HomeMy WebLinkAbout04/05/1988, 4 - GROUND WATER STUDY �II�I���II�I�II�III=IIIIIIII "J MEETING DATE:
V_uu C,� (�01" san tins oBispo April 5, 198
mumm COUNCIL AGENDA REPORT ITEM NUMBER:
FROM: David F. Romero, Director Prepared By: William T. Hetland
Public Works Department Utilities Manager
SUBJECT:
Ground Water Study
CAO RECOMMENDATION:
Review results of Phases 1 & 2 of the Groundwater Study and
authorize by resolution to proceed with Phase 3 of the study
BACKGROUND:
The City's Draft Water Management Plan identified groundwater as a
potential water resource for the City of San Luis Obispo. The City
had previously used groundwater prior to the construction of
Salinas and Whale Rock Dams. On December 7, 1987, the Council
authorized the first two phases of the groundwater study. The firm
of John L. Wallace and Associates in conjunction with Timothy S.
Cleath, Engineering Geologist performed the investigation.
The objective of Phases 1 & 2, as identified in the scope of work,
was to quantify and describe baseline groundwater conditions within
the San Luis Obispo area and to describe constraints to the City's
development and domestic use of groundwater. This work was to be
performed using existing information.
SUMMARY OF GROUNDWATER STUDY
The study area for the groundwater investigation lies within the
City's urban reserve line. Data from existing information was
reviewed and analyzed to select those areas with the greatest
potential for groundwater development based on quantity of water,
water quality, and other developmental constraints.
Three areas appear to have the greatest potential for development.
Specific sites were selected within these three areas that were
examined in detail for their suitability as City well sites. The
seven sites found to be feasible from a geologic, hydraulic, water
quality and practical standpoint are:
UPPER SAN LUIS OBISPO CREEK:
Old Reservoir #1 - Highway 101 at Fox Hollow Road
Motel Inn - north Monterey Street
STENNER CREEK:
Anholm Site - 870 Mission Street
Community Garden - 533 Broad Street
Ferrini Site - Highway 1 at Stenner Creek Road
SOUTH CENTRAL SAN LUIS OBISPO:
Corporation Yard - Highway 101 at Prado Road
Dalidio Site - south of Madonna Plaza
�ii�►�►ll�l�I�p��l ��� city Of San LUSS OSISOO
MaGs COUNCIL AGENDA REPORT
Groundwater
Page Two
Blending of the groundwater from any of these sources with the
City's existing surface water sources would meet the California
State Department of Health Services' guidelines for municipal use.
Phase 3 of this study is to perform exploration at each of these
sites to confirm the potential for supplemental groundwater
supplies from these areas for the City. Subsequent phases,
Phases 4 & 5 for production well design and environmental
assessment would be completed after the results of the exploration
phase are known and decisions are made on the production required.
The executive summary on page i of the report highlights the key
points.
AUTHORIZATION OF ADDITIONAL WORK
The original contract scope of work was divided -into five phases.
The first two phases, which were the basis of this report, included
the survey of resources and the constraints analysis. Phase 3 is -
program design analysis with the emphasis on test drilling and
reviewing water treatment options. A groundwater development plan
which recommends specific well sites, conceptual system design,
and different groundwater use alternatives is done in Phase 4 . The
environmental impact review to assure the groundwater development
plan will be in compliance with CEQA is handled in Phase 5.
The consultant has identified a detail drilling program for
Phase 3. The program includes test borings, test wells, pumping
tests, and water quality tests. It is proposed Council authorize
the Phase 3 work. Recommendations on final scope of Phases 4 & 5
will be made at the completion of the test drilling. Phase 3 work
will take approximately 10 weeks to complete after Council
authorization.
FINANCIAL
The City's Capital Improvement Plan outlines a groundwater
development program as follows:
A. Study $ 501000
B. Design $ 101000
C. Construction $190, 000
The first two phases of the study portion just completed cost
$6,840. Phase 3 test drilling is estimated at $32, 110. The work
is still within the estimated $50, 000 budget for the study
portion. The funds are budgeted and simply require Council
authorization to proceed.
RECOMMENDATION
-Staff recommends that the Council authorize the consultant to �Z
proceed with Phase 3 of the study for an amount not to exceed
$32, 110.
RESOLUTION NO.. • (1988 SERIES)
A RESOLUTION OF THE COUNCIL OF THE CITY
OF SAN LUIS OBISPO AUTHORIZING JOHN L. WALLACE
AND ASSOCIATES'TO PROCEED WITH PHASE 3
OF THE GROUNDWATER STUDY
WHEREAS, the City of San Luis Obispo is interested in
investigating groundwater resources within the City; and
WHEREAS, the consultant, John L. Wallace and Associates, has
completed Phases 1 and 2 of the groundwater study; and
WHEREAS, the City of San Luis Obispo is interested in
performing test drilling to verify the results of Phases 1 and 2 .
NOW THEREFORE BE IT RESOLVED, Council authorizes the
consultant, John L. Wallace and Associates, to proceed with Phase 3
with scope of work for the groundwater study in an amount not to
exceed $32 , 110.
On the motion of seconded by
and on the following roll call vote:
AYES:
NOES:
ABSENT:
the foregoing resolution was passed and adopted this day of
1988.
MAYOR RON DUNIN
ATTEST:
CITY CLERK PAMELA VOGES
4-3
EXECUTIVE SUMMARY
In an effort to close the gap between increasing water demand and
the dependable supply of current sources, the City contracted
with John L . Wallace & Associates , in conjunction with Mr .
Timothy S . Cleath, to conduct this Ground Water Study which
defines the availability of ground water as a supplemental water
supply source for the City.
The purpose of this initial study is to identify ground water
resources available for possible development by the City of San
Luis Obispo. Specific sites are identified in this report where
wells may be developed and recommendations are made for testing
at three of these sites.
At the same time, a "safe yield" study of the San Luis Obispo
Creek and Pismo Creek ground water basins is being performed as
part of a three year study by the California State Department of
Water Resources (DWR) which takes into account a broader picture
of the ground water resources in the San Luis Obispo area. This
study does not duplicate the work being performed by the DWR,
i . e. it does not focus on the total ground water basin safe
yield. Instead, specific areas within the City's urban area were
assessed to determine one or more well sites that could produce a
dependable supplemental supply for the City.
Three areas within the City's Urban Reserve Line appear to hold
the greatest ground water development potential:
1 . The Upper San Luis Obispo Creek area
(560 acre-feet per year)
2 . The Stenner Creek area
(300 acre-feet per year)
3 . The South Central San Luis Obispo area
( 1000 acre-Peet per year)
The estimated yields shown in parenthesis are based on historical
groundwater usage . It is important to note that the overall
groundwater basin's safe yield will be defined as part of the
State's groundwater basin study. Also, production of the full
amount of water shown from the selected sites will depend upon
siting constraints and other considerations to be more fully
explored during Phases 3, 4, and 5 .
Additional ground water resources may be available by using
ground water extraction management techniques to maximize
recharge to the basin from surface water sources. San Luis
Obispo Creek is one waterway where such management techniques are
possible . These techniques include increased ground water
i 4-�-
production during high stream flow, resulting in some additional
percolation of surface water and subsequent recharging of the
alluvium being dewatered by the ground water production.
Specific sites were selected within these three areas that were
examined in detail for their suitability as City well sites . The
seven sites found to be feasible from a geologic, hydraulic,
water quality and practical. standpoint are:
UPPER SAN LUIS OBISPO CREEK:
Old Reservoir #1 - Highway 101 at Fox Hollow Road
Motel Inn - north Monterey Street
STENNER CREEK:
Anholm Site - 870 Mission Street
Community Garden - 533 Broad Street
Ferrini Site - Highway 1 at Stenner Creek Road
SOUTH CENTRAL SAN LUIS OBISPO:
Corporation Yard - Highway 101 at Prado Road
Dalidic Site - south of Madonna Plaza
Blending of the ground water from any of these sources with the
City's existing surface water sources would meet the California
State Department of Health Services ' guidelines for municipal
use.
In conclusion , we recommend that the City proceed with
exploration at each of these sites (Phase 3 of this study) to
confirm the potential for supplemental ground water supplies from
these areas for the City. Subsequent phases, phases 4 and 5 for
production well design and environmental assessment would be
completed after the results of the exploration phase are known
and decisions are made on the production required.
ii
CITY OF SAN LUIS OBISPO
1
G R O U N D W A T E R S T U D Y
1
1 SURVEY OF RESOURCES
AND.
CONSTRAINTS ANALYSIS
1
.} '.. ••• • .► •► ••
) \r//� . • •••e•• •• ••• ••• •••
i••��•� '• •• a ••
•► , ••, ••
a
. . . . . �
Y
i
�+ •• •• ••• u •►•••
1
•ha.y.Ytli. :: {L�:%::'::�:•'.': '.•••:•'
\\ V •: r•'I t • r • •a• • • •• •
i •'
{{�.. • :li•ay{ •u •u • u r ••• ••.••
•.\•• a •% •,t♦ .•• a •• • ••• ••• ►••
• • .\
fis
• ••V.••L"i •••�•••�• •i••�i•i�••i i
••:
• • \r.• ••. ••• •• ••,.., ••
• fir' u
Y
• u
u
••••�i ••�\. ,u • .. .• r•• .••
n41 . .•T• !.. t • ' 4• .r•
t
.{ l��•••••�•:\•: .•••.• •.••. .•••i
r
•• .• ••
•
i '♦Y J{}
R ,h1J
••
•••••• . r'•
•.•• ••u•.•
. ••••.
.•i•
•
i PREPARED BY:
i JOHN L. WALLACE 8 ASSOC. 1458 HIGUERA SAN LUIS OBISPO, CA. 93401
WITH TIMOTHY S. CLEATH, ENGINEERING GEOLOGIST
i MARCH 1988
' JOHN L. WALLACE & ASSOCIATES
CONSULTING CIVIL ENGINEERS
1
March 24, 1988
' City of San Luis Obispo
P .O. Box 8100
San Luis Obispo, CA 93403-8100
Attn: Mr. Hal Fones, Utilities Engineer
Subject: San Luis Obispo Ground Water Study -
Final Report; Phases 1 and 2
' Dear Mr. Fones:
Accompanying this letter is the final Ground Water Study report
' for Phases 1 and 2 which includes the comments made by you and
other City staff members during our meeting last week. We are
returning herewith your marked-up draft copies to facilitate your
' review of the final report .
