraulically overwhelmed (as  mentioned previously,  instantaneous peak flows exceeding 20 mgd are not uncommon during storm events)  increasing the chance of effluent violations and the release of partially treated wastewater to San Luis Obispo  Creek. Table 6 includes data on the highest average daily flows experienced at the Water Resource Recovery Facility during rain events over a nine‐year period.    Packet Pg 38 Water and Wastewater Element         Page 8‐33    Highest Average Daily Flows to the Water Resource Recovery Reclamation Facility, 2006 to 20157  Average Daily Flows 1 Year  19.75 mgd  2006 (April)  7.24 mgd  2007(December)  9.83 mgd  2008 (January)  11.67 mgd  2009 (October)  13.51 mgd 2010 (December) 13.23 mgd 2011 (March 7.10 mgd 2012 (January) 5.17 mgd 2013 (January) 5.12 mgd 2014 (March) 5.24 mgd 2015 (February) 5.63 mgd 2016 (March) 9.00 mgd 2017 (February) Note:   1. Instantaneous peak flows are higher.  2. August dry weather flow to the Water Resource Recovery Facility was 1.91 mgd in 2016 and 2.80 mgd in 2017. WRF from 2001 to 2009  ranged from 3.44 mgd to 4.23 mgd.  Source: City of San Luis Obispo Utilities Department, 20108.    Figure 34 Inflow and Infiltration Illustrated    Packet Pg 39 Chapter 8         Page 8‐34    B 4.1 Goal Collect and convey all wastewater under safe and sanitary conditions to the Water Resource Recovery Facility.  B 4.2 Policies B 4.2.1  Collection System Maintenance  The City will manage the collection system to ensure that the proper level of maintenance is provided and  that the flow in sanitary sewers does not exceed design capacity.  B 4.2.2  Infiltration and Inflow  The City will minimize stormwater and groundwater infiltration and inflow into the sewer system.  B 4.3 Programs B 4.3.1 Investigate and carry out cost‐effective methods for reducing infiltration and inflow into the wastewater  collection system.  B 4.3.2 Develop education and outreach materials to increase public awareness of problems associated with  excessive infiltration and inflow (I & I) into the wastewater collection system and the City’s efforts to reduce  I & I.  B 4.3.3 Support the retrofit of commercial and residential sewer laterals to reduce infiltration and inflow into the  wastewater collection system.  B 4.3.4 Update the Sewer System Management Plan to maintain its applicability.  B 4.3.5 Maintain, and revise as necessary, master plans for the extension of wastewater services to developing areas  of the City and to ensure orderly replacement of aged infrastructure.   B 4.3.6 Review development proposals to ensure new development does not adversely impact existing infrastructure  and that necessary infrastructure will be in place to support the development.  B 4.3.7 Provide a Pretreatment Program pursuant to the Clean Water Act to ensure that all discharge requirements  are met.    Packet Pg 40 INITIAL STUDY ENVIRONMENTAL CHECKLIST FORM For GPA 1454-2018 / EID 1455-2018 1. Project Title: 2018 Amendment to General Plan, Chapter 8, Water and Wastewater Management Element 2. Lead Agency Name and Address: City of San Luis Obispo Utilities Department 879 Morro Street San Luis Obispo, CA 93401 3. Contact Person and Phone Number: Jennifer Metz, (805) 781-7239 4. Project Location: Citywide, City of San Luis Obispo 5. Project Sponsor’s Name and Address: City of San Luis Obispo, Utilities Department 879 Morro Street San Luis Obispo, CA 93401 6. General Plan Designations: N/A 7. Zoning: N/A 8. Description of the Project: In 1987, the City adopted the General Plan Water and Wastewater Management Element (WWME) to address water resources and wastewater services because of the vital role of these resources and the far-reaching impacts of water policies on community growth and character. The City’s WWME translates the Land Use Element's capacity for development into potential demand for water supply and wastewater services. The WWME outlines how the City plans to provide adequate water and wastewater services for its citizens, consistent with the goals and policies of other General Plan elements. In 2014, the City updated the General Plan’s Land Use and Circulation Element which identified a potential Urban Reserve area population of 57,200. In 2017, the City’s total water use was 4,975 acre feet, or 95 gallons of water per capita per day (gpcd) for a population of 46,724. The project reviewed here is the 2018 amendment to the WWME (Exhibit 1). The amendments in the Water Management section are proposed to update water supply information following the update of the City’s safe annual yield model reducing safe annual yield from Whale Rock and Packet Pg 41 CITY OF SAN LUIS OBISPO INITIAL STUDY ENVIRONMENTAL CHECKLIST 2017 Salinas Reservoirs from 6,940 acre feet annually to 4,910 acre feet annually. Updates to the safe annual yield model are undertaken consistent with General Plan, Water and Wastewater Management Element, Program A 3.3.2. Incorporating the reduction in safe annual yield and recycled water use for 2017, the City’s total available water supply is 10,130 acre feet per year in 2018. Water Resource 2018 Annual Water Availability Salinas Reservoir (Santa Margarita Lake) and Whale Rock Reservoir 4,910 AF Safe Annual Yield Nacimiento Reservoir 5,482 AF Contractual Limit Recycled Water 238 AF 2017 Annual Usage Siltation to 2060 (500 AF) Policy A 4.2.2 TOTAL 10,130 AF Note: The quantity of recycled water included as part of the City’s available water resources identified above, is the actual prior year’s recycled water usage (2017), per Policy A 7.2.2. With the reduction in safe annual yield, the City continues to have an adequate water supply to meet projected water demand of 57,200 residents at 117 gpcd, a 20 percent reliability reserve, and over 1,000 acre feet as a secondary water supply. Updates in the Wastewater Management section of the WWME are proposed to update background information to reflect current conditions within the City’s wastewater collection system and Water Resource Recovery Facility. 9. Project Entitlements: General Plan Amendment 10. Surrounding Land Uses and Settings: N/A 11. Have California Native American tribes traditionally and culturally affiliated with the project area requested consultation pursuant to Public Resources Code Section 21080.3.1? If so, has consultation begun? Letters for a request for consultation were sent out February 12, 2018. 12. Other public agencies whose approval is required: None. Packet Pg 42 CITY OF SAN LUIS OBISPO INITIAL STUDY ENVIRONMENTAL CHECKLIST 2017 ENVIRONMENTAL FACTORS POTENTIALLY AFFECTED: The environmental factors checked below would be potentially affected by this project, involving at least one impact that is a “Potentially Significant Impact” as indicated by the checklist on the following pages. Aesthetics Greenhouse Gas Emissions Population / Housing Agriculture Resources Hazards & Hazardous Materials Public Services Air Quality Hydrology / Water Quality Recreation Biological Resources Land Use / Planning Transportation / Traffic Cultural Resources Mineral Resources Tribal Cultural Resources Geology / Soils Noise Utilities / Service Systems Mandatory Findings of Significance FISH AND WILDLIFE FEES X The Department of Fish and Wildlife has reviewed the CEQA document and written no effect determination request and has determined that the project will not have a potential effect on fish, wildlife, or habitat (see attached determination). The project has potential to impact fish and wildlife resources and shall be subject to the payment of Fish and Game fees pursuant to Section 711.4 of the California Fish and Game Code. This initial study has been circulated to the California Department of Fish and Wildlife for review and comment. STATE CLEARINGHOUSE This environmental document must be submitted to the State Clearinghouse for review by one or more State agencies (e.g. Cal Trans, California Department of Fish and Wildlife, Department of Housing and Community Development). The public review period shall not be less than 30 days (CEQA Guidelines 15073(a)). Packet Pg 43 Packet Pg 44 CITY OF SAN LUIS OBISPO INITIAL STUDY ENVIRONMENTAL CHECKLIST 2017 EVALUATION OF ENVIRONMENTAL IMPACTS: 1. A brief explanation is required for all answers except “No Impact” answers that are adequately supported by the information sources a lead agency cites in the parentheses following each question. A “No Impact” answer is adequately supported if the referenced information sources show that the impact simply does not apply to projects like the one involved (e.g. the project falls outside a fault rupture zone). A “No Impact” answer should be explained where it is based on project-specific factors as well as general standards (e.g. the project will not expose sensitive receptors to pollutants, based on a project-specific screening analysis). 