HomeMy WebLinkAbout07-17-2012 c1 water resources status reportcounci lagenOa I epoit
Meeting Date
July 17, 201 2
Item Number C l
C I T Y O F S A N L U I S O B I S P O
FROM :
Carrie Mattingly, Utilities Directo r
Prepared By :Wade Horton, Water Division Manager
SUBJECT :2012 WATER RESOURCES STATUS REPOR T
RECOMMENDATION
Receive and file the 2012 Water Resources Status Report .
DISCUSSIO N
An annual report relative to the City's water resources has been provided to the City Council since
1985 . The 2012 Water Resources Status Report (WRSR) provides an overview and update of th e
City's water resources, water supply status, and its ongoing water conservation program effort s
(Attachment) and is summarized in this Council Agenda Report .
Existing Water Supply Statu s
Considering City dependence on local surface water sources, rainfall plays a significant factor i n
community water supply management . Last year's rainfall (in combination with the prior year's
carryover storage) positions the City with a more than adequate water supply in 2012 . In the event San
Luis Obispo County entered into an extended drought period, based on data used in the City's wate r
supply model, water supplies are projected to last into 2024 .
While the current water supply situation is favorable, the City will continue to incrementally expand
the use of recycled water and continue its water conservation efforts to comply with State regulation s
and ensure long-term efficient use of water resources .
Multi-Source Water Supply Statu s
For over 20 years, a major Council goal was the pursuit of additional long-term water supplies to mee t
the current and future community water demand .With the recycled water program, ongoing wate r
conservation efforts, and the Nacimiento Pipeline Project the City has attained this goal .,a significan t
accomplishment ensuring reliable water supplies for the community well into the future .
The City's two water supply reservoirs (Salinas and Whale Rock) were at 78 percent and 68 percen t
of total storage capacity respectively as of June 01, 2012 . The Nacimiento Pipeline Project bega n
water deliveries to the City in January of 2011 . The City has contractual rights for 3,380 acre feet per
year from Nacimiento Reservoir .
Additional users continue to be added to the City's recycled water system . Recycled water use fo r
calendar year 2011 year totaled approximately 158 acre feet, up three percent from 153 acre feet i n
the previous year . Additionally, three new sites (six additional meters) were connected to the City's
recycled water distribution system during 2011 to provide landscape irrigation .
2012 Water Resources Status Report
Page 2
Water Consumptio n
The City's total water use in calendar year 2011 was 5,285 acre-feet (AF) compared to 5,489 AF i n
calendar year 2010 . The City's per capita water use continues its downward trend (see Table 1).
The per capita use rate is not the amount that the average person uses but takes into account all
water uses including residential, commercial, industrial, and landscape . In 2011 the water use rat e
decreased from 109 to 104 gallons per capita per day (gpcd) compared to 2010 . Decrease in pe r
capita demand is consistent with nationwide trending, due in part to conservation success an d
recessionary impacts (vacancy rates, etc .).
Table 1 : Population Estimates, Water Use & Rainfal l
Year Population Total Water Us e
(acre feet)
Per Capit a
(gpcd)
Rainfall '
(inches )
2002 44,482 6,032 121 13.0 8
2003 44,357 5,968 120 16A 0
2004 44,298 6,239 126 17 .7 3
2005 44,687 6,098 122 16 .2 1
2006 44,559 5,999 120 14 .8 0
2007 44,433 6,493 130 6 .1 4
2008 44,579 6,359 127 15 .8 4
2009 44,829 6,134 122 18 .1 8
2010 44,948 5,489 109 33 .5 3
2011 45,418 5,285 104 21 .1 6
Ten-year per capita average 120 .1
1 . Rainfall amounts for calendar year source : Cal Poly CIMIS Weather Station
Based on the policies adopted in the City's Water and Wastewater Management Element (WWME),
Table 2 summarizes the available water supplies to serve the community's water demands .
