HomeMy WebLinkAbout07/12/2001, 2 - WATER MANAGEMENT ELEMENT POLICIES council Mwin,D�
July 12 2001
j acEnaa Report
CITY OF SAN LU I S OBISPO
FROM: John Moss, Utilities Direct
Prepared By: Gary W. Henderson, Water Division Manager Gey✓
SUBJECT: WATER MANAGEMENT ELEMENT POLICIES
CAO RECOMMENDATION
1. Provide direction to staff relative to potential modifications to policies contained in the Water
Management Element of the General Plan.
2. If modifications are desired, direct staff to initiate the process necessary to modify the
policies in the Water Management Element.
REPORT-IN-BRIEF
During the five year update process for the City's Urban Water Management Plan (UWMP) in
April of 2001, Council directed staff to return for discussion of policies contained in Chapter 2 of
the document. The policies in Chapter 2 of the UWMP:are adopted as the Water Management
Element to the General Plan. The amendment of the policies will require public hearings before
the Planning Commission and the City Council.
The four policies that are discussed in detail in the following sections of this report for potential
reconsideration or modification are listed below:
4.1.1 Reliability Reserve
8.1.2 Supplying New Development
8.1.3 Reserve for Intensification and Infill Development
8.1.4 Accounting for Reclaimed Water
The policies have received thorough discussion over the years and have been modified based on
new information or issues. As the City continues to grow and new water resources are pursued,
the Council needs to continue to review the policies in the Water Management Element to insure
that they provide the framework necessary to ensure adequate water resources for the City.
DISCUSSION
On April 24, 2001, the City Council adopted an update to the Urban Water Management Plan
(UWMP) which is required by the State every five years.. Chapter 2 of the UWMP contains the
policies relative to water which are adopted as the Water Management Element to the City's
General Plan. The update of the UWMP did not propose any revisions to the policies in Chapter
2 but did identify four policies that should be considered by Council for potential modification.
Revisions to the policies require an amendment to the Water Management Element (WME) of
the General Plan which will require public hearings before the Planning Commission as well as
the City Council.
Council Agenda Report—Water Management Element Policies
Page 2
During Council discussions relative to the UWMP, Council agreed with staff and requested that
staff return for a discussion of certain policies within the WME to determine if there is an interest
among a majority of the Council members to reconsider and/or revise the policies. In addition,
there are several policies that staff feel warrant a more detailed discussion to fully understand the
long term ramifications of the policies. Listed below are all of the policy sections in the WME.
The policy sections that Council has indicated an interest in revising are highlighted and
discussed in more detail in the following sections of this report. The Water Section of the
General Plan Water & Wastewater Management Element is included as Attachment 1 to this
report. Council is requested to thoroughly review this attachment, and in particular the basis of
all policies, to provide a solid framework for understanding the context and interrelationship of
the policies.
Water Management Element Policies
1.0 Safe Annual Yield 7.0 Multi-source Water Supply
1.1.1 Basis of Planning 7.1.1 Multi-source Water Supply
1.1.2 Safe Annual Yield
1.1.3 Groundwater 8.0 Allocation of New Water Supplies
8.1.1 Balancing Safe Yield and Overall
2.0 Water Conservation Demand
2.1.1 Long-term Water Efficiency 8.1.2 Supplying New Development
2.1.2 Short-term Water Efficiency 8.1.3 Reserve for Intensification and
1, Infill Development��
3.0 Water Demand Projections 8.1.4 Accounting for Reclaimed d a rWa rW
3.1.1 Basis of Projections 8.1.5 Private Water Supplies
3.1.2 Water Use Rate
3.1.3 Overall Projected Demand 9.0 Water Allocations and Offsets
3.1.4 Present Water Demand 9.1.1 Exemptions for Offsets
9.1.2 Basis for Allocations and Offsets
4.0 Reliability Reserve
4.1 1 Reliability Reserye 10.0 Reclaimed Water
10.1.1 Reclaimed Water Quality
5.0 Siltation at Salinas and Whale Rock 10.1.2 Uses of Reclaimed Water
Reservoirs
5.1.1 Accounting for Siltation 11.0 Water Service within the City
11.1.1 Water Service within the City
6.0 Supplemental Water Requirements
6.1.1 Supplemental Water Requirement
6.1.2 Supplemental Water Sources
6.1.3 Paying for Supplemental Water
for New Development
As previously mentioned, the highlighted policies above are those that Council members have
expressed an interest in discussing and that staff feels should again receive a thorough discussion
by the City Council. In the following discussion, the complete policy wording will be listed in
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italics at the beginning of each section and a discussion of the basis and possible issues for
consideration will be presented to facilitate Council discussion.
4.0 Reliability Reserve
4.1.1 Reliability Reserve: In seeking and accounting for new water supplies, the City
will strive for a "reliability reserve" of 2,000 acre-feet safe annual yield (about 20
percent of projected future water demand at full build-out).
The concept for developing a"reliability reserve".was adopted by the.City Council following the
drought period of 1986-1991. This reserve is intended to provide adequate water supplies during
unpredictable changes such as a new worst case drought, loss of one of the City's water sources,
contamination of a source or other emergency conditions. When the reliability reserve is
developed, it can not be used to allow additional development. The City voters added this
provision relative to the use of the reliability reserve (once established) to the City.Charter in
1996.
At this time, no water has been committed to the "reliability reserve". The policies in Section 8.0
state that half of the safe annual yield from a new water supply project will be allocated to the
reliability reserve. As the City moves toward completion of the Water Reuse Project, and thus
the implementation of a new water supply project and commitment of yield to the reserve, this
policy should again receive a thorough discussion by the City Council to evaluate the potential
costs and implications of what is essentially an "insurance policy". When this policy was
originally adopted the water supply projects being pursued had estimated costs on the order of
$400-500 per acre foot. With the current costs for Water Reuse, Nacimiento and Salinas
Reservoir projected to exceed $1,000 per acre foot. The 2,000 acre foot reliability reserve will
have an annual cost in excess of$2 million dollars.