It is our understanding that this report will be considered by
' the City Council on April 5 and we look forward to presenting our
findings at that meeting. In the mean time, please feel free to
call if you or other City staff have any questions or comments
about the project . We would like to personally thank you for your
time spent with us on this project and believe the report
reflects the extra effort taken.
Very my yours,
Jo n L. Wallace Timothy S. Cleath
Principal Engineering Geologist
1
' CMF •
JLWA J#61-2
' 1458 HIGUERA STREET•SAN LUIS OBISPO, CALIFORNIA 93401 •(805) 544-4011
r
r
tCITY OF SAN LUIS OBISPO
GROUND WATER STUDY
1
SURVEY OF RESOURCES
' AND
CONSTRAINTS ANALYSIS
1
' Prepared by:
' John L. Wallace & Associates
Consulting Civil Engineers
1458 Higuera Street
San Luis Obispo, CA 93401
(805) 544-4011
' In Conjunction With:
' Timothy S. Cleath
Engineering Geologist
r
March 1988
tCITY OF SAN LUIS OBISPO
GROUND WATER STUDY
SURVEY OF RESOURCES AND CONSTRAINTS ANALYSIS
1 '
Table of Contents
Section Page
EXECUTIVE SUMMARY i.
1 . INTRODUCTION 1
HISTORIC GROUND WATER USE . 1
2 . GROUND WATER SOURCES BY AREA . . . 4
UPPER SAN LUIS OBISPO CREEK 7
STENNER CREEK . 9
CENTRAL SAN LUIS OBISPO 11
LAGUNA LAKE 12
AIRPORT AREA .. 13
SOUTH CENTRAL SAN LUIS OBISPO 15
' 3 . GROUND WATER POTENTIAL . 17
GROUND WATER EXPLORATION 18
rWELL SITING CONSTRAINTS ANALYSIS 20
UPPER SAN LUIS OBI.SPO CREEK 21
Old Reservoir #1 Site 21
Motel Inn 23
STENNER CREEK 24
Anholm Site . 24
Community Garden 25
Ferrini Site 25
SOUTH CENTRAL SAN LUIS OBISPO . 27
Corporation Yard 27
Dalidio Site 28
1
Figure Page
1 Well Location Map . .. 3
2 San Luis Obispo Creek Flows 5
' 3 Proposed Well Sites 19
4 Legend to Site Maps 29
5 Old Reservoir No. 1 30
6 Motel Inn 31
7 Anholm Site . 32
8 Community Garden 33
9 Ferrini Site 34
10 Corporation Yard 35
11 Dalidio Site 36
Table
I1 Water Quality Data 8
2 Constraints Analysis Summary Table 22
LIST OF ABBREVIATIONS
cfs cubic feet per second
dia diameter
tgpm gallons per minute
MCL maximum contaminant level
mg/l milligrams per litre
TDS total dissolved solids
1
r
EXECUTIVE SUMMARY
In an effort to close the gap between increasing water demand and
the dependable supply of current sources, the City contracted
with John L . Wallace_ & Associates , in conjunction with Mr .
Timothy S . Cleath, to conduct this Ground Water Study which
defines the availability of ground water as a supplemental water
supply source for the City.
The purpose of this initial study is to identify ground water
resources available for possible development by the City of San
t Luis Obispo. Specific sites are identified in this report where
wells may be developed and recommendations are made for testing
at three of these sites .
At the same time, a "safe yield" study of the San Luis Obispo
Creek and Pismo Creek ground water basins is being performed as
part of a three year study by the California State Department of
' Water Resources (DWR) which takes into account a broader picture
of the ground water resources in the San Luis Obispo area. This
study does not duplicate the work being performed by the DWR,
i . e . it does not focus on the total ground water basin safe
yield. Instead, specific areas within the City's urban area were
assessed to determine one or more well sites that could produce a
dependable supplemental supply for the City.
' Three areas within the City's Urban Reserve Line appear to hold
the greatest ground water development potential :
1 . The Upper San Luis Obispo Creek area
(560 acre-feet per year)
2 . The Stenner Creek area
( 300 acre-feet per year)
3 . The South Central San Luis Obispo area
( 1000 acre-feet per year)
The estimated yields shown in parenthesis are based on historical
groundwater usage . It is important to note that the overall
groundwater basin's safe yield will be defined as part of the
State's groundwater basin study. Also, production of the full
amount of water shown from the selected sites will depend upon
siting constraints and other considerations to be more fully
explored during Phases 3 , 4, and 5 .
rAdditional ground water resources may be available by using
ground water extraction management techniques to maximize
recharge to the basin from surface water sources . San Luis
Obispo Creek is one waterway where such management techniques are
possible . These techniques include increased ground water
r i
1
production during high stream flow, resulting in some additional
percolation of surface water and subsequent recharging of the
' alluvium being dewatered by the ground water production.
Specific sites were selected within these three areas that were
examined in detail for their suitability as City well sites . The
seven sites found to be feasible from a geologic, hydraulic ,
water quality and practical standpoint are :
' UPPER SAN LUIS OBISPO CREEK:
Old Reservoir #1 - Highway 101 at Fox Hollow Road
' Motel Inn - north Monterey Street
STENNER CREEK:
Anholm Site - 870 Mission Street
Community Garden - 533 Broad Street
Ferrini Site - Highway 1 at Stenner Creek Road
SOUTH CENTRAL SAN LUIS OBISPO :
' Corporation Yard - Highway 101 at Prado Road
Dalidio Site - south of Madonna Plaza
' Blending of the ground water from any of these sources with the
City' s existing surface water sources would meet the California
State Department of Health Services ' guidelines for municipal
use.
In conclusion , we recommend that the City proceed with
exploration at each of these sites (Phase 3 of this study) to
confirm the potential for supplemental ground water supplies from
these areas for the City. Subsequent phases, phases 4 and 5 for
production well design and environmental assessment would be
completed after the results of the exploration phase are known
and decisions are made on the production required.
1
i
1 . INTRODUCTION
' This report presents a survey of ground water resources and
constraints related to locations which should be explored as
potential well sites . The information upon which the findings
have been based is a compilation of historic records, verbal
communication , reports on local water resources , and a
reconnaissance of the area performed specifically for this
report . The references and individuals contacted during this
study are presented in the appendixes.
The study area lies within the urban reserve line of the City of
San Luis Obispo. This area, shown on Figure 1 , covers an area of
approximately 11 . 5 square miles. The object of this study is to
' evaluate potential ground water resources within the alluvial
ground water basin underlying the City of San Luis Obispo. The
area of investigation was further limited by excluding areas
where alluvium is absent. The geologic formations underlying the
alluvium are much more consolidated and do not store or yield
water as readily as does the more porous and permeable alluvium.
' The study area can be divided into several areas based upon the
streams traversing the study area. Stenner Creek drains the
northern portion of the study area (Stenner Creek area) . The
upper San Luis Obispo Creek drains the northeastern portion of
the study area (Upper San Luis Obispo Creek area) . The central
portion of the study area is downstream of the confluence of
' these two creeks and above the Madonna Road/Highway 101
intersection (Central San Luis Obispo area) . The southwestern
area is west of Madonna Road in the Los Osos Valley (Laguna Lake
' area) . The southeastern area is drained by the East Fork of San
Luis Obispo Creek (Airport Area) . The south-central area is the
area generally between Madonna Road, Higuera Street, and the
Irish Hills which receives inflow from all of the aforementioned
' areas ( South Central San Luis Obispo area) . These areas are
defined in Figure .1 .
' HISTORIC GROUND, WATER USE
CITY OF SAN LUIS OBISPO
The ground water sources which have been used historically by the
City of San Luis Obispo are saturated alluvial deposits
associated with San Luis Obispo Creek, Stenner Creek, and San
Luis Valley. Very few wells remain which were previously used by
the City and none would .be permitted for use by the California
Department of Health Services. Therefore, future ground water
supply facilities would be new wells rather than those used in
the past.
1
' The City of San Luis Obispo used local ground water from at least
nine wells and surface water sources for municipal purposes prior
' to conversion to the Salinas Reservoir in 1942 and use of the
Whale Rock Reservoir in the 1960 's . The two early surface water
diversions were on San Luis Obispo Creek and the tributary
Reservoir .Canyon system. The surface water agreement with
property owners on San Luis Obispo Creek has been maintained by
the City, as the City continues to make available surface water
from the diversion pipeline to these property owners for domestic
' use. The Reservoir Canyon water diversion, on the other hand, is
largely in disuse.
' The City owned or purchased water from several wells in the
vicinity of the City, which included Reservoir No. 1 well , the
Buchon Street wells (near Johnson Avenue) , the Garden Street well
(Pismo well ) , the Meinecke well (near Santa Rosa and Meinecke
' Streets) , the Anholm well (near Mission and Chorro Streets) , the
DeVaul wells, and a few wells on the Dalidio property. Only the
Anholm well and Dalidio wells nos. 1 , 3, and 4 remain from this
group of wells . The Anholm well , however, is inactive. The
Dalidio wells nos. l and 3 are currently used for irrigation.
The City has also used a well along the San Luis Obispo Creek
adjacent to the treatment plant for irrigation ( the "Gudel" well)
and is currently using a low yield, shallow well at the treatment
plant for non-potable uses. The location of these wells are
shown on Figure 1 .
' Annual ground water production records for these wells apparently
do not exist, therefore much of the information compiled for this
' report has been obtained from less formal sources .
r
r
i
r 2
i
'.� 1 <. C �/,ice '.<'� \ ��1\•-�����K.�,�� ,
,
,
. �
' ���7
✓\ `� ��\ .� till .�, � •'�1` .., �� � 7� j �_
• -� •'/ ' . '� ,-� Ll.�ll,�; /�is
• E '• — \v/
\ I w
a � F�� '' I\ �a `/; J�""ice �,_'\\ ° - l' ��,•
' ,� a e C • ^'i I � r 0` •• , � Fes-\J�� � �S. �, ��1�- � `�^
J �l
' C. �1 L ,� ��I/�,�r,�t(,( j- SIJ I��� T Ix�•Ifl� > /I �-r
. � ' ' — -�A• '.'"- -� � ',,.. ill Jul \y ��If •� � �'� � '�� %�� �; N' ,>s
r-j .Old/ � '/,�� � •.' •• • �•... • •������\:. _.I , • _.__ i - =.
