HomeMy WebLinkAbout05/16/2000, 5 - AMENDING THE GENERAL PLAN WATER AND WASTEWATER MANAGEMENT ELEMENT POLICIES RELATIVE TO SILTATION AND SAFE ANNUAL YIELD council M "Dw
May 16, 2000
j acEnaa Report 5
C I T Y OF SAN LUIS OBISPO
FROM: John Moss, Utilities Director
Prepared By: Gary W. He son, Water Division Manager
SUBJECT: AMENDING THE GENERAL PLAN WATER AND WASTEWATER
MANAGEMENT ELEMENT POLICIES RELATIVE TO SILTATION
AND SAFE ANNUAL YIELD
CAO RECOMMENDATION
Approve the Planning Commission's recommendation to adopt a resolution to amend the Water
and Wastewater Management Element of the General Plan to annually account for reductions in
safe annual yield due to siltation and approve a negative declaration of environmental impact.
DISCUSSION
On December 13, 1999, the City Council discussed amendments to certain water policies in the
General Plan Water and Wastewater Element. The modifications clarified certain water related
policies and had been discussed by the Planning Commission prior to the Council meeting. The
Planning Commission's recommendations were included in the recommended amendments
which were adopted by Council following the public hearing.
During Council discussions relative to these modifications, questions were raised as to how
siltation at the reservoirs is accounted for in the polices. Council directed staff to prepare an
analysis of siltation impacts at the reservoirs and potential amendments to current policies to
account for the loss of safe annual yield due to siltation.
This report will discuss the impacts to the City's water resources due to siltation and alternatives
for accounting for these losses. In addition, the report will discuss the computer model used for
estimating safe annual yield. The data in-the computer model has been updated based on
corrected information which has resulted in a minor change to previous safe annual yield
estimates. The recommended policy changes were presented to the Planning Commission on
April 12, 2000 and the Commission concurred with the proposed modifications as shown in
Attachment A to this report.
Siltation
Siltation in reservoirs is a natural occurrence and can impact the storage capacity over a long
period. The reduction in storage capacity reduces the safe annual yield from the reservoirs. This
issue is discussed in detail in Section 5.1 of the Water Management Element. The computer
model used to estimate safe annual yield can also be utilized to evaluate impacts due to siltation.
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Council Agenda Report—Water Management Element Policy Changes
Page 2
The maximum storage capacity of the lakes is one of the input values and these storage amounts
can be adjusted to reflect reduced storage capacity estimates.
A number of reports have been prepared on the Salinas Reservoir to estimate the maximum
storage capacity and the siltation rates that are occurring over time. In 1990 when Salinas
Reservoir was nearly dry, an aerial survey of the lake was prepared which updated the storage
capacity and provided estimates of siltation since the dam was constructed. Based on these latest
figures, the average loss of storage capacity for Salinas Reservoir is estimated to be 40 acre feet
per year.
Whale Rock Dam construction was completed in 1961 and had an original estimated storage
capacity of 40,660 acre feet. There have been no siltation studies or subsequent aerial surveys
performed since completion of the dam. The watershed above Whale Rock Dam is
approximately 20 square miles as compared the Salinas Dam watershed of 112 square miles.
This one factor could indicate that siltation at Whale Rock reservoir would be less than Salinas
but other factors such as soil type, steepness of the watershed, rainfall intensity, etc. can also
influence the amount of siltation that occurs over time. It should be noted that the area above
Whale Rock Reservoir is prone to landslides which has the potential to increase siltation rates.
Since no information is available to indicate what rate of siltation is occurring at the Whale Rock
Reservoir, it is assumed for planning purposes that the annual average rate of siltation is similar
to Salinas Reservoir.
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 forward. However, since Whale Rock'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 dam was constructed in 1961. Based on these assumptions,
the current estimated storage capacity at Salinas and Whale Rock, for the year 2000, are 23,433
acre feet (af) and 39,100 of respectively. Based on these reduced storage values, the safe annual
yield computer model projects a total loss of 250 acre feet of safe annual yield from the
reservoirs as a result of past siltation.
Based on the assumed siltation rates previously discussed, the total storage capacities at Salinas
and Whale Rock in the year 2025 would be reduced to 22,443 of and 38,100 of respectively.
Based on these storage capacities, an additional 250 afy of yield would be lost between the year
2000 and 2025. This equates to 10 acre feet per year of combined loss of safe annual yield from
Salinas and Whale Rock reservoirs.
Accounting for Siltation
The.current policies in the Water Management Element identify the loss of 500 acre feet per year
(afy)of safe annual yield as a result of siltation to the year 2025. The 500 afy is identified as one
of the components of additional water supplies that the city needs to develop. This method of
accounting for siltation does not account for the losses as they occur over time. It should be
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Council Agenda Report—Water Management Element Policy Changes
Page 3
noted that siltation does not occur in a constant manner each year, and siltation can be
accelerated following large fires or floods in the watershed.
Safe Annual Yield Computer Model
The City of San Luis Obispo utilizes a computer model which was developed in the late 1980's,
and updated in 1996, to estimate the safe annual yield from the coordinated operation of the
City's available water resources (Salinas and Whale Rock reservoirs, and groundwater). The
model uses historical rainfall, evaporation, inflow, and downstream releases to evaluate the
maximum amount of water that can be delivered to the City every year during the critical drought
period of record. The actual historic data for the model begins in 1943 for Salinas Reservoir and
1961 for Whale Rock. Data for Whale Rock was estimated back to 1943 based on correlations
between Salinas and Whale Rock historic information.