The reliability reserve will Table 1: ReliabilityReserve App ortionment
serve both existing water
Population Portion of Percent
customers and new
development areas. The Reliability of Total
costs will be shared - --- Reserve
Existing users* 43,415 1,551 77.5%
proportionally between
existing customers and new New development 12,585 449 22.5%
development. Table 1 shows I Total 56 000 2 000 100.00n/o
the relationship between * 1993 population
existing and new development at the time the policy was established.
As indicated, the largest portion of the costs will therefore be attributable to existing customers
and will be paid through water rates. Council's consideration of this policy at this time is
important based on the likely accomplishment of the Water Reuse Project in the next several
years and the high costs of all the supplemental water supply projects currently under
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Council Agenda Report—Water Management Element Policies
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consideration. In addition, the reliability reserve represents over 50% of the additional water
needs projected for the City (as shown
Table 2: Water Supply.Re uirements (acre feet) in Table 2), which will need to be
Additional Water to Serve Build-out 1,556 acquired from new water supply
ReliabilityReserve 2,000 projects such as Water Reuse,
Siltation (2001 to 2025) 240 Nacimiento or Salinas Reservoir
Total Water Supply Requirement 3,806 Expansion Project. Staff is not
recommending elimination of the
reserve, however does recommend Council discuss and consider the policy and its fiscal and
environmental implications prior to commitment of any yield to the reserve.
8.0 Allocation of New Water Supplies
Section 8.1.2 provides the policies relative to water availability for new development. Sections
B. and C. of this policy are discussed separately in the following sections.
8.1.2.E Supplying New Development. Any safe annual yield from new water supply
projects beyond that needed to balance safe annual yield and present demand will be
allocated (A) one-half to the reliability reserve and compensating for reduced yields due to
siltation and (B) one-half to development, subject to the requirements in Policy 8.1.3,
"Reserve for Intensification and Infill."
As discussed earlier in this report, the establishment and dedication of water to the reliability
reserve can have significant fiscal impacts and may also have associated environmental impacts
that the Council may wish to consider when new water supply projects are initiated. It may also
constrain our ability to control land uses within our urban reserve line, if properties develop in
the County due to inadequate supplies for new development. In addition, this policy should be
revised based on previous Council revisions to the policies relative to accounting for siltation in
the reservoirs. The current policy accounts for siltation each year by reducing the safe annual
yield (Policies 1.1.2 & 5.1.1) that is available to the City which reduces the water available to
allocate to new development. Based on this method for accounting for losses due to siltation, the
above policy should delete the following from the policy staterhentt "...and compensating for
reduced yields due to siltation..." since this is now being done on an annual basis.
8.1.2.0 Supplying New Development. Until a determination is made by the City Council
that essentially all toilet and showerhead fixtures in the City are replaced with low flow
toilet and showerhead fixtures, projects may be built if the developer makes changes, in
facilities served by the City, which will reduce long-term water usage equal to twice the
water allocation required for the project.
The requirement to retrofit existing facilities as a condition of new development was initiated in
the late 1980's at a time when the City was actually exceeding the safe annual yield available
from our water resources. Since the City was exceeding the available water supplies, the only
way for new development to acquire a water allocation was through the retrofit program.
Following the end of the drought in 1991 and during the development of the Urban Water /�
Council Agenda Report Water Management.Element Policies
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Management Plan, the City adopted a planning figure of 145 gallons per person per day(gppd) as
the basis for identifying water available for allocation. This lower figure would indicate that
there was water available for new development without requiring retrofit of existing facilities.
Since the program had been very effective and was achieving the goals of retrofitting existing
facilities and thereby extending the City's water resources, Council modified the policy to require
retrofitting "until a determination is made by the City Council that essentially all toilet and
showerheads" are replaced.
The Water Use Offset Program (retrofit to build) has provided about 65% of the retrofit
accomplished throughout the City to date. The City also has the Retrofit Rebate Program and the
Retrofit Upon Sale Program, that have accounted for the remainder of the retrofits accomplished
to date. Staff estimates that there are approximately 39,000 toilets in the City. As of April 12,
2001, approximately 28,500 toilets have been retrofit leaving around 10,500 toilets left for
replacement. The majority of the remaining toilets are in single family residences. With the City
approximately 73% retrofit, it is becoming increasingly difficult to locate willing property
owners to allow their facilities to be retrofitted. In addition, with the current number of
development projects currently in the "pipeline", there may not be sufficient toilets remaining to
retrofit to provide the required 2 to 1 offset,even if all properties agreed to allow the retrofit.
While retrofit contractors have been canvassing the community with mailings and making direct
contacts with property owners, interest in the program is continuing to decline. There appears to
be a large number of the remaining properties that do not want their toilets retrofit for a number
of reasons. Staff would request-that the Council consider modifications to the program in light of
these issues.
There are several options that Council could consider to alleviate the pending problems. The
first would be to eliminate the requirement to retrofit as a condition of issuance of a building
permit (i.e. consider the City "essentially" retrofit in terms of the Water Use Offset Program).
Developers would be required to pay the full water impact fee prior to issuance of a building
permit. Under the current program, the water impact fee is reduced.by $150 or $300 per toilet
retrofit depending on type. Since the actual city-wide water use rate has been stabilizing at
around 130 gallons per person per day and the basis of available water for allocation is 145 gppd,
there is a safety margin to insure that there are not additional impacts to existing customers due
to new development. In addition, with the requirement for retrofit upon sale, an ongoing retrofit
rebate and the fact that the only low flow toilets are allowed to be sold in California, the
remainder of the retrofit will occur over time, albeit at a slower rate.
Another option would be to require all private properties to be retrofit or face a penalty or
surcharge on their water bill. This has been considered in a few areas in southern California but
would likely be viewed as a "heavy handed" approach by the City and may not be deemed
necessary since there are other programs in place that will insure that the City is retrofit in the
future.
Staff would request that Council provide direction concerning specific modifications that may be
deemed appropriate to alleviate the problems that are discussed above. The problems will only
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Council Agenda Report—Water Management Element Policies
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grow more difficult as time goes on due to fewer locations that are available or willing to be
retrofit. If the Council determines that the program should be phased out, staff would-
recommend
ould_recommend establishing a sunset date for the program at this time. A reasonable phase-out
timeframe would be October 1, 2001.
