HomeMy WebLinkAboutR6180A - WATER MANAGEMENT ELEMENT OF THE GENERAL PLAN AdoptionRESOLUTION NO. 6180A (1987 Series)
A RESOLUTION OF THE COUNCIL OF THE CITY OF SAN LUIS OBISPO
ADOPTING THE WATER MANAGEMENT ELEMENT OF THE GENERAL PLAN
WHEREAS, the Planning Commission and the City Council have held public hearings on
this element in accordance with the California Government Code; and
WHEREAS, this element comes to the council upon the recommendation of the Planning
Commission; and
WHEREAS, the potential environmental impacts of the element have been evaluated in
accordance with the California Environmental Quality Act and the city Environmental
Guidelines and an environmental impact report has been certified.
NOW, THEREFORE, the council resolves as follows:
SECTION 1. Finding.
The Water Management Element is consistent with other elements of the general plan.
SECTION 2. Adoption.
The Water Management Element is hereby adopted as a section of the general plan. The
element consists of the draft Water Management Element(dated December 1986), with
revisions indicated in the attached Exhibit A.
2. The Community Development Director shall cause the adopted document to be published
and distributed to appropriate city officials, public agencies, and libraries, and to
be available to the public at a cost not to exceed the city's expense for
reproduction.
R 6180A
Resolution No. 6.18.OA (1987 Series)
Page 2
I' J
On motion of Councilman :Grif: fin;_.=-seconded !by _Councilman° Settle,-- and on- the
'following roll call vote:
AYES: Councilmembers Giiffinj= Set -tle; Douey =Rappa and Mayor Dunin
NOES: none
ABSENT: none
the foregoing resolution was passed and adopted this . 24th day of . February .. , 1987.
Mayor Ron Dunin
.ty Clerk Pamela Vo e
APPROVED:
City Administrative Vf ficer
............ .. ..........
r
City Attor ley
Community Development Director
EXHIBIT A
Revisions to draft Water Management Element for adoption
Page Proposed Chanee
Revise paragraph 5 to read: "Immediately following adoption of this Water
Management Element, the city will refine the Water Management Plan for
consistency with the element and adopt it as a guide for funding and carrying
out .specific conservation, water- supply, and treatment, storage, and
distribution projects. The City Council would decide to actually proceed with
projects or changes to operations or water rates during public hearings on city
budgets, capital facility programs, or other specific agenda items."
3 Add to the discussion of climate and rainfall: "The reliable yield of the
city's reservoirs is determined by the driest six -year period on record, which
was 1945 to 1951. During this interval, annual rainfall averaged 16 inches,
about 73 percent of the 115 -year annual average."
4 Include 1986 rainfall data in Figure 1.
6 Correct the note to Figure 3 to read "This chart shows ... about 91 percent of
all.." and "The remaining nine percent of total treated water is accounted for
by ..., water system leaks, and inaccurate meters."
7 Revise Figure 4 to show actual 1986 water use.
9 Revise the last sentence of paragraph #5 to read: "The Whale Rock Commission
has sold surplus water to Cuesta College (about 100 acre -feet per year).
12 Revise the last paragraph to read: "In 1986 -87, the city water system budget
was $2.76 million. In that year, the average cost for an acre -foot of water was
about $340, or about $68 per person, including all operating, debt- service, and
administrative costs."
13 Revise first paragraph to read: "The supplemental water projects ... in 1986.
Dividing this cost by the additional population which would be accommodated by
the increased water supply results in about $1,300 per person. Dividing this
cost by the total future population results in about $360 per,person. These
figures provide a rough comparison of charging water - project costs to new
development or to all customers, though they do not imply specific water rate
changes or development fees. These figures may change significantly::."
16 Add to the groundwater discussion: "In 1942, the last full year of production,
city wells yielded 1,164 acre -feet. Historical yield may not be an accurate
basis for estimating current potential yields, which may be lower or higher.
The historical yield may not indicate quantities available during a severe
drought, when all sources would be most strained. Also, groundwater would have
to meet today's quality standards.
n
Page Pr000sed change
17 Add a new item:
"Preventing siltation
If the city prevented silt. from reducing the yields of existing reservoirs, the
need for additional water could be reduced accordingly. Siltation can be
prevented by providing erosion - control planting and by minimizing disturbances
to natural vegetation (due to fire, road building, or excessive livestock
grazing). Also, small dams can be built on tributary streams to catch sediment
before it enters the reservoir. The silt must then be removed from the catch
basins. Silt can be dredged from reservoirs. Preliminary studies indicate that
silt dams and dredging are less cost - effective than developing some of the new
sources which have been considered."
19 Revise policy 1.1 to read: "The current ... of the city. The city shall
provide... limits."
19 Revise policy 1.2 to read: "The urban reserve line (the outer limit to urban
development) includes areas which the city may annex in the future. Water
service adequate for potential uses allowed by the Land Use Element (including
hillside planning provisions) shall be provided for all areas within the urban
reserve line."
19 Revise policy 1.4 to read: "The city will not provide water service to areas
outside the urban reserve line, except as it may decide to share Whale Rock
water supplies with Cuesta College. (The city should, however, ...and other
cities.)"
20 Revise policy 1.7 to read:
"The city's water ... systems must be able to support... Element.
"The city will pursue sources of supplemental water to serve the land use and
rates of growth outlined in the general plan, with a reasonable margin for error
in projections. The city shall, by separate agreement, provide Cuesta College
with an annual supply of water consistent with the availability of existing
sources."
21 Revise policy 1.8 to read:
"The city will not annex an area unless the safe annual yield of available
citywide water supplies... The only exceptions to this policy area:
A. Areas which have prior agreements for water service;
B. Minor infill parcels within such areas, as provided in policy 1.3;
C. Areas which provide their own water, as described in policy 3.4.
Page Proposed change
21 Revise the timeframe of program 1.2 to read: "Following adoption of the Land
Use Element update."
22 Revise policy 2.3 to read: "The city should not allow ... water. Total city
water use (including Cuesta College use of Whale Rock Water) should not exceed
the total safe yield by more than 13 percent: When total water use exceeds safe
yield by ten to 13 percent, the full safe yield of any supplemental sources
obtained will be allocated to reducing the amount by which current use exceeds
safe yield. When total water use exceeds safe yield by less than ten percent,
one -half the safe yield of any supplemental supplies obtained will be allocated
to support additional development and one -half will be allocated to reducing the
amount by which current use exceeds safe yield.
"In long -term planning for supplemental water supplies, projected water use
should not exceed safe yield"
22 Revise policy 2.4 to read: "When building entitlements must be limited to avoid
excessive increases in water use, water supply should be allocated.."
24 Revise program 2.4 to read: "To prevent development from jeopardizing water
service when supplies are not adequate, the city will adopt an ordinance which
controls increases in water use by limiting new development and changes in land
use. As outlined in policies 2.3 and 2.4 (Figure 7)i depending on the severity
of the water shortage, the ordinance could prevent construction or changes in
building occupancy which would increase water use. Also, as the maximum
acceptable level of risk in providing adequate water for the community is
reached, the ordinance would allocate the remaining increment of water use to
projects which best meet city goals, rather than providing additional water
service strictly on a first -come, first- served basis. So long as water use
exceeds safe yield, the ordinance would allocate only part of any increased
supplies to new development, and the rest to reducing the disparity between safe
yield and consumption, so eventually water use would again be within safe yield
of supplies."
25 Revise policy 3.2 to read: "All potential supply alternatives will be
explored. City efforts to provide supplemental water supplies will generally
follow the priorities below. While the city has taken some action on a range of
potential sources, it cannot pursue each potential source with equal effort.
The priorities are intended to focus city efforts on those sources which will:
(1) be able to supply water earlier even though the amounts are relatively
modest; (2) require the least capital funding; (3) cause the least environmental
impact, in terms of both the project sites and commitment to growth- inducing
resource expansions; (4) offer the most city control. The order indicates
general priorities, not a strict sequence.
