Appendix 4.15-1 Water Supply Assessment
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DIRECTORS 43885 SOUTH GRIMMER BOULEVARD • FREMONT, CALIFORNIA 94538 MANAGEMENT (510) 668-4200 • FAX (510) 770-1793 • www.acwd.org ROBERT AZIZ AKBARI SHAVER General Manager JAMES G. GUNTHER KURT ARENDS JUDY C. HUANG Operations and Maintenance PAULSETHY LAURA J. HIDAS JOHN H. WEED Water Resources ED STEVENSON June 24, 2020 Engineering and Technology Services JONATHAN WUNDERLICH Finance VIA ELECTRONIC MAIL Carmela Campbell ([email protected]) Economic and Community Development Director City of Union City 34009 Alvarado-Niles Road Union City, CA 94587
Dear Ms. Campbell:
Subject: Water Supply Assessment for Station East Project
As requested by the City of Union City, Alameda County Water District (ACWD) has prepared a water supply assessment for the Station East Project (enclosed). The water supply assessment was adopted by the ACWD Board of Directors on June 11, 2020 (resolution enclosed).
The water supply assessment was prepared pursuant to California Water Code Section §10910 which requires that a water supply assessment be provided to cities or counties for a project that is subject to the California Environmental Quality Act (CEQA), and which surpasses a threshold for the number of housing units and/or square feet of commercial/industrial buildings. The water supply assessment documents sources of water supply, quantifies water demands, evaluates drought impacts, and provides a comparison of water supply and demand that is the basis for an assessment of water supply sufficiency. The water supply assessment also includes provisions for Water Conservation to be implemented by the Project applicant. As noted in the assessment, these provisions will be a condition of water service to the Project.
Please contact Thomas Niesar, ACWD's Water Supply & Planning Manager, at (510) 668-6549 or e-mail [email protected], with any questions regarding this assessment.
Sincerely,
Robert Shaver General Manager
db/cs Attachments By E-mail cc: Leslie Carmichael, City of Union City ([email protected]) Devon Becker, ACWD ([email protected]) Thomas Niesar, ACWD ([email protected]) Laura Hidas, ACWD ([email protected])
0 RECYCLED PAPER
RESOLUTION NO. 20-042
OF BOARD OF DIRECTORS OF ALAMEDA COUNTY WATER DISTRICT APPROVING THE JUNE 2020 WATER SUPPLY ASSESSMENT FOR THE STATION EAST PROJECT
WHEREAS, California Water Code Section 10910 requires that a city or county that receives an application for a project that is subject to the California Environmental Quality Act (CEQA), and that exceeds a threshold for the number of housing units and/or square feet of commercial/industrial building area request the public water system that would supply water to the project to provide a water supply assessment;
WHEREAS, the City of Union City (City) has submitted the Station East Project (Project) that will allow for the construction of up to 964 multifamily residential units, 31,020 square feet of commercial space, and approximately 376,358 square feet of landscaped areas, including public parks and paseos, semi-private and private open space areas, and other landscaped areas;
WHEREAS, the Project exceeds the statutory thresholds;
WHEREAS, on February 18, 2020, the Alameda County Water District (District) received a request from the City to prepare a water supply assessment for the Project;
WHEREAS, on April 21, 2020, the District issued a request for extension from the City to extend the WSA completion period for an additional 30 days;
WHEREAS, staff has prepared a water supply assessment for the Project which includes a water supply and demand comparison under a range of hydrologic conditions;
WHEREAS, Water Code Section 10910 requires the District’s Board of Directors to approve the water supply assessment.
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NOW, THEREFORE, BE IT RESOLVED by the Board of Directors of the Alameda County
Water District that the June 2020 Station East Project Water Supply Assessment is hereby approved and the General Manager is authorized and directed to submit it to the City of Union City.
PASSED AND ADOPTED this 11th day of June 2020, by the following vote:
AYES: Directors Akbari, Gunther, Sethy, Weed, and Huang
NOES: None
ABSENT: None
/s/ JUDY C. HUANG Judy C. Huang, President Board of Directors Alameda County Water District
ATTEST: APPROVED AS TO FORM:
/s/ ANDREW WARREN /s/ PATRICK T. MIYAKI Andrew Warren, Assistant District Secretary Patrick T. Miyaki, General Counsel Alameda County Water District Alameda County Water District (Seal)
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CERTIFICATE
I, the undersigned District Secretary of ALAMEDA COUNTY WATER DISTRICT, do hereby certify that the foregoing is a full, true and correct copy of a Resolution of the Board of Directors of ALAMEDA COUNTY WATER DISTRICT, a political subdivision, which said Resolution was duly adopted at a meeting of said Board regularly, held on June 11, 2020, that a copy of said Resolution was forthwith duly entered in the minutes of said meeting of said Board, and that the same is in full force and effect.
Dated: June 24, 2020
Gina Markou, District Secretary Alameda County Water District
WATER SUPPLY ASSESSMENT
FOR THE
STATION EAST PROJECT
JUNE 2020
PREPARED FOR
CITY OF UNION CITY, CALIFORNIA
Prepared by:
ALAMEDA COUNTY WATER DISTRICT 43885 S. Grimmer Blvd. Fremont, CA 94538
Table of Contents INTRODUCTION 4 BACKGROUND 4 PURPOSE 4 METHODOLOGY 5 WATER DEMAND 6 WATER USE CATEGORIES 6 HISTORICAL AND CURRENT WATER USE 6 WATER DEMANDS - ACWD SERVICE AREA 7 WATER DEMANDS – STATION EAST PROJECT 8 Estimation of Project Water Demands 8 Water Efficiency Measures to be Incorporated in the Project 9 IMPACTS OF DROUGHT ON DEMANDS 9 WATER SUPPLY 11 WHOLESALE WATER SUPPLIES 11 State Water Project 11 San Francisco’s Regional Water System 12 LOCAL SOURCES 13 Niles Cone Groundwater Basin 13 Brackish Groundwater Desalination 14 Del Valle Reservoir 14 Recycled Water 14 WATER SUPPLY UNCERTAINTIES 15 Climate Change 15 Bay Delta Water Quality Control Plan Update 18 Local Supplies 18 San Francisco Regional Supplies 19 State Water Project Supplies 19 Semitropic Banking Program 21 SB 7 – Water Conservation Requirements under the 2009 Comprehensive Water Package 21 AB 1668 and SB 606 – Making Water Conservation a California Way of Life 22
i WATER SUPPLY IN NORMAL AND DRY YEAR CONDITIONS 22 Water Supply under Normal Year Conditions 22 Water Supply under Critical Dry Year Conditions 23 WATER SUPPLY AND DEMAND ANALYSES 24 NORMAL YEAR WATER SUPPLY 24 SINGLE DRY YEAR WATER SUPPLY 24 MULTIPLE DRY YEAR WATER SUPPLY 24 SUMMARY AND CONCLUSIONS 25 Multi-Family Residential Units 31 SUPPLY COMPONENT 36 Imported Supplies 36 Total Imported Supplies 36 Local Supplies 36 Total Local Supplies 36 Banking/Transfers 36 SUPPLY COMPONENT 36 Imported Supplies 36 Total Imported Supplies 36 Local Supplies 36 Total Local Supplies 36 Banking/Transfers 36 SUPPLY COMPONENT 37 Imported Supplies 37 Total Imported Supplies 37 Local Supplies 37 Total Local Supplies 37 Banking/Transfers 37
ATTACHMENT A – LETTER OF REQUEST FROM CITY OF UNION CITY FOR WATER SUPPLY ASSESSMENT AND LETTER OF REQUEST FROM ACWD FOR 30-DAY EXTENSION TO COMPLETE WATER SUPPLY ASSESSMENT
ii ATTACHMENT B – ACWD URBAN WATER MANAGEMENT PLAN 2015-2020
ATTACHMENT C – ACWD WATER SUPPLY CONTRACTS
ATTACHMENT D – ACWD RECOMMENDED WATER EFFICIENCY MEASURES
LIST OF TABLES
Table 1 ACWD Past and Current Water Use (Acre-Feet) ...... 27 Table 2 Estimated Future Water Demands in the ACWD Service Area – Normal Year (AF/yr) ...... 28 Table 3 Estimated Future Water Demands in the ACWD Service Area – Critical Dry Year (AF/yr)...... 29 Table 4 Estimated Future Water Demands in the ACWD Service Area – Multiple Dry Years (AF/yr) ...... 30 Table 5 Water Demands for Station East Project ...... 31 Table 6 Overview of Contracts and Permits for ACWD’s Existing Water Supplies ...... 32 Table 7 Historical Water Supply Utilization by ACWD (AF/yr) ...... 33 Table 8 Summary of Potential Future Factors that may Influence ACWD Water Supply Reliability ...... 34 Table 9 State Water Project Delivery Reliability Reports (DRR) Statistics ...... 35 Table 10 Projected Normal Year Supply ...... 36 Table 11 Projected Critical Year Supply ...... 36 Table 12 Projected Multiple Dry Year Supply ...... 37 Table 13 Water Supply and Demand Comparison: Normal Year ...... 38 Table 14 Water Supply and Demand Comparison: Critical Dry Year ...... 38 Table 15 Water Supply and Demand Comparison: Multiple Dry Year ...... 38
LIST OF FIGURES
Figure 1 ACWD Service Area and Station East Project Location Map ...... 39
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SECTION 1 INTRODUCTION
BACKGROUND
The City of Union City (City) has requested a Water Supply Assessment (WSA) for the Station East Project. The Station East Project (Project) proposes redevelopment of a 24-acre site; for purposes of this WSA, the Project is defined as existing development as assumed in the 2015 Urban Water Management Plan (UWMP). The Project includes the addition of 964 residential dwelling units, 31,020 ft2 of commercial space, and approximately 376,358 ft2 of landscaped areas, including public parks, paseos, semi-private and private open space areas, as well as other landscaped areas. The Project site is approximately 24 acres located in eastern Union City, bounded by Decoto Road, 7th Street, Bradford Way, and the Union Pacific Railroad (UPRR) tracks (see Figure 1). The Project will require water supplies for the new residential and commercial uses.
The existing water provider in the area is the Alameda County Water District (ACWD or the District). The District is a retail water purveyor with a service area that includes the cities of Fremont, Newark, Union City, and parts of Hayward. The District provides water primarily to urban customers: approximately 70% of supplies are used by residential customers, with the balance (approximately 30%) utilized by commercial, industrial, and institutional customers. Net distribution system water use was approximately 41,400 acre-feet (AF), or an average of 37.0 million gallons per day (mgd) in fiscal year 2018-19. The District’s primary sources of supply come from the California State Water Project (SWP), the San Francisco Regional Water System, and local supplies from the Alameda Creek Watershed and the Niles Cone Groundwater Basin. The District’s 2015-2020 Urban Water Management Plan (UWMP or 2015 UWMP) includes estimated water demands associated with the assumed development of the Project area.