8.1.3 Reserve for Intensification and Infill Development: The City will annually update the
water available for allocation based on the difference between the adopted safe annual yield
(policy 1.1.2) and the present water demand (policy 3.1.4) as part of the annual Water
Resources Status Report. One-half of the water available for allocation (not to exceed the
total required for infill and intensification), as identified in the Water Resources Status
Report, will be reserved to serve intensification and infill development within existing city
limits as of July 1994.
The policy for reserving water for infill and intensification was originally part of the 1977 Land
Use Element and was further discussed in the early 1990s during development of the Urban
Water Management Plan. The policy as included in the original Urban Water Management Plan
required reserve of the full amount of water needed to serve intensification and infill within the
existing city limits as of July 1994.
In July of 1996, the Council modified this policy to allow half of the water available for
allocation to be used for new annexation areas and the other half to be reserved for infill and
intensification. One of the original concerns relative to the adoption of the reserve policy was
that new annexations would quickly use up the available water and infill projects would not be
able to be built. What has actually occurred, is that the majority of the development since 1994
has occurred in areas already within the existing city limits, in particular the Edna-Islay area.
Another area which received discussion relative to modification of the policy in 1996 was the
fact that full intensification and infill of all properties may not occur for many years (recent
experience shows that infill development is easier said than done). Reserve of water for
properties that may not ever fully develop may conflict with the goals of the City's General Plan
by constraining our ability to control land within our urban reserve line. In addition, it was noted
that the undeveloped properties have not paid water impact fees to secure any rights for water to
serve the property. These were some of the issues raised by Council during the deliberations on
the policy modification relative to reserve for infill and intensification which Council may
consider relative to potential revisions to this policy. Council could consider reserving "a
different split" of water for infill and intensification or eliminate the policy and allocate water to
development as it occurs.
8.1.4 Accounting for Reclaimed Water. Reclaimed water will be added to the City's safe
annual yield consistent with policies contained within this document for other water supply
projects.
The Water Reuse Project is continuing to move forward and will likely be the first new water
supply to be added to the City's other available water sources. The total potential yield from the
Water Reuse Project is estimated to be 1,200 acre feet per year. It is currently estimated that
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Council Agenda Report—Water Management Element Policies
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following completion of the reclaimed water distribution system, the initial water use offset will
be 113 acre feet per year. As new development occurs or exchanges of reclaimed water for
groundwater are accomplished, the amount of reclaimed water use will increase over time.
The current policies in the Water Management Element would treat the Water Reuse Project like
any other new water supply project. This would mean that 600 acre feet would be added to the
reliability reserve and 600 acre feet would be available for allocation following project initiation.
Based on the estimated amount of reclaimed water that will be used immediately following
construction, staff would recommend Council direction for potential modification of the policy.
Staff would suggest that the maximum amount of water available for allocation should not
initially be 600 acre feet but only the amount projected to be used or offset (i.e. 113 initially),
increasing to 600 acre feet per year as additional offsetting uses are brought on-line. This change
in policy relative to reclaimed water will insure that new development does not exceed the City's
available water resources. If consistent with previously discussed policies relative to the
reliability reserve, 600 acre feet per year should be immediately committed to the reserve upon
initiation of the project.
Summary
The policies contained within the Water Management Element to the General Plan have received
thorough discussion over the years and have been modified based on new information or issues.
As the City continues to grow and new water resources are pursued, the Council needs to
continue to review the policies to insure that they provide the framework necessary to insure
adequate water resources for the City. Since the policies are an Element to the General Plan, any
policies that the Council wishes to reconsider, with the possible exception of phasing out the
Water Use Offset Program, will require public hearings before the Planning Commission prior to
Council consideration. Staff requests Council provide general direction on these and any other
WME policies where change is desired. Staff will then begin the process of seeking the change
to the Water Management Element of the General Plan. Council may also wish to request
additional analysis and discussion of these or other policies and may direct staff to prepare and
return with that additional analysis.
FISCAL IMPACT
There are no fiscal impacts directly associated with this report. The establishment of the
reliability reserve, as discussed earlier in this report, could have significant impacts depending on
the source of water for the reserve as well as the cost for water from that source. Elimination of
the retrofit offset program could also result in increased impact fee revenues to the Water Fund.
Staff will provide a more detailed analysis of any recommended policy changes at the time those
policies are proposed to the Planning Commission and Council for approval.
ATTACHMENTS
1. Water Section of the "General Plan Water&Wastewater Management Element"
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ATTACHMENT 1
City of SLO General Plan Water&Wastewater Management Element
INTRODUCTION
The City's General Plan guides the use and protection of various resources to meet community
purposes. It reflects consensus and compromise among a wide diversity of citizens' preferences,
within a framework set by State law. The General Plan contains elements that address various
topics.
The City decided to adopt an element addressing water resources and wastewater treatment because
of the vital role of these resources and the far-reaching impacts of water policies on community
growth and character. This element translates the Land Use Element's capacity for development into
potential demand for water supply and wastewater treatment. This element outlines how the City
plans to provide adequate water and wastewater services for its citizens, consistent with the goals
and policies of other General Plan elements.
Before adopting or revising any General Plan element, the Planning Commission and the City
Council must hold public hearings. The City publishes notices in the local newspaper to let citizens
know about the hearings at least ten days before they are held. Also,the City prepares environmental
documents to help citizens understand the expected consequences of its planning policies before the
hearings are held.
Anyone may suggest or apply for amendments to General Plan elements. The City will probably
update this element about every five years,or more frequently if necessary.
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ATTACHMENT 1
City of SLO General Plan_ Water&Wastewater Management Element
WATER SECTION
1.0 SAFE ANNUAL YIELD
1.1 POLICIES
1.1.1 Basis for Planning
The City will plan for future development and for water supplies based on the amount of water
which can be supplied each year,under critical drought conditions. This amount,called"safe annual
yield,"will be formally adopted by the Council. The safe annual yield determination will be revised
as significant new information becomes available, and as water sources are gained or lost. The
determination will consider a staff analysis,which will recommend an amount based on coordinated
use of all water sources. Each change to safe annual yield will be reflected in an amendment of this
Plan.
