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APPENDIX K
WATER SUPPLY ASSESSMENT
1
SB 610 Water Supply Assessment
For
Oyster Point Development Project
Draft August 1, 2017
Prepared by
California Water Service
341 North Delaware Ave
San Mateo, California 94401
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TABLE OF CONTENTS
Introduction and Project Description .............................................................................................. 3
Oyster Point Development Project Water Demand Forecast .......................................................... 7
South San Francisco District Background Information ................................................................ 10
South San Francisco District Water Demand ............................................................................... 11
South San Francisco District Water Supply.................................................................................. 20
Purchased Water ............................................................................................................... 20
Groundwater ..................................................................................................................... 25
Future Possible Supplies...………………………………………………………………………30
Recycled Water ................................................................................................................. 30
Desalinated Water……………………………………………………………………….32
Water Transfers………………………………………………………………………….34
Water Supply Reliability Assessment…………………………………………………………... 37
Normal Water Year ........................................................................................................... 41
Single Dry Year ................................................................................................................ 42
Multiple Dry Years (3)………..………………………………..……. …………………42
Summary of Supply and Demand Analysis……………………………………………………..47
Conclusions……………………………………………………………………………………...48
References……………………………………………………………………………………….49
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Introduction and Project Description
The City of South San Francisco (City) has requested California Water Service (Cal Water)
prepare an updated Water Supply Assessment (WSA) in accordance with California SB 610
requirements for the proposed revised Oyster Point Development Project (OPDP). In June 2011,
Cal Water prepared a WSA for the Oyster Point Business Park and Marina Area.
The site of the OPDP, including the Phase I Project and all subsequent phases of development is
part of the City’s “East of 101” planning area. The 81 acre plan site is located about 3/4 of a mile
east of Highway 101, at the eastern end (Bay side) of Oyster Point and Marina Boulevards. The
OPDP covers 25 acres of the total plan area. It contains privately owned five single-story light-
industrial buildings at 375/377, 379, 384, 385 and 389 Oyster Point Boulevard that were
developed in the early 1980s totaling 403,212 square feet of space and surrounding parking.
Presently, these buildings continue to be occupied by a variety of light industrial, office, and
research and development (R&D) tenants.
Other than roadway elements, the 48 acre Oyster Point Marina constitutes the remainder of the
total plan area. This land served as a municipal landfill for the City of South San Francisco from
1956 until it stopped accepting waste in 1970. The Marina is owned by the City of South San
Francisco and managed through a Joint Powers Agreement with the San Mateo County Harbor
District. This area includes a variety of uses: a dry boat storage area, a marine support services
building, two small office buildings, Oyster Point Inn, a 30 room inn and banquet hall, Oyster
Point Bait and Tackle shop, a boat and motor mart and the Oyster Point Yacht Club, totaling
74,360 square feet. The remaining area is vacant or serves as parking for the docks, boat ramp,
and the Bay Trail at the Oyster Point Marina.
The Oyster Cove Marina is privately owned and located to the west of the Oyster Point Business
Park; it contains 235 berths. The Oyster Point Marina is located on the north side of the Oyster
Cove Marina area and contains 600 berths, a boat ramp, fuel dock and fishing pier.
The proposed OPDP is to be implemented in four (4) phases and includes demolition of existing
commercial and recreational buildings. The Existing Conditions Aerial photo (SKS June 1, 2010)
and Proposed Development Phases (Shorenstein/SKS September 10, 2009) show location
features and development Phases. Table 1 provides the proposed development schedule for each
of the four phases. It also shows the difference between the OPSP and the OPDP in terms of type
of development. Figure 1 shows the development plan layout.
As proposed, the OPDP will be a public and private redevelopment comprised of the uses shown
in Table 1. The total for all Office and R&D building area is 1,550,000 square feet (compared to
2,250,000 square feet in the 2011 plan). Newly proposed are 1,191 multifamily residential units.
Unchanged are 20,000 square feet of commercial space and a 350 room hotel. All development
work is to be started in 2018 and completed between the 3rd quarter of 2019 and the 2nd quarter
of 2020.
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Table 1: Oyster Point Development Project Summary
Phase 2011 Specific Plan 2017 Proposed Project Construction Start
Estimated Date of
Completion
1 508,000sf Office/R&D 508,000 sf Office/R&D April, 2018 3rd Qtr 2019
2 581,000sf Office/R&D 1,042,000 sf Office/R&D October, 2018 2nd Qtr 2020
3 581,000sf Office/R&D
600 residential units,
20,000 sf Commercial May, 2018 1st Qtr 2020
4 580,000sf Office/R&D 591 residential units August, 2018 3rd Qtr 2020
Hotel 350 Rooms 350 Rooms October, 2018 2nd Qtr 2020
Figure 1: Proposed Oyster Point Development (2017)
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Following is additional information on the proposed project:
Private development including new office/research and development (R&D) buildings in the
western portion of the site:
Demolition of the existing inn located at 425 Marina Drive, the office buildings at 360 Oyster
Point Boulevard and 401 Marina Boulevard, the boat and motor mart at 671 Marina
Boulevard, the Yacht Club at 911 Marina Boulevard, and the light-industrial buildings at
375-389 Oyster Point Boulevard,
New public roadway alignment (and utility infrastructure) of Oyster Point Boulevard and
Marina Drive, including relocation of sewer pump station #1 adjacent to 377 Oyster Point
Boulevard,
Each phase will include or have access to courtyards, plazas, shuttle bus stops, and/or
structured parking,
Dedication and construction of an approximately 3.1 acre parcel for use as waterfront public
open space.
Public redevelopment including public open space, recreation fields, marina improvements, and
a hotel:
A hotel with a total of 350 rooms and 40,000 square feet of retail/restaurant, as well as
replacement of the Yacht Club (4,000 square feet) and maintenance building (2,500 Square
feet),
A recreation or open space field,
Reconfiguration of parking adjacent to the new ferry terminal and shuttle bus turnaround
proposed with the ferry terminal,
Improvements to the Bay Trail and surrounding open space throughout Oyster Point Marina
and the proposed office/R&D Project (subject to BCDC Guidelines and input),
Possible changes to two of the docks in the Oyster Point Marina, which could include
removal and replacement,
Enhancement (landscape and other cosmetic improvements) of existing uses at the eastern
end of Oyster Point in conjunction with required landfill cap repairs, and
Roadway connections to the previously permitted South San Francisco Ferry Terminal.
Site preparation and/or construction on the former landfill site could involve disturbance and
relocation of landfill refuse on- or off-site.
Reconfiguration of Marina Boulevard and a portion of Oyster Point Boulevard.
New roadway construction will include bicycle lanes, sidewalks and street trees.
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Utilities will be provided in the new roads and will be sized for the full build-out of all
phases including sewer, water, fire water, and a joint trench for PG&E and telecom.
Parking lot adjacent to the west basin of Oyster Point Marina will be reconstructed after
landfill cover improvements have been completed to access the new Marina Boulevard
configuration.
A 3-acre site to the east of the Office/R&D buildings will be graded and constructed as a
sports field complex or flexible open space - to be determined by City.
A 3.1-acre waterfront site to the north and east of the Oyster Point Boulevard and Marina
Boulevard intersection will be graded and landscaped per City Specifications and BCDC
design guidelines.
Off-street pedestrian paths (including new portions of the Bay Trail) will connect the ferry
terminal to the existing Bay Trail and to the eastern edge of the Plaza in Phase I and to Gull
Drive to the south of Phase I.
The 4.7 acre site to the east of the sports fields is for the hotel and retail space.
The OPDP is not specifically discussed in Cal Water’s 2015 South San Francisco (SSF) District
Urban Water Management Plan (UWMP), which was adopted in June 2016; therefore, its water
requirements and how they would be met are addressed in this WSA. The SSF District UWMP
document provides historic and forecasted water demand and supply data and analyses and can
be referenced for more detailed information on those topics. Cal Water updates its Urban Water
Management Plans every three to five years.
Senate Bills 610 (Chapter 643, Statutes of 2001) (SB 610) and Senate Bill 221 (Chapter 642,
Statutes of 2001) (SB 221) amended state law, effective January 1, 2002, to improve the link
between information on water supply availability and land use development decisions made by
cities and counties. SB 610/SB 221 are companion measures that require detailed information
regarding water supply availability be provided to local public agency decision-makers prior to
approval of development projects that meet or exceed any of the following criteria:
1. A residential development of more than 500 dwelling units.
2. A shopping center or business establishment employing more than 1,000 persons or having
more than 500,000 square feet.
3. A commercial office building employing more than 1,000 persons or having more than
250,000 square feet of floor space.
4. A hotel or motel with more than 500 rooms.
5. An industrial, manufacturing or processing plant or industrial park planned to house more
than 1,000 persons occupying more than 40 acres of land or having more than 650,000
square feet of floor area.
6. A mixed-used project that includes one or more of the projects specified above.
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7. A project that would demand an amount of water equivalent to, or greater than the amount of
water required by a 500 dwelling unit project.
Since the proposed OPDP exceeds criteria 1 and 3 above, a SB 610 WSA and a SB 221
verification document are required.
A SB 610 WSA must address the adequacy of the water supply to meet estimated demands of the
proposed project over the next 20 years in addition to those of Cal Water’s existing customers
and other anticipated future users under normal, single dry year and multiple dry year conditions.
(Water Code §10911(a).) SB 610 and SB221 require that the information developed to address
the adequacy of the water supply question be included in the administrative record that serves as
the evidentiary basis for an approval action by the local public agency.
Both state bills recognize local control and decision-making regarding the availability of water
for projects and the approval of projects. Under SB 610, water supply assessments must be
furnished to local governments for inclusion in any required California Environmental Quality
Act (CEQA) documents. Water Code 10910 (a) requires that any city or county that determines
that a project, as defined in Section 10912, is subject to CEQA shall comply with the
requirements of this part of the water code. Under SB 221, approval by a city or county of certain
residential subdivisions requires an affirmative written verification of sufficient water supply. An
SB 221 verification document is required for tentative tract map approval.
In May 2017, the City requested Cal Water prepare an updated SB 610 WSA for the OPDP.
Water Code 10910(g) requires the water supplier to prepare the assessment within 90 days of
request.
Cal Water adopted its current SSF District UWMP for the District in June 2016. Per Section
10910(c) (3) of the Water Code, this water supply assessment is based on information contained
in the UWMP, updated water demand data for 2016 and other sources cited here.
Following is a projection of OPDP projected water demands and a description and assessment of
the water supply to meet those and other forecasted demands in the SSF District in accordance
with the requirements of SB 610.
Oyster Point Development Project Water Demand Forecast
For the proposed new facilities, water usage rates for new office space, R&D laboratories,
commercial and retail uses and landscape irrigation are initially based on those for similar
existing facilities in the Oyster Point area. Later in the WSA, they are adjusted to reflect the
progress made in the last 6 years in implementing use of water conserving fixtures, appliances
and practices.
In the 2011 WSA, water use data developed in the December 2008 South San Francisco Gateway
Business Park WSA, were obtained for specific buildings along with interior square footage. The
following is a summary of this data.
For the period from July 2007 – June 2008 (1 year or 365 days), total internal metered water use
for five existing buildings at 700, 1000, 750, 800 and 850 Gateway Boulevard was 3,392,180
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gallons for an area of 234,013 square feet. Overall average annual day water use was 0.04
gallons/day/ft2.
The existing building at 700 Gateway Blvd is nearly all office space use. The building area is
55,098 square feet and annual water use from July 2007 – June 2008 was 722, 568 gallons or
0.036 gallons/day/ft2.
The existing building at 800 Gateway Blvd is nearly all biotechnology research and development
laboratory space. The building area is 45,400 square feet and annual water use from July 2007 –
June 2008 was 1,039,720 gallons or 0.063 gallons/day/ft2.
For the July 2007 – June 2008 period, total landscape irrigation water use was 7,219,192 gallons
for an area of 250,143 square feet. Average annual day irrigation water use was: 0.079
gallons/day/ft2.