Table 2 :Water Resource Availabilit y
Ratcr Resourc e
Salinas & Whale Rock Reservoirs
2011
-Annual A~ailabili h
6,940 AF Safe Annual Yield
Nacimiento Reservoir 3,380 AF Contractual Limi t
Recycled Water 160 AF 2011 Annual Usag e
Siltation* to 2060 (500 AF)WWME Policy A 4 .2 .2
TOTAL 9,980 AF
*Siltation occurs when small dirt particles get into reservoirs and fill them up . Siltation reduces capacity in the reservoir thereby reducin g
the amount of water than can be stored in the reservoir . Siltation is subtracted from the available water total .
Water Supply Accounting and Deman d
WWME policy specifies that the City will account for water supplies necessary to meet thre e
specific community needs : 1) Primary Water Supply, 2) Reliability Reserve, and 3) Secondar y
Water Supply, which are discussed in detail in the 2012 Water Resources Status Report
(Attachment) and summarized in Table 3 .
2012WaterResources Status Report Page 3
Table 3 : 2011 Water Supply Accountin g
Water Demand Managemen t
The City's water conservation program continues to implement the California Urban Wate r
Conservation Council's Best Management Practices as defined in the Memorandum of
Understanding Regarding Urban Water Conservation in California (of which the City is a
signatory). The water conservation program will continue to play an important role in the future a s
the City faces new water supply challenges attributable to climate change and regulator y
requirements related to statewide water use reduction goals .
Projected Water Supply Situatio n
The City utilizes a computer model to project how long the City's available water supplies will las t
based on a number of assumptions . The model uses historical drought weather patterns, projected wate r
demands, and other factors to forecast the City's water supply position and to make water polic y
recommendations . Assuming ongoing drought conditions, the model estimates current water supplie s
will last into the year 2024 .
Summary
For the past 20 years, the City of San Luis Obispo has been pursuing additional water resources to mee t
the City's current and future water demands . The City has demonstrated leadership in the
implementation of water conservation strategies since the late 1980's and the community has embrace d
the importance of using its water resources wisely. With the Council's support for the use of recycled
water and the completion of the Nacimiento Project, the City is well positioned to meet current an d
future community water needs . The Council has accomplished the "multi-source" water supply policy
as identified in the Water and Wastewater Management Element of the General Plan and has als o
successfully established a Reliability Reserve which will serve the City well in the event of a wate r
supply contingency .
FISCAL IMPAC T
No fiscal impact is associated with the recommended action .
ATTACHMEN T
2012 Water Resources Status Repor t
..,wuaul y cuu 4,;;L C I u :o luweµto ut a ly hol:on , i ::u :er r uurues slows :erl .aoo:.
Total Primary Al atcr Rcliabilit~ RescrN c Secondary \\Me t
Supple Supply
9,980AF
7,695 AF
1,222 AF
1,063 AF
Attachment 1
Prepared by :
Ron Munds, Utilities Conservation Manage r
Jennifer Metz, Utilities Project Manage r
Wade Horton, Water Division Manage r
!Utilities city o f
Della s~r tuffs oBispo
Attachment 1
TABLE OF CONTENTS
I.EXISTING WATER SUPPLY STATUS 1
Current Supply Status 1
2011 Summary 1
II MULTI-SOURCE WATER SUPPLY :2
Water Supply Sources 3
Salinas & Whale Rock Reservoirs 3
Nacimiento Reservoir 3
Recycled Water 3
Groundwater 3
Water Resource Availability 4
Water Supply Accounting 4
IIL WATER DEMAND MANAGEMENT 5
IV.PROJECTED WATER SUPPLY SITUATION 7
Reservoir Storage Curve 7
V..SUMMARY 7
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Attachment 1
City of San Luis Obisp o
2012 WaterResourcesStatus Repor t
The 2012 Water Resources Status Report updates the City Council and community members on water suppl y
accounting and demand projections as specified in the Water and Wastewater Management Element of th e
General Plan,Policy A 5 .3 .1 .