1.1.2 Safe Yield Amount
The City's safe annual yield,from the coordinated operation of Salinas and Whale Rock reservoirs
and 500 acre feet of groundwater,is shown in Table 1. The safe annual yield includes reductions due
to siltation at the reservoirs, discussed in more detail in Section 5.0.
1.1:3 Groundwater
A. The amount of groundwater which the City will rely upon towards safe annual yield is
identified in policy 1.1.2. The City will maximize the use of groundwater in conjunction
with other available water supplies to maximize the yield and long-term reliability of all
water resources and to minimize overall costs for meeting urban water demands. The City
shall monitor water levels at the well sites to determine whether reduction or cessation of
pumping is appropriate when water levels approach historic low levels.
B. The City will not compete with local agricultural use of groundwater outside the urban
reserve line or damage wildlife habitat through reduced natural stream flows in obtaining
long-term sources of water supply.
BACKGROUND
Safe annual yield is the amount of water that can reliably be produced by the City's water supply to
meet the water demand. It is estimated by simulating the operation of the City's water supply sources
over an historical period to determine the maximum level of demand that could be met during the
most severe drought for which records are available.
The safe annual yield of an individual source of water supply is defined as the quantity of water
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City of SLO General Plan Water&Wastewater Management Element
which can be withdrawn every year,under critical drought conditions. Safe annual yield analyses of
water supply sources are based on rainfall, evaporation and stream flow experienced during an
historical period. The City of San Luis Obispo uses a period beginning in 1943, which covers
drought periods in 1946-51, 1959-61, 1976-77,and 1986-91. The historical period used in the latest
computer analysis to determine safe annual yield extends from 1943 through 1991 and includes the
most recent drought. Although future conditions are unlikely to occur in the precise sequence and
magnitudes as have occurred historically, this technique provides a reliable estimate of the future
water supply capability of the existing sources,since the long term historical record is considered a
good indicator of future conditions.
The safe annual yield gradually declines as silt accumulates in the reservoirs, thereby reducing
storage capacity (discussed in more detail on page 10).
Prior to 1991,the"controlling drought period"for determining safe annual yield was 1946 to 1951.
The critical period for determining safe annual yield from the two reservoirs is now the period from
1986 to 1991. The safe annual yield is reflected in the table below and includes losses_ associated
with siltation.
TABLE 1
SAFE ANNUAL YIELD
Year Salinas&Whale Groundwater Total
Rock Reservoirs
2000 7,040 acre feet 500 acre feet 7,540 acre feet
2001 7,030 acre feet 500 acre feet 7,530 acre feet
2002 7,020 acre feet 500 acre_feet 7,520 acre feet
2003 7,010 acre feet 500 acre feet 7,510 acre feet
2004 7,000 acre feet 500 acre feet 7,500 acre feet
2005 6,990 acre feet 5.00 acre feet 7,490 acre feet
2006 6,980 acre feet 500 acre feet 7,480 acre feet
2007 6,970 acre feet 500 acre feet 7,470 acre feet
2008 6,960 acre feet 500 acre feet 7,460 acre feet
2009 6,950 acre feet 500 acre feet 7,450 acre feet
Previous Safe Annual Yield Studies
Previous studies of the critical historical drought periods at Salinas and Whale Rock reservoirs have
indicated the following safe annual yields were available to the City:
Water Supply Safe Annual Yield Reference
Salinas Reservoir 4,800 acre-feet Corps of Engineers, 1977
Whale Rock Reservoir* 2,060 acre-feet Dept Water Resources, 1974
Coordinated Operation 500 acre-feet CH2M-Hill, 1985
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ATTACHMENT 1
City of SLO General Plan Water&Wastewater Management Element
Groundwater 500 acre-feet Water Operational Plan, 1993
TOTAL 7,860 acre-feet
*City's share of Whale Rock Reservoir safe annual yield.
Past safe annual yield analyses for the two reservoirs assumed independent operation and historical
data to the date of each report. The critical drought period for the previous studies was 1946-51.
The studies also assumed a minimum pool at Salinas and Whale Rock of 400 and 500 acre-feet
respectively. "Coordinated operation"is a concerted effortto operate the two reservoirs together for
maximum yield. Since Salinas Reservoir spills more often than Whale Rock Reservoir, due to its
larger drainage area and more favorable runoff characteristics,and has higher evaporation rates,the
combined yield from the two reservoirs can be increased by first using Salinas to meet the City's
demand and then using Whale Rock as a backup source during periods when Salinas is below
minimum pool or unable to meet all of the demand. The 500 acre-feet increase in safe annual yield
was a preliminary estimate of the additional yield attributed to coordinated operations of the
reservoirs identified in the 1985 report prepared by CH2M-Hill.
In 1988, the City contracted with the engineering firm of Leedshill-Herkenhoff, Inc., to prepare a
detailed analysis of the City's water supplies and safe annual yield,based on coordinated operation of
the reservoirs. The report "Coordinated Operations Study for Salinas and Whale Rock reservoirs"
was completed in 1989. The study estimated total safe annual yield for the City from the two
reservoirs to be 9,080 acre-feet per year. Since the study period was only to 1988 and the City was in
a drought period of unknown length, this amount was never adopted by Council. It should be
emphasized that this estimate assumed that the "controlling drought period"was 1946 to 1951 and
that Whale Rock Reservoir is used only when Salinas is below minimum pool or can not meet the
monthly City demand, and does not consider limitations on the use of Salinas water due to water
quality constraints. Following the end of the of 1986-1991 drought, staff updated the computer
program created by Leedshill-Herkenhoff to estimate the impact of the drought on safe annual yield
of the reservoirs. The analysis determined that the recent drought was the critical drought of record
for the two reservoirs and resulted in a reduction in the safe annual yield.
Groundwater Resources
The groundwater basin that underlies the City of San Luis Obispo is relatively small. Therefore,
extractions in excess of 500 acre-feet per year during extended drought periods cannot be relied
upon. Because the basin is small, it tends to fully recharge following significant rainfall periods.