The data for the model relative to Salinas Reservoir was input from the monthly reports prepared
by the County of San Luis Obispo and kept on file in the City's Utilities Administration Office.
During preparation of analysis relative to the impacts of the Salinas Reservoir Expansion Project
on downstream flows in the Salinas River, an error in the input data was discovered. Once this
data was discovered and corrected, the computer model now estimates an additional 55 acre feet
per year (afy) of safe •annual yield beyond the previous figure of 7,735 afy (which includes
groundwater). This amount should be updated in the Water Management Element.
Recommendation
Modify the policies to account for the loss of safe annual yield due to siltation to date (250 acre
feet) and then account for the siltation each year. This will initially reduce the water available
for development by 250 acre feet and by 10 acre feet each year thereafter. This alternative and
its implications to water availability are shown on Figure 1 (Attachment B). Figure 1 illustrates
projected water demand based on a one percent growth rate and indicates when new water supply
projects are projected to be available.
Staff recommends that this alternative be selected and that the safe annual yield figure be adopted
for each specific year starting with the year 2000 (as shown in the table below). The safe annual
yield figure for 2000 includes the 55 acre foot adjustment due to the data error and losses due to
siltation that have occurred to date. The water available for development will be updated each
year in the annual Water Resources Status Report and will take into account updated population
estimates.
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Council Agenda Report—Water Management Element Policy Changes
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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 6,090 acre feet 500 acre feet 7,490 acre feet
2006 6,080 acre feet 500 acre feet 7,480 acre feet
2007 6,070 acre feet 500 acre feet 7,470 acre feet
2008 6,060 acre feet 500 acre feet 7,460 acre feet
2009 6,050 acre feet 500 acre feet 7,450 acre feet
Summary
The policies in the Water Management Element of the General Plan should be modified to reflect
impacts due to siltation annually as identified in the recommendation above. In addition,the safe
annual yield estimates should be updated to reflect the current revised data which increases the
safe annual yield by 55 acre feet. The specific revisions to the Water Management Element
necessary to implement the recommended policy changes are shown in legislative draft in
Esh'l b + A.
CONCURRENCES
■ Staff and the Planning Commission recommend approval of the negative declaration. No
comments were received on the negative declaration.
■ The Planning Commission concurs with the recommended policy changes as shown in
Attachment A.
FISCAL IMPACTS
There are no fiscal impacts associated with the recommended policy changes.
ALTERNATIVES
The policy could be modified to account for all of the siltation losses which are projected to the
year 2025. This would reduce the water available for development by 500 acre feet per year and
is graphically shown on Figure 2 (Attachment 3).
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Council Agenda Report—Water Management Element Policy Changes
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This alternative would have significant impacts relative to additional annexations and would
likely preclude any additional annexations until new water resources are developed. This
alternative is not recommended as it may be inappropriately restrictive, could preclude
annexation and development at a time when water is actually available for allocation, and fails to
recognize the City's efforts, intent, and likelihood of developing additional water supplies.
Attachments:
1. Resolution Adopting Water Management Element Policy Changes
2. Figure 1: Recommendation for Accounting for Siltation
3. Figure 2: Alternative for Accounting for Siltation
4. Initial Study (ER 41-00)
5. Draft Planning Commission Meeting Minutes of April 12,2000
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,h�TA[1-1fV1Erl i 1
RESOLUTION NO. (2000 Series)
A RESOLUTION OF THE COUNCIL OF THE CITY OF
SAN LUIS OBISPO APPROVING A NEGATIVE DECLARATION
OF ENVIRONMENTAL IMPACT AND AMENDING THE
WATER MANAGEMENT ELEMENT OF THE GENERAL PLAN
WHEREAS, the Planning Commission conducted a public hearing on April 12, 2000 and
recommended approval of amendments to the City's Water Management Element of the General
Plan; and
WHEREAS, the City Council conducted a public hearing on May 16, 2000 and has
considered testimony of other interested parties, the recommendation of the Planning
Commission, and the evaluation and recommendation of staff; and
WHEREAS, staff and Planning Commission have recommended a negative declaration
of environmental impact associated with the recommended policy revisions; and
WHEREAS, the City Council, after considering the draft documents and staff's analysis,
the Planning Commission's recommendations, and the public testimony, finds that the amended
sections are consistent with the General Plan.
BE IT RESOLVED by the Council of the City of San Luis Obispo hereby approves:
SECTION 1. Environmental Determination. The City Council finds and determines that
the project's Negative Declaration adequately addresses the potential environmental impacts of
the project, and reflect the independent judgment of the City Council. The Council determines .
that the amendment will have no significant effects on the environment. The Council hereby
adopts said Negative Declaration.
SECTION 2. Policy 1.1.2 (section numbers refer to the Water Management Element of
the General Plan) of the Water Management Element is hereby amended to modify the safe
annual yield to annually account for losses due to siltation (specific changes shown in Exhibit A
to this resolution).
SECTION 3. The "Background" portion of Section 1 is hereby amended to be consistent
with the amendment to Policy 1.1.2 (Exhibit A).
SECTION 4. The "Background" portion of Section 5 is hereby amended to clarify the
policy relative to accounting for siltation as it occurs at Whale Rock and Salinas Reservoirs
(Exhibit A).