California Water Code (Water Code) Section 10910 requires that a water supply assessment be provided to cities and counties for a project that is subject to the California Environmental Quality Act (CEQA), and which surpasses a threshold for the number of housing units and/or square feet of commercial/industrial buildings. The cities and counties are mandated to identify the public water system that might provide water supply to the project and then to request a water supply assessment. The water supply assessment documents sources of water supply, quantifies water demands, evaluates drought impacts, and provides a comparison of water supply and demand that is the basis for an assessment of water supply sufficiency.
PURPOSE
The purpose of this WSA is to document the District’s existing and future water supplies for its service area and compare them to the service area’s future water demands, including the future water demands of the Project. This comparison, conducted for both normal hydrologic conditions and drought conditions, is the basis for an assessment of water supply sufficiency in accordance with the requirements of Water Code Section 10910.
4 METHODOLOGY
The District’s long-term water supply strategy was developed as part of the District’s Integrated Resources Planning Study (IRP) and adopted by the District’s Board in 1995. This strategy is incorporated into the District’s UWMP which documents the District’s existing water supplies as well as the projected future demand for water and changing availability of our supplies. The demand projections were made the year prior to completion of the UWMP, or 2015, and relied on the most current published supply reliability and land use planning data at that time. This WSA will estimate the water demand for the Project and compare it to what was included in the UWMP while using the 2015 UWMP data for analyzing and reporting water supply reliability and documenting the District’s sources of supply as required under the Water Code.
5 SECTION 2 WATER DEMAND
This section provides an overview of historical and current water use in the District as well as a summary of future projected water demands for the Project and the District’s service area.
WATER USE CATEGORIES
Water use in the District’s service area is divided into two categories: 1) distribution system use, and 2) groundwater system use.
The distribution system use includes all water uses supplied by the District’s treatment and production facilities and conveyed to the District’s customers via the District’s distribution system. This use is further subdivided into the categories of single family residential (SFR), multi-family residential (MFR), commercial, industrial, institutional, landscape, and other uses.
Groundwater system use includes private (non-ACWD) groundwater pumping (primarily for industrial and municipal landscape irrigation uses), the District’s Aquifer Reclamation Program (ARP) pumping and saline groundwater outflow to San Francisco Bay. The ARP pumping is an ongoing District program to pump brackish groundwater out of the aquifer system and replace it with fresh water recharged at the District’s groundwater recharge facilities. Saline groundwater outflow to San Francisco Bay represents the groundwater outflow required to maintain groundwater flow in a bayward direction necessary to prevent saltwater intrusion into the local aquifer system and to flush saline groundwater back to San Francisco Bay.
The District’s groundwater system use is not anticipated to change significantly in the future. Therefore, the following discussions of water use are focused on the District’s distribution system water use.
HISTORICAL AND CURRENT WATER USE
Table 1 provides a summary of the last ten years of water use within the District. As shown in the table, residential water use comprises approximately 70% of District water with the remaining 30% being used by commercial, industrial, and institutional customers.
Water consumption patterns in the District service area are a function of many independent factors including growth, weather conditions, economic conditions, and water conservation behaviors. The District saw dramatic declines in consumption during the 1987-1992 drought due to District-sponsored demand management efforts and voluntary conservation efforts by our customers. However, during the drought recovery period after 1992, several significant factors have influenced consumption. From 1993-2001 accelerated growth of both residential and business customers (including the high-tech industry) occurred due to a strong economy. During this period, vacancy rates decreased, and water consumption rose. From 2001 to 2007 the overall consumption in the District was relatively flat, attributed primarily to less robust local economic conditions, mild weather, and on-going water conservation programs. After 2007, the District saw significant declines in overall water consumption, which has been attributed to a combination of continued economic downturn, 2007-2009 successive dry year conditions, and
6 statewide conservation campaigns. Since the previous UWMP (2010-2015 UWMP), the State of California has experienced a drought, and the resulting substantial reduction in demand for water has changed the District’s near- and mid-term anticipated levels of new demands from those reported in the previous UWMP.
The drought ended in 2017, and demand has begun to rebound. Water use in 2019 was consistently higher than during the drought period, but demand has not rebounded to pre-drought levels. In addition, development activity has risen throughout the District’s service area due to a strong economy.
WATER DEMANDS - ACWD SERVICE AREA
The District’s approach to water demand forecasting is to: 1) analyze existing demands associated with current land usage; 2) coordinate with City planning staff to obtain future land use plans; 3) estimate potential demands of currently undeveloped lands that are zoned for development; 4) estimate future demands resulting from approved land use changes for already developed lands; and 5) estimate anticipated demand reductions from on-going water conservation and plumbing code changes. This approach is proven sufficiently accurate for long- term, District-wide demand forecasting and is consistent with the California Water Code requirements for urban water management planning. Demand forecasting is done for six primary land use categories: single family residential, multi-family residential, commercial, industrial, institutional, and “other.” Existing customer water use in each of these categories is analyzed using multiple linear regression modeling techniques of stochastic variables that affect water demands including weather, plumbing codes, economic and public policy factors. This analysis generates "unit demand" figures for each of the land use categories. The District then coordinates with planning staff from the Cities of Fremont, Newark, and Union City to compile future land use assumptions for both undeveloped and developed land that has been designated for changed use. This includes current City plans (general and specific) as well as forecast development included in the Association of Bay Area Governments (ABAG) most recent regional projections which provide target housing units and employment numbers for the Tri-City area and that Cities have agreed to meet. ABAG was consolidated with the Metropolitan Transportation Commission on July 1, 2017, and now make up the government organization known as the Bay Area Metro. The 2015 Forecast relies more on ABAG projections than previous forecasts due to the near build out of the service area and changing trends in land use and development. A District-wide demand forecast for each land use category, as well as the total District-wide demand, is then developed by multiplying the planned land use under each land use category by the unit demand factors.
Actual unit water use for any specific land use project may vary significantly from the District- wide average. However, determining the actual unit water use for each specific development project in the service area is beyond the scope of the District’s UWMP demand forecast. Rather than providing demand forecasts for specific land use projects, the UWMP provides an aggregated, District-wide demand forecast for each land use category, as well as the total District-wide demand. This approach is proven sufficiently accurate for long-term, District-wide demand forecasting and is consistent with the California Water Code requirements for urban water management planning. However, if the District has detailed information about the water
7 demands of a specific project during the time it is preparing the UWMP, the District will account for the specific project's water demands in the UWMP in lieu of the District-wide average.
The projected future demands in the District service area are summarized in Table 2 (for the years 2020, 2025, 2030, 2035, and 2040). The water demand forecast also includes projected savings from water conservation - both “active conservation” sponsored by the District and “passive conservation” which results from improved plumbing code standards. The District is committed to the implementation of all locally cost-effective water conservation best management practices. A complete description of the District’s water conservation program, as well as water saving assumptions, is provided in Chapter 7 of the attached UWMP. The District is also preparing to achieve water efficiency standards that will be determined through implementation of the statewide water use efficiency framework “Making Conservation a California Way of Life.” The District anticipates reduced future demands for water compared to previous forecasts as well as in comparison to demonstrated past levels of actual demand. These reductions in total demand come despite a net increase in total housing per City and ABAG projections. The District also anticipates a continued decrease in per-capita water demands due to pronounced conservation effects as well as an increased ratio of high-density to low-density housing (discussed further in Chapter 8 of the attached UWMP). These trends also reflect the continued transition of the local industrial sector from water intensive manufacturing to lower water demand activities.
As described in the following section, the Project’s demands are considered to be consistent with the District’s demand forecast, and therefore, are not listed separately in Table 2. The current demand forecast takes into account all WSAs completed prior to the publication of the 2015- 2020 UWMP as well as all WSAs completed since the publication of the 2015-2020 UWMP.
WATER DEMANDS – STATION EAST PROJECT
Estimation of Project Water Demands
The Station East Project proposes to add new development and to redevelop portions of the existing Decoto Industrial Park. The Project site is approximately 24 acres located in eastern Union City, bounded by Decoto Road, 7th Street, Bradford Way, and the Union Pacific Railroad (UPRR) tracks (see Figure 1). The Project site is currently developed as part of the Decoto Industrial Park. The Project includes the addition of 964 residential dwelling units, 31,020 ft2 of commercial space, and approximately 376,358 ft2 of landscaped areas, including public parks, paseos, semi-private and private open space areas, as well as other landscaped areas. None of the existing industrial development will remain as this project will redevelop the entire site.
Information on the Project’s proposed land use was provided by the City of Union City and is listed in Table 6. City of Union City Staff has indicated that the data represents the upper end of development potential. ACWD estimates the Project will result in approximately 103 AF/yr of new demand. ACWD’s most recent demand forecast included demand for the proposed residential development, while the additional commercial building area is consistent with existing land-use zoning contemplated in the forecast. Therefore, the Project is included in ACWD’s most recent forecast and water supply planning analyses in the 2015-2020 UWMP.
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Water Efficiency Measures to be Incorporated in the Project
In order to ensure that the Project incorporates the most up-to-date water efficiency measures, the Project should be developed with water efficient plumbing fixtures and irrigation systems at non-residential developments, including but not limited to those listed in Attachment D – Water Efficiency Measures for New Developments.
IMPACTS OF DROUGHT ON DEMANDS
Historically, dry periods have impacted water demands in several ways. Because approximately 35% of the District’s demand comes from landscape irrigation, dry periods tend to increase demands as low rainfall and higher temperatures result in increased evapotranspiration requirements for landscaping. However, when dry periods extend in length or intensity and become designated as drought, public awareness campaigns at local, regional, and state level have typically reduced demands due to customer awareness and social consciousness. District customers have a proven history of high awareness of drought and responsible water usage during dry periods. In extreme dry periods, the District may set either a voluntary or even mandatory water use reduction targets (as discussed in Chapter 10 of the UWMP). These restrictions have historically resulted in large, temporary demand reductions as customers curtail non-essential water use and implement lasting conservation measures. After past drought periods, the temporary reductions have returned gradually to pre-drought levels, taking upwards of five years. However, as demonstrated during past droughts, District customers, like California residents on whole, have also implemented permanent demand reductions during the drought which extend beyond the end of the drought and have lasting effects of reduced demands for water. These demand reductions occur as a result of accelerated implementation of water efficiency and conservation measures during the drought due to heightened customer awareness.