'�.)� �/' IIS. /b,'-C ,� ('.. •'>G °f � � � �� i�)I� � ,'��� �-��-� .^�.mll� r~fir
wy. „�.I«�� - .�• r � ��.f ( o,I / R �1 tom. Il�
WIN
IL
y
m
x
V a z
• OO > o'
z
m > c >
-4 'o
a �jmr c m O
s yr = < = z
m
> o = a c = e
i < CA Z m m
m
m "or' ac
o =1 z 1°
Am -1 y
0
> >
z �
cZ
N �
O >
y
O
' 2. GROUND WATER SOURCE AREAS
The ground water basin within the City's Urban Reserve Line can
be divided into six areas . Each of these is distinguished with
respect to aquifer characteristics , ground water level
fluctuations , ground water recharge, ground water usage, well
yields , water quality and water rights issues. Each area is
herein evaluated with respect to these elements.
Some general comments on the San Luis Obispo ground water basin
are initially appropriate. The study area includes most of the
ground water basin. The remaining portion of the ground water
basin is primarily west of the study area in the Los Osos Valley
and is typically shallow. The alluvial basin is predominantly
fine grained material in this area and alluvial wells have low
yields and are used for domestic purposes .
' The ground water basin is overlain by San Luis Obispo Creek and
its tributaries: Stenner Creek, the East Fork of San Luis Obispo
Creek, and Prefumo Creek. San Luis Obispo Creek is the only
gaged stream which has flow records. The creek has two stations:
one on upper San Luis Obispo Creek and one downstream at San Luis
Bay Drive. Figure 2 illustrates flow records at these stations .
' The disposal of treated wastewater effluent from the City of San
Luis Obispo augments flow in San Luis Obispo Creek near the Los
Osos Valley Road bridge.
There are a few reservoirs which are used to store water for
agricultural irrigation and flood control purposes, but these are
not of significant storage capacity and are outside of the study
area. Laguna Lake, the only naturally formed lake in the study
area, receives winter runoff and discharges water to Prefumo
Creek. Laguna Lake covers an area of 193 acres and has the
capacity to store 933 acre-feet of water when filled to the
overflow at Madonna Road. Lake storage capacity has decreased to
about one half of what was estimated in 1910 .
' The San Luis Obispo ground water basin is comprised of alluvial
deposits laid down by San Luis Obispo Creek and its tributaries .
These deposits include sand, gravel , silt and clay layers . Sand
and gravel layers within the alluvium yield the most water to
wells while interlayered clays or clay and gravel beds have much
lower permeabilities.
4
I• r �r r r r r� .r �r r r r . r rr a■� r r �r
STREAMFLOW, cfs
e o 0 0 'o 0 0
ca
- -
I I I I I
'• -- _ I 1 1
� I I
Im
_==__ - 1--- -+-_- II III III
= I. -- -._ �=TI—_'" _ STREAIAPI.Ow, aft
Go
m --
� � 1 I
L
O . ! ii
-.: Tili ' ii 11 it III
� I1
-+--�— I : r
m j
__ I I I IT �� I
'
_ I I i _► 1
O V I 1 it I I I I i I laI , IIIIIII I I I I I
Cb
CA
i i w—_= , ' I I I I-• j 1 1 I I I j-I I_: 1 ! I I I I I I � 1 11 1 I
I
O ml — -- I I I i II I IIII I I i- I -II II I I S ' II ' illl ' I I '
= Lj
_ IT ----_-- ' — II hH III
m I
—71 _= T - -
�.T
L- II
OiDA�_j_ — I i ; II I II II _ aq }A ( O
� I 7 I II
_ II
Ili i t I 1 i �
-
- I I I
I I I I 1 I ,
I I I I
l
_--- f I i 1 w
_ I I 1
— — — I-
Fi
O F .
1 -- _!.I I I I- II - I _ �- ' i I I I. I I ' I I. i I ► I O
CD o
— ^—
L I 1 I
clo
1 li iI Ii L. I_ Ili ' I IiI ' i I
N
I-
-.-=
_ ---
i
I --
a I
I i 1 I
1 --
I
I
I
>
a
z z
C > 3
z
a > „ 30
Z c
z r= r > 3
< O
c III" * < >
N r 'a In F
w �° °
MO �_rA �
G z M m
O ; = C r. m
IT
m z D m z K
x S N = Z
S
Along the narrow alluvial basins in the Stenner Creek, Upper San
Luis Obispo Creek, and Central San Luis Obispo areas , the maximum
thickness of the alluvium is generally less than eighty feet .
Actual lithologic data from well logs is limited to only three or
' _ four wells in each of these areas, however, so that a detailed
isopach map of alluvial thickness is not possible. In the Laguna
Lake and the Airport area, the alluvial deposits cover more area
and are generally less than 120 feet thick. The Airport area
' west of the tank farm has much thinner alluvial deposits ,
typically less than 60 feet . The South Central San Luis Obispo
area is the area where alluvium is thickest - being up to 170
' feet as encountered in some wells.
Underlying and adjacent to the alluvium, the geologic formations
' are much older igneous, metamorphic, and consolidated sediments.
While water can be encountered in these rock types , it is
commonly in lesser quantities and more difficult to develop.
There are some exceptions to this general observation, of course.
' Within the Franciscan Formation, the metavolcanics along the base
of the Irish Hills are fractured in part due to relatively recent
tectonic activity along the Los Osos Valley fault and yield water
' to wells. The depth of fractured rock is more than 300 feet .
In the extreme south and southeast corner of the study area, some
marine sandstone beds are present. Ground water production from
' wells producing from these beds is not great, but southeast of
the urban reserve line, in the vicinity of the Rolling Hills and
Country Club developments, more favorable water bearing sand beds
occur.
Aquifer characteristics such as specific yield (the percent of
' available water stored in the alluvium) and permeability, vary
widely with the type of sediment comprising the alluvium. Since .
sand and gravel zones are the most favorable types of sediments
( i . e . , high ground water storage potential and high
permeability) , the thickness of these beds is critical to the
production rate possible from a well . Equally critical is the
depth at which the sand and gravel beds occur, since the shallow
beds must be sealed off to avoid potential contamination and to
maintain a dependable yield by allowing for seasonal water level
fluctuations. The State Department of Health Services recommends
a sanitary seal of 50 feet but allows exceptions for shallow
wells.
These aquifer characteristics are described under the discussions
of each area.
6
UPPER SAN LUIS OBISPO CREEK AREA
' The Upper San Luis Obispo Creek area includes the alluvial
deposits adjacent to and underlying San Luis Obispo Creek
' upstream of Johnson Avenue to the old Reservoir No. 1 site. The
alluvium is about 1000 feet wide in the vicinity of the high
school and narrows to less than 300 feet width upstream of Cuesta
County Park. There are no logs available for wells in this area,
' but maximum well depths are from 50 to 55 feet.
Water levels in wells fluctuate widely depending upon the season
' and flow in San Luis Obispo Creek. During dry years, water
levels have .dropped from a depth of 18 . 66 feet to 35 feet in the
old Buchon Street wells. This low water level was noted during a
period when the City diversions on San Luis Obispo Creek and
' Reservoir Canyon were in use. The creek does dry up during dry
seasons , as in 1976-1977 when several months of no flow were
observed. According to the 1977 Water Supply Study prepared for
' the City by Engineering Science, the City's stream diversion on
San Luis Obispo Creek is known to have a base flow of about 200
acre-feet per year. The Reservoir Canyon diversion combined with
the San Luis Obispo Creek diversion is estimated to have reliable
yield of 500,000 gallons per day (560 acre-feet per year) based
on the 1922 Ryder study. This 1922 study provides valuable
information even by today's standards. In light of the lack of
use from these diversions., flow through to the creek in the Upper
San Luis Obispo Creek area should be similar to this combined
yield estimate.
Individual well yields have been greater than 150 gallons per
minute (gpm) in the deeper parts of the alluvial basin with some
t wells yielding 350 gpm. Water level fluctuations and direct
creek recharge to the ground water influence well yields
significantly.
1 Water quality for various wells and creek water samples are
included in Table 1 . The area receives inflow from undeveloped
areas and while contamination from spills into San Luis Obispo
' Creek are possible, ground water is not expected to have non-
native contaminants. Generally, total dissolved solids (TDS) in
surface water vary from 350 milligram per litre (mg/1 ) to 460
mg/l and hardness in surface and ground water is between 330 mg/l
and 392 mg/1 . No dissolved chemicals constituents are known to
exceed state maximum contaminant levels (MCL) .
' Pre-1914 water rights are claimed on Gularte. and Hansen Canyons
and Reservoir Canyon by the City of San Luis Obispo. Recent
Statements Nos . 618, 619, and 620 filed with the California Water
' Resources Control Board, Water Rights Division are records of
these diversions and are for 0. 135 cubic feet per second (cfs) ,
0. 135 cfs, and no defined quantity, respectively.
' 7
' -------• •--------------- -
Ooo1., � � m oo
1 A 1 b In ! • O O O 1
1 W 1 N N O b 01 1
1 J 1 O ^ 1
-------�.---------- 1
1 1 1
-------------
--
------- ----
1 1 Yn _C 1 1
1 1 1 1
1 I Y 1 1
1 W 1 C m F 1 N O O O N O b m 1
1 ^ W ^ 1 1
1 1 q = 1 1
1 ^ 1 3 1 ——————————————--
1 V I Y 1 I
• ! m ^ 1
O ^ N a F I
i i e w m i o i
1 1 L C 1 1
--———————————
1 1 1
1 1 !A O Of 1 b b 4 fC b b ^ G O O N 1
1 L N 1 O O O F 1
1 m 1 1
————————^—————————!