SECTION 5. The`Background"portion of Section 6 is hereby amended to be consistent
with previous amendments discussed above (Exhibit A).
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Resolution No. (2000 Series)
Page 2
Upon motion of seconded by
and on the following roll call vote:
AYES:
NOES:
ABSENT:
the foregoing resolution was adopted this day of 2000.
Mayor Allen Settle
ATTEST:
Lee Price, City Clerk
APPROVED AS TO FORM:
I/gepll,, Attorney
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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 amountbased 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 aT..\lal yield is 7,735 ante feet, baser) en 7,235 os.-e_fee} fir-om the n e;dinmed
The
City's safe annual yield from the coordinated operation of Salinas and Whale Rock Reservoirs and
500 acre feet of groundwater are shown in Table 1 below. The safe annual yield includes reductions
due to siltation at the reservoirs which is discussed in more detail in Section 5.0.
1.13 Groundwater
A. The amount of groundwater which the City will rely upon towards safe annual yield is
identified in policy 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 whetherreductionor cessationofpumping
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 which could be met
during the most severe drought for which records are available.
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City of SLO General Plan Water&Wastewater Management Element
The safe annual yield of an individual source of water supply is defined as the quantity of water
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.
TheT{, d 4 d safe,anaug yield st• ..te,o f;,235 aGrn_Fnn«(from r»rfnno rr wr—G-es)uses the eentmlling
'l p Q(a, �• . l
drought period 1996 to 1-991. flaSSmfV Y i-m!yield
iel estimate
was adopted I
]3'92 93 Water. ?prati6nal Plan. TL. adopted safe aanunl yield f-em 9-aline end Whales RAaU_
Rese,Fveks, inelu4ingcan aGre. f «ofgr-.,,nd.,ester- is 7,735 asm, &et per-5, 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
Water Supply Sour Safe Ann d
Coordinated Operations of the�Si and 35 acre-feet
Whale Rock Reservoirs
Groundwater 50 -feet
TOTAL ANNUAL YIELD 7,735 acre-feet
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City of SLO General Plan Water&Wastewater Management Element
TABLE I
SAFE ANNUAL YIELD
Year =Salinas &Whale `.' �tGroundwater,- '_ `:'Total
aJRock Reservoi s:, ._ x. _ f_:, :`.`' . _A_ ._
2000 v ` 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 6,090 acre feet 500 acre feet 7,490 acre feet
2006 6,080 acre feet 500 acre feet 7,480 acre feet
2007 6,070 acre feet 500 acre feet 7,470 acre feet
2008 6,060 acre feet500 acre feet 7,460 acre feet
2009 6,050 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
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 effort to 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 operationof
the reservoirs. The report "Coordinated Operations Study for Salinas and Whale Rock reservoirs"
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City of SLO General Plan Water&Wastewater Management Element
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. , mduGing the safe annual yiel
7.235 acre fee 4 .1 r'f 4-he r-oyieus sees-ion fns thg n„ernni c:fP w lal field
an- ysis
Groundwater Resources
The groundwater basin which 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. Since 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 conjunctiveuse
of the groundwater basin and surface water supplies in this manner will provide an effective
management strategy which 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 treatmentwhich
reduces costs compared to surface water supplies. Even with treatment for nitrates and PCE, the
projected costs associated with that treatment show groundwater to be comparable to other
alterative 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.
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City of SLO General Plan Water& Wastewater Management Element
5.0 SILTATION AT SALINAS AND WHALE ROCK RESERVOIRS
5.1 POLICY
5.1.1 Accounting for Siltation
The, City Shall de-3.101op 5QQ RPM 480t CA& A
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 occurrencewhich can substantiallyreduce 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 estirnatedthat the siltation
rate was approximately 82 acre-feet per year. The latest 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
1 '+effis which need to be assumed+ estimate Fo.i,..4GH in f apmual 541d aFe the 1
siltatim; Fate, and the hiturn date for the,estimate TC+" Aata Aqqllmad
to be 416 year-2Q
th� i
@n a-eGAain 1 s r-S-�r-9 Ann 1 laean b 1 1 +ell using City'sGempute....+8.7e1 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 reservoirs siltationhas
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City of SLO General Plan Water&Wastewater Management Element
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.
TABLE 5
SALINAS RESERVOIR CAPACITY STUDIES
Total Usable Avg Annual Loss
Year Agency Capacity Capacity Usable Capacity
(acre-feet) (acre-feet) (acre-feet/year)
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 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.
145ing a planning her-iZen to the, year-2025, there, ;AQ1 be, -an esti-m-amed ]Ass of ster-agG GapaGity a4
Salinas and I_A.1h;i1P Ronk mseFvoiFs 41,400 aere feet and 2,560agm-faigrespeGtively.
StGr-aff GapaGity r-@dUGtieB�thG_-_M_v.4-11 be a—a @A_imated m--dur-69a in the,City's safe apauaI54eldefiQ
amen-writ v.zhem delermipAag if tke Gk3, has adequate water- supplies to raeot fi-ib—ire *.rate-F darnand
A-AWN M.ra-UR: ISUPPly PROjeCAS 404-11 BA-GE-1 W MA—k-e-,Up fer-thig !Oss in safe annii—al yield.
The estimated loss to storage capacty.for Salinas Reservoir between 1990 and 200.0 is-400'
s 400 acre feet.
