eki environment
water
A monitoring location at the McKinley Avenue Pump Station wet well ( Figure 7), to capture the sewershed that is served by the Woodfield Pumping Station, California Natural Products Pump Station, and McKinley Avenue Pump Station.
A schematic of the sewersheds captured by the meter locations is shown on Figure 8.
Sampling equipment was installed by EKI' s subconsultant, Total Flow, Inc. (TFI) in each of the six monitoring locations, while flow monitoring equipment was installed in one of the monitoring locations, specifically at the O Street manhole location ( Figure 5). Samplers were set to collect 24 -hour composite samples on approximately 20 -minute increments. The flow monitoring equipment was set by TFI to monitor flow at five- minute increments.
Composite samples were collected on the following dates:
10 October 2022 ( Monday) 1;
16 October 2022 (Sunday);
20 October 2022 ( Thursday); and
28 October 2022 ( Friday).
Composite samples were analyzed by FGL Environmental ( FGL) laboratories located in Santa Paula and Stockton, California. Samples were analyzed for the following constituents:
BOD by Standard Method ( SM) 5210B;
TSS by SM 2540D; and
TKN by EPA Method 351. 2.
MONITORING RESULTS
Results from the four sampling events are summarized in Table 1. Results from the flow monitoring at the O Street sanitary sewer manhole are provided in raw form in Attachment A and are summarized in Table 2 and Figures 9 through 13.
As shown in Table 1, there was relatively little variation in BOD, TSS, TKN concentrations across the six monitored locations. The average BOD concentrations across all sampling events were all within a relatively narrow range between 214 milligrams per Titer ( mg/ L) and 311 mg/ L, while TSS and TKN concentrations also did not vary widely. There also did not appear to be any consistent correlations between concentrations and the day of the week that the sampling occurred. 1 Due to an unanticipated sampling equipment issue, a sample could not be collected from the O Street PS location on 10 October 2022.
EKI C20049. 02
Greg Gibson, P. E.
City of Lathrop
DRAFT —13 December 2023
eki environment
water
One observation is that while BOD and TKN concentrations in the collection system samples were generally similar to concentrations typically measured from the Lathrop combined influent samples that are collected at the WQCF, the TSS concentrations in the collection system were generally significantly lower than the concentrations from the WQCF samples. The cause of this discrepancy is not immediately known.
As shown in Table 2, the daily flows at the O Street Pump Station appeared to increase later in the month, with slightly higher flows observed on weekends as compared to weekdays. As shown on Figures 9 through 13, the diurnal patterns in the flow generally were consistent with what would be expected, with flows being very low during the midnight to 6 am portion of the day and weekday flow peaks observed in the early evenings.
DISCUSSION AND CONCLUSIONS
One original goal of this monitoring was to evaluate whether there are portions of the collection system that may be higher contributors to BOD, TSS, and TKN loading at the MWQCF, with the hope that portions of the wastewater flow could possibly be rerouted to the City' s Consolidated Treatment Facility ( CTF). As shown in Table 1, the sampling indicated that BOD, TSS, and TKN concentrations were relatively uniform across the various sewersheds. As a result, the monitoring did not identify any specific sewersheds that could be specifically targeted to redirect a disproportionate amount of BOD, TSS, and/ or TKN mass to the CTF.
EKI C20049. 02
DRAFT - Table 1
Sampling Results from Composite Samples Collection from Wastwater Collection System u
Y " i' 9 Y
fZi*
Sampling Location ` l Date ; O w :
u;
q
v
North Harlan Pump Station
10/ 2022 231 63 68
10/6/ 2022 224 55 54
10/ 20/022 273 49 95
10/ 28/022 222 133 100
Average - North Harlan Pump Station 238 75 79
Stonebridge Lift Station
10/0/ 2022 211 50 13
10/6/ 2022 222 44 50
10/ 20/022 260 41 45
10/ 28/022 208 260 46
Average - Stonebridge Lift Station 214 99 39
Woodfield Pump Station
10/ 2022 286 73 13
10/6/ 2022 295 68 62
10/ 20/022 282 62 57
10/ 28/022 288 86 59
Average - Woodfield Pump Station 288 72 48
O Street Santiary Sewer Manhole
10/ 2022 238 30 12
10/6/ 2022 265 32 56
10/ 20/022 269 34 54
10/ 28/022 221 32 47
Average - O Street Sanitary Sewer Manhole 248 32 42
O Street Pump Station
10/6/ 2022 310 86 61
10/ 20/022 260 67 52
10/ 28/022 312 123 53
Average - O Street Pump Station 311 92 55
McKinley Pump Station
10/ 2022 212
137
312
49 52
41 17
160
28 10/6/ 2022
10/ 20/022
10/ 28/022 270 63 33
Average - McKinley Pump Station 233 51 60
Abbreviations:
BOD = biochemical oxygen demand
mg/ L = milligrams per liter
TKN = Total Kjeldahl Nitrogen
TSS = total suspended solids
City of Lathrop
December 2023
EKI B60038. 00
DRAFT - Table 2
Summary of Flow Monitoring Results from O Street Sanitary Sewer Manhole Sample Date Day of Week
Flow ( MGD)
Average Minimum Maximum
10/ 5/ 2023 Wednesday 0.341 0.094 0.671
10/ 6/ 2023 Thursday 0.306 0.045 0.648
10/ 7/ 2023 Friday 0.382 0.037 0.889
10/ 8/ 2023 Saturday 0.403 0.089 0.795
10/ 9/ 2023 Sunday 0.379 0.066 0.862
10/ 2023 Monday 0.379 0.065 0.846
10/1/ 2023 Tuesday 0.398 0.021 0.761
10/2/ 2023 Wednesday 0.397 0.059 0.799
10/3/ 2023 Thursday 0.408 0.099 0.860
10/4/ 2023 Friday 0.396 0.111 0. 1072
10/5/ 2023 Saturday 0.432 0.101 0.992
10/6/ 2023 Sunday 0.414 0.096 0.888
10/7/ 2023 Monday 0.439 0.119 0.822
10/8/ 2023 Tuesday 0.410 0.083 0.774
10/9/ 2023 Wednesday 0.408 0.087 0.849
10/ 20/023 Thursday 0.419 0.051 0.887
10/ 21/023 Friday 0.416 0.075 0.784
10/ 22/023 Saturday 0.531 0.120 0. 1186
10/ 23/023 Sunday 0.460 0.110 0.933
10/ 24/023 Monday 0.407 0.115 0. 1097
10/ 25/023 Tuesday 0.427 0.076 0.932
10/ 26/023 Wednesday 0.452 0.095 0.891
10/ 27/023 Thursday 0.442 0.078 0.918
10/ 28/023 Friday 0.426 0.070 0.841
10/ 29/023 Saturday 0.444 0.064 0.954
10/ 30/ 2023 Sunday 0.454 0.076 0.927
10/ 31/ 2023 Monday 0.446 0.120 0.915
Month of October ( not including partial days) 0.415 0.021 0. 1186 Mondays _ 0.418 0.065 0. 1097
Tuesdays 0.413 0.021 0. 1186
Wednesdays 0.400 0.059 0.891
Thursdays 0.394 0.045 0.918
Fridays 0.405 0.037 0. 1072
Saturdays 0.452 0.064 0. 1186
Sundays 0.427 0.066 0.933
Abbreviations:
MGD = million gallons
City of Lathrop
December 2023
EKI B60038. 00
North Harlan PS
Monitoring Location -/ ;
Figure 2)
1 i
r
I
Valley Crossings LS L.
O St SSMH
Monitoring Location —
Figure 5)
CLSP PS
1 River Islands
Permanent PS
I/
OStPS
Monitoring Location
Figure 6)
Stonebridge LS
Monitoring Location
Figure 3)
Woodfield LS
Monitoring Location
Figure 4)
California Natural
Products PS ( Privet)
iIATHROP RD
j McKinley Ave PS
Monitoring Location
i (Figure 7)
T.' f LOUISE Ay
SSI PS
e ( Private)
O
I
r
Lathrop MWQCF l
Flow Meter
LIP PS
Private) :
s_i.. , y°SEMITE AV
Lathrop Gateway
fIIIy MWQCF
j2, I
Lathrop ' iv
CTF
HERE, Germin, lc) OpenSthetMep con0lbu[ on, and the OIS use f.c:-.!Sphere of Influence
Appoximate Area of WWT
Pump Station or Lift Station
Force Main
Gravity Main
Abbreviations
CLSP = Central Lathrop Specific Plan
CTF = Consolidated Treatment Facility
LIP = Lathrop Industrial Park
LS = Lift Station
MWQCF = Manteca Water Quality Control Facility
PS = Pump Station
SSI = Super Store Industries
WWTF = Wastewater Treatment Facility
SSMH = Sanitary Sewer Manhole
Notes
1. All locations are approximate.
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, 23 September 2022.
N o 2, 500 5, 000
Scale FFeet)
Flow Monitoring Locations
Q environment
i ( & water
Orly or Lathrop
Lathrop, CA
December 2022
EKI C20005. 02
Figure 1
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Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, 29 April 2021.
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MIN -- Force Main
Gravity Main
Notes
1. All locations are approximate.
N 0
A
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Scale in Feet)
Flow Monitoring Location -
North Harlan PS
e I
environment
water
City of Lathrop
Lathrop, CA
December 2022
EKI C20049. 02
Figure 2
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Gravity Main
Notes
1. All locations are approximate.
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, 29 April 2021.
ti 0 300 600
Scale in Feet)
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Flow Monitoring Location -
Stonebridge PS
environment
water
City of Lathrop
Lathrop, CA
December 2022
EKI C20049. 02
Figure 3
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Force Main
Gravity Main
Notes
1. All locations are approximate.
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, 29 April 2021.
NA 0 300 600
Scale in Feet)
eki
Flow Monitoring Location -
Woodfield LS
environment
water
City of Lathrop
Lathrop, CA
December 2022
EKI C20049. 02
Figure 4
Ei
Sources
1. Aerial photograph provided by ESRI' sArcGIS Online,
29 April 2021.
2\ 05\ Fiq5
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Legend
Pump Station or Lift Station
Force Main
Gravity Main
Notes
1. All locations are approximate.
A
0 300 600
Scale in Feet)
Flow Monitoring Location - O St SSMH
eki environment
water
City of Lathrop
Lathrop, CA
December 2022
EKI C20049. 02
Figure
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Force Main
Gravity Main
Notes
1. All locations are approximate.
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, 29 April 2021.
u
0 300 600
Scale in Feet)
Flow Monitoring Location -
O Street PS
e
environment
water
City of Lathrop
Lathrop, CA
December 2022
EKI C20049. 02
Figure 6
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Legend
Pump Station or Lift Station
Force Main
Gravity Main
Notes
1. All locations are approximate.
Sources
1. Aerial photograph provided by ESRI' sArcGIS Online,
29 April 2021.
ti 0 300 600
Scale in Feet)
Flow Monitoring Location -
McKinley Ave PS
eki environment
water
City of Lathrop
Lathrop, CA
December 2022
EKI C20049. 02
Figure 7
North
Harlan PS ( a)
River Islands
Permanent
PS ( Future)
CLSP PS
Future)
South
Lathrop PS
Future)
Mossdale
Intertie
Stonebridge
LS ( a)
Woodfield
LS
Valley
Crossing LS
Easy Court
LS
Crossroads
PS
Lathrop
Gateway PS
Future)
1 Street PS
O Street PS
LIP PS
private)
CNP P5
private)
McKinley
Avenue PS
McKinley
Intertie
SSI PS
private)
Notes:
a) The Stonebridge PS receives wastewater from four private pump stations: Panattoni, Gordon Trucking, Boise Cascade, and Utility Trailer. These pump stations convey wastewater collected by the private North Harlan Gravity System, which serves industrial parcels north of Brookfield Street.
Sewershed Lecend
North Harlan PS Monitoring Location ( Figure 2)
Stonebridge LS Monitoring Location ( Figure 3)
Woodfield LS Monitoring Location ( Figure 4)
O St SSMH Monitoring Location ( Figure 5)
O St PS Monitoring Location ( Figure 6)
McKinley Ave PS Monitoring Location ( Figure 7)
Schematic of Flow Monitoring Approach
e
environment
water
City of Lathrop
Lathrop, CA
December 2022
EKI C20049. 02
Figure 8
Figure 9:
Flow Data from 0 Street Sanitary Sewer Manhole - October 3 to 9
0. 1200
0. 1000
0.800
0.600
0 iL
0.400
0.200
0.000
liii441
O
O
Date
0 0O
1-
0 N
Co
OI
O
N
0 O
10/ 3/ 2022( Mon) 10/ 4/ 2022( 1' ue) 10/ 5/ 2022( Wed) 10/ 6/ 2022( 1hu) 10/ 7/ 2022( 1-n)10/ 8/ 2022( Sat) 10/ 9/ 2022( Sun) Maximum 0.00 0.79 0.67 0.65 0.89 0.79 0.86
Average 0.00 0.21 0.34 0.31 0.38 0.40 0.38
Minimum 0.00 0.00 0.09 0.04 0.04 0.09 0.07
Figure 10:
Flow Data from O Street Sanitary Sewer Manhole - October 10 to 16
0. 1200
0. 1000
0.800
0.600
0 LL
0.400
0.200
0.000
0 0
CV
0 ti
0 IN
IN
N
0 N
CV
O
f -I
0 ti
M
0 Date
IN
O
0 10/ 2022( Mon)10/1/ 2022( rue) 10/2/ 2022( Wed) 10/3/ 2022( 1 hu) 10/4/ 2022( rri)10/5/ 2022( Sat) 10/6/ 2022( Sun) Maximum 0.85 0.76 0.80 0.86 0. 107 0.99 0.89
Average 0.38 0.40 0.40 0.41 0.40 0.43 0.41
Minimum 0.06 0.02 0.06 0.10 0.11 0.10 0.10
Figure 11:
Flow Data from 0 Street Sanitary Sewer Manhole - October 17 to 23
0. 1200
0. 1000
0.800
0.600
LL
0.400
0.200
0.000
IN INI IN
IN CV IN
IN
IN
N
N
O
00 O
ti
O11
I
O
O
N
O
ti
Date
O
ti
N
N
O
N
M
N
O
10/// 2022( Mon) 10/8/ 2022( Tue) 10/9/ 2022( Wed) 10/ 20/ 2022( 1 hu) 10/ 21/ 2022( Fri) 10/ 22/ 2022( Sat)10/ 23/ 2022( Sun) Maximum 0.82 0.77 0.85 0.89 0.78 0. 119 0.93
Average 0.44 0.41 0.41 0.42 0.42 0.53 0.46
Minimum 0.12 0.08 0.09 0.05 0.07 0.12 0.11
N
R
N
O
Figure 12:
Flow Data from O Street Sanitary Sewer Manhole - October 24 to 30
0. 1200
0. 1000
0.800
0 0.600
0 LL
0.400
0.200
0.000
N
0 N
W
CV
ti
N
0 N
O
N
O
N
N
0 N
O
N
N
0 Date
N
0 CPI
0O
a - I
N
O
N
0 0
ti
10/ 24/ 2022( Mon) 10/ 25/ 2022( 1ue) 10/ 26/ 2022( Wed) 10/ 27/ 2022( 1hu) 10/ 28/ 2022( 1-n)10/ 29/ 2022( Sat)10/ 30/ 2022( Sun) Maximum 0. 110 0.93 0.89 0.92 0.84 0.95 0.93
Average 0.41 0.43 0.45 0.44 0.43 0.44 0.45
Minimum 0.12 0.08 0.10 0.08 0.07 0.06 0.08
N
O
N
m
O
Figure 13:
Flow Data from 0 Street Sanitary Sewer Manhole - October 31
0. 1200
0. 1
0. 1000
0.800
c
w
E 0.600 -
3 0
U.