1 N 1 ! F ^ 1 1f1 N 11Y 1 A A 1 b O M O 1
O O 1
1 ^ OI 1 1
I
_________ 1
1 O 1 ! m O to 0 N O 1 ! ^ N 1 O M O b 1
1 m 1 t Q
t C O b 1 1
1 OI q 1 1
I J W 1 t
W
/ ID Y 1 F 01 01 1 b F F N If9 b l� N 0 0 ! 1
t W L 1 F ! O ^ b O ^ N 01 b m 1
/m
I m 1 O O 1
1 W q O) 1 1 O
1 7 N N 1 1
j J 1 1 cc
t C U 1 1
IR I W
1 F 1 iA ! t� Oi ^ OO Af N • A II"! 1
1 Q) 1 !A Y9 b Y9 O O1 1 N
1 q \ 1 Of F
00c;
O of F 1 N
'--�
1
-----Z'7
O---------------- W V
1 L 1 ! b 0 1 N b 1 b m O 1 O O 1 1 1 T •r 1�
CD
1 T 119 1 O O 1 V Il)
I W F 1 v 1 VI {n V
1 C r ^ 1 1 4 r T
1 O 1 1 ^ q L
1 r 1 J q
1 L
1 to
1 O 1 T
------------------
.10----------------- .10
1 ^p ! 1 N Q) m = F N F 1 C G L
i' Lpp CX 1 @ q
1 1 b F ! O lff b O N b b A A 1 V W E
I O b I ! O G O O F I T
1 T m I O O F IIY 1 H ^ W -0
I T I 1
--------.----------' � O
1 n n 1 6 6@ H m m m C • m W 2 Y O,L 1 T M coC
W
1 q
I O n 1 T T T g T q v 0 L m m H T 1 -02 Y L
1 T n 1 ^ W W L 1► Z �••• C L C > 1 C 01
0 - T I m W
1 q m 1 q C Yn q 7 Y O O L Y 1 L
g O C q V 1 L
1 i a i A iAi
————--——————————--————--——
1
1
1
STENNBR CREEK AREA
' The Stenner creek area, upstream of the confluence of Stenner
Creek with San Luis Obispo Creek, has alluvium with a width of
about 1000 to 1500 feet . The alluvium is known to be about 80
feet thick in the deepest alluvial well . Only one well (Cal Poly
Orchard Well) was found which had a log. The only gravel noted
was in gravel and clay streaks found from 58 to 76 feet but a
t blue shale from 10 to 58 feet could also be interpreted as
gravel .
' Ground water levels have fluctuated in the Meinecke well from 17
feet to 39. feet . Some of the area near Foothill Boulevard and
Santa Rosa Street was known for its marsh area . Reduced
discharge rates in these irrigation wells occur when ground water
tlevels are low.
Studies performed on Stenner Creek show that surface flow varies
with time of year and location. The flows were measured during
the summer of 1921 and were found to be minimal ( less than 0. 3
cubic feet per second) at best . The duration of no flow is not
' known due to lack of -data, but is thought to be several months
during dry years . Ground water production during those dry
seasons would diminish from winter levels. Another impact on
stream flow in Stenner Creek is the direct diversion off of
Stenner Creek to California Polytechnic State University for
irrigation purposes . This impact is minimized since the
diversion is used only four days of each week from May i through
' October 31 . This has been the operating procedure based on an
agreement between Cal Poly and the Ferrini family in 1959 . This
procedure results in recharge to the alluvial aquifer downstream
of the diversion.
1 Water production from the Stenner Creek area has historically
been used for agriculture and domestic purposes. The Cheda and
Fiscalini Ranches used stream diversions and wells respectively
for water supply , as did the Ferrini Ranch . The Cheda and
Fiscalini properties are now part of Cal Poly which continues to
' use the stream diversion and several wells. The Ferrini family
continues to use their well . The City of San Luis Obispo in the
period before 1942 used water from several wells for supply
(Meinecke, Steiner, and Anholm wells) . Although no estimates of
' ground water pumpage for the City are known, possibly as much as
a few hundred acre-feet was obtained from this area by the City.
Other local farms also had wells in use in this area.
The current pumpage is by and large used by Cal Poly with a
lesser amount used by Ferrini.. The water use by Cal Poly has
been for irrigation of pasture and dairy operations, crops , and
the orchard. The total agricultural use in 1955-1960 averaged
438 acre-feet per year.
i 9
1
1
' Recent figures are only for the dairy operation, 160 acre-feet
per year. Domestic water supply for Cal Poly before 1960 was
' obtained from ground water, totalling about 300 acre-feet per
year. Since Whale Rock reservoir was constructed, Cal Poly has
obtained its domestic and some irrigation water from that source
' and discontinued use of the two domestic wells for domestic water
supply purposes . The Ferrini well is used for stock watering,
currently.
' Some wells located in the Stenner Creek area include:
NAME OF WELL MAXIMUM PUKING RATE STATUS
' Cal Poly Domestic #1 160 gpm in use
Cal Poly Domestic #2 190 gpm idle
' Cal Poly Field 25 (Fiscalini) 905 gpm in use
Cal Poly Orchard 210 gpm in use
Ferrini 200 gpm in use
Anholm 115 gpm capped
' Meinecke 175 gpm abandoned
Steiner 250 gpm abandoned ?
' The usage of local water in this area does not appear to be as
great now as it has been in the past. Whereas in 1959, Cal Poly
and Ferrini used 863 acre-feet per year, current water usage is
probably less than one-half that now. Therefore, there is ground
' water available from this area. A potential yield of 300 acre-
feet from this area for additional uses appears to be a
reasonable figure based on the City's previous historic use and
' in light of current lower ground water usage.
Water quality analyses are available for the Ferrini well and the
' old wells used by the City. These are summarized in the water
quality table , Table 1 . The total dissolved solids at the
Ferrini well was 480 mg/1 and the total hardness of the water
from these wells ranged from 300 mg/l to 380 mg/1 . No available
water quality results exceed state MCL guidelines. The potential
for contamination is moderate in this area since gas station
spills have been noted , but no situation resulting in the
' contamination of active production wells is known to have
occurred. There are a few shallow wells in use along the creeks
for home garden irrigation. Some of these wells are reported to
produce water with iron. This is likely to be a natural
' condition.
Water rights along Stenner Creek have been dealt with through the
' courts and through private agreements . Surface water diversion
from Stenner Creek by Cal Poly is performed as a riparian right
under which Cal Poly has a right to use their proportional share
' of the natural flow in the creek for reasonable beneficial use
on riparian land.
' 10
1
tCal Poly has established a license for diversion and storage of
Brizziolari Creek flow under Application No. 13068 to the State
' which allows direct diversion of maximum flow of 0 . 06 cfs from
April 1 to October 1 for irrigation and for storage of 23 acre-
feet from October 1 to April 1 .
' Ground water rights are held by Cal Poly and Ferrini as overlying
landowners in which each is entitled to a reasonable share of the
ground water supply for reasonable beneficial use on overlying
' land. No formal appropriative rights on the ground water have
been filed. These water rights do not exclude downstream ground
water uses, however .
' CENTRAL SAN LUIS OBISPO AREA
The downtown commercial area overlies the Central San Luis Obispo
' area where shallow ground water is evident. Some basements of
buildings downtown have to deal with flooding at times from
ground water as well as flood flows of San Luis Obispo Creek.
' Historic use in the area includes the City's well at Garden
Street and Pismo Street , the Modern laundry well on Pacific,
' several domestic wells near Mitchell Park and the Dana Ice
Company well at High Street and Higuera Street . . Since only one
of these wells is in use now (the Dana Ice Company well ) , little
information is available on the alluvial deposits and ground
' water, and even less is current .
These wells produce from sand and gravel deposits in the
' alluvium. The thickness of the alluvium appears to be as much as
80 feet (as noted in the City's Garden Street well - currently
where the Fire Station is located on Pismo Street) . A report on
' this well indicates there is a clay zone in the upper alluvial
deposits with deeper gravel beds. The soil borings downstream at
the Madonna Road overpass identify a somewhat shallower depth (65
feet) , but similar stratification.
tThe ground water in this area receives recharge from San Luis
Obispo Creek and percolation of return flow from urban uses .
' This area currently has negligible ground water production,
although during the early 1900 ' s ground water production was
probably a couple hundred acre-feet per year. This production
appeared to be reliable even in the Summer months. Individual
' well ground water production is only known for the Garden
Street/Pismo Street well which had a discharge rate of 1300 gpm
with 3. 5 feet of drawdown. Depth to ground water level in that
' well fluctuated between 12 feet and 30 feet during wet and dry
seasons, respectively.
' Ground water quality appears to be somewhat poorer than in the
Upper San Luis Obispo Creek and Stenner Creek areas .
11
' Analyses for water in the old Garden Street well and Dana Ice
Company well found total dissolved solids of 650 mg/l and total
' hardness ranging from 520 mg/l to 655 mg/1 . Iron and manganese
concentrations were near to, but below limits established by the
State for drinking water. The development of this area has
resulted in some contamination of the water by petroleum
' products, also.
No water rights actions are known to be in force for ground water
' in this area.
LAGUNA LAKE AREA
' The Laguna Lake area is underlain by up to 120 feet of alluvium, ,
but only a couple of small production wells are in use at this
time . Laguna Lake, as previously discussed, is fed by runoff
during storms and probably does , in some way, interact with
adjacent and underlying ground water.
' The geology of this area is complicated by some relatively recent
tectonic activity along traces of the Los Osos Valley fault.
This is currently under investigation by consultants for PG & E
' as a part of seismic studies related to Diablo Canyon Nuclear
Power Plant. Some of the faulting has disrupted the alluvium and
created ground water barriers within the alluvium. The faulting
also has appeared to have created fracture permeability in the
' underlying bedrock. The results of this study, currently
pending , may aid in understanding and anticipating areas of
potential ground water production along the south western border
of this area.
The alluvium encountered in the City's test well at the municipal
golf course was predominantly clay strata extending to a depth of
about 100 feet. Near Madonna Road and Los Osos Valley Road there
is alluvium to a depth of 168 feet with a total of about 50 feet
thickness of gravel deposits.
' The City's well at the golf course had a depth to static water
level of 18 . 58 feet in September 1987 . This would be an
' elevation of about 125 feet. To the northwest of the study area,
there are several producing wells in the Franciscan Formation
underlying the alluvium. Some of these wells have significant .
water level declines over dry seasons which reduce ground water
' production from the wells.
The potential yield from this portion of the ground water basin
is difficult to judge based on existing information. Certainly,
the production of water from the test well at the golf course
would not have a significant impact on the area as a whole and it
should not have much affect, if any, on water stored in Laguna
Lake.
' 12
' Wells placed nearer the lake could, potentially, draw some water
from the lake since shallow gravels were encountered at the lake.
' This could be a significant impact if the extractions are high.
With roughly 2000 acre-feet of ground water in storage in this
area and inflow occurring in winter, the use of 200 acre-feet
' would result in an average water level decline of less than 10
feet and probably not influence lake water levels, if the well
were to be located away from the lake.
t Water quality in this area can only be judged by the lake water
and the test well at the golf course. The lake water quality
varies with the time of year due to inflow and bioaccumulation
' effects . These are described in the City's Management Plan for
Laguna Lake. A recent analysis performed on the lake water for
this study found a TDS concentration of 480 mg/l and a Total
Hardness of 330 mg/1 . Manganese concentration was high at 0. 114
' mg/l as was turbidity and color.