The estimated loss at Whale Rock Reservoir between 1961 and 20001.s i 566 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.
FIGIIRR T
C AFF_ A ATTaTT T A i 3Aq T D D 1;DI ICTION DIM TO S11 T A TT/lAT
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City of SLO General Plan Water&Wastewater Management Element
Reduction of Combined Reservoir Yield (acre-feet per year)
-200
...........
300
is
-400
J
-500
7
600
-700
201 0 2025 2030 2035 2040 2045 050
Years
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City of SLO General Plan Water&Wastewater Management Element
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
of the water and other environmental impacts, total and unit costs, reliability, water quality,
development time, and quantity available.
6.13 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 1-1,596 9,096 acre-feet. This figum inGludes the 2,909aere
Table 7 shows the build-out waterrequirement,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 day per capita) of Total
Existing Development 43,415 7,052 77.5%
New Development 12,585 2,044 22.5%
TOTAL 56,000 9,096 100.0%
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City of SLO General Plan Water&Wastewater Management Element
TABLE 7
NEW WATER SUPPLY REQUIREMENTS
Component acre-feet
Required Safe Annual Yield 9,096
Safe Annual Yield as of 2000 7,540
Additional Safe Annual Yield Required
(based on per capita water demand ratios) 1,556
Reliabili Reserve 2,000
Siltation 2000 to.2025 250
Total Additional Water Supply Requirement 31806
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 be greaterreliabilityand
flexibility if sources are of different types(such as surface water and groundwater)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
15 5-16
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5-18
Attachment I
INITIAL STUDY
ER 41-00
ENVIRONMENTAL CHECKLIST FORM
1. Project Title: Water &Wastewater Management Element Amendment for Siltation Accounting
2. Lead Agency Name and Address: City of San Luis Obispo
990 Palm Street
San Luis Obispo CA 93401-3249
3. Contact Person and Phone Number: Glen Matteson, Associate Planner
805 781-7165
e-mail: gmatteso@slocity.org
4. Project Location:
The proposed text change would affect management in the City of San Luis Obispo.
5. Project Sponsor's Name and Address:
City of San Luis Obispo
Utilities Department (Gary Henderson)
955 Morro Street
San Luis Obispo, CA 93401
6. General Plan Designation:
7. Zoning:
The change mainly affects developable land inside the City's urban reserve line.
8. Description of the Project:
The City obtains nearly all its water from Salinas Reservoir and Whale Rock Reservoir.
These reservoirs accumulate silt, as streams from surrounding watersheds deposit
sediment in them faster than releases or withdrawals remove it. As the silt accumulates, it
reduces the storage capacities of the reservoirs. In tum, reduced storage capacity means
lower "safe yield," which is the amount the City can rely on withdrawing year after year,
even under drought conditions.
As part of its General Plan, the City has adopted policies concerning acquisition, use, and
conservation of water supplies. The City has recognized that siltation is reducing the yield
of its reservoirs. Much of the City's planning policy is based on an interval of about 30
years, extending from 1995 to 2025. As a result, Policy 5.1.1 calls for the City to develop
500 acre-feet of safe yield, beyond amounts identified for other purposes, to account for
yield reductions due to siltation to the year 2025. The policies also call for obtaining 1,361
acre-feet to support build-out consistent with the General Plan Land Use Element, plus
5-19
4
2,000 acre-feet for a reliability reserve. Adding these amounts to the currently identified
safe yield of 7,735 acre-feet would result in a total future water supply of 11,596 acre-feet
(safe annual yield).
In 1999, the City Council approved clarifications of the water policies, mainly concerning
allocation of safe yield to new development. Each year, the yield needed to meet the
planned per-person usage of the current city population will be subtracted from the safe
yield. The difference will be the amount available for allocation to new development. Until
essentially all fixtures in the city have been replaced with low-flow fixtures, each new
development must retrofit fixtures to offset twice its projected water usage.
During consideration of the 1999 amendments, the City Council asked staff to prepare for
hearings an amendment that would account annually for reductions in safe yield. That
amendment is the subject of this initial study. The amendment would result in subtracting
250 acre-feet from the identified safe yield, to account for past reductions, and ten acre-
feet each year in coming years. Also, the safe annual yield estimate is proposed to be
corrected by adding 55 acre-feet, following discovery of a data error in previous modeling.
9. Project Entitlements Requested:
Approval of an amendment to the text of the General Plan Water and Wastewater
Management Element.
10. Surrounding Land Uses and Setting:
The proposed amendment may affect the rate of development within in all areas that the
Land Use Element shows for urban uses.
11. Other public a9encies whose approval is required:
None.
2 5-20
ENVIRONMENTAL FACTORS POTENTIALLY AFFECTED:
This project would potentially affect the environmental factors checked below, involving at
least one impact that is a "Potentially Significant Impact" as indicated by the checklist on the
following pages.
Land Use and Planning Biological Resources Aesthetics
Population and Housing Energy and Mineral Cultural Resources
Resources
Geological Problems Hazards Recreation
Water Noise Mandatory Findings of
Significance
Air QualityPublic Services
Transportation and Utilities and Service `-
Circulation Systems
FISH AND GAME FEES:
There is no evidence before the Department that the project will have any potential adverse effects on
ILS' fish and wildlife resources or the habitat upon which the wildlife depends. Therefore, the project qualifies
for a de minimis waiver with regard to filing Fish and Game fees.