As an example, during the 1987-1992 drought, District customers reduced overall water use by approximately 20% as the result of both voluntary efforts and mandatory restrictions imposed by the District with a lasting 5% reduction after the drought ended. During the most recent drought, District customers reduced overall water use, through April 2016, by nearly 28% relative to baseline demands in 2013. The District has had an unprecedented participation in conservation programs during the most recent drought and estimates that a permanent 6% demand reduction will last beyond the end of drought. Because of the continued implementation of natural and programmatic conservation, the ability to reduce overall volumetric water use during future droughts by similar levels may be lessened. For planning purposes, the 2015 Forecast assumed the then current drought to end in 2016, with demand rebound to occur over the next five years from 2017-2021. On April 7, 2017, Governor Brown declared an end to the most recent drought.
For planning purposes, it is conservatively assumed that, during drought periods, water demands for the District’s distribution system customers do not change from those during normal years. However, dry years result in lower groundwater levels, caused by reduced local recharge and increased reliance on groundwater storage, which results in reduced saline groundwater outflows. In addition, the District will often minimize ARP pumping in order to reduce groundwater system demands during dry periods. Summaries of projected demands including
9 the Project demands under single dry year and multiple dry year conditions (based on a five-year drought under 2036-2040 demand conditions) are provided in Table 3 and Table 4 respectively.
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SECTION 3 WATER SUPPLY
The District’s three primary sources of water supply are: 1) the State Water Project (SWP); 2) San Francisco’s Regional Water System; and 3) local supplies. The SWP and San Francisco Regional Water Supplies are imported into the District service area through the South Bay Aqueduct and the Hetch-Hetchy Aqueduct, respectively. Local supplies include fresh groundwater from the Niles Cone Groundwater Basin, desalinated brackish groundwater from portions of the groundwater basin previously impacted by seawater intrusion, and surface water from the Del Valle Reservoir. The primary source of recharge for the Niles Cone Groundwater Basin is percolation of runoff from the Alameda Creek watershed. To a lesser degree, a portion of ACWD’s SWP supplies are also used for local groundwater percolation. Infiltration of rainfall and applied water within the District service area also contribute to local groundwater recharge.
Due to the configuration of the District’s water production facilities and the interconnection with the District’s distribution system, the proposed Project may receive water supplies from all three primary sources of supplies and would not be dependent on any single source of supply. Therefore, a description of ACWD’s water supplies is provided below. Table 6 provides a summary description of the contracts and permits for these supplies, and Table 7 provides a summary of the historical use of these supplies by ACWD.
WHOLESALE WATER SUPPLIES
As described above, ACWD’s wholesale water supplies are: 1) State Water Project supplies purchased from the California Department of Water Resources; and 2) San Francisco Regional Water System supplies purchased from San Francisco. ACWD’s contracts for these wholesale supplies are provided in Attachment C, and each supply is described in greater detail below.
State Water Project
In 1961, the District signed a contract with the State Department of Water Resources (DWR) for a maximum annual amount of 42,000 acre-feet from the SWP, referred to as ACWD’s “maximum Table A allocation.” The SWP, managed by the DWR, is the largest state-built, multi-purpose water project in the country. The SWP facilities include 28 dams and reservoirs, 26 pumping and generating plants, and approximately 660 miles of aqueducts. The water stored in the SWP storage facilities originates from rainfall and snowmelt runoff in Northern and Central California watersheds. The SWP’s primary storage facility is Lake Oroville in the Feather River Watershed. Releases from Lake Oroville flow down the Feather River to the Sacramento River, which subsequently flows to the Sacramento-San Joaquin Delta. The SWP diverts water from the Delta through the Banks Pumping Plant which lifts water from the Clifton Court Forebay (in the Delta) to the California Aqueduct and Bethany Reservoir. From Bethany Reservoir, the South Bay Pumping Plant lifts water into the South Bay Aqueduct, which delivers State Water Project supplies to ACWD and other Bay Area water agencies in Alameda and Santa Clara Counties.
11 Semitropic Banking of ACWD’s SWP Supplies: Because of the variability in the SWP supply availability, ACWD’s 1995 IRP identified the need to secure 140,000 AF of off-site storage capacity to improve the dry year reliability of this supply source. Based on this IRP recommendation, ACWD has contracted with Semitropic Water Storage District for participation in the Semitropic Groundwater Banking Program in Kern County. In wet years, ACWD delivers its unused (excess) SWP supplies to Semitropic for storage in their groundwater basin. In dry years, ACWD can recover these supplies through: (1) an “in-lieu” exchange whereby ACWD will receive a portion of Semitropic’s SWP supplies (and Semitropic will utilize groundwater previously stored by ACWD in its basin); and (2) a “pumpback” program where Semitropic directly pumps stored groundwater into the California Aqueduct and ACWD recovers this supply through SWP exchanges.
The rate at which ACWD can recover stored water in dry years is constrained by contractual limitations and limitations on the capacity of the Semitropic pumpback facilities. Based on the terms of the agreements with Semitropic, the amount of return capacity is based on the amount of storage capacity purchased. Because of these limitations, ACWD secured a total of 150,000 AF of storage capacity at Semitropic (in excess of the IRP’s recommendation of 140,000 AF), in order to provide sufficient dry year return capacity to meet ACWD’s projected needs in all but the most severe drought conditions.
The Semitropic Groundwater Banking Program does not provide a new source of supply for the District. Rather, it provides a means to store the District’s unused SWP supplies in wet years for use during dry years when the delivery of SWP supplies may be significantly curtailed.
San Francisco’s Regional Water System
ACWD also receives water from the San Francisco Regional Water System, operated by the San Francisco Public Utilities Commission (SFPUC). This supply is predominantly from the Sierra Nevada, delivered through the Hetch-Hetchy aqueducts, but also includes treated water produced by the SFPUC from its local watersheds and facilities in Alameda and San Mateo Counties. The amount of imported water available to the SFPUC’s retail and wholesale customers is constrained by hydrology, physical facilities, and the institutional parameters that allocate the water supply of the Tuolumne River.
In 2009, ACWD, along with the other wholesale customers, signed a new Master Sales Agreement with San Francisco, supplemented by an individual Water Sales Contract. The new agreements have a term of 25 years and provide a commitment from San Francisco to provide, collectively, up to 184 mgd to its wholesale customers. ACWD’s individual supply assurance is 13.76 mgd. In 2019, the Agreement was amended to address administrative issues; these amendments have no impact on ACWD’s reliability assumptions as reported in the 2015-2020 UWMP.
12 LOCAL SOURCES
As described above, ACWD’s local sources include fresh groundwater from the Niles Cone Groundwater Basin, brackish groundwater desalination, and surface water supplies from the Del Valle Reservoir. Each of these supplies is described in greater detail below.
Niles Cone Groundwater Basin
The principal source of local supply for the District is the local aquifer system known as the Niles Cone Groundwater Basin. The primary source of recharge for the Niles Cone Groundwater Basin is local runoff from the Alameda Creek Watershed, which is captured, diverted and recharged at the District’s groundwater recharge facilities. To a lesser extent, infiltration of rainfall and applied water within the ACWD service area also provide a local source of recharge for the groundwater basin. Though not a local supply but mentioned here for completeness, ACWD also uses a portion of its imported State Water Project supplies for groundwater recharge to more effectively manage the groundwater basin.
Chapter 3 of the 2015 UWMP documents the range in availability of supply from Alameda Creek and includes environmental bypass flow requirements from a March 2011 agreement between ACWD and the National Marine Fisheries Services (NMFS) and the California Department of Fish and Wildlife (CDFW).
The water quality in the groundwater system is characterized by fresh groundwater in the eastern portion of the groundwater basin transitioning into brackish groundwater in the western portion of the basin. The brackish groundwater is a result of historical seawater intrusion from the adjacent San Francisco Bay. Since the 1960’s ACWD has managed the groundwater basin to prevent any additional seawater intrusion and has an on-going program to pump trapped brackish groundwater back to San Francisco Bay through the District’s Aquifer Reclamation Program wells.
The Niles Cone Groundwater Basin has capacity to store water from year to year (“local groundwater storage”). However, the usable storage capacity of the groundwater basin is significantly limited by the potential for saltwater intrusion if groundwater levels are maintained too low. Although local groundwater storage (i.e. groundwater supplies in excess of recharge) provides a short term source of supply during dry years, it is not a supply that is available every year because the groundwater system will require replenishment from freshwater sources, without which saltwater intrusion would occur.
Chapter 4 of the UWMP (attached) provides a comprehensive description of the Niles Cone Groundwater Basin, including groundwater quality, groundwater levels, historical and projected groundwater pumping, and ACWD’s groundwater management activities. A copy of ACWD’s groundwater management policy is also provided in the UWMP. Information regarding the Niles Cone Groundwater Basin can also be found in a number of DWR Bulletins, including the most recent DWR Bulletin 118 – Interim Update 2016 California’s Groundwater, Working Toward Sustainability.
13 On September 16, 2014, Governor Jerry Brown signed a three-bill package known as the Sustainable Groundwater Management Act (SGMA) into law that establishes a new structure for groundwater management, recognizing that groundwater management in California is best accomplished locally. The Niles Cone Groundwater Basin is identified by DWR as a medium priority basin and is not identified by the DWR as being subject to critical conditions of overdraft. SGMA identifies ACWD as one of 15 agencies that were created by statute to manage groundwater and deemed the exclusive local agency to comply with SGMA. On November 10, 2016, ACWD’s Board of Directors adopted Resolution No. 16-069 deciding to become the Groundwater Sustainability Agency (GSA) for the Niles Cone Subbasin 2-09.01 and on December 8, 2016, ACWD’s Board of Directors adopted Resolution No. 16-075 authorizing the submittal of an Alternative to a Groundwater Sustainability Plan for the Niles Cone Subbasin 2- 09.01 (Alternative). The California Department of Water Resources (DWR) reviewed ACWD’s Alternative, and in a letter dated July 17, 2019, concluded that the Alternative satisfies the objectives of SGMA and was approved. The approval of ACWD’s Alternative together with pre- existing authority by which ACWD has carried out groundwater management efforts will allow ACWD to continue the successful management of the Niles Cone Groundwater Basin.
Brackish Groundwater Desalination
In 2003 ACWD commissioned the Newark Desalination Facility which utilizes the reverse osmosis process to remove salts and other impurities from the brackish groundwater pumped at ACWD’s Aquifer Reclamation Program wells. Treated water from the Newark Desalination Facility is blended with untreated local groundwater and provided as a supply for the distribution system demands. In 2010, ACWD expanded this facility to 10-mgd.