Estimating water usage for commercial, retail, restaurants and hotels on a gallons/square feet
basis requires characterizing the type and mix of businesses anticipated in the development. If
the commercial/retail/restaurant/hotel mix has a higher concentration of higher water using
businesses such as supermarkets, restaurants, coffee shops, health clubs, etc., the water use factor
will be significantly higher than a mix largely comprised of dry goods retail activities such as
clothing, shoes, jewelry, sporting goods, drug stores, bookstores, etc.
For another development project in Cal Water’s Dominguez District in Torrance, CA, PCR
Services Corporation (PCR) using data derived by the County Sanitation Districts of Los
Angeles (CSDLA) developed a table of estimated water demand for a variety of commercial
activities.
Since there was good agreement between the estimate of residential water usage derived from
Cal Water data and those developed by PCR using CSDLA data, estimates of water demand for
commercial activities developed by PCR using CSDLA factors are used here for the OPDP and
are summarized below.
PCR Commercial Activities Water Use Factors
Average Use
Category gallons/sq ft/day
Retail:
Shopping center 0.358
Electronic store 0.110
Home Improvement 0.110
Home Furnishings 0.110
Office Supplies 0.110
Supermarket 0.65
Restaurants: 1.10
Hotels: 0.50
The estimated average water demand for commercial which is assumed to be 70% dry retail and
30% restaurant uses is 0.40 gpd/ft2 based on using 0.3 x 1.10 + 0.110 x 0.70 = 0.40 gpd/ft2.
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The estimated water demand for multi-family dwelling units is based on data obtained from the
SSF 2010 and 2015 UWMPs. The 2010 UWMP indicated that US Census Bureau determined
there were 6,434 multi-family dwelling units in the district. Actual water use for those dwelling
units was 399 acre-feet per year (AF/yr). This equals 55.36 gallons per day per dwelling unit
(gpd/DU). The 2015 actual water use per multi-family dwelling unit was 348 AF/yr – a decrease
of 51 AF/yr due in part to implementation of demand reduction measures by residents prompted
by Cal Water conservation programs designed to meet state mandated water use reduction
targets. The estimated annual growth rate of population for the SSF District based on the 2015
UWMP is 0.72% or for the five year period from 2010 to 2015 an estimated 3.6%. If 80% of that
population growth occurred in multi-family dwelling units, that would be equivalent to an
increase in multi-family dwelling units of 2.88% resulting in an estimated total number of 6,619
dwelling units. Hence, the average water use in 2015 would be 46.9 gpd/DU.
The irrigated landscape water demand in the 2011 WSA was determined to be 0.079 gpd/ft2
based on historical application rates. For the OPDP, half the planned landscaping is to be drought
resistant, so a rate of 0.040 gpd/ft2 is used here.
Historic water use factors for estimating water demands for various types of development in the
2011 Oyster Point Specific Plan WSA do not take into account the last 6 years of progress in
installing water conserving fixtures and appliances and compliance with water use reduction
practices. All of these will be incorporated into the OPDP. It assumed here that this will reduce
water use rates by an average of 20%, which was the State of California’s mandated water use
reduction during the 2012 – 2015 drought. In another Cal Water WSA, a more detailed analysis
of the reductions of water use by newer toilets, urinals, showers, water faucets and irrigation
systems showed reductions in use rates greater than 20%.
The estimated water demand for the OPDP using historic water use factors is presented in Table
2 for all four phases which is to be completed in 12 -15 months.
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Table 2:Oyster Point Redevelopment Project Estimated Water Demand*
Phase
Implementation
Period New Use
Existing Use
Area (ft2)
New Area
(ft2) or
Number of
Residential
Dwelling
Units
Net Area
Increase
(ft2)
Unit Water
Demand
(gpd/ft2 or
gpd/DU)
Net
Water
Demand
Increase
(gpd)
1 Apr 2018 - Oct 2019 Office 66,420 148,000 81,580 0.036 2,937
R&D 360,000 360,000 0.063 22,680
Commercial 74,360 0 -74,360 0.400 -29,744
Total 508,000 367,220 -4,127
2 Oct 2018 - Jun 2020
Office 112,264 312,600 200,336 0.036 7,212
R&D 729,400 729,400 0.063 45,952
Commercial 74,360 0 -74,360 0.400 -29,744
Total 1,042,000 23,420
3 May 2018 - Mar 2020
Residential 600 NA 55.36 33,216
Commercial 20,000 20,000 0.400 8,000
Office 112,264 0 -112,264 0.036 -4,042
Total 37,174
4 Aug 2018 - Jun 2020
Residential 591 NA 55.36 32,718
Hotel 320,000 320,000 0.500 160,000
Office 112,264 0 -112,264 0.036 -4,042
Total 188,676
All Apr 2018 - Jun 2020
Irrigated
Landscaping 130,680 847,420 716,740 0.040 28,670
All Project Total 273,814
*As noted, historic unit water demand factors were used to prepare Table 2.
Following is the water conservation adjustment to the estimated total project demand.
Using the 20% demand reduction factor previously referenced, the estimated increase in water
demand for all four phases of the OPDP at the end of the 2nd quarter in 2020 is 273,814 gpd x
0.80 = 219,051 gpd or 245.4 AFY.
In the 2011 Oyster Point Specific Plan WSA, the estimated total for all four phases was 239,023
gpd. The estimated decrease in demand for the revised development plan is 19,972 gpd or 22.4
AFY.
South San Francisco District Background Information
The South San Francisco (SSF) District is located in northern San Mateo County approximately
six miles south of the City of San Francisco. The district serves the communities of South San
Francisco, Colma, a small portion of Daly City, and an unincorporated area of San Mateo County
known as Broadmoor, which lies between Colma and Daly City. The South San Francisco
District was formed by Cal Water in 1931 with the purchase of the South San Francisco Water
Company from Pacific Water Company.
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Figure 2 is a map showing the SSF District’s service areas.
Figure 2: South San Francisco District
Cal Water designates customer classifications as follows:
Single Family Residential
Multifamily Residential
Commercial
Industrial
Government
Other
A variety of land uses exist in the SSF District service area. Within the City of South San
Francisco, 28 percent of the land is residential, 21 percent industrial, 7 percent commercial, 11
percent is vacant and agricultural land and the balance is for public and utility use. In the City of
Colma, approximately 77 percent of the land is used for cemeteries. The balance of the land is
for residential, commercial, and public use. The Broadmoor area is primarily residential.
South San Francisco District Water Demand
Actual water use in the SSF District in 2015 by customer category is shown in Table 4. Total
system demand in 2015 was 7,064 AF. District water use in 2015 was strongly affected by the
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Drought Emergency Regulation adopted by the State Water Resources Control Board in May of
2015 (SWRCB Resolution No. 2015-0032). The Drought Emergency Regulation mandated
urban retail water suppliers reduce potable water use between June of 2015 and February of 2016
by percentages specified by the State Water Resources Control Board. The South San Francisco
District was ordered to reduce potable water use by 8 percent over this period relative to use over
the same period in 2013. Between June and December 2015, water use in South San Francisco
decreased by 21.7% compared to 2013.
Table 4: SSF District Demands for Potable Water
User Category
2015 Actual
(AF)
Single Family 2,404
Multi-Family 348
Commercial 3,212
Industrial 663
Institutional/Governmental 219
Other 16
Losses 201
Total 7,064
Residential customers account for approximately 86.6 percent of services and 40 percent of
water use in the District, most of which is single-family residential water use. Figure 3 shows
the distribution of services in 2015. Figure 4 shows historical water sales by customer category.
Figure 3: Distribution of Services in 2015
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Figure 4: Water Use by Customer Category
Projected Potable Water Demand
Projected normal year potable water demands by customer categories through 2040 are shown in
Tables 5. Future demands are estimated as the product of future services and expected water use
per service.
Table 5: SSF District Projected Potable Water Demands
Use Category (AF)
2020 2025 2030 2035 2040
Single Family 3,159 3,125 3,124 3,146 3,180
Multi-Family 402 394 396 404 417
Commercial 3,698 3,723 3,764 3,800 3,839
Industrial 695 730 768 807 848
Institutional/Governmental 371 367 363 360 358
Other 15 15 15 15 15
Losses 220 226 232 238 244
Total 8,560 8,580 8,662 8,770 8,901
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Future services are based on historical growth rates in the District. Single-family residential
services are projected using the historical growth rate for the last 20 years while multi-family
services are projected using the 5-year historical growth rate. Commercial and industrial
services are projected using the historical growth rate for the past 15 and 20 years, respectively.
The forecast assumes no change in the number of institutional services. The projected average
annual growth rate in services across all customer categories is approximately 0.5 percent.
Historical and projected services are shown in Figure 5. Also shown in the figure is the services
projection from Cal Water’s 2009 Water Supply and Facility Master Plan (WSFMP).
Figure 5: SSF District Historical and Projected Services
Expected water use per service, shown in Figure 6, is based on weather-normalized historical
use, adjusted for future expected water savings from plumbing codes and District conservation
programs. Weather normalization of historical use was done econometrically using the
California Urban Water Conservation Council GPCD Weather Normalization Methodology.
Expected water savings from plumbing codes are presented in Section 4.4 of the 2015 UWMP.
Expected water savings from District conservation programs and projected compliance with the
District’s SB X7-7 2020 per capita water use target are discussed in Chapter 9 of the 2015
UWMP. The projected trend in average use per service shown in Figure 6 does not account for
possible effects of climate change on future demand. The potential effects of climate change are
discussed in Section 4.6 of the UWMP.
Projected water uses in Table 5 and Figure 6 are based on unrestricted demands under normal
weather conditions. Demands are assumed to partially rebound by 2020 from 2015 levels due to
the State Water Resources Control Board ending its mandatory water use reductions. The
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difference between actual and projected demands in 2020 will depend in part on how water use
changes without state mandated reductions.
Figure 6: Historical and Projected Average Use per Service in Gallons per Day
Future Water Savings
The projections of future water use in Table 5 include expected water savings from plumbing
codes and appliance standards for residential and commercial toilets, urinals, clothes washers,
dishwashers, and showerheads. These savings are called passive water savings in contrast to
savings from water supplier conservation programs, which are called active water savings.
Active water savings from the South San Francisco District’s implementation of demand
management measures are discussed in Chapter 9 of the UWMP. Estimates of passive water
savings were developed with the Alliance for Water Efficiency’s Water Conservation Tracking
Tool using data on the vintage, number, and water using characteristics of residences and
businesses within South San Francisco District’s service area. They are shown in Table 6.
Table 6: Projected SSF District Passive Water Savings
2015 2020 2025 2030 2035 2040
Passive
Savings
(AF)
10 163 289 391 475 544
The following codes and standards form the basis for estimated future passive water savings:
AB 715 enacted in 2007
U.S. Department of Energy water use standards for residential and commercial
clothes washers and dishwashers
CalGreen Code requirements for maximum indoor water consumption of plumbing
fixtures and fittings in new and renovated properties.
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SB 407 mandates that buildings in California come up to current State plumbing
fixture standards within this decade. Noncompliant plumbing fixtures include:
o Toilets manufactured to use more than 1.6 gallons of water per flush
o Urinals manufactured to use more than one gallon of water per flush
o Showerheads manufactured to have a flow capacity of more than 2.5 gallons
per minute
o Interior faucets that discharge more than 2.2 gallons of water per minute.
For single-family residential property, the compliance date is January 1, 2017. For multi-family
and commercial property, it is January 1, 2019. In advance of these dates, the law requires
effective January 1, 2014 for building alterations and improvements to all residential and
commercial property that water-conserving plumbing fixtures replace all noncompliant plumbing
fixtures as a condition for issuance of a certificate of final completion and occupancy or final
permit approval by the local building department.
SB 407 also requires effective January 1, 2017 that a seller or transferor of single-family
residential property disclose to the purchaser or transferee, in writing, the specified requirements
for replacing plumbing fixtures and whether the real property includes noncompliant plumbing.
Similar disclosure requirements go into effect for multi-family and commercial transactions
January 1, 2019. SB 837, passed in 2011, reinforces the disclosure requirement by amending
the statutorily required transfer disclosure statement to include disclosure about whether the
property is in compliance with SB 407 requirements. If enforced, these two laws will require
retrofit of non-compliant plumbing fixtures upon resale or major remodeling for single-family
residential properties effective January 1, 2017 and for multi-family and commercial properties
effective January 1, 2019.
