Agenda packet — Lathrop City Council, October 13, 2025 (part 2 of 4)

SSJID '
BPS - 5
L.

LATHRO'
SSJID
Tumout 1 I

LOUISEAV
Ta
x
WTFTank
a
d BPS
BPS -2
Tank
Well 21 Tank.•
land BP, S#

YOSEMITE AV
Legend
L1Sphere of Influence
Existing Infrastructure
Treatment Plant
Pump Station
Enclosed Storage Facility
SSJID Turnout
Pipe
Buildout Facilities
MI Pump Station
Enclosed Storage Facility
SSJID Turnout
Available Fire Flow, Gallons per Minute
Less than 1250
i 1250- 2000
O 2000 - 3000
3000 - 4000
C Greater than 4000
Hydrant Residual Pressure Not Meeting Criteria
Residual Pressure Below Requirement
Abbreviations
BPS = booster pump station
gpm = gallons per minute
LAWTF = Louise Avenue Water Treatment Facility
SOI = Sphere of Influence
SSJID = South San Joaquin Irrigation District
Notes

1. NI locations are approximate.

2. Well 21 is not active in the buildout system analysis.

3. SSJID Turnout 1 is operating at 3, 900 gpm flow rate in the buildout modeling scenarios.

4. Evaluated with fire pumps online at booster pump
stations where effluent pressure drops below effluent
pressure set points.

Sources

1. Aenal photograph provided by ESRI' s ArcGIS Online,
13 November 2024.

N
3000 6, 000
some tr, Peen
Buildout Water System Hydraulic Evaluation
Maximum Day Demands - Available Fire Flow
Water System Master Plan Amendment
coy or Lathrop
Lathrop, DA
rnber eki environment DeceC2006920 c2004s 01
water Figure 7- 10
Turnout 2
Tank
285
Section 8
2024 WSMP Amendment
WATER SUPPLY, STORAGE, AND PUMPING CAPACITY EVALUATION City of Lathrop 8 WATER SUPPLY, STORAGE, AND PUMPING CAPACITY EVALUATION This section evaluates the City' s water system storage and pumping capacity to meet the recommended performance and operational criteria described in Section 6. 2 under existing and future scenarios. Note that the demands used for sizing these facilities include landscaping and park demands which may be supplied by recycled water in the future. If recycled water is used to supply these demands, then the City can opt to reduce facility sizing requirements accordingly.

8. 1 Existing Water System Evaluation
As discussed below, the City' s existing water system currently has sufficient storage and pumping capacity to meet performance criteria.

8. 1. Water Supply Capacity
The City' s required supply capacity must be greater than MDD. This supply capacity can currently be provided by the firm pumping capacity at the existing SSJID Turnout 1, SSJID Turnout 2, and the LAWTF.

Table 8-1 presents a summary of required and existing firm supply pumping capacity and indicates that the City currently has a supply pumping capacity of approximately 13, 400 gpm, and a surplus capacity of approximately 7, 800 gpm.

8. 1. 2 Water Storage Capacity
The City' s required storage capacity is composed of equalization ( 25% of MDD), fire ( 0. 72 MG based on concurrent industrial and high -density residential fires of 2, 000 and 4, 000 gpm with durations of two hours), and emergency storage ( 75% of MDD). Total existing required storage is equal to 8. 7 MG.

The City currently has 7. 4 MG of storage between LAWTF and Tanks 1 through 6. In addition, the City has a groundwater credit of 4. 5 MG ( see Section 6. 2.3.4). 18 Thus, the City currently has a storage surplus of

3. 1 MG. Table 8-2 provides a summary of existing storage requirements and capacity.

8. 1. 3 Peak Pumping Capacity
The City' srequired peak pumping capacity is equal to the greater of MDD plus concurrent industrial and high -density residential fires or PHD. Peak pumping capacity can be met with a combination of the existing SSJID Turnout 1, the LAWTF, and the BPSs associated with each Tank. The total firm capacity of these pumps is approximately 38, 200 gpm.

Existing MDD is equal to approximately 5,00 gpm and the two concurrent fires are equal to 6, 000 gpm.

Thus, MDD plus fire flow pumping requirement is equal to approximately 11, 500 gpm. PHD pumping requirement is approximately 8, 500 gpm. Therefore, MDD plus fire flow pumping requirements governs.