Del Valle Reservoir
The District and Zone 7 Water Agency of the Alameda County Flood Control and Water Conservation District (Zone 7), have equal rights on Arroyo Del Valle to divert water to storage. When the California Department of Water Resources (DWR) constructed Del Valle Dam in the upper Alameda Creek Watershed, those rights were recognized in an agreement among DWR, the District, and Zone 7. Consequently, DWR typically makes a total of 15,000 AF of storage available annually in Del Valle Reservoir for use by ACWD and Zone 7. ACWD and Zone 7 equally share this storage capacity, thereby providing up to 7,500 AF of storage capacity to ACWD.
Recycled Water
The District’s long-term supply strategy includes a potential recycled water program to provide upwards of 2,600 AF/yr of non-potable supply. Non-potable supply can only be used to meet limited forms of demand for non-potable water, such as landscape irrigation and industrial process water. As described in Chapter 6 of the UWMP, the source of recycled water will likely be from a joint project with ACWD and Union Sanitary District (USD) though it could be sourced from another location such as the South Bay Water Recycling Program. Recycled water distribution pipelines are separate from the District’s existing potable distribution system and, therefore, would not adversely affect existing potable supply operations. The volume of recycled water produced would be the same in drought years as in normal years, thus providing a firm
14 source of supply. Demand for recycled water for irrigation purposes is highest in the summer months. Therefore, in addition to increasing water supply, use of reclaimed water would help meet peak monthly and daily production capacity needs.
ACWD and USD have continuously reevaluated the feasibility of implementing a recycled water program with studies conducted in 1993, 2000, 2003, 2010, and 2015. These studies document a continuous decline in the potential demand for a non-potable water supply over the years due to a reduction in water-intensive manufacturing, elimination of two previously planned future golf- courses, and a suite of State imposed regulations that in combination reduce the future demand for irrigation. With large implementation costs and a declining yield, the cost effectiveness of a non-potable recycled water project becomes increasingly unrealistic. As a result, the ACWD and USD Recycled Water Feasibility Study 2015/16 was expanded to include an evaluation of indirect potable reuse (IPR). Advances in treatment technology and the successful, multi-decade operation of several IPR projects in California have led to new streamlined regulations allowing for the safe reuse of wastewater to supplement raw water supplies used to meet potable demands. An IPR project would use Advanced Treatment to purify wastewater to drinking water standards. However, as an added safety factor this purified water would be used to help recharge the Niles Cone Groundwater Basin where it would undergo additional natural filtering and dilution with other raw water sources before being produced as a potable supply at one of ACWD’s groundwater production facilities. The 2015 study found that over 4,000 AF of additional recharge supply could be provided by an IPR project and at a lower cost than a non-potable project. ACWD is presently conducting a next-level feasibility study of IPR potential with USD and the SFPUC
Recycled water is not included in the 25-year planning horizon of the water supply-demand comparisons provided in the 2015 UWMP; however, it is considered a potential future source of supply for ACWD, especially in light of uncertainties with the reliability of existing supplies, and is included in ACWD’s Capital Improvement Program. As part of the District’s next review of the Integrated Resources Planning Study, ACWD will continue to evaluate the potential timing for a future recycled water project in the service area.
WATER SUPPLY UNCERTAINTIES
The purpose of this section is to identify factors which may impact current planning assumptions, the significance and magnitude of which are currently unknown. As described below, the potential impacts of global warming are a key uncertainty which may impact all of ACWD supplies. In addition, each of ACWD’s supplies face uncertainties which may be unique to the source of supply. A summary of water supply uncertainties facing ACWD’s supplies is provided in Table 8 and discussed in greater detail below.
Climate Change
The issue of climate change has become an important factor in water resources planning in California and is frequently considered in urban water management planning purposes, though the extent and precise effects of climate change remain uncertain. There is convincing evidence that increasing concentrations of greenhouse gasses have caused and will continue to cause a rise in temperatures around the world, which will result in a wide range of changes in climate
15 patterns. Moreover, observational data show that a warming trend occurred during the latter part of the 20th century and virtually all projections indicate this will continue through the 21st century. These changes will have a direct effect on water resources in California, and numerous studies have been conducted to determine the potential impacts to water resources. Based on these studies, climate change could result in the following types of water resource impacts, including impacts on the watersheds in the Bay Area: • Reductions in the average annual snowpack due to a rise in the snowline and a shallower snowpack in the low and medium elevation zones, and a shift in snowmelt runoff to earlier in the year; • Changes in the timing, intensity and variability of precipitation, and an increased amount of precipitation falling as rain instead of as snow; • Long-term changes in watershed vegetation and increased incidence of wildfires that could affect water quality and quantity; • Sea-level rise and an increase in the potential for saltwater intrusion in the Delta and Coastal aquifers such as the Niles Cone; • Increased water temperatures with accompanying potential adverse effects on some fisheries and water quality; • Increases in evaporation and transpiration (irrigation need); and • Changes in urban and agricultural water demand.
Each of the District’s supply sources will be affected uniquely by climate change and are discussed below.
State Water Project: In addition to changed weather patterns, the SWP is anticipated to have operational challenges in the Delta stemming from climate change as well. DWR notes:
“climate change poses the threat of increased variability in floods and droughts, and sea level rise complicates efforts to manage salinity levels and preserve water quality in the Delta so that the water remains suitable for urban and agricultural uses. Among the other challenges are continued subsidence of Delta islands, many of which are already below sea level, and the related threat of a catastrophic levee failure as water pressure increases on fragile levees.” (DWR, State Water Project Delivery Capability Report 2015)
DWR coordinates with the Climate Action Team (CAT) in order to capture changing weather patterns and the impacts of sea-level rise in the State Water Project Delivery Capability Report (DCR), previously known as the Delivery Reliability Reports (DRR). The CAT reports that SWP reliability will be further diminished in the future with impacts beginning to become significant in the latter half of the 21st century. However, the water supply impacts anticipated from climate change are minimal during the 20-year purview of the UWMP; these impacts include climate impacts from the 2025 Green House Gas (GHG) emission assumptions and 15-cm of assumed sea-level rise.
San Francisco Regional Water System: Climate change research by the SFPUC began in 2009 and continues to be refined. In its 2012 report “Sensitivity of Upper Tuolumne River Flow to Climate Change Scenarios,” the SFPUC assessed the sensitivity of runoff into Hetch Hetchy
16 Reservoir to a range of changes in temperature and precipitation due to climate change. Key conclusions from the report include the following: • With differing increases in temperature alone, the median annual runoff at Hetch Hetchy would decrease by 0.7-2.1 percent from present-day conditions by 2040 and by 2.6-10.2 percent from present-day by 2100. Adding differing decreases in precipitation on top of temperature increases, the median annual runoff at Hetch Hetchy would decrease by 7.6- 8.6 percent from present-day conditions by 2040 and by 24.7-29.4 percent from present- day conditions by 2100. • In critically dry years, these reductions in annual runoff at Hetch Hetchy would be significantly greater, with runoff decreasing up to 46.5 percent from present day conditions by 2100 utilizing the same climate change scenarios. • In addition to the total change in runoff, there will be a shift in the annual distribution of runoff. Winter and early spring runoff would increase, and late spring and summer runoff would decrease. • Under all scenarios, snow accumulation would be reduced, and snow would melt earlier in the spring, with significant reductions in maximum peak snow water equivalent under most scenarios.
Currently, the SFPUC is planning to conduct a comprehensive assessment of the potential effects of climate change on water supply. The assessment will incorporate an investigation of new research on the most recent drought; this information will be available prior to and included in ACWD’s next UWMP updated in 2020.
Both the District and SFPUC participated in the 2013 update of the Bay Area Integrated Regional Water Management Plan (BAIRWMP), which includes an assessment of the potential climate change vulnerabilities of the region’s water resources and identifies climate change adaptation strategies. These works are summarized in Appendix B.
Local Groundwater: In 2003, and then again in an update prepared in August 2005, the Pacific Institute for Studies in Development, Environment and Security prepared a literature search report for DWR, which summarized recommendations for coping with and adapting to climate change from key peer-reviewed publications and specifically considered the potential impacts of climate change on groundwater. The Pacific Institute’s report is entitled, Climate Change and California Water Resources: A Survey and Summary of the Literature, by Michael Diparsky and Peter H. Gleick, Pacific Institute (Climate Change and Water Resources).
Climate Change and Water Resources found that little work has been done on the impacts of climate change for specific groundwater basins, or for general groundwater recharge characteristics or water quality. As the following conclusions from the report illustrate, the potential impacts of climate change on groundwater resources are divided, with some potentially resulting in increased availability of groundwater and others potentially resulting in less. • Changes in recharge will result from change in effective rainfall as well as a change in the timing of the recharge season. Increased winter rainfall could lead to increased groundwater recharge. • Higher evaporation or shorter rainfall seasons could mean that soil deficits persist for longer periods of time, shortening recharge seasons.
17 • Because a significant portion of winter recharge comes from deep percolation of precipitation below the rooting zone, warmer winter temperatures between storms would be expected to increase and dry out the soil between storms. A greater amount of rain in subsequent storms would then be required to wet the root zone and provide water for deep percolation. • Sea-level rise could affect coastal aquifers through saltwater intrusion. • Warmer, wetter winters would increase the amount of runoff available for groundwater recharge. However, this additional runoff would be occurring at a time when some basins are either being recharged at their maximum capacity or are already full. • Reductions in spring runoff and higher evapotranspiration because of higher temperatures could reduce the amount of water available for recharge. • In 2009, the District performed a preliminary modeling study to evaluate future impacts on groundwater levels and legacy saltwater intrusion in the Niles Cone in response to hypothetical increases in sea level. The District has shared the results with the Coastal Hazards Adaptation Resiliency Group (CHARG).
Bay Delta Water Quality Control Plan Update
On December 12, 2018, the State Water Resources Control Board (State Water Board) adopted Phase I amendments to the San Francisco Bay/Sacramento-San Joaquin Delta Estuary Water Quality Control Plan (Bay-Delta Plan) and adopted the Final Substitute Environmental Document (SED) related to those Phase I amendments. The amendments include flow requirements for the Lower San Joaquin River and its tributaries, including the Tuolumne River, to maintain 40% unimpaired flow, within an adaptive range between 30-50% unimpaired flow, from February through June. The flow requirements, if implemented, would have potentially significant impacts to District imported water supplies from SFPUC.
Currently, negotiations are underway between the California Department of Fish and Wildlife Services, the California Department of Water Resources, and watershed stakeholders to develop Voluntary Settlement Agreements (VSAs) that may be considered in the analysis of alternatives to be considered during the Bay-Delta Plan Phase II environmental review. Phase II amendments to the Bay-Delta Plan will build on Phase I updates and address flow requirements to the Sacramento River and its tributaries. The flow requirements, under consideration in Phase II may have potentially significant impacts to District imported water supplies from the State Water Project. The VSAs under consideration include both flow and non-flow measures, such as fallowing, habitat improvements, predator control, and exclusion barriers.