California has also adopted regulations governing the future use of landscape water use.
The California Water Commission approved the State’s updated Model Water
Efficient Landscape Ordinance (MWELO) on July 15, 2015. The updated MWELO
supersedes the State’s MWELO developed pursuant to AB 1881. Local agencies
have until December 1, 2015 to adopt the MWELO or to adopt a Local Ordinance
which must be at least as effective in conserving water as MWELO. Local agencies
working together to develop a Regional Ordinance have until February 1, 2016 to
adopt. The size of landscapes subject to MWELO has been lowered from 2500 sq. ft.
to 500 sq. ft. The size threshold applies to residential, commercial, industrial and
institutional projects that require a permit, plan check or design review. Additionally,
the maximum applied water allowance (MAWA) has been lowered from 70% of the
reference evapotranspiration (ETo) to 55% for residential landscape projects, and to
45% of ETo for non-residential projects. This water allowance reduces the landscape
area that can be planted with high water use plants such as cool season turf. For
typical residential projects, the reduction in the MAWA reduces the percentage of
landscape area that can be planted to high water use plants from 33% to 25%. In
typical non-residential landscapes, the reduction in MAWA limits the planting of high
water use plants to special landscape areas. The revised MWELO allows the
irrigation efficiency to be entered for each area of the landscape. The site-wide
irrigation efficiency of the previous ordinance (2010) was 0.71; for the purposes of
estimating total water use, the revised MWELO defines the irrigation efficiency (IE)
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of drip irrigation as 0.81 and overhead irrigation and other technologies must meet a
minimum IE of 0.75.
CalGreen requires that automatic irrigation system controllers for new landscaping
provided by a builder and installed at the time of final inspection must be weather- or
soil moisture-based controllers that automatically adjust irrigation in response to
changes in plant water needs as weather or soil conditions change.
The estimates of future water savings in Table 6 do not include potential landscape water savings
from implementation of MWELO or CalGreen standards because estimating these savings
required data that was not available to Cal Water at the time the 2015 UWMP plan was prepared.
Required data include existing and future landscape areas, plant materials, irrigation equipment,
enforcement of and compliance with the landscape design and irrigation equipment
requirements.
SSF District Population
In the 2015 UWMP, Cal Water updated the baseline period population estimates to incorporate
information from the 2010 US Census that was not available at the time the 2010 UWMP was
prepared. Updating resulted in a small change in the original population estimates.
Urban retail water suppliers must estimate their service area population consistent with DWR
requirements. For water suppliers whose boundaries correspond by 95 percent or more with a
city or census designated place, population estimates prepared by the Department of Finance
may be used. Where this is not the case, water suppliers may use the DWR Population Tool or
estimate their population using other methods, provided these methods comply with
Methodology 2 – Service Area Population – of DWR’s Methodologies for Calculating Baseline
and Compliance Urban Per Capita Water Use.
Cal Water uses a population estimation methodology based on overlaying Census Block data
from the 2000 and 2010 Censuses with the District’s service area. LandView 5 and MARPLOT
software are used with these data to estimate population per dwelling unit for 2000 and 2010.
The per dwelling unit population estimates are then combined with Cal Water data on number of
dwelling units served to estimate service area population for non-Census years.
Cal Water also estimated service area population using DWR’s Population Tool. The estimates
prepared using Cal Water’s methodology and DWR’s Population Tool differed by less than one
percent. A comparison of the estimates generated by the two approaches is provided in
Appendix I of the 2015 UWMP. Cal Water elected to use the population estimates produced by
its methodology in order to maintain consistency with population projections it has prepared in
other planning documents and reports.
SSF District Baseline Daily Per Capita Water Use
Baseline daily per capita water use is calculated by converting annual gross water use to gallons
per day and dividing by service area population. Daily per capita water use for each baseline
year and 2015 are summarized in Table 7.
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Table 7: SSF District Gallons Per Capita Per Day (GPCD)
Baseline Year Service Area
Population
Annual Gross
Water Use (AF)
Daily Per Capita
Water Use (GPCD)
10 to 15 Year Baseline GPCD
Year 1 1995 52,724 8,226 139
Year 2 1996 52,885 8,403 142
Year 3 1997 53,456 9,008 150
Year 4 1998 53,939 8,917 148
Year 5 1999 54,386 9,394 154
Year 6 2000 55,024 9,738 158
Year 7 2001 55,326 9,606 155
Year 8 2002 55,784 9,633 154
Year 9 2003 56,031 9,245 147
Year 10 2004 57,028 9,549 149
10-15 Year Average Baseline GPCD 150
5 Year Baseline GPCD
Baseline Year Service Area
Population
Annual Gross
Water Use (AF)
Daily Per Capita
Water Use (GPCD)
Year 1 2003 56,031 9,245 147
Year 2 2004 57,028 9,549 149
Year 3 2005 57,398 8,869 138
Year 4 2006 57,646 9,101 141
Year 5 2007 57,920 9,169 141
5 Year Average Baseline GPCD 143
2015 Compliance Year GPCD
2015 61,223 7,064 103
SSF District GPCD 2015 and 2020 Targets
Urban retail water suppliers may select from four GPCD target methods (CWC 10608.20).
Target Method 1: 20% reduction from 10-year baseline GPCD
Target Method 2: Water use efficiency performance standards
Target Method 3: 95% of Hydrologic Region Target
Target Method 4: Savings by water sector, DWR Method 4
Regardless of target method selected, the final target cannot exceed 95 percent of the 5-year
baseline period average GPCD (CWC 10608.22).
19
The South San Francisco District has selected Target Method 3, which sets the 2020 target to
either 95 percent of the San Francisco Bay Area Hydrologic Regional Target or 95 percent of the
5-year baseline average GPCD, whichever is less. This results in a 2020 target of 124 GPCD.
The 2015 interim target of 137 GPCD is the midpoint between the 10-year baseline average
GPCD and the 2020 target.
The District’s GPCD baselines and targets are summarized in Table 8.
Table 8: SSF District Baselines and Targets Summary
Baseline
Period Start Years End Years Average
GPCD
2015 Interim
Target
Confirmed
2020 Target
10-15 year 1995 2004 150 137 124
5 Year 2003 2007 143
2015 Compliance with Daily per Capita Water Use
Cal Water is not electing to make any adjustments to the District’s compliance daily per capita
water use in 2015. The South San Francisco District’s 2015 compliance daily per capita water
use is 103 gallons compared to its 2015 interim target of 137 gallons. The South San Francisco
District is in compliance with its 2015 interim target.
The low per capita water use in 2015 partially reflects the impacts of the Drought Emergency
Regulation adopted by the State Water Resources Control Board in May of 2015 (SWRCB
Resolution No. 2015-0032). Among other things, the Drought Emergency Regulation mandated
urban retail water suppliers reduce potable water use between June of 2015 and February of 2016
by percentage amounts specified by the State Water Resources Control Board. The South San
Francisco District was ordered to reduce potable water use by 8 percent over this period relative
to use over the same period in 2013.
However, the Drought Emergency Regulation does not explain all of the decline in per capita
water use, which has been trending downward since 2000 when it reached its zenith of 158
gallons per person per day. By 2014 this had fallen by 27 percent, to 115 GPCD. Between 2014
and the end of 2015, per capita water use had fallen an additional 11 percent, to 103 GPCD.
The following analysis indicates that the forecasted demand of the OPDP can be considered part
of the SSF District forecasted demand growth.
Actual demand for the SSF District in 2015 was 7,064 acre-feet/year (AFY) or 6.31 million
gallons per day (mgd). The forecasted demand for 2020 is 8,560 AF; so the forecasted increase
in average day demand for the 5-year period 2015 to 2020 is 1,496 AFY or 1.33 mgd. The total
OPDP forecasted increase in demand in 2020 is 219,051 gpd or 245.4 AFY. This represents
16.4% (245.4/1,496) of the projected increase in forecasted SSF District water demand for that
period.
20
Water demand for the SSF District in 2040 is 8,901 AFY or 7.95 mgd so the increase in average
day demand from 2020 to 2040 (20 year period) is 341 AFY or 0.304 mgd. After 2020, there is
no further increase in OPDP demand.
With respect to the 20 year forecast, OPDP demand is not a significant percentage in the
projected increase in District demand. For 2020, it leaves 83.6% of the projected increase for
other projects and general growth within the District. For 2040, it leaves 86.6% (1- 245.4/1,837)
for other projects and general growth.
Therefore, the WSA treats increases in water demand due to the OPDP as part of the SSF District
demand projection.
South San Francisco District Water Supply
Potable water supply for the District is a combination of purchased water and groundwater from
Cal Water owned wells. Water is purchased from the San Francisco Public Utilities Commission
(SFPUC). Cal Water’s annual allocation of SFPUC supply is shared among its three peninsula
districts: Bear Gulch, Mid-Peninsula, and South San Francisco. Annual supply from SFPUC to
its utility customers varies with precipitation and related hydrologic conditions. Water is
allocated among wholesale customers based on an existing agreement with the member agencies
of the Bay Area Water Supply and Conservation Agency (BAWSCA). The two stages of
allocation are discussed below. In addition, SFPUC supply to the South San Francisco District in
any given year varies slightly with availability of a local surface water supply in the Bear Gulch
District.
Cal Water, City San Bruno, City of Daly City and SFPUC have participated in an evaluation of
the Westside Groundwater Basin to determine the feasibility of entering into a conjunctive use
program. Preliminary results indicate that the South San Francisco District would have a
drought groundwater supply of 1,535 AFY, which is the District’s planned annual pumping
quantity.
Purchased SFPUC potable supply is delivered through a network of pipelines, tunnels and
treatment plants shown in Figure 7. This supply is predominantly from the Hetch Hetchy
reservoir, but also includes water produced from watersheds, reservoirs and treatment facilities in
Alameda and San Mateo Counties.
Purchased Water
The amount of imported water available to SFPUC’s retail and wholesale customers is
constrained by hydrology, physical facilities, and the institutional factors that allocate the water
supply of the Tuolumne River which is downstream of the Hetch Hetchy reservoir. Due to these
constraints, SFPUC is very dependent on reservoir storage of its water supplies. Local reservoirs
include: Crystal Springs Reservoir, San Andreas Reservoir, Pilarcitos Reservoir, Calaveras
Reservoir, and San Antonio Reservoir.
The Raker Act, which authorized the Hetch Hetchy project, prevents a privately owned utility
such as Cal Water from receiving water from the Hetch Hetchy system, but allows local sources
to be purchased. In addition, Cal Water is subject to the Water Supply Agreement between The
21
City and County of San Francisco and Wholesale Customers in Alameda County, San Mateo
County and Santa Clara County.
Supply Guarantee
In 1984, Cal Water and 29 other Bay Area water suppliers signed a Settlement Agreement and
Master Water Sales Contract (Master Contract) with San Francisco, supplemented by an
individual Water Supply Contract. These contracts provided for a 184 mgd (annual average
basis) Supply Assurance Allocation (SAA) to the SFPUC’s wholesale customers collectively.
This allocation was reached through negotiation in the early 1990s between the SFPUC and Bay
Area Water Users Association (BAWUA), the predecessor organization to BAWSCA.
In July 2009, Cal Water along with 29 other Bay Area water suppliers signed a Water Supply
Agreement (SFWSA) between The City and County of San Francisco and Wholesale Customers
in Alameda County, San Mateo County and Santa Clara County, which replaced the 1984
Settlement Agreement and Master Water Sales Contract (Master Contract). The SFWSA
continues the provision to provide a Supply Guarantee of 184 mgd, expressed on an annual
average basis to SFPUC wholesale customers collectively. SFPUC retail customers receive 81
mgd as a supply guarantee. Cal Water’s Individual Supply Guarantee (ISG) is 35.68 mgd or
39,967 acre feet per year.
Cal Water’s ISG for the three districts previously was 35.39 mgd (39,642 AFY). Acquisitions of
the Los Trancos County Water District in July 2005 allowed the transfer of its 0.11 mgd ISG to
Cal Water and the Skyline County Water District in 2009 allowed the transfer of its 0.181 mgd
ISG to Cal Water. These increased Cal Water’s total ISG for the three districts to 35.68 MGD
(39,967 AFY).