0.400 -
0.200
0.000
N
N
0 N
0 1-4
0. 2
0. 3
0. 4
0. 5
0. 6
0. 7
0. 8
0. 9
Date
10/ 31/ 2022( Mon)
Maximum 0.91
Average 0.45
Minimum 0.12
Appendix D
Recommended CIP Details
APPENDIX D
Recommended CIP Details
eki environment
water
ELti
U
a
I
I
I
I
I
I
I
I
I
I
I
1 I
I
e /
r
1 t
t
t
r8"
PVC
1 U
1/4
1 I
d
g
4,,
L. 1-„... 8", PVC it
8' PVC •
8" PVC• , •
U
a
8" PVC
Stonebridge
PS
fU
8„ VCP 0 8„ VCP • • •
6" VCP "'
8 VCP < > >
g.. V• CP • • • • •° • 8„ VCP • •
a 8" VCP• •
p
vc• • •
Legend
PS
8" PVC
Sphere of Influence
Existing Gravity Main
Existing Force Main
Lift Station
Manhole
Inch -Diameter and Pipe Material
Abbreviations
PVC = polyvinyl chloride
VCP = vitrified clay
Notes
1. All locations are approximate.
Replacement Gravity Main
8"
OEM 10"
12"
15"
18"
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, obtained 9 January 2018.
Parallel Force Main
6"
0 500 1, 000
Feet
eki
Stonebridge Gravity Main
Replacement and Parallel
Force Main Project
Wastewater System Master Plan
City of Lathrop
December 2024
environment EKI C20049. 02
water Figure D- 1
FigE tewater\
WoodfieldWestCIP. m2
a8th:
660038\ Maps 2018\ 1Delivers X:\
1 tea
8" PVC
8" VCP •
P,
6" VCPT
8VCP •
PVC
K,. PVC 4
Valley 1'
Crossings LS
VCP'
O)
f<
i° • •
VCP.
CL
U
0`
S.
VCP
Legend
IaU
8" VCP
8" VCP •
8" VCP
VCP
8" VCP •
0 VCP oo • 0-•
8' VCP
8" VCP
8" VCP
co
8"vcP• •
a
VCP
vC; •
8" PVC
Sphere of Influence
Existing Gravity Main
Existing Force Main
Lift Station
Manhole
Inch - Diameter and Pipe Material
Abbreviations
PVC = polyvinyl chloride
VCP = vitrified clay
Notes
1. All locations are approximate.
III Lift Station Upgrade
Replacement Gravity Main
8"
fi 10"
12"
EMI 15"
18"
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, obtained 9 January 2018.
0 500 1, 000
Feet
Woodfield West Deficiency
Project - Alternative A
Wastewater System Master Plan
City of Lathrop
December 2024
e1( 1
environment EKI C20049. 02
water Figure D- 2
M
aps\ 2018\ 1 \
Delivers
x
8" PVC
RIF IN II IIIII II
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IV
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Valley Crossings LS
CLIID
6" VCP• •
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U
05 Woodfield
LS
a 8" VCP
U
r`
c • • 8• VCP•
o i s 8' CP_
P • ••
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S.
6. VCp-•---
I' •
S.
Legend
if I
L1
Nommm
Sphere of Influence
Existing Gravity Main
Existing Force Main
Lift Station
Manhole
Inch - Diameter and Pipe Material
Abbreviations
PVC = polyvinyl chloride
VCP = vitrified clay
Notes
1. All locations are approximate.
MI Lift Station Upgrade
Parallel I New Force Main
6"
8"
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, obtained 9 January 2018.
0 1, 000 2, 000
Feet
Woodfield West Deficiency
Project - Alternative B
Wastewater System Master Plan
City of Lathrop
December 2024
e1( 1
environment EKI C20049. 02
water Figure D- 3
M
ap
s\2018\
1 \
Delivers
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8"VCP•
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6"VCP•
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Crossings LS •
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U
co
6" VCP
6" VCP 6" VCP
o_
U
6" VCP
El Mg MN MI
PS
MCP
Sphere of Influence
Existing Gravity Main
Existing Force Main
Lift Station
Manhole
8" PVC Inch - Diameter and Pipe Material
Abbreviations
PVC = polyvinyl chloride
VCP = vitrified clay
Notes
1. All locations are approximate.
8" VCP•• 8" VCP
CQ •
o C
CO. ° O•
o
so
8" VCP •
8" VCP• •
o
o
8V
C P •° o • •
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8" VCP • a
co o
n 8VCP• • • 0•
Elm
U
co
Legend
qs
Woodfield / ________________________________
a.
U
Replacement Gravity Main
8"
10"
12"
15"
18"
Sources
1. Aerial photograph provided by ESRI' sArcGIS Online, obtained 9 January 2018.
6" VCP
0 California
Natural Products
PNPrivate)
500 1, 000
Scale in Feet)
Woodfield East Gravity
Main Replacement Project
Wastewater System Master Plan
City of Lathrop
December 2024
eI< i
environment EKI& water Figure D- 4
a
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8" PVC
Sphere of Influence
Existing Gravity Main
Existing Force Main
Lift Station
Manhole
Inch -Diameter and Pipe Material
Abbreviations
PVC = polyvinyl chloride
VCP = vitrified clay
Notes
1. All locations are approximate.
Replacement Gravity Main
8"
10"
12"
15"
18"
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, obtained 9 January 2018.
0 500 1, 000
Scale in Feet)
Easy Court/ 0Street Gravity
Main Replacement Project
Wastewater System Master Plan
City of Lathrop
December 2024
e1( 1
environment EKI C20049. 02
water Figure D- 5
ATTACHMENT E
eki environment
water
2025 RECYCLED WATER SYSTEM MASTER
PLAN AMENDMENT
City of Lathrop
Lathrop, California
May 2025
EKI C20049. 03
EKI ENVIRONMENT & WATER, INC. 2001
www. ekiconsult. com
Junipero Serra Blvd, Suite 300 • Daly City, CA 94014
eki environment
water
2025 Recycled Water System Master Plan Amendment
City of Lathrop
May 2025
Prepared for:
City of Lathrop
390 Towne Centre Drive
Lathrop, CA 95330
Prepared by:
EKI Environment & Water, Inc.
2001 Junipero Serra Blvd., Suite 300
Daly City, California 94014
650) 292- 9100
www. ekiconsult. com
EKI C20049. 03
41-
Jonathan Sutter, P. E.
Project Manager/ Supervising Engineer
FiK, k (A)
an
Tina Wang, P. E.
Assistant Project Manager/ Associate Engineer
Yuqing Gao, EIT
Staff Engineer
2025 Recycled Water System Master Plan Amendment
City of Lathrop
TABLE OF CONTENTS
EXECUTIVE SUMMARY ES -1
TABLE OF CONTENTS I
TABLES ( IN REPORT TEXT) II
FIGURES ( IN REPORT TEXT) III
APPENDICES III
ABBREVIATIONS AND ACRONYMS IV
EXECUTIVE SUMMARY 1
1 INTRODUCTION 1-
1. Project Background 1-
1. 2 Scope of Work 1-
1. 3 Report Organization 1-2
2 STUDY AND SERVICE AREA 2-1
2. 1 City Limits, Sphere of Influence, and Service Boundaries 2-1
2. Current and Projected Recycled Water Use Areas 2-1
3 RECYCLED WATER INFRASTRUCTURE 3-1
4 RECYCLED WATER SUPPLY, DEMAND, AND WATER BALANCE EVALUATION 4-1
4. 1 Recycled Water Supply 4-1
4. 2 Recycled Water Demand 4-1
4. 2. 1 Current and Historical Recycled Water Demand 4-1
4.2. Projected Recycled Water Demand 4-1
4. 3 Recycled Water Balance Evaluation 4-3
4.3. 1 Recycled Water Use Balance Scenarios 4-3
4.3. 2 Recycled Water Balance Methodology 4-3
4.3. Recycled Water Balance Results 4-
5 RECYCLED WATER SYSTEM OPERATION STRATEGY 5-1
5. 1 Recommended Recycled Water System Layout 5-1
5. 2 Pressure Zones 5-2
5. 3 Improving Recycled Water Quality 5-2
6 SYSTEM PERFORMANCE AND DESIGN CRITERIA 6-1
6. 1 Distribution System Performance Criteria 6- 1
6. 1. Peaking Factors 6- 1
6. 1. 2 Distribution System Pressures 6- 2
6. 2 Recycled Water System Facilities 6- 2
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6. 2. 1 Recycled Water Transmission and Distribution Pipeline Sizing Criteria 6-2
6. 2. Velocity Criteria 6- 3
6. 2. 3 Head Loss Criteria 6- 3
6. 2. 4 Booster Pump Stations 6-3
7 DISTRIBUTION SYSTEM HYDRAULIC ASSESSMENT 7-1
7. 1 Hydraulic Modeling Approach 7-1
7. 2 Hydraulic Model Update 7-1
7.2. 1 Model Platform 7- 1
7. 2. Model Construction 7-1
7. 2.3 Model Validation 7-2
7. 3 Modeling Scenarios 7-2
7. 4 Recycled Water Distribution System Hydraulic Evaluation 7-3
7. 4. 1 Near -term Scenario Evaluation 7-3
7. 4. 2 Buildout Scenario Evaluation 7-
8 RECOMMENDED CAPITAL IMPROVEMENT PROGRAM 8-1
8. 1 Pump Station PMP- 1 Upgrade 8-4
8. 2 Pump Station PMP- 10 Upgrade 8-4
8. 3 Treatment at Storage Ponds S5 and S16 8-5
8. 4 River Islands Phase 2 Backbone Main Improvement 8-5
8. 5 Pressure Reducing Valve Station Improvement 8-6
8. 6 Conversion of Potable Irrigation Areas to Recycled Water 8-7
8. 7 Recycled Water Metering and Billing Improvements 8-
8. Recycled Water Operations and Permitting 8-
9 REFERENCES 9-1
TABLES ( IN REPORT TEXT)
Table 2-1. Existing Recycled Water Landscape Irrigation Area by Development Area 2-3 Table 2-. Cumulative Recycled Water Use Area by Development Area 2- 5 Table 4-1. Projected Recycled Water Supply 4-1
Table 4-2. Current and Historical Recycled Water Use 4- 1 Table 4-3. Projected Average Annual and Maximum Month Recycled Water Demand 4-2 Table 4-. Projected Average Annual Recycled Water Demand by Development Area 4-2 Table 4-5. Summary of Required Recycled Water Storage and Use Areas 4-5 Table 5-1. Existing Storage Pond Characteristics 5- 1
Table 6-1. Peak Recycled Water Demand at Buildout 6- 1
Table 6-2. Summary of Recommended Recycled Water System Performance and Operation Criteria 6-4 Table 7-1. Modeled Recycled Water Demands 7-2
Table 8-1. Summary of Recommended Recycled Water System Capital Improvement Projects 8-2 Table 8-2. Project RW- 1 Details and OPCs 8-4
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Table 8-3. Project RW- 2 Details and OPCs 8-5
Table 8-4. Project RW- 4 Details and OPCs 8-6
Table 8-5. Project RW- 5 Details and OPCs 8-7
FIGURES ( IN REPORT TEXT)
Figure 2-1. City of Lathrop Boundaries and Development Areas 2- Figure 2-. Recycled Water Landscape Irrigation Areas 2-6 Figure 3-1. Recycled Water Infrastructure to be Decommissioned 3- 2 Figure 3-2. Existing Recycled Water System Infrastructure 3- Figure 4-1. Projected Average Annual Recycled Water Demand by Development Area 4-3 Figure 4-2. Water Balance Monthly Flow Summary in 2030 4-6 Figure 4-3. Water Balance Monthly Flow Summary at 2045 ( Buildout) 4-7 Figure 5-1. Recommended Buildout Recycled Water System 5-3 Figure 7-1. Near -term Recycled Water System Hydraulic Evaluation — System Pressure during PHD 7-4 Figure 7-2. Near -term Recycled Water System Hydraulic Evaluation — Pipe Velocity during PHD 7-5 Figure 7-3. Near -term Recycled Water System Hydraulic Evaluation — Pipe Head Toss during PHD 7-6 Figure 7-4. Buildout Recycled Water System Hydraulic Evaluation — System Pressure during PHD 7-8 Figure 7-5. Buildout Recycled Water System Hydraulic Evaluation — Pipe Velocity during PHD 7-9 Figure 7-6. Buildout Recycled Water System Hydraulic Evaluation — Pipe Head loss during PHD 7- 10 Figure 8-1. Recommended Recycled Water System Improvements 8-3
APPENDICES
Appendix A Water Balance Calculations
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ABBREVIATIONS AND ACRONYMS
A# WDR permitted land application area number
AAFES Army & Air Force Exchange Services
ac acre
ACE Altamont Commuter Express
ADD Average Daily Demand
ADWF average dry weather flow
AFY acre- feet per year
AOI Area of Interest
AWWA American Water Works Association
BPS booster pump station
CCI Construction Cost Index
CEQA California Environmental Quality Act
CI' commercial, industrial, and institutional
CIMIS California Irrigation Management Information System CIP capital improvement projects
City City of Lathrop
CLSP Central Lathrop Specific Plan
CTF Consolidated Treatment Facility
d/ D depth to diameter
Depot Sharpe Army Depot
DOF Department of Finance
EKI EKI Environment & Water, Inc.
ENR Engineering News Record
fps feet per second
ft feet
GIS geographical information system
gpd gallons per day
gpm gallons per minute
GW groundwater
I-5 Interstate 5
Kft kilofoot
IWRMP Integrated Water Resources Master Plan
Lathrop CTF Lathrop Consolidated Treatment Facility
LAA land application area
LF linear feet
LI landscape irrigation
LS lump sum
MDD Maximum Day Demands
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2025 RWSMP Amendment
City of Lathrop
MG million gallons
MGD million gallons per day
MMD maximum month demands
MWQCF Manteca Wastewater Quality Control Facility
NPDES National Pollution Discharge Elimination System
OPC Opinion of Probable Construction Cost
PHD peak hour demands
PMP Pump
PS Pump Station
psi pounds per square inch
PVC polyvinyl chloride
RWSMP Recycled Water System Master Plan
RWQCB Regional Water Quality Control Board
S# WDR permitted recycled water storage pond number
SCADA Supervisory Control and Data Acquisition
SOI Sphere of Influence
SWRCB California State Water Resources Control Board
VFD variable frequency drive
WDR Waste Discharge Requirement
WWSMP Wastewater System Master Plan
WWTF wastewater treatment facility
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EKI C20049. 03
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Executive Summary City of Lathrop
EXECUTIVE SUMMARY
EKI Environment & Water, Inc. ( EKI) has prepared this Recycled Water System Master Plan ( RWSMP) Amendment for the City of Lathrop, California ( City). This RWSMP was developed as part of the 2024-5 amendment to the City' s Integrated Water Resources Master Plan ( IWRMP Amendment), a comprehensive planning process involving the City' s
Potable Water System, Wastewater System, and
Recycled Water System Master Plans. This RWSMP incorporates new information that has become available and changed planning assumptions since the completion of the 2019 RWSMP ( EKI, 2019c) and EKI' s 2020 technical memorandum: CTF Effluent Discharge and Recycled Water Systems Operations ( EKI, 2020).
STUDY AND SERVICE AREAS
The City of Lathrop is located in San Joaquin County, approximately 10 miles south of the City of Stockton and directly west of the City of Manteca. The City lies east of the Coastal Range that separates California' s Central Valley from the San Francisco Bay Area. Interstate 5 ( I-5), a major north -south interstate corridor, bisects the City. The community was originally developed primarily east of I-5. However, most major new developments have been constructed west of I-5 and others are currently planned or under construction in this area.
The City is currently providing recycled water to 54. 7 acres of landscape irrigation ( LI) areas located primarily in the Central Lathrop and Mossdale development areas. Projected future uses of recycled water will continue to consist of landscape irrigation to a total of 657. 4acres by buildout ( 2045). This estimate includes the non -potable irrigation demand at River Islands, which is currently supplying its non -potable demand with its own non -potable water ( NPW) system and plans to use recycled water from the City in the future.