The project has potential to impact fish and wildlife resources and shall be subject to the payment of Fish
and Game fees pursuant to Section 711.4 of the California Fish and Game Code.
3 5-21
DETERMINATION:
On the basis of this initial evaluation:
I find that the proposed project could not have a significant effect on the environment, and a X
NEGATIVE DECLARATION will be prepared.
I find that although the proposed project could have a significant effect on the environment, there will
not be a significant effect in this case because the mitigation measures described on attached sheets
will be part of the project. A MITIGATED NEGATIVE DECLARATION will be prepared.
I find that the proposed project may have a significant effect on the environment, and an
ENVIRONMENTAL IMPACT REPORT is required.
I find that the proposed project may have one or more significant effects on the environment, but at
least one effect(1) has been adequately analyzed in an earlier document pursuant to applicable legal
standards and (2) has been addressed by mitigation measures based on the earlier analysis as
described on attached sheets, if the effect is a "Potentially Significant Impact' or is "Potentially
Significant Unless Mitigated." An ENVIRONMENTAL IMPACT REPORT is required, but it must
analyze only the effects that remain to be addressed.
I find that although the proposed project could have a significant effect on the environment, there will
not be a significant effect in this case because all potentially significant effects (1) have been
analyzed in an earlier EIR pursuant to applicable standards and (2) have been avoided or mitigated
pursuant to that earlier EIR, including revisions or mitigation measures that are imposed upon the
proposed project.
I find that the proposed project may have one or more significant effects on the environment, but(1)
the potential impacts have been adequately analyzed in an earlier environmental impact report
pursuant to applicable legal standards, including findings of overriding considerations for some
potential cumulative impacts, and (2) impacts for which findings of overriding considerations have not
previously been made have been avoided, or mitigated by measures described on attached sheets.
Arnold Jonas, Community Development Director
BY:
Signatu Date
Joh andeville, Long-range Planning Manager
4 5-22
EVALUATION OF ENVIRONMENTAL IMPACTS:
1. A brief explanation is required for all answers except "No Impact" answers that are adequately supported by
the information sources a lead agency cites in the analysis in each section. A "No Impact" answer is
adequately supported if the referenced information sources show that the impact simply does not apply to
projects like the one involved (for example, the project falls outside a fault rupture zone). A "No Impact"
answer should be explained where it is based on project-specific factors as well as general standards (for
example, the project will not expose sensitive receptors to pollutants, based on a project-specific screening
analysis).
2. All answers must take account of the whole action involved, including impacts that are off-site as well as on-
site, cumulative as well as project-level, indirect as well as direct, and construction as well as operational.
3. "Potentially Significant Impact' is appropriate if there is substantial evidence that an effect is significant. If
there are one or more "Potentially Significant Impact' entries when the determination is made, an EIR is
required.
4. "Potentially Significant Unless Mitigation Incorporated" applies where the incorporation of mitigation measures
has reduced an effect from "Potentially Significant Impact" to a "Less than Significant Impact" The lead
agency must describe the mitigation measures, and briefly explain how they reduce the effect to a less than .
significant level (mitigation measures from Section 17, "Earlier Analysis,"may be cross-referenced).
5. Earlier analysis may be used where, pursuant to the tiering, program EIR, or other CEQA process, an effect
has been adequately analyzed in an earlier EIR or negative declaration. Section 15063 (c) (3) (D). Earlier
analyses are discussed in Section 17 at the end of the checklist.
6. Lead agencies are encouraged to incorporate into the checklist references to information sources for potential
impacts (such as general plans, zoning ordinances). Reference to a previously prepared or outside document
should, where appropriate, include a reference to the page or pages where the statement is substantiated. A
source list should be attached, and other sources used or individuals contacted should be cited in the
discussion.
5 5-23
• 4-i rnc.n�tvz--�- g-
Issues and Supporting Information Sources Sources Potentially Potentially Less Than No Impaa
Significant Significant Significant
Water Poli Amendment for Siltation Issues Mites Impact
Policy Mitigation
-
Incorporated
1. LAND USE AND PLANNING- Would the proposal:
a) Conflict with a General Plan designation, specific plan X
designation, or zoning?
b) Conflict with applicable environmental plans or policies 1 X
adopted by agencies with jurisdiction over the project?
c) Be incompatible with existing land use in the vicinity? X
d) Affect agricultural resources or operations (such as impact
to soils or farmlands, or impacts from incompatible land X
uses)?
e) Disrupt or divide the physical arrangement of an
established community (including a low-income or minority X
coirimun' ?
The amendment will not conflict with policies on land use, growth masa emer or resource conservation.
2. POPULATION ANDMOUSING=Would the. ro osal:
a).' Cumulatively exceed official regional or local .population X
projections?
b) Induce substantial growth in an area either directly or
indirectly(for example,through projects in an undeveloped X
area:or major infrastructure)?
c DigOtac6existinq housing, especially affordable housing? X
3.'GEOLOGIC PROBLEMS. Would the•proposal result in io expose people to potential impacts.involvin :
a) Fault rupture? X
b) Seismic ground shaking? X
c) Seismic ground failure, including liquefaction? X
d) 'Seiche,tsunami, or volcanic hazard? X
e) Landslides or mudflows? X
f) Erosion, changes.in topography or unstable soil conditions X
from excavation,grading, or fill?
g) Subsidence of the land? X
h) Exparisive soils? X
i Uni ue:geologicor physical features? X
4..WATER: Would.t:he ro osal;result:.in:
`changes a.vabsorption rates,:dra'inage-patterns, or the rate X
and.amount of surface runoff?