Table 8- 3 provides an evaluation of firm pumping capacity and indicates that the City currently has a surplus pumping capacity of approximately 26, 600 gpm.

Groundwater credit is calculated as the firm capacity of the wells with backup power ( i.e., with highest -capacity well with backup power out of service) over an 18 -hour period. This is equal to the 18 -hour maximum capacity of Wells 6, 7, and 8. Well 10 is not included because it is highest - capacity well with backup power. Well 9 is temporarily offline due to water quality issues. The City currently don' thave plan to put Well 21 back online. ekienvironment water 8-1
December 2024
EKI C20049. 01
286
Section 8

WATER SUPPLY, STORAGE, AND PUMPING CAPACITY EVALUATION
2024 WSMP Amendment
City of Lathrop
Table 8-1. Existing Water Supply Capacity
Supply Component
Required or Available Firm Supply
Capacity ( a)
gpm MGD
Available Supply Capacity
SSJID Turnout 1 BPS Firm Capacity ( b) 5, 210 7. 5
LAWTF Production Capacity ( c) 4, 150 6. 0
SSJID Turnout 2 BPS Firm Capacity ( b) 4, 000 5. 8
Total Supply Capacity 13, 360 19. 2
Required Supply Capacity Existing Maximum Day Demand ( d) 5,62 8. 0 Notes:
a) Firm pumping capacity reflects the capacity of the pumping station with the largest pump offline. b) Refer to Table 3-1.
c) LAWTF production capacity equals the firm of capacity of Wells 6, 7, and 8. Well 10 is not included because it is highest -capacity well. Well 9 is temporarily offline due to water quality issues. d) Refer to Table 7-1.

Table 8-2. Existing Water Storage Capacity and Requirements Available Storage Capacity
Tank Storage Capacity (a) 7. 4
Groundwater Credit ( b) 4. 5
Total Storage Capacity 11. 9
Required Storage Capacity
Operational 2. 0
Fire ( c) 0. 7
Emergency
Total Required Storage

6. 0

8. 7
Notes:
a) Tank storage capacity includes total capacity of Tanks 1, 2, 3, 4, 5, 6 and the LAWTF Tank. The tank storage capacity does not include the tank at the SSJID turnouts, which are not City facilities. b) Groundwater credit is calculated as the firm capacity of the wells with backup power ( i.e., with highest - capacity well with backup power out of service) over an 18 -hour period. This is equal to the 18 -hour maximum capacity of Wells 6, 7, and 8. Well 10 is not included because it is highest -capacity well with backup power. Well 9 is temporarily offline due to water quality issues. The City currently does not have plan to put Well 21 and Well 21 WTF back online.
c) Required fire storage for one high density residential ( 2, 000 gpm) fire and one industrial or heavy commercial fire ( 4, 000 gpm).
eki environment
water 8- 2
December 2024
EKI C20049. 01
287
Section 8

WATER SUPPLY, STORAGE, AND PUMPING CAPACITY EVALUATION
2024 WSMP Amendment
City of Lathrop
Table 8-3. Evaluation of Existing Firm Pumping Capacity Firm Capacity (a)
Pumping Component
gpm MGD
Available Pumping
Capacity
SSJID Turnout 1 5, 210 7. 5
LAWTF BPS 6, 300 9. 1
BPS - 1 1, 050 1. 5
BPS -2 3, 000 4. 3
BPS - 3 4, 750 6. 8
BPS -4 4, 600 6.

BPS - 5 8, 000 11. 5
BPS -6 5, 300 7. 6
Total Available Firm Pumping Capacity 38, 210 55. 0
Criteria 1: Max Day
Plus Fire Flow
Max Day Plus Two Concurrent Fires ( b) 11, 562 16. 6
MDD+ FF Pumping Capacity Surplus 26, 648 38. 4
Criteria 2: Peak Hour
Demands
Peak Hour Demand 8, 506 12. 2
PHD Pumping Capacity Surplus 29, 704 42. 8
Notes:
a) Firm pumping capacity reflects the capacity of the pumping station with the largest domestic pump offline.
b) Reflects MDD plus one high density residential ( 2, 000 gpm) fire and one industrial or heavy commercial fire ( 4, 000 gpm).
c) MDD with fire flow governs as the more stringent criteria. d) SSJID Turnout 2 was designed to pump directly to Tank 5 or BPS - 5, therefore it' s not accounted for in the total pumping capacity.