The State Water Board would implement the Bay-Delta Plan in a future Phase III, to occur after completion of Phase II. Given the uncertainty in how any potential State Water Board decisions during Bay-Delta Plan Phase II could affect the State Water Board’s actions in Phase I, it is too early to evaluate the likely water supply impacts of the Phase I decision.
Local Supplies
In addition to potential climate change impacts, the availability of ACWD’s local supplies may be influenced by a variety of other factors including additional operational and facility modifications to accommodate on-going Alameda Creek fishery restoration efforts beyond those
18 agreed to by NMFS/CDFW. Upstream land use, flood control and water supply projects in the Alameda Creek Watershed may also impact the supply and quality of water available at ACWD’s groundwater recharge facilities. There also may be uncertainties regarding future releases from the major reservoirs in the Alameda Creek Watershed, including Calaveras and San Antonio Reservoirs (SFPUC) and Del Valle Reservoir (DWR), as required for environmental purposes and/or operational agreements. This includes, for example, an arrangement between ACWD and SFPUC that provided water to ACWD for groundwater recharge during a period when the Niles Cone Groundwater Basin was in overdraft condition and threatened by seawater intrusion. Similarly, efforts to develop groundwater supplies by entities in the South East Bay Plain (north of ACWD) may also impact ACWD’s groundwater supply availability. ACWD is currently working to address these items. However, it is unclear whether these issues will ultimately impact ACWD’s local supplies.
San Francisco Regional Supplies
In order to enhance the ability of the SFPUC water supply system to meet identified service goals for water quality, seismic reliability, delivery reliability, and water supply, the SFPUC is undertaking a Water System Improvement Program (WSIP). Completion of the projects in the WSIP is critical for the SFPUC in order to achieve the stated reliability goals for the San Francisco Regional Supplies. However, it is currently uncertain if the SFPUC will be successful in fully implementing this program, and if it will be accomplished in a timely manner. Other factors that may impact the reliability of RWS supplies include environmental regulations and permitting requirements for its Hetch-Hetchy and local watershed facilities and operations. Additional information on potential factors affecting the San Francisco Regional Supplies reliability is provided in Appendix B of the 2015 UWMP.
As discussed above, the State Water Resources Control Board has proposed substantial changes to flow objectives for the Tuolumne River. These changes are anticipated to result in reduced surface water available for diversions, thereby potentially causing significant impacts to water supply from the San Francisco Regional System.
State Water Project Supplies
The reliability of the District’s SWP supplies will continue to remain uncertain due to the on- going concerns regarding the sustainability of the Delta. These concerns include the Delta ecosystem and potential future environmental regulations, levee stability and the potential for catastrophic failure of these levees, urban encroachment within the Delta, and water quality within the Delta due to urban and agricultural discharges.
The Delta Conveyance Project has been proposed to address the Delta’s issues of aging infrastructure, to improve seismic resiliency, and prepare for anticipated challenges of climate change. Under current operations, water is exported from the Sacramento-San Joaquin Delta to the State Water Project (SWP) and the Central Valley Project (CVP) after it flows through a maze of river channels and sloughs toward intake stations for the California Aqueduct and the Delta-Mendota Canal located in the South Delta. This braided channel flow through the Delta disrupts natural river flow direction away from the San Francisco Bay which in turn disrupts aquatic species’ lifecycles. The Delta Conveyance Project proposes to build a
19 seismically resilient tunnel to carry fresh water from the Sacramento River below the Sacramento-San Joaquin Delta toward the intake stations, reducing the disruptive effects on in- Delta river flows. The Delta Conveyance Project would allow for greater flexibility in balancing the needs of the estuary with the reliability of water supplies. The Project would also provide other benefits, such as reducing the risk of long outages from Delta levee failures.
The Delta Conveyance project is a large and complex endeavor with ongoing challenges including legal and financing issues which must be resolved prior to any construction. Because of this uncertainty, any improvements in SWP supply reliability or other benefits that could result from this proposed project are not included in this WSA.
Delta Disruption due to low water supply availability. On January 31, 2014, DWR announced a 0% Table A allocation for the first time in its 54-year history. Although the allocation was subsequently raised to 5%, this water was not available before September 1, 2014, after the typical summer high demand season. Being situated downstream of the Delta but upstream of the major water storage facilities of the SWP, the District was in a uniquely vulnerable position. Among other factors, this disruption of the SWP created an uncertainty surrounding the District’s ability to access remotely stored supplies in Semitropic Groundwater Bank and San Luis Reservoir leading the District to declare a Water Shortage Emergency targeting 20% conservation District-wide, following plans outlined in the Chapter 10 of the UWMP (Water Shortage Contingency Plan).
Despite this low allocation, DWR’s DCR modeling scenarios still considers the minimum reliability to be between 8% and 11% in the various scenarios as documented in Table 3-2. The 2014 condition has been described as the result of a rare sequence of extreme hydrology in water year 2013.1 October through December 2012 was one of the wettest fall periods on record, but was followed by the driest consecutive 12 months on record. The 2013 hydrology ended up being even drier than DWR’s conservative hydrologic forecast, resulting in initial reservoir storage levels for 2014 that were lower than targeted levels with less stored water available for 2014 supplies. Compounding this low initial storage situation, 2014 also was an extremely dry year, with runoff for water year 2014 being the fourth driest on record. Due to the extraordinarily dry conditions in 2013 and 2014, the 2014 Table A allocation was a historic low, only 5%. The unusual hydrologic conditions are not included in the DCR which only runs through year 2003.2 It is anticipated that the hydrologic record used in the DWR model will be extended to include the period through 2014 during the next update of the model, which is expected to be completed in the coming year.
As discussed above, the State Water Resources Control Board has proposed substantial changes to flow objectives for the Sacramento River and related tributaries. These changes are anticipated to result in reduced surface water available for diversions, thereby potentially causing significant impacts to water supply from the SWP.
1 A water year begins in October and runs through September. For example, water year 2013 is October 2012 through September 2013. 2 SWP delivery estimates from DWR’s 2015 SWP Delivery Capability Report are from computer model studies which use 82 years of historical hydrologic inflows from 1922 through 2003.
20 Semitropic Banking Program
The District faces some uncertainty with regards to recovery of water from the Semitropic Banking Program. These uncertainties include: 1) water quality concerns with regard to groundwater from Semitropic that is pumped back into the California Aqueduct; 2) the availability of exchange and/or delivery capacity to deliver water to or recover water from Semitropic; and 3) repercussions of the recent Sustainable Groundwater Management Act (SGMA) on the operations of the Banking Program. With regards to the water quality issues, in 2013 Semitropic initiated a Raw Water Processing Facility (RWPF) to capture raw water constituents of concern before the groundwater is pumped into the California Aqueduct. Since initiation in 2013, Semitropic was able to meet or exceed DWR’s water quality pump-in criteria, therefore reliability concerns associated with Water Quality have been greatly reduced. It is possible that in the future, additional constituents of concern could be identified, and Semitropic may be required to expand or revise its RWPF. With regards to the exchange and delivery capacities needed to both deliver water to and recover dry year supplies from Semitropic, the District has coordinated with Semitropic, DWR, and other Semitropic Banking partners to ensure coordination of the planned use of the Semitropic delivery and recovery capacity and the needed exchanges. During the recent drought in 2014, Semitropic demonstrated the ability to return the District’s banked supplies even during the temporary 0% Table A allocation. However, the risk remains that, under certain critical dry year conditions, the District may be limited in its ability to recover its contractual recovery capacity from Semitropic. Potential mitigation measures to minimize the risk associated with the constraints in Semitropic dry year recovery may include: 1) re-operation of local and other storage available to the District (i.e. Niles Cone Groundwater Basin, Del Valle Reservoir, San Luis Reservoir) in coordination with recovery from Semitropic; 2) non-project water storage options such as Los Vaqueros Reservoir; and 3) alternative dry year supply programs.
SB 7 – Water Conservation Requirements under the 2009 Comprehensive Water Package
The Water Conservation Bill of 2009 (SBX7-7), requires a statewide 20% reduction in urban per capita water use by 2020. It requires urban water retail suppliers such as ACWD to determine baseline water use and set reduction targets according to specified requirements to be achieved by 2020. See Chapter 8 of the 2015 UWMP for additional information on ACWD’s baseline and targets.
As documented in the 2015 UWMP, based on current actual consumption and forecast demand for water, ACWD is currently meeting the 2020 compliance target and is projected to continue to comply with SBX7-7 in year 2020 and beyond.
21 AB 1668 and SB 606 – Making Water Conservation a California Way of Life
Assembly Bill 1668 and Senate Bill 606 were signed into law on May 31, 2018, and require the State Water Resources Control Board, in coordination with the Department of Water Resources, to adopt long-term standards for the efficient use of water as part of carrying out then Governor Brown’s Executive Order B-37-16 “Making Water Conservation a California Way of Life.” Each urban retail water supplier, including the District, are required to set new permanent water use targets for their service areas as a whole, not on a per customer basis.
While there are no immediate impacts to customers, efficiency standards will be set for indoor and outdoor water use and water loss and included in the 2020-2025 UMWP; there are no changes to the 2015 UWMP regarding this legislation. The District will continue to recommend water saving practices and promote Water Efficiency Measures for New Residential Development as described in Attachment D.
WATER SUPPLY IN NORMAL AND DRY YEAR CONDITIONS
The projected availability for each of ACWD’s water supplies under normal, critical dry year, and multiple dry year conditions are provided in Table 10 through Table 12. As documented in the District’s 2015 UWMP, information on the projected availability of ACWD’s local supplies is based on the long-term historical hydrologic conditions in the Alameda Creek Watershed. Information on the projected reliability of ACWD’s wholesale supplies from the State Water Project and San Francisco Regional Water System supplies were provided by the DWR and San Francisco Public Utilities Commission, respectively.
Water Supply under Normal Year Conditions
In order to be consistent with the recommendations by the DWR in the use of SWP reliability information, this water supply assessment characterizes long-term average conditions as normal year conditions. As shown in Table 10, under normal year conditions supplies from the SWP and San Francisco Regional Water System comprise approximately 56% of the water available to ACWD, with the balance coming from local supplies. All of the supplies listed in Table 10 are existing supplies available to ACWD, and have been historically utilized by the District. Supplies from local groundwater reserves and the Semitropic Groundwater Banking Program are not included as normal year supplies because these supplies are intended for dry year conditions (or other water shortages) and are not intended to meet normal year demands.