Exposure of people or property-to water related hazards such X
as flooding?
a) Discharge into surface waters or other alteration of surface
water quality(including temperature, dissolved oxygen or X
turbidity)?
b) Changes in the amount of surface water in any water X
body?
C) Changes in currents, or the course or direction of water X
movements?
d) Change in the quantity of ground waters, either through
direct additions or withdrawals, or through interception of X
an aquifer by cuts or excavations or through substantial
loss of groundwater recharge capability?
e Altered direction or rate of flow of roundwater? X
6 5-24
Issues and Supporting Information Sources Sources Potentially Potentially Less Than No Impact
Significant Significant Significant
Water Poli Amendment for Siltation Issues less Impact
� MMitigation
incorporated
f) Impacts to groundwater quality? X
g) Substantial reduction in the amount of groundwater X
otherwise available for public water supplies?
5. AIR QUALITY. Would the proposal:
a) Violate any air quality standard or contribute to an existing
or projected air quality violation (noncompliance with X
APCD Environmental Guidelines)?
b) Expose sensitive receptors to pollutants X
c) Alter air movement, moisture, or temperature, or cause X
any change in climate?
d Create,ob•ectionable odors? FX
6. TRANSPORTATION/CIRCULATION. Would.the proposal result in:
a) increased vehicle trips-ortraffic congestion? X
b) Haards to safety from.design features(such as sharp
curves or dangerous intersections) or incompatible uses X
(such as:farm equipmerit)?
C) Inadequate.general:or emergency access? X
d) Insufficient:paMng capacity on-site or off-site? X
e) Hkirds.or::barriers for ped
Conflicts westriansorbicyclists? X
f) ith adopted policies supporting altemative X
transpgtion.(such as bus turnouts, bicycle racks)?
g) Rail.,i0Mterbome or air.traffic impacts(incompatibility with X
Ai•• rt Land Use Plan
7. :BIOLOGICAL RESOURCES. Would.the proposall. ffect:
a) 'Rndangered, threatened.or rare species or their habitats X
(ir duding'planfs; fish; insects, animals.orbirds)?
b) .Locatly.designated zspecies(such as heritage trees)? X
c) Lbcdfl-designated natuial communities(such as oak X
#o est 'coaVe ibabitat)? .
d) HNetland habitat{marsh;riparian.and vemal pool)? X
41§). `Wildllfeiis rsal>ortmi rationcarridors?' X
8. ENERGY AND MINERAL RESOURCES. Would the ro osal:
a) Conflict with-adopted energy:conservation plans? X
b) Use non-renewable resources wastefully or inefficiently? X
c) Result in the loss of availability of a known mineral X
resource that would be of future value to the region and
the.residents of the State?
9. HAZARDS. Would the proposal involve:
a) A risk of accidental explosion or release of hazardous
substances (including oil, pesticides, chemicals or X
radiation)?
b) Possible interference with an emergency response plan or X
emeMency evacuation Ian?
5-25
Issues and Supporting Information Sources Sources Potentially Potentially Icss Than No Impact
Significant Significant Significant
Unless
Water Policy Amendment for Siltation Issues
Mitigation impact
Incorporated
c) The creation of any health hazard or potential health X
hazard?
d) Exposure of people to existing sources of potential health X
hazards?
e) Increased fire hazard in areas with flammable brush, grass X
or trees?
10. NOISE. Would the proposal result in:
a) Increase in existing noise levels? X
b) Exposure of people to"unacceptable" noise levels as X
defined by the San Luis Obispo General Plan Noise
Element?
11.PUBLIC ZERVICES. Would the proposal have an effect upon,or-result in a need for new or altered
government services in an of the.followin areas:
a) Fire.protection? X
b) Police protection? X
c) Schools? X
d) Maintenance of public facilities, including roads? X
e Other governmental services? X
12.UTILITIES AND SERVICE SYSTEMS. Would the proposal result in a need for new systems or supplies,
ors ustantial alterations to thb followin utilities:
a) Power or natural gas? X
b) Communications systems? X
cj Local or regional water treatment or distribution facilities? X
d) Sewer or septic tanks? X
e) Storm water drainage? X
f) Solid waste disposal? X
Local or regional Water supplies? 1 X
The amendment would result in there being less water available for allocation to development.projects,
and a slightly higher level of reliability for existing water users, until additional water sources are obtained,
when the affect would be moot for at least several decades.
The City's year 2000 population is estimated to be about 43,000. At the per-person planning rate of 145
gallons per day, the annual water usage would be 6,984 acre-feet Under the adopted policy, the amount
available for new development would be 7,790 (corrected from 7,735) minus 6,984, or 806 acre-feet. With
adoption of the annual accounting approach, safe yield would be reduced by 250 acre-feet, to account for
losses to date; the amount available for new development would be 556 acre-feet. Since less safe yield
could be allocated to new development, in principle the actual supply reliability for existing customers
would be higher. However, by adopted policies that are not proposed to change, development projects
cannot proceed until they offset their water usage (resulting in no net increase), so the affect is negligible.
