HomeMy WebLinkAbout07/20/2000, 1 - 2000 WATER RESOURCES STATUS REPORT t
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: Jul 20 2000
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CITY OF SAN LUIS O B I S P O
FROM: John Moss, Utilities Directo;�/I%—
Prepared By: Gary W. He4/erson, Water Division Manager!Va
SUBJECT: 2000 Water Resources Status Report
CAO RECOMNMNDATION
Receive and file report.
DISCUSSION
The purpose of the annual "Water Resources Status Report" is to provide an overview of various
aspects of the City's water supplies. The attached report discusses four major topics: 1.) Existing
Water Supply Status, 2.) Multi-Source Water Supply Projects, 3.) Water Conservation Program,
and 4.)Projected Water Supply Situation.
REPORT SUMMARY
Existing Water Supply Status
The rainfall for 1999/2000 was about average for this area. The City's combined total water
storage,above minimum pool,in Salinas and Whale Rock Reservoirs is 42,445 acre feet(as of June
1,2000)which is 98.4%of the maximum City available storage. Groundwaterproduction for 1999
was 159 acre feet
The City's per capita water demand has increased from the low drought period (1991) use of 86
gallons per capita per day (gpcd) to 129 gpcd for 1999. This past year's use was below the 1997
use rate of 132 gpcd.
Water Available for Development
The policies in the Water Management Element to the General Plan determine the water available
for new development. The policies use a planning figure of 145 gpcd times the current population
to determine the present demand. This figure is then subtracted from the city's adopted safe annual
yield to determine water available for development as shown in the table below.
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Council Agenda Report—2000 Water Resources Status Report
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Table 1: Water Available for Development
Year Population Present Water Safe Annual Water Available
Demand Yield' for Allocation
@ 145 gpcd
2000 43,027 6,988 a.f. 7,540 a.f. 552 a.f.
1 From Water Management Element,Table l: includes reductions due to siltation to date
Per Water management Element Policy 8.1.3,one-half of the water available for allocation will be
reserved to serve intensification and infill development within existing city limits as of July 1994.
Therefore,276 acre feet is available to serve new annexation areas outside the July 1994 city limits.
Malo-Source Water Supply Projects
One of the major goals of the Council is the pursuit of additional long term water supplies to meet
the current and future water demands of the community. The City is therefore pursuing the Water
Reuse Project,Nacimiento Pipeline Project, and the Salinas Reservoir Expansion Project to meet
these needs. The Water Reuse Project has the potential to be accomplished in the shortest time
frame,with a projected water delivery as early as spring of 2003.
The draft EIR for the Nacimiento Pipeline Project is currently being revised to address comments
received on the initial draft EIR. The current schedule for the project anticipates certification of the
EIR by early 2002 and water deliveries around the year 2006.
The EIR for the Salinas Reservoir Expansion Project was certified on June 2, 1998. Hearings
associated with the City's water rights permit were held in October of 1999 and a decision by the
State Water Resources Control Board is expected this summer or fall. Additional studies and
analysis are underway associated with the structural adequacy of the existing dam and expanded
facilities. An optimistic schedule for the completion of the construction work for the Salinas
Reservoir Expansion Project would be around the year 2005.
Water Conservation
The Utilities Conservation Office continues to implement the Best Management Practices(BMP's)
established by the California Urban Water Conservation Council. The key component of the City's
continuing efficient use of water is water savings available through the retrofit of existing toilets
and showerheads with low flow fixtures. The retrofit of the community is being accomplished
using three different programs: 1.) Retrofit Upon Sale; 2.) Retrofit Rebate; and 3.) Retrofit Offset
(for new development). To date, 24,407 bathrooms (toilets) have been retrofitted either through
the Retrofit Rebate, Retrofit Upon Sale and/or the Water Offset Programs. This represents an
annual estimated water savings of approximately 850 acre feet.