More efficient use of existing supplies (conservation);
More complete use of sources already used by the city;
Development or reactivation of sources in and near the city;
Development of other new sources within San Luis Obispo County
Development of new sources outside San Luis Obispo County."
�J
Page. Proposed he ange
25 Throughout policy 3.4, clarify the references to water - supply projects vs.
land- development projects. For example, item A would read:
"A. The city has at least completed environmental review and has authorized
preparing construction plans for one or more water - supply projects which would
provide the safe annual yield needed to support potential land - development
projects within the city, including the proposed land - development project"
25 Add to policy 3.4, item D: "(Users of the well water would bear additional
costs of treatment.)"
25 Revise policy 3.5 to read: "The city encourages frugal use of on -site well
water within the city for uses such as construction or landscape irrigation."
26 Revise program 3.1 to read: "The City will pursue the following water sources
Specific steps to prepare feasibility studies, environmental documents,
financing programs, and designs will be spelled out in the city's five -year
capital facilities plan and two -year budgets. Because some sources outlined
below will require more evaluation or the cooperation of other agencies, a
schedule of water availability cannot be assured (Figure 6). The following
priority listing of potential projects is intended to focus city efforts
consistent with policy 3.2.
A. Conservation measures to reduce long -term increases in water use;
B. Drawing more water than usual from Santa Margarita Reservoir during wet
periods and thereby "banking" some of the city's entitlement to water in
Whale Rock Reservoir, for use during dry periods ( "cooperative use ");
2. Developing wells for irrigation of the municipal golf course and other city
parks or school grounds;
3. Reactivating unused wells, springs, or small reservoirs for use in
prolonged droughts;
4. Developing new, small stream diversions whose flows could be processed
through existing reservoirs and treatment facilities;
5. Enlarging Santa Margarita Reservoir by raising Salinas Dam spillway;
6. Participating with the county or other agencies in a regional source, such
as Nacimiento Reservoir connection or Coastal Branch of the State Water
Project.
Paee Pronosed change
26 Add a new program for well permits and standards:
Program 3.2 The city will by ordinance establish permit requirements and
standards for private wells.
Time frame: Provisions adopted by January, 1988. If the city
cannot prepare and adopt its own requirements by this date, it
will adopt the County of San Luis Obispo requirements as an
interim measure.
Responsible parties: Public Works Department; Community
Development Department; City Council
Funding: City general fund.
26 Add a new program concerning city use of wells for landscape irrigation:
Program 3.3 The city will evaluate the reactivation or installation of wells
within the city for landscape irrigation.
Time frame: Continuing.
Responsible parties: Public Works Department; Community
Development Department, City Council
Funding: City general fund.
27 Add a sentence to policy 5.2 to read: "The system should be designed to enable
service for uses consistent with the general plan, within the urban reserve."
28 Add to policy 6.1: "Programs to fund supplemental water projects should be
consistent with the growth management policies of the general plan."
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GENERAL PLAN
WATER
MANAGEMENT
ELEMENT
E� ....�...:_,
city of San luis OBISpo
35.87
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City of San Ii,; c Obispo
General Plan
This element was adopted February 24, 1987, by City Council Resolution No.
6180A. The following amendments have been adopted:
Subject Resolution No. Date
'1.1 � 1 •1
PmW Fap a
Allen Settle
CITY OF SAN
.�I�D7I�S OBISPO PLVOTIM CMOMWION
Randy
Dattmer, Chairman
Charles Crot se
Dolma Duerk
Patrick Gerety
Janet Kourakis
Jerry Reiss
Richard Schmidt
EEPARTMEM OF CCMKMi '!'Y DEVELOPMM
Mike MUltari, Director
Glen Matteson, Project Planner
PUBLIC WORKS DEPARTNEPP
Dave Romero, Director
Bill Hetland, Utilities Manager
Hal Fones, Utilities Engineer
IlFIlmDITCTICIUJ.................................................. 1
................................................ 3
Climate and Rainfall
...................................... 3
Water Use ................................................. 3
Existing Water Soames .............0.......000............ 9
Projected Water Requirements .............................. 10
Treatment► Storage, and Distribution ...................... 12
Water Costs and Revenues ...0000 ........................... 12
Dealing with Near-term Ccnlditi.ons 13
Potential Water Sources ................................... 15
r1.• '• M1?. � .,.•�C•' 7
ServiCie Area and Population ...............................
- Rainfall History ...............................
19
Water Use and CWwA nation ................................
Figure 2
22
Water Supplies: Supplemental Sorg ......................
5
26
Water Quality .............................................
29
Water Treatment,, Storage► and Distribution ................
- Current Water Use ...................................
29
Water Revenues and Financing ...........0.0 ................
Figure 5
30
Appendix A - Previous Water Studies
Table 1 - Exceeding the Safe Yield - Required
Water -Use Reductions 14
Figure 1
- Rainfall History ...............................
0.0..
4
Figure 2
- Average Monthly Rainfall ............................
5
Figure 3
- Water Uses ..........................................
6
Figure 4
- Current Water Use ...................................
7
Figure 5
- Regional Setting ....................................
8
Figure 6
- Projected Water RAS & Supplies ............
11
Figure 7
- Water Situation & Response ....0 ................00.0
25
INTRODUCTION
Purpose
The city's general plan guides the use and protection of various resources to meet
community purposes. The general plan is published in separately adopted sections,
called elements, which address various topics such as land use, housing,
circulation, public safety, and parks. Previously, water resources were discussed
primarily in the Conservation Element (1973), which dealt with several other
resources.
The city decided to adopt this separate element specifically addressing water
resources because of the vital role of water resources in the community and the far
reaching impacts of water policies on community growth and character. This element
outlines how the city plans to provide adequate water for its citizens, consistent
with the goals and policies of other general plan elements.
This element is coordinated with the Land Use, Open Space, Conservation, and Housing
elements. The Land Use Element states the city's basic position on growth and
designates appropriate uses for areas of the community, which this element
translates into potential water demand. The Housing Element describes development
and maintenance of the housing supply and management of housing demand, which. relate
to water needs and the possible allocation of limited water resources. Both the
Land Use Element and the Open Space Element provide for areas which should not be
developed and therefore should not receive water for urban uses.
Although this is the first Water Management Element, the city has prepared several
other documents concerning water. In addition to the Conservation Element noted
above, the city has prepared the water studies and operational plans listed in
Appendix A. The most recent and comprehensive of these other documents is the draft
Water Management Plan, published in April 1986, from which this element evolved.
That draft plan and additional staff reports prepared during spring and summer of
1986 contained detailed information on a wide range of water supply alternatives and
potential changes to the city's water treatment plant, water mains, and neighborhood
water tanks.
Immediately following adoption of this Water Management Element, the city will
refine the Water Management. Plan for consistency with the element and adopt it as a
guide for funding and carrying out specific conservation, water -supply, and
treatment, storage, and distribution projects. The City Council would decide to
actually proceed with projects or changes to operations or water rates during public
hearings on city budgets, capital facility programs, or other specific agenda items.
Public Participation
Before adopting or revising any general plan element, the Planning Commission and
City Council must hold public hearings. The city publishes notices in the local
newspaper to let citizens know about the hearings at least ten days before they are
held.
The city adopted this element following workshops and hearings before the Planning
Commission and City Council during the summer and fall of 1986. As part of the
public review process, the city also prepared and distributed an environmental
impact report on the draft Water Management Plan and the draft Water Management
Element.
Anyone may suggest or apply for amendments to general -plan elements. Amendments are
considered by the Planning Commission three times each year. The city will probably
update this element about every five years, or more frequently if necessary.
For More Information
For more current or more detailed information concerning the topics covered in this
element, contact the Community Development Department at City Hall, 990 Palm Street,
(P.O. Box 8100), San Luis Obispo, CA, 93403-8100; phone 805-549-7160.
2
INFORMATION
Background
An adequate supply of clean water is often taken for granted, though it is one of
the basic needs for life and for an enjoyable community.