The amendment's affects would be further reduced by the City obtaining additional supplies. With adopted
policies that are not proposed to change, one-half of the yield from new water-supply projects will go to the
reliability reserve and one-half will be available for new development. The City expects the Water Reuse
Project to increase safe yield by 1,200 acre-feet, by the year 2003. The Salinas Reservoir Expansion
Project would add 1,650 acre-feet. The Nacimiento Project would provide the total future requirement that
has been identified.
8 5-26
Issues and Supporting Information Sources Sources Potentially Potentially Lass Than No Impact
Significant Siinificant Significant
Water Poli Amendment for Siltation Issue unless Impact
� Mitigation
Incorporated
13.AESTHETICS. Would the proposal:
a) Affect a scenic vista or scenic highway? X
b) Have a demonstrable negative aesthetic effect? X
c Create light orglare? X
14.CULTURAL RESOURCES. Would the proposal:
a) Disturb paleontological resources? X
b) Disturb archaeological resources? X
c) Affect historical resources? X
d) Have the potential to cause.a physical change which would X
affect unique ethnic cultural values?
e) Restrict existing religious or sacred uses within the X
tential.im act area?:.:
I&RECREATION. *oLddthe; "roo oral:
a) increase the:demand fot,.r eigF b'th'dor regiorial parks X
orother' recreational:fadillties?'
b Affect existing.recreational o ortUhities? X
16..MANDATORY*aNDI.NGSib_
F_S.1G.N:.IFICAN.CE.
a) Does the project have the potential t6 "f Ode the_quality
of the environment substantially retl cede`habitat of a
fish or wildlife species cause pa j...hforviildl'ife.population to
drop below self-sustainigigv,'elk.tnreaten:to eliminate a X .
plant or animal commanity�;:risdj**tFie:ri rnbero(i- ct .
the range of a rare,or endarigeredlplaraf or animal;or
eliminate important:6.*Apfe 1f;t tieliiiajorperiods of
Califomia.histo or`iehisf0ji..
b) Ooes the protect Have the potenflal tg achlev..e short=;term,
to the;d sodvarita a riff 4QW— a ii-J PP nfial:goals? X
9 9 :- -
The proposed amendment is consistent with the long-term goal of keeping water demand within safe
yield.
c) Does the project haveimpagtstiiat:are; dyiduallyaimited,
but cumulatively considerable? V'Qi uiatively
considerable" means ithat;the incremental effects-of a X
project are considerable whert, ewed'in':.connection with
the effects of past projects;.tie;effects 6f nother current
projects, and the effects of: robable•future. ro ects
d) Does the project have environmental effects which will
Muse substantial adverse effects on human beings, either X
directly or indirectly?
9 5-27
17. EARLIER ANALYSES
Earlier analysis may be used where, pursuant to the tiering, program EIR, or other CEQA process, one or more
effects have been adequately analyzed in an earlier EIR or Negative Declaration. Section 15063 (c) (3) (D). In
this case a discussion should identify the following items:
a Earlier analysis used. Identify earlier analyses and state where they are available for review.
b) Impacts adequately addressed. Identify which effects from the above checklist were within the scope of and
adequately analyzed in an earlier document pursuant to applicable legal standards, and state whether such
effects were addressed by mitigation measures based on the earlier.analysis.
c) Mitigation measures. For effects that are "Less than Significant with Mitigation Incorporated," describe the
mitigation measures which were incorporated or refined from the earlier document and the extent to which
they address site-specific conditions:of the project
Authority: Public.Resources:Code SdiAon"s:2:1083 and 21087.
Reference:Public Resources Code Sections 2.1080(c), 21080.1, 21080.3,21082.1, 21083,21083.3,21093,
321094, 21151, Sundstrom v. County of Mendocino, 202 Cal. App. 3d 296 (1988); Leonofff v. Monterey Board.of
Supervisors, 2.22 Cal.App. 3d 1387.(l 990 .
18. SOURCE REFERENCES
1. 1 Genera!Plan Water& Wastewater Management, City of San Luis Obispo.
19. MITIGATION MEASURES &MITIGATION MONITORING
No mitigation measures are proposed as part of this environmental study.
siltation accounting ies.doc
5-28
DRAFT
SAN LUIS OBISPO
PLANNING COMMISSION MINUTES
APRIL 12, 2000
CALL TO ORDER/PLEDGE OF ALLEGIANCE:
The San Luis Obispo Planning Commission was called to order at 7:04 p.m. on
Wednesday, April 12, 2000, in Council Chamber of City Hall, 990 Palm Street, San Luis
Obispo, California.
ROLL CALL:
Present: Commissioners Allan Cooper, Jim Aiken, Mary Whittlesey, Alice Loh,
Orval Osborne, Stephen Peterson, and Chairman Paul Ready
Absent: None
Staff Recording Secretary Leaha Magee, Long Range Planning Manager John
Mandeville, Water Division Manager Gary Henderson, Utilities Director
John Moss, and Assistant City Attorney Gilbert Trujillo.
The Commission and staff welcomed newly appointed Commissioners Aiken and
Osborne.
ACCEPTANCE OF THE AGENDA:
The agenda was accepted as presented.
ACCEPTANCE OF THE MINUTES:
The Minutes of February 9 and March 8, 2000, were accepted as amended.
PUBLIC COMMENT ON NON-AGENDA ITEMS:
There were no non-agenda comments made.