CITY' SEXISTING RECYCLED WATER INFRASTRUCTURE
The City' srecycled water system was originally built to support the disposal of the effluent produced by the City -owned Lathrop Consolidated Treatment Facility ( CTF) via agricultural land application areas LAAs) and use of recycled water for urban landscape irrigation ( LI). The land use required for LAAs and the necessary seasonal storage ponds limit the potential development areas within the City. Thus, the City obtained a National Pollutant Discharge Elimination System ( NPDES) permit 2021 to discharge effluent to the San Joaquin River to eliminate the need for LAAs and large storage ponds. The City has been discharging CTF effluent to the San Joaquin River since February 2024 and has decommissioned LAAs and the majority of its storage ponds and pump stations to optimize the system for a smaller amount of recycled water demands associated with urban landscape irrigation. Figure ES - 1 shows the locations of the City' s existing recycled water system facilities.
RECYCLED WATER SUPPLY AND DEMAND EVALUATION
As estimated in the City' s 2024 Wastewater System Master Plan Amendment ( EKI, 2024a), future Lathrop CTF expansions are projected to produce up to 4. 31 million gallons per day ( MGD) of tertiary treated effluent suitable for landscape irrigation at buildout. Current effluent or recycled water production at the Lathrop CTF is 1. 06 MGD in 2022.
The City provided a total of 194 acre- feet of recycled water to LI areas in 2022. By its buildout in 2045, the City anticipates a total annual recycled water demand of 2. 4 MGD or 2, 688 acre- feet per year ( AFY), which is a significant reduction from demands estimated in prior planning documents due to river discharge of effluent.
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Executive Summary City of Lathrop
EKI conducted water balance evaluations to estimate the projected recycled water demand and seasonal storage requirements. The recycled water balance was conducted for the near -term (2030) and buildout 2045) scenarios based on projected flows to the Lathrop CTF and LI acreage. The required seasonal storage is estimated to be 61. 4 million gallons ( MG) by 2030 and 71. 5 MG by 2045, which can be met by existing ponds S5 and S16 with a total capacity of 129. 5 MG.
RECYCLED WATER SYSTEM OPERATION STRATEGY AND DESIGN
Pump stations PMP- 1 and PMP- 10 will need to be upgraded to expand their capacities to supply peak recycled water demands and continually pressurize the recycled water system. To optimize its recycled water system, it is recommended that the City install pressure reducing valve stations to create two pressure zones, one for River Islands and one for the rest of the City. In addition, new transmission mains are recommended to improve distribution system capacity and support new development.
Due to algae growth in the storage ponds, which has resulted in maintenance issues with the irrigation systems, the City is exploring options to add filtration or other treatment to the recycled water pumped out of the storage ponds. Additionally, given that only a portion of the existing capacity of ponds S5 and S16 are needed to meet peak seasonal demands, the City could elect to reduce the capacity and/ or partition the ponds into smaller cells to lower maintenance requirements and improve recycled water quality.
HYDRAULIC ASSESSMENT
EKI updated the recycled water system hydraulic model to assess the recommended optimizations in the near -term and at buildout. Modeling results verify that design criteria are met throughout the system under peak hour demand conditions with the recommended optimizations.
RECOMMENDED CAPITAL IMPROVEMENT PROGRAM
Recommended CIPs were developed to support the City' srecycled water system operation strategy and include the improvements required to optimize the system with river discharge. EKI' s proposed CIPs are recommended in addition to the recycled water system CIPs listed in the City' s Capital Improvement Program, Fiscal Year 2023 — 2025 ( Lathrop, 2023). Table ES -1 summarizes the identified CIPs and their estimated planning level opinion of probable costs ( 0PCs). Figure ES -2 shows the recycled water system at buildout with the proposed improvements and optimizations. kienvironment water ES -2
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EKI C20049. 03
Executive Summary
2025 RWSMP Amendment
City of Lathrop
Table ES - 1. Summary of Recommended Recycled Water System Capital Improvement Projects Project # Improvement Description OPC ( a)
City Projects
RW- 1 Pump Station PMP- 1 Upgrade 6, 060,00
RW- 2 Pump Station PMP- 10 Upgrade 10,20, 000
RW- 3 Treatment at Storage Ponds 55 and S16 1, 547, 000 (b) RW- 6 Conversion of Potable Irrigation Areas to Recycled Water TBD ( c) RW- 7 Recycled Water Metering and Billing Improvements TBD ( c) RW- 8 Recycled Water Operations and Permitting (City RW 23- 02) 69, 915 (d) Total City CIP OPC 17, 797, 000
Developer Funded Projects
RW- 4 River Islands Phase 2 Backbone Main Improvement 17, 880, 000 RW- 5 Pressure Reducing Valve Station Improvement 860, 00 Abbreviations:
CIP = capital improvement projects OPC = Opinion of Probable Construction Cost Notes:
a) Detailed costs for RW- 1, RW- 2, RW- 4 and RW- 5are estimated in following sections and are presented in December 2024 dollars.
b) Costs for RW- 3are based on estimates provided by City staff on 7 February 2025. c) Projects RW- 6and RW- 7 are recommended to be further refined in the near future. d) Costs for RW- 8 was carried over from the City' s Capital Improvement Programs Fiscal Years 2023 - 2025 ( Lathrop, 2023).
e) Total may not sum due to rounding.
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EKI C20049. 03
ems.•'./•'.
l
neaaeIaad
RI. PS
PMP
Legend 7 Sphere of Influence
Existing Pipe Diameter, Inches
6 - 16 8 20
10 - 24
12 Recycled Water Distribution Infrastructure
Storage Pond
Percolation Basin
Land Application Area
Landscape Irrigation Area
Existing Pump Station
Abbreviations
RI - PS = River Islands Pump Station
SOI = Sphere of Influence
RW = Recycled Water
Notes
1. All locations are approximate.
2. The River Islands Pump Station ( RI - PS) pumps to the independent River Islands non - potable water
system ( not shown).
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, 8 May 2025. N o 4, 000 S000 Soak In Feet)
Existing Recycled Water System
Recycled Water System Master Plan Amendment
City of Lathrop
Lathrop, CA
May 2025
Q environment C2004903
G & water Figure ES -
1 RW- 5: Pressure Reducing Valve
Station Improvement
RW- 4: River Islands Phase 2
Backbone Main Improvement
RW- 2: PMP- 10
Upgrades
RW- 1: PMP- l/
Upgra% s••
DRV- 2
RWJ: Trea - nt at
Ponds S5 and Sib
515 `
I." •
T
1 1
1 1
Legend
L Sphere of Influence
Future Pipe Diameter, Inches
6 20
Recycled Water Distribution Infrastructure
Mfg Landscape Irrigation Area
El City Pump Station
Discharge to RI Non -Potable Water System
Storage Pond
Existing Pipe
Pressure Reducing VaNe Station
Abbreviations
LAA = land application area
RI = River Islands
RW = Recycled Water
SOI = Sphere of Influence
Notes
1. All locations are approximate.
2. Existing storage ponds, mains, and pump stations storing or conveying treated water to LAAs are assumed to be
abandoned at buildout.
Sources
1. Aerial photograph provided by ESRI' sArcGIS Online,
5 May 2025.
N
o 4, 000 8, 000
A ( Scale in Feet)
Recommended Recycled Water
System Improvements
Recycled Water System Master Plan Amendment
cay of Lathrop
Lathrop, CA
ekienvironment May 202520049.03
water Figure ES -2
Section 1
Introduction
2025 RWSMP Amendment
City of Lathrop
1 INTRODUCTION
EKI Environment & Water, Inc. (EKI) has prepared this Recycled Water System Master Plan ( RWSMP) Amendment for the City of Lathrop, California ( City). This RWSMP was developed as part of the 2024-5 amendment to the City' s Integrated Water Resources Master Plan ( IWRMP Amendment), a comprehensive planning process involving the City' s
Potable Water System, Wastewater System, and
Recycled Water System Master Plans. This RWSMP updates the City' s 2019 RWSMP ( EKI, 2019a). The IWRMP Amendment was completed through a coordinated effort between multiple City departments and provides a unifying framework to support utility operations and Capital Improvement Project ( CIP) development and implementation.
1. Project Background
The City' s 2019 IWRMP, which includes the City' s Water System Master Plan, Wastewater System Master Plan, and Recycled Water System Master Plan, was finalized and approved by the City Council in December 2019 after a California Environmental Quality Act ( CEQA) process ( EKI, 2019a; 2019b; 2019c). Since the IWRMP was completed, new information has become available and certain planning assumptions have changed that require an amendment to the IWRMP, including the following related to the recycled water system:
Land Use Information: The City completed a General Plan Update in September 2022 which included updated growth projections for the City. In addition, development projections have changed significantly in the River Islands area with approval of the modified River Islands Phase 2 project in June 2021 and in the Central Lathrop area.
River Discharge Permit: The City has obtained a National Pollutant Discharge Elimination System NPDES) permit to dispose a portion of the wastewater treated at the Lathrop Consolidated Treatment Facility ( CTF) in the San Joaquin River, with the remaining portioned delivered as recycled water to City owned parks and landscaping as well as retail customers. To support use of recycled water for landscape irrigation, the City obtained coverage under General Order WQ2016- 0068- DDW issued by State Water Resources Control Board ( SWRCB) (SWRCB, 2016) and submitted a Title 22 Report Addendum in 2020. The City began delivering recycled water for urban uses in the summer of 2021. These changes reduce the City' s potable water demand, and affect the operations and infrastructure needed of the City' s wastewater effluent disposal and recycled water distribution systems.
Due to the implementation of river discharge of wastewater effluent, the projected water recycled water demand at buildout is estimated to be significantly smaller compared to projections from prior planning documents. This RWSMP provides updated analyses and conclusions including updated water demand, updated water balance evaluations, and associated CIPs.
1. 2 Scope of Work
The scope of work for the RWSMP included the following primary tasks:
Update of the recycled water system hydraulic model network to incorporate system improvements completed since the 2019 RWSMP;
Inclusion of backbone infrastructure in the future recycled water system hydraulic model network based on recent utility plans completed by City or Developers ( e.g., the Land Park at Lathrop Backbone Infrastructure Plans);
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EKI C20049. 03
Section 1
Introduction
2025 RWSMP Amendment
City of Lathrop
Delineation of existing recycled water urban landscape irrigation areas in the City based on landscape plans completed by the City and satellite images; Evaluation of City' s future uses of recycled water and development of recycled water demand projections;
Review of the City' s basic assumptions, criteria, and conclusions in recycled water planning, e.g., recycled water system design criteria, recycled water balance analyses, and pump station operations;
Development of recommended recycled water system operation strategy with river discharge; Verification of the recommended strategy under future demand conditions using steady- state model simulations;
Development of a recommended recycled water system improvements; and Preparation of the amended RWSMP document.
1. 3 Report Organization
The RWSMP is organized into the following sections:
Section 1— Introduction
Section 2 — Study and Service Area
Section 3 — Recycled Water Infrastructure
Section 4 — Recycled Water Supply, Demand, and Water Balance Evaluation Section 5 — Recycled Water System Operation Strategy
Section 6 — System Performance and Design Criteria
Section 7 — Distribution System Hydraulic Assessment
Section 8 — Recommended Capital Improvement Program
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EKI C20049. 03
Section 2 2025 RWSMP Amendment
Study and Service Area City of Lathrop
2 STUDY AND SERVICE AREA
The City of Lathrop (also referred to herein as the City) was incorporated on July 1, 1989, and is located in San Joaquin County, approximately 10 miles south of the City of Stockton and directly west of the City of Manteca. The City lies east of the Coastal Range that separates California' sCentral Valley from the San Francisco Bay Area. Interstate 5 ( I-5), a major north -south interstate corridor, bisects the City. The City is also connected by Highway 120 which runs east -west through the southeastern - most part of the City, and by Interstate 205, which connects Interstate 580 to I-5. The City is also served by the Altamont Commuter Express ( ACE) train, which travels along the southern and eastern border of the City. The community was originally developed primarily east of I-5. Beginning in 2003, major new developments have been constructed west of I-5 and others are currently planned or under construction in this area.
2. 1 City Limits, Sphere of Influence, and Service Boundaries The City currently encompasses an area of approximately 13, 400 acres, or about 20. 9 square miles, however its Sphere of Influence ( SOI) is slightly larger with an area of about 13, 600 acres, or 21. square miles. The City' s
SOI includes two unincorporated areas:
1. Approximately 134 acres northeast of the City boundary and along Roth Road that is designated Freeway Commercial and Light Industrial, and
2. Approximately 62 acres southeast of the City boundary that is pre -zoned for industrial uses and part of the Lathrop Gateway Business Park Specific Plan area.
The City reduced their SOI in 2016 to exclude an additional unincorporated area ( approximately 2, 100 acres) located north of the Central Lathrop Specific Plan ( Central Lathrop or CLSP) area and west of I-5.
Much of this area does not have a General Plan land use designation. The City has designated this area as an Area of Interest (AOI) (Lathrop, 2016). Figure 2- 1 shows the City limits, SOI, and AOI.
The City has experienced significant growth in recent years and is anticipating growth to continue, particularly in several approved or pending large development projects within the City. Boundaries of the City' s major development areas are shown on Figure 2-1.
The City' srecycled water distribution system is within the City limits. The City provides recycled water to city -owned parks and landscape areas primarily in the Central Lathrop and Mossdale Landing development areas beginning in 2021. In addition, the City applied recycled water to land application areas ( LAA) as a means to dispose of effluent produced at the Lathrop CTF until February 2024, when the City began implementing river discharge of the effluent. The City' s recycled water system is further discussed in Section 3.
2. Current and Projected Recycled Water Use Areas
The City is currently providing recycled water to 54. 7 acres of landscape irrigation ( LI) areas located in the Central Lathrop, Mossdale, River Islands, and Lathrop Gateway areas. An additional 22. 4 acres of LI areas are connected to the recycled water system but currently receive potable water. The City plans to convert these areas to receive recycled water in the near future. A list of the existing LI areas and their statuses is provided in Table 2-1. The LI areas are geographically shown on Figure 2-A through Figure 2-D. eki environment
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EKI C20049. 03
Legend
L_j
City Limit
Sphere of Influence
Area of Interest
Rail Cargo Container Yard
Development Areas
Central Lathrop
QCrossroads
p
Historic Lathrop Infill and Other Developments
Lathrop Gateway
Mossdale Landing
Mossdale Landing West
Mossdale Landing East
Mossdale Landing South
MRiver Islands
Sharpe Army Depot
South Lathrop
Notes
1. Al locations are approximate.
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, 5 May 2025.
0 4, 000 8 000
Scale m Feet;
eki
City of Lathrop Boundaries
and Development Areas
Recycled Water System Master Flan Amendment
Coy or Lathrop
Lathrop, CA
May 2025
environment C20049, 03
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Section 2
Study and Service Area
2025 RWSMP Amendment
City of Lathrop
Table 2-1. Existing Recycled Water Landscape Irrigation Area by Development Area Site ID ( a)
Assessor' sParcel Currently Served by Irrigated Area
Number Recycled Water? ( Acres) (b)
Central Lathrop
CLSP- 1 19203046 0. 25
CLSP- 2 19224002 1 0. 32
CLSP- 3 19204022 1 0. 47
CLSP- 4 19213057 J 1. 07
CLSP- 5 19218080 1 0. 70
CLSP- 6 19215021 0. 92
CLSP- 7 19210090 1 1. 95
CLSP- 8 19203026 1 1.6
CLSP- 9 19206014 1. 47
CLSP- 10 19219071 1. 06
CLSP- 11 19203029 0. 57
CLSP- 12 19211063 1 4. 75
CLSP- 13 19203051 1.2
CLSP- 14 19220065 0. 82
CLSP- 15 19227032 0. 79
CLSP- 16 19204020 2. 01
River Park North 19203054 4. 55
Leland and Jane Stanford Park 19203036 7. 46
Subtotal Central Lathrop LI Area Receiving Recycled Water 18. 9 Subtotal Existing Central Lathrop LI Area 31. 5
Mossdale
M- 1 24102072 0. 25
M- 2 19136068 0. 90
M- 3 19139069 1. 27
M- 4 19119034 1. 61
M- 5 24170027 1 1. 09
M- 6 19135004 1 4. 11
M- 7 19135004 2. 02
M- 8 19133009 5. 80
M- 9 19133010 1. 64
M- 10 19138067 1.9
M- 11 19154011 1. 09
M- 12 24170028 3. 59
M- 13 19137025 4. 13
M- 14 19154001 J 1. 35
M- 15 19145018 1 0. 30
M- 16 19144007 1 0. 31
M- 22 19176020 1 1. 32
M- 23 19157005 0. 34
M- 24 19160056 1. 39 J
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Section 2
Study and Service Area
2025 RWSMP Amendment
City of Lathrop
Table 2-1. Existing Recycled Water Landscape Irrigation Area by Development Area ( Continued) M- 25
Site ID ( a)
Assessor' sParcel
Number
19152030
Currently Served by
Recycled Water?