I.Existing Water Supply Statu s
II.Multi-Source Water Suppl y
III.Water Demand Managemen t
IV.Projected Water Suppl y
I . EXISTING WATER SUPPLY STATU S
The City currently utilizes five water sources to meet community water demand :
1.Salinas Reservoir (also referred to as Santa Margarita Lake )
2.Whale Rock Reservoi r
3.Nacimiento Reservoi r
4.Recycled water from the City's Water Reclamation Facilit y
5.Groundwate r
Current Supply Statu s
As of June 1, 2012, the City's available water storage in Salinas Reservoir was 18,573 acre feet . The City's
share of the Whale Rock storage was 15,287 acre feet . The combined total water storage available to mee t
City water needs from these two sources was 33,860 acre feet, equating to 73 percent of maximum availabl e
storage .
Based on available storage from Salinas & Whale Rock reservoirs, contractual water from Nacimiento
Reservoir, estimated groundwater production, estimated recycled water deliveries, and assuming an extende d
drought until reservoirs levels are drawn down to minimum pool (see Definitions)the City has approximatel y
eleven years of water supply .
This estimate is based on data derived from the City's Reservoir Storage Model and is shown in Figure 5
(figures are provided at the end of report). The model assumes conservation measures, consistent with th e
City's Water Shortage Contingency Plan,are implemented when supplies are estimated to last three years o r
less . The various stages of conservation are indicated in Figure 5 . The Water Shortage Contingency Pla n
details the City's conservation measures related to drought and is an appendix to the Urban Water
Management Plan ,adopted June 2011 .
11111111111M .'-*UMW
The City now has five water sources, achieving th e
goal of a diversified water supply portfolio to mee t
current and future community need s
The report covers four main areas :
Department
Cty of San Luis Obispo
201 .2 Water Resources Status Report Attachment 1
Page 2
2011 Summar y
Table 1 summarizes City 2011 water demand per source . The total 2011 calendar year water demand (base d
on water production figures) was 5,285 acre feet . Water use per category is shown in Chart 1 .
Table 1 : 2011 City Water Demand Sources (acre feet )
Salinas Whale Rock*Nacimient o
2,830 14 2,181
Groundwater Recycled Total Water Used I
160 5,28 5100
*Water delivered to Cal Poly State University is excluded from City Water Deman d
Historical water use is summarized in Table 2, as well a s
corresponding population, per capita use rate, an d
precipitation . The 2011 per capita water use wa s
approximately 104 gallons per person per day (gpcd),
representing a 5 gpcd decrease from the previous year .
The decrease in per capita demand is consistent wit h
nationwide trending, due in part to the success o f
conservation and recessionary impacts .
The ten-year per capita average water use is 120 .1 gpcd .commerc r ...Multl-
Institutional FamilyBased on policies contained in the Water and Wastewater 34%Residentia lManagementElement of the General Plan (WWME), the 19 %
City uses the ten-year average to project water required to Chart 1 : 2011 Water Use by Categor y
serve build-out population as identified in the Land Use
Element of the General Plan .Water use per customer class is summarized in Chart 1 .
Table 2 : Population Estimates, Water Use & Rainfal l
Year Population Total Water Us e
(acre feet)
Per Capit a
(gpcd)
Rainfall '
(inches )
2002 44,482 6,032 121 13 .08
2003 44,357 5,968 120 16.4 0
2004 44,298 6,239 126 17 .73
2005 44,687 6,098 122 16 .2 1
2006 44,559 5,999 120 14 .8 0
2007 44,433 6,493 130 6 .1 4
2008 44,579 6,359 127 15 .8 4
2009 44,829 6,134 122 18 .1 8
2010 44,948 5,489 109 33 .5 3
2011 45,418 5,285 104 21 .1 6
Ten-year per capita average 120 .1
1 . Rainfall amounts for calendar year source : Cal Poly CIMIS Weather Statio n
II . MULTI-SOURCE WATER SUPPL Y
Per WWME Policy A 2 .2 .1, the City shall utilize multipl e
water resources to meet its water supply needs . Havin g
several sources of water avoids dependence on any on e
source that may not be available during a drought o r
other water supply reduction or emergency . Maintainin g
different type sources [surface water, recycled water (fo r
irrigation), ground water] provides greater reliability an d
flexibility ; as does maintaining surface water sources i n
distinct watersheds . With the delivery of Nacimiento
mimmommomonamai m
Having several sources of water avoids
dependence on any one source that may not b e
available during a drought or other water supply
reduction or emergency
2012 Water Resources Status Report Attachment 1
Page 3
Reservoir water beginning in January 2011, the City now has five water sources, achieving the goal o f
diversifying its water supply portfolio to meet current and future community needs . The following section s
provide an overview of each water source available to the City .