8. 2 Future Water System Evaluation
The following sections evaluate the City' s future pumping and storage capacity and requirements at buildout. These sections also describe the storage and pumping capacity that each future development will need to provide to meet the City Standards.

8. 2. 1 Water Supply Capacity
At buildout, the City' sfirm supply capacity is anticipated to increase because of reactivation of Well 9 and the future expansion of SSJID Turnout 2. The total supply pumping capacities at buildout is approximately 18, 760 gpm.

Future supply pumping requirements ( equal to total MDD) are 13, 075 gpm. Table 8- 4 shows the itemized projected Citywide pumping capacity availability and requirements. At buildout, the City is anticipated to have a supply pumping surplus of approximately 5, 685 gpm. eki environment
water 8-3
December 2024
EKI C20049. 01
288
Section 8

WATER SUPPLY, STORAGE, AND PUMPING CAPACITY EVALUATION
2024 WSMP Amendment
City of Lathrop
Table 8-4. Projected Water Supply Capacity
Available Supply
Capacity
Supply Component
SSJID Turnout 1 Capacity
Required or Available Firm Supply Capacity (a)
Existing Buddout
gpm gpm MGD
5, 210 7. 5 5, 210 7. 5
LAWTF Capacity ( b) 4, 150 6. 0 5,50 8. 0
SSJID Turnout 2 Capacity 4, 000 5. 8 8, 000 11. 5
Total Supply Capacity 13, 360 19. 2 18, 760 27. 0
Required Supply
Capacity
Maximum Day Demand 5,62 8. 0 13, 075 18. 8
Notes:
a) Firm supply capacity reflects the capacity of the supply source with the largest pump offline. b) LAWTF production capacity at buildout equals the firm capacity of Wells 6, 7, 8, and 9. Well 10 is not included because it is highest capacity well.

8.2. Water Storage Capacity
The City' s water storage capacity is anticipated to expand to support future development. Table 8- 5 shows the existing and required storage that each development area will need to provide in the future to meet the City' sstorage criteria for emergency and equalization storage.

River Islands already has plans to build an additional 3. 6 MG of storage at the existing Tank 5 site and plans to design two additional 1. 8 MG tanks ( 3. 6 MG total) to support the River Islands Phase 2 development. A 1. 0 MG storage tank at the former Well 21 site is also planned to provide additional storage capacity. Reactivation of Well 9 will increase the City' s groundwater credit to 6. 0 MG. Table 8-6 shows these planned storage projects can support the projected Citywide future storage needs. The City is anticipated to maintain a storage surplus of 2. 0 MG at buildout. eki environment
water 8- 4
December 2024
EKI C20049. 01
289
Section 8

WATER SUPPLY, STORAGE, AND PUMPING CAPACITY EVALUATION
2024 WSMP Amendment
City of Lathrop
Table 8-5. Projected Storage Requirements by Development Area Development Area
Projected Storage Requirement
Existing
MG) (a)
Buildout
Central Lathrop Specific Plan ( b) 0. 36 3. 01
Mossdale Landing 1. 05 1.4
Mossdale Landing East 0. 32 0. 39
Mossdale Landing West 0.0 0. 49
Mossdale Landing South 0.8 0. 20
River Islands 1. 36 7. 54
South Lathrop 0.4 0. 28
Lathrop Gateway 0.4 0. 46
Crossroads 0. 93 0. 98
Historic Lathrop 3. 88 4. 24
Sharpe Army Depot 0.1 0.9
Notes:
a) Storage requirement includes equalization storage ( 0. 25 x MDD) and emergency storage ( 0. 75 x MDD). b) Includes CLSP phase 1 and 2 developments.
c) Totals may not sum due to rounding.

Table 8-6. Projected Citywide Storage Requirements
Available Storage
Capacity
Planned
MG)
Storage Component
Existing Storage Capacity ( a)
Existing

7. 4
Buildout

7. 4
Groundwater Credit (b) 4. 5 6. 0
Storage Capacity ( c) 8. 2
Total Existing and Planned Storage Capacity 11. 9 21. 6 Required Storage
Capacity
MG)
Operational 2. 0 4. 7
Emergency 6. 0 14.