2. All answers must take account of the whole action involved, including off-site as well as on-site, cumulative as well as project-level, indirect as well as direct, and construction as well as operational impacts. 3. Once the lead agency has determined that a particular physical impact may occur, then the checklist answers must indicate whether the impact is potentially significant, less than significant with mitigation, or less than significant. "Potentially Significant Impact' is appropriate if there is substantial evidence that an effect may be significant. If there are one or more "Potentially Significant Impact" entries when the determination is made, an EIR is required. 4. “Negative Declaration: Less Than Significant with Mitigation Incorporated” applies where the incorporation of mitigation measures has reduced an effect from "Potentially Significant Impact" to a "Less than Significant Impact." The lead agency must describe the mitigation measures, and briefly explain how they reduce the effect to a less than significant level (mitigation measures from Section 19, "Earlier Analysis," as described in (5) below, may be cross- referenced). 5. Earlier analysis may be used where, pursuant to the tiering, program EIR, or other CEQA process, an effect has been adequately analyzed in an earlier EIR or negative declaration (Section 15063 (c) (3) (D)). In this case, a brief discussion should identify the following: a) Earlier Analysis Used. Identify and state where they are available for review. b) Impacts Adequately Addressed. Identify which effects from the above checklist were within the scope of and adequately analyzed in an earlier document pursuant to applicable legal standards, and state whether such effects were addressed by mitigation measures based on the earlier analysis. c) Mitigation Measures. For effects that are “Less than Significant with Mitigation Measures Incorporated,” describe the mitigation measures which were incorporated or refined from the earlier document and the extent to which they addressed site-specific conditions for the project. 6. Lead agencies are encouraged to incorporate into the checklist references to information sources for potential impacts (e.g. general plans, zoning ordinances). Reference to a previously prepared or outside document should, where appropriate, include a reference to the page or pages where the statement is substantiated. 7. Supporting Information Sources: A source list should be attached, and other sources used or individuals contacted should be cited in the discussion. 8. The explanation of each issue should identify: a) the significance criteria or threshold, if any, used to evaluate each question; and b) the mitigation measure identified, if any, to reduce the impact to less than significance Packet Pg 45 Issues, Discussion and Supporting Information Sources GPA 1454-2018 / EID 1455-2018 (2018 Amendment to General Plan, Chapter 8, Water and Wastewater Management Element) Sources Potentially Significant Issues Potentially Significant Unless Mitigation Incorporated Less Than Significa nt Impact No Impact 1. AESTHETICS. Would the project: a) Have a substantial adverse effect on a scenic vista? X b) Substantially damage scenic resources, including, but not limited to, trees, rock outcroppings, open space, and historic buildings within a local or state scenic highway? X c) Substantially degrade the existing visual character or quality of the site and its surroundings? X d) Create a new source of substantial light or glare which would adversely affect day or nighttime views in the area? X Evaluation a) b) c) d) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. No specific site is under consideration. Conclusion: The project will have no impact to aesthetics. 2. AGRICULTURE RESOURCES. Would the project: a) Convert Prime Farmland, Unique Farmland, or Farmland of Statewide Importance (Farmland), as shown on the maps pursuant to the Farmland Mapping and Monitoring Program of the California Resources Agency, to non-agricultural use? X b) Conflict with existing zoning for agricultural use or a Williamson Act contract? X c) Involve other changes in the existing environment which, due to their location or nature, could result in conversion of Farmland to non-agricultural use? X Evaluation: a) b) c) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. No specific site is under consideration. Conclusion: The project will have no impact on agricultural resources. 3. AIR QUALITY. Where available, the significance criteria established by the applicable air quality management or air pollution control district may be relied upon to make the following determinations. Would the project: a) Conflict with or obstruct implementation of the applicable air quality plan? X b) Violate any air quality standard or contribute substantially to an existing or projected air quality violation? X c) Result in a cumulatively considerable net increase of any criteria pollutant for which the project region is non-attainment under an applicable federal or state ambient air quality standard (including releasing emissions which exceed quantitative thresholds for ozone precursors)? X d) Expose sensitive receptors to substantial pollutant concentrations? X e) Create objectionable odors affecting a substantial number of people? X Packet Pg 46 Issues, Discussion and Supporting Information Sources GPA 1454-2018 / EID 1455-2018 (2018 Amendment to General Plan, Chapter 8, Water and Wastewater Management Element) Sources Potentially Significant Issues Potentially Significant Unless Mitigation Incorporated Less Than Significant Impact No Impact CITY OF SAN LUIS OBISPO INITIAL STUDY ENVIRONMENTAL CHECKLIST 2017 Evaluation: a) b) c) d) e) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. No specific site is under consideration. Conclusion: The project will have no impact on air quality. 4. BIOLOGICAL RESOURCES. Would the project: a) Have a substantial adverse effect, either directly or through habitat modifications, on any species identified as a candidate, sensitive, or special status species in local or regional plans, policies, or regulations, or by the California Department of Fish and Game or U.S. Fish and Wildlife Service? X b) Have a substantial adverse effect, on any riparian habitat or other sensitive natural community identified in local or regional plans, policies, or regulations, or by the California Department of Fish and Game or U.S. Fish and Wildlife Service? X c) Have a substantial adverse effect on federally protected wetlands as defined in Section 404 of the Clean Water Act (including, but not limited to, marsh, vernal pool, coastal, etc.) through direct removal, filling, hydrological interruption, or other means? X d) Interfere substantially with the movement of any native resident or migratory fish or wildlife species or with established native resident or migratory wildlife corridors, or impede the use of native wildlife nursery sites? X e) Conflict with any local policies or ordinances protecting biological resources, such as a tree preservation policy or ordinance? X f) Conflict with the provisions of an adopted habitat Conservation Plan, Natural Community Conservation Plan, or other approved local, regional, or state habitat conservation plan? X Evaluation: a) b) c) d) e) f) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. No specific site is under consideration. Conclusion: The project will have no impact on biological resources. 5. CULTURAL RESOURCES. Would the project: a) Cause a substantial adverse change in the significance of a historic resource as defined in §15064.5. X b) Cause a substantial adverse change in the significance of an archaeological resource pursuant to §15064.5) X c) Directly or indirectly destroy a unique paleontological resource or site or unique geologic feature? X d) Disturb any human remains, including those interred outside of formal cemeteries? X Packet Pg 47 Issues, Discussion and Supporting Information Sources GPA 1454-2018 / EID 1455-2018 (2018 Amendment to General Plan, Chapter 8, Water and Wastewater Management Element) Sources Potentially Significant Issues Potentially Significant Unless Mitigation Incorporated Less Than Significant Impact No Impact CITY OF SAN LUIS OBISPO INITIAL STUDY ENVIRONMENTAL CHECKLIST 2017 Evaluation: a) b) c) d) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. No specific site is under consideration. Conclusion: The project will have no impact on cultural resources. 