Water Supply Source s
Salinas &Whale Rock Reservoirs
Salinas and Whale Rock Reservoirs have served as the City's
primary water supplies for over 50 years . The County of San Lui s
Obispo Flood Control and Water Conservation District provides th e
oversight, operations, and maintenance of the Salinas Dam an d
water delivery facilities for the benefit of the City . The City pays th e
County for the associated costs for these services . The City provide s
the oversight, operations, and maintenance of the Whale Roc k
Reservoir for the benefit of the Whale Rock Commission . The Whal e
Rock Commission is a joint powers agency made up of Cal Pol y
State University, California Men's Colony, and the City . The Cit y
draws water from these two reservoirs, as well as the Nacimient o
Reservoir, in a coordinated manner to maximize the long-term wate r
supply available from these two sources . In addition, the City has adopted policies in the WWME to account fo r
reductions in storage capacity at each lake resulting from siltation .
Nacimiento Reservoi r
The City has been involved in the Nacimiento Project planning efforts for over 15 years . Construction of the 45 -
mile pipeline and related facilities was completed in December 2010 . Water deliveries to the City's wate r
treatment plant began on January 5, 2011 . The City has a contractual right to 3,380 acre feet per year and wil l
likely maximize the use of this water source each year since the contractual amount of water cannot be carrie d
over ("banked") from year to year .
Recycled Wate r
Recycled water use for calendar year 2011 year totaled approximately 158 acre feet, up three percent fro m
153 acre feet in 2010 . During 2011, three new sites (six additional meters) were connected to the City's
recycled water distribution system to provided landscape irrigation - see Table 3 .
Table 3 : New Sites using Recycled Water in 2011 :
Sit e
Margarita Medians (3 meters)
Addres s
Margarita
~A F
1 .2
Prefumo Creek Commons (2 meters)Froom Ranch Way @ Los Osos Valley Road 4 .5
MD2 Hydrant Meter/Detention Basin Prado Road 9 .1
Total 14 .8
Three new development sites, the Olive Garden, Hampton Inn and Prado Road Streetscape, are planned t o
receive recycled water in 2012 . These new recycled water use sites are estimated to use five acre feet pe r
year.
Groundwate r
The City uses one domestic well to supplement its other water supply sources . In addition, there is a non -
potable well at the City's Corporation Yard for construction activity use . There are two additional non-potabl e
wells at the City's Laguna Lake Golf Course that provide for a portion of the golf course irrigation needs . Th e
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2012 Water Resources Status Report Attachment 1
Page 4
additional irrigation demands at the golf course are met with recycled water . Per WWME Policy A 3 .2 .3, th e
City will continue to use groundwater for domestic purposes when available, but will not consider this source o f
supply as a part of its water resources availability due to limitations for the use of groundwater resources .
Water Resource Availabilit y
Based on WWME Section 3, water resource availability to serve the community's water demand is summarize d
in Table 4 . Calendar Year 2011 water availability totaled 9,980 Acre-Feet .
Table 4 : Water Resource Availabili t
Water Resourc e
Salinas & Whale Rock Reservoirs
2011 Annual Availabilit y
6,940 AF Safe Annual Yield A
Nacimiento Reservoir 3,380 AF Dependable Yield B
Recycled Water 160 AF 2011 Annual Usage °
Siltation from 2010 to 2060 (500 AF)WWME Policy A 4 .2 .2 °
TOTAL 9,980 A F
A.Quantity of water which can be withdrawn every year while operating both reservoirs in coordinated operat i
drouaht conditions . Safe Annual Yield determined from com puter model .which accounts for siltation loss tt
WWME Policy A 4 .2 .1 )
B.Dependable Yield is the contractual amount of water the City has rights to from Nacimiento Reservoir .