The community has been discussing the relationship between water and city growth and
possible sources of additional water almost continually since the early 1970's, when
the city began to more deliberately relate all types of resources to planning for
future development. The discussion included the following major issues:
The desirability of continued urban growth and its effects on quality of life;
Appropriate growth rates and the desirable ultimate size for the city;
Water supply as a natural limit to urban growth;
The appropriateness of continuing current water -use patterns;
The best alternative sources of supplemental water to accommodate whatever
growth was projected or desired;
The costs of supplemental water and who should bear the costs;
How great a risk the community should take in exceeding the estimated limits of
its current water supplies, considering the severity of water -use restrictions
that would be needed during a drought;
The amount and type of development that should be approved as the city
approaches and exceeds the estimated capacity of its current water sources;
The reliability of water -use and water -supply estimates and projections.
Climate and Rainfall
Water use and supply are both closely tied to weather patterns. Water use rises
when weather is hot and dry, while the city's supplies are simply rainfall captured
in reservoirs. Therefore, supplies can be strained during prolonged droughts.
San Luis Obispo has a Mediterranean climate, averaging about 22 inches of rain per
year. Annual rainfall, however, has ranged from seven to 56 inches per year in the
last 1.15 years (Figure 1). Summers are warm and often foggy. Winters are cool, but
rarely freezing, with rain coming mostly in December through February. Measurable
rain rarely falls from June through September (Figure 2). The reliable yield of the
city's reservoirs is determined by the driest six-year period on record, which was
1945 to 1951. During this interval, annual rainfall averaged 16 inches, about 73
percent of the 115 -year annual average.
Water Use
The volume of water is often measured in acre-feet, the amount of water which would
cover one acre to a depth of one foot, about 326,000 gallons. Often, and throughout
this element, water use is measured in acre-feet per year. (City water customers
are billed according to their usage in hundreds of cubic feet over a two-month
period. One acre-foot contains about 436 hundred cubic feet.)
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Figure 2
AVERAGE MONTHLY RAINFALL
Source: City of San Luis Obispo Public Works Department
67
In the city, water is used by households, businesses, and institutions for many
purposes (Figure 3). Figure 4 shows annual water use.
Figure .3.
WATER USES
Commercial (21.4%)
Bathroom Uses (25%)
I
Other Uses (10%)
I
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(61%)
Churches, Schools (11.5%)
Government Agencies, Parks (6%)
Outdoor Uses (26%)
Source: City of 9.L.O. CMSM Advisory Conunirree, 1987
This chart shows metered water use, which accounts for about 91 percent of all water passing
through the water treatment plant. All city water customers have meters. The remaining nine
percent of total treated water is accounted for by fire fighting and hydrant testing, flushing
impurities from water mains, water system leaks, and inaccurate meters.
6
111
Figure 4
CURRENT WATER USE
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Exi-s-ting Water Sources
San Luis Obispo gets its water from two lakes behind dams, one located 20 and the
other 25 miles from the city (Figure 5). These reservoirs store creek runoff from
rainfall on lands surrounding the lakes. Each reservoir can provide a certain
maximum amount of water year after year without being drawn down to an unacceptably
low level, considering the period of lowest recorded rainfall. This amount of water
is called the safe annual yield. (Yield is measured in acre-feet per year.) For
the city's reservoirs, safe annual yield is based on the driest six-year period
experienced in the last 115 years.
The safe annual yield estimates for the reservoirs have been revised by water
engineers since they were built, to reflect experience with rainfall, runoff, and
build-up of silt, which reduces storage capacity.
Salinas Dam (Santa Margarita reservoir), which can store about 23,300 acre-feet, has
a safe annual yield of 4,800 acre-feet per year. The city is entitled to all the
water stored in this reservoir. However, water can be stored only after enough has
been released to maintain certain water levels along the Salinas River downstream,
to protect the rights of downstream users. The California Water Resources Control
Board sets rules which govern flow and storage. This reservoir is owned by the U.S.
Army Corps of Engineers and operated by the San Luis Obispo County Flood Control and
Water Conservation District, which is governed by the county Board of Supervisors.
Whale Rock reservoir can store about 40,660 acre-feet. It has a safe annual yield
of about 4,400 acre-feet per year. Of this, the city is entitled to 2,057 acre-feet
per year. Also, the city treats water for Cal Poly, which is entitled to 823
acre-feet per year for uses other than irrigation. (Throughout this element, Cal
Poly's entitlement and consumption are considered part of the city total since Cal
Poly is a city water customer, even though the campus is not within the city
limits. Cal Poly also uses some untreated Whale -Rock water for irrigation, which is
not included in this element's figures.)
Whale Rock reservoir is owned jointly by the city and the by state, which uses its
allocation for Cal Poly and the Men's Colony prison. The Whale Rock Commission sets
operating policy. This commission is comprised of city, Cal Poly, Men's Colony, and
state Department of Water Resources representatives. City staff operate the dam.
Enough water must be released from Whale Rock dam to provide for Cayucos' wells
located just downstream from the dam. The Whale Rock Commission has sold surplus
water to Cuesta College (about 100 acre-feet per year).
The safe yield figures are much smaller than the storage figures because during a
drought a reservoir would not be full of water. Also, all the water in a lake is
not fit to use, since it becomes warmer and more contaminated as it becomes
shallower. The two reservoirs have very different storage and yield figures because
Santa Margarita Reservoir, in comparison with Whale Rock, has a larger watershed
(runoff collection area) in relation to the capacity of the lake. Also Santa
Margarita water evaporates more quickly due to higher altitude and temperatures, and
more wind.
Silt is slowly filling both reservoirs. Engineers have estimated that this
siltation reduces the combined safe annual yield of the reservoirs by roughly 25
acre-feet per year each year, so that by the year 2015 the yield will have been
reduced by nearly 800 acre-feet.
E
The quality of water from the reservoirs is very good in comparison with many other
municipal sources throughout the state.
In addition to the city water system, a few private wells and stream withdrawals are
used for landscape irrigation. Also a water -bottling company uses a hillside spring
and an ice company uses well water. The city has stopped using creek supplies near
Cuesta Grade and wells which were used before the 1950's, due to small and less
reliable yields and relatively poor water quality. The city is considering
reactivating these sources for use in drought emergencies.
Proiected Water Requirements
Water demand is expressed as the number of acre-feet per year which the city should
be prepared to deliver for all desired uses. Based on recent water -use
measurements, the city assumes that water use will be 0.2 acre-feet per person per
year. In other words, one acre-foot of water will meet the needs of five city
residents plus all nonresidential uses (businesses, parks, and schools) if the
relationship between resident population and other uses remains about the same as in
recent years. Using these assumptions, and population projections derived from the
Land Use Element, Figure 6 shows city water needs to the year 2015. This figure
includes an allowance of up to 150 acre-feet per year for Cuesta College. It also
reflects the additional water needed to compensate for gradually reduced yield of
existing reservoirs due to siltation.
If San Luis Obispo grows as outlined in the Land Use Element, the city will need
about 9,700 acre-feet per year (an increase of 2,000 acre-feet) by the mid 1990's.
By the year 2015, it would need about 12,000 acre-feet per year (an increase of
about 4,300 acre-feet). As Figure 6 shows, at times (such as the late 1980's) the
city's supply in terms of safe annual yield may not equal projected requirements.
At other times the city may have more than enough water. The actual dates when
supplemental water will be available and the total quantities to be available cannot
be predicted with certainty. If supplemental -water projects are delayed or if
droughts occur, the city will have to manage demand so requirements do not reach the
level projected in the graph. Under other conditions, water demand may exceed that
projected in the graph.
10
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Treatment. Storage. and Distribution
The existing reservoirs generally provide good quality water, though it must be
treated to meet health and esthetic standards. The City's water treatment plant in
Stenner Canyon purifies the water to meet these drinking -water standards. Compounds
are added to help remove sediment and kill bacteria. To further remove impurities,
the water flows through carbon filters.
From the treatment plant, water is pumped to tanks on hillsides around the city.