Irrigated Area
Acres) (b)
1. 03
M- 26 19158019 0. 50
M- 27 19155062 0. 24
M- 28 19151001 0. 53
M- 29 19139022 0. 42
M- 30 19119056 0. 95
M- 31 19134019 0. 63
M- 32 19147008 0. 98
M- 33 19158037 0.8
M- 34 19136011 0. 35
M- 35 19166034 0. 38
M- 36 24171005 0. 43
M- 37 19162029 0. 46
M- 38 19163038 0. 48
M- 39 19170007 0. 15
M- 40 24102060 0. 20
M- 41 19119048 1.9
Subtotal Mossdale LI Area Receiving Recycled Water 35. 2 Subtotal Existing Mossdale LI Area 44. 9
Other
CTF- 1 19813036 0. 37
GW- 1 24139015 0. 14
GW- 2 24182003 0. 11
RI - 1 19162058 0. 11
Subtotal Other LI Area Receiving Recycled Water 0. 62
Subtotal Existing Other LI Area 0. 73
TOTAL LI AREA RECEIVING RECYCLED WATER 54. 7
TOTAL EXISTING LI AREA 77. 1
Notes:
a) Existing recycled water use areas based on the CalSense meter report provided by City on March 27, 2023.
b) Areas delineated based on satellite map and associated landscape plans provided by City. eki environment
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May 2025
EKI C20049. 03
Section 2
Study and Service Area
2025 RWSMP Amendment
City of Lathrop
Future uses of recycled water will consist of expanded landscape irrigation. New LI areas are anticipated in the River Islands, Central Lathrop, and Mossdale Landing areas as these development areas continue to be built out. The River Islands area currently operates its own non -potable water system to meet non - potable landscape irrigation demand with San Joaquin River and lake water. The River Islands non -potable water system can also receive recycled water from the City. For the purposes of this document, it is assumed that River Islands plans to use the City' s recycled water to meet its non - potable irrigation demand beginning in 2025.
The projected acreage of recycled water use by development area is summarized in Table 2- in 5 -year increments through buildout ( 2045). The City anticipates a total of 657. 4 acres of LI areas by buildout, including 482. 6acres of LI areas within River Islands.
Table 2-. Cumulative Recycled Water Use Area by Development Area Development Area
Central Lathrop ( c)
Existing
2022)
18. 9
Total New Recycled Water Use Area (acres) (a)( b)
2025 2030 2035 2040
36. 0 75. 1 80. 1 109. 7
Buildout
2045)
109. 7
Mossdale 35. 2 44. 9 53. 64. 5 64. 5 64. 5
River Islands 0. 1 156. 4 265. 4 374. 5 482. 6 482. 6
Lathrop Gateway 0. 2 0. 2 0. 2 0. 2 0. 2 0. 2
Crossroads 0. 4 0. 4 0. 4 0. 4 0. 4 0. 4
TOTAL 54. 8 237. 9 394. 6 519. 7 657. 4 657. 4
Notes:
a) Future LI area acreages are estimated based on development plans provided by the City. b) Recycled water areas temporarily supplied by potable water are assumed to be connected to the recycled water system by 2025.
c) It assumed that 5% of the Central Lathrop Phase 2 development will be public landscape or park areas to be irrigated with recycled water.
eki environment
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May 2025
EKI C20049. 03
Legend
1 Sphere of Influence
Pipe
Pump Station
Existing Landscape Irrigation Area
Planned Future Landscape Irrigation Area
Abbreviations
RI - PS = River Islands Pump Station
5O1 = Sphere of Influence
RW = Recycled Water
Notes
1. All locations are approximate.
2. The River Islands Pump Stations ( RI - PS and RI Phase 2 PS) pumps to the independent River Islands non - potable water system ( not shown).
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, 5 May 2025.
800 1, 600
Scale inree0
Recycled Water Landscape Irrigation Areas
Recycled Water System Master Plan Amendment
City of Lathrop
Lathrop, CA
eki environment May 2025
cC20049. 03
Figure & water 2-A
zyoml
CLSP- 12
M- 15
er
M
M- 32
CLSP.- 1L
CLSP- 8
M28\
CLSP- 6
CLSP- 1g
CLSP- 5
CLSP- 15'
CLSP- 9
CLSP- 2f
CLSP- 3
M -2j
MC21M
24 M- 22 :.. :.:;
CLSP- 7__
Legend
Sphere of Influence
Pipe
Pump Station
Existing Landscape Irrigation Area
I Planned Future Landscape Irrigation Area
Abbreviations
RI - PS = River Islands Pump Station
SOI = Sphere of Influence
RW = Recycled Water
Notes
1. AlI locations are approximate.
2. The River Islands Pump Stations ( RI - PS and RI Phase 2 PS) pumps to the independent River Islands non - potable water system ( not shown).
Sources
I. Aerial photograph provided by ESRI' s ArcGIS Online, 5 May 2025.
800 1, 600
Scale
Landscape Irrigation Area
Recycled Water System Master Plan Amendment
City of Lathrop
Lathrop, CA
ski environment µ0y1025
49. 03
water re02- Figure 2-B26
Legend
L! Sphere of Influence
Pipe
J Pump Station
Existing Landscape hrigation Area
Planned Future Landscape Irrigation Area
Abbreviations
RI - PS = River Islands Pump Station
SOI = Sphere of Influence
RW = Recycled Water
Notes
1. All locations are approximate.
2. The River Islands Pump Stations ( RI -PS and RI Phase 2 PS) pumps to the independent River Islands non - potable water system ( not shown).
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, 5 May 2025.
0 800 1, 600
snob in Fee0
Recycled Water Landscape Irrigation Areas
Recycled Water System Master Plan Amendment
cry of Lathrop
Lathrop, CA
May 2025 ekenvironment C20049. 03 I & water Figure 2-C
Legend
C: 1,. Sphere of Influence
Pipe
Q Pump Station
Existing Landscape Irrigation Area
Planned Future Landscape Imgation Area
CTF- 1'
Crossroads
PMP / PMP1 Abbreviations
PS = Pump Station
SOI = Sphere of Influence
RW = Recycled Water
Notes
1. NI locations are approximate.
2. The River Islands Pump Stations ( RI -PS and RI Phase 2 PS) pumps to the independent River Islands non - potable water system ( not shown).
Sources
1. Aerial photograph provided by ESRrs ArcGIS Online,
5 May 2025.
800 1, 600
Scale of Feet
Recycled Water Landscape Irrigation Areas
Recycled Water System Master Plan Amendment
Gay of Lelhrop
Lathrop, CA
environment May 2025
c
water e 2
D
2-D2-2D
Section 3
2025 RWSMP Amendment
Recycled Water Infrastructure City of Lathrop
3 RECYCLED WATER INFRASTRUCTURE
As discussed in the Wastewater System Master Plan ( WWSMP) (EKI, 2024b), wastewater generated west of I-5 is collected and treated at the Lathrop CTF. The remaining wastewater is collected and conveyed to the Manteca Water Quality Control Facility ( MWQCF). The Lathrop CTF currently has a capacity of
2. 5 million gallons per day ( MGD) and is anticipated to be expanded to a total of 5. 0 MGD before 2027.
Wastewater treatment and recycled water disposal at the City' s Lathrop CTF is regulated under Waste Discharge Requirements ( WDR) Order No. R5- 2016- 0028-1by the Central Valley Regional Water Quality Control Board ( RWQCB) (RWQCB, 2016). The Lathrop CTF produces disinfected tertiary recycled water suitable for irrigation at parks, landscape strips, median islands, pond berms, and agricultural fields. In 2021, the City obtained an NPDES permit ( Order R5- 2022- 0004) (RWQCB, 2022) for surface water discharge. This permit allows the City to discharge a portion of the treated effluent to the river, while using the remaining portion for meeting landscape irrigation demands and other permitted non -potable uses.
The City is covered under General Order WQ- 2016- 008- DDW (General Order) (SWRCB, 2016) for recycled water use in a total of 196 acres of landscape irrigation areas in the River Islands, Mossdale, and Central Lathrop areas. As described in Section 2., the City' scurrently provides recycled water to 54. 8acres of LI areas. The City completed improvements at the CTF and began discharging treated wastewater effluent to the San Joaquin River in February 2024.
Prior to the implementation of river discharge, the City disposed effluent produced by the CTF by applying the tertiary treated effluent to agricultural LAAs. The City' s existing recycled water system was built to support the disposal of effluent. The system had a disposal capacity of 666 MGD ( RWQCB, 2019) and consisted of 10 storage ponds, their associated pump stations, agricultural LAAs, a percolation pond ( PB1), and approximately 30. miles of recycled water pipeline. The RI -PS pump station was constructed to supply recycled water and other non -potable sources ( San Joaquin River and lake water) to a private distribution system serving landscape irrigation use areas in the River Islands development area. 1 The River Islands' non -potable water system is supplemented by River Islands' other non -potable water sources. For the purposes of this document, it is anticipated that River Islands non -potable demands will be entirely met by the City' srecycled water supply from 2025 and beyond.
With the implementation of river discharge, the City has decommissioned all LAAs, ponds, and associated booster pump stations ( BPSs) except for Pond S5 with its BPS PMP- 1 and Pond S16 with its BPS PMP- 10.
Existing recycled water mains associated with the abandoned ponds and LAAs have also been taken out of service. The decommissioned recycled water facilities are shown on Figure 3-1.
Figure 3-2 shows the City' sservice area and locations of the City' s existing recycled water system facilities and use areas. Detailed description of the City' srecycled water system facilities can be found in the City' s 2019 RWSMP and the 2020 River Discharge Memo ( EKI, 2020).
As discussed further in the following sections, modifications to the retained infrastructure are necessary to optimize the system for a smaller amount of recycled water demands associated with urban landscape irrigation. The design of the proposed facilities is discussed further in Sections 5 and 6.
The City' srecycled water system discharges to the RI - PS wet well for the RI - PS pump stations to deliver recycled water to the RI non - potable water system.
ekienvironment water 3- 1
May 2025
EKI C20049. 03
1 A23
1 Ii
PMP12
20 P61
PMP1
S6
Lepend
ICZ.! Sphere of Influence
Recycled Water Infrastructure to be
Decommissioned
Pipeline
Storage Pond
Percolation Basin
Land Application Area
MI Pump Station
Recycled Water Infrastructure to Retain
Pipeline
Storage Pond
Landscape Irrigation Area
BE Pump Station
Abbreviations
SOI = Sphere of Influence
RW = Recycled Water
Notes
t. AN locations are approximate.
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, 5 May 2025. 4, 000 e, 000
Soak in Fee)
Decommissioned Recycled Water Infrastructure
Recycled Water System Master Plan AmendrreM
co of Lathrop
Lathrop, CA
Mao 2025 ekenvironment 020049. 03 I & water Figure 3- 1 k.
I
DOSREMRe I
raa< no
c' l
fr (') 1
t
1 a
I
w' .../•./• ..........
1 Q, vr4rlo
1.•^ ••
LeUend
Sphere of Influence
Existing Pipe Diameter, Inches
6 - 16
8 20
10 - 24
12 Recycled Water Distribution Infrastructure
Storage Pond
Percolation Basin
Land Application Area
Landscape Imgation Area
Existing Pump Station
Abbreviations
RI -PS = River Islands Pump Station
SOI = Sphere of Influence
RW = Recycled Water
Notes
1. All locations are approximate.
2. The River Islands Pump Station ( RI - PS) pumps to the independent River Islands non - potable water
system ( not shown).
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, 8 May 2025.
4000 8. 000
scale in rear)
Existing Recycled Water System
Recycled water System Mester Plan Amendment
Cdy of Lathrop
Lathrop, CA
eki environment 20 3.- 2
02025
water Figure 3-2
Section 4
Recycled Water Supply, Demand, and Water Balance Evaluation City of Lathrop 2025 RWSMP Amendment
4 RECYCLED WATER SUPPLY, DEMAND, AND WATER BALANCE EVALUATION The following sections provide an evaluation of the City' sfuture recycled water suppliers, demand, and storage requirements based on a water balance analysis.
4. 1 Recycled Water Supply
Table 4-1 shows projected wastewater flows to the Lathrop CTF in 5 -year increments through buildout as estimated in the City' s 2024 WWSMP Amendment ( EKI, 2024b). It is anticipated that future Lathrop CTF expansions will produce up to 4. 31 MGD of tertiary treated effluent at buildout. For the purposes of this RWSMP, recycled water production is assumed to equal wastewater influent flows to the Lathrop CTF. 2 Table 4-1. Projected Recycled Water Supply
Projected Wastewater Flow to CTF
Projected Recycled Water Supply (MGD) la)
2025 2030 2035 2040 2045
1. 51 2. 44 3.7 4. 03 4. 31
Abbreviations:
MGD = million gallons per day
4. 2 Recycled Water Demand
4. 2.1 Current and Historical Recycled Water Demand
The City' slandscape irrigation recycled water demand during 2021 and 2022 is presented in Table 4-2.
The City began providing recycled water to LI areas in July 2021 and provided a total of 94 acre- feet during the months of July through December 2021. The City' srecycled water use in 2022 was 194 acre- feet.
Table 4-2. Current and Historical Recycled Water Use
Water Use Sector
Recycled Water Demand ( a)
Recycled Water Demand ( acre- feet)
2021
94 2022
194
Notes:
a) Recycled water demand based on CalSense meter data.
4. 2. Projected Recycled Water Demand
As shown in the water balance evaluations below, monthly landscape irrigation demands were estimated based on average annual precipitation and evaporation within the City. The resulting total annual recycled water demand per unit area is equivalent to 48. 7ac- inch/ ac. Using the unit area recycled water demand factor, the City anticipates a total recycled water demand of 2. 38 MGD or 2, 669 acre- feet per year ( AFY) by 2045. The projected demand is well below the projected recycled water supply at 4. 31 by 2045.
The City' s projected annual and maximum month recycled water demand in 5 -year increments through buildout ( 2045) is summarized in Table 4-3. This is a significant reduction in projected recycled water 2 A small portion of the wastewater flows are likely lost during the wastewater treatment process. eki environment
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May 2025
EKI C20049. 03
Section 4
Recycled Water Supply, Demand, and Water Balance Evaluation 2025 RWSMP Amendment
City of Lathrop
demand compared to those presented in prior planning documents due to that the City is no longer using the recycled water system to apply CTF treated effluent. Table 4- calculates projected recycled water demand by development area through buildout.
Table 4-3. Projected Average Annual and Maximum Month Recycled Water Demand Units 2025 2030 2035 2040 2045
ac -inch 11, 592 19, 227 25, 323 32, 032 32, 032
Total Annual Demand acre- feet 966 1, 602 2, 110 2, 669 2, 669 MGD 0. 86 1. 43 1. 88 2. 38 2. 38
Maximum Monthly Demand
ac -inch 1, 994 3,07 4, 356 5,10 5,10
MGD 1. 75 2. 90 3. 82 4. 83 4. 83
Abbreviations:
ac -inch = acre -inches MGD = million gallons per day
Table 4-. Projected Average Annual Recycled Water Demand by Development Area Development Area ( a)
Central Lathrop
Projected
2025
146
Recycled
2030
305
Water Demand
2035
325
acre- feet)
2040
445
2045
445
Mossdale 182 217 262 262 262
River Islands 635 1, 078 1, 521 1, 960 1, 960
Lathrop Gateway 0. 81 0. 81 0. 81 0. 81 0. 81
Crossroads 1. 6 1. 6 1. 6 1. 6 1. 6
TOTAL 966 1602 2110 2669 2669
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May 2025
EKI C20049. 03
Section 4 2025 RWSMP Amendment
Recycled Water Supply, Demand, and Water Balance Evaluation City of Lathrop Figure 4-1. Projected Average Annual Recycled Water Demand by Development Area 3000
a
2500
u
c 2000
v
0 1500
c5
a)
a
u
1000
aJ
o • 500
2 2025 2030 2035 2040 Buildout
2045)
Year
Central Lathrop Mossdale River Islands Lathrop Gateway • Crossroads
4. 3 Recycled Water Balance Evaluation
Total projected recycled water demand and seasonal storage requirements were estimated using EKI' s water balance evaluation. The methodology of the water balance evaluation is described below and is consistent with CTF' sformer WDR. The following sections describe the evaluated recycled water balance scenarios, summarize the recycled water storage requirements, and summarize the water balance results.