C.The quantity of recycled water included is the actual prior year's recycled water usage (2011) per WWME Policy A7 .2 .2
D.Reservoir siltation is a natural occurrence that reduces storage capacity over long periods, resulting in the reduction of safe
annual yiel d
Water Su pply Accountin g
Per WWME Section 5, the City will account for water supplies necessary to meet three specific communit y
needs : 1) Primary water supply, 2) Reliability reserve, 3) Secondary water supply .
Primary Water Suppl y
The primary water supply is defined as the amount of water needed to serve the build-out population of th e
City as identified in the Land Use Element of the General Plan . The quantity of water needed for the primar y
water supply is calculated using the ten-year average of actual per capita water use, shown in Table 2, and th e
City's build-out population (57,200 per 1994 Land Use Element of the General Plan, revised 2010),per WWM E
Policy A 5 .2 .2 :
Primary Water Supply = Ten Year Average per Capita Water Use x City Build-out Populatio n
= 120 .1 gal/cap-day x 57,200 cap x 365 day/year x Acre-Ft/325,853 ga l
= 7,695 Acre-ft/yea r
Reliability Reserve
The reliability reserve provides a buffer for future unforeseen or unpredictable long-term impacts to the City's
available water supply . The quantity of water for the reliability reserve is established using twenty percent o f
the ten-year average of actual per capita water use and the existing City population (45,418, 2011 population).
The reliability reserve concept is included in the City's Charter (Section 909) which identifies that the wate r
may not be used to serve future development, and is defined per WWME Policy A 5 .2 .3 :
Reliability Reserve = Ten Year Average per Capita Water Use x 2011 City Population x 20 %
= 120 .1 gal/cap-day x 45,418 cap x 365 day/year x Acre-Ft/325,853 gal x 20 %
= 1,222 Acre-ft/yea r
Secondary Water Suppl y
The secondary water supply is the amount of water remaining from the City's available water resources above
those needed to meet the primary water supply and reliability reserve . The secondary supply is identified t o
meet peak water demand periods or short-term loss of City water supply sources, per WWME Policy A 5 .2 .4
ons under critica l
rough 2010 (pe r
2012 Water Resources Status Repor t
Page 5
Attachment 1
Secondary Water Supply Current Annual Availability — Primary Water Supply - Reliability Reserv e
= 9,980 Acre-ftiyea rA 7,695 Acre-ft/year – 1,222 Acre-ft/y r
=1,063 Acre-ft/yea rA.2011 Annual Availability
Water supply accounting is summarized in Table 5 :
Table 5: 2011 Water Supply Accounting
Total Primary Water Reliability Reserve Secondary Wate r
Supply Suppl y
9,980 AF 7,695 AF 1,222 AF 1,063 AF
III . WATER DEMAND MANAGEMEN T
The City's water conservation program is an integral part of its overall water management strategy . Th e
program has assisted in adding reliability to the water supply system over the years . In the late 1980's, the Cit y
implemented effective water efficiency programs and policies that allowed for continued community growth an d
economic development during water-constrained periods . Even with a more diversified 2011 multi-sourc e
water supply portfolio, conservation continues to play an important role considering potential water suppl y
impacts associated with climate change and regulatory requirements related to statewide water use reductio n
goals .
Taking into account changing regulatory requirements and water supply availability, the following section s
describe the shifting role of water conservation within the community and the evolution of the programs an d
services offered by the Utilities Department .
California Urban Water Conservation Council - Best Management Practices
Historically the City has utilized the California Urban Water Conservation Council's (CUWCC)Bes t
Management Practices (BMPs)as defined in the Memorandum of Understanding Regarding Urban Wate r
Conservation in California (MOU) as a guide for the City's water conservation program . The BMPs ar e
programs and services that MOU signatories agree to implement over time . Though BMPs implementation i s
voluntary, all state regulatory agencies now recognize them as the standard for compliance with State la w
(discussed below). The City has fully implemented the required measures and is thusin compliance with al l
applicable State laws .