System Wide Fire Storage 0. 7 0. 7
Total Projected Required Storage Capacity 8. 7 19. 5
Notes:
a) Tank storage capacity includes total capacity of Tanks 1, 2, 3, 4, 5, 6, and the LAWTF Tank. The tank storage capacity does not include the tank at the SSJID turnout, which is not a City facility. b) Groundwater credit is calculated as the firm capacity of the wells with backup power ( i.e., with highest - capacity well with backup power out of service) over an 18 -hour period. This is equal to the 18 -hour maximum capacity of Wells 6, 7, 8, and 9 at buildout. Well 10 is not included because it is highest -capacity well with backup power.
c) Planned storage includes 1 MG for the planned tank at the Well 21 site, 3. 6 MG for Tanks 5B and 5C, and

3. 6 MG for the River Island Phase 2 tanks.
ek, environment
water 8- 5
December 2024
EKI C20049. 01
290
Section 8
WATER SUPPLY, STORAGE, AND PUMPING CAPACITY EVALUATION City of Lathrop 2024 WSMP Amendment

8. 2. 3 Peak Pumping Capacity
As with storage capacity, the City' s peak pumping capacity is anticipated to expand to support future development. Table 8-7 shows the Citywide required pumping capacities under MDD plus two simultaneous fire flows and PHD scenarios in the future to meet the City' s pumping requirement criteria.

River Islands has planned Tank 5 BPS expansion, which will provide an additional 4, 000 gpm firm pumping capacity and the planned phase 2 BPS is assumed to provide 8, 000 gpm firm pumping capacity. 19 The planned BPS at the previous Well 21 site is anticipated to provide 3, 000 gpm firm pumping capacity. Table 8- 7 shows these planned BPSs at buildout on top of the projected Citywide pumping capacity needs.

Table 8-7. Projected Citywide Pumping Requirements
Available or Required Capacity ( a)
Existing
gpm mgd
Buildout
gpm mgd
Available
Pumping
Capacity
SSJID Turnout 1 5, 210 7. 5 5, 210 7. 5
LAWTF Booster Station 6, 300 9. 1 6, 300 9. 1
BPS - 1 1, 050 1. 5 1, 050 1. 5
BPS -2 3, 000 4. 3 3, 000 4. 3
BPS - 3 4, 750 6. 8 4, 750 6. 8
BPS -4 4, 600 6. 4, 600 6.

BPS -5 ( b) 8, 000 11. 5 12, 000 17. 3
BPS - 6 5, 300 7. 6 5, 300 7. 6
Planned BPS at the former Well 21 site 3, 000 4. 3
Planned River Islands Phase II BPS 8, 000 11. 5
Total Available Firm Pumping Capacity 38, 210 55. 0 53, 210 76. 6 Criteria 1: Max
Day Plus Fire
Flow
MDD Plus Two Concurrent Fires ( c) 11, 562 16. 6 19, 075 27. 5 Max Day Plus Two Concurrent Fires
Pumping Capacity Surplus
26, 648 38. 4 34, 135 49. 2
Criteria 2: Peak
Hour Demands
PHD 8, 506 12. 2 19, 996 28. 8
Peak Hour Demand Pumping Capacity 29, 704 42. 8 33, 214 47. 8 Notes:
a) Firm pumping capacity reflects the capacity of the pumping station with the largest domestic pump offline. b) Firm pumping capacity at buildout from City of Lathrop Phase I Potable Water Booster Pump station and Storage Tank Expansion Plan at River Islands 100% Plans ( PACE, 2022). c) Value is equal to the MDD plus the fire flow criteria for one high density residential fire ( 2, 000 gpm) and one industrial fire ( 4, 000 gpm).
d) Total pumping capacity surplus or deficit reflects the most stringent criteria. Deficits will be made up by future booster pump stations.
e) SSJID Turnout 2 was designed to pump directly to Tank 5 or BPS -5 therefore it' s not accounted for in the total pumping capacity.
19 Based on 2022 BPS - 5 configurations.
eki environment
water 8- 6
December 2024
EKI C20049. 01
291
Section 9 2024 WSMP Amendment
RECOMMENDED CAPITAL IMPROVEMENT PROGRAM CHANGES City of Lathrop 9 RECOMMENDED CAPITAL IMPROVEMENT PROGRAM CHANGES
This section recommends modifications to the list of CIPs included in the 2019 WSMP and the City' s Fiscal Year ( FY) 2023 - 2025 Capital Improvement Program ( Lathrop, 2023). Table 9-1 summarizes CIPs from the 2019 WSMP and the City' s Capital Improvement Program and incorporates the modifications recommended herein. Figure 9- 1 shows an overview of the distribution system project locations and improvements. Each project is shown in detail in Appendix C. In addition to these CIPs, the analysis presented herein assumes that the development -related improvements identified in Section 7 will also be implemented.