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Council Agenda Report—2000 Water Resources Status Report
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Projected Water Supply Situation
The City utilizes a computer program to project how long the City's available water supplies would
last based on a number of assumptions. The model uses historical drought weather patterns,
projected water demands,etc.,to forecast the City's water supply position and to make certain water
policy recommendations. With the favorable water supply situation, the model predicts current
water supplies would last until May of 2007 (if the City was to enter into a drought period with
conditions comparable to those experienced in the 1986-91 drought).
FISCAL IMPACT
There is no fiscal impact associated with the recommended action.
Attachment: 2000 Water Resources Status Report
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ATTACH, �%49 _
City of San Luis Obispo
111 Water Resources Status Report
June 2000
Prepared by: Gary Henderson, Water Division Manager
Ron Munds, Utilities Conservation Coordinator
Sue Baasch, Administrative Analyst
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Contents
I. Existing Water Supply Status 1
Water Consumption 2
Water Available for Development 3
II. Multi-Source Water Supply Projects 3
Water Reuse 4
Nacimiento Water Supply Project 5
Salinas Reservoir Expansion Project 5
Groundwater 6
III. Water Conservation Program 6
Bathroom Retrofit Summary 7
Water Audit Program 7
Public Information& Education 7
Potential New Water Conservation Programs 8
IV. Projected Water Supply Situation 8
Reservoir Storage Curve 9
V. Summary 9
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�II tia"io.i:7:L:J1
City of San Luis Obispo
2000 Water Resources Status Report
The annual Water Resources Status Report is prepared to provide a current overview of various
aspects of the City's water supplies. The report addresses four major topics: 1.) Existing Water
Supply Status, 2.)Multi-Source Water Supply Projects, 3.) Water Conservation Program, and 4.)
Projected Water Supply Situation. The report provides an opportunity to evaluate the current
water supply position of the City and identify potential issues relative to existing polices and
projected development.
I. EXISTING WATER SUPPLY STATUS
The winter season began with Salinas and Whale Rock Reservoirs at approximately 60% and
90% of total storage capacity respectively. This year's rainfall has been about average with
Whale Rock Reservoir receiving 23.57 inches and Salinas Reservoir recording 21.24 inches.
Normally Salinas Reservoir receives more rainfall than Whale Rock, but this years rainfall
patterns resulted in approximately the same amount at each reservoir.
Salinas and Whale Rock Reservoirs are operated in a coordinated manner with the majority of
the water needed to meet city water demand provided from Salinas Reservoir. This coordinated
operation results in an increase in the safe annual yield of these two sources since Salinas
Reservoir has a much larger watershed and fills and spills more often.
Only a small amount of water was supplied from Whale Rock this year which allowed this year's
rainfall to fill and spill the dam beginning February 15, 2000. Salinas Reservoir also filled this
year and began spilling on March 12, 2000. The City received 1,161 acre feet from Whale Rock
and 5,416 acre feet from Salinas Reservoir in 1999. As of June 1, 2000, the City's available
water storage in Salinas Reservoir(above minimum pool)was 21,163 acre feet. The City's share
of the Whale Rock storage (above minimum pool) was 21,282 acre feet. The combined water
storage available to meet city water needs is 42,445 acre feet.
In addition to surface water supplies from the two lakes, the City utilizes a limited amount of
groundwater to meet city water demands. Groundwater production reached a high of
approximately 2,000 acre feet during the early 1990's but has experienced a significant reduction
as a result of groundwater contamination in the area Two wells were shut down in 1992/93 due
to elevated nitrate levels as well as PCE contamination. The Water Management Element
(W.M.E.) identifies 500 acre feet per year of groundwater production, which is added to the safe
annual yield from the lakes, as the basis for water allocation to new development and planning
additional water supply needs. This past year's well production (January through December)
was only 159 acre feet. The low groundwater production this year is partly attributed to a pump
failure at one of the well sites. The City has initiated a study relative to potential increases in
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1999 Water Resources Status Report
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groundwater production. Staff are evaluating treatment requirements as part of this study and
anticipate presenting the results of the study to Council this summer.