Detailed water balance evaluations are included in Appendix A.
4. 3. 1 Recycled Water Use Balance Scenarios
Recycled water balance calculations were conducted for the near -term ( 2030) and buildout ( 2045) planning horizons to estimate the final storage needs at buildout as well as any additional storage needs in the near term. The water balance calculations are based on projected wastewater flows to the Lathrop CTF in Table 4-1 and the total projected LI acreage in Table 2- in years 2030 and 2045, respectively.
4. 3.2 Recycled Water Balance Methodology
The recycled water balances summarize system inflows ( CTF effluent, and precipitation) and system outflows ( evaporation, irrigation, and percolation) for an average -year precipitation condition assuming a set average dry weather flow. Evaluation of higher precipitation conditions ( e.g., 100 - year rainfall) is not necessary as the City can now discharge any excess CTF effluent.
Other assumptions made in the water balances are consistent with those made in previously submitted water balances used to support the WDR amendments, and are as follows:
ek, environment
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May 2025
EKI C20049. 03
Section 4 2025 RWSMP Amendment
Recycled Water Supply, Demand, and Water Balance Evaluation City of Lathrop Inflow and infiltration ( I/) are assumed to be 10% of the total annual flow.
Precipitation and evapotranspiration data are based on 1987 to 2024 data from the California Irrigation Management Information System ( CIMIS) station 70 located in Manteca.
Irrigation demands for landscaping are assumed to be 20% Tess than the reference evapotranspiration as there is a combination of high water -use turf and lower -water -use trees and shrubbery.
An irrigation efficiency of 80% is assumed for landscape irrigation. Depending on the irrigation method, actual irrigation efficiencies can range between 70% - 80% for landscape irrigation.
A 10% leaching requirement is assumed in the calculation of the irrigation demand. 90% of the pond surface area is assumed to be subject to evaporation.
An evaporation discount factor of 90% is used in calculation of evaporation from ponds.
A land use efficiency of 95% is assumed.
The pond capacities assume a minimum of two feet of freeboard in all ponds at all times.
4. 3. Recycled Water Balance Results
The projected CTF effluent, required storage, and effluent volume discharged to the river for the near - term ( 2030) and buildout ( 2045) scenarios are summarized in Table 4-5. Figure 4-2 and Figure 4-3 plot the monthly CTF effluent production, recycled water use, and excess effluent to be discharged to the San Joaquin River under each scenario, respectively. The water balance indicates that monthly wastewater effluent exceeds monthly irrigation in all months except for June through August and only
61. 4to 71. 5 MG of seasonal storage is needed to meet this shortfall. This can be met by retaining existing ponds S5 and S16 that have an existing total storage capacity of 129. 5 MG. The available storage from these ponds is sufficient to provide the required seasonal storage and operational storage to meet peak irrigation demands ( see Section 6). The City could elect to reduce the size of these ponds if other beneficial uses of the land area become available. Reducing the storage capacity could help improve water quality. eki environment
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May 2025
EKI C20049. 03
Section 4
Recycled Water Supply, Demand, and Water Balance Evaluation 2025 RWSMP Amendment
City of Lathrop
Table 4-5. Summary of Required Recycled Water Storage and Use Areas Landscape Irrigation Area ( ac)
Near - term ( 2030)
394. 6
Buildout ( 2045)
657. 4
Annual CTF Effluent / Recycled
Water Supply ( MGD)
2. 44 4. 31
Required Storage (MG) 61. 4 71. 5
Annual Recycled Water Demand ( MG) 522. 1 869.
Annual Effluent Volume Discharged ( MG) 405. 3 737. 2
Abbreviations:
ac = acres MG = million gallons MGD = million gallons per day Notes:
a) Based on Water Balance analysis included in Appendix A. eki environment
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May 2025
EKI C20049. 03
Section 4 2025 RWSMP Amendment
Recycled Water Supply, Demand, and Water Balance Evaluation City of Lathrop Figure 4-2. Water Balance Monthly Flow Summary in 2030
180
160
140
120
100
2 80
E
0 60
40 20
0 Jan Feb Mar Apr May
20)
40)
eki environment
water
NM Excess CTF Effluent/ Recycled Water Production
0CTF Effluent/ Recycled Water Production
0—Recycled Water Demand
Oct Nov Dec
4- 6
May 2025
EKI C20049. 03
Section 4 2025 RWSMP Amendment
Recycled Water Supply, Demand, and Water Balance Evaluation City of Lathrop 180
160
140
120
100
2 80
v
E
60 40
20 0
20)
40)
Figure 4-3. Water Balance Monthly Flow Summary at 2045 ( Buildout) Jan Feb Mar Apr May Aug Sep Oct Nov Dec
Excess CTF Effluent/ Recycled Water Production
4D— CTF Effluent/ Recycled Water Production
Recycled Water Demand
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May 2025
EKI C20049. 03
Section 5
Recycled Water System Operation Strategy
2025 RWSMP Amendment
City of Lathrop
5 RECYCLED WATER SYSTEM OPERATION STRATEGY
As discussed in Section 4, the City anticipates a smaller amount of recycled water demands associated with urban landscape irrigation and implementation of river discharge. Only 61. 4to 71. 5 MG of seasonal storage is needed to meet the City' sseasonal recycled water demands under 2030 and 2045 conditions, respectively. This can be met by retaining existing ponds S5 and S16 with a total storage capacity of 129. 5 MG, as summarized in Table 5-1, and their respective booster pump stations PMP- 1 and PMP- 10 with upgrades described below.
Table 5-1. Existing Storage Pond Characteristics
Pond ID Assessor' s Parcel Number
55 S16
198-30- 47
198-30- 48
213-90- 02
Storage Capacity
million gallons) (a)
28 101
Storage Capacity
acre -inches)
1, 048
3, 719
Notes:
a) Storage capacities are rounded to the nearest million gallons.
5. 1 Recommended Recycled Water System Layout
Pump stations PMP- 10 and PMP- 1 will need to be upgraded to supply peak demands and pressurize the recycled water system at the necessary pressures. A significant portion of the City' s buildout recycled water demand will be driven by the River Islands non -potable water system. The City' s recycled water system is planned to connect to River Islands through the existing RI - PS and the future RI Phase 2 PS.
Recycled water will be discharged to the wet wells of these pump stations, which will then pump water into River Islands' distribution system. As such, PMP- 10should be upgraded to meet peak demands at RIPS and RI Phase 2 PS and maintain positive pressures within the City' srecycled water transmission system in River Islands. In addition, PMP- 1 will be upgraded to meet demands and maintain required pressures in areas east of the San Joaquin River.
Due to the high cost of operating and maintaining pump stations and storage ponds, as well as the phased nature of future developments, EKI recommends that the City phase the expansion of the BPSs. This should begin with upgrading and operating the existing PMP- 1, followed by upgrading PMP- 10 when system -wide projected peak demands approach the firm capacity of PMP- 1. Section 7 details the trigger of upgrading PMP- 10.
The recommended buildout recycled system also includes new transmission mains to improve the system' s hydraulic capacity. These new mains are facilities conceptualized previously in backbone infrastructure plans or through discussion with City staff, which are geographically shown on Figure 5-1 and listed below:
Mossdale Landing West development area backbone infrastructure ( EKI, 2024c); and A New 16 -inch transmission main along River Islands Parkway, Cambay Parkway, and Golden Valley Parkway, connecting the RI Phase 2 PS with the City' s existing 16 -inch main on Golden Valley Parkway near Cirrus Court.
A 24 -inch transmission main and railroad crossing that connects PMP- 10 to the new 16 - inch main at the intersection of Cambay Parkway and Golden Valley Parkway. eki environment
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May 2025
EKI C20049. 03
Section 5 2025 RWSMP Amendment
Recycled Water System Operation Strategy City of Lathrop Sections 6 and 7, below, analyze and verify the required BPS and transmission main sizing for the optimized recycled water system. Section 8 presents cost estimates and identifies the parties responsible for the design and construction of these projects.
5. 2 Pressure Zones
To optimize the efficiency of PMP- 1 and PMP- 10 when both pump stations are in operation simultaneously, EKI recommends installing pressure reducing valve ( PRV) stations between portions of the River Islands system and the remaining areas of the City' srecycled water system. This will create two separate pressure zones to improve system performance and reliability. The new PRV stations are intended to maintain appropriate pressure within each zone to meet the City' s design criteria.
The PRVs will be set to remain closed when both PMP- 1and PMP- 10are operating concurrently, and to open when 516 is being filled or when only one pump station is in operation. Each station will be equipped with two sets of low -flow and high -flow PRVs to allow bidirectional water transfer, along with flow meters to monitor volume flowing in both directions between the City and River Islands.
EKI recommends the following PRV locations and pressure settings to ensure the valves remain closed during peak demand conditions. These pressure settings are verified with hydraulic modeling in Section 7 and need to be refined in the design phase when more information becomes available.
PRV- 1: On the existing 16 -inch main along River Islands Parkway between Somerston Parkway and Cohen Road
o From the City to River Islands: 12 psi
o From River Islands to the City: 50 psi
PRV- 2: On the existing 16 -inch main along Manthey Road near the intersection of Manthey Road and Steward Road
o From the City to River Islands: 30 psi
o From River Islands to the City: 45 psi
Additionally, at each connection point between the River Islands' non -potable water system and the City' s recycled water system, pressure sustaining valve ( PSV) stations are recommended to be installed to maintain positive pressure in the City' ssystem during periods of low demand. A PSV station will also be required at S16' sinflow pipe to sustain the pressure during pond filling periods.
This configuration allows the City to manage flows during peak and non -peak seasons and keep the recycled water system pressurized. Section 7. 4 provides further hydraulic evaluations of these recommended modifications.
5. 3 Improving Recycled Water Quality
Algae growth within the City' s storage ponds has been impacting distribution and irrigation system equipment. To address this, the City is exploring options to add filtration or other treatment to the recycled water pumped from the ponds. Additionally, with the reduced recycled water demand projections, only a portion of the existing capacity of ponds S5 and S16 is required to meet peak seasonal demands. As a result, the City could consider reducing the capacity of these ponds or partitioning them into smaller cells, provided that the remaining storage is sufficient to meet the estimated required seasonal storage during average rainfall years of 61. 4 MG by 2030 and 71. 5 MG by 2045. Reducing storage capacity could also help improve water quality and repurpose a portion of the parcel for other beneficial uses.
eki environment
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May 2025
EKI C20049. 03
2_
R± PFiase 2 P5
k 555/
PRV- 1
Upgraded •
PMP- 10 st€
d
1." 5
PRV- 2
Legend
iL1Sphere of Influence
Existing Pipe Diameter, Inches
6 - 16
8 20
10 - 24
12 Future Pipe Diameter, Inches
6 - - - 16 --- 24
8 20
Recycled Water Distribution Infrastructure
Landscape Irrigation Area ( River Islands not shown)
City Pump Station
On Discharge to RI Non - Potable Water System
Storage Pond
Pressure Reducing Valve Station
Abbreviations
PRV = Pressure Reducing Valve
PS = Pump Station
RI = River Islands
RW = Recycled Water
SOI = Sphere of Influence
Notes
1. All locations are approximate.
2. Existing storage ponds, mains, and pump stations storing or conveying treated water to LAAs are assumed to be
abandoned at buildout.
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, 5 May 2025.
N
4, 000 8, 000
Iscele, aPes5
Recommended Buildout Recycled Water System
eki
Recycled Water System Master Clan Amendment
City of Lathrop
Lathrop, CA
environment C2May200W49.3
water Figure 5- 1
Section 6 2025 RWSMP Amendment
System Performance and Design Criteria City of Lathrop
6 SYSTEM PERFORMANCE AND DESIGN CRITERIA
This section summarizes the criteria used to evaluate the City' srecycled water distribution system. These criteria are based on 2022 Lathrop Design and Construction Standards (" Standards"; Lathrop, 2022), the City' s previous master plan analyses, and EKI' s recommendations. A summary of the recycled water system design criteria is provided in Table 6- 2 and described in detail in the following sections. As discussed in Section 7, this RWSMP evaluates system performance in the near term, as the City expects to meet over 90% of its buildout demands by 2030, and at buildout, when River Islands reaches its 100% projected demands by 2045.
6. 1 Distribution System Performance Criteria
6. 1. Peaking Factors
Table 6- 1 summarizes the recycled water distribution system peak factors and peak water demands. The recycled water distribution system performance is evaluated under peak hour demand ( PHD) conditions.
Based on the methodology described below, a City- wide PHD of approximately 12, 569 gpm is anticipated at buildout, including demands of 9, 227 gpm and 3,42 gpm for River Islands and the rest of the City, respectively.
Due to insufficient recycled water meter data, the existing maximum day demand ( MDD) is unknown. The MDD is assumed to equal 1. 25 times the recycled water maximum month demand ( MMD) obtained from the water balance evaluations ( see Section 4.1). Based on the City' s monthly potable water billing data, this is generally consistent with the ratio of the City' s estimated outdoor potable water MDD to MMD in 2022.
With the implementation of bubbler irrigation devices, which apply water near the root zone and limit public exposure to recycled water, the City plans to amend the General Order to allow irrigation during the daytime for drip irrigation of public landscape areas with recycled water. For planning purposes, PHD is estimated assuming that the MDD is applied over an 8 -hour period and thus equals three times the MDD. Due to the lack of existing metering data, these peaking factors are conservative, and EKI recommends that the City reevaluate these factors once more operational data becomes available.
Table 6-1. Peak Recycled Water Demand at Buildout
Recycled Water Demand at Buildout
Peaking Factor (
MGD) ( gpm)
City LI Areas
ADD a) 0. 6 440
MMD a) 1. 3 891
MDD 1. 25 x MMD 1. 6 1,14
PHD 3 x MDD 6. 4 3,42
River Islands Non -Potable Water System
ADD a) 1. 7 1, 215
MMD a) 3. 5 2, 460
MDD 1. 25 x MMD 4. 3, 076
PHD 3 x MDD 17. 7 9, 227
ek, environment
water 6-1
May 2025
EKI C20049. 03
Section 6
System Performance and Design Criteria
2025 RWSMP Amendment
City of Lathrop
Table 6-1. Peak Recycled Water Demand at Buildout ( Continued) Recycled Water Demand at Buildout
Peaking Factor
MGD) ( gpm)
City- wide Total
ADD a) 2. 4 1, 655
MMD a) 4. 8 3,51
MDD 1. 25 x MMD 6. 0 4, 189
PHD 3x MDD 24. 1 12, 569
Abbreviations:
ADD = average daily demand
MMD = maximum month demand
gpm = gallons per minute MGD = million gallons per day
PHD = peak hour demands
Notes:
a) Average daily demand ( ADD) and maximum month demand ( MMD) obtained from Water Balance Evaluations ( see Section 5. 3 and Appendix A) and proportionally attributed to the City LI area and River Islands non -potable water system.
b) Totals may not sum due to rounding.
6. 1. 2 Distribution System Pressures
The distribution system' sability to maintain adequate system pressures during peak demand conditions is the primary indicator of acceptable system performance. The distribution system must maintain 45 psi at LI service connections during peak demand conditions to meet the irrigation controller requirements.