From the tanks, it flows through pipes to customers and to fire hydrants. The
existing network of pumps, pipes, and tanks determines water pressures (pounds per
square inch) and delivery rates (gallons per hour) which can be provided to various
areas of the city. The pressures and rates in turn determine how far up the
hillsides and how far out development can be served while still meeting city
standards for customer convenience and fire safety.
The water distribution system was developed along with the city. The oldest
existing pipes date from the early 1900's. While the city has upgraded the system
over the years, parts of it do not meet current standards. Some lines do not
provide adequate flow to meet modern fire -fighting requirements. The city is
divided into several pressure zones, since some neighborhoods are at higher
elevations than others. Large, sudden changes in pressure from fire fighting or
cycles of daily use along certain water mains and between certain pressure zones can
damage the pipes. The city now requires looped pipes to serve new neighborhoods and
major developments, so if one pipe breaks water service can be maintained. However,
some areas served by only one line have been developed.
Pumps which move water within the system use electricity. Evaluations of possible
changes to the system have shown that electricity use and pumping costs could be
reduced. The city must decide if the costs of making such changes can be justified
by improved service and pumping -cost savings.
The city maintains maps showing the location, size, and type of water lines and fire
hydrants and the city uses a computer simulation of the water system to help operate
it and to evaluate proposed system changes and development projects.
Water Costs and Revenues
The city budgets its water activities separately from other city services and has a
long-standing policy that the water "enterprise" should pay its own way. Those
making new connections to the water system must pay for their meters and for their
share of the cost of developing the existing water system. Water customers are.
billed according to the diameter of the pipe from their meter and the amount of
water they use.
In 1986-87, the city water system budget was $2.76 million. In that year, the
average cost for an acre-foot of water was about $340, or about $68 per city
resident, including all operating, debt -service, and administrative costs.
12
The supplemental water projects to serve potential development within the urban
growth limit and projects to expand the capacity of the treatment, storage, and
distribution system as outlined in this element would cost about $19 million in
1986. Dividing this cost by the additional population which would be accommodated
by the increased water supply results in about $1,300 per person. Dividing this
total cost by the total future population results in about $360 per person. These
figures provide a rough comparison of charging water -project costs to new
development or to all customers, though they do not imply specific water rate
changes or development fees. These figures may change significantly if project
descriptions or other assumptions change.
Dealing with Near-term Conditions
City water use has exceeded the safe annual yield of existing supplies since 1984.
After a public hearing in November of that year, the City Council decided to:
Continue to monitor water use and reservoir conditions
Prepare the water management plan that would guide city efforts to conserve
water and to obtain more water;
Not restrict water use or real-estate development.
In 1985, water use exceeded safe yield by about five percent, and projected 1986 use
is expected to exceed safe yield by about eight percent. Although annual changes in
water use are related to such variables as the weather and the economy, the
continuing trend of increasing total water use has been due primarily to the
construction of more houses, apartments, and businesses. When water use from
projects under construction during 1986 is considered, total water use will probably
exceed safe yield by nearly ten percent. The more usual water use exceeds safe
yield, the more frequently and the more severely water use must be cut back to avoid
running out of water during periods of low rainfall.
The city is seeking several supplemental water supplies which could be available by
the early 1990's, including conservation, drawing on Salinas and Whale Rock
reservoirs in a way that would allow the combined safe yield to be slightly more
than now estimated, using groundwater for landscape irrigation, and increasing the
capacity of Salinas Dam. However, a major supplemental source of water, such as the
coastal branch of the state aqueduct or a distribution system from Nacimiento
Reservoir, probably will not be available until the mid to late 1990's (see Figure
6, which shows projected requirements and supplies).
If the city's usual water use did not exceed the safe yield, reductions from usual
use would probably never be needed. However, when use exceeds safe yield, cutbacks
from usual use may be needed to avoid running out of water. For example, when use
exceeds safe yield by ten percent, the city would have to reduce consumption by five
percent in about one out of eight years. About once in 25 years it would have to
reduce consumption by five percent in one year and by ten percent in the following
year. About once in 100 years the city would have to cut back during four
consecutive years, about five percent in the first and increasing to about 23
percent in the fourth year. Alternatively, the city might be able to quickly
develop temporary or permanent supplemental supplies, such as groundwater pumping,
which could forestall the need for water -use cutbacks. These estimates are based on
evaluations of rainfall records, the storage and refill characteristics of the
reservoirs, and observed water -conservation behavior during droughts in San Luis
Obispo and other communities.
13
These estimates are derived from San Luis Obispo's 115 -year record of rainfall,
including the six-year dry spell used to determine safe annual yield. A drought
longer than six years may occur, though none has been experienced since 1869. Also,
while the probability of a six-year drought appears small (once in 115 years), such
a drought could begin any year. Less severe droughts are expected to occur more
frequently. Table 1 shows how much and how often the city would have to reduce
water use to avoid running out of water, if usual use exceeded safe yield by
percentages ranges from five to 20.
Table 1
EXCEEDING THE SAFE YIELD - REQUIRED WATER -USE REDUCTIONS
If usual water use exceeds
safe annual yield by: 5% 10% 15% 20%
About one year in eight, water
use would have to be reduced: 5% 5% 5% 5%
About once in 25 years, water use would
have to be reduced two consecutive years
and the maximum reduction in one
year would have to be about: 5% 10% 15% 20%
About once in 50 years, water use would
have to be reduced three consecutive years
and the maximum reduction in one
year would have to be about: 10% 18% 25% 35%
About once in 100 years, water use would
have to be reduced four consecutive years
and the maximum reduction in one
year would have to be about: 10% 23% 34% 39%
To minimize the risk of having to use less water than usual during droughts, the
city would not exceed the safe annual yield. Or, it would have standby sources
ready to use that would at least temporarily increase total safe yield.
A five percent reduction in water use can usually be achieved by making the public
more aware of careful water use, through information efforts or increased rates. A
15 percent reduction would probably require mandatory conservatiion measures, such
as watering only on certain days. A 25 percent reduction would require cutbacks in
landscape watering and elimination of some water uses, such as washing cars. A 25
percent reduction is difficult to achieve and maintain.
A 35 percent reduction approaches the levels met by northern California communities
during the 1970's drought. This reduction could be achieved only by eliminating
most landscape irrigation and imposing extra charges for water use over certain
amounts. Reductions of 35 percent or more are very hard to achieve and nearly
impossible to maintain for a long time without significant changes in peoples'
behavior and in community character.
14
b. Wells in city parks (for landscape irrigation, and possibly domestic use) and -
other minor sources in and near the city.
C. Cooperative use of Salinas and Whale Rock reservoirs, which the city already
does to some extent. The city now draws on both sources, using Salinas water
first since that reservoir is filled more rapidly than Whale Rock from a given
amount of rainfall and since it loses water more rapidly due to evaporation.
Under this alternative, the city would try to use Salinas water more and "bank"
its entitlement to Whale Rock water for use in drier years. This approach is
expected to yield an additional 500 acre-feet per year. This approach requires
the approval of other agencies with entitlements to Whale Rock Water, which the
city has sought but not yet obtained.
d. Expand Santa Margarita reservoir by raising the spillway of Salinas Dam. Doing
so would yield up to 1,300 more acre-feet per year.
e. Participate with other agencies in the county to extend the Coastal Branch of
the State Water Project, which would yield about 3,000 acre-feet per year for
the city and 23,000 acre-feet per year for the county as a whole; or, extend a
conduit from Nacimiento Reservoir or develop other regional sources of water..
The following additional sources were investigated.
Develop a reservoir on Santa Rita Creek in the eastern slopes of the Santa
Lucia Mountains (Salinas River watershed). A tunnel could carry water
southwest to the existing Whale Rock reservoir. This project could yield up to
6,000 acre-feet per year. Smaller versions yielding 3,000 or 4,500 acre-feet
per year have been investigated.
Salinas Reservoir conjunctive use. Water released from Salinas Dam would soak
into the ground downstream, to be pumped out from wells. This approach could
store more water without enlarging the reservoir. Preliminary studies found no
suitable sites for this approach.