Following periods of above average rainfall, the groundwater basin may be capable of sustaining
increased extraction rates to meet City water demands. Since both Salinas Reservoir and the
groundwater basin fill up and"spill"following significant rain periods,there is a benefit in drawing
from these sources first and leaving Whale Rock Reservoir as a backup supply. The conjunctive use
of the groundwater basin and surface water supplies in this manner will provide an effective
management strategy that increases the reliability of all the resources to meet current and future
water demands.
Another benefit of maximizing groundwater use is that it typically requires minimal treatment that
reduces costs compared to surface water supplies. Even with treatment for nitrates and PCE, the
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City of SLO General Plan Water&Wastewater Management Element
projected costs associated with that treatment show groundwater to be comparable to other
alternative future water supply projects.
Past City policy has been not to compete with agriculture for use of groundwater resources.
Recognizing the importance of the production of food and fiber as well as open space provided by
agricultural land outside the urban reserve line, the City will continue to endorse this policy.
2.0 WATER CONSERVATION
2.1 POLICIES
2.1.1 Long-term Water Efficiency
The City will implement water-efficiency programs which will maintain long-term,per-capita usage
at or below the per capita use rate as identified in.Policy 3.1.2.
2.1.2 Short-term Water Shortages
Short-term mandatory measures,in addition to the long-term programs,will be implemented when
the City's water supplies are projected to last three years or less based on projected water
consumption,coordinated use of all city water supply sources, and considering the drought pattern
on which safe yield is based(or response to other situations which may interrupt supply).
BACKGROUND
Water conservation was referenced as a part of the City's water management policy in 1973. In 1985;
the City adopted the Annual Water Operational Plan policy that established water conservation as a
means of extending water supplies during projected water shortages. Since 1985,. many
technological and philosophical changes have occurred which are proving water conservation to be
both a short term corrective measure for immediate water supply shortages and a long term solution
to water supply reliability.
A comprehensive evaluation of the potential water savings from current water conservation
technologies and programs is included as Appendix V to this Plan. Based on the reliability of the
water conservation measures which were evaluated, and the cost effectiveness of the proposed
programs,a long term reduction in water demand of approximately twenty percent from the average
per capita use recorded in 1986-87 is used for planning for future water conservation programs as
well as future water supply needs.
Because of the experience during the drought of 1986 to 1991,the City has developed a short term
plan to deal with immediate water shortages and has recognized the importance of water efficiency
by supporting long term programs. The City will reevaluate and update its water conservation efforts
in response to changing water demand, supplies,technology and economic conditions.
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ATTACHMENT 1
City of SLO General Plan_ Water&Wastewater Management Element
3.0 WATER DEMAND PROJECTIONS
3.1 POLICIES
3.1.1 Basis of Projections
The City will project.water requirements, considering long-term conditions and the full range of
water uses in the City.
3.1.2 Water Use Rate
The City shall use 145 gallons per person per day(this equates to approximately 0.162 acre-foot per
person per year)and the number of City residents to plan total projected future water demand. This
quantity will be revised if wan-anted by long-term water use trends, including differences in the
relationship between residential and nonresidential usage. (Throughout this Plan, 145 gallons per
person per day is used in computations of future water demand.)
3.1.3 Overall Projected Demand
Applying 145 gallons per person per day to a projected City resident population of about 56,000 at
General Plan build-out results in a projected water demand of 9,096 acre-feet per year(excluding
demand from the Cal Poly campus, which has separate entitlements).
3.1.4 Present Water Demand
Present water demand shall be calculated by multiplying the water use identified in Policy 3.1.2 by
the current city population (as determined by the California.Department of Finance, Population
Research Unit).
BACKGROUND
The City must know how much water will be needed to serve residents,businesses,and other users
to accommodate the General Plan. This quantity can be projected using different methods. All
methods involve assumptions about both future usage rates and the numbers and types of users
expected in the future. The quantity expressed in the policy above corresponds closely with both(1)
total city-wide usage compared with total resident population and(2)projections of water demand
based on usage by various land use categories. There always will be some uncertainty in estimating
development capacity (such as the number of dwellings or residents) as well as the usage per
customer type(such as acre-feet per dwelling or per resident.) The estimating method must use
reasonable assumptions,based on experience,to assure an adequate level of water supply while not
overstating demands.
Since the early 1970's,usage estimates have ranged from 0.17 to 0.22 acre-foot per resident per year
(about 155 to about 195 gallons per person per day). The estimates have varied so widely due to
actual differences in consumption over time and to confusion about accounting for Cal Poly usage..
(The City treats and delivers much of the water used by Cal Poly,even though Cal Poly has separate
entitlements.) Table 2 shows recent water usage compared with City resident population. Table 3
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compares the "per capita" and "land use" methods of estimating water needs.
TABLE 2
WATER USE 1980-1999
Water from Treat- Total City Water Population Total Gallons City Gallons
ment Plant and Wells Demand (3) per Person per, per Person
Year acre-feet(1) acre-feet (2) Day per Day
1980 6,745 6,145 34;252 176 160
1981 6,941 6,341 _ 34,759 178 163
1982 6;584 5,984 35,239 167 152
1983 6,800 6,200 35,660 169 155
1984 7,862 7,262 36,407 182 178
1985 8,025_ 7,425 37,378 193 177
1986 8,367 7,767 38,205 196 181
1987 _ 8,399 7,799 38,282 196 182
1988 8,411 .7,811 39,858 188 175_
1989 6 004 5 404 41-027 129 118
1990 4 796 4196 4l 958 102 89
1991 4 640 4 040 42178 98 86
1992 5,316 4,716 42,922 110 98
1993 5,572 4,972 43,415 115 102
1994 5,775 5,200 43,919 117 106'
1995 6,075 5,574 41,295 131 120
1996 6,379 5,742 41,404 138 125
1997 6,868 6,220 41,807 147 133
1998 6,399 5,852 42,201 135 124
1999 6,736 1 6,172 42,446 142 129_
Bold, italicized years(1989- 1991)indicate mandatory conservation period.