Because non -potable demands the River Islands development area are supplied by an independent non - potable water distribution system that pumps recycled water delivered from the City at the RI -PS and RI Phase 2 PS wet wells, the City' stransmission system in River Islands is only required to maintain positive pressure ( at least 10 psi).
American Water Works Association ( AWWA) Manual M24 — Planning for the Distribution of Reclaimed Water recommends that the recycled water target operating pressure be approximately 10 psi lower than the potable water system. The City' s potable water system currently operates at between 45 psi and 55 psi. Due to the relatively low potable water system pressure, the recycled water distribution system cannot achieve the minimum recycled water system pressure criteria described above with a maximum pressure of 45 psi ( i.e., 10 psi less than the water system). Therefore, the maximum recycled water system pressure criterium is established as 55 psi.
6. 2 Recycled Water System Facilities
6. 2. 1 Recycled Water Transmission and Distribution Pipeline Sizing Criteria Pipeline velocity and head loss criteria will be used for sizing new transmission and distribution pipelines.
However, when evaluating the existing system, velocity and head loss criteria are secondary to the system pressure criteria. For example, if system pressures are satisfied under peak demand conditions, an existing pipe that exceeds maximum velocity or head loss criteria will not necessarily be indicative of a problem that requires system improvements. Any identified exceedances will be reviewed on a case -by -case basis to determine if they are influencing any deficient system pressures or if improving these pipes to meet eki environment
water 6- 2
May 2025
EKI C20049. 03
Section 6 2025 RWSMP Amendment
System Performance and Design Criteria City of Lathrop
velocity or head loss criteria would benefit recycled water movement within the system or increase system redundancy.
6. 2. Velocity Criteria
The following velocity criteria under peak demand conditions, in conjunction with the head loss criteria described below, are recommended for sizing new water mains:
Maximum velocity of 7 feet per second ( fps) for all mains Minimum velocity of 1 fps for all mains
As discussed above, these criteria are secondary to pressure criteria and are evaluated to identify potential bottlenecks in the system that could be upsized to address pressure deficiencies. Minimum velocity criteria are considered to reduce water age and increase water quality.
6. 2. 3 Head Loss Criteria
In addition to velocity criteria, the following head loss criteria under peak demand conditions must also be met for sizing new recycled water mains:
Pipes < 16 inches in diameter: Maximum head loss of 7 feet per 1, 000 feet of pipe ( ft/ k-t) Pipes 16 inches in diameter: Maximum head loss of 5 ft/ k-t The peak demand head loss criteria distinguish between pipes less than 16 inches and those greater or equal to 16 inches in diameter. The larger pipes generally used transmit water long distances from sources to smaller distribution pipelines which serve customer connections.
For existing pipelines these criteria are used to identify bottlenecks in the system that if upsized could relieve downstream pressure to meet pressure criteria and improve system connectivity.
6. 2. 4 Booster Pump Stations
In order to meet peak demand conditions, the City must provide firm pumping capacity with one pump offline at each BPS. This criterion exists to ensure there is sufficient pumping capacity distributed throughout the system to meet peak demand conditions.
As such, the proposed BPS upgrades should be sized for firm capacity equal to PHD under buildout conditions. EKI recommends that the City upgrade the existing PMP- 1 and PMP- 10 to be able to provide flow to meet the projected PHD from City LI areas and the River Islands non -potable water system, respectively, with one ( 1) standby pump at each pump station for system redundancy. Therefore, EKI recommends:
Upgrading the PMP- 1with three main 1,30 gpm variable frequency drive (VFD) pumps and one standby 1,30 gpm VFD pump to provide a firm capacity of 3,90 gpm and total capacity of 4, 520 gpm to supply peak demands of the City area east of San Joaquin River.
EKI recommends a discharge pressure set point of 55 psi and a design point of 125 feet of total dynamic head at the firm capacity.
Expanding PMP- 10 with three main 3, 100 gpm VFD pumps and one standby 3, 100 gpm VFD pump to meet River Islands' projected PHD and maintain positive pressure (> 10 psi) at the discharge locations to the River Islands' non -potable water system.
EKI recommends a discharge pressure set point for PMP- 10 is 55 psi and a design point of 120 feet of total dynamic head at the firm capacity.
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May 2025
EKI C20049. 03
Section 6
System Performance and Design Criteria
2025 RWSMP Amendment
City of Lathrop
EKI recommends that hydropneumatic tanks be installed at each pump station to supply water during low demand periods to limit pump cycling.
Table 6-2. Summary of Recommended Recycled Water System Performance and Operation Criteria Component Criteria Data Sources/ Remarks (a)
RECYCLED WATER SYSTEM PERFORMANCE
Peaking Factors for System Analysis
Maximum
Monthly Demand
Calculated using recycled water balance
Maximum Day to
Maximum Month
Peaking Factor
1. 25 times maximum month demand
EKI recommendation, to be
reevaluated as more data on
system operations is collected
Peak Hour to
Maximum Day
Peaking Factor
3 times average day demand
post river discharge.
Distribution System Pressures
Maximum
Pressure
55 psi system wide
EKI recommendation based on
City' s 2022 potable water system
operational conditions and AWWA
Manual M24 recommendation
Minimum
Pressure
45 psi at urban landscape irrigation service
connections during peak hour demands. At
least 10 psi must be maintained in the
transmission system within River Islands
that delivers recycled water to RI -PS and RI
Phase 2 PS.
EKI Recommendation and the City
of Lathrop 2022 Design and
Demand
Condition to Be
Met
FACILITIES SIZING
Pipelines
Peak Conditions: Provide firm pumping
capacity at each pump station ( one pump
offline at each pump station) and firm
pump station capacity (one storage pond
offline) to meet peak hour demands.
Construction Standards
Minimum
Velocity
1 fps Nolte 2006 RWSMP
Maximum
Velocity
7 fps
Maximum
Head Loss
5 ft/ k-tfor pipes 16 inches in diameter,
peak hour demands
7 ft/ k-tfor pipes < 16 inches in diameter,
peak hour demands
EKI 2019 RWSMP and the City of
Lathrop 2022 Design and
Construction Standards
Hazen Williams
C" Factor
Existing Pipelines = 130
New Pipelines = 140
Pipeline Material All Mains: PVC C900 or C905 Class 150 eki environment
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May 2025
EKI C20049. 03
Section 6
System Performance and Design Criteria
2025 RWSMP Amendment
City of Lathrop
Table 6-2. Summary of Recommended Recycled Water System Performance and Operation Criteria Continued)
Component Criteria Data Sources/ Remarks (a)
FACILITIES SIZING
Recycled Water System Storage and Pumping Capacity Requirement Storage and Disposal
Capacity
Provide sufficient storage and disposal
capacity to accommodate for 100 -year
rainfall based on recycled water balance
analysis.
Waste Discharge
Requirements and Master
Recycling Permit Order
No. R5- 2016- 0028
Pumping Capacity
Firm pumping capacity equal to peak
hour demand.
EKI Recommendation
based on industrial
practices
Abbreviations:
fps = feet per second
PVC = polyvinyl chloride
ft/ k-t = feet per thousand feet psi = pounds per square inch RWSMP = Recycled Water System Master Plan
Notes:
a) Source: Recycled Water System Standards, City of Lathrop Department of Public Works Design and Construction Standards, 2022, unless noted otherwise. ek, environment
water 6-5
May 2025
EKI C20049. 03
Section 7 2025 RWSMP Amendment
Distribution System Hydraulic Assessment City of Lathrop 7 DISTRIBUTION SYSTEM HYDRAULIC ASSESSMENT
EKI updated the City' s existing recycled water system hydraulic model to optimize the design of the City' s distribution system at buildout with implementation of river discharge. The hydraulic model transforms information about the physical facilities and system into a mathematical model that is used to analyze the recycled water system under peak demand conditions. The hydraulic model then generates information on flow, velocity, head loss, and pressure that can be used to assess system performance and identify system capabilities and deficiencies. The hydraulic model can also be used to verify the adequacy of recommended or proposed system improvements.
7. 1 Hydraulic Modeling Approach
To evaluate collection system performance against the hydraulic design criteria presented above, EKI conducted steady- state model simulations under projected buildout peak demand conditions and evaluated pipeline capacity and pressure requirements at LI service connections. The model assumes discontinued use of existing permitted LAAs and ponds/ booster pump stations except S5, S16, PMP- 1, and PMP- 10. The model includes upgrades to BPS PMP- 1 and PMP- 10 described above in Section 6. 2.4. The River Islands non - potable distribution system was not included in this modeling evaluation.
7. 2 Hydraulic Model Update
This section provides an overview of the modeling platform migration process, and the model updates performed to reflect system operations at buildout.
7. 2.1 Model Platform
The City' s existing recycled water system hydraulic model was developed on the Innovyze InfoWater platform by EKI for the 2019 RWSMP. The model has been migrated to Innovyze InfoWater Pro, which provides enhanced analytical tools and higher geographical information system ( GIS) integration capabilities. InfoWater Pro is the same modeling platform used for the City' s potable water system model.
7. 2. Model Construction
The City maintains a GIS geodatabase of its infrastructure assets which was used as the basis of information to construct the recycled water system hydraulic model. EKI updated the City' s GIS database
to add the most recent infrastructure improvements and recycled water use areas and identified and filled data gaps to make sure the GIS database accurately represented the City' s existing utility infrastructure.
Moreover, to model the optimized recycled water system, the infrastructure intended to convey flow to LAAs, percolation ponds, and selected seasonal storage ponds were deactivated in the City' s hydraulic model. Planned BPSs and transmission mains were added to the model.
After importing the City' s
GIS data into the hydraulic model, the following steps were performed to address data gaps, create a fully connected network, and construct the buildout scenario that reflects the optimized recycled water system:
Recently constructed mains were digitized and incorporated into the hydraulic model.
LI areas are delineated and added to the hydraulic model.
Planned transmission mains as described in Section 5. 1 as well as the future RI Phase 2 PS are added to the buildout scenario.
Parcel - level recycled water demands were calculated for LI areas using delineated acreage.
The model network was reviewed and refined for connectivity. eki environment
water 7-1
May 2025
EKI C20049. 03
Section 7 2025 RWSMP Amendment
Distribution System Hydraulic Assessment City of Lathrop Elevations were assigned to each model node by extracting elevations from publicly available light detection and ranging ( LiDAR) data.
Existing PMP- 1 was expanded to a firm capacity of 3,90 gpm with VFD pumps configured at design points described in Section 6. 2.4. Existing PMP- 10 was expanded to a firm capacity of 9, 300 gpm with VFD pumps at buildout.
Hazen -Williams C -Factor of 140 were applied to recently constructed and planned new pipes.
River Islands' projected water demands were evenly distributed at two connections to the City' s system ( i.e., the existing RI - PS and the planned RI Phase 2 PS). These two connections are modeled as demand nodes.
Parcel -level recycled water demand projections of the City' s LI areas were allocated to the nearest node.
7. 2. 3 Model Validation
EKI did not calibrate the existing hydraulic model due to lack of recycled water flow data. Since the existing model was constructed in 2019, the infrastructure conditions are less likely to have significant changes.
Therefore, EKI retained the existing hydraulic model and incorporated the infrastructure improvements since the 2019 RWSMP.
7. 3 Modeling Scenarios
For the purpose of strategically operating and maintaining storage ponds and pump stations, the existing and key planned infrastructure were evaluated under two scenarios: Existing System with PMP- 1 Upgrades ( Near -term - 2030) and Future System with PMP- 1 and PMP- 10 Expansion ( Buildout - 2045).
The Near - term scenario includes recycled water infrastructure as described in Section 3 ( Figure 3-2). This scenario also includes upgrades of the existing PMP- 1, as detailed in Section 6. 2.4, to prioritize meeting the projected 2030 PHD for the City' srecycled water users and deliver water to RI - PS with the remaining pumping capacity. Note that in the near -term scenario, River Islands may not receive the full projected 2030 PHD and may need to supplement the supply with other non -potable water sources. Table 7-1 presents the modeled demands in each scenario.
Table 7-1. Modeled Recycled Water Demands
Modeled Recycled Water Peak Hour Demand ( gpm)
Near -term Buildout
Central Lathrop 1, 436 2, 097
Mossdale 1, 023 1, 233
Lathrop Gateway 4 4
Crossroads 8 8
River Islands 2, 023 (a) 9, 227
Abbreviations:
gpm = gallons per minute
Notes:
a) Modeled recycled water available at the RI - PS location with firm pumping capacity of theupgraded PMP- 1while maintaining 45 psi at the City' s recycled water user locations. ek, environment
water 7-2
May 2025
EKI C20049. 03
Section 7 2025 RWSMP Amendment
Distribution System Hydraulic Assessment City of Lathrop The Buildout scenario incorporates expansions at both PMP- 1and PMP- 10, along with other key planned infrastructure listed in Section 5. 1. Incremental PHDs from both the City LI Areas and River Islands were added in the Buildout scenario as per Section 7.2.
7. 4 Recycled Water Distribution System Hydraulic Evaluation The following sections discuss the hydraulic modeling results for the Near -term and Buildout scenarios.
7. 4. 1 Near -term Scenario Evaluation
Near -term scenario model simulations were evaluated to identify system deficiencies by 2030 with PMP1 expansion and determine the trigger for expanding PMP- 10, as are discussed in the following sections.
7. 4.1. System Pressure
PMP- 1 was configured as discussed in Section 6. 2. 4with all VFD pumps online during peak hours, i.e., both the main pumps and the standby pump are running simultaneously. The near -term scenario assumes that recycled water supply will first meet the City' s 2030 peak demands then deliver flow to River Islands with the remaining pumping capacity.
Modeled results indicate that the distribution system can deliver approximately 2, 023 gpm at the RI - PS location while maintaining 45 psi at each LI service connection across the system, as shown on Figure 7-1.
The modeled pressure at the RI - PS location is approximately 46 psi.
Modeled results show that, as soon as the RI- phase2- PSties into the City' s recycled water distribution system and is in operation, PMP- 1is not expected to provide sufficient head to meet the pressure criteria at all user connections, and PMP- 10 will be required to maintain system pressure.
7. 4.1.2 Pipe Velocity
Model results show pipe velocities are below the maximum velocity criteria of 7 fps at all locations, except in the 12 -inch discharge pipe from PMP- 1 (see Figure 7-2). The modeled velocity in the 12 -inch pipe between PMP- 1 and the Lathrop CTF buildings is approximately 7. 5fps. This exceedance can be addressed by replacing the discharging main with 20 -inch pipes.
7. 4.1.3 Pipe Head loss
As shown on Figure 7-3, modeled head loss results indicate no head loss exceedance in the distribution system, except in the 12 -inch discharge pipe from PMP- 1. The modeled headloss in the 12 -inch pipe between PMP- 1 and the Lathrop CTF buildings is approximately 36 ft/ k-t. This exceedance can be mitigated by replacing the discharging main with 20 -inch pipes. eki environment
water 7- 3
May 2025
EKI C20049. 03
r
I
I
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J
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O
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1, 0
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u -
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RI -PS Lx 1
O O
O
005EMi
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Upgraded SR
pMp- 1
Leoend
7 Sphere of Influence
Existing and Buildout Facilities
City Pump Station
Discharge to RI Non - Potable Water System
Storage Pond
Pipe
Junction Pressure, psi
Less than 45 ( Not Meeting Criteria)
45- 50
50 - 55
55 - 56
Abbreviations
BPS = booster pump station
PHD = Peak Hour Demand
psi = pounds per square inch
SOI = Sphere of Influence
Notes
1. All locations are approximate.
2. Pressure shown are modeled results during PHD.
Available flow at RI -PS is approximately 2, 023 gpm.,
while maintaing at least 45 psi at demand nodes located east of San Joaquin River.