The ground water quality is variable with location, but the City
' test well at the golf course provides a good general indication
of what is present . The TDS concentration of 500 mg/l and
hardness of 376 mg/l were found with concentrations of iron and
manganese exceeding state guidelines . The manganese
concentration analyzed at 0.07 to 0. 11 mg/l appears to be the
mineral which exceeds the guidelines (0 .05 mg/1) by the greatest
percentage. One other analysis of a well west of the study area
' (Laguna Hills Estates well #4) found a total hardness of only 130
mg/l and TDS of '630 mg/1 .
There are no known appropriative rights to Laguna Lake or Prefumo
Canyon in this area.
AIRPORT AREA
A 1986 study performed for the County of San Luis Obispo
addressed the ground water conditions in the San Luis Obispo
t Airport Area. This report covers hydrogeologic aspects pertinent
to the full utilization of ground water in the Airport area . A
summary of its findings is presented in the following paragraphs .
The Airport area is underlain by alluvial deposits reaching a
thickness of 160 feet, but is more commonly less than 100 feet
thick. The thickest alluvium is located in the southwest corner
' of the area (near Higuera Street and Tank Farm Road) .
Ground water generally flows northeast to southwest with a
1 typical gradient of 0 . 005 feet per foot . Water level
fluctuations have been monitored in several alluvial wells in
this area for more than 20 years and had a historic range of 10
to 12 feet with typical annual fluctuations of less than 5 feet .
1 13
1
' The Airport area receives recharge from intermittent seasonal
flow on the East Fork of San Luis Obispo Creek. A recent study
' of this area estimates that 1150 acre-feet per year of recharge
typically occurs and that ground water in storage acts to buffer
year to year variations in recharge. Surface flow recharge to
ground water is about 350 acre-feet/year typically, but dry years
result in much lower ground water recharge . The cultural
development of this area has involved the drilling of many low
capacity wells and on-site wastewater disposal systems . The net
' consumption from this development is estimated to be 265 acre-
feet per year.
' Ground water quality is quite variable in this area, but is
typically poorer than in the other portions of the study area. A
survey of 40 property owners found that about half of the
respondents did not drink the water . The ground water on the
t east side of the Airport area has conductivity measurements
ranging from 1150 micromhos per centimeter to 2924 micromhos per
centimeter and on the west side it ranges from 980 to 1853
' micromhos per centimeter . These measurements can be roughly
compared to total dissolved solids by multiplying them by 0 .7 .
Therefore, there is a much higher mineral content in the ground
' water of this area, as a whole . Hardness is also typically
higher than the other parts of the study area with levels greater
than 500 mg/1 occurring over much of the area. The use of this
water has been found to be detrimental to use in truck radiators .
' There are some areas where nitrate concentrations exceed State
guidelines such as near Suburban Road and in the vicinity of Tank
t Farm Road and Santa Fe Road. This may be due in part to on-site
wastewater disposal system contributions to the ground water .
Near Margarita Lane, the nitrate levels in the ground water are
within acceptable limits.
1 There are no permits for appropriat.ive rights nor are there
Statements of Diversion and Use in this area.
' There is considerable potential for conflicting interests when
ground water resources in this area are considered to supplement
' the City's water supply. Several development scenarios for this
area are being contemplated which would result in full
utilization of ground water resources. In light of the existence
of many on-site water supply systems, the potential impact of
' large ground water production in this . area for the City's use
could be significant .
' With these potential impacts in mind and the significantly poorer
water quality in this area , the use of ground water in the
Airport area to augment the City water supply is not recommended.
1
' 14
1
1
1
SOUTH CENTRAL SAN LUIS OBISPO AREA
' This area includes the Dalidio expansion area and the Lower
Higuera area and is known to have some of the most favorable
' ground water conditions in the study area.
The alluvium in this area is up to 170 feet thick and includes
roughly 50 feet thickness of sand and gravel beds. Sand and
' gravel beds are interspersed through the full thickness of
alluvium. Aquifer definition is difficult due to the lack of
drilling data on wells in the area. Most wells are old and
' whatever records which may have existed are not available now.
Of about 30 wells known to be in the area, only about a half
dozen wells have logs on them and/or are in operating condition.
Significant aquifers are known to occur between 45 feet and 100
' feet and there are additional aquifers below 100 feet. One well
log records an 18-foot thick gravel bed at the base of the
alluvium.
' The South Central San Luis Obispo area holds the greatest
potential for reliable ground water production. Recharge from
' San Luis Obispo Creek, augmented at the downstream limit of this
area by the City ' s treated effluent disposal to the creek,
maintains water levels in this area. The operation of wells in
the area does not appear to have been affected when water level
' fluctuations of 20 feet occurred in the late 19301s . Ground
water production in this area currently is used for irrigation of
truck crops and landscape. With about 200 acres in irrigation,
' and a water consumption of 3-4 feet per year for the harvesting
of more than 2 crops per year, the total ground water use in this
portion of the basin would be 600-800 acre-feet per year. This
' figure for ground water usage by agriculture is probably about
the same as what was used in the late 1930 's when ground water
production for the City in this area was greatest . The City's
use of ground water from this area was on the order of several
' hundred acre-feet per year at its zenith. . We estimate with all
combined sources considered, that about 1500 acre-feet per year
was extracted from the ground water in the late 1930 ' s from this
' area.
Additional yield from the ground water basin in this area may be
available since the City' s treated wastewater effluent disposal
' to the creek is likely to enhance ground water recharge. The
only mention of a safe yield for this ground water basin (DWR
Bulletin 18) stipulates that "the safe yields could be increased
' by an amount no greater than the present effluent flow from these
basins . " Today' s effluent flow from the study area is much
greater than was identified during that study, performed between
' 1953 and 1956. Current wastewater effluent disposal to San Luis
Obispo Creek exceeds 4000 acre-feet per year as compared to about
2240 acre-feet in 1956.
' 15
1 Based on historic pumpage and current treated wastewater effluent
disposal , the quantity of ground water available from this area
' is, therefore, estimated to be 1000+ acre-feet per year . Should
the Dalidio property be taken out of agriculture and developed
according to existing City and County planning documents , about
' 100 acres of irrigated farmland would no longer be irrigated,
increasing the available ground water in this area by an
additional 300 acre-feet, for a total of 1300 acre-feet per year .
' Ground water quality parameter concentrations in this area vary
with total dissolved solids concentration ranging from 352 to 670
mg/l and total hardness ranging from 290 to 460 mg/1 . Analyses
' for the Dalidio wells show that quality varies with time as well
as location. A January 1986 analyses found a TDS of 670 rag/l in
Dalidio well #2. In an analysis in 1940 of the same well , TDS by
summation was 834 mg/l and the water was high in sodium and
chloride ions. These high sodium and chloride levels ( 260 mg/l
and 350 mg/l , respectively in the adjacent Dalidio well #3 )
cannot be explained due to lack of supporting information. The
' most recent analytic results ( January 14 , 1986 ) should be
considered as the more valid results.
' No formal water rights applications or judgments are known to
have been made for this portion of the study area.
1
1
1
1
1
1
' 16
1
1
3. GROUND WATER POTENTIAL
The six areas addressed in the previous section of this report
are 1 ) the Upper San Luis Obispo Creek area, 2 ) the Stenner Creek
area , 3) the Central San Luis Obispo area, 4) the Laguna Lake
area , 5 ) the Airport area, and 6) the South Central San Luis
Obispo area.
The Central San Luis Obispo and the Airport areas have poor
quality water due to natural or introduced contamination in
places . Also , the Airport area has a large number of ground
water users which could be impacted by the City' s development of
' ground water resources there.
The Laguna Lake area has some ground water resources which are
not heavily used now, but which could be used to benefit the
City's golf course. Rather than recommending the development of
a domestic well in the Laguna Lake area, golf course irrigation
well (s) appear to be a greater benefit to the City in that such
an irrigation source would offset the current demand on the
City's water supply system.
The three areas which hold the greatest potential for ground
1 water development are:
( 1 ) Upper San Luis Obispo Creek area
( 2) Stenner Creek area
( 3) South Central San Luis Obispo area
The Upper San Luis Obispo Creek area could support ground water
production of approximately equivalent to 0. 5 million gallons per
day, MGD 560 acre-feet per year. The Stenner Creek area could
support approximately 300 acre-feet per year and the South
Central San Luis Obispo area could support approximately 1000
acre-feet per year. These estimates are subject to confirmation
during the exploration program.
' These ground water production projections could be increased
through operational conjunctive use methods such as increased
ground water use during winter months when stream flow is
greater. This would allow for increased recharge to the ground
water basin and , therefore , an increased ground water basin
yield. Storage in the surface water reservoirs would be retained
as a result of this practice and be available for use when ground
water sources are less productive in the low stream flow months .
' Increased lake water levels and surface water storage in Laguna
Lake by placing a weir near the outlet has been discussed in the
Laguna Lake Management Plan prepared by the City in 1980 .
1 17
1
Currently, the City places a temporary 12 inch weir at the outlet
every Spring and removes it in the Fall . Raising the weir higher
could result in roughly 200 acre-feet of increased storage per
foot of lake level rise. The water supply benefit from such a
plan would be for recreational irrigation at the Laguna Lake Park
or the junior high school . Since this concept will be more fully
explored in the upcoming wastewater reclamation study being
performed as part of the wastewater management plan and since
this source is not a ground water supply source, this potential
source will not be further discussed in this report .
GROUND WATER EXPLORATION
' The abandonment of old City ground water facilities and the
siting of new well facilities necessitates exploration activities
anticipated in the Phase 3 scope tasks of the agreement between
the City of San Luis Obispo and John L. Wallace and Associates .
The City may still be able to develop wells adjacent to the old
well facilities .
' The exploratory work is focused to determine potential ground
water production and quality at individual well sites . Seven
sites have been selected for exploration based upon availability
and suitability in fitting into the City's system, as well as
other constraints. These sites are located on Figure 3 and are
detailed in a later section.
The exploration program proposed for Phase 3 includes several
soil auger borings, one rotary drilled boring, three test wells ,
three 30-hour pumping tests, and three general mineral and four
organic compound water analyses . The several borings would be
used to determine the most favorable site to locate a well from
' the drilling sites available in the Upper San Luis Obispo Creek
and Stenner Creek areas. The one rotary drilled boring would be
in the Dalidio property to provide a drilling log in- the vicinity
of existing wells for which no record is available. The three
test wells would provide a facility to test well yields and water
quality in each of the three favored areas . The pumping tests
.would give well discharge and water level drawdown information.