22 Water Supply under Critical Dry Year Conditions
As shown in Table 11, the availability of ACWD’s overall water supplies under a critically dry year may be significantly reduced. Under critically dry conditions, the SWP deliveries would be reduced to approximately 8% of the maximum contractual amounts (referred to as the “Table A” amounts in the SWP contracts). In addition, ACWD’s other supplies from the San Francisco Regional Water System and local supplies from the Alameda Creek Watershed may also be substantially reduced during a critically dry year.
In order to mitigate these potentially severe water supply cut-backs, ACWD would rely on groundwater reserves stored in the local Niles Cone Groundwater Basin, and reserves stored at the Semitropic Groundwater Banking Program. As described above, the amount of storage in the local Niles Cone Groundwater Basin is limited due to threats of seawater intrusion when groundwater elevations fall below sea-level. ACWD has therefore invested in additional off-site storage at the Semitropic Groundwater Banking Program. Under two separate agreements with Semitropic, ACWD has contracted for a combined total of 150,000 AF of storage capacity. As of January 1, 2019, the District has approximately 136,300 AF of water in storage at the Semitropic banking program. However, the maximum rate at which stored water can be returned to ACWD from Semitropic is constrained by ACWD-Semitropic contractual limitations. As shown in Table 11, under the most severe drought conditions, the maximum rate at which water can be returned to ACWD is 13,500 AF/yr.
Water Supply under Multiple Dry Year Conditions
Table 12 provides summaries of the projected supply availabilities under a long-term (five-year) drought for 2036-2040 demand conditions. This multiple year drought sequence is based on the 1987-1991 historical hydrologic conditions, which represents the most severe five-year drought on record (based on projected availability of ACWD’s supplies over the 1922-2003 hydrologic period). The results from this analysis indicate that ACWD’s water supplies may be significantly reduced during a multiple year drought. However, the supply reduction would not be as severe as during a single, critically dry year condition. As with the single dry year condition, both local groundwater storage and off-site groundwater storage in Semitropic will play key roles in offsetting shortfalls in the District’s other local and imported supplies.
23 SECTION 4 WATER SUPPLY AND DEMAND ANALYSES
The following provides a comparison of ACWD water supplies and projected future demands, including the demands associated with the proposed Project. The supply/demand comparisons are provided for normal, single year dry, and multiple dry year conditions.
NORMAL YEAR WATER SUPPLY
Table 13 provides a comparison of normal year water supply and demands under future levels of development in five-year increments from 2020 through 2040. As shown in the tables, ACWD’s projected supply under normal year conditions is sufficient to meet current and projected future demands, which include demands for this Project.
SINGLE DRY YEAR WATER SUPPLY
Table 14 documents the comparison of water supply and demand under a single critical dry year condition based on 1977 hydrologic conditions. As with the normal year conditions, the single dry year supply/demand comparison is provided in the same five-year increments between 2020 and 2040.
As shown in the table, ACWD anticipates facing a water supply shortage during single critical dry year supply conditions. This shortage is less than previously anticipated in previous forecasts due primarily to the reduction in forecast demands, discussed under Section 2 – Water Demands. District planning has held since the 1995 IRP that shortages anticipated during critical droughts of this magnitude and frequency (1 in 35 years) will be mitigated through a combination of demand management measures (including rationing) and purchases of dry year water through programs such as the Drought Water Bank (initiated during the 1987-1992 drought by the DWR).
MULTIPLE DRY YEAR WATER SUPPLY
Table 15 documents projected water supply and demand under an extended dry period (multiple year drought). As documented in the UWMP, ACWD recognizes the hydrology of 1987 to 1991 to be the most severe five-year period for the District’s imported and local supplies. The multiple year dry period was reviewed for the level of demand anticipated between the years of 2036 and 2040 as that is the highest level of demands anticipated during the next 20 years.
24 SECTION 5 SUMMARY AND CONCLUSIONS
1. The City of Union City has proposed the Station East Project which would add new development as well as redevelop portions of the existing Decoto Industrial Park. The Project includes the addition of 964 residential dwelling units, 31,020 ft2 of commercial space, and approximately 376,358 ft2 of landscaped areas, including public parks, paseos, semi-private and private open space areas, as well as other landscaped areas.
2. The total projected demand for the Project is approximately 103 AF/yr.
3. The Project demand is consistent with planning assumptions and is included in the District’s forecast and water supply planning established in the 2015 UWMP.
4. The District has diverse sources of supply that include imported water from the State Water Project and San Francisco Regional Water System, as well as local supplies from the Alameda Creek Watershed and underlying Niles Cone Groundwater Basin. Due to the configuration of the District’s water production facilities, the proposed Project would not be dependent on any single source of supply.
5. The District’s imported and local water supplies may be significantly cut back during droughts. In order to improve the District’s dry year reliability, the District has secured 150,000 AF of off-site storage capacity at the Semitropic Groundwater Banking Program in Kern County. The District currently has approximately 146,100 AF in storage at the Semitropic Bank.
6. Key uncertainties facing the District’s supplies include the effects of climate change as well as supply restrictions due to ongoing regulatory processes, endangered species and environmental protection. The District’s projected long-term average supply reliability from the State has been reduced from 72% to 62% of Maximum Table A Allocation, primarily as a result of Delta export pumping restrictions to protect endangered species.
7. Under normal year conditions, the District’s water supplies are projected to be sufficient to meet the future demands in the service area, including the Project’s demands.
8. The District’s UWMP identifies that the District may face water supply shortages during critically dry years. As described in the UWMP, the District would look to secure additional supplies through a DWR drought water bank or similar water purchase/transfer program under these severe drought conditions. The District may also implement a drought contingency plan, which would include provisions for the District customers to cut back on water use, the magnitude of which would depend on the severity of the shortage. Because the Project’s demands are consistent with the UWMP demand forecast, the development of the Project will not result in increased shortages from that which is already factored into the District’s planning. However, because the District anticipates potential future shortages under severe drought conditions, water supplies to the Project may be cut back during these severe dry year conditions. The level of cut back to the Project would be consistent with the
25 rest of the District’s customers and would depend on the magnitude of the dry-year shortage facing the entire District.
9. As part of the Project description, the Project shall be developed with water efficient plumbing fixtures and irrigation systems, including but not limited to those listed in Attachment D – Water Efficiency Measures for New Developments.
10. The determination of water supply sufficiency is based on the implementation of the water efficiency measures set forth in paragraph 9 above and these water efficiency measures must be included in the environmental analysis for this Project and in the City’s conditions of Project approval.
11. This water supply assessment is based on the proposed land use of the Station East Project, as provided to the District by the City of Union City (documented in Attachment A). If, prior to Project approval, the proposed land use within the Project area changes from what is currently incorporated in this water supply assessment, the District will evaluate the impacts that these changes may have on the District’s water supplies. In the event that the land use changes impact the conclusions of this water supply assessment, the District may require additional mitigation measures as a condition of providing water service to the Project. If the proposed land use changes occur after Project approval and approval of the final subdivision maps, the District will evaluate the potential water supply impacts of these changes, and may require additional mitigation as a condition of providing water service to those areas with the changed land use condition.
12. The determination made in this water supply and demand analysis is based on the circumstances as of the date this water supply assessment was approved. In the event that subsequent evaluation of District-wide demands and supplies in-light of the water supply uncertainties set forth in this water supply assessment indicates that there will be an imbalance between demands and supplies, the District may require additional mitigation for the Project. For example, if District supplies are not sufficient to meet the demands, as a condition of water service, the District may require the Project proponent to: 1) acquire a new water supply to offset the water supply impacts of the Project, and/or: 2) invest in District- wide conservation programming (above and beyond that which is planned by the District) to offset the increase in District-wide demands that are a result of the Project; and/or 3) provide other mitigations deemed necessary to offset specific impacts identified (such as purchasing storage and recovery capacity in Semitropic Groundwater Banking Program).
The District reserves the right to impose conditions that go beyond the conditions that the City of Union City may impose as part of the environmental analysis at the time the District provides a verification of sufficient supply for the Project and/or enters into a water service agreement with the developer to provide water service to the Project.
26 Table 1 ACWD Past and Current Water Use (Acre-Feet)
Water Use Category Fiscal Year 07-08 08-09 09-10 10-11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 18-19 Distribution System Single Family 17,100 24,600 24,100 21,500 21,800 21,700 23,200 21,600 16,600 14,400 17,400 17,200 Residential Multi-Family 7,200 8,100 7,400 7,600 7,500 7,600 8,200 8,100 7,100 6,900 7,100 7,300 Residential Commercial 5,200 5,100 4,700 4,700 3,800 5,000 5,000 4,600 4,400 4,700 4,900 4,800 Industrial 3,100 2,800 2,500 2,500 2,600 2,500 2,300 2,200 2,100 2,200 2,300 2,300 Institutional 2,100 2,100 1,800 1,700 1,900 2,000 1,800 1,300 1,000 1,300 1,400 1,400 Landscape 6,000 5,600 4,800 4,900 6,400 5,700 5,200 3,600 2,800 3,500 4,600 4,400 Other 100 200 100 200 100 200 200 200 200 200 200 200
Total Consumption 49,200 47,300 43,000 43,300 44,100 46,800 44,200 35,600 31,800 36,400 38,000 37,400 Unaccounted for 4,100 5,800 3,500 4,100 4,100 4,200 2,000 2,400 2,800 4,500 2,600 3,500 Water Distribution System 41,500 55,000 50,800 47,100 47,400 48,300 48,800 46,600 38,400 36,300 39,000 41,500 Total
Groundwater
System Private Groundwater 2,200 2,100 1,900 2,000 2,600 1,900 2,000 2,000 2,000 1,600 1,800 1,500 Groundwater
Reclamation -ARP Pumping 6,600 4,900 7,000 11,300 12,000 11,000 11,400 11,200 11,900 11,500 10,900 10,700 -Saline Outflow 7,400 7,400 6,800 6,100 4,700 3,600 300 2,200 4,900 8,500 7,400 7,700 Groundwater 19,900 16,200 14,400 15,700 19,400 19,300 16,500 13,700 15,400 18,800 21,600 20,100 System Total
Grand Total 71,200 65,200 62,800 66,800 67,600 65,300 60,300 53,800 55,000 60,600 61,600 61,400
Notes: 1. Annual consumption is based on units billed during the Fiscal Year (July 1 to June 30). The District uses a bi-monthly billing cycle. 2. All values rounded to the nearest 100 AF; total consumption values may not equal sum of individual components. 3. Multi-Family Residential, Commercial, Industrial, and Institutional categories do not include dedicated landscape irrigation water use within these categories. 4. Landscape water use includes all dedicated landscape accounts for Multi-Family Residential, Commercial, Industrial and Institutional customers. 5. Distribution System Total represents total water production, as reported in the District's Annual Groundwater Survey Reports. 6. Gross Non-Revenue Water is the difference between Distribution System Total and Total Measured Consumption, and includes distribution system losses; it is not the AWWA calculation for Distribution System Losses in Appendix G. 7. Groundwater System demands are based on annual reported values in the District’s Annual Survey Report on Groundwater Conditions. 8. Groundwater Reclamation demands represent groundwater system demands to protect and reclaim the groundwater system from saltwater intrusion. 9. Groundwater System demands do not include "Other Outflows" as reported in the District’s Annual Survey Report on Groundwater Conditions.