The SFPUC can meet the demands of its retail and wholesale customers in years of average and
above average precipitation. The SFWSA allows SFPUC to reduce water deliveries during
droughts, emergencies and for scheduled maintenance activities. SFPUC’s wholesale customers
through their collective organization, the Bay Area Water Supply and Conservation Agency
(BAWSCA) during 2010 negotiated the Drought Implementation Plan (DRIP), which replaces
the previously adopted Interim Water Shortage Allocation Plan. The SFWSA allocates the
required reduction of available water supply between San Francisco’s retail and wholesale
customers. The SFWSA established that during a called upon 20% drought reduction, collective
wholesale customers face up to a 28% reduction in their available supply, while SFPUC retail
customers face only a 2% reduction.
The DRIP aggregates the reduction applied to the wholesale customers and allocates it among
individual wholesale customers during water shortages of up to 20% of system-wide.
The DRIP uses an allocation process that takes into consideration the wholesale customer’s ISG
and the seasonal water use pattern of the wholesale customer’s service area. Communities that
use substantially more water in the summer will face a greater reduction in their allocated
drought supply. Health and safety adjustments were provided to increase the drought allocation
of several wholesale customers that have extremely low ISG values.
Much like the previously approved Interim Water Supply Allocation Plan, during a called upon
20% drought reduction because of the seasonal water use pattern of its customers and the recent
22
high demand that has reached or exceeded its ISG, Cal Water’s customers face a potential 33%
reduction in their available supply. By implementing conservation and seeking outside water
supplies that can be transferred into Cal Water’s service area, the magnitude of the potential
reduction can be reduced.
The SFWSA also calls for implementation of an Interim Supply Allocation (ISA) accompanied
by an Environmental Enhancement Fee. If the entire SFPUC service area exceeds the collective
supply guarantee of 264 mgd (81 mgd to SFPUC retail and 184 mgd to wholesale), then any
individual customer that exceeds their ISA will be assessed the yet to be determined
Environmental Enhancement Fee. Cal Water’s ISA has been set at its ISG of 35.68 mgd. This is
intended to be an incentive to implement conservation. In 2010, the collective SFPUC service
area used 214.4 mgd; the five year average use is 237.6 mgd.
In addition to hydrologic conditions, supply available to SFPUC’s retail and wholesale
customers also depends on the status of conveyance and treatment facilities and agreements that
allocate water supply.
While the Raker Act prohibits the SFPUC from selling water from the Hetch Hetchy project to
privately owned utilities, SFPUC makes available for purchase, water from its other sources to
privately owned utilities, i.e. Cal Water.
Cal Water’s purchased water supply from the SFPUC is subject to the Water Supply Agreement
between the City and County of San Francisco and Wholesale Customers, which was adopted in
July, 2009. As a means of addressing the aforementioned Raker Act exclusion the Water Supply
Agreement contains Article 9.02 A. which identifies Cal Water as an investor owned utility
company, and as such, has no claim to co-grantee status under the Act. In addition Article 9.02
B. states that:
The total quantity of water delivered by San Francisco to California Water Service
Company shall not in any calendar exceed 47,400 acre-feet, which is the estimated
average annual production of Local System Water. If San Francisco develops
additional Local System Water after the Effective Date, it may (1) increase the
maximum delivery amount stated herein; and (2) increase the Supply Assurance, but
not necessarily both. San Francisco has no obligation to deliver water to California
Water Service Company in excess of the maximum stated herein, except as such
maximum may be increased by San Francisco pursuant to this subsection. The
maximum annual quantity of Local System Water set forth in this subsection is
intended to be a limitation on the total quantity of water that may be allocated to
California Water Service Company, and is not an Individual Supply Guarantee for
purposes of Section 3.02. The maximum quantity of Local System Water set forth in
this subsection is subject to reduction in response to (1) changes in long-term
hydrology or (2) environmental water requirements that may be imposed by or
negotiated with state and federal resource agencies in order to comply with state or
federal law or to secure applicable permits for construction of Regional Water
System facilities. San Francisco shall notify California Water Service Company of
any anticipated reduction of the quantity of Local System Water set forth in this
subsection, along with an explanation of the basis for the reduction.
Short term changes in hydrologic conditions such as drought and supply emergencies are
governed by other provisions of the Water Supply Agreement including the two tiered allocation
23
plan adopted by the BAWSCA membership. This plan is described in Chapter 7 of the 2015
UWMP.
Water Supply Improvement Program (WSIP)
Figure 7 is a schematic showing the main projects that comprise the WSIP.
Figure 7: SFPUC Water System Improvement Program (WSIP) Projects
The WSIP goals and objectives are to improve the delivery reliability of the Regional Water
System, including water supply reliability and are summarized as follows:
Program Goal System Performance Objective
Water Supply –
meet customer
water needs in
non-drought and
drought periods
Meet average annual water demand of 265 mgd from
the SFPUC watersheds for retail and wholesale
customers during non-drought years for system demands
through 2018.
Meet dry-year delivery needs through 2018 while
limiting rationing to a maximum 20 percent system-
wide reduction in water service during extended
droughts.
Diversify water supply options during non-drought and
drought periods.
Improve use of new water sources and drought
management, including groundwater, recycled water,
conservation, and transfers.
The SFPUC historically has met customer demand in all types of water years. Typically, 85
percent of supply comes from the Tuolumne River from the Hetch Hetchy Reservoir and the
24
remaining 15 percent from local watersheds through the San Antonio, Calaveras, Crystal
Springs, Pilarcitos and San Andreas Reservoirs. The WSIP continues to use this mix of water
supply sources.
Water Supply – Dry Years
The WSIP includes the following water supply projects to meet dry year demands with no
greater than 20 percent system-wide rationing in any one year:
Calaveras Dam Replacement Project
Calaveras Dam is located near a seismically active fault zone and was determined
to be seismically vulnerable. To address this vulnerability, the SFPUC is
constructing a new dam of equal height downstream of the existing dam. The
Environmental Impact Report was certified by the San Francisco City Planning
Commission in 2011, and construction is now ongoing. Construction of the new
dam is slated for completion in 2018; the entire project should be completed in
2019.
Alameda Creek Recapture Project
The Alameda Creek Recapture Project will recapture the water system yield lost
due to instream flow releases at Calaveras Reservoir or bypassed around the
Alameda Creek Diversion Dam and return this yield to the RWS through facilities
in the Sunol Valley. Water that naturally infiltrates from Alameda Creek will be
recaptured into an existing quarry pond known as SMP (Surface Mining Permit)-
24 Pond F2. The project will be designed to allow the recaptured water to be
pumped to the Sunol Valley Water Treatment Plant or to San Antonio Reservoir.
Lower Crystal Springs Dam Improvements
The Lower Crystal Springs Dam Improvements were substantially completed in
November 2011. While the project has been completed, permitting issues for
reservoir operation have become significant. While the reservoir elevation was
lowered due to Division of Safety of Dams restrictions, the habitat for the
Fountain Thistle, an endangered plant, followed the lowered reservoir elevation.
Raising the reservoir elevation now requires that new plant populations be
restored incrementally before the reservoir elevation is raised. The result is that it
may be several years before the original reservoir elevation can be restored.
Regional Groundwater Storage and Recovery Project
The Groundwater Storage and Recovery Project is a strategic partnership between
SFPUC and three San Mateo County agencies: the California Water Service
Company (serving South San Francisco and Colma), the City of Daly City, and
the City of San Bruno. The project seeks to balance the management of
groundwater and surface water resources in a way that safeguards supplies during
times of drought. During years of normal or heavy rainfall, the project would
provide additional surface water to the partner agencies in San Mateo County,
allowing them to reduce the amount of groundwater that they pump from the
South Westside Groundwater Basin. Over time, the reduced pumping would allow
the aquifer to recharge and result in increased groundwater storage of up to 20
billion gallons.
25
The project’s Final Environmental Impact Report was certified in August 2014,
and the project also received Commission approval that month. The well station
construction contract Notice to Proceed was issued in April 2015, and
construction is expected to be completed in spring 2018.
2 mgd Dry-year Water Transfer
In 2012, the dry-year transfer was proposed between the Modesto Irrigation
District and the SFPUC. Negotiations were terminated because an agreement
could not be reached. Subsequently, the SFPUC is having ongoing discussions
with the Oakdale Irrigation District for a one-year transfer agreement with the
SFPUC for 2 mgd (2,240 acre-feet).
In order to achieve its target of meeting at least 80 percent of its customer demand during
droughts at 265 mgd, the SFPUC must successfully implement the dry-year water supply
projects included in the WSIP.
Furthermore, the permitting obligations for the Calaveras Dam Replacement Project and the
Lower Crystal Springs Dam Improvements include a combined commitment of 12.8 mgd for
instream flows on average. When this is reduced for an assumed Alameda Creek Recapture
Project recovery of 9.3 mgd, the net loss of water supply is 3.5 mgd. The SFPUC’s participation
in regional water supply reliability efforts, such as the Bay Area Regional Desalination Project
(BARDP), additional water transfers, and other projects is intended make up for this shortfall.
Groundwater
Groundwater has historically supplied ten to fifteen percent of SSF District water demand. It is
extracted from the Merced Formation of the Colma Creek Basin, a sub-basin of the Merced
Valley Groundwater Basin. Locally this basin is referred to as the Westside Basin.
Basin Description
The Westside Basin is the largest groundwater basin in the San Francisco Bay Hydrologic
Region. It is separated from the Lobos Basin to the north by a northwest trending bedrock ridge
through the northeastern part of Golden Gate Park. The San Bruno Mountains bound the basin on
the east. The San Andreas Fault and Pacific Ocean form its western boundary and its southern
limit is defined by bedrock high that separates it from the San Mateo Plain Groundwater Basin.
The basin opens to the Pacific Ocean on the northwest and San Francisco Bay on the southeast.
A detailed description of the basin is given in the DWR's Groundwater Bulletin 118 in Appendix
G.
DWR Bulletin 118 provides information on:
San Francisco Bay Hydrologic Region
Merced Valley (Westside) Basin
Santa Clara Sub-basin
Groundwater Basin Number: 2-35
Non-adjudicated Status of Basin
26
Groundwater Management
In June 2003, Cal Water entered into an agreement with the SFPUC to implement a pilot
conjunctive use program to test its practicality and potential impact on the regional groundwater
basin and Lake Merced recovery. This conjunctive use program is an in-lieu replenishment
operation where SFPUC delivers surplus surface water to Cal Water in exchange for a reduction
in groundwater use. The wells were taken offline while Cal Water participated in the pilot
program with the SFPUC. Cal Water resumed pumping groundwater in late 2008. During the
pilot program the static depth to groundwater decreased by approximately 35 feet.
The Regional Groundwater Storage and Recovery Project (GSR Project) is a joint effort between
SFPUC, Cal Water, and the Cities of Daly City and San Bruno to coordinate groundwater and
surface water management in the South Westside Basin. This project would increase water
supply reliability during dry years or emergency conditions. Cal Water, Daly City, and San
Bruno are BAWSCA members who use groundwater from the South Westside Basin to augment
their SFPUC supplies and are referred to as participating pumpers.
The SFPUC will install up to 16 new wells in the Westside Basin. There will be three
operational action cycles within the proposed Groundwater Storage and Recovery Program,
which are associated with the available SFPUC supply. When the SFPUC determines that there
is surplus supply available they can call for a “Put” cycle during which they will deliver some of
this surplus water to the program participants in-lieu of groundwater pumping by the
participating pumpers, thus putting or leaving the groundwater in storage in the basin.
During normal supply years, SFPUC will deliver the normal quantities of imported supply to the
participants who will also pump their Designated Quantity from the groundwater basin. Then
when imported supplies are short the participating pumpers will pump their Designated
Quantities and receive groundwater produced from the aforementioned SFPUC wells, and an
equally reduced quantity of imported water.
The SFPUC wells will only be operated to extract the previously stored or banked supply. The
expected groundwater storage gained from this reduced pumping is approximately 61,000 acre-
feet. With that amount of additional groundwater available in the basin, the agencies could pump
at rate of 7.2 mgd for a 7.5-year dry period.