' The water quality analyses would provide information on
previously un-tested parameters in these areas, particularly the
organic compound constituents .
L
' 18
J /
/ V ,
i� r
C // ( / UVJ _•
♦ � rim--� J 1 ':"L.
?o � ��.,���>\ �� � �� mii .•;,:``,,f m.�� :d'"�\,J.,�� o � ��J�L�/lit ;t��r� , � 7�,�'
IMP
7 / f ��i� •�� .lam _' jp
y �j r �1�� ,i/'( r , �f • _rr�
�.�(���^,��§rte_ _ • i :' ♦ r���r• ,�''; r �' Lam-�),�-.y l t � rll. �.J\� `,.;.
•I / �'• r, •�40 •M 1. ••.. •�♦ .�� 11���1. 1 �I�` 1'r��I/.� _._r__iJ 7 '`�� `~\ �,
� _J _ tiv�` 'v fir. rl __ N �•
(( 1/•• d�! 1, !-. _'. _
���' l `� � �\`�r �iii'•l: �-_.J i ', f (� f t l d..I�a -r_. 1��- �:
IfT, dr OBl
IIJ
�;� c � �••i� •�Ra1 ! ® " � �-� E .�� Vj�.r h�•w.: ._ 111 � � Ig'
, • �• • � \„/`I,,�• •.\d I •l+� r t �� -. �i�r'Ig1t11 '1 �.. 1 u._-. r:� u �I I
\. 1 v , [ o� `\ k.�� / ' •t ,• �/:. �1(1 �f- �r'/11�I� �! n� rte' • �i ' �w 1��.
00 /:1 % 1'g �`♦ � �• • :( / ^.♦ � \\'1:t• I��- fl1 /11Y !r;`; •� ir^,�i f��.
l• �/s� ._ ...J'y� �l .-$F6 •yl.� �• � f 1� ll��" I �\;;�)il��))iJll / �r�'-1 , .- f , Fi 1�� o. '_ �_
�. �, -, / ' o �' 'V �'I � J .�•1 Y ' f'r s . .�..�J � /�fl�:•. ,�lly �}�I�'i � � �l� � �r OD
.I � +� i, '�:� !"' C (�;`I �r pJr ��.11��11,)��\JI: rgl�lil• `✓ � � -� '��C r.
i / /.; \tom 2`. Il �1�'I ~� 1 � i .:�-.� �•
.I P', \ rn• / ._�''�� r� /,/� �•. ,fJl1�\ ��n\, �� � y +�'% 1 til\```r -) � r.
~:�, l•_ ., ' l, S 'rl�� t�r( kC: <) 5���))� �! ' ' fl `I }Illllhyr(;:�
1 I �' r/ r 1 �' �l \J( ( !t! ,\/)(r`• J,��1 1 �'� � 1 l , ,. � t/ r r."-".ry / ��� 1 `�
•'/ •" �u�� ` .r (�( �1`'� �i �n-= .s It /�• '�/)1 y' 1\i i `l ,tit. ,,5� -, •'D
. . 110 ��: (. "!�'�'• / i \.� 5..�? .!1 0l, l I i/` .il�� 11`itC,1 ��':-_rg��il _ �--
1 O
I m
Q I ^ f
I r N
D
0
O
Lo
y O
Z T
Ce N a Z m
m C r- a m
O W m
N m Y m
O N n
Ems = Z m
m
OD O r
a = m
v
a
a
o m �+
X � —
O o
r "V C .
00 O m
> m w
D ca O O
2 m
r -< M
C r
O
m m m
co a. to
a ;
0
The estimated cost of these tasks would be $32 , 110 and would
entail :
EXPLORATION PROGRAM
CITY OF SAN LUIS OBISPO
1 . 8 Borings - Hollow Stem Auger
' 2 . 1 Boring - Rotary Drilled
3 . ( 2) 8" diam. Test Wells (PVC)
4 . ( 1 ) 12" diam. steel Test Well
5 . (2) Electric Logs of 200' Borings
6 . ( 2) Pumping Tests, 80 ' setting
T . ( 1 ) Pumping Test, 200 ' setting
8 . Water Quality Analyses
(3) General Mineral , provided by the City
(4) Priority Pollutant
(4) Total Organic Halogen
( 4) Title 22 Organics
WELL SITING CONSTRAINTS ANALYSIS
In examining each of the seven selected sites, siting constraints
such as access, location relative to the City's existing water
distribution system, and required setbacks were taken into
account . For example, current regulations state that domestic
water wells must be set back at least 50 feet from sanitary sewer
facilities and 50 feet from the banks of creek channels and other
surface water ways . A 50 foot setback from existing wells is
also recommended . In addition, constraints in the actual
drilling operation were considered such as the need to stay clear
of overhead utility lines ( 20 feet setback minimum) and other
overhead obstructions . .
Also discussed in this section is the need for blending to
achieve desirable water quality . Anticipated well discharge
rates and total hardness at each site are estimates only and will
be refined as actual test results become available.
With regard to water quality, the introduction of well water into
the City ' s system may be noticed by consumers due to the
relatively high levels of hardness. Specifically, total hardness
of the City water supply now is about 200 mg/1 .
20
The proposed well sites may have hardnesses ranging from 330 to
460 mg/l . Although there is no maximum recommended level of
hardness established by the State, it is recognized that "hard"
water causes accelerated corrosion of . pipes, hot water heaters ,
etc. , and may have an objectionable taste.
To address this issue, it is recommended that well discharge be
blended. Our suggested goal is to blend to a maximum of 300 mg/l
total hardness since this does not significantly vary from the
City' s current water quality. This is not meant to imply that
300 mg/l is a recognized break point between palatable and
objectionable water. This is simply presented as _ an achievable
level of quality from a hydraulic stand. point.
Constraints associated with each site are discussed below and are
illustrated in Figures 5 through 11 . Table 2 is a summary of the
findings at each of the seven sites .
Upper San Luis Obispo Creek:
Old Reservoir 31 Site: Continuing northbound onto Highway 101
from the Monterey Street on-ramp is the Old Reservoir #1 site
(Figure 5) which is a City-owned parcel .
Ground Water Development Limitations : Little constrains the
development of a well at the Old Reservoir #1 site. The City has
no wastewater facilities in the vicinity with the exception of a
septic tank and leach field at the Police Department training
facility which was built in 1985 . The tank and leachfield are
situated to the west and south of the training structure. A well
at this site would have to be set back a minimum of 50 feet .
Also, a well at this location would have to be located at least
50 feet from the San Luis Obispo Creek channel to the south. The
area between the tower and the structure may be well-suited for
drilling, plus the area immediatley to the west of the reservoir .
Old Reservoir #1 was abandoned in the 1941 and has since been
replaced by a 7 .5 million gallon (MG) reservoir across Highway
101 . The original 14 inch steel transmission main which runs to
the north of Old Reservoir #1 is still in use.
Overall , the Old Reservoir #1 site appears to be a good location
for the development of a City well .
Water Quality and Connection to City Water System: Water quality
data for various areas throughout the City and for the existing
City water supply is listed in Table 1 . Samples gathered along
the Upper San Luis Obispo Creek indicate a total hardness of
about 330 to 392 mg/l which is high when compared to total
hardness in the existing City water supply system of about 200
mg/l .
21
1
----------------------------------------
1 qT a+ N L 1
y b N w m m E T N
1 I L 3 L O) N E m O # 3 L m m 1
1 CA 1 w O w N C m L L L O w L 1
1 H 1 m •r m L m m 0 T to m • L t
1 1 m Y fi m T Y L Y Y L Y E m ++ C q N m t
1 1 O C O V L Y q C O V ^ Y L ^ V L - 1
1 6 1 C q L C ^ q Y ^ m m L C F q 0 r m r 1
1 LC 1 q i+ W q n L V V q ^ V in J 3 0 1
^ O V O L L q J L N q 1
^ m
\ N L 1
1 O 1 L C O m m ^ m 0 OI m 1
I U 1 V Cl w V ^ L N q q E V #
m •+a 'r ^ o 1
1 1 m L m T m m O L N I
1 W 1 C N N C 7 L m C C L q N C 3 �+ m � O 1
1 H I q T V 9 •r q q q •r C L r•••
Co0
C Y I
1 1 q m q q q q 0 c O J 1
1 to 1 V Y V Y L L
1 1 C
Iwo
10T c m V T C $ ^ ` y C N L m Y L L ^ 1
C q N
is z v m i 4e a to i i m d .L+ m xJ 03 s i
--------------------
gm
co w
--------------------
1 Z b b b b b m m N N 1
1 OC I ^ N F N m
1 1 ^ I
---- ----------------------------------
0 8 W
I 1 TNm no no i MJ�I1�
1 1 L 8\ d S C E N \ C N \ 1 W
n m fi 1 Q
I O 1 q T 1 m w Y m C m C 1
1 W I O m C b • � r L b r L m 1 r
1 O 1 1? •r N O F q q f q f 1
1 Z 1 m t q ^ N N I L 1 L 1
I tO 1 m m 1 •r y �+ O y Y \ •.- q 0 q 0 ;
1 1 L v e v �' fi o Vf y o i a
i •Y~.. i d t0 a+ a.• C n a+ CI
1 1 m i m^ m N m m
1 J 1 � C N C N O O C •� 1
1 < 1 IA O C
0
I W 1 PO'I
CD
m
Q L L O
1 x z 1 w v •.• 0 0 e 1 N
1 W 1 O m O m O m O 1 N
1. CL
Q 1 N X N V N X N 1
1 3 1 N m 1 N m N m 1 N b 1 1
1 1 m m m n C m m m 1 J
1 1 C 6 C X C ^ E C E 1
1 J 1 � \ q y m � \ q v 0 q 1
1 W 1 L N L
3 �L�pp T N L N 1 J
1 i L � 1 L \ L E I L G
1 < 1 N ^ E ^ m Y I
1 CY. 1 q N q q Rf q •• m 1
1 1 O O O m O O O b X 1
1 I Y'
1
i v i = n n n n n n i Z
i aWC i x x S x x S x I
in
I I N b t0 1
1 p cc`
1 W I I L
1 Cl• 1 -------------i
r
r l I I a• y .