(1) Data from City Water Treatment Plant production reports;includes Cal Poly potable water.
(2) Cal Poly water use assumed constant for years before 1994, at 600 acre-feet.
(3) January 1 population estimates from the California Department ofFinance,Population Research Unit,as
revised through 1999.
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TABLE 3
PER CAPITA WATER USE
Method 1: Water treatment plant production and Method 2: Metered use by development type
Population and Land Use Element
Per capita water use-based on historic demand, Per capita water use-based on historic
population,and conservation demand,land use,and conservation
Annual demand 1987 year hi est use 8,397 acre-feet General Plan build-out(1992 draft)
Land use types(with 20%reduction from pre-1987
Less Cal Poly subtract 600 acre-feet 7,797 acre-feet usage rates)
from tom,based an average demand Single family residential 3,630 acre-feet
Multifamily residential 2,633
Retail commercial 422
Office 393
Per capita use Convert to gallons and 182 gauons/day Services&manufacturing 438
divided by 365. Divide by Dept.of Finance
population estimate(38,282) Motellhotel 608
Hospitals,schools,parks 1,432
Total 9,566 acre-feet
Less 20%long-term conservation 145 gallons/day Per capita use Convert to gallons 152 gallons/day
and divide by 365. Divide by estimated
56,000 buildout population(excludes
Cal Poly residents).
Based on the analysis of these two approaches and the inclusion of long term water conservation
programs, 145 gallons per day per person is used throughout this element for long term water supply
planning purposes.
TABLE 4
CALCULATION OF PRESENT (2000)WATER DEMAND
Gallons per City Gallons per Days in
person per day Population Acre Foot a Year Current Demand
1 acre-foot
145 43,027 325,851 gallons 365 6,988 acre feet
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4.0 RELIABILITY RESERVE
4.1 POLICY
4.1.1 Reliability Reserve
In seeking and accounting for new water supplies, the City will strive fora"reliability reserve" of
2,000 acre-feet safe annual yield(about 20 percent of projected future water demand at full build-
out).
BACKGROUND
The concept of"reliability reserve"for long range water planning was presented to the City Council
in 1990.At that time,the City was in the midst of an extreme drought and was considering building a
desalination plant to meet projected short term water supply deficits. This reserve is intended to
maintain adequate City water supplies during unpredictable changes such as a new worst case
drought,loss of one of the City's water sources,contamination of a source,or failure of a new source
to provide projected yield, and not to allow additional development.
Originally, California water law was created to provide certainty in water supply for individuals or
Agencies using a source. However, changing water laws now provide little certainty for planning
future supplies. Recent decisions requiring additional downstream releases for environmental
protection purposes,such as those affecting Mono Lake and the Sacramento-San Joaquin Delta,have
shown that the impacts on all users associated with water supply projects sometimes must be
addressed.
The City's water supply sources may also be jeopardized by water quality and drought conditions.
Contamination or new requirements for water treatment could reduce the available supply to the City
for an extended period. Also, current safe annual yield estimates for Salinas and Whale Rock
reservoirs are based on historical data since 1943.The recent drought of 1986-1991 is the controlling
period for safe annual yield calculations. If there is a future drought more extreme than this period,
the safe annual yield of the reservoirs will likely be reduced. These uncertainties prompted the
Council to establish a reliability reserve of 2,000 acre-feet to protect the City from water shortages in
the future (March 3, 1993, Resolution No. 8135). The reserve will not guarantee that the City will
never experience water shortages in the future,but will reduce the impacts associated with reductions
in available supplies.
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5.0 SILTATION AT SALINAS AND WHALE ROCK RESERVOIRS
5.1 POLICY
5.1.1 Accounting for Siltation
The City shall account for siltation in the adoption of the safe annual yield as identified in Policy
1.1.2. The estimated annual reduction in safe annual yield from Salinas and Whale Rock Reservoirs
is 10 acre-feet per year.
BACKGROUND
Siltation at reservoirs is a natural occurrence that can substantially reduce the storage capacity over
long periods. The reduction of available storage will reduce the safe annual yield of the reservoirs.
Siltation at reservoirs varies depending on factors such as rainfall intensity and watershed
management practices. There have been numerous reports addressing siltation at Salinas Reservoir,
but no studies have been done for Whale Rock reservoir.
Table 5 lists the studies for Salinas reservoir and the estimated storage capacities. During the recent
drought, water at Salinas reservoir fell to record low levels. Recognizing the unique opportunity
presented by the low water level, the County contracted with a local engineering consultant to
provide an aerial survey of the lake and prepare revised storage capacity information. The latest
information reveals that the survey conducted in 1975 may have over estimated the siltation rate at
the reservoir. Early studies indicated average annual siltation rates from 23 acre-feet per year to 34
acre-feet per year. The study done by the U.S.Geological Survey in 1975 estimated that the siltation
rate was approximately 82 acre-feet per year. Thelatest information indicates that the siltation rate is
on the order of 40 acre-feet per year.
Since Whale Rock is used as a backup supply for the City,it may be many years until the lake level
drops to the point where an aerial survey of siltation can be economically performed. Since no
information is available to indicate what rate of siltation is occurring at the Whale Rock reservoir,it
is assumed for planning that the annual average rate of siltation is similar to Salinas reservoir. The
reliability reserve discussed in Policy 2.4 can offset the additional long-term loss.
The safe annual yield from the two reservoirs will be continually reduced as a result of siltation.The
City's computer model can be used to calculate the reduction in safe annual yield from Salinas and
Whale Rock Reservoirs to date. The model can then be used to calculate estimated annual
reductions in the future assuming siltation occurs in an average pattern.
Since the storage capacity for Salinas reservoir was last estimated in 1990,the annual loss of 40 acre-
feet per year can be applied from that date. However, since Whale Rock reservoir's siltation has
never been factored into the total available water storage, the loss of 40 acre-feet per year would
apply to the period since the reservoir was constructed in 1961.