Opinions of probable costs ( OPCs) presented below are conceptual level estimates, 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. OPCs for each project are escalated to December 2024 dollars based on an Engineering News Record ( ENR) Construction Cost Index ( CCI) of 13, 632 (20 -city average).

9. 1 Modifications to Water Supply CIPs
The following modifications to the City' s water supply CIPs are identified to reflect the discussion of water supply strategy in Section 5. 6. In addition to these CIPs, it is recommended that the City explore water transfer opportunities with regional water projects to increase the available supplies.

9. 1. Groundwater Treatment Improvements
The City will need treatment for all of its groundwater wells to meet the USEPA' s proposed PFAS MCLs, anticipated to be effective by 2026. As described in Section 5. 6.2, the City completed a feasibility study in 2022 for centralized PFAS treatment at the existing LAWTF. The project OPC for a 7, 000 gpm GAC treatment system was estimated to be $ 22 million, escalated to December 2024 dollars ( Carollo Engineers, 2022). The City currently has budgeted $ 25, 564, 010 for overall groundwater treatment improvements through FY 2026 (Lathrop, 2023).

9. 1. 2 Aquifer Storage and Recovery
As discussed in Section 5. 6.3, the City' ssupplies have historically been highly reliable. However, the City' s surface water supplies face uncertainties with implementation of the Bay -Delta Plan Amendment and new water quality regulations. The City should continue to monitor Bay -Delta Plan Amendment negotiations for the Stanislaus River. If the Bay -Delta Plan Amendment or a Voluntary Agreement with high cutbacks is implemented that significantly impacts the reliability of the SCWSP, an ASR project would boost the City' s dry year water supply and mitigate the impacts of severe droughts. Additionally, an ASR project would be capable of supplying water during water supply emergencies related to water quality concerns or treatment downtime.

Per the City' sfeasibility assessment, ASR wellfields are typically constructed in phases. To pursue the project, the City would construct a full- size ASR well with one or two monitoring wells, and conduct cycle testing to verify operational performance. During the next phase, additional ASR wells would be constructed and placed into operation ( Carollo Engineers, 2023).

The City' s 2023 assessment estimates that constructing the first ASR well for the City, including well construction and equipment costs, would cost $ 5. 6 million escalated to December 2024 dollars. The City' s current Capital Improvement Program includes $ 6. million for project design, construction, acceptance, and commission. EKI estimates a total project OPC at $ 9. 0 million considering a 60% markup for eki environment
water 9- 1
December 2024
EKI C20049. 01
292
Section 9
2024 WSMP Amendment
RECOMMENDED CAPITAL IMPROVEMENT PROGRAM CHANGES City of Lathrop construction contingency, design, construction management, permitting, and project implementation consistent with other CIPs.

9. 2 Modification to Water Distribution System CIPs
Due to the updated water demand projections evaluated herein, which are significantly lower than those included in the 2019 WSMP, the following projects are removed or modified from the list of the City' s existing CIPs and recommended CIPs in the 2019 WSMP:

The BPS -2 and BPS -3 Pipeline Replacement Projects are no longer necessary ( portion of PW 22- 22);
Well 21 WTF Phase 2 Improvements are no longer necessary, except for the construction of the 1 MG tank and BPS at the Well 21 location;
The Sadler Oak Transmission Improvement Project is no longer necessary; Multiple fire flow improvement projects are no longer necessary or have reduced in scale, including the E. Louise Avenue project ( PW 22- 21), Harlan Road project ( PW 22-2), Easy J Street Alley project near BPS -1 and Crossroads project; and
The I-5 crossing at Lathrop Road was originally anticipated to be completed by developers but is now incorporated as City CIP PW 25- 10 East Lathrop Water Distribution System Improvement project. The project connects the distribution system between Golden Valley Parkway and Old Harlan Road on Lathrop Road.