PUBLIC HEARINGS:
1. Citywide: GPA and ER 41-00; Water Management Element amendment to clarify
siltation effects on capacity; City of San Luis Obispo, applicant.
Manager Henderson presented the staff report and recommended that the Planning
Commission recommend that the City Council approve a negative declaration of
environmental impact and amend the Water and Wastewater Management Element of
the General Plan to annually account for reductions in safe annual yield due to siltation.
5-29
Draft Planning Commission Minutes
April 12, 2000
Page 2
Commissioner Cooper had staff review storage capacity estimates for Whale Rock and
Salinas Reservoirs and noted the staff report should indicate the capacities listed are
estimates. Page 3, paragraph 2, should be clarified to note if the Salinas Reservoir
expansion project is included.
Manager Henderson noted that during the water rights process, an individual noticed
data input errors. However, there was no cause and effect relationship of this error.
Commissioner Cooper cited page 2, Attachments A and B, and asked if the Salinas
Reservoir expansion scheduled for 2112 would raise the river water level.
Manager Henderson stated downstream flows will be reduced during flood flow periods,
but analysis shows there will be no biological impacts downstream.
Commissioner Cooper stated Attachment C indicates a sloping stair-stepped increase in
water allocation, but a linear indication of population growth. He asked if annexations
would result in a stair-stepped population.
Manager Henderson responded that population estimates are based upon a one
percent growth rate, which is not to be exceeded per our General Plan. Water demand
increase estimates are based upon population increase.
Commissioner Whittlesey questioned the impact of the new numbers on the new water
supply requirements.
Manager Henderson stated the 55-acre feet would reduce the amount of water coming
in.
Commissioner Whittlesey asked if Section 6, page 15, of the existing Water Element,
would need to be amended.
Manger Henderson replied yes, staff will be bringing the entire Urban Water
Management Plan to the Planning Commission and City Council later this year for a
complete update, noting that it must be reviewed/updated every five years.
Commissioner Peterson noted staffs recommendation and Alternative 1 indicates the
safe annual yield line is safely above the water demand level until almost the same
juncture.
Commissioner Loh had staff review watershed per acre calculations for both Whale
Rock Reservoir and Salinas Reservoir. She asked if the recommended "no impact" for
the negative declaration still stands.
Manager Mandeville replied yes. No comments were received during the 21-day review
period.
Chairman Ready asked if it would economically feasible to remedy aspects of siltation.
5-30
Draft Planning Commission Minutes
April 12, 2000
Page 3
Manager Henderson stated this question is frequently raised, but the problem is
disposal of the silt that must be dug out. It is not economically feasible.
There were no further comments/questions and the public comment session was
opened.
PUBLIC COMMENT:
There were no public comments made.
COMMISSION COMMENTS:
Commissioner Loh moved to recommend that the City Council approve the negative
declaration of environmental impact and amend the Water and Wastewater
Management Element of the General Plan to annuallv account for reductions in safe
annual yield due to siltation, as corrected by staff to reflect an additional 55 acre feet per
year of safe annual yield beyond the previous figure of 7,735 acre feet per year which
includes groundwater. Commissioner Whittlesey seconded the motion.
Commissioner Peterson felt he could not support the motion. He said he prefers
Alternative 1 because it is a more conservative approach. He felt that in the past, the
City has run into trouble with not being conservative enough in water planning.
Commissioner Whittlesey commented that new development must complete retrofitting.
She was comfortable with the motion because the City is keeping pace with water
compared to development.
Commissioner Aiken noted that new development is required to more than offset water
they will be using.
Commissioner Cooper felt the staff report should better explain the water reuse program
and Salinas Reservoir enhancements.
Commissioner Osborne commented that without the assumption of the Salinas
Reservoir expansion, there would only be a one-year difference in comparison to staffs
recommendation versus Alternative 1.
AYES: Commrs. Loh, Whittlesey, Cooper, Aiken, Osborne, and Ready
NOES: Commr. Peterson
REFRAIN: None
The motion carried 6-1-0.
2. COMMENTS AND DISCUSSION:
A. Staff
Agenda Forecast:
5-31
Draft Planning Commission Minutes
April 12, 2000
Page 4
April 26 —The San Luis Marketplace EIR and Commission officer elections.
May 10—Wespac Investments annexation/business park request, Vineyard Church
Annexation and rezoning request, and two adjoining subdivision requests on
the east side of Broad Street.
Manager Mandeville reported the Draft Airport Area Specific Plan is expected to be
available for review in early May.
B. Commission
Chairman Ready will be absent April 26 and Commissioner Whittlesey will have to
refrain from participation due to a potential conflict of interest.
Commissioner Whittlesey will be absent May 10.
The Commission reached unanimous consensus to have Commissioner Whittlesey
serve as temporary vice-chair during Chairman Ready's April 26, 2000 absence. The
Commission agreed to reschedule its officer elections to May 24, 2000.
Commissioner Peterson requested staff reports include contact phone numbers and e-
mail addresses of their authors; this will make it easier for commissioners to get their
questions answered prior to meetings dates. The Commission supported this request.
ADJOURNMENT:
With no further business before the Commission, the meeting adjourned at 8:04 p.m. to
the next regular meeting scheduled for April 26, 2000, at 7:00 p.m. in Council
Chambers.
Respectfully submitted,
Leaha K. Magee
Recording Secretary
5-32