6. GEOLOGY AND SOILS. Would the project: a) Expose people or structures to potential substantial adverse effects, including the risk of loss, injury or death involving: X I. Rupture of a known earthquake fault, as delineated on the most recent Alquist-Priolo Earthquake Fault Zoning Map issued by the State Geologist for the area or based on other substantial evidence of a known fault? Refer to Division of Mines and Geology Special Publication 42. X II. Strong seismic ground shaking? X III. Seismic-related ground failure, including liquefaction? X IV. Landslides? X b) Result in substantial soil erosion or the loss of topsoil? X c) Be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project, and potentially result in on or off site landslide, lateral spreading, subsidence, liquefaction or collapse? X d) Be located on expansive soil, as defined in Table 1802.3.2 of the California Building Code (2013), creating substantial risks to life or property? X e) Have soils incapable of adequately supporting the use of septic tanks or alternative waste water disposal systems where sewers are not available for the disposal of waste water? X Evaluation: a) b) c) d) e) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. No specific site is under consideration. Conclusion: No Impact. 7. GREENHOUSE GAS EMISSIONS. Would the project: a) Generate greenhouse gas emissions, either directly or indirectly, that may have a significant impact on the environment? X b) Conflict with an applicable plan, policy or regulation adopted for the purpose of reducing the emissions of greenhouse gases? X Evaluation: a) b) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. No specific site is under consideration. The Water and Wastewater Management Element continues to support buildout consistent with the General Plan. Conclusion: No Impact. Packet Pg 48 Issues, Discussion and Supporting Information Sources GPA 1454-2018 / EID 1455-2018 (2018 Amendment to General Plan, Chapter 8, Water and Wastewater Management Element) Sources Potentially Significant Issues Potentially Significant Unless Mitigation Incorporated Less Than Significant Impact No Impact CITY OF SAN LUIS OBISPO INITIAL STUDY ENVIRONMENTAL CHECKLIST 2017 8. HAZARDS AND HAZARDOUS MATERIALS. Would the project: a) Create a significant hazard to the public or the environment through the routine transport, use, or disposal of hazardous materials? X b) Create a significant hazard to the public or the environment through reasonably foreseeable upset and accident conditions involving the release of hazardous materials into the environment? X c) Emit hazardous emissions or handle hazardous or acutely hazardous materials, substances, or waste within one-quarter mile of an existing or proposed school? X d) Be located on a site which is included on a list of hazardous materials sites compiled pursuant to Government Code Section 65962.5 and, as a result, would it create a significant hazard to the public or the environment? X e) For a project located within an airport land use plan or, where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project result in a safety hazard for people residing or working in the project area? X f) For a project within the vicinity of a private airstrip, would the project result in a safety hazard for people residing or working in the project area? X g) Impair implementation of or physically interfere with an adopted emergency response plan or emergency evacuation plan? X h) Expose people or structures to a significant risk of loss, injury, or death involving wildland fires, including where wildlands are adjacent to urbanized areas or where residences are intermixed with wildlands? X Evaluation: a) b) c) d) e) f) g) h) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. No specific site is under consideration. Conclusion: No Impact. 9. HYDROLOGY AND WATER QUALITY. Would the project: a) Violate any water quality standards or waste discharge requirements? X b) Substantially deplete groundwater supplies or interfere substantially with groundwater recharge such that there would be a net deficit in aquifer volume or a lowering of the local groundwater table level (e.g. the production rate of pre-existing nearby wells would drop to a level which would not support existing land uses or planned uses for which permits have been granted)? X c) Substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, in a manner which would result in substantial erosion or siltation on or off site? X d) Substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream X Packet Pg 49 Issues, Discussion and Supporting Information Sources GPA 1454-2018 / EID 1455-2018 (2018 Amendment to General Plan, Chapter 8, Water and Wastewater Management Element) Sources Potentially Significant Issues Potentially Significant Unless Mitigation Incorporated Less Than Significant Impact No Impact CITY OF SAN LUIS OBISPO INITIAL STUDY ENVIRONMENTAL CHECKLIST 2017 or river, or substantially increase the rate or amount of surface runoff in a manner which would result in flooding on or off site? e) Create or contribute runoff water which would exceed the capacity of existing or planned storm water drainage systems or provide substantial additional sources of polluted runoff? X f) Otherwise substantially degrade water quality? X g) Place housing within a 100-year flood hazard area as mapped on a federal Flood Hazard Boundary or Flood Insurance Rate Map or other flood hazard delineation map? X h) Place within a 100-year flood hazard area structures which would impede or redirect flood flows? X i) Expose people or structures to significant risk of loss, injury or death involving flooding, including flooding as a result of the failure of a levee or dam? X j) Inundation by seiche, tsunami, or mudflow? Evaluation: a) b) c) d) e) f) g) h) i) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. No specific site is under consideration. Conclusion: No Impact 10. LAND USE AND PLANNING. Would the project: a) Physically divide an established community? X b) Conflict with any applicable land use plan, policy, or regulation of an agency with jurisdiction over the project (including, but not limited to the general plan, specific plan, local coastal program, or zoning ordinance) adopted for the purpose of avoiding or mitigating an environmental effect? X c) Conflict with any applicable habitat conservation plan or natural community conservation plan? X Evaluation: a) b) c) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. No specific site is under consideration. The update is consistent with other elements of the City’s General Plan, will not conflict with adopted habitat conservation plans, an d will not divide and established community as no specific site is under consideration. Conclusion: No Impact. 11. MINERAL RESOURCES. Would the project: a) Result in the loss of availability of a known mineral resource that would be of value to the region and the residents of the state? X b) Result in the loss of availability of a locally-important mineral resource recovery site delineated on a local general plan, specific plan or other land use plan? X Packet Pg 50 Issues, Discussion and Supporting Information Sources GPA 1454-2018 / EID 1455-2018 (2018 Amendment to General Plan, Chapter 8, Water and Wastewater Management Element) Sources Potentially Significant Issues Potentially Significant Unless Mitigation Incorporated Less Than Significant Impact No Impact CITY OF SAN LUIS OBISPO INITIAL STUDY ENVIRONMENTAL CHECKLIST 2017 Evaluation: a) b) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. No specific site is under consideration. Conclusion: No impact. 12. NOISE. Would the project result in: a) Exposure of persons to or generation of noise levels in excess of standards established in the local general plan or noise ordinance, or applicable standards of other agencies? X b) Exposure of persons to or generation of excessive groundborne vibration or groundborne noise levels? X c) A substantial permanent increase in ambient noise levels in the project vicinity above levels existing without the project? X d) A substantial temporary or periodic increase in ambient noise levels in the project vicinity above levels existing without the project? X e) For a project located within an airport land use plan, or where such a plan has not been adopted, within two miles of a public airport or public use airport, would the project expose people residing or working in the project area to excessive noise levels? f) For a project within the vicinity of a private airstrip, would the project expose people residing or working in the project area to excessive noise levels? X X Evaluation: a) b) c) d) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. No specific site is under consideration. Conclusion: No Impact. 