Wastewater reclamation. Effluent from the city's wastewater treatment plant
would be used to irrigate Laguna Lake Park and the golf course, replacing up to
270 acre-feet per year of reservoir water.
Cantera Reservoir. A new dam would. be built on the Salinas River, downstream
(northwest) from the existing Santa Margarita reservoir, to yield about 4,600
acre-feet per year.
4. Additional suoolies. The city considered seeking "as much water as possible as soon
as possible," to support development beyond the scope of the adopted general plan.
This approach could include requesting more water from the State Project or
developing additional sources.
The Water Management Plan also contains an evaluation of the water treatment, storage,
and distribution system within the city. It recommends several actions to improve water
treatment and distribution economy, reduce damage to the system from sudden pressure
changes, and to increase reliability for fire fighting. The plan calls for the following
actions involving water treatment:
Change personnel schedules at the treatment plant.
Increase the amount of chemical testing which can be done at city facilities.
12
PROJECT DESCRIPTION AND ALTERNATIVES
The Water Management Element and Water Management Plan would establisholi�Cj�S-On water
service and would direct city staff to work on project plans and financial arrangements
to obtain supplemental sources of water. Adoption of the management plan would be a
major step in pursuing specific supplemental sources of water.
The following are alternatives to the cource of action outlined in the Water Management
Element and the Water Management Plan.
1. No Proiect. Under the no -project alternative, the city would adopt a water
management plan, but it would not pursue any supplemental source of water. The
city's water supplies would be used the same as now (in terms of types of uses and
average amount per person or per unit of economic activity). Siltation would
gradually reduce the capacity and safe annual yield of existing reservoirs. This
alternative has been rejected as infeasible for the long term.
2. Conservation only. Under the conservation alternative, the city would make a
long-term commitment to use water more efficiently than now and possibly to
eliminate some uses of water which the community would find nonessential. The
long-term commitment would result in using water about 10 percent more efficiently
than the city recently has. Development requiring additional water would be allowed
only if customers reduced water consumption to accommodate the new demand. Over the
long term, conservation would barely offset reductions in safe annual yield caused
by siltation of the reservoirs.
While the Water Management Element includes conservation as one source of additional
water, for purposes of environmental evaluation the "conservation alternative"
assumes that additional water users would be accommodated only as a consequence of
existing users being more efficient. Conservation would be the only supplemental
source.
The California Department of Water Resources indicates that communities have
achieved conservation in the range of five to 35 percent, depending on the public's
perception of the need to conserve and the types of mandatory water -saving steps
which have been carried out. Five to ten percent conservation is seen as a
reasonable goal to be achieved by a sustained effort in years of normal or higher
rainfall. Reductions in per -person water use greater than ten percent, in
communities similar to San Luis Obispo, could be expected only during droughts.
Conservation exceeding ten percent would require measures such as replacing fixtures
in most existing buildings, substantial changes to water rates, and continuous,
independent monitoring to prevent over -watering or misdirected watering for
landscape irrigation.
The conservation alternative evaluated here would yield the equivalent of 770
acre-feet per year.
3. Water Management Element/Plan. With adoption of the plan, the city would pursue the
following supplemental sources of water.
a. Conservation, which would yield the equivalent of up to 387 additional
acre-feet per year (five percent reduction from recent per capita water use)
during times of normal rainfall, and more during droughts.
11
Figure 3.
WATER USES
Source: City of S.L.O. Citizens Advisory Committee, 1983
10
r
_ The treatment plant can process up to 11.5 million gallons per day, enough for a city
population of 44,000 to 47,000 people, depending on per -person water use. The existing
pipes and tanks can serve most areas within the city limits, up to 240 feet to 600 feet
elevation, depending on pressure zone.
Water is used by households, businesses, and institutions (Figure 3). Manufacturing and
agricultural irrigation use very little city water.
The city gets its water from two lakes behind dams, one located 20 and the other 25 miles
from the city. These reservoirs store runoff from rainfall on lands surrounding the
lakes. Each reservoir can provide a certain maximum amount of water year after year
without being drawn down to an unacceptably low level, considering the period of lowest
recorded rainfall. This amount of water is callcd the safe annual yield. The safe
annual yield estimates for the reservoirs have been revised by water engineers since they
were first built, to reflect experience with rainfall, runoff, and build-up of silt,
which reduces storage capacity. Storage is measured in acre-feet, the amount of water
which would cover one acre to a depth of one foot, about 326,000 gallons. Yield is
measured in acre-feet per year.
Salinas Dam (Santa Margarita reservoir) which can store about 23,300 acre-feet, has a
safe annual yield of 4,800 acre-feet per year. The city is entitled to all the water
stored in this reservoir. However, water can be stored only after enough has been
released to maintain certain water levels along the Salinas River downstream, to protect
the rights of downstream users. State rules govern flow and storage.
Whale Rock reservoir can store about 40,660 acre-feet. It has a safe annual yield of
about 4,400 acre-feet per year. Of this, the city is entitled to 2,057 acre-feet per
year. Also, the city treats water for Cal Poly State University, which is entitled to
823 acre-feet per year for uses other than irrigation. Throughout this report, Cal
Poly's entitlement and consumption are considered part of the city total since Cal Poly
is a city water customer, even though the campus is not within the city limits. Cal Poly
also uses some untreated Whale -Rock water for irrigation. This water is not included in
the following discussions.
Silt is slowly filling both reservoirs. This siltation is expected to reduce the safe
annual yield of the reservoirs by about 995 acre-feet per year total over the next 40
years.
The city's yearly water use has exceeded the combined safe annual yields of Salinas and
Whale Rock reservoirs since 1984. Yields and total use are summarized in Figure 2.
G
APPENDIX B
DROUGHT SCENARIOS
This illustration relates the extent by which city water use exceeds the safe annual
yield of its supplies (five to twenty percent), the expected frequency of droughts
of certain durations (three to six years), and the amount of reduction from usual
water use which would be required each year of the drought to avoid running out of
water.
Excess over
Estimated reduction
from
usual
water use
safe annual
yield
Yr. Yr.
Yr.
Yr.
Yr.
Yr.
1 2
3
4
5
6
5%
0 0
-5$
-5%
-10%
-10%
10%
0 0
-5%
-10%
-18%
-2.3%
15%
0 0
-5%
-15%
-25$
-34%
20%
0 0
-5%
-20%
-35%
-39%
These situations
could occur
as frequently as
once every
8 years or so.
These situations
could occur
about once every
25 years or so.
These situations
could occur
i
i
about once every
50 years or so.
These situations
could occur
about once every
100 years or so.
Evaluation of Local Water Resource Alternatives. July 1986, Leedshill-Herkenhoff,
Inc., for City of San Luis Obispo.
Ground Water Study = Samar Luis Obispo Airport Area (draft), September 1986,
Timothy S. Cleath for Willdan Associates, for County of San Luis Obispo.
APPENDIX A
PREVIOUS WATER STUDIES
Report Qn_ Master Water Ind Sewerage Plan. May 1972, CDM, Inc., for County of San
Luis Obispo.
Water Supplv Background Information. March 1974, Ad Hoc Task Force on Resource
Inventory for City of San Luis Obispo..
Proposed General P1an,Revision - Part One: Resource Inventory and Interpretations,
and Part Two: r-owth Alternativesnils Evaluations. 1976, Community Development
Department for City of San Luis Obispo.
City of San Luis Obisno Water Supply Study. April 1977, Engineering Science, Inc.,
for City of San Luis Obispo.
Islay Hill Development Water Supply Study. February 1979, City Utilities
Superintendent for City of San Luis Obispo.
Recommended Water Conservation Plan. 1983, Citizens' Advisory Committee for City of
San Luis Obispo.
Preliminary Evaluation gL Groundwater Availability ffsr Proposed Margarita Expansion
Area, August 1983, Pacific Geoscience, Inc., for City of San Luis Obispo.
Council Agenda Renort: Public Hearing ga Water Resource Deficiency. November 1984,
Public Works Department for San Luis Obispo City Council.