Sources
1. Aerial photograph provided by ESRI' sArcGIS Online,
5 May 2025.
3, 000 6, 000
Scab In Feet)
Near -term Recycled Water System
Hydraulic Evaluation - System Pressure
Receded Water System Master Man Amendment
City or Lathrop
Lathrop, CA
environment CMay2o] 520049, 03
I & water Figure 7- 1
De LIMA RD
7 Leoend
1=1 Sphere of Influence
Existing and Buildout Facilities
City Pump station
Discharge to RI Non - Potable Water System
El Storage Pond
Pipe
Pipe Velocity, fps
Less than 4
4-7
Greater than 7 ( Not Meeting Criteria)
Abbreviations
fps = feet per second
PHD = Peak Hour Demand
PS = pump station
RI = River Islands
SOI = Sphere of Influence
Notes
1. All locations are approximate.
2. Velocities shown are modeled results during PHD, with 2, 023 gprn demand at RI - PS.
Sources
1. Aerial photograph provided by ESRrs ArcGIS Online,
5 May 2025.
A
3, 000 6000
Scale in Feet)
Near - term Recycled Water System Hydraulic
Evaluation - Pipe Velocity during PHD
Recycled Water System Master Plan Amendment
City of Lathrop
Lathrop, CA
May 2025
Ienvironment C2004903
water Figure 7-2
DE UMA RD /
rerer
420
LATHk GP
w' aE
eki
Legend
Sphere of Influence
Existing and Buildout Facilities
City Pump Station
Discharge to RI Non - Potable Water System
MI Storage Pond
Pipe
Pipe Head Loss, ttlk- ft
Less than
3 3-5
5-7
7- 10
Greater than 10
Pipe Head Loss Not Meeting Criteria
Head Loss Exceeds Requirement
Abbreviations
ft/ k-t = feet per thousand feet
PHD = Peak Hour Demand
PS = pump station
RI = River Islands
SOI = Sphere of Influence
Notes
1. All locations are approximate.
2. Headlosses shown are modeled results during PHD, with 2, 023 gpm demand at RI -PS.
Sources
1. Aerial photograph provided by ESRI' sArcGIS Online, 5 May 2025. 3, 000 6, 000
Mule pr, Feet)
Near -term Recycled Water System Hydraulic
Evaluation - Pipe Headloss during PHD
Recycled Water System Master Plan Amendment
CM or Lathrop
Lathrop, CA
025
environment May
9. 03
water Figure 7- 3
Section 7 2025 RWSMP Amendment
Distribution System Hydraulic Assessment City of Lathrop
7. 4.2 Buildout Scenario Evaluation
Model results for the buildout scenario were evaluated to assess system deficiencies at buildout and verify recommended sizes for key planned infrastructure. As such, the following sections discuss how future development and planned infrastructure improvements affect the existing water distribution system facilities.
7. 4.2.1 System Pressure
PMP- 1and PMP- 10 were configured as discussed in Section 6. 2.4. Modeled system pressures indicate that the distribution system can deliver peak demands with the recommended pump station modifications, while maintaining 45 psi — 55 psi at each LI service connection across the system, as shown on Figure 7-4.
The modeled pressures at River Islands connections are approximately 30 psi and 21 psi at the RI - PS and RI- phase2- PS locations, respectively. These pressures are not considered as deficiencies because the City is only required to maintain a positive discharge pressure with peak demands at River Islands' booster pump station wet wells.
7. 4.2. Pipe Velocity
Model results show pipe velocities are below the maximum velocity criteria of 7 fps except 16 - inch pipeline on Somerston Parkway between RI - PS and Lakeside Drive ( Figure 7-5). The modeled velocity in this pipe is approximately 10 fps during PHD.
However, as discussed in Section 6. 2., these exceedances do not necessarily indicate the need to upsize the existing pipes unless the pipe velocities are contributing to pressure deficiencies.
7. 4.2.3 Pipe Head loss
As shown on Figure 7-6, in addition to the exceedance in the PMP- 1 discharge main, head loss results show the following high pipeline head losses, which exceeded the head loss criteria ( 7 ft/ kft for pipes smaller than 16 inches in diameter or 5 ft/ k-t for 16 -inch pipes in diameter or larger).
Approximately 7 ft/ k-t in the future 16 - inch pipeline on Golden Valley Parkway between Cambay Parkway and Cirrus Court
Approximately 7 ft/ k-tin the existing 16 -inch pipeline on Golden Valley Parkway between Somerston Road and Cirrus Court
Approximately 17 ft/ k-t in 16 -inch pipeline on Somerston Parkway between RI - PS and Lakeside Drive
However, as discussed in Section 6. 2.3, these exceedances do not necessarily indicate the need to upsize the existing pipes unless the head losses are contributing to pressure deficiencies. eki environment
water 7-
May 2025
EKI C20049. 03
DE LIMA.
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s REIS RC
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O
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PMP- i .
04 •
1 I
1 1
1 I
LATHROP
I
I
I
I
1 Legend
L Sphere of Influence
Existing and Buildout Facilities
in City Pump Station
Ej Discharge to RI Non - Potable Water System
I. Storage Pond
Pipe
Pressure Reducing Valve Station
Junction Pressure, psi
Less than 45 ( Not Meeting Criteria)
45 - 50
50-5
Greater than 55
Abbreviations
PHD = Peak Hour Demand
PRV = Pressure Reducing Valve
PS = pump station
psi = pounds per square inch
Sol = Sphere of tnfluence
Notes
1. All locations are approximate.
2. Pressure shown are modeled results during PHD.
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, 5 May 2025.
0 3, 000 6, 000
Scale m Feet)
eki
Buildout Recycled Water System
Hydraulic Evaluation - System Pressure
Recycled Water System Master Plan Amendment
Clty of Lathrop
Lathrop, CA
May 2025
environment C2(. 9. 03
water Figure 7- 4
RI Phase 2 PS
r
RI -PS
Upgraded
PMP- 10
sam
1 DE LIMA RD
7 PRV- 2
Upgraded
PMP- 1
L. 1
I
L4THROP
iLOUISF
YOSEMI'
eki
Legend
Sphere of Influence
Existing and Buildout Facilities
In City Pump Station
Discharge to RI Non - Potable Water System
Storage Pond
Pipe
Pressure Reducing Valve Station
Pipe Velocity, fps
Less than 4
4-7
Greater than 7 ( Not Meeting Critena)
Abbreviations
fps = feet per second
PHD = Peak Hour Demand
ps = pump station
RI = River Islands
SOI = Sphere of Influence
Notes
1. All locations are approximate.
2. Velocities shown are modeled results during PHD.
Sources
1. Aerial photograph provided by ESRI' sArcGIS Online,
5 May 2025.
3, 000 6, 000
Scale in Feet)
Buildout Recycled Water System Hydraulic
Evaluation - Pipe Velocity during PHD
Recycled Water System Master Plan Amendment
City of Lathrop
Lathrop, CA
May 2025
environment C2004903
water Figure 75
UPgraded
PMP- 10
s1s
eki
Leoend
Sphere of Influence
Existing and Buildout Facilities
City Pump Station
Discharge to RI Non - Potable Water System
Storage Pond
Pipe
Pressure Reducing Valve Station
Pipe Head Loss, 111k - ft
Less than 3
3-5
5-7
7- 10
Greater than 10
Pipe Head Loss Not Meeting Criteria
Head Loss Exceeds Requirement
Abbreviations
ft/ k-t = feet per thousand feet
PHD = Peak Hour Demand
PS = pump station
RI = River Islands
SOI = Sphere of Influence
Notes
1. AII locations are approximate.
2. Headlosses shown are modeled results under PHD.
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, 5 May 2025.
N o ? 000
scale in Feel)
6000
I
Buildout Recycled Water System Hydraulic
Evaluation - Pipe Headloss during PHD
Recycled Water System Master Plan Amendment
City of Lathrop
Lathrop, CA
environment CMay2015 20049, 03
water Figure 74
Section 8 2025 RWSMP Amendment
Recommended Capital Improvement Program City of Lathrop 8 RECOMMENDED CAPITAL IMPROVEMENT PROGRAM
This section describes the recycled water system CIPs recommended to optimize the design of the City' s distribution system at buildout with implementation of river discharge. Sections 8. 1 through 8. 5 outline the scope and estimated cost for booster pump station upgrades, treatment at the storage ponds, and pipeline improvements to meet the City' s projected recycled water demands while supplying recycled water to River Islands' local non -potable water system. Sections 8. 6 and 8. 7 outline additional efforts recommended to optimize recycled water use and accounting, the scopes of which are recommended to be further refined in the near -future. These projects are recommended in addition to the City' s existing recycled water system CIP, described in Sections 8.
Planning level opinions of probable costs ( OPCs) are developed based on bid information from recent similar projects in California. This is a conceptual level estimate, considered to have an estimated accuracy range of -30% to + 50%, suitable for use for budget forecasting, CIP development, and project evaluations, with the understanding that refinements to the project details and costs would be necessary as projects proceed to design and construction. The OPC for construction is presented in December 2024 dollars based on Engineering News Record ( ENR) Construction Cost Index ( CCI) of 13, 632. 41 (20 -city average).
The total CIP OPC also includes allowances equal to 60% for construction contingency ( 30%), design ( 15%), construction management ( 5%), permitting ( 5%), and project implementation ( 5%).
Table 8-1 summarizes the EKI recommended CIPs and the City' s existing CIPs with their estimated planning level OPCs. The estimated OPC totals $ 17. 8 million for City CIP projects. Figure 8- 1 shows an overview of the distribution system project locations and improvements. eki environment
water 8- 1
May 2025
EKI C20049. 03
Section 8
Recommended Capital Improvement Program
2025 RWSMP Amendment
City of Lathrop
Table 8-1. Summary of Recommended Recycled Water System Capital Improvement Projects Project # Improvement Description OPC ( a)
City Projects
RW- 1 Pump Station PMP- 1 Upgrade 6, 060,00
RW- 2 Pump Station PMP- 10 Upgrade 10,20, 000
RW- 3 Treatment at Storage Ponds S5 and S16 1, 547, 000 (b) RW- 6 Conversion of Potable Irrigation Areas to Recycled Water TBD ( c) RW- 7 Recycled Water Metering and Billing Improvements TBD ( c) RW- 8 Recycled Water Operations and Permitting ( City RW 23- 02) 69, 915 (d) Total City CIP OPC 17, 797, 000
Developer Funded Projects
RW- 4 River Islands Phase 2 Backbone Main Improvement 17, 880, 000 RW- 5 Pressure Reducing Valve Station Improvement 860, 00 Abbreviations:
CIP = capital improvement projects OPC = Opinion of Probable Construction Cost Notes:
a) Detailed costs for RW- 1, RW- 2, RW- 4 and RW- 5 are estimated in following sections and are presented in December 2024 dollars.
b) Costs for RW- 3are based on estimates provided by City staff on 7 February 2025. c) Projects RW- 6and RW- 7 are recommended to be further refined in the near future. d) Costs for RW- 8 was carried over from the City' sCapital Improvement Programs Fiscal Years 2023 - 2025 ( Lathrop, 2023).
e) Total may not sum due to rounding.
eki environment
water 8- 2
May 2025
EKI C20049. 03
f
1"
RW- 5: Pressure Reducing Valve
Station Improvement
RW- 4: River Islands Phase 2
Backbone Main Improvement
RW- 2: PMP- 10
Upgrades
W- S: Treatm - nt at
Ponds SS and S16
4 1 I
I
I
I
RW- 1: PMP- 1/
Upgr, s••
I
Legend
T! Sphere of Influence
Future Pipe Diameter, Inches
20 8
Recycled Water Distribution Infrastructure
Landscape Irrigation Area
City Pump Station
Discharge to RI Non - Potable Water System
MI Storage Pond
Existing Pipe
Pressure Reducing Valve Station
Abbreviations
LAA = land application area
RI = River Islands
RW = Recycled Water
SOI = Sphere of Influence
Notes
1. All locations are approximate.
2. Existing storage ponds, mains, and pump stations storing or conveying treated water to tAAs are assumed to be
abandoned at buildout.
Sources
1. Aerial photograph provided by ESRI' s ArcGIS Online, 5 May 2025.
N c
A _
4, 000 8000
Soak Jr, Feet,
eki environment
water
Recommended Recycled Water
System Improvements
Recycled Water System Master Plan Amendment
City of Lathrop
Lathrop, CA
May 2025
C20049. 03
Figure 8- 1
Section 8 2025 RWSMP Amendment
Recommended Capital Improvement Program City of Lathrop
8. 1 Pump Station PMP- 1Upgrade
This project includes installing new pumps at the existing PMP- 1 near pond S5 with the capacity as designed in Sections 6. 2. 4and verified via hydraulic modeling. In addition, this project addresses the exceedances in pipe velocity and head loss criteria near PMP- 1. This project consists of:
Upgrading PMP- 1 to provide a firm capacity of 3,90 gpm and total capacity of 4, 520 gpm with three main 1,30 gpm VFD pumps and one standby 1,30 gpm VFD pump; Installing a new hydropneumatic tank to supply low demand without cycling or continuously operating the pumps; and
Replacing approximately 520 linear feet ( LF) of 12 -inch discharging main with 20 -inch PVC pipe and appurtenances to connect the PMP- 1 to the existing 20 -inch main in the CTF.
The planning level OPC for this project is estimated in Table 8-2 and totals $ 6. 1 million. It is also recommended that the City update its recycled water peaking factors as discussed in Section 8. 7and verify the sizing of the pump station upgrade.
Table 8-2. Project RW- 1 Details and OPCs
Improvement
Improvement Description Quantity
Type
OPC ( a)
Upgrade
Booster Pump
Station PMP- 1
1) Install a new booster pump station with
firm pumping capacity of 3,90 gpm and
1,30 gpm standby pumping capacity, and ( 2)
install a new hydropneumatic tank
1 LS 3,20, 000
New Pipeline
Replacing existing 12 -inch discharging lines
with 20 -inch PVC pipes
520 LF 265,00
Construction Contingency (30%) 1, 075, 500
Construction OPC 4, 661, 000
Engineering and Administration Costs ( 30%) 1, 398, 000 Total OPC 6, 060,00
Abbreviations:
gpm = gallons per minute OPC = Opinion of Probable Construction Cost Notes:
a) Total may not sum due to rounding.
8. 2 Pump Station PMP- 10 Upgrade
This project includes installing new pumps at the existing PMP- 10 near pond 516 with the capacity as designed in Sections 6. 2. 4and verified via hydraulic modeling. This project consists of:
Upgrading PMP- 10to provide a firm capacity of 9, 300 gpm and total capacity of 12, 400 gpm with three main 3, 100 gpm VFD pumps and one standby 3, 100 gpm VFD pump; and Installing a new hydropneumatic tank to supply low demand without cycling or continuously operating the pumps.
eki environment
water 8- 4
May 2025
EKI C20049. 03
Section 8
Recommended Capital Improvement Program
2025 RWSMP Amendment
City of Lathrop
The planning level OPC for this project is estimated in Table 8- 3 and totals $ 10. million. It is also recommended that the City update its recycled water peaking factors as discussed in Section 8. 7and verify the sizing of the pump station upgrade.
Improvement
Type
Upgrade
Booster Pump
Station
PMP- 10
Table 8-3. Project RW- 2 Details and OPCs
Improvement Description
Install a new booster pump station with firm
pumping capacity of 9, 300 gpm and 3, 100 gpm
standby pumping capacity, and ( 2) install a
new hydropneumatic tank
Quantity OPC ( a)
1 LS 5, 991, 000
Construction Contingency ( 30%) 1, 797, 300
Construction OPC 7,88, 000
Engineering and Administration Costs ( 30%) 2, 336, 000 Total OPC 10,20, 000
Abbreviations:
gpm = gallons per minute OPC = Opinion of Probable Construction Cost Notes:
b) Total may not sum due to rounding.
8. 3 Treatment at Storage Ponds 55 and S16
This project includes adding filtration or other treatment to the recycled water pumped from ponds S5 and S16 to improve recycled water quality. A preliminary cost estimate based on information provided by City staff on 7 February 2025 totals $ 1. 5 million.
In addition, as discussed above, the City may partition these ponds to improve water quality and reduce maintenance requirements, as discussed in Section 5.2. The potential alternative improvements may be re -grading the existing pond, installing additional berms, or other methods appropriate to the site conditions. The cost may vary depending on the final design of the pond.