Based on the available water storage in both reservoirs, estimated groundwater production and
assuming the return of drought conditions as experienced during the late 1980's, the City has
approximately 7 years of water supply, according to the computer storage model as shown in
Figure 4 (figures are at end of report). The model assumes that conservation measures are
implemented when supplies are estimated to last only three years. The various stages of
conservation are indicated on Figure 4 and are discussed in more. detail in the Water Shortage
Contingency Plan.
Water Consumption
Based on policies contained in the Water Management Element, the City has adopted a figure of
145 gallons per capita per day (gpcd) as the planning figure for projecting future water supply
needs and determining the availability of water for new development. It should be noted that the
145 figure is not the amount that an average resident in the city would use. The basis of the
number is the total water pumped into the water system divided by the city population. This
figure includes water used by hotels, restaurants, parks, etc. With the adoption of the 145 gpcd
figure, staff monitors city-wide water use to insure that actual water use does not exceed this
planning figure.
Prior to the drought of 1986-91, per capita water use reached a high of 182 gpcd (see Figure 3).
With the implementation of mandatory conservation measures during the drought, water use
reached a low of 86 gpcd in
1991. The impacts to the
community relative to this Table 1: Population Estimates & Water Use
very low water use were year Population Acre Feet Per Capita
visually evident with the 1990 41,958 4,183 89 gpcd
loss of landscaping 1991 42,178 4,063 86 gpcd
throughout town. Since the
end of mandatory rationing 1992 42,922 4,712 98 gpcd
(i.e. penalties) following the 1993 43,397 5,008 103 gpcd
end of the drought, water 1994 43,919 5,200 106 gpcd
use has increased each year 1995 41,295 5,574 120 gpcd
until 1997. Water use for 1996 41,404 5,791 125 gpcd
1998 saw a reduction from 1997 41,807 6,220 133 gpcd
the 1997 figure of 132 gpcd 1998 42,201 5,853 124 gpcd
to a water use of 123 gpcd. 1999 42,446 6,172 129 gpcd
The reduction is likely due
to the fact that in 1997 the
rainfall for the year ended in mid-January while in 1998 the rainfall continued into May. With
this past years' more normal rainfall pattern, water use increased to 129 gpcd. This demonstrates
that outside irrigation throughout the community has a notable impact on the overall water use
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1999 Water Resources Status Report
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for the city and should be one of the key focuses of the ongoing water conservation efforts. As
identified in the Water Management Element, the City uses 145 gpcd as the planning figure for
projecting long-term water supply needs. Staff monitor water use on a monthly basis to insure
that annual per capita use does not exceed the 145 figure.
Water Available for Development
The policies in the Water Management Element to the General Plan determine the water available
for new development. Section 8.2.A. states "The City will make available to new development
only that amount of safe annual yield which exceeds present water use(policy 3.4)." Policy 3.4 and
related policies define present water use as the current population times the adopted per capita
water use rate (145 gallons per capita per day). Since the 145 gpcd figure was based on the
assumption that the entire City had been retrofitted with low flow toilets and fixtures,the polices
continue to require retrofitting of existing facilities served by the City to obtain a water allocation
for new development. Based on these policies, the table below indicates the water available to
allocate to new development in 2000. Figure 5 (attachment to this report) illustrates the City's
available water supplies and future supply project timing versus the projected water demands in the
future. The future water demand projections are based on a 1%population growth rate and the 145
gpcd planning figure.
Table 2: Water Available for Development
Year Population Present Water Safe Annual Water Available
Demand Yield' for Allocation
@ 145 gpcd
2000 43,027 6,988 a.f. 7,540 a.f. 552 a.f.
1 From Water Management Element,Table l: includes reductions due to siltation to daze
Per Water management Element Policy 8.1.3,one-half of the water available for allocation will be
reserved to serve intensification and infill development within existing city limits as of July 1994.