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TABLE 5
SALINAS RESERVOIR CAPACITY STUDIES
Total Usable Avg Annual Loss
Year Agency Capacity Capacity Usable Capacity
(acre-feet) (acre-feet) (acre-feettyear)
1941 U.S. Army 44,800 26,000 -
1947 U.S. Soil Conservation - 25,860 23.3
Service
1953 U.S. Soil Conservation
Service and U.S. Forest - 25;590 34.2
Service
1975 U.S. Geological Survey 41,400 1 23,200 82.4
1990 County of San Luis Obispo 41,791 24,035 40.1
Usable capacities are shown at the 1,301.0-foot spillway elevation because the usable capacity at the 1,300.7-
foot elevation for the 1947 and 1953 studies could not be accurately determined. Usable capacity at the
1,300.7-foot elevation for the 1941 survey was determined to be 25,800 acre-feet and for the 1975 survey was
23,000 acre-feet.
The estimated loss in storage capacity for Salinas Reservoir between 1990 and 2000 is 400 acre-feet..
The estimated loss at Whale Rock Reservoir between 1961 and 2000 is 1,560 acre-feet. Based on
these reduced storage capacities,the computer model projects a loss of 250 acre feet of safe annual
yield from the combined operation of the two lakes. With an estimated loss of 40 acre feet per year
at each reservoir, the total safe annual yield from the two lakes will be reduced by 10 acre feet per
year. This loss of yield is accounted for in the adopted safe annual yield figures shown in Table 1.
6.0 SUPPLEMENTAL WATER REQUIREMENTS
6.1 POLICIES
6.1.1 Supplemental Water Requirement
The City shall develop additional water supplies to meet the projected demand at build-out of the
City's General Plan(Table 6)and to establish the reliability reserve and to offset water yields lost due
to siltation (Table 7). The supplemental water supply amount shall be based on the adopted per
capita water use figure identified for planning purposes in policy 3.1.2.
6.1.2 Supplemental Water Sources
In deciding appropriate sources of supplemental water,the City will evaluate impacts on other users
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of the water and other environmental impacts, total and unit costs, reliability, water quality,
development time, and quantity available.
6.1.3 Paying for Supplemental Water for New Development
The cost for developing new water supplies necessary for new development will be paid by impact
fees set at a rate sufficient to cover the annual debt service cost of the new water supplies attributable
to new development.
BACKGROUND
Based on the Land Use Element adopted by the City Council in August 1994 and a per capita use
rate of 145 gallons per person per day, the projected total amount of water for the City to serve
General Plan build-out is 9,096 acre-feet. Table 7 shows the build-out water requirement,reliability
reserve,siltation loss,and the resulting supplemental water requirement necessary to meet projected
City water demand.
TABLE 6
REQUIRED SAFE ANNUAL YIELD
FOR GENERAL PLAN BUILD-OUT
Acre-feet
(at 145 gal per Percent
Source of Demand Population per person) of Total__.._ _I
Existing (2000)Development 43,027 6,988 16.8%
New Development 12,973 2,107 23.2%
TOTAL 56,000 9,095 _100.0%
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TABLE 7
NEW WATER SUPPLY REQUIREMENTS
Component acre-feet
Required Safe Annual Yield 9,095
Safe Annual Yield as of 2000 7,540
Additional Safe Annual Yield Required
(based on per capita water demand ratios) 1,555
Reliability Reserve 2,000
Siltation (2000 to 2025) 250
Total Additional Water Supply Requirement 3,805
City policy adopted in 1987 as part of the Water Element states that the costs of developing
supplemental water sources will be borne by those making new connections to the water system.
Policy 6.1.3 continues this policy and is consistent with the Land Use Element(policy 1.13.4.)
7.0 MULTI-SOURCE WATER SUPPLY
7.1 POLICY
7.1.1 Multi-source Water Supply
The City shall continue to develop and use water resources projects to maintain multi-source water
supplies, and in this manner, reduce reliance on any one source of water supply and increase its
supply options in future droughts or other water supply emergencies.
BACKGROUND
Having several sources of water can avoid dependence on one source that would not be available
during a drought or other water supply reduction or emergency. There may greater reliability and
flexibility if sources are of different types(such as surface water and ground water)and if the sources
of one type are in different locations (such as reservoirs in different watersheds).
The Water Element of the General Plan,adopted in 1987,identified multiple water projects to meet
projected short and long term water demand. Again in November 1990, the Council endorsed the
multi-source concept.
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8.0 ALLOCATION OF NEW WATER SUPPLIES
8.1 POLICIES
8.1.1 Balancing Safe Yield and Overall Demand
When new water sources are obtained,the additional safe yield shall be allocated first to eliminate
any deficit between the adopted safe annual yield(Section 1.0)and the present demand as defined in
policies 3.1.4 at the time the new source is obtained..
8.1.2 Supplying New Development
A. The City will determine the water available for allocation based solely on the adopted per capita
water use rate(policy 3.1.2)times the current city population.This value is then subtracted from
the adopted safe annual yield value to determine the amount of allocation available each year.
Available allocations will be assigned to development in a way that supports balanced growth,
consistent with the General Plan. Allocations from a new water.supply project shall be
considered available at the time project construction is initiated.
B. Any safe annual yield from new water supply projects beyond that needed to balance safe annual
yield and present demand will be allocated. (A) one-half to the reliability reserve and
compensating for reduced yields due to siltation and(B)one-half to development,subject to the
requirements in Policy 8.1.3, "Reserve for Intensification and Infill."
C. Until a determination is made by the City Council that essentially all toilet and showerhead
fixtures in the City are replaced with low flow toilet and showerhead fixtures,projects may be
built if the developer makes changes, in facilities served by the City, which will reduce long-
term water usage equal to twice the water allocation required for the project.
8.1.3 Reserve for Intensification and Infill Development
The City will annually update the water available for allocation based on the difference between the
adopted safe annual yield(policy 1.1.2) and the present water demand (policy 3.1.4) as part of the
annual Water Resources Status Report.One-half of the water available for allocation(not to exceed
the total required for infill and intensification),as identified in the Water Resources Status Report,
will be reserved to serve intensification and infill development within existing city limits as of July
1994.