Modifications to the Harlan Road project ( PW 22-2) are discussed further in Section 9. 2. 1below.

In addition, the following projects recommended in the 2019 WSMP have been completed as of the date of this update:

LAWTF Transmission Improvement Project ( Louise Avenue 12" CIP) BPS -1 Pipeline Replacement Project
Old Harlan Road Fire Flow Improvement Project
One new CIP has been identified to address the fire flow deficiency identified on Murphy Parkway.

9. 2. 1 Harlan Road and South Harlan Road Fire Flow Improvement Project The hydraulic modeling results indicate the fire flow deficiencies at the intersection of Harlan Road and South Harlan Road can be addressed by the City' scurrent CIP PW 25- 10 (previously PW 22- 22), the Harlan Road Fire Flow Improvement Project, in a reduced scale.

The recommended scaled down project consists of:

Replacing approximately 1, 270 LF of existing 6 -inch mains on Harlan Road between Lathrop Road and Shilling Avenue20;
Replacing approximately 600 LF of existing 2 -inch mains on Harlan Road between Shilling Avenue and Warren Avenue with a new 8 -inch main; and
Installing approximately 490 LF of 8 -inch main along Harlan Road to connect to the existing mains at the intersection of Warren Avenue and Harlan Road.
20 This existing pipeline section has been identified with inconsistent diameters of 6" and 8" across various record documents. Further verification may be required to confirm the actual pipe size. ek, environment
water 9- 2
December 2024
EKI C20049. 01
293
Section 9
2024 WSMP Amendment
RECOMMENDED CAPITAL IMPROVEMENT PROGRAM CHANGES City of Lathrop Installing approximately 70 LF of 8 -inch main connecting new 8 -inch mains on Harlan Road and Old Harlan Road at the intersection of Harlan Road and Shilling Avenue.

To eliminate dead- end pipes and improve system resilience, EKI recommends retaining the original project scope to install approximately 580 LF 12 -inch main connecting the 12 -inch main on South Harlan Road to the new 8 -inch main on Harlan Road.

The total project OPC is approximately $ 1,90, 000.

9. 2. Murphy Parkway Fire Flow Loop to Harlan Road
The City' s existing CIP PW 24- 11 includes installing a new 12 -inch water main from Murphy Parkway across to Harlan Road to loop the dead- end of the 10 -inch water main on Murphy Parkway. The loop is currently completed by an old private 8 -inch main and not included in the City' s hydraulic model. The hydraulic modeling results indicate that replacing the private 8 -inch main with a new 8 -inch line can address the fire flow deficiency identified on Murphy Parkway and increase system reliability. The updated OPC is approximately $ 180, 00.

9. 2. 3 East J Street Alley Residential Fire Flow Improvement Project This project updates BPS -1 Pipeline Replacement and Residential Fire Flow Improvement Project recommended in the 2019 WSMP due to completion of improvements of the BPS -1 discharge main and distribution mains on J Street and Avon Street.

The recommended East J Street Alley Residential Fire Flow Improvement Project addresses existing fire flow deficiencies along the residential alley between 5th and 6th Streets and eliminates the dead- end of the 6" pipe near H Street for higher system resilience. This project consists of:

Replacing approximately 1, 020 LF of existing 4 -inch mains in the alley between 5th and 6th Streets with a new 8 -inch main; and
Installing an approximately 80- LF 6 -inch connection between the existing 10 -inch main on East H Street and the existing 6 -inch main in the alley between 5th and 6th Streets.

Total project OPC is $ 400, 00.

9. 2.4 Lathrop Transmission Main Improvement Project
The City' s existing CIP PW 25- 10 includes installing approximately 1, 450 LF of new 8 -inch transmission main connection between the existing 8 -inch dead- end mains on Lathrop Road on both sides of Interstate Highway 5. The total project OPC is approximately $ 570, 00. eki environment
water 9-3
December 2024
EKI C20049. 01
294
Section 9