Therefore, 276 acre feet is available to serve new annexation areas outside the July 1994 city
limits.
II. MULTI-SOURCE WATER SUPPLY PROJECTS
In November, 1990, the City Council adopted a multi-source water supply policy. The adopted
W.M.E. Policy 7.1 reaffirmed the City's strategy of utilizing multiple water supply sources to meet
our current and future water needs. The policy states that "The City shall continue to develop and
use water resource 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."
Policies which were adopted in the Water Management Element, the Urban Water Management
Plan, and the Land Use Element have revised previous water demand projections. The projected
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1999 Water Resources Status Report F
Page 4
total amount of water to serve General Plan build-out, under the revised plans and policies, is
11,346 acre feet. This figure includes a 2,000 acre-foot reliability reserve and 250 acre feet for loss
of safe annual yield due to siltation (from 2000 to 2025) at the reservoirs. The City's current
adopted safe annual yield (for the year 2000) from the reservoirs and groundwater is 7,540 acre
feet. This safe annual yield figure includes estimated siltation losses at the reservoirs to date. This
results in an additional supplemental water supply requirement of 3,806 acre feet per year.
To provide the required water resources to achieve our General Plan build-out goals, the City is
pursuing the Water Reuse Project, Nacimiento Pipeline Project, and the Salinas Reservoir
Expansion Project to provide additional water resources for the community. The following is a
brief status report on each of these projects being considered to meet the City's future water needs.
Rater Reuse
Recycled water will provide a reliable long-term source of water for the City. In 1994, the City
completed a $30 million upgrade of the Water Reclamation Facility (WRF) to comply with
requirements for discharge to San Luis Obispo Creek. The tertiary treatment, required for
discharge,produces recycled water that can be used to irrigate parks,playgrounds,and landscaping.
The recycled water may also be used in industrial processes,for construction,and many other non-
potable uses.
The City Council certified the final Environmental Impact Report for the Water Reuse Project on
March 25, 1997. The US Fish and Wildlife Service and the National Marine Fisheries Service have
issued biological opinions concerning the tidewater goby and the steelhead. On May 8, 2000,the
State Water Resources Control Board (SWRCB) issued an Order approving the City's petition to
reuse the reclaimed water.
Staff estimates that using recycled water for landscape irrigation and other approved uses will offset
approximately 400 acre-feet of potable water that has been used for irrigation. Additional recycled
water will replace potable water that would be required for irrigation and other non-potable uses in
future developments.
In December 1997,Brown and Caldwell(B&C)was selected as the design consultant for the Water
Reuse Project. They have completed an engineering report describing the treatment processes,the
water quality and the areas where the water will be used so that the Regional Water Quality Control
Board and the State Department of Health Services can review the project and approve a Master
Reclamation Permit.
B&C has completed a draft Preliminary Design Report defining and estimating the costs of
alternatives for pipeline routes and treatment plant modifications. After staff has reviewed the
report and Council has approved the selection of the preferred alternatives,B&C will complete the
final construction drawings and specifications. Staff estimates that recycled water may be delivered
to the first customers by the spring of 2003.
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'1999 Water Resources Status Report
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Nacinuento Water Supply Project
The County of San Luis Obispo is continuing to pursue the Nacimiento Water Supply Project to
make beneficial use of its entitlement of 17,500 acre-feet per year (afy) of water from Lake
Nacimiento. The current phase of the project involves the preparation of an Environmental Impact
Report(EIR)and preliminary engineering analysis. The City of San Luis Obispo is participating in
the project with a requested allocation of 3,380 afy (as approved by Council on September 20,
1994).
The draft environmental impact report for the Nacimiento Project was released for public comment
in August of 1997. The comment period was scheduled to close on October 15, 1997, but due to
requests by north county agencies and individuals,the comment period was extended to February 1,
1998. Based on the comments received, a revised draft EIR was deemed necessary to assess
alternative pipeline alignments and project alternatives. An alternative pipeline alignment has been
identified which will address a number of the concerns raised by individuals and agencies. The
new alignment will follow Nacimiento River (along the banks) through Camp Roberts property.