Project facilities would include wells, disinfection, and distribution pipelines as needed, which
will be paid for by the SFPUC. SFPUC will pay all operation costs when the take cycle is
authorized. During non-drought emergencies the SFPUC wells would be available to the
participating pumpers to provide additional redundant supply capacity. However, the operational
cost for such an event would be paid for by the participating pumper.
In January 2015, the SFPUC awarded this $42.9 million construction contract to Ranger
Pipelines, Inc. Construction started in spring 2015 and completion is anticipated in spring 2018.
The District produces groundwater from an un-adjudicated basin; however, Cal Water has
voluntarily limited the annual production of groundwater from the Westside (Merced Valley)
Basin to 500 million gallons annually in response to shared concerns raised in a study prepared
for the City of Daly City that focused on local groundwater conditions.
27
In 1999 the Westside Basin Partners proposed a Groundwater Management Plan, but that plan
was not adopted by Cal Water and the other local jurisdictions. However, the partners
implemented many of the Basin Management Objectives from the Plan. In 2005, SFPUC
published a final draft of its North Westside Groundwater Basin Management Plan, which covers
the portion of the basin that is located in the City of San Francisco.
With SGMA passage in 2014 (see below for a detailed discussion of SGMA), a new effort is
underway to update the Groundwater Management Plan into a Groundwater Sustainability Plan
for the South Westside Basin. Cal Water is an active participant in this effort. A Letter of
Mutual Understanding has been signed in 2016 by all of the agencies.
Sustainable Groundwater Management Act
On September 16, 2014, Governor Brown signed into law Assembly Bill 1739, Senate Bill 1168,
and Senate Bill 1319 (AB-1739, SB-1168, and SB-1319). This three-bill legislative package is
known collectively as the Sustainable Groundwater Management Act (SGMA). SGMA was
amended in the later part of 2015 by Senate Bill 13, Senate Bill 226 and Assembly Bill 1390 to
provide clarity to the original law and guidance on groundwater adjudications. This new
legislation defines sustainable groundwater management as the “management and use of
groundwater in a manner that can be maintained during the planning and implementation horizon
without causing undesirable results” [Water Code § 10721(u)]. The legislation defines
“undesirable results” to be any of the following effects caused by groundwater conditions
occurring throughout the basin [Water Code § 10721(w) (1-6)]:
Chronic lowering of groundwater levels indicating a significant and unreasonable
depletion of supply;
Significant and unreasonable reduction of groundwater storage;
Significant and unreasonable seawater intrusion;
Significant and unreasonable degraded water quality;
Significant and unreasonable land subsidence;
Surface water depletions that have significant and unreasonable adverse impacts on
beneficial uses of the surface water.
The legislation provides for financial and enforcement tools to carry out effective local
sustainable groundwater management through formation of Groundwater Sustainability Agencies
(GSA's) consisting of local public agencies, water companies regulated by the CPUC and mutual
water companies. The legislation requires that GSA's within High and Medium Priority basins
under the California Statewide Groundwater Elevation Monitoring (CASGEM) program subject
to critical conditions of overdraft prepare and submit a Groundwater Sustainability Plan (GSP)
for the basin by January 31, 2020 [Water Code § 10720.7(a) (1)], and requires GSA's in all other
groundwater basins designated as High or Medium Priority basins to prepare and submit a GSP
by January 31, 2022 [Water Code § 10720.7 (a) (2)]. Following State approval, the basin would
thereafter be managed under the GSP. The legislation does not require adjudicated basins to
develop GSPs, but they are required to report their water use.
28
The key intended outcomes and benefits of SGMA are numerous, and include:
Advancement in understanding and knowledge of the State’s groundwater basins and
their issues and challenges;
Establishment of effective local governance to protect and manage groundwater
basins;
Management of regional water resources for regional self-sufficiency and drought
resilience;
Sustainable management of groundwater basins through the actions of GSA’s,
utilizing State assistance and intervention only when necessary;
All groundwater basins in California are operated to maintain adequate protection to
support the beneficial uses for the resource;
Surface water and groundwater are managed as “a Single Resource” to sustain their
interconnectivity, provide dry season base flow to interconnected streams, and
support and promote long-term aquatic ecosystem health and vitality;
A statewide framework for local groundwater management planning, including
development of sustainable groundwater management best management practices and
plans;
Development of comprehensive and uniform water budgets, groundwater models, and
engineering tools for effective management of groundwater basins;
Improved coordination between land use and groundwater planning;
Enforcement actions as needed by the SWRCB to achieve region-by-region
sustainable groundwater management in accordance with the 2014 legislation.
To assist in attaining the above outcomes, the California Department of Water Resources (DWR)
will provide GSA’s with the technical and financial assistance necessary to sustainably manage
their water resources. The benefits of these outcomes include:
A reliable, safe and sustainable water supply to protect communities, farms, and the
environment, and support a stable and growing economy;
Elimination of long-term groundwater overdraft, an increase in groundwater storage,
avoidance or minimization of subsidence, enhancement of water flows in stream
systems, and prevention of future groundwater quality degradation.
Cal Water’s groundwater basin policy is to work collaboratively with all stakeholders in the
basins where it operates and do what is best for managing the basin sustainably including sharing
of costs and benefits on an equitable basis. Cal Water recognizes and supports the goals,
objectives and intended outcomes of the SGMA and intends to take an active role in local and
state-wide management of groundwater resources over the next 5-25+ years.
29
The 2015 UWMP contains many of the elements required by SGMA and thus supports
implementation of SGMA and the basin GSP. SGMA’s specific requirements for groundwater
are addressed in:
Chapter 4: historic and future customer growth and water demand in the basin.
Chapter 6: historic and future water supplies in the basin and actions Cal Water will need
to take to develop additional water supplies to maintain supply reliability.
Chapter 6: water quality and necessary actions to protect and maintain water supplies.
Chapter 6: supplementing water supplies with recycled water.
Chapter 7: adequacy of the combined supplies to reliably meet customer demands under
normal, single-dry-year and multiple-dry-year conditions.
Westside Basin Storage
Cal Water routinely monitors the groundwater level of its wells in the Westside basin. Figure 6-2
shows the average ground water level for the South San Francisco District from 1990 to 2013.
The groundwater level increased about 35 feet between 2003 and 2007, as Cal Water, San Bruno,
and Daly City suspended groundwater pumping while participating in a pilot conjunctive use
program with SFPUC. Levels decreased beginning in 2010 due to drought conditions.
Figure 8: Average Ground Water Levels for District Wells
30
The May 2011, HydroFocus Westside Basin Model (version 3.1) indicates that the sustainable
municipal pumping rate is 6.9 mgd. Cal Water, Daly City, and San Bruno intend to coordinate
their respective pumping rates so that 6.9 mgd is not exceeded on an annual basis. Cal Water has
offered to limit its planned production of groundwater from the Westside Basin to 1.37 mgd
(1,535 AFY) which is consistent with current pumping capacity and historical pumping rates.
The amount of groundwater historically pumped is shown in Table 9.
Table 9: SSF District Groundwater Quantity Pumped (AF)
Groundwater
Type
Location or Basin
Name 2011 2012 2013 2014 2015
Alluvial Basin Merced Valley
(Westside) Basin 515 606 995 1,028 1,312
Total 515 606 995 1,028 1,312
Future Possible Water Supplies
Recycled Water
Currently, no municipal or industrial wastewater is processed for non-potable reuse in the SSF
District.
Use of recycled water has been and continues to be evaluated by the Cities of South San
Francisco and San Bruno, SFPUC, and Cal Water to reduce potable water demands on SFPUC
supply and groundwater pumping in the Westside Basin. Focus of use of recycled water has been
on non-potable uses – mainly landscape irrigation.
Daly City currently produces 2.77 mgd of recycled water, which is used for irrigation of the San
Francisco Golf Club, Olympic Club, Lake Merced Golf Club, Harding Park Golf Club, and
several city parks and medians. Daly City and the SFPUC are pursuing the Feasibility of
Expanded Tertiary Recycled Water Facilities Project, which will provide approximately 3 mgd
of additional recycled water irrigation supply to the cemeteries in the Town of Colma and other
parks and schoolyards. The goal of the project is to reduce reliance on the groundwater basin and
to create a local, drought-proof water supply. This expansion in currently in design; construction
is expected to occur in 2018-2019.
Cal Water examined the potential for recycled water use in its SSF District Water Supply and
Facilities Master Plan. It was further evaluated in its Integrated Long Term Water Supply Plan
for its three Peninsula Districts. These studies found a potential for 0.61 mgd of recycled water
demand in the SSF District. Because of the very high cost to treat and convey recycled water
from the South San Francisco Water Quality Control Plant (SSFWQCP), this supply is currently
not being pursued. Cal Water will reevaluate recycled water use in the future to determine
whether it has become more feasible.
The North San Mateo County Sanitation District (NSMCSD) treats wastewater from Cal Water’s
South San Francisco service area communities of Broadmoor and portions of Colma.
31
Communities also within the NSMCSD, but not in Cal Water’s service area include Westlake,
Westborough County Water District, Daly City, and the San Francisco County Jail. Municipal
wastewater is generated in the NSMCSD service area by residential, commercial, and limited
industrial sources. NSMCSD owns, operates and maintains its sewer system consisting of gravity
sewers and pumping stations.
South San Francisco and San Bruno own and operate SSFWQCP. Wastewater from Cal Water’s
South San Francisco service area communities of South San Francisco and Colma is treated at
the SSFWQCP. Wastewater from San Bruno and a small portion of Daly City is also treated at
the SSFWQCP, but these areas are not within Cal Water’s service area. The sewer system
includes gravity lines and force mains that combine both wastewater and storm water runoff.
The quantity of wastewater generated is proportional to the population and water use in the
service area. For 2015, it was estimated that 2,382 AFY of wastewater flows from Cal Water’s
South San Francisco District to the NSMCSD, and 3,500 AFY flows to the SSFWQCP for a total
of 5,882 AFY.
Wastewater Treatment in SSF District Area
Wastewater at the North San Mateo Wastewater Treatment Plant (NSMWTP) receives secondary
treatment. The NSMWTP cannot provide tertiary treatment. NSMWTP design treatment
capacity is 10.3 MGD average daily flow but currently receives 6.8 MGD from the North San
Mateo County Sanitation District service area. Effluent is discharged to an outfall at Thornton
Beach via pipeline. Secondary non-public contact treated water is currently recycled from this
plant for irrigation of landscaped medians in Westlake. Recycled water from the NSMWTP is
not available to the SSF District service area.
Wastewater from the South San Francisco Water Quality Control Plant (SSFWQCP) receives
secondary treatment with chlorination and de-chlorination before being discharged to the San
Francisco Bay. The SSFWQCP also provides de-chlorination for chlorinated effluent for
Burlingame, Millbrae, and San Francisco International Airport. The SSFWQCP has capacity to
treat 13 MGD average daily flow (instantaneous peak wet weather flow capacity of 30 mgd) and
currently receives 10 MGD from the SSFWQCP service area. The SSFWQCP does not provide
recycled water. An assessment of using recycled water from this plant was made by the firm
CDM in preparing the Cal Water’s Water Supply and Facilities Master Plan for the SSF District
and although it was concluded to not be feasible presently, it was recommended that recycling
should be re-evaluated in the future.
Potential for Water Recycled Water
South San Francisco has conducted studies to assess the feasibility of developing a recycled
water program and is continuing with further investigations to determine capital and operations
and maintenance costs associated with various stages of implementation of a water recycling
program as well as environmental, institutional, regulatory, and financial issues that must be
addressed.
NSMCWTP staff has worked on upgrading its treatment facilities to meet Title 22 requirements,
i.e., tertiary treatment. Some process improvements have been made. Planned uses for recycled
water include irrigation of three golf courses adjacent to the treatment plant and irrigation of
32
local median strips and athletic fields. However, theses golf courses currently use groundwater
for irrigation. The golf courses and median strips are not within Cal Water’s SSF district service
area. In addition, Cal Water’s service areas in Broadmoor and Colma are residential communities
with no current use for recycled water. It is hoped that potential customers will be served with
recycled water from the North San Mateo Wastewater Treatment Plant in the future, but none of
these potential customers are within Cal Water’s service area.