Annual Water Operations Plan. various years, Public Works Department for San Luis
Obispo City Council.
San Luis Obispo County Master Water Plan Undate March 1986, Department of Water
Resources and San Luis Obispo County Flood Control and Water Conservation District.
Draft Water Management Plan. April 1986, Public Works Department for City of San
Luis Obispo.
Council Agenda e o : Water Management Study Session April 1986, Public Works
Department for San Luis Obispo City Council.
Water Management -Plan Draft. Environmental Imoact Report, April 1986, Community
Development Department for City of San Luis Obispo.
Council end Reoort: Texaco Carwash Appeal. June 1986, Community Development
Department for San Luis Obispo City Council.
Council Agenda Renort: Water Management Plan. August 19, 1986, Public Works
Department for San Luis Obispo City Council.
6. Water Revenues and Financing
Policy 6.1 The city's water system will be operated as an enterprise activity,
with costs to be borne by water fees and charges. Costs of operating,
maintaining, and replacing the water system will be borne by all
customers. Costs of developing supplemental sources and of expanding
the water system to serve new development shall be borne primarily by
those making new connections to the system, in proportion to expected
water use. Some portion of the cost --such as investigation,
environmental review, project selection, and design-- for large-scale,
long-term supplies may be borne by the whole community. Programs to
fund supplemental water projects should be consistent with the growth
management policies of the general plan. [Housing: page 8, item IV;
p. 47, item 20]
Cuesta College will pay the city's costs for any water it receives
from the city.
Program 6.1 The city will maintain and periodically revise its schedule of charges
for water service. The city will prepare a development fee schedule
to fund supplemental water projects and related expansion of the
treatment, storage, and distribution system.
Time frame: Annual water rate evaluation; development fees to be
adopted by July 1987 and updated as required.
Responsible parties: City staff; City Council.
30
4. Water Ouality
Policy 4,1 Water quality will be appropriate for the intended use.
Program 4.1 The city will continue to treat water to meet state and federal
standards. Operational improvements to maintain treatment quality and
increase reliability will be programmed in the city's capital
facilities plan. Precise project scheduling and operating procedures
will be described in the annual water operations plan.
Time frame: continuing
Responsible parties: Public Works Department; City Council
Funding: Water operations revenues; development fees.
5. Water Treatment. Storase. and.Distribution
Policy 5.1 The city will be the only purveyor of water within the city.
Policy 5.2 The city's water treatment, storage, and distribution system will be
able to reliably and economically meet peak citywide demands and
demands from subareas of the city, including normal operations,
emergencies, and fire flows. The system should be designed to enable
service for uses consistent with the general plan, within the urban
reserve..
Policy 5.3 Water operations will minimize energy use and will incorporate all
cost-effective energy production facilities.
Program 5.1 The city will continue to monitor its treatment, storage, and
distribution system to identify potential improvements and
deficiencies triggered by development. Cost-effective improvements
will be programmed in the city's capital budget.
Time frame: continuing
Responsible agencies: Public Works Department; City Council
Funding: Water operations revenues; development fees.
29
Program 3.2 The city will by ordinance establish permit requirements and standards
for private wells.
Time frame: Provisions adopted by January, 1988. If the city cannot
prepare and adopt its own requirements by this date, it will adopt the
County of San Luis Obispo requirements as an interim measure.
Responsible parties: Public Works Department; Community Development
Department; City Council
Funding: City general fund.
Program 3.3 The city will evaluate the reactivation or installation of wells
within the city for landscape irrigation.
Time frame: Continuing.
Responsible parties: Public Works Department; Community Development
Department; City Council
Funding: City general fund.
28
E. The well -water distribution system or a separate system is
designed and constructed, or a separate system is provided, to
eventually be connected to the city water system.
Policy 3.5 The city encourages frugal use of on-site well water within the city
for uses such as construction or landscape irrigation.
Policy 3.6 Installation of any well within the city shall be subject to city
approval.
Program 3.1 The City will pursue the following water sources. Specific steps to
prepare feasibility studies, environmental documents, financing
programs, and designs will be spelled out in the city's five-year
capital facilities plan and two-year budgets. Because some sources
outlined below will require more evaluation or the cooperation of
other agencies, a schedule of water availability cannot be assured
(Figure 6). The following priority listing of potential projects is
intended to focus city efforts consistent with policy 3.2-
1. A. Conservation measures to reduce long-term increases in water
use;
B. Drawing more water than usual from Santa Margarita Reservoir
during wet periods and thereby "banking" some of the city's
entitlement to water in Whale Rock Reservoir, for use during dry
periods ("cooperative use");
2. Developing wells for irrigation of the municipal golf course and
other city parks or school grounds;
3. Reactivating unused wells, springs, or small reservoirs for use
in prolonged droughts;
4. Developing new, small stream diversions whose flows could be
processed through existing reservoirs and treatment facilities;
5. Enlarging Santa Margarita Reservoir by raising Salinas Dam
spillway;
6. Participating with the county or other agencies in a regional
source, such as Nacimiento Reservoir connection or Coastal Branch
of the State Water Project.
Time frame: 1986 through mid 1990's.
Responsible parties: City staff, City Council, Whale Rock Commission,
San Luis Obispo County and other agencies
delivering water within the county.
Funding: Connection fees for new development and water rate
increases.
27
3. Water Supplies: Supplemental Sources
Policy 3.1 In deciding appropriate sources of supplemental water, the city will
evaluate impacts on other users of the water and other environmental
impacts, total and unit costs, reliability, water quality, development
time, and quantity available.
Policy 3.2 All potential supply alternatives will be explored. City efforts to
provide supplemental water supplies will generally follow the
priorities below. While the city has taken some action on a range of
potential sources, it cannot pursue each potential source with equal
effort. The priorities are intended to focus city efforts on those
sources which will: (1) be able to supply water earlier even though
the amounts are relatively modest; (2) require the least capital
funding; (3) cause the least environmental impact, in terms of both
the project sites and commitment to growth -inducing resource
expansions; (4) offer the most city control. The order indicates
general priorities, not a strict sequence.
More efficient use of existing supplies (conservation);
More complete use of sources already used by the city;
Development or reactivation of sources in and near the city;
Development of other new sources within San Luis Obispo County
Development of new sources outside San Luis Obispo County.
Policy 3.3 The city will not compete with local agricultural use of groundwater
or damage wildlife habitat through reduced stream flows in obtaining
long-term sources of supply.
Policy 3.4 The city does not encourage but may consider wells to provide domestic
water for a private development within the city. Such a well may be
operated by the project owner only for the owner's use. If the well
serves any user in addition to the project owner, it must be operated
by the city (Policy 5.1) Such wells may be used only when:
A. The city has at least completed environmental review and
authorized preparing plans for a water -supply project or projects
which would provide the safe annual yield needed to support potential
land development within the city limits, including the proposed
land -development project. [Land Use: 9, 21]
B. The City Council approves the well proposal as part of a specific
land -development project approval, and the proposed well system meets
all city standards;
C. A qualified, independent hydrological investigation demonstrates
that the well(s) reliably can provide sufficient quality and quantity
of water for the proposed land -development project.
D. The owner or developer financially guarantees any treatment system
required for the well water to meet state and federal standards and
any cost of future connection to the city water system. (Users of the
well water would bear additional costs of treatment.)
26
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Program 2.4 To prevent development from jeopardizing water service when supplies
are not adequate, the city will adopt an ordinance which controls
increases in water use by limiting new development and changes in land
use. As outlined in policies 2.3 and 2.4 (Figure 7), depending on the
severity of the water shortage, the ordinance could prevent
construction or changes in building occupancy which would increase
water use. Also, as the maximum acceptable level of risk in providing
adequate water for the community is reached, the ordinance would
allocate the remaining increment of water use to projects which best
meet city goals, rather than providing additional water service
strictly on a first-come, first-served basis. So long as water use
exceeds safe yield, the ordinance would allocate only part of any
increased supplies to new development, and the rest to reducing the
disparity between safe yield and consumption, so eventually water use
would again be within safe yield of supplies.