Water Use Efficiency Legislatio n
Legislation passed over the years requires water agencies to implement water conservation measures in orde r
to be eligible for state grants, loans, or assistance . Eligibility for grants and loans apply to both water an d
wastewater projects that the City may undertake . A summary of the legislation follows :
AB 142 0
Assembly Bill 1420 (Stats . 2007, ch . 628) amended the Urban Water Management Planning Act,Water Cod e
Section 10610 et seq ., to require, effective January 1, 2009, that the terms of, and eligibility for, any wate r
management grant or loan made to an urban water supplier and awarded or administered by the Departmen t
of Water Resources (DWR), State Water Resources Control Board, or California Bay-Delta Authority, b e
conditioned on the implementation of the water Demand Management Measures (DMMs) described in Wate r
Code Section 10631(f). DWR was given discretionary authority to determine whether an urban water supplie r
is eligible for a grant or loan .
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2012 Water Resources Status Report Attachment 1
Page 6
SBx7-7
Senate Bill x7-7 was enacted in November 2009, requiring all water suppliers to increase water use efficiency .
The legislation sets an overall goal of reducing per capita urban water use by 20 percent by December 31 ,
2020 . The law directs incremental progress towards this goal by reducing per capita water use by at least te n
percent by December 31, 2015 .
The law states :
Each urban retail water supplier shall develop water use targets an d
an interim water use target by July 1, 2011 .
An urban retail water supplier shall include in its water managemen t
plan, due July 2011, the baseline daily per capita water use, wate r
use target, interim water use target, and compliance per capit a
water use .
Table 6 : 2015 and 202 0
Target s
Year Adjusted Pe r
Capita Targe t
2015 120 gpcd .
117 gpc d
Effective 2016, urban retail water suppliers who do not meet th e
water conservation requirements established by this bill are not eligible for state grants or loans .
The City's UrbanWater Management Plan provides a complete discussion of the legislative requirements .
Table 6 summarizes the per capita targets the City must meet in order to be in compliance with the law .
Urban Water Management Planning Ac t
Initially passed in 1984 and amended several times over the years, the Urban Water Management Plannin g
Act requires water agencies to report on their progress in implementing Water Demand Management
Measures outlined in the law . The law was amended so that full implementation of the BMPs would b e
accepted as being in compliance with the part of the law . The City's 2010 Urban Water Management Plan
provides a complete discussion of the City's water conservation program and verification of compliance wit h
the regulations of the act .
Other Regulatory Requirements
The Clean Water State Revolving Fund Requirement s
In order to qualify for a loan for any water or wastewater project from the State Water Resources Control Boar d
an agency must provide verification that it is in compliance with either the Demand Management Measures i n
the Urban Water Conservation Planning Act or the CUWCC BMPs .
2011 Water Conservation Program Highlight s
Residential and Commercial Technical Assistanc e
The most important program the Utilities Conservation Section offer s
is its technical assistance and support to the community . During 201 1
the section responded to approximately 1,860 requests for assistanc e
with high water bill, leak detection assistance, and general 1,860 requests for assistance in 201 1
consultations regarding customer billing problems . The requests fo r
consultations are typically received from people experiencing hig h
water bills, residents participating in the low income assistanc e
program, or customers requesting a utility bill adjustment through the Utility Billing Adjustment Committee .
Water audits often reveal problems which are then corrected by the property owner resulting in lower water us e
and reduced water bills . In addition, the section processed approximately 400 utility billing adjustment request s
during 2011 .
Utilities Conservation responded t o
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2012 Water Resources Status Report Attachment 1
Page 7
Public Information &Educatio n
In an ongoing effort to educate the public, the City provides informationa l
brochures on a variety of water conservation, water quality, energ y
conservation, and recycling topics upon request . Additionally, a quarterl y
newsletter is produced which focuses on current information regarding water ,
wastewater, stormwater, and solid waste issues . The newsletter is mailed t o
approximately 21,000 households . Additional information has been distribute d
through paid media advertising, public service announcements, an d
participation at Farmer's Market, home shows, etc .