Current projected recycled water demand for Cal Water’s service area, which is served by
NSMWTP through 2040 is 0 acre-feet per year.
Cal Water will continue to participate in planning for future recycled water project(s) with South
San Francisco, San Bruno and SFPUC and consider supporting a joint feasibility study with Daly
City to investigate supplying recycled water to Colma cemeteries.
The SSFWQCP is near design capacity. Existing available space will be used to add facilities to
increase treatment capacity. Due to these conditions, SSFWQCP does not have plans to provide
recycled water in the near future.
Desalinated Water
Cal Water did an initial evaluation of developing desalinated water as a source of potable supply
in its 2009 WSFMP. It was studied in more detail in its 2011 Long Term Water Supply Plan
(LTWSP) for its three Peninsula Districts. Other agencies are also investigating a number of
potential regional and local desalination projects which could be developed to provide potable
water to the Cal Water Peninsula Districts.
The Bay Area Regional Desalination Project (BARDP) has identified one or two desalination
plants for producing potable water. Participating agencies would either directly receive
desalinated water or exchange other water among them. Participating agencies include Contra
Costa Water District (CCWD), East Bay Municipal Utility District (EBMUD), SFPUC, Santa
Clara Valley Water District (SCVWD), and Zone 7 Water Agency.
The BARDP evaluation process started in 2003 with the screening of 22 potential sites,
narrowing those down to three sites. The 2007 feasibility study screened and ranked
combinations of location, operation, and conveyance scenarios according to six issues:
environmental, permitting, institutional/legal, cost, public perception, and reliability. The highest
performing configuration was a 65 mgd facility in the City of Pittsburg, co-located with the
existing Mirant Power Plant. BARDP is currently conducting a Regional Reliability Study.
Potential Local Desalination Projects
The LTWSP indicated that a significant demand to supply gap can be anticipated during drought
conditions, which is summarized in Chapter 7 of the 2015 UWMP.
The LTWSP concluded that most viable alternatives to close this supply gap are through the
development of desalination facilities and/or water transfers. Because of the complexities and
high costs of developing these supplies, Cal Water plans to evaluate these two alternatives
further.
33
Desalination options involve developing reverse osmosis membrane treatment plants to remove
the salts from San Francisco Bay surface water or brackish groundwater beneath the bay. Based
on planning level cost estimates, brackish water desalination (with potential yields up to 5 mgd)
is the most attractive option for eliminating the supply gap. Use of surface bay water, while
more expensive, would provide greater treatment capacity and an opportunity for Cal Water to
supply desalinated water to nearby public water utilities which are supplied solely by the
SFPUC.
Implementing a desalination project will require 7 to 10 years. Several actions are necessary to
refine cost estimates including: determining sustainable brackish groundwater yield capacity,
determining the best well locations for extracting brackish water, confirming feasibility of brine
discharge locations, finding acceptable sites for treatment and finished water storage facilities,
and developing a pilot testing program. If a larger capacity desalination plant is warranted based
on interest from other water utilities, Cal Water will need to identify potential open water intake
sites, treatment and storage locations, and conveyance system facilities and estimate the
associated costs for implementing various alternatives.
The estimated cost of a more detailed feasibility study and preparing a preliminary engineering
report on the recommended desalination plant is approximately $3 million over a 4+ year period.
In order to proceed, Cal Water must obtain approval for this work from the CPUC, which
previously rejected Cal Water’s proposal.
Local desalination factors discussed in the LTWSP for the three peninsula districts included:
1. Location: varies from SSF to Redwood City. See Figure 10
2. Intakes: vertical wells for brackish groundwater, slant wells and open intake for seawater
3. Brine disposal: Joint use of a wastewater treatment plant outfall; new outfall; Cargill
brine line
4. Small capacity desalination plants: 1 – 10 mgd; subsurface intakes, easier to permit and
lower costs and risks
5. Large capacity desalination plant: 10 – 20 mgd: open seawater intake, harder to permit
and greater costs and risks
6. Likely Yields from different locations and intakes
7. Operations requirements and constraints
8. Environmental and permitting approval process, time requirements and costs
34
Water Transfers
The LTWSP examined several water transfer options as a means to augment existing supplies.
These include Delta transfers, pre-1914 water rights transfers, “green option” transfers, and
transfers of SFPUC water between BAWSCA agencies. Cal Water does not have any plans for
exchanges at this time.
The majority of the Delta transfers are between State Water Project (SWP) and Federal Central
Valley Project (CVP) contractors. Non SWP and CVP contractors have less access to transfers,
lower available supplies and more difficulty in accessing conveyance facilities for moving water
or for groundwater storage. In drought years, this results a low level of certainty on being able to
contract for and obtain additional water supplies.
Increasing reliability of long-term transfers generally requires use of groundwater storage or
banking. For SWP or CVP contractors and other parties, transfer of supplies from Central
Valley sources, groundwater storage has often depended on sites in Kern County. Storage and
conveyance of stored water adds to the purchase price of the water which under more extreme
drought conditions significantly increases.
Figure 10: Potential Desalination Plant Intakes and Brine Discharges
35
Even with contracts for transfer in place, storage would be required due to the seasonal
availability of Delta supplies. In addition, these supplies would still need to be transferred from
the Delta to the Peninsula Districts. This would most likely occur either through the South Bay
Aqueduct (SBA) or Santa Clara Valley Water District (SCVWD) transmission system from San
Luis Reservoir. Wheeling agreements would be required with DWR for transfers through the
SBA, and additional agreements with either Alameda County Water District (ACWD) or
SCVWD. That water would then need to be conveyed through other agency systems to Cal
Water District, or ACWD would transfer part of its SFPUC supply to the Cal Water.
Not including conveyance/wheeling charges, the price for Delta transfer supply depends on the
source, but currently is around $200/AF from the Sacramento Valley, and $400 to $900/AF for
San Joaquin transfers. During dry years these costs increase. These costs do not include
wheeling from the Delta to the Bay Area or then to the Peninsula Districts.
Pre-1914 Water Right Transfers
Another potential group of water transfers are pre-1914 water right supplies. These supplies
have higher priority than post-1914 and the majority of the SWP and CVP rights. As such, they
are not subject to the same environmental and institutional restrictions associated with the Delta
supplies. Pre-1914 rights are more reliable during droughts than other rights and have a higher
value and cost. One of the key issues is conveyance of that supply to the purchaser. This adds
complexity to the transfer arrangements, and increases the costs for wheeling of the supply.
Major issues associated with pre-1914 rights are long-term availability, especially during
droughts, and cost for purchase of the supply and cost and availability of infrastructure to
transfer supplies to Cal Water’s Peninsula Districts.
Transfers of “Green Option” Supplies
The conservation offset, or green option, is based on implementation of agricultural water use
efficiencies in the Lower Tuolumne River Watershed (LTRW) (i.e. Modesto Irrigation District
[MID] and Tuolumne Irrigation District [TID] service areas). The green option reduces
irrigation water requirements through implementation of agricultural water efficiency measures,
instead of fallowing land which can cause third-party impacts.
The Tuolumne river option has many advantages, including the high level of water quality. If
the project is a direct offset for releases to MID and TID this would be equivalent to Hetch
Hetchy supply. If this is water released from Don Pedro then additional treatment would be
required. In either case, conveyance would be through the SFPUC system, and would not
require other wheeling agreements outside of those with SFPUC.
Transfers between SFPUC wholesale customers
The water supply agreements with SFPUC allow the transfer of supply between wholesale
customers without penalty, or additional charges. However, the agreements do not allow carry
over from year to year if purchases were less than the interim supply agreement. This transfer
mechanism can be used if other wholesale customers have excess supply, either due to their
contract capacity, or if Cal Water were to fund other projects within these agencies that may free
up SFPUC supply for transfer.
Since it is likely water transfers can be implemented sooner than desalination, Cal Water is
considering this to be a short term solution to the identified supply gap.
36
Summary of Existing and Planned Sources of Water
Table 10 shows 2015 actual total supplies for the three peninsula districts.
Table 10: 2015 Peninsula Districts Actual Supplies
AF
SFPUC Purchased Water 28,404
Bear Gulch Surface water 437
SSF District Groundwater 1,312
Total 30,153
Table 11 shows the projected supply quantities to 2040. Cal Water’s SFPUC supply is shared
among all three Peninsula districts in order to provide operational flexibility to distribute the
supply as needed depending on the availability of local supplies and demands within each
district.
Table 11: Peninsula Districts Projected Water Supply (AF)
Year 2020 2025 2030 2035 2040
SFPUC Purchased Water 37,430 37,485 37,852 38,354 38,972
SSF District Groundwater 1,535 1,535 1,535 1,535 1,535
Bear Gulch Surface Water 1,260 1,260 1,260 1,260 1,260
Total 40,225 40,280 40,647 41,149 41,767
Purchased SFPUC supplies and local supplies (groundwater in the SSF District and surface water
in the Bear Gulch District) are discussed in the 2015 UWMP. Based on estimated demands for
all three districts, total supplies are anticipated to be sufficient to meet combined normal year
demands for all three districts through 2040. The supply amounts shown in Table 11 equal the
total projected demands for the three districts.
Climate Change Impacts to Supply
In 2016, Cal Water prepared an initial study of climate change impacts for some of its districts,
including the South San Francisco District.1 The districts included in the study account for 85%
of Cal Water’s total 2014 water production and reflect the diversity of Cal Water districts,
including geographic, hydrologic, and climatic conditions and primary and secondary supply
sources. The study was undertaken to gain a better understanding of the potential impacts of
climate change on the availability of water supplies. While impact projections are uncertain, they
are useful for estimating future supply changes and how they might be planned for in order to
ensure adequate and reliable supplies.
Changes in climate will affect the availability of local groundwater and surface water supplies, as
well as purchased imported supplies. The study addressed the impacts on each of these sources
1 California Water Service Company, Potential Climate Change Impacts on the Water Supplies of California Water
Service. January 2016.
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for each district. It relied on the best available projections of changes in climate (temperature and
precipitation) through the end of the century, and then used the climate projections to estimate
how surface water flows and groundwater recharge rates may change. Cal Water’s study
generally relied on studies and data provided by wholesale suppliers.
Climate change is primarily driven by increased concentrations of greenhouse gases (GHGs) in
the atmosphere. Future climate change is a function of the rate at which those concentrations
increase and how the atmosphere, oceans and land masses respond to increases in global
temperatures. While the scientific community overwhelmingly agrees that climate change has, is
and continues to occur, projections for localized areas with respect to impacts on temperature,
precipitation, runoff, groundwater and related hydrologic conditions are still subject to
significant uncertainty.
The projections of temperature and precipitation that underlie Cal Water’s study are based on 40
of the latest Global Circulation Models (GCMs) run as part of the Coupled Model Inter
comparison Project Phase 5 (CMIP5). This approach is termed an ensemble analysis, for which
the downscaled climate projections for any particular Cal Water Service District were based on
the median of the 40 downscaled GCM datasets. The GCMs used by the analysis are driven by
two GHG emission pathways that bound upper and lower estimates of GHG concentrations.
The climate change study combined the Mid-Peninsula, South San Francisco, and Bear Gulch
districts. Supply reductions due to climate change are projected to be between 6% and 15% for
these districts by the end of the century.
Climate change impacts will generally increase over time. Anticipated late 21st century impacts
are forecast to be higher in some districts than impacts at mid-century. Moreover, during the
period that climate change is forecast to reduce supplies, demands are forecast to increase.
Future potential Cal Water actions regarding climate change include:
Methodological improvements to reduce uncertainties
Acquiring better and more complete data;
Developing plans to address climate change reductions on supply
Water Supply Reliability Assessment
Using available historical information and projections of future water uses, regulatory and legal
constraints, and hydrological and environmental conditions, including climate change, Cal Water
has assessed the reliability of the SSF District’s water supplies.