Time frame: Procedure in effect by May 1987
Responsible agencies: Community Development Department; Public Works
Department; City Attorney; Planning
Commission; City Council
Funding: General fund
24
The allocation system will assure that: (1) no single project can
receive a year's whole allocation for a certain use category; (2) a
project which reduces water use in existing development by at least
twice the expected water use in the propose project may proceed
independently from the allocation system.
The allocation system will take priority over and may replace any
regulations or specific -plan provisions concerning growth management.
Program 2.1 The city will adopt and enforce standards for water -use efficiency in
fixtures and appliances in new and remodeled buildings. The standards
will at least equal those of the state of California and will reflect
best prevailing designs.
Time frame: Continuing
Responsible agencies: Community Development Department; Public Works
Department; City Council
Funding: General fund
Program 2.2 The city will develop and apply landscape planting and irrigation
guidelines for frugal water use. The guidelines will incorporate
local climate and soils conditions and the availability of
water -saving equipment and practices and native and naturalized
plants.
Time frame: Guidelines available by January 1988
Responsible agencies: Community Development Department; Public Works
Department; Architectural Review Commission
Funding: General fund
Program 2.3 The city will continue to establish specific conservation objectives
and activities related to water availability and use in the annual
water operations plan. When projected annual water use increases as a
percentage of water available in reservoirs, progressively more
effective water conserving measures will be implemented. Likely
activities during the 1985 - 1990 period include: monitoring
landscape irrigation for runoff, with penalties for waste;
retrofitting existing buildings with water -saving fixtures; water -use
audits and mandatory conservation plans for major water users; water
rate changes.
Time frame: Continuing
Responsible agencies: Community Development Department; Public Works
Department; City Council
Funding: General fund
23
f�
2. Water Use and Conservation
Policy 2.1 Water will be used as efficiently as is practical. [Conservation: 2.7]
Policy 2.2 The city will manage water demand to assure that it can continue to
provide a high level of water service. Controlling the number and
type of new customers through land -development review is the long-term
aspect of this management. The short-term aspect is controlling water
use by existing customers through the operational plan, which responds
to current demand and reservoir conditions.
Policy 2.3 The city will not allow land development to cause total city water use
to exceed the safe annual yield by a factor which would lead to an
unacceptable level of risk that the city could not provide adequate
water service. This assessment of risk and service will consider
water use factors and trends, reservoir status, and the likely
availability of supplemental water. Total city water use (including
Cuesta College use of Whale Rock Water) should_ not exceed the total
safe yield by more than 13 percent. When total water use exceeds safe
yield by ten to 13 percent, the full safe yield of any supplemental
sources obtained will be allocated to reducing the amount by which
current use exceeds safe yield. When total water use exceeds safe
yield by less than ten percent, one-half the safe yield of any
supplemental supplies obtained will be allocated to support additional
development and one-half will be allocated to reducing the amount by
which current use exceeds safe yield.
In long-term planning for supplemental water supplies, projected water
use should not exceed safe yield.
Program 2.4 (Figure 7) translates these policies into specific
criteria for deciding, on a yearly basis, what controls should be
placed on development in order to manage water demand.
Policy 2.4 When building entitlements must be limited to avoid excessive
increases in water use, water supply should -be allocated to new
development according a system which provides for balanced growth
consistent with other general plan elements and adopted policies. The
allocation system will establish : an acceptable annual increment of
growth in water demand; the proportion of acceptable water -demand
growth which will be available to each land -use category; a ranking
system which, within each category, gives highest priority to those
projects which best meet general plan objectives. Except for the
guidance of this policy, the proportions of water -demand growth
available to various land -use categories and the criteria for ranking
projects may be adjusted annually.
The system will allocate water to categories such as residential,
commercial, and government and public. Residential uses will be
allocated at least 66 percent of total water capacity to be
allocated. Within the residential category, projects affordable to
low- or moderate -income households will have highest priority.
[Housing: page 49, item 28]
22
Policy 1.8 The city will not annex an area unless the safe annual yield of
available citywide water supplies at least equals estimated water
requirements for all development, consistent with the Land Use
Element, within the city including the annexed area. The only
exceptions to this policy are:
A. Areas which have prior agreements for water service.
B. Minor infill parcels within areas which have prior agreements for
water service, as provided in policy 1.3.
C. Areas which provide their own water, as provided in policy 3.4.
[Land Use: 9, 2I, 30]
Program 1.1 The city will update this element's service area description and
population projections as needed and in concert with any amendments to
the Land Use Element.
Time frame: continuing
Responsible parties: Community Development Department; Planning
Commission, City Council.
Funding: City general fund
Program 1.2 The city will refine this element's projections of water requirements
on the basis of water use by specific land use categories and the
likely development of those categories as provided in the Land Use
Element.
Time frame: Following adoption of the Land Use Element update
(tentatively, by 1989).
Responsible parties: Community Development Department; Public Works
Department; Planning Commission; City Council.
Funding: City general fund.
21
Policy 1.5 The city should not provide nor permit delivery of city water service
to areas beyond reliable gravity -flow or pressure systems maintained
by the city (elevations vary depending on location). [Land Use: 1.1]
Policy 1.6 Special districts or water companies should not provide water service
within the city's planning area (the San Luis Obispo Creek watershed
above Davenport Creek) to uses inconsistent with the city's general
plan. [Land Use: 8 - 11 ]
Policy 1.7 The city's water sources and treatment, storage, and distribution
systems must be able to support population and related service demands
consistent with general -plan objectives. These basic objectives are
stated in the Land Use Element (growth management) and in the Housing
Element. [Land Use: 8, 19 item 3; Housing: 7, 8, 14, 41 (item 1), 45
(item 2), 49 - 50]
The city will pursue sources of supplemental water to serve the land
use and rates of growth outlined in the general plan, with a
reasonable margin for error in projections. The city shall, by
separate agreement, provide Cuesta College with an annual supply of
water consistent with the availability of existing sources.
A. Nonresidential development.
Water demands of nonresidential development are included in the
estimated demands of residential development (population). In aiming
for (1) a closer balance between jobs or college enrollment and
housing and (2) minimum growth inducement, the city does not
anticipate or support substantial increases in nonresidential uses in
relation to residential uses. However, to more accurately estimate
potential water demands as this element is updated, the city will
prepare water -use estimates based on specific residential and
nonresidential land -use categories and the areas allocated to those
uses on the Land Use Element map.
B. Residential development
Until more detailed estimates of water requirements for land -use
categories are prepared, projections of citywide water requirements
will be based on the residential capacity and maximum population
growth rates of the Land Use Element, and the expected average water
use per resident. The following population projection is consistent
with the Land Use Element policies:
Year City Population (January of indicated year)
1985
37,400
(state estimate)
1990
41,300
1995
43,400
2000
45,600
(approximate maximum 1986 city limits capacity)
2005
47,900
2010
50,400
2015
53,000
(approximate urban reserve capacity)
(See Figure 6 for a corresponding projection of water demand.)
20
GOAL, POLICIES, and PROGRAMS
A goal is a desirable condition which the city will attempt to reach or maintain
over the long term. This element looks ahead about 30 years in assessing water
conditions and proposing programs.
San Luis Obispo's water goal is to provide a sufficient quantity of
appropriate -quality water for the needs of the community.
Policies are statements of city intent. They guide actions and decisions. A
program is a definite course of action to be carried out by certain people or
agencies within a specific time, often with a funding commitment.
San Luis Obispo's policies and programs regarding water supply and delivery are the
following. (References in brackets key to pages of other general plan elements
where parallel or related statements are found.)
1. Service Area IMA Population
Policy 1.1 The current water -delivery service area is the incorporated area of
the city. The city shall provide water service adequate for existing
uses and new development pursuant to the Land Use Element for all
areas within the city limits. [Land Use: 9, map]
Policy 1.2 The urban reserve line (the outer limit to urban development) includes
areas which the city may annex in the future. Water service adequate
for potential uses allowed by the Land Use Element (including hillside
planning provisions) shall be provided for all areas within the urban
reserve line. [Land Use: 9, 11, 19 - 35, map]
Policy 1.3 To receive city water service, areas must be annexed to the city. The
city will not provide water service for areas outside the city limit,
except for:
Customers which have prior agreements.