27 Table 2 Estimated Future Water Demands in the ACWD Service Area – Normal Year (AF/yr)
Year Water Use Category 2020 2025 2030 2035 2040
Distribution System Single Family Residential 22,700 22,800 22,900 22,700 22,600 Multi-Family 10,700 11,300 11,700 12,000 12,200 Residential Commercial 7,100 7,500 8,000 8,400 8,800 Industrial 4,400 5,000 5,300 5,400 5,500 Institutional 4,400 4,800 5,400 5,400 5,400
Other 300 300 300 300 300
Total Distribution 49,600 51,700 53,500 54,200 54,700 System Demand (without losses) Total Distribution 52,700 55,000 56,900 57,600 58,200 System Demand (with losses) 2011-2016 Drought (5,300) (3,000) (3,000) (3,000) (3,000) Demand Factor Additional (200) (400) (700) (900) (1,100) Conservation Program
Groundwater System Demand 16,200 16,200 16,200 16,200 16,200
Total ACWD 63,400 67,700 69,400 69,900 70,300 Forecast Demands
Notes: 1. All numbers are from the District’s 2015 UWMP. Forecast includes demand assumptions for the Project. 2. All values rounded to the nearest 100. Total values may not equal sum of individual components due to rounding errors. 3. Landscape Irrigation included within Multi-Family Residential, Commercial, Industrial, and Institutional categories 4. Adjustment for natural conservation (efficiency improvements due to plumbing code enhancements) is included in demand totals. 5. Total Distribution System Demand (with Non-Revenue Water) includes estimated Non-Revenue Water of 6%. 6. “2011-2016 Drought Demand Factor” is the estimated amount of demand reduction the District anticipates to remain after the drought ended. 7. Groundwater System Demands includes average annual values for: (1) private pumping (2,000 AF/yr), (2) ARP pumping (7,000 AF/yr), and (3) saline groundwater outflows (7,200 AF/yr).
28 Table 3 Estimated Future Water Demands in the ACWD Service Area – Critical Dry Year (AF/yr)
Year Water Use Category 2020 2025 2030 2035 2040
Distribution System Single Family Residential 22,700 22,800 22,900 22,700 22,600 Multi-Family 10,700 11,300 11,700 12,000 12,200 Residential Commercial 7,100 7,500 8,000 8,400 8,800 Industrial 4,400 5,000 5,300 5,400 5,500 Institutional 4,400 4,800 5,400 5,400 5,400
Other 300 300 300 300 300
Total Distribution 49,600 51,700 53,500 54,200 54,700 System Demand (without losses) Total Distribution 52,700 55,000 56,900 57,600 58,200 System Demand (with losses) 2011-2016 Drought (5,300) (3,000) (3,000) (3,000) (3,000) Demand Factor Additional (200) (400) (700) (900) (1,100) Conservation Program
Groundwater System Demand 12,300 12,400 12,600 12,700 12,900
Total ACWD 59,500 63,900 65,800 66,400 67,000 Forecast Demands
Notes: 1. All numbers are from the District’s 2015 UWMP. Forecast includes demand assumptions for the Project. 2. All values rounded to the nearest 100. Total values may not equal sum of individual components due to rounding errors. 3. Numbers do not reflect demand reductions resulting from SB-7. 4. Landscape Irrigation included within Multi-Family Residential, Commercial, Industrial, and Institutional categories. 5. Adjustment for conservation includes savings due to District-sponsored water conservation programs. 6. Total Distribution System Demand (with losses) includes estimated system losses of 8.4%. Distribution system losses are calculated as the difference between total production and total measured consumption and include water for fire suppression, distribution system flushing, distribution system and service line leaks, etc. 7. Groundwater System demands include: (1) private pumping, (2) ARP pumping, and (3) saline groundwater outflows.
29 Table 4 Estimated Future Water Demands in the ACWD Service Area – Multiple Dry Years (AF/yr)
Year Water Use Category 2036 2037 2038 2039 2040
Distribution System Single Family Residential 22,700 22,700 22,700 22,700 22,600 Multi-Family 12,000 12,100 12,100 12,200 12,200 Residential Commercial 8,500 8,600 8,600 8,700 8,800 Industrial 5,400 5,400 5,400 5,500 5,500 Institutional 5,400 5,400 5,400 5,400 5,400
Other 300 300 300 300 300
Total Distribution 54,300 54,400 54,500 54,600 54,700 System Demand (without losses) Total Distribution 57,900 58,000 58,000 58,100 58,200 System Demand (with losses) 2011-2016 Drought (3,000) (3,000) (3,000) (3,000) (3,000) Demand Factor Additional (1,100) (1,100) (1,100) (1,100) (1,100) Conservation Program
Groundwater System Demand 15,000 11,300 11,300 11,700 9,200
Total ACWD 68,800 65,200 65,200 65,700 63,300 Forecast Demands
Notes: 1. All numbers are from the District’s 2015 UWMP. Forecast includes demand assumptions for the Project. 2. All values rounded to the nearest 100. Total values may not equal sum of individual components due to rounding errors. 3. Adjustment for natural conservation (efficiency improvements due to plumbing code enhancements) is included in demand totals. 4. Total Distribution System Demand (with losses) includes estimated system losses of 6%. 5. “2011-2016 Drought Demand Factor” is the estimated amount of demand reduction the District anticipates to remain due to the recent drought. 6. Groundwater System demands include: (1) private pumping, (2) ARP pumping, and (3) saline groundwater outflows.
30 Table 5 Water Demands for Station East Project
GPD/ Demand estimate Element Planning units Unit (AF/yr) Residential Multi-Family (Apartments and 856 Residential 56 53 Condominiums) Units Multi-Family Residential 108 Residential 151 18 (Townhouses) Units
Building Area Commercial 31,020 0.104 4 (sq. ft.)
Other Lot Area (sq. 376,358 0.051 21 (park/landscape) ft.)
Estimated Total Project Demand (rounded) 97
Water Supplies Required (6% Unaccounted for Water) 103
Approximate peak day demand in mgd (1.6x peaking factor) 0.09
Notes: 1. Project details provided by City of Union City in WSA request letter. 2. Planning units for “Other (park/landscape)” provided by City of Union City from Open Space Calculations document created by Integral Communities
31 Table 6 Overview of Contracts and Permits for ACWD’s Existing Water Supplies
Maximum SUPPLY Ever Category Description Quantity COMPONENT Used (AF/Yr) Imported Supplies
In 1961, ACWD signed an agreement with the California State Department of Water Resources State Water for a maximum annual amount of 42,000 AF/yr Contract 42,000 Yes Project from the State Water Project (SWP). SWP water is delivered to ACWD via the South Bay Aqueduct. This contract expires in the year 2035.
In 2009, ACWD along with the other wholesale customers signed a new Master Sales Agreement with San Francisco. The new agreement has a term San Francisco of 25 years and provides a commitment from San Regional Water Contract Francisco to provide, collectively, up to 184 mgd to 15,344 Yes System its wholesale customers. ACWD’s contractual purchase amount is 13.76 mgd.
Local Supplies
ACWD applied for a water rights permit from the Alameda Creek Water- SWRCB in 1949, granted in 1951 (permit no. Diversions for rights 8428) to appropriate up to 40,000 AF/yr of 40,000 Yes Groundwater permit unappropriated water from the Alameda Creek for Recharge groundwater storage and replenishment.
ACWD received a water rights permit in from the Water- SWRCB in 1958 (permit no. 11320) to appropriate Del Valle rights up to 60,000 AF/yr of unappropriated water from 60,000 Yes Reservoir permit Arroyo Del Valle in the Alameda Creek Watershed for storage and later beneficial use.
Groundwater ACWD manages and protects the Niles Cone Storage in Niles Groundwater Basin for water supply under its Cone Alternative, including the Groundwater Groundwater Management Policy (adopted 1989, amended Basin Other N/A Yes 2001). This Policy is based on the statutory
authority granted to ACWD under the County Desalination of Water District Law; the Replenishment Assessment Brackish Act of ACWD; and local well ordinances. Groundwater
Banking / Transfers In 1996 and in 2001 entered into agreements with 13,500 Semitropic Water Storage District for 150,000 AF (maximum Semitropic of combined groundwater storage capacity for return Groundwater Contract banking of ACWD’s excess SWP supplies in wet quantity Yes Banking Program years. The banked water is to be returned to during ACWD in dry years via a series of exchanges. critically dry These banking agreements expire in the year 2035. years)
32 Table 7 Historical Water Supply Utilization by ACWD (AF/yr)
SWP San Recovered Total In- SWP Supply supplies Newark Net Local Fiscal Del Francisco from District delivered to used at Desal Groundwater Year Valle Regional Semitropic Water Semitropic ACWD Facility Recharge (2) Water GW bank Supply GW bank facilities 92-93 14,900 4,100 13,000 - 40,700 - 72,700 -
93-94 21,600 5,000 12,200 - 28,500 - 67,300 -
94-95 16,100 4,200 13,000 - 35,900 - 69,200 -
95-96 18,600 5,300 12,200 - 27,600 - 63,700 -
96-97 7,700 15,900 14,700 - 25,300 - 63,600 6,200
97-98 12,900 10,600 13,700 - 58,000 - 95,200 10,000
98-99 20,800 5,300 13,600 - 33,200 - 72,900 18,800
99-00 25,200 3,800 13,800 - 26,900 - 69,700 7,200
00-01 26,400 200 13,000 - 31,000 - 70,600 7,300
01-02 21,900 4,600 13,500 - 32,100 - 72,100 100
02-03 17,600 7,400 14,000 - 31,400 - 70,400 20,800
03-04 18,500 6,700 13,700 2,600 30,700 - 72,200 4,000
04-05 18,800 6,000 11,800 3,900 38,700 - 79,200 9,300
05-06 15,600 7,700 11,700 3,900 38,200 - 77,100 41,500
06-07 13,800 11,000 15,300 2,800 26,000 - 68,900 11,900
07-08 22,600 500 15,000 3,600 24,600 5,500 71,800 -
08-09 10,400 4,200 12,600 3,200 24,100 12,600 65,100 -
09-10 18,100 2,500 11,700 1,100 30,800 - 64,200 -
10-11 14,300 5,900 8,800 6,600 33,600 - 69,200 23,400
11-12 18,320 2,600 9,320 8,900 17,000 - 56,140 5,000
12-13 14,800 5,800 10,000 8,100 12,200 2,000 52,900 7,500
13-14 16,800 1,400 13,100 8,400 12,900 3,000 55,300 -
14-15 8,900 1,200 8,800 8,200 23,300 13,200 63,500 -
15-16 2,300 5,500 6,700 7,600 30,100 13,300 65,500 8,900
16-17 4,900 9,000 6,700 7,800 33,400 3,500 65,300 20,800
17-18 15,300 2,100 8,600 7,100 22,400 - 55,500 7,900
18-19 9,000 4,500 8,800 6,700 26,900 5,000 60,900 6,100
1. All values rounded to the nearest 100. Total values may not equal sum of individual components due to rounding errors. 2. Recharge figures less evaporation and other losses.