13. POPULATION AND HOUSING. Would the project: a) Induce substantial population growth in an area, either directly (for example, by proposing new homes and businesses) or indirectly (for example, through extension of roads or other infrastructure)? X b) Displace substantial numbers of existing housing, necessitating the construction of replacement housing elsewhere? c) Displace substantial numbers of people, necessitating the construction of replacement housing elsewhere? X X Packet Pg 51 Issues, Discussion and Supporting Information Sources GPA 1454-2018 / EID 1455-2018 (2018 Amendment to General Plan, Chapter 8, Water and Wastewater Management Element) Sources Potentially Significant Issues Potentially Significant Unless Mitigation Incorporated Less Than Significant Impact No Impact CITY OF SAN LUIS OBISPO INITIAL STUDY ENVIRONMENTAL CHECKLIST 2017 Evaluation: a) b) c) The 2018 amendment to the Water and Wastewater Management Element will not induce substantial population growth or displace existing housing or people. Growth supported by the goals, policies, and programs in the Water and Wastewater Management Element is growth that was envisioned and evaluated as part of the Land Use Element of the General Plan and subsequent specific plans for the expansion areas. Any use of water beyond General Plan build-out, requires that the current General Plan build-out be evaluated and modified first, based on its own merits and not driven or limited by water supply availability. Conclusion: No impact to population or housing will occur with the proposed project. 14. PUBLIC SERVICES. Would the project result in substantial adverse physical impacts associated with the provision of new or physically altered governmental facilities, the construction of which could cause significant environmental impacts, in order to maintain acceptable service ratios, response times or other performance objectives for any of the public services: a) Fire protection? X b) Police protection? X c) Schools? X d) Parks? X e) Other public facilities? X Evaluation: a) b) c) d) e) f) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. No specific site is under consideration. Conclusion: No impact. 15. RECREATION. a) Would the project increase the use of existing neighborhood or regional parks or other recreational facilities such that substantial physical deterioration of the facility would occur or be accelerated? X b) Does the project include recreational facilities or require the construction or expansion of recreational facilities which might have an adverse physical effect on the environment? X Evaluation: a) b) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. No specific site is under consideration. Conclusion: No impacts to recreation will occur as part of the proposed amendments. 16. TRANSPORTATION/TRAFFIC. Would the project: a) Conflict with an applicable plan, ordinance or policy establishing measures of effectiveness for the performance of the circulation system, taking into account all modes of transportation including mass transit and non-motorized travel and relevant components of the circulation system, including but not limited to intersections, streets, highways and freeways, pedestrian and bicycle paths, and mass transit? X b) Conflict with an applicable congestion management program, including, but not limited to level of service standards and travel X Packet Pg 52 Issues, Discussion and Supporting Information Sources GPA 1454-2018 / EID 1455-2018 (2018 Amendment to General Plan, Chapter 8, Water and Wastewater Management Element) Sources Potentially Significant Issues Potentially Significant Unless Mitigation Incorporated Less Than Significant Impact No Impact CITY OF SAN LUIS OBISPO INITIAL STUDY ENVIRONMENTAL CHECKLIST 2017 demand measures, or other standards established by the county congestion management agency for designated roads or highways? c) Result in a change in air traffic patterns, including either an increase in traffic levels or a change in location that results in substantial safety risks? X d) Substantially increase hazards due to a design feature (e.g., sharp curves or dangerous intersections) or incompatible uses (e.g. farm equipment)? X e) Result in inadequate emergency access? X f) Conflict with adopted policies, plans, or programs regarding public transit, bicycle, or pedestrian facilities, or otherwise decrease the performance or safety of such facilities? X Evaluation: a) b) c) d) e) f) g) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. No specific site is under consideration. Conclusion: No impacts to traffic or transportation are identified. 17. TRIBAL CULTURAL RESOURCES. Would the project cause a substantial adverse change in the significance of a tribal cultural resource, defined in Public Resources Code Section 21074 as either a site, feature, place, cultural landscape that is geographically defined in terms of the size and scope of the landscape, sacred place, or object with cultural value to a California Native American tribe, and that is: a) Listed or eligible for listing in the California Register of Historical Resources, or in a local register as defined in Public Resources Section 5020.1(k)? X b) A resource determined by the lead agency, in its discretion and supported by substantial evidence, to be significant pursuant to criteria set forth in subdivision (c) of Public Resources Code Section 5024.1? In applying the criteria set forth in subdivision (c) of Public Resources Code Section 5024.1, the lead agency shall consider the significance of the resource to a California Native American tribe. X Evaluation: On February 12, 2018, local Native American tribal groups that have a cultural and traditional affiliation to the area of the City of San Luis Obispo were formally noticed that an Initial Study of Environmental Review was being completed for the update to the City’s Water and Wastewater Management Element. None of the noticed Tribal Groups identified a Tribal Cultural Resource (TCR) on the site or requested consultation. a) b) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. No specific site is under consideration. No impacts to tribal cultural resources would occur. Conclusion: No impact. Packet Pg 53 Issues, Discussion and Supporting Information Sources GPA 1454-2018 / EID 1455-2018 (2018 Amendment to General Plan, Chapter 8, Water and Wastewater Management Element) Sources Potentially Significant Issues Potentially Significant Unless Mitigation Incorporated Less Than Significant Impact No Impact CITY OF SAN LUIS OBISPO INITIAL STUDY ENVIRONMENTAL CHECKLIST 2017 18. UTILITIES AND SERVICE SYSTEMS. Would the project: a) Exceed wastewater treatment requirements of the applicable Regional Water Quality Control Board? X b) Require or result in the construction or expansion of new water or wastewater treatment facilities or expansion of existing facilities, the construction of which could cause significant environmental effects? X c) Require or result in the construction of new storm water drainage facilities or expansion of existing facilities, the construction of which could cause significant environmental effects? X d) Have sufficient water supplies available to serve the project from existing entitlements and resources, or are new and expanded entitlements needed? X e) Result in a determination by the wastewater treatment provider which serves or may serve the project that it has adequate capacity to serve the project’s projected demand in addition to the provider’s existing commitments? X f) Be served by a landfill with sufficient permitted capacity to accommodate the project’s solid waste disposal needs? X g) Comply with federal, state, and local statutes and regulations related to solid waste? X Evaluation: a) b) c) d) e) f) g) The 2018 amendment to the Water and Wastewater Management Element updates water supply availability data from the City’s safe annual yield model for Whale Rock and Salinas Reservoirs. Wastewater background information is also updated. No changes are proposed to the City’s water and wastewater goals, policies, or programs. Water and wastewater service is intended to serve development under the General Plan. With the reduction in safe annual yield, the City continues to have an adequate water supply to meet projected water demand of 57,200 residents at 117 gpcd, a 20 percent reliability reserve, and over 1,000 acre feet as a secondary water supply. No specific site is under consideration. Development projects are evaluated more specifically for their potential impacts on utilities and service systems. Conclusion: No impacts have been identified relative to utilities or service systems. 