Water Supply Agreement with SFPUC
In July 2009, the wholesale customers and San Francisco adopted the Water Supply Agreement
(WSASFPUC). Key features of that Agreement include:
Individual Supply Guarantee
San Francisco has a continuing commitment (Supply Assurance) to deliver 184 mgd to the 24
permanent wholesale customers collectively. San Jose and Santa Clara are not included in the
38
Supply Assurance commitment and each has temporary and interruptible water supply contracts
with San Francisco. The Supply Assurance is allocated among the 24 permanent wholesale
customers through Individual Supply Guarantees (ISG), which represent each wholesale
customer’s allocation of the 184 mgd Supply Assurance. Cal Water’s total ISG for the three
districts is 35.68 mgd.
2018 Interim Supply Limitation
As part of its adoption of the Water System Improvement Program (WSIP) in October 2008,
discussed separately herein, the SFPUC adopted a water supply limitation, the Interim Supply
Limitation (ISL), which limits sales from San Francisco Regional Water System (RWS)
watersheds to an average annual of 265 mgd through 2018.
All 26 wholesale customers and San Francisco are subject to the ISL. The wholesale customers’
collective allocation under the ISL is 184 mgd and the City of San Francisco’s is 81 mgd.
Although the wholesale customers did not agree to the ISL, the Water Supply Agreement
provides a framework for administering the ISL.
Interim Supply Allocations
The Interim Supply Allocations (ISAs) refer to San Francisco’s and each individual wholesale
customer’s share of the Interim Supply Limitation (ISL). On December 14, 2010, the SFPUC
established each agency’s ISA through 2018. In general, the SFPUC based the wholesale
customer allocations on the lesser of the projected fiscal year 2017-18 purchase projections or
Individual Supply Guarantees. The ISAs are effective only until December 31, 2018 and do not
affect the Supply Assurance or the Individual Supply Guarantees. Cal Water’s ISA for its three
peninsula districts is 35.68 mgd.
SFPUC’s wholesale customers do not concede the legality of the Commission’s establishment of
the ISAs and Environmental Enhancement Surcharge, and expressly retain the right to legally
challenge either or both, if imposed
Environmental Enhancement Surcharge
As an incentive to keep Regional Water System (RWS) deliveries below the ISL of 265 mgd, the
SFPUC adopted an Environmental Enhancement Surcharge for collective deliveries in excess of
the ISL effective at the beginning of fiscal year 2011-12. This volume-based surcharge would be
unilaterally imposed by the SFPUC on individual wholesale customers and San Francisco retail
customers, when an agency’s use exceeds their ISA and when sales of water to the wholesale
customers and San Francisco retail customers, collectively, exceeds the ISL of 265 mgd. Actual
charges would be determined based on each agency's respective amount(s) of excess use over
their ISA. To date, no Environmental Enhancement Surcharges have been levied.
2018 SFPUC Decisions
In the Water Supply Agreement, there are three decisions the SFPUC committed to making
before 2018 that will affect water supply development:
Whether or not to make the cities of San Jose and Santa Clara permanent customers,
Whether or not to supply the additional unmet supply needs of the wholesale
customers beyond 2018
39
Whether or not to increase the wholesale customer Supply Assurance above 184 mgd.
Additionally, there have been recent changes to in-stream flow requirements and customer
demand projections that will affect water supply planning beyond 2018. As a result, the SFPUC
has developed a Water Management Action Plan (Water MAP) to provide necessary information
to address the 2018 decisions and to begin developing a water supply program for the 2019 to
2035 planning horizon. The water supply program will enable the SFPUC to continue to meet its
commitments and responsibilities to wholesale and retail customers, consistent with the priorities
of the SFPUC.
The Water MAP was slated for SFPUC Commission discussion in 2016. The discussion resulting
from the questions described in the Water MAP will help guide the water supply planning
objectives through 2035. While the Water MAP is not a water supply program, it presents
pertinent information that will help develop the SFPUC’s future water supply planning program.
At this time, and for purposes of longer term planning, it is conservatively assumed that
deliveries from the Regional Water System to San Francisco’s wholesale customers will not be
in excess of 184 mgd.
Water Shortage Allocation Plan
The Water Shortage Allocation Plan (WSAP) allocates water from the Regional Water System
(RWS) to retail and wholesale customers during system-wide shortages of 20 percent or less (the
Tier One Plan). The WSAP has two components:
The Tier One Plan, which allocates water between San Francisco and the wholesale
customers collectively; and
The Tier Two Plan, which allocates the collective wholesale customer share among
the wholesale customers
Tier One Drought Allocation
The Tier One Plan allocates water between San Francisco and the wholesale customers
collectively based on the level of shortage. It is summarized in Table 12.
Table 12: SFPUC Tier One Drought Allocation
Level of System-Wide
Reduction in Water Use
Required
Share of Available Water
SFPUC Share Wholesale Customers Share
5% or less
6% through 10%
11% through 15%
16% through 20%
35.5%
36.0%
37.0%
37.5%
64.5%
64.0%
63.0%
62.5%
The Tier One Plan allows for voluntary transfers of shortage allocations between the SFPUC and
any wholesale customer and between wholesale customers. In addition, water “banked” by a
wholesale customer, through reductions in use greater than required, may be transferred.
The Tier One Plan will expire at the end of the term of the WSA in 2034, unless mutually
extended by San Francisco and the wholesale customers.
40
The Tier One Plan applies only when the SFPUC determines that a system-wide water shortage
exists and issues a declaration of a water shortage emergency under California Water Code
Section 350. Separate from a declaration of a water shortage emergency, SFPUC may opt to
request voluntary cutbacks from San Francisco and the wholesale customers to achieve necessary
water use reductions during drought periods. During the most recent drought, SFPUC requested,
but did not mandate, a 10 percent system-wide reduction starting January 2014. The SFPUC did
not declare a water shortage emergency and implement the Tier One Plan because its customers
exceeded the 10 percent voluntary system-wide reduction in conjunction with the state-wide
mandatory reductions.
Tier Two Drought Allocation
The wholesale customers have negotiated and adopted the Tier Two Plan, the second component
of the WSAP, which allocates the collective wholesale customer share among each of the 26
wholesale customers. This Tier Two allocation is based on a formula that takes into account
multiple factors for each wholesale customer including:
Individual Supply Guarantee;
Seasonal use of all available water supplies; and
Residential per capita use.
The water made available to the wholesale customers collectively will be allocated among them
in proportion to each wholesale customer’s Allocation Basis, expressed in millions of gallons per
day (mgd), which in turn is the weighted average of two components. The first component is the
wholesale customer’s Individual Supply Guarantee, as stated in the WSA, and is fixed. The
second component, the Base/Seasonal Component, is variable and is calculated using the
monthly water use for three consecutive years prior to the onset of the drought for each of the
wholesale customers for all available water supplies. The second component is accorded twice
the weight of the first, fixed component in calculating the Allocation Basis. Minor adjustments
to the Allocation Basis are then made to ensure a minimum cutback level, a maximum cutback
level, and a sufficient supply for certain wholesale customers.
The Allocation Basis is used in a fraction, as numerator, over the sum of all wholesale
customers’ Allocation Bases to determine each wholesale customer’s Allocation Factor. The
final shortage allocation for each wholesale customer is determined by multiplying the amount of
water available to the wholesale customers’ collectively under the Tier One Plan, by the
wholesale customer’s Allocation Factor.
The Tier Two Plan requires that the Allocation Factors be calculated by BAWSCA each year in
preparation for a potential water shortage emergency. As the wholesale customers change their
water use characteristics (e.g., increases or decreases in SFPUC purchases and use of other water
sources, changes in monthly water use patterns, or changes in residential per capita water use),
the Allocation Factor for each wholesale customer will also change. However, for long-term
planning purposes, each wholesale customer shall use as its Allocation Factor, the value
identified in the Tier Two Plan when adopted. The current Tier Two Plan will expire in 2018
unless extended by the wholesale customers.
The Water Shortage Allocation Plan was not as effective in the recent drought as intended.
Consequently, modification of plan is planned so that it better matches with proposed
permanent state requirements.
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Reliability by Type of Year
SFPUC modeled wholesale supply availability using its historic record. Unconstrained wholesale
supply is 184 mgd. SFPUC defines a single dry year as the first year that storage levels decrease
to the point that system-wide water supply rationing is necessary. In 2015, wholesale supply was
estimated to be 152.6 mgd. SFPUC’s multiple dry year cycle begins with one dry year followed
by two additional dry years in which storage levels drop further, such as the 1987-88 through
1989-90 sequence. The wholesale supply in the second and third years is estimated at 129.2 mgd.
For a single dry year, Cal Water assumes SFPUC supply to be 129.2 mgd with the 2015 water
conveyance infrastructure and 132.5 mgd in subsequent years resulting from infrastructure
improvements. For three consecutive dry years, Cal Water assumes wholesale supply is 129.2
mgd to 2019 and 132.5 mgd in 2020 and thereafter as a result of completion of SFPUC
infrastructure improvements.
According to BAWSCA, the Tier 2 allocation of the 129.2 mgd would result in Cal Water being
supplied 27.81 mgd through 2019 and 28.52 mgd in 2020 and thereafter.
Cal Water chose 1990 as its single dry year. This is the driest of years in Cal Water’s historical
precipitation record. The three year dry period is 1990, 1991 and 1992.
Table 13 summarizes Cal Water’s expected dry years SFPUC supplies for its three peninsula
districts.
Table 13: Cal Water Dry Years SFPUC Supplies
Year Type Base Year
Available SFPUC Supplies
AF
Single-Dry Year 1990 33,836
Multiple-Dry Years 1st Year 1990 33,836
Multiple-Dry Years 2nd Year 1991 34,223
Multiple-Dry Years 3rd Year 1992 34,223
Normal Water Year
Table 14 shows the projected supply and demand totals for the 3 districts for a normal year. In
normal years the full ISG of 35.68 MGD (39,967 AF) is available. Table 14 shows the total of
SFPUC, SSF District groundwater and the Bear Gulch District surface supplies meets the
combined demands of the three districts.
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Table 14: 3 Districts - Normal Year Supply and Demand Comparison (AF)
2020 2025 2030 2035 2040
Supply totals 40,225 40,280 40,647 41,149 41,767
Demand totals 40,225 40,280 40,647 41,149 41,767
Difference 0 0 0 0 0
Single Dry Year
Table 15 shows the projected supply and demand totals for the 3 districts for a single dry year.
Based on historical records, supply from the Bear Gulch Reservoir provides 351 AF in single dry
year. The SSF District’s groundwater supply of 1,535 AFY will be unaffected by a single dry
year. SFPUC supply is 31,950 AF. Projected shortages exceed 20% by the end of the planning
period.
Table 15: 3 Districts - Single Dry Year Supply and Demand Comparison (AF)
2020 2025 2030 2035 2040 (Opt)
Supply totals 33,836 33,836 33,836 33,836 33,836
Demand totals 41,984 42,041 42,425 42,947 43,591
Difference (8,148) (8,205) (8,589) (9,111) (9,755)
Percent Shortage 19% 20% 20% 21% 22%
Multiple Dry Years (3)
Table 16 shows the projected supply and demand for the 3 districts for 3 consecutive dry years.
Based on historical records, supply from the Bear Gulch Reservoir provides an average of 609
AFY in 3 successive dry years. The first year is assumed to be 351 AF - the same as the single-
dry year of 1990. The subsequent two years based on records are expected to provide 738 AFY.
The SSF District’s normal groundwater supply of 1,535 AFY is expected to unaffected in dry
years 2 and 3. Total supplies in Table 15 include these quantities and a SFPUC supply of 31,950
AF. Shortages up to 22% in the first year are followed by projected second and third year
shortages between 14% and 19%.
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Table 16: Three Consecutive Dry Years Supply and Demand Comparison
2020 2025 2030 2035 2040
First year Supply
totals 33,836 33,836 33,836 33,836 33,836
Demand
totals 41,984 42,041 42,425 42,947 43,591
Difference (8,148) (8,205) (8,589) (9,111) (9,755)
% Shortage 19% 20% 20% 21% 22%
Second year Supply
totals 34,223 34,223 34,223 34,223 34,223
Demand
totals 40,764 40,819 41,192 41,700 42,327
Difference (6,541) (6,596) (6,969) (7,477) (8,104)
% Shortage 16% 16% 17% 18% 19%
Third year Supply
totals 34,223 34,223 34,223 34,223 34,223
Demand
totals 39,758 39,812 40,176 40,671 41,283
Difference (5,535) (5,589) (5,953) (6,448) (7,060)
% Shortage 14% 14% 15% 16% 17%
In summary, the District has a sufficient supply under normal hydrological conditions. However,
during one-year or multi-year periods, shortfalls up to 22% are projected. Under such conditions,
Cal Water will implement its Water Shortage Contingency Plan, as described in Chapter 8 of the
SSF UWMP.