The pipeline would cross Highway 101 and Salinas River to River Road. The route would remain
on the east side of the Salinas River until it passes Atascadero. The pipeline would then cross to the
west side of Salinas River and return to the original alignment. This new alignment will be studied
in the revised draft EIR for the project and will eliminate the construction impacts relative to
Nacimiento Lake Road and Vine Street (Paso Robles), however the new alignment may result in
increased impacts to the environment as much of it is not in established rights-of-way.
The current schedule anticipates that the revised draft EIR will be released in fall of 2001 for public
review. The schedule anticipates that the certification of the final environmental impact report for
the Nacimiento Project will be considered by the Board of Supervisors by early 2002. Following
certification and project approval, the County will initiate procurement of final participation
agreements with the project participants. The County will then proceed with final design,
engineering and construction. If the project proceeds on the current schedule,water deliveries from
Nacimiento could occur around the year 2006.
Salinas Reservoir Expansion Project
The Salinas Reservoir Expansion Project envisions the installation of operable spillway gates which
would raise the maximum water level by 19 feet. This would increase the storage capacity in the
reservoir from 21,843 acre feet to 41,792 acre feet. Based on this increase in storage capacity,the
safe annual yield from Salinas Reservoir is estimated to increase by 1,650 acre feet per year.
The Final Environmental Impact Report for the project was certified on June 2, 1998. Following
certification of the EIR, staff requested a hearing before the State Water Resources Control Board
to resolve the protest to the request for a time extension relative to the City's water rights permit.
The hearing was finally scheduled for October 12'and 13t'of 1999. Due to the length of testimony
and the number of expert witnesses,the hearing required a third day to complete and ended late in
the day on October 18, 1999. Following the hearing process, written closing arguments were
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1999 Water Resources Status Report 5
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prepared by all parties (i.e. City of San Luis Obispo, City of Paso Robles, and California
Sportsfishing Protection Alliance) and submitted to the Board in December. Each party then
reviewed the other parties written arguments and prepared rebuttals which were submitted to the
Board in January of 2000. The Board staff is currently preparing an analysis and recommendations
to the Board for their consideration. The draft decision is expected to be released for review in the
next several months and the Board's decision is expected shortly thereafter.
On a second front,URS Greiner(formerly Woodward-Clyde)has been preparing an analysis of the
structural adequacy of the existing dam and proposed expanded facility. The work has involved
discussions with the State Division of Safety of Dams to insure compliance with the latest
standards. The draft document is currently being finalized and will be brought to Council on July
18, 2000. Other work associated with development of detailed mitigation plans have been placed
on hold pending the outcome of the State Board hearings discussed above.
Groundwater
The current groundwater program utilizes three wells for domestic use, two wells for irrigation at
the City golf course and one well at the Corporation Yard for construction water uses. The City's
two largest producing wells,the Auto Parkway and Denny's wells,were shut down in 1992/93 due
to elevated nitrate levels. The Pacific Beach#1 & #2 wells are not operated simultaneously due to
the close proximity of the wells and the interference problems which occurs between the two sites.
At this time, the three active domestic wells are producing an average of 18 acre feet per month
which represents about 3%of the total City water demand. The relatively small groundwater basin
which supplies the majority of the City's groundwater production is recharged very quickly
following normal rainfall years. The water levels in the basin also fall relatively quickly following
the end of the rain season. The W.M.E.has adopted a goal of 500 acre feet per year of groundwater
production. This past year's production from the available wells was only 159 acre feet which was
a decrease from the previous year's amount of 289 acre feet.