19. MANDATORY FINDINGS OF SIGNIFICANCE. a) Does the project have the potential to degrade the quality of the environment, substantially reduce the habitat of a fish or wildlife species, cause a fish or wildlife population to drop below self-sustaining levels, threaten to eliminate a plant or animal community, reduce the number or restrict the range of a rare or endangered plant or animal or eliminate important examples of the major periods of California history or prehistory? X No significant impacts have been identified during the review of the2018 amendment to the Water and Wastewater Management Element. b) Does the project have impacts that are individually limited, but cumulatively considerable? ("Cumulatively considerable" means that the incremental effects of a project are considerable when viewed in connection with the effects of the past projects, the effects of other current projects, and the effects of probable future projects)? X There are no impacts identified in this Initial Study. Packet Pg 54 Issues, Discussion and Supporting Information Sources GPA 1454-2018 / EID 1455-2018 (2018 Amendment to General Plan, Chapter 8, Water and Wastewater Management Element) Sources Potentially Significant Issues Potentially Significant Unless Mitigation Incorporated Less Than Significant Impact No Impact CITY OF SAN LUIS OBISPO INITIAL STUDY ENVIRONMENTAL CHECKLIST 2017 c) Does the project have environmental effects which will cause substantial adverse effects on human beings, either directly or indirectly? X The 2018 amendment to the Water and Wastewater Management Element will not create environmental effects that will have an adverse impact on humans. 20. EARLIER ANALYSES. Earlier analysis may be used where, pursuant to the tiering, program EIR, or other CEQA process, one or more effects have been adequately analyzed in an earlier EIR or Negative Declaration. Section 15063 (c) (3) (D). In this case a discussion should identify the following items: a) Earlier analysis used. Identify earlier analyses and state where they are available for review. City of San Luis Obispo General Plan is available at the City Community Development Department (919 Palm Street, San Luis Obispo, CA 93401) and at the following website: http://www.slocity.org/government/department-directory/community-development/planning-zoning/general-plan b) Impacts adequately addressed. Identify which effects from the above checklist were within the scope of and adequately analyzed in an earlier document pursuant to applicable legal standards, and state whether such effects were addressed by mitigation measures based on the earlier analysis. N/A c) Mitigation measures. For effects that are "Less than Significant with Mitigation Incorporated," describe the mitigation measures which were incorporated or refined from the earlier document and the extent to which they address site-specific conditions of the project. N/A 21. SOURCE REFERENCES. 1. City of SLO General Plan Land Use Element, December 2014 and Final EIR, October 2014 2. City of SLO General Plan Circulation Element, December 2014 and Final EIR, October 2014 3. City of SLO General Plan Noise Element, May 1996 4. City of SLO General Plan Safety Element, March 2012 5. City of SLO General Plan Conservation & Open Space Element, April 2006 6. City of SLO General Plan Housing Element, January 2015 7. City of San Luis Obispo Municipal Code 8. City of SLO 2015 Urban Water Management Plan, June 2016 9. City of SLO, Final Potable Water Distribution System Operations Master Plan, December 2015 10. City of SLO, Wastewater Collection System Infrastructure Renewal Strategy, 2016 11. County of San Luis Obispo, Nacimiento Water Project Final Environmental Impact Report (SCH #2001061022), December 2003 and Addendum 2016 12. City of SLO, Sewer System Management Plan, 2014 13. City of SLO, Water Resource Recovery Facility Upgrade EIR (SCH #2015101044), 2016 14. City of SLO, Recycled Water Master Plan, 2017 15. Water Systems Consulting, Safe Annual Yield Model Update, Technical Memorandum to the City of San Luis Obispo, January 2018 Exhibit 1: Proposed Amendment to City of San Luis Obispo General Plan, Chapter 8. Water and Wastewater Management Element, March 2018. Packet Pg 55 ATTACHMENT 3 R ______ RESOLUTION NO. (2018 Series) A RESOLUTION OF THE PLANNING COMMISSION OF THE CITY OF SAN LUIS OBISPO RECOMMENDING THE CITY COUNCIL ADOPT AMENDMENTS TO THE WATER AND WASTEWATER MANAGEMENT ELEMENT OF THE GENERAL PLAN (GPA 1454-2018) AND ADOPT A NEGATIVE DECLARATION OF ENVIRONMENTAL IMPACT (EID 1455-2018) WHEREAS, State law requires cities and counties to adopt a general plan; and WHEREAS, the Water and Wastewater Management Element of the San Luis Obispo City General Plan was last updated in 2016 in compliance with State law; and WHEREAS, a periodic update of the Water and Wastewater Management Element is necessary for the information to remain current; and WHEREAS, the City of San Luis Obispo has prepared an updated Draft General Plan Water and Wastewater Management Element to address current information and long-term community-wide needs for water and wastewater treatment provision, and WHEREAS, the potential environmental impacts of the updated Water and Wastewater Management Element have been evaluated in accordance with the California Environmental Quality Act pursuant to an initial environmental study (EID 1455-2018) and the Community Development Director has prepared a negative declaration of environmental impact; and WHEREAS, the Planning Commission, at the hearing on April 11, 2018, considered the amendments to the General Plan Water and Wastewater Management Element as shown in the Draft Water and Wastewater Management Element and proposed Negative Declaration of Environmental Effect. NOW, THEREFORE, BE IT RESOLVED by the Planning Commission of the City of San Luis Obispo as follows: SECTION 1. Findings. The Planning Commission, after considering the proposed amendments to the Water and Wastewater Management Element, environmental determination, staff recommendations, public testimony and correspondence, and reports thereon, makes the following findings: 1. The proposed amendments, contained in the draft Water and Wastewater Management Element Update are consistent with the General Plan. SECTION 2. Environmental Determination. The Planning Commission recommends the City Council determine that the proposed General Plan Water and Wastewater Management Element amendments will not create a substantial environmental effect as defined by the California Environmental Quality Act and supports the initial environmental study (EID 1455-2018) and associated Negative Declaration prepared by the Community Development Director. Upon motion of _______________________, seconded by _______________________, and on the following roll call vote: Packet Pg 56 Resolution No. (2018 Series) Page 2 AYES: NOES: ABSENT: The foregoing resolution was adopted this 11th day of April 2018. Packet Pg 57 Technical Memorandum       City SAY Model Update TM    Date:  1/8/2018  To:  Mr. Aaron Floyd   City of San Luis Obispo – Public Utilities     San Luis Obispo, California    Prepared by: Adam Rianda, P.E.  Reviewed by: Jeroen Olthof, P.E.  Project: Safe Annual Yield Analysis Update  SUBJECT: SALINAS AND WHALE ROCK RESERVOIRS SAFE ANNUAL YIELD      Section 1: Background The City of San Luis Obispo (City) maintains a diversified portfolio of water supply sources that it can use to meet  potable water demand.  Two of these sources are Salinas Reservoir, also known as Santa Margarita Lake, and  Whale Rock Reservoir, located near the town of Cayucos.  Whale Rock Reservoir is a shared‐use reservoir serving  the City, the California Polytechnic State University (Cal Poly), the California Men’s Colony (CMC), and the town  of Cayucos. The City, Cal Poly, and CMC comprise the Whale Rock Commission, which governs reservoir  operation.  Some characteristics of the two reservoirs are shown in Table 1.  Table 1. Reservoir Attributes Reservoir Watershed Size  (Square Miles)  Storage Capacity  (Acre Feet)  Average Annual  Precipitation  (Inches)1  Average Annual  Evaporation  (Inches)1  Salinas 112.0 23,843 22.1 85.4  Whale Rock 20.3 38,967 18.7 61.6  1Average annual precipitation and evaporation depths are based on the verified hydrologic data discussed in Section 2.    Salinas Reservoir and Whale Rock Reservoir are located in different climate regions and have differing  characteristics.  Whale Rock Reservoir has a larger storage volume than Salinas, but it has a smaller watershed to  provide natural recharge.  Salinas Reservoir receives more runoff each year, but it also experiences higher  temperatures and higher evaporation rates, and it spills more frequently.  To maximize the available supply from  these two reservoirs, the City has developed operational strategies that recognize the differences between the  reservoirs.  In general, the strategies involve withdrawing water from Salinas Reservoir when it is available, and  using Whale Rock Reservoir as‐needed to supplement the supply from Salinas.  To assist with the management of the City’s water resources and understand the available supply from Salinas  and Whale Rock Reservoirs, the City maintains an Excel‐based model that estimates a safe annual yield (SAY)  based on historical climatic conditions and reservoir operations.  For each reservoir, the model sums the inputs  and outputs to calculate the reservoir volume on a monthly time step.  