In the 2012 – 2015 drought, District customers were requested to reduce their demand by 8% as
specified by the State Board Resources Control Board. The District achieved 20% reductions
based on June 2015 to March 2016 data. Cal Water continues to work on plans to increase its
water supply sources for this District and for the other two peninsula districts (Mid-Peninsula
and Bear Gulch).
Regional Supply Reliability
Cal Water coordinates with other water agencies in the region to make best use of regional water
supplies. This includes SFPUC, City of San Carlos, City of San Mateo, Silicon Valley Clean
Water, and other public and private entities in the Bay area.
Cal Water’s continued implementation of its conservation programs in all three peninsula
districts has and is expected to continue to reduce per-capita usage and therefore total demands.
To ensure that its mix of programs is cost-effective manner possible, Cal Water routinely
conducts comprehensive reviews of its conservation program. This is done in tandem with its
updating its UWMPs for each district every 5 years. The Conservation Master Plan is the basis
44
for the implementation of measures and policies and expected resultant water savings. Demand
Management Measures (DMMs) are presented in Chapter 9 of the UWMP. A copy of the
Conservation Master Plan is provided in Appendix L of the UWMP. Cal Water also monitors
and supports the goals of the Bay Area Integrated Regional Water Management Plan (IRWMP).
These goals include:
Promote environmental, economic and social sustainability
Improve water supply reliability and quality
Protect and improve watershed health and function and Bay water quality
Improve regional flood management
Water Supply Projects
Cal Water will continue its annual main replacement program to upgrade and improve the
distribution system of the SSF District. Storage facilities and new booster pumps are added as
needed to meet the average day and maximum day requirements. Future capital expenditures are
planned for drilling and developing new wells to replace aging wells currently in operation,
which will increase system reliability and allow Cal Water to pump its full share of sustainable
extracted groundwater from the Westside basin. Cal Water’s SSF District Water Supply and
Facilities Master Plan will be updated in the next two years.
Water Demand Management
As previously discussed, effective water conservation reduces water demand which reduces
water supply needs. Cal Water’s existing conservation programs, including expanded SB7 driven
programs have demonstrated that Cal Water can achieve over 22% reduction in demand – the
worst case scenario for supply shortfall during a dry year in 2040.
SSF District total demand in 2009 was 8,502 AFY. Even with an increase of 120 services
between 2009 and 2016, demand decreased to 6,570 AFY or by 22.7% in 2016.
Continued conservation programs will enable Cal Water to meet its supply obligations for
normal, single dry year and multiple dry year conditions.
During severe drought periods such as occurred during the 2012- 2015 period, there were no
shortfalls in supply that necessitated implementation of more extreme demand reduction
measures.
Should periods of more severe water supply shortages occur, Cal Water has in place plans and
measures for further reducing customer water demand beyond 22%. This includes if necessary
mandatory reductions, rationing, and penalties.
As shown in Table 17, Cal Water has a four-stage water demand reduction plan comprised of
voluntary and mandatory stages. Approval from the CPUC must be obtained prior to
implementation of mandatory restrictions.
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Table 17: SSF District Water Demand Reduction Plan
Supply Shortage Stage Demand Reduction
Goal Type of Program
Minimum
5 - 10% Stage 1 10% reduction Voluntary
Moderate
10 - 20% Stage 2 20% reduction Voluntary or
Mandatory*
Severe
20 - 35% Stage 3 35% reduction Mandatory*
Critical
35 - 50% Stage 4 50% reduction Mandatory*
* Mandatory = Allocations
The following summarizes the actions to be taken during periods when demand reduction is
required:
Stage 1
Public information campaign consisting of distribution of literature, speaking
engagements, monthly bill inserts, and conservation messages printed in local
newspapers (ongoing)
Educational programs in area schools (ongoing)
Stage 2
More aggressive public information and education programs
Requests to consumers to reduce voluntarily water use by 10 to 20 percent or mandatory
reductions will be implemented
Prior to implementation of mandatory reductions, obtain approval from CPUC
Lobby for passage of drought ordinances by appropriate governmental agencies
Stage 3
Implement mandatory reductions after receiving approval from CPUC
Maintain rigorous public information campaign explaining water shortage conditions.
Water use restrictions go into effect; prohibited uses explicitly defined
Limiting landscape irrigation by restricting hours of the day and or days of the week
during which water for irrigation can be used
Monitor production weekly for compliance with necessary reductions
Installation of flow restrictors on the service lines of customers who consistently violate
water use restrictions
Stage 4
All of steps taken in prior stages intensified.
Discontinuance of water service for customers consistently violating water use
restrictions
Monitor production daily for compliance with necessary reductions
More restrictive conditions or a prohibition of landscape irrigation
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Section 357 of the Water Code requires that suppliers that are subject to regulation by the CPUC
shall secure its approval before imposing water consumption regulations and restrictions required
by water shortages.
Design, Construction and Operation of OPDP Water Supply Facilities
As planning and design proceed further, Cal Water anticipates working closely with the
developer, its engineer, the City of South San Francisco, California Department of Drinking
Water (DDW) and any other agencies that may be involved with the approval of required water
supply facilities.
Cal Water will prepare design drawings and specifications for compliance with state and Cal
Water’s standards with respect to pipe sizes, valves, materials, etc. and connection to its existing
system.
Cal Water’s SSF District, supported by its engineering, water quality and customer service staff
in San Jose, will be responsible for providing ongoing local operations and maintenance services
of the water system.
SB 610 Section 10910 Paragraph (d)(2) requires identification of existing water supply
entitlements, water rights, or water service contracts held by the public water system shall be
demonstrated by providing information related to all of the following:
(A) Written contracts or proof of entitlement to an identified water supply.
Proof of entitlement to use of the wells cited as a major supply source to the District is
demonstrated by Cal Water’s ownership of the property and the wells and its legal right
to use the underlying percolated waters.
Proof of entitlement to the use of SFPUC treated water are provided in the contracts cited
in this document between Cal Water and SFPUC and are available for review.
(B) Copies of a capital outlay program for financing the delivery of a water supply system
that has been adopted by the public water system.
Capital costs for design and construction of the water distribution system within the
development site are the responsibility of the developer.
Cal Water’s SSF District capital improvement program is separate from and does not
include any of the costs associated with the design and construction of the water system
for or within the OPDP area. However, upon legal transfer of the completed water system
within the development site to Cal Water by the developer, the water system will be
incorporated into Cal Water’s capital improvement and maintenance programs.
The SSF District 2009 Water Supply and Facilities Master Plan provides specific
recommendations for water system facility and capital improvements to the year 2030.
Cal Water plans to update this plan in the 2017- 2018 period.
Federal, state, and local permits for construction of necessary infrastructure associated
with delivering the water supply.
47
For any distribution system improvements, the developer will be required to obtain the
necessary building permits from the City of South San Francisco.
Cal Water is highly experienced in preparing applications and obtaining the necessary permits
that are needed in order to proceed with design, construction, startup and operation of water
distribution facilities. Cal Water is familiar with approvals it must obtain from the City of South
San Francisco and DDW
Summary of Supply and Demand Reliability Analysis
Normal Hydrologic Year
For all three Cal Water peninsula districts served by SFPUC, the combination of existing local
and purchased supplies are adequate to meet forecasted demands for the OPDP and those
associated with existing Cal Water customers for the next 20+ years
Single Dry Year
For a single dry year supplies may be less than normal projected demands if SFPUC supplies are
reduced, which historically has not occurred. Generally, Cal Water does not expect a reduced
supply, but if SFPUC does reduce its supplies, Cal Water will implement additional demand
reduction measures. The amount of groundwater that will be pumped will not be reduced. During
a single dry year treated surface water from the Bear Gulch Reservoir in the Bear Gulch District
will most likely decrease. While a single dry year may trigger increased water demand reduction
measures, demand has not been reduced to reflect those measures. Depending on when in the
next 20+ years another single dry year occurs, additional supply sources (water transfers and
desalination) may have been developed and be available to offset any reductions in existing
sources.
Three Consecutive Dry Years
During a 3 years dry period, supplies will be less than normal demand by a range from 14% to
22% in 2040 depending on which dry year it is and the projected future date. Again, Cal Water
will assess any supply reduction notifications from SFPUC, the availability of water from its
treated surface source in Bear Gulch District and whether it can continue to pump groundwater at
its historically normal rate. Westside Basin groundwater supplies would likely continue to be
pumped at current rates although that would result in a reduction in basin storage and a lowering
of groundwater levels. During years of above normal rainfall, it is expected that groundwater
storage would increase as has been the case in past decades.
Depending on when in the next 20+ years successive dry years occur, additional supply sources
(water transfers and desalination) may have been developed and be available to offset any
reductions in existing supply sources. If not, Cal Water will determine what additional demand
reduction measures will be needed to reduce demand to match available supplies. As previously
noted, Cal Water exceeded its goal of reducing demands during the most recent (2010- 2015)
severe drought.
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If in the first dry year, demand reduction responses do not appear to be sufficient, Cal Water will
implement additional conservation measures in the second and third years. This is expected to
result in an adequate supply for all three Cal Water peninsula districts from 2020 to 2040.
Conclusions
Based on:
1. Current Westside Basin groundwater supplies and Cal Water’s current and projected
groundwater production rates from its active wells,
2. Generally adequate long-term normal hydrologic supplies provided by the SFPUC, but
recent significant proposed reductions in supply during multiple dry year periods,
3. An effective demand reduction program to meet requirements of state laws,
4. Future Cal Water plans to develop additional supply sources including
transfers/exchanges of supplies from outside the peninsula area and development of local
desalination facilities,
5. The prospect of longer term additional local supplies being obtained from SFPUC’s
proposed conjunctive use program for the Westside Basin,
6. Possible recycled water projects being developed collaboratively among local wastewater
and water utilities in the SSF District area,
7. Cal Water’s ability to achieve additional drought driven reductions in demand (15% to
26%) during multiple dry year periods through its established in-place water programs,
8. Historical performance which demonstrates Cal Water’s ability to both increase supply
sources and effectively achieve demand reductions if required,
Cal Water’s concludes that for the next 20 years, its SSF District will be able to provide
adequate water supplies to meet existing and projected customer demands, which includes full
development of the proposed Oyster Point Development Project for normal, single dry year and
multiple dry year conditions.
Cal Water will ensure that the required water facilities are designed consistent with the proposed
development plan and will coordinate with the developer, its engineer, the City of South San
Francisco, and the California Division of Drinking Water in the design, construction and
operation of the proposed water distribution system.
End of WSA Document
49
References
1. California Water Service 2015 Urban Water Management Plan South San Francisco
District (Adopted June 2016) 341 North Delaware Ave San Mateo, California 94401
2. California Water Service Company 2010 Urban Water Management Plan South San
Francisco District (Adopted June 2011) 341 North Delaware Ave San Mateo, California
94401
3. California Water Service Company, Long Term Water Supply Plan for Three Peninsula
Districts (2011), 1720 North First St, San Jose, CA 95112
4. California Water Service Company South San Francisco District Water Supply and
Facilities Plan 2009, 1720 North First St, San Jose, CA 95112
5. California Water Service Supply Water Demand and Supply Data 2010 – 2016 (May –
June 2017), 1720 North First St, San Jose, CA 95112
6. California Water Service Company, Potential Climate Change Impacts on the Water
Supplies of California Water Service January 2016, 1720 North First St, San Jose, CA
95112
7. City of South San Francisco Economic and Development Department (Billy Gross,
Senior Planner): Background Information and Data on Oyster Point Development Project
(May 2017)
8. Wilsey Ham – Engineering, Surveying and Planning, Amy Dunning, Supervising
Engineer, San Mateo, CA: Updated information on development facilities (May 2017)