The City has contracted with Team Engineering and Management,Inc.to provide an analysis of the
potential for increasing groundwaterproduction. The analysis will review options for conjunctively
using groundwater and surface water sources (Salinas and Whale Rock). In addition to the work
being performed by consultants,City staff are analyzing options for treatment of the contaminated
groundwater. The results of these studies are anticipated to be completed this summer and
presented to Council for consideration and direction.
III. WATER CONSERVATIONPROGRAM
Water conservation has played an ever increasing role in the City's over-all water supply
development and management strategies since 1985. With the adoption of the Urban Water
Management Plan (UWMP) in November 1994, the policies regarding water conservation will
provide the essential foundation in sustaining long-term water supply dependability by using our
existing supplies more efficiently.
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In September 1991, the Council approved and authorized the Mayor to sign the "Memorandum
of Understanding" (MOU) with the California Urban Water Conservation Council regarding
urban water conservation and the implementation of the sixteen (now consolidated to fourteen)
"Best Management Practices" (BMPs). The BMPs were presented as part of the UWMP. The
MOU acts as a road map for the City's long-term water conservation program and signifies a
commitment to the BMP process.
The following information is a summary of the water conservation program's key components:
Bathroom Retrofit Summary
With the adoption of the UWMP in 1994, bathroom retrofitting has been identified as a
significant water demand management strategy and integral part of the City's overall
management plan. To date, 24,407 bathrooms (toilets) have been retrofitted.either through the
Retrofit Rebate, Retrofit Upon Sale and/or the Water Offset Programs. This represents an annual
estimated water savings of approximately 850 acre feet. Table 3 summarizes the toilet retrofit
activity during 1999.
Table 3: Summary of Toilet Retrofit Activity
Year Retrofit Rebate Water Offset Retrofit Upon Sale
1999 171 21068 19909
Water Audit Program
The Utilities Conservation Office offers free indoor and outdoor water audits upon request. The
requests are typically received from people experiencing high water bills, residents participating
in the low income assistance program or customers requesting a utility bill adjustment through
the Utility Billing Adjustment Committee. The Water Audit Program has been very active this
last fiscal year due mainly to the follow-ups to high meter read investigations, an activity the
office assumed during the last fiscal year. Additionally, the numbers for water audits may be
slightly low because the tracking mechanisms for audits has not been utilized fully to date. For
the last several years, the office has averaged about 250 audits per year. As of May 24`h of this
year, the office has performed approximately 430 audits for 1999/00 fiscal year. A majority of
these have been a direct result of high read investigations which required follow-up surveys.
These water audits often reveal problems which are then corrected by the property owner, which
results in lower water use and associated billing charges.
Public Information A Education
In its ongoing effort to educate the public on efficient resource utilization, the Utilities
Conservation Office provides informational brochures on a variety of water conservation and
recycling topics upon request. Additionally, staff has produced a quarterly newsletter which
focuses on current information regarding water, wastewater and solid waste issues. Additional
information has been distributed through paid media advertising and public service
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1999 Water Resources Status Report '
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announcements. The current emphasis in the water conservation program's information and
education campaign is efficient irrigation practices. Six irrigation workshops have been
presented during the past fiscal year and have been well received by the community.
In addition to the above programs,the Utilities Department has been working with the San Luis
Obispo Coastal School District to implement a water education program which was approved by
the District in 1999. The start-up of the water education program began in November of 1999. The
program targets third and fourth grades,to compliment the study of water within the school district.
Teachers were largely enthusiastic about the new program,particularly the field trip to the Water
Reclamation Facility. Evaluation forms were given to many teachers and feedback has been very
positive.
During the school year 16 Class Presentations and 13 Field Trips were given throughout the
schools within the city. The class presentations were 45 minutes and covered the subjects of: Water
Cycle, Water Treatment,Water Use, Water Conservation,and Water Reclamation. The classroom
presentation is a prerequisite for the field trip.
The department's hope is that programs are lively, fun and interesting, so that the teachers will
continue to want to use the presentations, water education toolkits and tours as a way of
enhancing their current water education curriculum. The benefits are immediate and long-term.