8. 4 River Islands Phase 2 Backbone Main Improvement
As discussed in Sections 5 and 7, a new transmission main is required to meet River Islands' peak demands and convey water from PMP- 10to River Islands' non -potable water system. This improvement will be part of a backbone recycled water loop in the River Islands area and includes:
Installing approximately 20, 460 LF of the new 16 -inch PVC pipeline along the River Islands Parkway, Cambay Parkway, and Golden Valley Parkway , connecting the RI Phase 2 PS and the City' s existing 16 -inch recycled water main at the intersection of Golden Valley Parkway and Cirrus Court.
Installing approximately 2, 970 LF of the new 24 -inch diameter pipeline with railway crossing, between PMP- 10 and the future 16 -inch main on Golden Valley Parkway.
The total OPC of this project is estimated in Table 8-4and totals $ 17. 9 million. This project is anticipated to be funded and constructed by River Islands or its private developers. eki environment
water 8-5
May 2025
EKI C20049. 03
Section 8
Recommended Capital Improvement Program
2025 RWSMP Amendment
City of Lathrop
Table 8-4. Project RW- 4 Details and OPCs
Improvement
Type
Improvement Description Quantity OPC ( a)
New Pipeline
Install a new 16 -inch diameter pipeline, along
River Islands Parkway, Cambay Parkway, and
Golden Valley Parkway, connecting the RI Phase
2 PS and the City' s existing 16 -inch main at the
intersection of Golden Valley Parkway and Cirrus
Court.
20, 460 LF 8, 389, 000
New Pipeline
Install a new 24 -inch diameter pipeline with
railway crossing, along Cambay Parkway
between PMP- 10 and Golden Valley Parkway.
2, 970 LF 1, 841, 000
Railroad
Crossing
Construct 100 LF of railroad crossing using auger
boring in stable soils.
1 LS 350, 00
Construction Contingency (30%) 3, 174, 000
Construction OPC 13, 754, 000
Engineering and Administration Costs ( 30%) 4, 126, 000 Total OPC 17, 880, 000
Abbreviations:
LF = linear feet LS = lump sum OPC = Opinion of Probable Construction Cost Notes:
a) Total may not sum due to rounding.
b) This project is anticipated to be completed by River Islands.
8. 5 Pressure Reducing Valve Station Improvement
The improvement includes installing two new PRV stations, along with flow meters, as discussed in Section
5.2. These installations are intended to create two pressure zones within the City , optimizing system performance when both upgraded pump stations PMP- 1 and PMP- 10 are in operation.
Each PRV station will consist of two sets of low -flow and high -flow PRVs and associated piping, enabling bidirectional water transfer between the pressure zones. The PRVs will be set to remain closed when both PMP- 1 and PMP- 10 are operating concurrently, and to open when S16 is being filled or when only one pump station is in operation. Flow meters will be installed at each station to monitor the volume of water passing through in each direction.
The recommended PRV station locations are:
On the existing 16 -inch main along River Islands Parkway between Somerston Parkway and Cohen Road.
On the existing 16 -inch main along Manthey Road near the intersection of Manthey Road and Steward Road.
Table 8- 5 provides the detailed OPC for the recommended improvements for this project. The total estimated cost for this project is $ 860, 00. This project is expected to be funded and constructed by River Islands or its private developers.
kienvironment water 8-6
May 2025
EKI C20049. 03
Section 8
Recommended Capital Improvement Program
2025 RWSMP Amendment
City of Lathrop
Table 8-5. Project RW- 5 Details and OPCs
Improvement
Type
Improvement Description Quantity OPC ( a)
New Pressure
Reducing
Valves and
Meters
Install two new PRV stations, each equipped with
two sets of low -flow and high -flow PRVs and
associated piping, at the following locations to
create separate pressure zones and enable
bidirectional water transfer between zones.
1) on the existing 16 -inch main along River
Islands Parkway, between Somerston
Parkway and Cohen Road
2) on the existing 16 -inch main along
Manthey Road near the intersection of
Manthey Road and Steward Road
Install flow meters in the same vaults to monitor
and record the volume of water passing through
each PRV station.
2 LS 506, 000
Construction Contingency ( 30%) 151, 800
Construction OPC 658, 000
Engineering and Administration Costs ( 30%) 197, 000
Total OPC 860, 00
Abbreviations:
LS = lump sum OPC = Opinion of Probable Construction Cost Notes:
a) Total may not sum due to rounding.
b) This project is anticipated to be completed by River Islands.
8. 6 Conversion of Potable Irrigation Areas to Recycled Water As shown in Table 2-1, the City is currently irrigating the following parks and sites with potable water and plans to switch these sites to using recycled water in the near future:
Leland and Jane Stanford Park
Part of the Mossdale Landing Community Park
River Park North
River Park South
Streetscape on Carnaby Road
Streetscape on Golden Valley Parkway between River Islands Parkway and Brookhurst Boulevard Streetscape on Village Avenue between Golden Spike Trail and Towne Centre Drive William S. Moss Park
eki environment
water 8- 7
May 2025
EKI C20049. 03
Section 8 2025 RWSMP Amendment
Recommended Capital Improvement Program City of Lathrop Converting these areas to recycled water may include installation of new recycled water laterals and/ or irrigation equipment. The cost of converting these parcels to recycled water will be site -specific.
8. 7 Recycled Water Metering and Billing Improvements
The City' s recycled water LI areas are equipped with CalSense irrigation controllers to regulate and monitor irrigation water use. These sites are also equipped with customer meters at water and recycled water service connections. However, during the development of the 2024 IWRMP Amendment, the City and EKI discovered discrepancies between the data from CalSense controller flow data and the City' s billing records. Moreover, the City' s billing system does not differentiate between potable and recycled water use at individual sites.
To enhance system performance monitoring and metering accuracy, EKI recommends that the City Implement a system to separately track potable and recycled water use in billing records; Reconcile recycled water use recorded by CalSense irrigation controllers with customer meters; and
Calibrate CalSense irrigation controllers and customer meters regularly to ensure accuracy.
These monitoring improvements are crucial for verifying system demands and peaking factors, as well as supporting further design of infrastructure improvements recommended herein.
8. Recycled Water Operations and Permitting
The City' scurrent CIP RW 23- 02 includes updating the City' s recycled water program to meet changes in reporting, testing, and compliance requirements outlined in the State' s permitting documents. A total of 69, 915 for RW 23- 02 was budgeted in the City' scurrent CIP ( Lathrop, 2023). ek,I & water 8-
May 2025
EKI C20049. 03
Section 9
References
2025 RWSMP Amendment
City of Lathrop
9 REFERENCES
AWWA, 2018. Manual M24 Planning for the Distribution of Reclaimed Water. American Water Works Association, published January 20018.
DTSC, 2011. Vapor Intrusion Mitigation Advisory. California Environmental Protection Agency, Department of Toxic Substances Control, published October 2011.
EKI, 2019a. Wastewater System Master Plan, City of Lathrop Integrated Water Resources Master Plan Update. EKI Environment & Water, Inc., published December 2019.
EKI, 2019b. Water System Master Plan, City of Lathrop Integrated Water Resources Master Plan Update.
EKI Environment & Water, Inc., published December 2019.
EKI, 2019c. Recycled Water System Master Plan, City of Lathrop Integrated Water Resources Master Plan Update. EKI Environment & Water, Inc., published December 2019.
EKI, 2020. Technical Memorandum: CTF Effluent Discharge and Recycled Water Systems Operations.
EKI Environment & Water, Inc., published 13 May 2020.
EKI, 2024a. Draft Recycled Water System Master Plan Amendment, City of Lathrop Integrated Water Resources Master Plan. EKI Environment & Water, Inc., draft dated March 2024.
EKI, 2024b. Wastewater System Master Plan Amendment, City of Lathrop Integrated Water Resources Master Plan. EKI Environment & Water, Inc., published December 2024.
EKI, 2024c. Technical Memorandum: Hydraulic Evaluation for the Mossdale Landing West Development.
EKI Environment & Water, published 28 February 2024.
Lathrop, 2016. City of Lathrop Municipal Service Review And Sphere Of Influence Plan. City of Lathrop, published 14 April 2016.
Lathrop, 2022a. City of Lathrop General Plan, August 2022. City of Lathrop, published August 2022.
Available at: https:// Iathrop. generalplan. org/
Lathrop, 2022b. River Islands Phase 2 Project. City of Lathrop, last updated in 2022. Available at:
https:// www. ci. lath rop. ca. us/ planning/ page/ river- islands- phase- 2project Lathrop, 2022c. City of Lathrop Department of Public Works Design & Construction Standards.
City of Lathrop, last updated in 2022. Available at:
https:// www. ci. lathrop. ca. us/ publicworks/ page/ design- construction- standards Lathrop, 2023. Capital Improvement Programs Fiscal Years 2023-025. City of Lathrop, last updated in 2023. Available at: https:// www. ci. lathrop. ca. us/ finance/ pag/ budget SWRCB, 2016. Order WQ- 2016- 008- DDW Water Reclamation Requirements for Recycled Water Use.
California State Water Resources Control Board, published 7 June 2016.
RWQCB, 2016. Order R5- 2016- 0028- 1Waste Discharge Requirements and Master Recycling Permit for City of Lathrop, Lathrop Consolidated Treatment Facility, San Joaquin County. California Regional Water Quality Control Board Central Valley Region, published 21 April 2016.
RWQCB, 2019. Revised Monitoring and Reporting Program R5- 2016- 0028-2 REV2 for City of Lathrop, Lathrop Consolidated Treatment Facility, San Joaquin County. California Regional Water Quality Control Board Central Valley Region, published 23 September 2019.
RWQCB, 2022. National Pollutant Discharge Elimination System ( NPDES) CA0085359 Order R5- 2022- 0004, Waste Discharge Requirements for the City of Lathrop Consolidated Treatment Facility, San Joaquin ekienvironment water 9-1
May 2025
EKI C20049. 03
Section 9
References
2025 RWSMP Amendment
City of Lathrop
County. California Regional Water Quality Control Board Central Valley Region, published 14 March 2022.
eki environment
water 9-2
May 2025
EKI C20049. 03
2025 RWSMP Amendment
City of Lathrop
APPENDIX A
Water Balance Calculations
eki environment
water
fo
Assumpt
Flo
Requir
Efficien
Tree
App
00 00
Requ0
80 80
Area
Catch
Stor
To
fo
Ev
Evapo ratio Disco un
90 Ave rage Irriga
tion
Requirement
Precipitation/ Evaporation
Date
ApplicationArea
Storage
and
Percolation
Ponds
River
Discharge
Month
Day:
Preap in.
Eff.
Precip. in
ET, in.
Demand,
in
ac Inflow. ac -
inOutflow. ac -
inolu
V
ac -
in
Volume,
ac -
in
LAA
LI
Trees 8
Shrubs
NNW
Precip
Evap
Percolation
Total
Irrigation
Change
Net
Jan31
235
124
1. 06
0. 0
0. 0
0. 0
3. 184
60 19
0 0
3,
226
2, 256
3225. 6
Feb
28 2.
0 18
1. 87
88 1. 3
0. 7
0. 2. 2
805
48 33
0 265
2, 554
2, 256
2554 4
Mar
31 1. 76
0. 62
3. 53
4. 1
2. 1. 9
9 2,
950
39 63
0 1,
076
1. 851
2 .
256
1850. 6
Apr
30 0. 97
021
4. 99
7. 1
5. 3
3. 2, 9
680
21 88
0 1,
970
643
2 ,
256
6428
May
31 0. 58
0. 6.
06 9.
73 4
7. 0
5. 2
2. 670
t
3 119
0 2,
629
65 2 ,
191
0 0
Jun
30 0. 12
0. 00
7. 56
11. 1
8. 6. 3
2 2, 479
3 134
0 3,
109
761
1,
430
0 .
0 Jul
31 0
02 0. 00
7. 98
11. 8.
8 6. 8
6 2, 537
0 142
0 3,
307
911
518
0. 0
Au
g
31 0. 03
0 00
7. 08
10. 7.
4 8
5 9
2, 539
1 126
0 2,
932
518
9 0 .
0 Sep
30 0. 14
000
523
7. 6
5. 7
4. 3
2. 483
3 93
0 2,
140
253
2. 256
0 .
0 Oct
31 0.
68 0
09 3.
39 4
7 3. 5
2 6
2. 694
15 80
0 1,
325
1. 324
2,
256
1324
3 Nov
30 1. 29
0. 36
1. 66
1. 8
1. 3
0. 8
2, 756
28 29
0 474
2, 280
2 ,
256
2280. 2
Dec
31 2. 05
0 79
1. 01
0 1
0. 0
0. 0
3,
020
45 18
0 0
3,
047
2,
256
3046. 7
Annual
Total
385
12 6
52. 1
69 3
51. 3
37. 7
32. 798
276
924
19, 227
12. 922
22, 188
14, 125
Monthly
Average
30 1. 0
4. 3
5 8
4. 3
3. 1
2, 733
23 77
1. 602
1,
077
1,
849
1,
244
Daily
Average
1 0. 0
0. 1
0 19
0. 14
0. 10
90 3
0 53
35 61
41 Peak
Season
Daly
0. 4
0. 3
0. 2
fo
Assu
Flow
MG
To
10 A
Scenari
Effe
Po
MG
Applicatio
Assumptio
Applicatio
V ege
Tree
10 0
IrrigatioEffic
80 As
umpt
0 0
Mo
To
Ev
Evapo Discou
90 Average
Irrigation
PreRequirement cipltationlEvaporation
Data
Application
A
rea
Storage Percoand
lation
Ponds
River
Discharge
Month
Days
Precip
tn
Eff
Precip. in.
in
ET,.
Cemand,
mac
Inflow,
ac -
in
Outflow ac -
in
Volume.
ac -vo
in
ac -
m
LI
Trees Shru8
bs Precip.WW
Evap
Percolation
Total
Irrigation
Change
Net
Jan
31 2. 75
1. 24
1. 06
0 0
0. 0
5,
624
60 19
0 0
5,
666
2,
626
5665. 9
Feb
28 2. 18
0. 87
1 86
1 3
0 7
0. 2
4, 955
48 33
0 442
4, 527
2,
628
4527 .
4 Mar
31 1
78 0
62 3
53 4
1 2
9 1. 9
5,
211
39 63
0 1,
792
3,
395
2,
628
3395. 3
Apr
30 0
0. 97
21 499
7 1
5 3. 3
9 4,
734
21 88
0 3 .
282
1,
385
2,
626
1384 .
7 May
31 0. 58
006
6 73
9 4
7 5. 0
2 4, 717
13 119
0 4, 380
231
2,
626
231 .
0 Jun
30 0.
12 0.
00 7. 56
11. 1
8 3
6. 2
4, 380
3 134
0 5, 180
932
1, 694
0 .
0 Jul
31 0. 02
0. 00
7. 98
11. 8
88 6. 6
4, 481
0 142
0 5, 510
1 ,
170
524
0 .
0 Aug
31 0. 03
0. 00
7. 08
10 4
7 8
5. 9
4, 485
1 126
0 4, 884
525
0 0 .
0 Sep
30 0. 14
0. 00
5. 23
7 6
5 7
4. 3
4,
386
3 93
0 3 .
565
731
2 .
626
0. 0
Oct
31 0.
68 0
09 3. 39
4 7
3. 5
2 6
4, 759
15 60
0 2,
207
2,
507
2. 626
2508. 9
Nov
30 1.
29 0
36 1.
06 1
8 1. 3
0 8
4, 867
28 29
0 790
4, 076
2. 626
4076. 2
Dec
31 2. 05
079
1. 01
01 0. 0
0. 0
5,
334
45 18
0 0
5, 361
2 .
626
5361 .
0 Annual
Total
365
12. 6
4. 2
52. 1
69. 3
51. 3
37. 7
57, 934
275
24 0
32. 032
25, 253
25. 853
27, 148
Mon
thly
Average
30 1. 0
4. 3
5 8
4. 3
3. 1
4,
828
23 77
0 2
669
2,
104
2 154
2,
262
Daily
Average
1 0.
0 0.
1 0
19 0.
14 0. 10
159
88 89
7 74
Peak
Season
Daily
0 4
0. 3
0. 2
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