33 Table 8 Summary of Potential Future Factors that may Influence ACWD Water Supply Reliability
Factor SUPPLY Legal/Environmental Water Quality Climatic Imported Supplies ESA* requirements may Potential seawater intrusion Supply is dependent on -State Water Project constrain Delta pumping impacts if Delta Levees fail. hydrologic conditions
- San Francisco ESA requirements may require Supply is dependent on None anticipated Regional Supply additional reservoir releases hydrologic conditions
Local Supplies ESA requirements may impact Supply is dependent on groundwater recharge hydrologic conditions operations Upstream water management - Groundwater activities and/or land use Sea level rise may Recharge Upstream water management activities may impact water constrain usable storage activities and/or agreements quality of Niles Cone with upstream agencies may Groundwater Basin impact supply availability Supply is dependent on - Groundwater Storage None anticipated None anticipated availability of water to store in wet years
ESA requirements may require Supply is dependent on None anticipated - Del Valle downstream flow releases hydrologic conditions
Supply is dependent on - Desalination None anticipated None anticipated local groundwater conditions - Recycled Water None anticipated None anticipated None anticipated Banking/Transfers Delta pumping constraints may impact ability to recover water through SWP exchanges Supply is dependent on Banked groundwater may availability of water to - Semitropic Banking require treatment Sustainable Groundwater store in wet years Management Act (SGMA) could impact future operations of the bank. * Endangered Species Act
34 Table 9 State Water Project Delivery Reliability Reports (DRR) Statistics
2002 2005 2007 2009 2011 2013 2015 2017 Report Report Report Report Report Report Report* Report* Average % of Full Allocation 72% 69% 63% 60% 60% 60% 62% 62% in year of report Biological Opinions Changes in Wanger Updates in on Primary modeling Decision assumptions Salmonids No No No N/A assumptions + limited and inputs cause for & Smelt + change change change and Climate to change expanded demands Change simulations Climate Change * The 2015 Report and 2017 Report were titled “State Water Project Delivery Capability Report,” or DCR.
35 Table 10 Projected Normal Year Supply
Year SUPPLY/DEMAND 2020 2025 2030 2035 2040 SUPPLY COMPONENT Imported Supplies - State Water Project 27,500 27,500 27,500 27,500 27,500 - San Francisco Regional 15,400 15,400 15,400 15,400 15,400 Total Imported Supplies 42,900 42,900 42,900 42,900 42,900
Local Supplies - Groundwater Recharge 24,200 23,900 23,600 23,300 23,000 - Groundwater Storage 0 0 0 0 0 - Del Valle 5,000 5,000 5,000 5,000 5,000 - Desalination 5,100 5,100 5,100 5,100 5,100 - Recycled Water 0 0 0 0 0 Total Local Supplies 35,300 34,000 33,700 33,400 33,100
Banking/Transfers - Semitropic Banking 0 0 0 0 0
TOTAL SUPPLY 77,200 76,900 76,600 76,300 76,000 *Normal Year conditions based on projected water supply availability under 1971 hydrologic conditions.
Table 11 Projected Critical Year Supply
Year SUPPLY/DEMAND 2020 2025 2030 2035 2040 SUPPLY COMPONENT Imported Supplies - State Water Project 3,400 3,400 3,400 3,400 3,400 - San Francisco Regional 8,200 8,500 8,900 9,300 9,600 Total Imported Supplies 11,600 11,900 12,300 12,700 13,000
Local Supplies - Groundwater Recharge 15,100 15,200 15,200 15,200 15,200 - Groundwater Storage 10,000 10,000 10,000 10,000 10,000 - Del Valle 0 0 0 0 0 - Desalination 5,100 5,100 5,100 5,100 5,100 - Recycled Water 0 0 0 0 0 Total Local Supplies 30,200 30,300 30,300 30,300 30,300
Banking/Transfers - Semitropic Banking 13,500 13,500 13,500 13,500 13,500
TOTAL SUPPLY 59,500 63,900 65,800 66,400 67,000 *Critical Dry Year conditions based on projected water supply availability under 1977 drought conditions.
36 Table 12 Projected Multiple Dry Year Supply
Year SUPPLY/DEMAND 2036 2037 2038 2039 2040 SUPPLY COMPONENT Imported Supplies -State Water Project 9,100 6,400 25,900 11,200 6,700 - San Francisco Regional 12,600 9,400 9,500 9,100 9,200 Total Imported Supplies 21,700 15,800 35,400 20,300 15,900
Local Supplies - Groundwater Recharge 16,100 16,600 11,900 16,000 14,800 - Groundwater Storage 7,300 9,900 0 7,600 4,400 - Del Valle 900 300 500 200 4,600 - Desalination 5,100 5,100 5,100 5,100 5,100 - Recycled Water 0 0 0 0 0 Total Local Supplies 29,400 31,900 17,500 28,900 28,900
Banking/Transfers - Semitropic Banking 14,900 13,500 24,400 16,100 13,600
TOTAL SUPPLY 66,000 65,200 65,200 65,700 63,300 *Multiple Dry Year conditions based on projected water supply availability under 1987-91 drought conditions.
37 Table 13 Water Supply and Demand Comparison: Normal Year
Year SUPPLY/DEMAND 2020 2025 2030 2035 2040 Total Supply 77,200 76,900 76,600 76,300 76,000 Forecast Demands 62,900 67,000 68,600 69,300 69,800 Anticipated Shortage none none none none none Notes: 1. All values rounded to the nearest 100 AF. 2. Forecast Demands include Project demands.
Table 14 Water Supply and Demand Comparison: Critical Dry Year
Year SUPPLY/DEMAND 2020 2025 2030 2035 2040 Total Supply 55,300 55,700 56,100 56,500 56,800 Forecast Demands 59,500 63,900 65,800 66,400 67,000 Anticipated Shortage (4,200) (8,200) (9,700) (9,900) (10,200) Notes: 1. All values rounded to the nearest 100 AF. 2. Forecast Demands include Project demands. 3. Critical Dry Year conditions are based on projected water supply availability under 1977 drought conditions.
Table 15 Water Supply and Demand Comparison: Multiple Dry Year
Year SUPPLY/DEMAND 2036 2037 2038 2039 2040 Total Supply 66,000 61,200 77,300 65,300 58,400 Forecast Demands 68,800 65,200 65,200 65,700 63,300 Anticipated Shortage (2,800) (4,000) none (400) (4,900) Notes: 1. All values rounded to the nearest 100 AF. 2. Forecast Demands include Project demands. 3. Multiple Dry Year conditions are based on projected water supply availability under 1987-91 drought conditions; supply includes access to stored water in Semitropic
38
Figure 1 ACWD Service Area and Station East Project Location Map
39 REFERENCES
ASSOCIATION OF BAY AREA GOVERNMENTS, 2009. Projections and Priorities 2009: Building Momentum.
ALAMEDA COUNTY WATER DISTRICT, 1995. Integrated Resources Planning Study.
ALAMEDA COUNTY WATER DISTRICT, 2001. Groundwater Management Policy.
ALAMEDA COUNTY WATER DISTRICT, 1999-2018. Groundwater Survey Reports.
ALAMEDA COUNTY WATER DISTRICT, 2015. Urban Water Management Plan, 2015-2020.
ALAMEDA COUNTY WATER DISTRICT, 2020. April 21, 2020. Letter to City of Union City in request for 30-day extension to complete Water Supply Assessment (sent April 21, 2020).
CALIFORNIA DEPARTMENT OF WATER RESOURCES, 2005. The State Water Project Deliver Reliability Report 2005
CALIFORNIA DEPARTMENT OF WATER RESOURCES, 2007. The State Water Project Deliver Reliability Report 2007
CALIFORNIA DEPARTMENT OF WATER RESOURCES, 2009. The State Water Project Deliver Reliability Report 2009
CALIFORNIA DEPARTMENT OF WATER RESOURCES, 2015. The State Water Project Delivery Capability Report 2015
CALIFORNIA DEPARTMENT OF WATER RESOURCES, 2017. The State Water Project Delivery Capability Report 2017
CALIFORNIA DEPARTMENT OF WATER RESOURCES, 2016. DWR Bulletin 118 – Update 2016 California’s Groundwater, Working Toward Sustainability
CITY OF UNION CITY, 2020. February 18, 2020. Letter to ACWD in request for Water Supply Assessment (received February 18, 2020).
INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE, 2007, Climate Change 2007 – The Physical Science Basis
PACIFIC INSTITUTE, 2005. Climate Change and California Water Resources: A Survey and Summary of the Literature.
STATE WATER RESOURCES CONTROL BOARD, 2010, Development of Flow Criteria for the Sacramento-San Joaquin Delta Ecosystem
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ATTACHMENT A LETTER OF REQUEST FROM CITY OF UNION CITY FOR WATER SUPPLY ASSESSMENT AND REQUEST FROM ALAMEDA COUNTY WATER DISTRICT FOR 30-DAY EXTENSION TO COMPLETE WATER SUPPLY ASSESSMENT
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ATTACHMENT B ACWD URBAN WATER MANAGEMENT PLAN 2015-2020
UWMP not included with this version of the document due to the size of the attachment. The UWMP is posted on the District’s website at https://www.acwd.org/365/Urban-Water- Management-Plan
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ATTACHMENT C ACWD WATER SUPPLY CONTRACTS
State Water Project Water Supply Contract and San Francisco Water Supply Contract can be found in Appendix A-1 and A-2 of the UWMP, respectively.
They may also be found at https://www.acwd.org/730/Water-Supply-Contracts
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ATTACHMENT D WATER EFFICIENCY MEASURES FOR NEW DEVELOPMENTS
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