1 C1 � 1 Y L Y Y v 4.• Y 1 q
1 W Q I m m m m m m m I O
1 CY W 1 m m m m q m m 1
1 H 2 1 •H •H •F W W W W I T
6 ^ J
---------------------------- Y --------- O•
1 1 W n n C1 n O n 1 Y• L
1 H V 1 Q O O O O O O O OI 1 # O
1 to 1 O O O O O O O O I L
` I W 1 b b llf O O O v O O 1 v n
-------------------
1 n 1 v q Q
1 H 1 Y m m m m m N m m 1 L
1 J 2 1 W Y y Y L L M Y 1 q L
I J W 1 W ^ ^ ^ •r + m T 1 L O
N N 1
X
1 O to1 O O q O O O O I ++ m
1 < I H GGGDDD CCC��� tO�f IL C7 C7 J U' O 1 J O
^ O •• o4y O I S•�
m CD
i H 1 Z L CME
1 O 1 m W E C C U O i L t7
1 J 1 W m = O
' 1 1 n Yp W LC L L
1 1 O O N 6 ---Ci000 --U. V D 1 M
-------------------- -------------
r
1
To mitigate this difference in total hardness, a well at the Old
Reservoir #1 site should be piped directly to the 7 . 5 MG
reservoir across Highway 101 . This would require approximately
1 , 300 feet of 6 inch diameter pipeline and a pumping head of
roughly 140 feet ( 61 psi) for an 11 horsepower (Hp) well pump.
At one time, a steel transmission line ran from the Old Reservoir
to the current reservoir location across Highway 101 . It may be
' practical to slip-line this existing line for use as a well
discharge line rather than to construct a new line and highway
crossing. This possibility should be explored further as part of
the design phase.
No other special treatment processes appear necessary at this
site.
Motel Inn: The Motel Inn (Figure 6) on Monterey Street near the
Highway 101 on ramp is a privately-owned parcel which may be
suitable for a well site.
Ground Water Development Limitations: The southeast portion of
the Motel Inn parcel may be suitable for well development , where
the property borders along San Luis Obispo Creek. Constraints
involved in drilling here include the need to maintain a minimum
50 foot setback from the creek channel and the need to obtain an
' easement from the owner. Also, to blend this water properly,
pumping from a well at the Motel Inn would have to be restricted
to night time pumping only.
The west end of the property is an asphalt parking lot with dense
vegetation bordering the creek channel . Maintaining the required
creek setback and avoiding the vegetation may require that a well
be drilled in the paved area of the parking lot .
Also , overhead utility lines border the southeast edge of the
parking lot , impairing a drilling operation off of the edge of
pavement .
Overall, the Motel Inn site appears to be good location for well
development .
Water Quality and Connection to the City Water System :
Anticipated total hardness at this location is about 330 to 392
mg/1 which is high when compared to the current City water supply
hardness of approximately 200 mg/1 .
` Blending is recommended to mitigate the impact of introducing
relatively hard water into the system. To do this, a well on the
Motel Inn site could be piped into the 14 inch diameter line in
Monterey Street.
23
Flows in this pipe follow a diurnal pattern with flow entering
the system from the City's 7 . 5 MG reservoir during the day and
filling the reservoir during the night . Operating the proposed
well during the night time fill condition would ensure proper
blending at the reservoir before entering the distribution
' system.
The 14 inch diameter steel transmission main in Monterey Street
in front of the Motel Inn which is within the City' s 433 feet
pressure zone . Approximately 250 feet of pipeline would be
needed plus a pumping head of about 188 feet ( 81 psi ) , for a 15
Hp well pump.
Stenner Creek:
Anholm Site: The Anholm site (Figure 7) is on a City-owned
parcel near the intersection of Chorro and Mission Streets, at
870 Mission Street. This approximately 5, 750 square foot lot is
in a residential neighborhood and is currently used as a
playground.
Ground Water Development Limitations: The biggest constraint in
developing a well on this parcel is the need to maintain a 50
foot minimum clearance from wastewater facilities. A 6 inch
sewer runs 10 feet north of the centerline of Mission Street ,
requiring a well to be 60 feet or more north of centerline. This
' would put the well inside the fenced play yard.
Also, the sewer service laterals on the adjacent lots would need
to be located and a 50 foot clearance maintained. This further
narrows the available area for well development to the center of
the parcel .
A well developed on this lot would require that the existing well
be sealed according to Health Department standards, possibly by
pouring a 50 foot concrete seal .
The fenced play area is set back approximately 55 feet from the
street centerline . Within the fence are numerous trees that
shade most of the lot and which would impair a drilling
operation. It is likely that one or more trees would have to be
cut down, or at least trimmed, to drill a well here. Also, part
of the existing chain link fence would have to be taken down to
Laccess the back of the lot .
Another constraint associated with the Anholm site is that
overhead wiring crosses the driveway. This may impair a drilling
rig from entering the lot .
The Anholm site rests in a residential area and neighborhood
reaction to both the drilling operation and the presence of well
facilities on this lot are to be considered.
' 24
1
1
Overall , numerous constraints are associated with developing a
well on the Anholm site due to the inaccessibility associated
with the need to maintain 50 foot clearance from wastewater
facilities.
Water Quality and Connection to the City Water System: Tests at
the Anholm site indicate that ground water quality is generally
good and that special treatment methods should not be required.
Blending may be desireable, however, due to the relatively high
total hardness (380 mg/1 ) .
Flows in the surrounding distribution system are relatively small
under normal demand conditions. Introducing ground water into
the 8 inch line in Mission Street may result in an undesired,
localized increase in water hardness. To avoid this, an in-line
' pump could be installedto pass a total combined flow rate of
about 700 gpm. For a 250 gpm well at the hardness stated above,
the resulting water hardness would be about 268 mg/l . This is
much closer to the existing City water hardness of about 200
mg/1 .
A well at this location would discharge into the City's "Downtown
Pressure Zone" which operates at a static head of 385 feet .
About 70 feet of 6 inch diameter line would be needed to make the
connection . This lot rests at about elevation 220 feet ,
t requiring possibly 236 feet of pumping head ( 102 psi ) for a 15 Hp
well pump.
' Community Garden: The Community Garden site (Figure 8) is also
on a City-owned parcel at the intersection of North Broad Street
and Lincoln Avenue near the Highway 101 on ramp. Currently,
parcel is undeveloped and is used as a garden area for City
' residents.
Ground Water Development Limitations: The principal constraint
in developing a well on this parcel is the need to maintain a 50
foot clearance from both the existing 6 inch sewer line in North
Broad Street and from the Old Garden Creek and Stenner Creek
' channels. A well on this site is likely to have to be protected
from flood hazard possibly by extending the well casing several
feet above ground. Also, a considerable amount of piping would
need to be installed to connect to the surrounding distribution
' system.
Little else would restrict well development at the Community
I Garden site . No existing structures nor overhead power lines
would obstruct a drilling operation.
25
' Since the site rests in a residential area and is currently used
by the public , neighborhood reaction to both the drilling
operation and the presence of well facilities on this lot are to
be considered.
Overall , the Community Garden appears to be a good location for
well development .
Water Quality and Connection to the City Water System: Total
' hardness measured at several Stenner Creek wells ranged from 300
to 380 mg/l and an iron (Fej concentration of 0 . 265 mg/1 .
Although neither constituent exceeds current MCL, both may render
t the water aesthetically unpleasant to consumers.
For this reason, a well at the Community Garden site is not
recommended to be piped into the surrounding 6 and 8 inch
' distribution system. Rather, a line should be constructed to
connect the well to the Hill Street 20 inch which normally flows
at approximately 1 , 520 gpm. A 200 gpm well blended at this point
would result in water with a total hardness of about 224 mg/l and
an iron concentration of about 0.035 mg/1 .
' About 700 feet of 6 inch . diameter line would be needed to make
this connection.
The 20 inch diameter distribution main in Hill Street is part of
the 431 feet pressure zone. At an elevation of about 185 feet ,
this would require possibly 319 feet ( 138 psi ) of lift for a 20
Hp well pump.
rFerrini Site: . The Ferrini Site (Figure 9) is also a privately-
owned parcel along Highway 1 across from property owned by the
' California Polytechnic State University. Adjacent to this
parcel is the City's Ferrini pump station which boosts water over
the hill through the Ferrini Tract and up to an existing
reservoir .
' The existing water distribution system in this vicinity offers a
good opportunity for blending well water of lesser quality.
' Ground Water Development Limitations: The biggest constraint in
developing a well at the Ferrini site is the need to obtain an
easement from the property owner.
There are no sanitary sewer facilities in the vicinity of the
potential well site. There are some overhead utility lines which
' could easily be avoided plus an existing well to avoid.
The Ferrini site appears to be a good choice for well
development.
' 26
1
Water Quality and Connection to the City Water System: Water
samples taken from the existing Ferrini well indicate a total
hardness of 364 mg/l and an iron (Fe) concentration of 0 . 265
mg/1 .
A well at this location would discharge into the existing 27 inch
diameter line in Highway 1 . About 250 feet of 6 inch diameter
line would be needed to connect to this line which normally flows
at 2 , 440 gpm. For a 200 gpm well , the hardness of the combined
' flow would be about 215 mg/l and the iron concentration would be
about 0.022 mg/l . No other special treatment appears necessary
at this site.
' The suction line is in the 431 feet pressure zone, requiring
about 184 feet (80 psi) of lift for a 12 Hp well pump.
South Central San Luis Obispo:
Corporation Yard: The City Corporation Yard (Figure 10) along
Highway 101 at Prado Road may be suitable for a well site . San
Luis Obispo Creek runs through the property.
Ground Water Development Limitations: A City bus parking area is
under construction in the northwest corner of the Corporation
Yard. This area appears best suited for well development , most
of which will be asphalt pavement .
Water Quality and Connection to the City Water System: Water
samples taken from the existing Dalidio Well #2 across Highway
101 from the Corporation Yard appear to be the best source of
water quality data . Well water here tested higher than the
established recommended MCL in total dissolved solids . Total
hardness was tested to be 460 mg/l which is high when compared to
the City hardness of 200 mg/1 .
The TDS of 670 mg/l and the hardness may be addressed by blending
' which could be accomplished by introducing the well discharge
line into the 12 inch water line on Prado Road.
' With the existing distribution system, the 12 inch in Prado Road
normally carries little flow. An in-line pump is recommended to
provide substantial blending water. For a 600 gpm well operating
in conjunction with a 1 , 000 gpm in-line pump , the blended
hardness would be about 298 mg/l and the combined TDS would be
approximately 463 mg/1 .
' The Corporation Yard is in the City's 345 feet pressure zone.
Approximately 870 feet of 8 inch diameter line would be needed to
connect to the 12 inch in Prado Road . At an approximate
elevation of 129 feet , 312 feet ( 139 psi ) of lift would be
required, for a 60 Hp well pump.