The Utilities Department continues to offer a water education program withi n
San Luis Coastal Unified School District . The program targets third through fift h
grade students and compliments the study of water within the School District's
existing curriculum . Teachers have been enthusiastic about the program ,
particularly with the field trip to the Water Reclamation Facility .
IV.PROJECTED WATER SUPPLY SITUATIO N
Reservoir Storage Curve
The Reservoir Storage Curve is integral to the City's annual water resource analysis . It is based on a computer
model used to estimate the City's future reservoir storage in Salinas and Whale Rock Reservoirs, utilizin g
historical drought weather patterns, water use projections, reservoir data, and available water supplies fro m
Nacimiento Reservoir, recycled water, and limited groundwater . Figure 5 shows the Reservoir Storage Curve . Th e
model assumes implementation of Stage I conservation when supplies are projected to last only three years .
Stages II and III conservation measures are implemented when water supplies are estimated to last only tw o
years and one year, respectively (as shown on Figure 5). The model was updated to reflect the City's curren t
water storage and assumptions relative to water demands .
Assuming the onset of an extended drought, the model predicts current water supplies will last into the year 202 4
until Whale Rock and Salinas reservoirs are drawn down to minimum pool . (Figure 5).
V.SUMMAR Y
As of June 01, 2012, the City's surface water supplies from Salinas and Whale Rock Reservoirs are at 73% o f
maximum storage . Even with these available supplies, the community must continue to utilize water in an efficien t
manner to meet the State's requirement for reducing urban water use . With the multi-source water policy, includin g
the delivery of Nacimiento water in 2011, the City has implemented a long-term strategy which will ensure a
reliable supply of water to meet the current and future needs of the community .
Attachments :
1 . Definitions & Informatio n
2 Figure 1
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Definitions &Informatio n
Safe Annual Yield :
The maximum quantity of water which can be delivered from the water source eac h
year during a critical dry period (i .e . historical drought period).
Minimum Pool :
Minimum amount of water in Whale Rock or Salinas Reservoirs below which water
deliveries must be stopped . This amount is established at 2,000 acre feet which i s
left in the reservoirs to support aquatic habitat and other wildlife .
Acre foot :
*1 acre foot = 325,851 gallon s
*Enough water to cover a football field with 1 foot of wate r
*Enough water to serve approximately 4 average single family homes in Sa n
Luis Obispo) per yea r
Gallons per Capita per Day (gpcd):
Calculation =Total Acre Feet x325,85 1
City Population x 36 5
Water Demand (acre feet per year):
Calculation =gpcd x Current City Population x 36 5
325,85 1
Salinas Reservoir :
Maximum Storage Capacity = 23,842 .9 acre feet
Minimum Pool = storage amount when water extractions must cease = 2,00 0
acre fee t
Surface Area = 730 acre s
Drainage Area = 112 square miles = 71,700 acre s
Whale Rock Reservoir :
Maximum Storage Capacity = 40,662 acre feet
Minimum Pool = storage amount when water extractions must cease = 2,00 0
acre fee t
Surface Area = 594 acre s
Drainage Area = 20 .3 square miles = 13,000 acres
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Figure 1
City of San Luis Obisp o
Reservoir Storage Curv e
45,00 0
40,000
35,00 0
30,00 0
15,00 0
10,00 0
5,000
0
Modeled Drough t
I
r
Stage I
Stage II Stage II I
V
Combined Salinas & Whale Rock Reservoirs Minimum Pool : 3,100 acre fee t
(I V I I I IT I I T ITT I R 1 fTTT R F l I E I I ITTnT I I I TTT"i h I I R T"1 1-I n I I I I r1T11 ITI -1 I n mm 11 1 I Il 1 1 n-I V I I I I-T I I r1 l ITl I rl I I I I I R i IT I I I T I I rl I I T I I rl I R I I rl I I Tl I! I I IT 1 1 11 I ITI 1
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