Instilling water awareness in children leads to increased parental water awareness. It also
positively affects future generations: these students are tomorrow's adults and they will have the
information to make informed and appropriate decisions about water. With the initial year
completed, it is expected that demand for the programs and field trips in the upcoming year will
be even greater than 1999-2000.
Potential New Water Conservation Programs
Because of the City's affiliation with the California Urban Water Conservation Council
(CUWCC), valuable information regarding water conservation program development and
implementation is available. Most of the nation looks to California, and more specifically to the
CUWCC and the BMP's when developing water efficiency programs. Given this fact,the City's
water conservation program uses the CUWCC information to determine if the implementation of
a new program will provide dependable water savings in a cost effective manner.
One such program now being evaluated for implementation is the recently added BMP number
six concerning a rebate program for high-efficiency washing machines. There is a study
currently under way to quantify the reliable water savings attributable to the use of high-
efficiency washing machines. Once the study is complete, staff will evaluate the conclusions of
the report and use the information to determine if the implementation of a rebate program in the
City will yield favorable results. If determined to be feasible, staff would return to Council with
the results of the study and recommend the appropriation of funds to support the program.
Additionally, staff is researching the feasibility of implementing additional irrigation efficiency
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'1999 Water Resources Status Report
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programs such as complementary irrigation workshops to the existing workshop program and
irrigation hardware rebates for upgrades to more efficient equipment.
IV. PROJECTED WATER SUPPLY SITUATION
Reservoir Storage Curve
The Reservoir Storage Curve is integral to the City's annual water plan analysis. It is a computer
model used to estimate the City's future reservoir storage based on historical drought weather
patterns,water use projections, reservoir data and available groundwater supplies. The model is
used to forecast the City's water supply position and to make certain water policy
recommendations. The model also assumes implementation of Stage I conservation when supplies
are projected to last only three years. .Stage H and III conservationmeasures are implemented when
water supplies are estimated to last only 2 years and 1 year, respectively(as shown on Figure 4).
The curve has been updated to reflect the City's current storage and the policies contained in the
Urban Water Management Plan.
The model predicts current water supplies would last until May of 2007 (Figure 4), under a set of
assumptions that represent the average weather conditions during the worst four years of the
drought period from 1986-91.
V. SUMMARY
With both reservoirs nearly full,the City is currently in a favorable water supply situation. Even
with this favorable short-term outlook,the City still needs to develop additional supplemental water
supplies to meet the goals of the General Plan. Based on the cost projections for developing new
water supplies, it is evident that water conservation will continue to be a crucial element of the
City's water resources planning in the future. With the multi-source water policy, a number of
supply projects under development, strong water conservation program and other related policies
which were adopted as part of the W.M.E., the City is pursuing a direction which will create a
reliable supply of water to meet our customers current and future needs.
Attachments: 1. Definitions
2.Figures 1-5
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FF t }
Definitions
Safe Annual Yield:
The maximum quantity of water which can be delivered from the water
source each year during a critical dry period(i.e.historical drought period).
Acre Foot:
* 1 acre foot = 325,851 gallons
* Enough water to cover a football field with 1 foot of water
* Enough water to serve approximately 3.5 average single family homes (in San Luis
Obispo)per year
Gallons per Capita per Day(gped):
Calculation= Total Acre Feet x 325,851
City Population 365
Present Water Demand:
Calculation= 145 gpcd x Current City Population x 365
325,851
Salinas Reservoir:
Maximum Storage Capacity=23,842.9 acre feet
Minimum Pool=storage amount when water extractions must cease=2,000 acre feet
Surface Area=730 acres
Drainage Area= 112 square miles=.71,700 acres
Whale Rock Reservoir:
Maximum Storage Capacity=40662 acre feet
Minimum Pool=storage amount when water extractions must cease=2,000 acre feet
Surface Area=594 acres
Drainage Area=20.3 square miles= 13,000 acres
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