' 27
Dalidio Site: The Dalidio site (Figure 11 ) is a privately-owned
parcel between Highway 101 and Madonna Road, south of Madonna
Plaza. Four agricultural wells plus one domestic well ( the
Embassy Suites well) are in operation on this parcel .
' Ground Water Development Limitations : Little constrains the
development of a well on this property with the exception of the
need for the City to obtain an easement from the property owner
and the distribution system improvements which may be needed in
' the vicinity of a new well .
Wastewater facilities border the property on three sides ,
' however, maintaining the minimum 50 foot setback leaves much of
the property available for possible drilling.
Overhead high voltage power lines cross the eastern end of the
' property and are to be avoided while drilling.
Overall , the good production rates and availability of suitable
' land for well development makes the Dalidio site a good choice
for pursuing a City well .
' Water Quality and Connection to the City Water System: Water
samples taken from the existing Dalidio Well #2 tested higher
than the established MCL in total dissolved solids (670 mg/1 ) and
relatively high in total hardness (460 mg/1) .
The TDS and hardness may be mitigated by blending which could be
accomplished by introducing the well discharge line into the 12
inch water line on Highway 1 .
With the City's existing distribution system in this vicinity,
circulation near the proposed well site is relatively low volume.
To improve circulation, the 12 inch line in Highway 101 should be
extended from Prado Road along the southern Dalidio property line
(approximately 1 , 350 feet) and an in-line pump installed.
For a 600 gpm well operating in conjunction with a 1 , 500 gpm in-
line pump, the resulting TDS would be 434 mg/l (recommended MCL =
500 mg/1 ) and the total hardness would be 274 mg/1 .
The operation of this pump would have to be coordinated with the
proposed Corporation Yard pump, both of which would discharge
near the intersection of Highway 101 and Prado Road.
A City well at this site would discharge into the 345 feet
pressure zone. At approximately 120 to 130 feet elevation, about
316 feet ( 137 psi ) of lift would be needed, for a 60 Hp well
PUMP
' 28
' FIGUR€ 4
' LEGEND TO SITE MAPS
' FIGURES 5 THROUGH 11
' Property Line
-8• g� Approx. location of sewer line, dia. in inches
Manhole.
Cleanout
r
—�— Lift Station
—a• W— Approx. location of water line, dia . in inches
Utility pole w/ overhead utility lines
Approximate creek location
: ; `" Approx. edge of setback
1
1
1
i --.Q;;jjz-Z--mm!!M
1 N.T.8.
1
t
:4pq
9 A Om��
1 v
tip LD RESERV
yep+
OSBEAVATION
' TOWEN
SELECTED
WELL
' DEVELOPMENT ❑
AREA
POLICE
PACILITV
P I HOUSE
G{.
OLD PIPELINE
' 4
O
1
JOHN L.WALLACE &ASSOCIATES OLD RESERVOIR 1 FIG. 5
CONSULTING CIVIL ENGINEERS
1
1 60
' SELECTED .'
•WELL
OEVELOPYENT
AREA
r
1p
•
's
9y � f
yG�G RFt
F FC
e,
s• s,
� s• 8 PNON '
i
BUENAISTA s•
AVENUE
�O
F`
8rq�
F�
JOHN L.WALLACE&ASSOCIATES MOTEL INN FIG. 6
' CONSULTING CIVIL ENGINEERS
1
Ak All
NOW
1 -N-
TRACT NO. 110
M.T.S.
1
0_ 0 0 0
O
1 , I
01
OIN I
I
MOUSE MOUSE I
.. ..:.. ..... ;::...:...............:. .. . . ..
% :Isis;i;'.';i�;;.,;,.�:,:.,::;:..,
1 i
i
1 v V O
1 60
1 009® o
20 9• S A.
-�-�-MISSION --- STREET
e• w
1
1
i
i
' JOHN L WAUACE& ASSOCIATES ANHOLM SITE FIG. T
CONSULTING CIVIL ENGINEERS
1
1
3
a LlNCpLN
e• s ,e,
n W
� A vEN�E � No
4
Ju
OD
\ Y•
0
Oi � SO
�6
4
Oma° a1
'/EELECTEO WELL
6YELOPIIERT ARE :`
:.,.. O
• 3
� e
'
' •b/ ;:'
1 �a w
1
JOHN L. WALLACE &ASSOCIATES COMMUNITY GARDEN FIG. 6
CONSULTING CIVIL ENGINEERS
Amilk
1 }
�m=EgiiE z emm�
1 0 :
po
p.T.s.
fir•`.
- tP
as /
SAO WT
' s PUMP HOUSE
f
ggFF�FR sELecreO WELL w • IN
OEYElOPYBRT ARE -tt•,"":"'+"' .,.
31 :{
O ti:
1 lC
1
JOHN L. WALLACE& ASSOCIATES FERRINI SITE FIG. 9
' CONSULTING CIVIL ENGINEERS
1
1
1 t
2• 4 S d0
. .......::.::.
{;# FIRE
1eouAuz
:; DEPT.
CORPORATION YARDS TRAINING BASINS
� 'jj FACILITY
.I
16 v..n::.
3aLacTeO WELL
OavaLOwaNT AREA
1 ai WASTEWATER
TREATMENT
e
?'_'i::'�3:•v:��� PLANT
r II A
1 II
1 Fu"Re Bus _ o
ram"uNo
1 • i'!G
31O
x <{:`" EFFLUENT m
E's DISPOSAL
AREA
1v
LIFT a �: � N.T.S.
_ — 0• :• STATION
X.
J I
?i$
SILVER CITY
1 TATION
uFT a
I �•
1ENRON
' JOHN L WALLACE & ASSOCIATES CORPORATION YARD FIG. 10
CONSULTING CIVIL ENGINEERS
LAGUNA LAKE
' 6•��MgD al x
rr
b
W I 9•\ q _
OIm s '?may,
1 WS • .11• s// N.7.S.
20 • S m
1
�pdp 1100. 4?
ROAD
' G 1 POST
CAYUCOSO ,;:. ` p�Er 10 1 E 3 Z 6• s
Oa
O
N
N
�} O
1 a
loo'
W
U
W
SELECTED WELL
DEVELOPMENT AREA
n
EXISTING WELL
60• SETBACK
• w
' X01
+s' w e• S HwY \
' 8• F 0. FM
LS
a
v
' (SEE CORPORATION YARD) O
� O
1 Iv
JOHN L. WALLACE & ASSOCIATES DALIDIO SITE FIG, y I
' CONSULTING CIVIL ENGINEERS
1
1
1
1
1
1
APPENDIX
1
1
1
1
1
I
1
1
I
1
1
1
ACKNOWLEDGMENTS
Input for this study has been obtained from many individuals who
area noted hereunder . Their assistance has been greatly
' appreciated.
Mr. Dave Romero City of San Luis Obispo
Mr . Bill Hetland City of San Luis Obispo
' Mr. Hal Fones City of San Luis Obispo
Mr . Mike Multari City of San Luis Obispo
Mr . John E. Moss City of San Luis Obispo
' Dr. Doug Gerard California State Polytechnic
University
Mr. Gary Ketcham California State Polytechnic
' University
Mr. Burt Polin
Mr. Ernie Dal.idio, Sr.
Mr. Ernie Dalidio, Jr.
' Mr. Andrew G. Merriam Merriam Planning Associates
Mr. John L. Merriam
Mr. Robert Brown
' Mr. Glenn Britten County of San Luis Obispo
Mr. Einer Anholm
Mr. John Cheda
Embassy Suites Hotel
' Mr. Felton Ferrini
Mr. and Mrs . Milt and Betty Grau Motel Inn
84 Lumber
Mr. Joe Bautista Farm Supply
Mr. Brian Nielsen California Department of
Health Services
' Ms. Perry Garfinkel California Department of
Health Services
Mr. Fred Fernemberg Cal Trans
Mr. Karl Seckel Municipal Water District of
' O
Mr . Al DeVaul range County
1
1
1
1
REFERENCES
' California Department of Water Resources , 1958 , State Water
' Resources Board Bulletin No . 18 , Volume 1 , San Luis Obispo
County Investigation
California Department of Water Resources, 1969 , Water Quality
' Conditions, Coastal Region, San Luis Obispo County, Report
to Central Coast Regional Water Quality Control Board
' California Division of Mines and Geology, 1973 , Map Sheet 24 ,
Geology of the Arroyo Grande. Quadrangle
' City of San Luis Obispo, 1982, Laguna Lake Management Program
City of San Luis Obispo, 1986, Draft Water Management Plan
' Cleath, Timothy S. , 1978, Ground Water Geology of the San Luis
Obispo Area, Master's Thesis, California State University,
Los Angeles
' Cleath, Timothy S. / Willdan Associates, 1986, Ground Water Study,
San Luis Obispo Airport Area prepared for County of San Luis
Obispo
' County of San Luis Obispo, Well Data Files
' Engineering-Science, 1977, City of San Luis Obispo Water Supply
Study
' George S. Nolte and Associates, 1977, Flood Control and Drainage
Master Plan for the San Luis Obispo Creek Watershed, Zone 9/
San Luis Obispo County Flood Control and Water Conservation
District
' Jenks & Adamson/Kingman Engineers , 1972 , Report on Interim
Municipal Waterworks Improvements to Alleviate Los Osos
' Valley Water Supply Problem
Merriam, John L. , 1986, Reconnaissance Study of Central Portion
' of San Luis Obispo Sub Basin and Dalidio Property
Moss, John E. , 1987, San Luis Obispo Wastewater Treatment Plant
Water System Evaluation and Well Analysis, prepared for
' Agricultural Engineering Course 500, California Polytechnic
State University, San Luis Obispo
' Penfield & Smith, 1973 , Los Osos Valley and Lower Higuera Area
Water Systems Improvements City of San Luis Obispo
' 2
1
1 --
Ryder, R.W. , 1922, Report on the Water Problems of the City of
San Luis Obispo
U . S . Army Corps of Engineers Los Angeles District California,
1974 , Flood Plain Information , San Luis Obispo and
' Tributaries, Vicinity of San Luis Obispo, San Luis Obispo
County, California
U.S. Department of Agriculture Soil Conservation Service, , 1983 ,
' Soil Survey of San Luis Obispo County, California, Coastal
Part
' U. S . Geological Survey, 1978, Miscellaneous Field Studies Map
MF-686 , Geologic Map , Cayucos - San Luis Obispo Region,
California, Sheet 1
1
1
1
1
1
t 3