Uses which are consistent with the general plan and which are located
on areas of less than one acre, which are surrounded on at least three
sides by areas that are already served.
Policy 1.4 The city will not provide water service to areas outside the urban
reserve line, except as it may decide to share Whale Rock water
supplies with Cuesta College. (The city should, however, cooperate
with other agencies in developing water resources and regional water
distribution systems. Agencies with which the city may cooperate
include the San Luis Obispo County Flood Control and Water
Conservation District; Cal Poly, Cuesta Community College, California
Men's Colony, and other cities.) [Land Use: 9, I1]
19
Expand Salinas Reservoir
The city has explored three ways to raise the Salinas Dam spillway so the reservoir
could store and yield more water. If water -rights, earthquake -safety, and
environmental issues can be resolved, the expanded reservoir could yield an
additional 450 to 1,300 acre-feet per year.
New Reservoirs
New reservoirs could be built on streams within the county, such as Santa Rita Creek
west of Templeton, or on the Salinas River between the existing Salinas Reservoir
and Atascadero (Cantera Reservoir). The city and other agencies participating in
the project would have to obtain water rights. Engineers have estimated that a new
Santa Rita reservoir could yield from 3,000 to 6,000 acre-feet per year, while a
Cantera reservoir could yield about 4,600 acre-feet per year.*
Nacimiento Reservoir
San Luis Obispo County has an entitlement to 17,500 acre-feet of water from
Nacimiento Reservoir, which is owned by Monterey County. If San Luis Obispo helped
pay for a delivery system to bring water to the city, it could have some of this
water.'
State Water Project
San Luis Obispo County has an entitlement to 25,000 acre-feet of water from the
State Aqeuduct. The State Aqueduct brings water from the northern and central
Sierras to the San Joaquin Valley and Southern California. If the county decides to
obtain its entitlement, the Coastal Branch of the aqueduct would be built from the
west side of the San Joaquin Valley to northern Santa Barbara County, with branches
to serve communities in San Luis Obispo County.'
Desalination
In 1972, the United States Department of the Interior prepared a draft envrionmental
impact statement for a desalting project at the Diablo Canyon nuclear power plant.
The project was not pursued because it did not appear to be an economical source,
and the federal and state governments did not support a subsidized demonstration
project.
Preventing siltation
If the city prevented silt from reducing the yields of existing reservoirs, the need
for additional water could be reduced accordingly. Siltation can be prevented by
providing erosion -control planting and by minimizing disturbances to natural
vegetation (due to fire, road building, or excessive livestock grazing). Also,
small dams can be built on tributary streams to catch sediment before it enters the
reservoir. The silt must then be removed from the catch basins. Silt can be
dredged from reservoirs. Preliminary studies indicate that silt dams and dredging
are less cost-effective than developing some of the new sources which have been
considered.
• The city has tentatively requested 3,000 acre-feet from a regional water
project, which would include one or more of these sources: Nacimiento, the
State Water Project, or new reservoirs within the county.
17
Wastewater Reclamation
Much water used by the city carries diluted wastes to the sewage (wastewater)
treatment plant, where most harmful substances and bacteria are removed before the
water is released into San Luis Obispo Creek. With more thorough treatment and a
new piping system, the water could be used for landscape irrigation, providing up to
270 acre-feet per year. So far, the estimated costs of adequately treating and
transporting the wastewater have significantly exceeded the estimated costs of other
sources. Also, the wastewater flow helps maintain water levels in the creek, and
therefore wildlife habitat and groundwater levels for areas downstream.
Groundwater
San Luis Obispo used wells until the 1950's, when they were abandoned because
reservoir water was of better quality and more reliable. A few private wells are
used within the city, and several wells provide water for crops, houses, and
businesses in the surrounding area. However, some areas near the city have
groundwater that is unreliable or of such poor quality that it cannot be used even
for landscaping. More study is needed for a complete, accurate assessment of
groundwater feasibility, but it appears that groundwater will not make a
significant, economical contribution to the city's water needs, in comparison with
potential surface water sources. The city may install a well at the municipal golf
course, which may be used to irrigate the golf course, junior high school grounds,
and Laguna Lake Park.
If such an experiment is successful, the well water might be added to the city
system during a drought and wells may be installed at other parks. Such wells might
provide the 50 acre-feet per year used to irrigate the golf course, though yields
have not been determined. Other wells in the locations of previously used city
wells might yield additional water.
In 1942, the last full year of production, city wells yielded 1,164 acre-feet.
Historical yield may not be an accurate basis for estimating current potential
yields, which may be lower or higher. The historical yield may not indicate
quantities available during a severe drought, when all sources would be most
strained. Also, groundwater would have to meet today's quality standards.
Small Streams
The city used to draw water from springs and a small reservoir where Highway 101
approaches Cuesta Grade. The city stopped using the streams because major
reservoirs became available and the city did not want to provide the required
treatment for the small sources, which was not as cost-effective as a single large
treatment plant. The springs and streams might provide 300 acre-feet per year.
Several small streams along the Whale Rock transmission line carry storm flows to
the ocean relatively quickly and directly. It may be possible to intercept some of
these flows with temporary dams, which would not significantly damage the wildlife
habitat, and use the water by way of the existing Whale Rock system. The
feasibility of this source is being evaluated.
16
Appendix B, expanding the information summarized in Table 1, provides estimates of
water -use reductions needed during droughts likely to occur at certain intervals.
Appendix B shows year -by -year reductions, assuming that the most effective
water -saving efforts will not be undertaken until the community has experienced two
years of below-average rainfall.
Potential Water Sources
The city has considered many potential sources for more water, summarized below.
Some may be pursued as permanent additions to regular city supply, while others may
be used only in a severe drought. The city will continue to investigate the sources
described below and to look for other sources.
Conservation.
Eliminating waste and using water more efficiently postpone the need for additional
water and reduce the amount which will be needed. In the effort to balance
requirements and supply, permanently reducing use from recently accepted patterns
by a given amount is just as effective as getting that amount from a new source.
(Using low -flow toilets in new buildings or native shrubs rather than lawns around
new houses are examples of this type of conservation.) This type of conservation
can be seen as a'source of supply. Temporary reductions from typical use, as may be
achieved during a drought, are not equivalent to actually expanding supply (example:
not watering a lawn.) Generally, substantial permanent reductions from previous use
make it harder to achieve substantial temporary reductions, since the tempoary
reductions cut closer and closer to the essential and efficient use levels.
Without major changes in water -use patterns, the city could probably increase water
use efficiency by about five percent, saving about 400 acre-feet per year.
Substantial changes in water -use patterns, as might be expected during a prolonged
drought, could reduce water use by as much as 30 percent, for a savings of about
2,500 acre-feet per year. However, doing so would cause considerable inconvenience
and would be difficult to sustain."
Cooperative Use
"Cooperative use" means drawing water first from Salinas Reservoir and using Whale
Rock as a back-up source as much as possible. Salinas fills more quickly than Whale
Rock from a given amount of rainfall, and water tends to evaporate more quickly from
Salinas. Therefore, drawing water first from Salinas reduces evaporation losses and
spills and makes more room for expected runoff each winter. The city already does
this to some extent. For the city to count on water availability from this
approach, the other Whale Rock users must agree that if San Luis Obispo does not use
all of its Whale Rock entitlement one year, the city could carry-over some of the
excess and use it in following years. Doing so could increase the total safe annual
yield available to the city by 300 to 800 acre-feet.
Conjunctive Use
"Conjunctive Use" is similar to cooperative use, except water from Salinas Reservoir
would be spread to soak into the ground in areas where the city could be pump it out
when needed. Or, the city could provide excess reservoir water for farmers in
exchange for their agreeing to let the city pump groundwater in dry years.
15