As inputs, the model uses the historical  Packet Pg 58 Safe Annual Yield Analysis Update   Salinas and Whale Rock Reservoirs Safe Annual Yield  1/8/2018                                                                                                                                                                                     Page 2  City SAY Model Update TM  record of inflows, evaporation, precipitation, and downstream releases.  The model then calculates, over the  period of record, the maximum amount that could be withdrawn each year without drawing the reservoir below  its minimum pool constraint.  This maximum allowable annual withdrawal is considered to be the SAY.  The City’s Excel‐based model of the two reservoirs was first developed in 1988.  At that time, the critical drought  period that controlled the SAY was the 1946‐1951 drought.  In 1991 the model was updated to incorporate the  hydrologic conditions experienced during the 1986‐1991 drought.  That drought was the most severe in the  historical record to that point and became the new controlling condition for estimating SAY.  The City estimated  the combined SAY from the two reservoirs as 6,940 acre‐feet per year (AFY).  This estimate included the  anticipated loss of storage volume due to siltation through the year 2010.  This estimate has been reported in  previous City planning documents, including the 2015 Urban Water Management Plan (UWMP) and the 2016  update to the General Plan Water and Wastewater Management Element.  The 2015 UWMP, published in June  of 2016, was prepared during a period of extended drought, and it noted that the City planned to re‐calculate  the SAY when the on‐going drought came to an end.  During the winter of 2016‐2017, California received enough precipitation to provide some drought relief, and  the Department of Water Resources phased out its mandatory conservation guidelines.  However, the state is  still in a period of below‐average precipitation.  Figure 1 shows historical precipitation recorded at Salinas and  Whale Rock Reservoirs.  For each month, the graph shows the average precipitation for the previous five‐year  period.  This rolling five‐year average can be compared to the long‐term average, in this case the period from  1962 to 2016.  The 1986‐1991 drought was preceded by a period of above‐average rainfall, and when the  drought ended the subsequent years had above‐average rainfall.  By contrast, the current dry period has had a  much longer duration.  Since 2003, the rolling average has been at or below the long‐term average, and at the  end of 2016 the rolling average reached the lowest value ever at Whale Rock.  It remains to be seen whether  future years will bring enough precipitation to bring the rolling five‐year average back to its historical levels.    Packet Pg 59 Safe Annual Yield Analysis Update   Salinas and Whale Rock Reservoirs Safe Annual Yield  1/8/2018                                                                                                                                                                                     Page 3  City SAY Model Update TM    Figure 1. Rolling Five-Year Average Precipitation at Salinas and Whale Rock   In early 2017, the City contracted with Water Systems Consulting, Inc. (WSC) to update the SAY model.  The  update was intended to verify the historical input data, validate and document the calculations in the model,  incorporate the full extent of the 2006‐2016 drought, and generate scenarios that accounted for potential  climate change impacts.  Section 2: Model Updates In January 2017, the City and Cal Poly began an update of the SAY model.  Two major objectives of the project  were to update and verify the hydrologic input data and to develop scenarios that accounted for climate change  impacts.  The SAY model was last updated in early 2015; therefore, the model that was used as the starting point  for this project is referred to as the 2015 model.  Verification of Input Data and Extension of Input Data Through January 2017 The 2015 model contained hydrologic input data for Whale Rock Reservoir and Salinas Reservoir through  February of 2015. While this data set contained values beginning in October of 1943, the source of the data had  not been documented.  Furthermore, the construction of Whale Rock Reservoir was not completed until April of  1961, so there was nearly 18 years of data that predated the reservoir.  According to the City’s records, the  (30.0) (20.0) (10.0) 0.0 10.0 20.0 30.0 0.0 10.0 20.0 30.0 40.0 50.0 60.0 Annual Inches of Rain at Whale RockAnnual Inches of Rain at Salinas                                          .  Salinas Rolling Five‐Year Average Salinas Average 1962 ‐ 2016 Whale Rock Rolling Five‐Year Average Whale Rock Average 1962 ‐ 2016 Packet Pg 60 Safe Annual Yield Analysis Update   Salinas and Whale Rock Reservoirs Safe Annual Yield  1/8/2018                                                                                                                                                                                     Page 4  City SAY Model Update TM  hydrologic data predating the reservoir was generated through correlations between Salinas and Whale Rock  Reservoir lake levels and precipitation.   In order to load the model with verified historical hydrologic data, the City compiled the information that could  be traced to verified sources. Table 2 presents the data sets collected for this update as well as the start date of  each data series.  All data sets were compiled through January of 2017, when the drought of 2006‐2016 had  subsided.  Table 2. Verified Hydrologic Data Start Date Reservoir Precipitation Evaporation Inflow1 Downstream Releases  Salinas 7/1/1948 7/1/1970 4/1/1942 7/1/1942  Whale Rock 1/1/1962 10/1/1963 2/1/1962 2/1/1962  1Inflow for Whale Rock Reservoir calculated by Damsaver begins 6/1/1987. Inflow from 1962 to 1987 was calculated using paper records  compiled by City staff.     The inflow data for Whale Rock Reservoir came from two sources:  Damsaver and paper records.  Damsaver is  an Excel‐based tool that the City began to use in June 1987 to record and report Whale Rock Reservoir  hydrologic data, including the computation of monthly inflow. Prior to 1987, the City utilized a paper form to  record monthly precipitation, evaporation, reservoir elevation, reservoir storage, and water releases. To  generate a complete data set extending back to 1962, WSC performed mass balance1 calculations using data  from the paper records. The calculated inflows were validated using a 2.5‐year overlap period, 1987 to 1989,  when the City utilized both Damsaver and the paper forms. While there was variation from month to month, the  total calculated inflows over the 2.5‐year period were within 10 percent of the total produced using the  Damsaver software. Therefore, the pre‐1987 inflows calculated from the paper forms were considered  acceptable for use in this evaluation.  In general, the verified historical data compiled for this update was not significantly different than the input data  in the 2015 model.  The exception was in recorded evaporation rates.  For this update, historical evaporation  data was available for the period beginning July 1, 1970.  The historical data in the previous model and the data  compiled for this study are shown in Figure 2 and Figure 3.                                                                 1 The mass balance calculation was based on the fact that monthly change in storage volume will be determined by the  inputs (precipitation and inflow) and outputs (evaporation and downstream releases) during that month.  Historical data for  reservoir levels were used to calculate change in storage, and historical data was available for precipitation, evaporation,  and downstream releases.  The team then solved for the only unknown variable, monthly inflow.  Packet Pg 61 Safe Annual Yield Analysis Update   Salinas and Whale Rock Reservoirs Safe Annual Yield  1/8/2018                                                                                                                                                                                     Page 5  City SAY Model Update TM    Figure 2. Cumulative Evaporation Data for Salinas Reservoir, 1970-2015     Figure 3. Cumulative Evaporation Data for Whale Rock Reservoir, 1970-2015 For both reservoirs, the updated historical data show consistently higher evaporation rates than the data used in  the 2015 model.  The difference results in evaporation losses approximately 30 percent higher than the 2015  model, leading to a reduction in the calculated SAY.  Climate Change Impacts Although previous versions of the model included several scenarios with adjusted climatic patterns, they were  based on simple modifications to relatively short data sets. As part of this model update, a range of new  scenarios was added based on varying climate change projections identified by the U.S. Environmental  Protection Agency (EPA) and the San Luis Obispo Council of Governments (SLOCOG). The estimated changes in  climate associated with these scenarios were applied to the historical data set for inflows, precipitation, and  evaporation.  