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8.1.4 Accounting for Reclaimed Water
Reclaimed water will be added to the City's safe annual yield consistent with policies contained
within this document for other water supply projects.
8.15 Private Water Supplies
When developments are supplied by private groundwater wells,the yield of those wells will not be
counted toward the City's safe annual yield. Such yield,however,will result in the demand for City
water supplies being lower than it otherwise would be,which may necessitate adjustments of the per
'capita water usage figure used to estimate overall demand.
BACKGROUND
The City has pursued numerous water supply projects over the years. (These projects are discussed
in Chapter 3 of the Urban Water Management Plan.) This part of the element addresses allocation of
these supplies once the yields from projects are realized. The City has identified these potential uses
for new supplies:
■ Eliminating any deficit between adopted planning figures and safe annual yield,
■ Compensating for reduced yields due to reservoir siltation;
■ Establishing a reliability reserve;
• Providing for water requirements for future development within the urban reserve area
designated in the General Plan;
■ Providing water for habitat management.
Allocation of new supplies can balance the needs of all areas identified while not compounding the
potential water shortage problems for existing City water customers.
The adoption of 145 gallons/per person/per day as a water supply planning figure would indicate
water is available for development,eliminating the need for retrofitting. Because 145 gallons/per
person/per day assumes that the retrofit component of the water conservation program is complete,
new development will continue to retrofit until the entire city is essentially retrofitted as determined
by the City Council.
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9.0 WATER ALLOCATION AND OFFSETS
9.1 POLICIES
9.1.1 Exemptions for Offsets
A. The City will not allow a project to reduce or eliminate the amount of the required allocation or
offset,to the extent that the project is supplied by a private well,with the following exceptions:
1. The City may reduce the amount of the required water allocation, to the extent that the
project is supplied by a private well serving non-potable water needs (such as irrigation)
which will not significantly affect the yield of City wells. Such a well may be operated by
the owner of the property containing the well only for the owners use. As an exemption,the
City may allow a well to supply landscape irrigation on more then one parcel if the irrigation
is:
a. for the common area of a condominium complex or other developments with similar
common areas as approved by the Utilities Director, and the well and irrigation
system are under the control of an owner's association;or
b. in a single commercial development,and the well and irrigation system are subject to
a recorded agreement among parcel owners, which is acceptable to the Utilities
Director and the City Attorney,.and which establishes responsibilities for operation
and maintenance of the common areas served by the well.
2. When an allocation or potential offset is not available,a well may be allowed to eliminate the
required offset for potable water needs only as an interim source until a new City water
source is available. Once a new source becomes available, the project will be required to
acquire an allocation from the City. Impact fees will be due at the time the development is
approved.
3. 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; and
4. 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 and will not impact the yields from City wells.
9.1.2 Basis for Allocations and Offsets
Required allocations and offsets will be based on long-term usage for each type of development.
(These use and offset factors will be determined and published by the City, and may be revised, as
warranted,by new information.)
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BACKGROUND
In 1988, the City began to formally account for long-term water usage in new development. The
allocations have been based on histories of water usage for various kinds of development. At first,
the City decided to allocate some water for new land development projects even though city-wide
water usage exceeded safe yield. As the 1986-1991 drought continued,and the projected completion
of proposed supplemental supply projects moved farther into the future,the City decided that there
should be no new development that would increase water usage. As a result,nearly all construction
since 1990 has been:
■ Replacement buildings, using the same or less water,
■ Additions or remodels which do not substantially affect water usage; and
■ Projects that have retrofitted facilities served by the City, to save (offset)twice the amount of
water that would be allocated to the project. Installation of low-flow toilets; showerheads,and
faucets have accounted for most of the offset credit. Substantial credits were also earned by
installing water-recycling equipment in businesses.
Also; a few relatively small projects were able to do little or no retrofitting because they were
supplied with groundwater through private wells. Some projects have utilized more than one of
these strategies to proceed despite the lack of water allocations.
10.0 RECLAIMED WATER
10.1 POLICIES
10.1.1 Reclaimed Water Quality
The City will produce high quality reclaimed water, suitable for a wide range of nonpotable uses.
10.1.2 Uses of Reclaimed Water
The City will make available reclaimed water to substitute for existing potable water uses as allowed
by law and to supply new nonpotable uses.
When deemed appropriate by the Utilities Director,new development shall be equipped with dual
plumbing to maximize the use of reclaimed water for non-potable uses.
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BACKGROUND
Reclaimed water is highly treated wastewater (sewage) which can be used for most nonpotable
purposes. The City's Water Reclamation Facility (formerly known as the Wastewater Treatment
Plant)has been upgraded to the point the effluent can be used directly for landscape and agricultural
irrigation and other uses such as industrial processes and toilet flushing in certain types of buildings.
Most treated effluent,in the past,has been discharged to San Luis Obispo Creek.A small amount of
effluent has been used at the treatment plant site for landscape irrigation. Reclaimed water will be
used for additional landscape irrigation at the Water Reclamation Facility and on City-owned land in
the vicinity, and for ponds to benefit wildlife.
Use of reclaimed water beyond the treatment plant area will require a distribution system separate
from other water lines.Reclaimed water can be used to supply nonpotable uses in new development
and to offset potable uses in existing development.These potential uses require a deliberate method
to account for reclaimed water use,consistent with policies concerning total water requirements and
other water sources.
Long-term funding for the necessary reclaimed water distribution system is expected to come from
charges for the use of reclaimed water.Initial expenses may be funded from bonds,low-interest State
loans, and developer contributions.
11.0 WATER SERVICE WITHIN THE CITY
11.1 POLICY
11.1.1 Water Service within the City
A. The City will be the only purveyor of water within the City.
B. Appropriate use of privately owned wells may be allowed with the approval of the Utilities
Director, consistent with policies 8.1.5 and 9.1.1.
BACKGROUND
Historically,the City has been the sole water purveyor within the City limits.This allowed the City
to maintain uniformity of water service and distribution standards,and to be consistent in developing
and implementing water policy.In continuing to be the sole water purveyor,the City will maintain
control over water quality,distribution and customer service,as well as ensure consistency with the
City's General Plan policies and goals.
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