The model was then used to calculate a revised SAY assuming that these conditions had prevailed  during the historical period of record.   ‐  500  1,000  1,500  2,000  2,500  3,000  3,500  4,000  4,500 1970 1975 1981 1986 1992 1997 2003 2008 2014Cumulative Evaporation (inches)Salinas Cumulative Evaporation, Previous Model (inches) Salinas Cumulative Evaporation, Verified Historical Data (inches)  ‐  500  1,000  1,500  2,000  2,500  3,000 1970 1975 1981 1986 1992 1997 2003 2008 2014Cumulative Evaporation (inches)Whale Rock Cumulative Evaporation, Previous Model (inches) Whale Rock Cumulative Evaporation, Verified Historical Data (inches) Packet Pg 62 Safe Annual Yield Analysis Update   Salinas and Whale Rock Reservoirs Safe Annual Yield  1/8/2018                                                                                                                                                                                     Page 6  City SAY Model Update TM  Section 3: Scenario Modeling Scenario 1: 2015 Model Scenario 1 runs the model using the hydrologic input data used in the 2015 model. As discussed previously, the  source of this hydrologic input data was not documented.  Scenario 2: Verified Historical Data Scenario 2 utilizes the historical hydrological data set compiled for this update.  Because this input data has been  verified against historical records, Scenario 2 is considered to be the baseline estimate for future conditions.  Scenarios 3 through 8: EPA CREAT Climate Change Projections Scenarios 3 through 8 are based on climate change projections identified in the EPA’s Climate Resilience  Evaluation and Awareness (CREAT) Projection Map. CREAT was prepared by the EPA, specifically for drinking  water, wastewater and stormwater utility owners and operators, as an informational tool to assist in  understanding and addressing climate change risks. Projected changes in CREAT were derived from the  evaluation of thirty‐eight Global Climate Models recognized by the Intergovernmental Panel on Climate Change  (IPCC). Results from each model were recorded on a 0.5‐ by 0.5‐degree (approximately 34‐ by 34‐mile) grid basis  and compared to three statistical targets based on the distribution of the models. The five models closest to  each target were averaged to generate each projected temperature and precipitation change. The three targets  are defined as:   Hot/dry future conditions – Nearest to the 5th percentile of precipitation and 95th percentile of  temperature projections;   Central future conditions – Nearest to the 50th percentile of both precipitation and temperature  projections; and   Warm/wet conditions – Nearest to the 95th percentile of precipitation and 5th percentile of temperature  projections.  Projections are presented for two planning horizons:  2035, the midpoint of a range from 2024 to 2045, and  2060, the midpoint of a range from 2050 to 2070.  For the SAY model, it is assumed that the change in inflow is directly proportional to the change in precipitation.   Because of the uncertainty about the exact relationship between higher temperatures and increased  evaporation, future evaporation rates were assumed to be five percent higher than the verified historical data.  Projected changes are applied to the entire verified historical data set in Scenario 2.  Scenarios 9 through 12: SLOCOG Climate Change Projections Scenarios 9 through 12 are based on climate change projections identified in the San Luis Obispo Council of  Governments (SLOCOG) 2014 Regional Transportation Plan. SLOCOG climate change projections reflect the  continuation of current energy‐subsidy policies, implying relatively high energy consumption and high  greenhouse gas (GHG) emissions. Per the SLOCOG report, this scenario closely followed the global emissions  path of the late 1990s. The SLOCOG report states that given a sharp rise in emissions since 2000, the climate  projections reflected may underestimate actual climate change.  Packet Pg 63 Safe Annual Yield Analysis Update   Salinas and Whale Rock Reservoirs Safe Annual Yield  1/8/2018                                                                                                                                                                                     Page 7  City SAY Model Update TM  Like EPA’s CREAT tool, the SLOCOG projections are based on IPCC recognized Global Climate Models.  However,  the SLOCOG study focuses specifically on three models:  CSIRO (from Australia), MIROC (from Japan), and  HadCM (from the UK). The United States Department of Agriculture (USDA) Forest Service Mapped Atmosphere‐ Plant‐Soil System (MAPSS) team at the Pacific Northwest Research Station then converted the model output to a  locally‐relevant scale of 8 kilometers (km) using local temperature and precipitation pattern data.  As with the EPA CREAT projections, SLOCOG projections are presented as a percent difference in precipitation  and degree difference in temperature, and are assigned to two planning horizons, 2035 to 2045 and 2075 to  2085. The SLOCOG projections, however, are presented as a range for each window of time. Therefore, a  scenario was created for the climatic lower bound and upper bound for each planning horizon.  As with Scenarios 3 through 8, Scenarios 9 through 12 apply the respective climate change projections to the  verified historical data set (Scenario 2) and adjust the inflow proportionally to the change in precipitation, while  evaporation rates were assumed to be five percent higher than historical values.   Scenario 13: Nature Climate Change Evaluation Nature Communications, a peer‐reviewed open access scientific journal published by the Nature Publishing  Group, published an article in in July of 2017 that presented an overview of various climate models and their  predictions for future precipitation in California.  This work found that under future conditions, California could  receive more precipitation in response to global warming.  It found that the anticipated changes in air circulation  patterns were reminiscent of an El Nino event, which can lead to an increase in storm track activity in the east  Pacific.  The article concluded that central California could expect on the order of three inches per year in additional  rainfall attributable to global warming.  The historical average annual rainfall at Salinas Dam is approximately 23  inches, while the annual average at Whale Rock Reservoir is approximately 19 inches.  As a conservative  estimate, it was assumed that under this scenario, precipitation and runoff values would increase 15 percent  over their historical values.  Evaporation rates were assumed to be 5 percent higher than historical values.  Section 4: Model Results The updated spreadsheet model is intended to be a tool that the City can use to evaluate SAY under potential  future conditions.  Several simulations were run during the development of the spreadsheet, and the results are  summarized in the following tables.  These preliminary results are intended to show the range of potential  values under differing input assumptions. As discussed further in the Appendix, the model is set up to account  for loss of reservoir capacity due to siltation up to, and including, the designated simulation year. The model  results presented in Tables 3 through 5 account for the estimated siltation through 2017.   The model was first used to determine the impact of using verified historical data as inputs.  The results are  summarized in Table 3.  For consistency with previous estimates, these results do not include the 2006 ‐ 2016  drought.  These results are presented for comparison with previously reported values of SAY.  Using the raw  input data from the 2015 model, the updated model showed that an annual withdrawal of 6,940 AFY could be  sustained.  With the incorporation of the updated evaporation data, the corresponding value is 6,590 AFY.    Packet Pg 64 Safe Annual Yield Analysis Update   Salinas and Whale Rock Reservoirs Safe Annual Yield  1/8/2018                                                                                                                                                                                     Page 8  City SAY Model Update TM  Table 3. Safe Annual Yield Model Outputs with Verified Historical Data  2015 Model SAY  (AFY)  Updated Model SAY with Verified  Historical Data (AFY)  SAY (Period of record ending 2006; does not  include the 2006‐2016 drought)  6,940 6,590  Note:  These results are the combined City SAY from Salinas and Whale Rock Reservoirs, based on a  joint operating strategy    The model was then used to calculate an updated SAY for the entire period of record, including the 2006 – 2016  drought.  These results are shown in Table 4.  This drought was more severe than the 1986‐1991 drought, and it  has become the new controlling condition for the estimation of SAY.  The estimated SAY is 4,910 AFY,  approximately 2,000 AFY less than the previously used estimate of 6,940 AFY.  Table 4. Safe Annual Yield Model Outputs Incorporating 2006 – 2016 Drought  Updated Model SAY with Verified  Historical Data (AFY)  SAY (Period of record through 2016; includes the 2006‐2016  drought)  4,910  Note:  These results are the combined City SAY from Salinas and Whale Rock Reservoirs, based on a  joint operating strategy    Finally, the model was used to simulate a range of potential climate change scenarios.  These estimates are  summarized in Table 5.  There is considerable uncertainty about how climate change will impact the  precipitation and evaporation patterns on the Central Coast.  The range of values provides an indication of  potential future conditions that might occur, but it is not yet feasible to identify an expected value for future  SAY.  Table 5. Safe Annual Yield Model Outputs for Climate Change Scenarios       Range of SAY  under EPA  Climate Change  Scenarios (AFY)  Range of SAY  under SLOCOG  Climate Change  Scenarios (AFY)  Nature Climate  Change  Scenario (AFY)  SAY (Period of record through 2016; includes the  2006‐2016 drought)  4,690 – 5,050 4,050 – 5,070 4,950  Note:  These results are the combined City SAY from Salinas and Whale Rock Reservoirs, based on a joint  operating strategy       Packet Pg 65 Safe Annual Yield Analysis Update   Salinas and Whale Rock Reservoirs Safe Annual Yield  1/8/2018                                                                                                                                                                                     Page 9  City SAY Model Update TM    Section 5: Conclusion The City’s spreadsheet model for estimating SAY from Salinas and Whale Rock Reservoirs was updated to  incorporate verified historical data and the full extent of the most recent drought (2006 – 2016).  The revised  estimate for the SAY from these reservoirs is 4,910 AFY, approximately 2,000 AFY less than the value of 6,940  AFY used in previous planning documents.  Two factors contributed to this decline.  First, the historic  evaporation data in the model were revised to match currently available records.  Second, the updated model  includes the full extent of the 2006‐2016 drought.  This dry period was more severe than the 1986‐1991  drought, and it is the new controlling period for estimating SAY.  The updated spreadsheet model can be used to estimate the SAY under a variety of scenarios.  The spreadsheet  can also be used to demonstrate the advantages of coordinating the use of the City’s water supply sources,  rather than analyzing each source in isolation.  It is recommended that the City and Cal Poly continue to  coordinate their analyses of the expected supply from Whale Rock.  The model should also be kept up‐to‐date  with additional hydrological data, as it becomes available.    Packet Pg 66        City SAY Model Update TM    Appendix A: Model Layout The updated model has been restructured to provide a more user‐friendly and transparent interface. This  appendix briefly describes key tabs in the spreadsheet model.  Dashboard Tab The primary components of the Dashboard tab, circled in blue in Figure A‐1, are the Modeled Scenario  dropdown list, the City Withdrawal Mode selection, and the Solve buttons. The Modeled Scenario dropdown list  allows the user to select the scenario of interest. The City Withdrawal Mode allows the user to calculate  separate SAY’s for Salinas and Whale Rock Reservoir, or to model them as joint, or coordinated, use. When Joint  Use is selected, the model prioritizes withdrawal from Salinas Reservoir and provides a single SAY for the two  reservoirs. The Solve buttons allow the user to run the model without having to manually iterate to the desired  solution. The Solve buttons count down the SAY from 100,000 AFY until the total unmet demand is equal to zero  over the entire time series.   Just above the Modeled Scenario dropdown list is a summary of assumptions and input data. These assumptions  and inputs have been discussed with the City and Cal Poly, and therefore likely will not change on a regular  basis, but they should always be reviewed prior to a model run.    Figure A-1. Dashboard Tab Screenshot   Packet Pg 67 Safe Annual Yield Analysis Update   Salinas and Whale Rock Reservoirs Safe Annual Yield  1/8/2018                                                                                                                                                                                 Page A‐2   City SAY Model Update TM  Scenario Tab As discussed in Section 2, a suite of new scenarios has been incorporated into the updated model. All scenarios  are defined on the Scenarios tab, including the scenario number and respective percent change in inflow,  precipitation, and evaporation. While a temperature change in degrees Fahrenheit is listed, it is not currently  being included in the calculations. All future scenarios are expected to have higher temperatures, which will lead  to increased evaporation, but there is uncertainty about how much evaporation will increase. In addition to  defining the scenario criteria, this tab is used to manually record the calculated SAY for each scenario.  Bathymetry Tab The Bathymetry tab houses the stage‐storage‐area relationships for the two reservoirs.  For Salinas Reservoir,  the relationship is based on the Salinas Reservoir Bathymetric survey conducted in 1990. The annual siltation  was estimated to reduce available storage in Salinas Reservoir by 40 AFY, based on the 1990 bathymetric survey.  For Whale Rock Reservoir, the relationship is based on the Whale Rock Reservoir Bathymetry survey conducted  in 2013. As part of the 2013 bathymetric survey, the annual siltation was estimated to reduce available storage  by 32.6 AFY. These siltation rates can be found on the Dashboard tab along with the year of the associated  bathymetric survey.  The user can select a year to run the simulation, and the model will reduce the full capacity of each reservoir to  account for the expected siltation between the date of the respective bathymetric survey and the simulation  year.  The City’s water supply planning policy already includes an expected reduction in future water supply of  500 AFY to account for reservoir siltation.  Therefore, the model simulations run for this project used a  simulation year of 2017 to estimate the SAY under current conditions.  Demand Patterns Tab The Demand Patterns tab defines the monthly demand multipliers for the City, Cal Poly, CMC, and Cayucos  water deliveries.  For the updated model, the City demand pattern has remained the same as in the previous  model.  The State demand pattern has been split into two new Cal Poly demand patterns, domestic and  agricultural, and an evenly distributed demand pattern for the CMC.  Cal Poly provided domestic and agricultural  usage data from 1992 through 2016, which was used to refine the Cal Poly demand patterns.  The demand  patterns are shown in Figure A‐2.  Packet Pg 68 Safe Annual Yield Analysis Update   Salinas and Whale Rock Reservoirs Safe Annual Yield  1/8/2018                                                                                                                                                                                 Page A‐3   City SAY Model Update TM    Figure A-2. Demand Patterns Calculations Tab The Calculations tab has inputs and formulas organized in a progression from left to right, with one row for  every month. Row 7 on the Calculations tab defines whether a column is an input value or a formula. Input  values are historical monthly hydrologic inputs including natural inflow volume, precipitation depth, and  evaporation depth. Input values should be added to the model as new data is collected over time. As input  values are added, the remainder of the cells in that row should be populated by dragging down the formulas  from the cell above.  Column Descriptions Tab This tab contains descriptions for each column on the Calculations tab. Column descriptions include a written  description and a display of the respective formula.  This tab provides more detailed information about the  calculations embedded in the spreadsheet.    0.00% 2.00% 4.00% 6.00% 8.00% 10.00% 12.00% 14.00% 16.00% 18.00% 123456789101112Monthly Demand MultiplierMonth City Monthly Demand Multiplier Cayucos Deliveries Monthly Demand Multiplier Cal Poly AG Monthly Demand Multiplier Cal Poly Domestic Monthly Demand Multiplier CMC Monthly Demand Multiplier Packet Pg 69