RECOMMENDED CAPITAL IMPROVEMENT PROGRAM CHANGES
2024 WSMP Amendment
City of Lathrop
Table 9-1. Summary of Recommended Water System Capital Improvement Projects Project #
Water Supply Improvements
Time Frame
Addresses
Total Project OPC
Project ( a) Fire Flow
b) d
Deficiency (
c )( )
WS 1
Well 10 Testing, Analysis and
Modifications ( PW 22- 37) (e)
Existing 844, 527
WS -2
Booster Pump Stations Upgrade
Project ( PW 24- 10) (e)
Existing 800, 00
WS -3
Groundwater Treatment
Improvements ( PW 20- 16) (e)
Existing 25, 564, 010
WS 4
SSJID Turnout 1 Emergency Backup
Power (f)
Buildout 930, 00
WS - 5 Tank and BPS at the Well 21 Site ( g) Buildout 5, 640, 000 WS -6 SSJID SCWSP Phase 2 ( f) Buildout 28,80, 000
WS -7 SSJID Turnout 2 Expansion ( f) Buildout 4,90, 000 WS -8
Aquifer Storage and Recovery
PW 22- 36) (d) (e)
Buildout 9, 000,00
TOTAL WATER SUPPLY IMPROVEMENTS OPC $ 75, 550, 000
Water Distribution System Improvements
WD -1
East J Street Alley Residential Fire
Flow Improvement Project ( PW 25-
10)
Existing Yes 400, 00
WD 2
Harlan Road Fire Flow Improvement
Project ( PW 25- 10) (e) (h) (i)
Existing Yes 1,90, 000
WD -3
Northern McKinley Industrial Area
Fire Flow Improvement Project
Existing Yes h)
WD -4
Murphy Parkway Fire Flow
Improvement Project
PW 24- 11) (e) (j)
Existing Yes 180, 00
WD -5
Lathrop Transmission Main
Improvement Project ( PW 25- 10) Existing Yes 570, 00
WD -6
Lathrop Water Main and
Lateral Upgrade Project ( PW 24- 12)
e)
Existing Yes 120, 00
TOTAL WATER DISTRIBUTION SYSTEM IMPROVEMENTS OPC 2, 460, 000 Notes:
a) Project information is obtained from Table 9- 1 of the 2019 WSMP with their costs escalated to December 2024 dollars, and includes modifications recommended in Sections 9. 1 and 9. 2. b) Time frame refers to when projects are identified to be required. c) Costs shown are presented in December 2024 dollars based on an ENR CCI of 13, 632. 41 (20 -city average), with totals rounded to the nearest $10, 000, except for projects called out in footnote e).
d) Costs include mark- ups equal to 60% for construction contingency ( 25%), design ( 10%), construction management ( 10%), permitting ( 10%), and Project Implementation ( 5%). ekienvironment water 9- 4
December 2024
EKI C20049. 01
295
Section 9 2024 WSMP Amendment
RECOMMENDED CAPITAL IMPROVEMENT PROGRAM CHANGES City of Lathrop Improvements and associated costs have been carried over from the City of Lathrop Capital Improvement Programs Fiscal Years 2023 - 2025 ( City of Lathrop, 2023).

Construction costs for improvements have been carried over from estimates in the 2013 Draft Water Master Plan, escalated to December 2024 dollars.

Construction costs for Tank and BPS at the former Well 21 site reflect the engineer' sestimate prepared by H2O Urban Solutions in July 2017, escalated to December 2024 dollars.

This project will be conditioned for private development to complete.

For planning purpose, cost estimated shown in the table was based on 6 -inch for existing water mains along Old Harlan Road between Shilling Avenue and Lathrop Road, City to verify the actual size since inconsistent pipe diameters observed in available documentation.

Costs were updated to reflect reduced project scale as recommended in Section 9. 1. eki environment
water 9- 5
December 2024
EKI C20049. 01
296
Section 10

REFERENCES
2024 WSMP Amendment
City of Lathrop
10 REFERENCES
Black and Veatch, 2002. South San Joaquin Irrigation District South County Water Supply Program Basis of Design Report, May 2002.

California DOF, 2007. E- 4 Revised Historical City, County and State Population Estimates, 1991- 2000, with 1990 and 2000 Census Counts, August 2007.

California DOF, 2012. E- 4 Population Estimates for Cities, Counties, and the State, 2001- 2010, with 2000 2010 Census Counts, November 2012.

California DOF, 2022. E- 4 Population Estimates for Cities, Counties, and the State, 2011-020, with 2010 Census Benchmark, May 2022.

California DOF, 2023. E- 5 Population and Housing Estimates for Cities, Counties, and the State, January 2021-023, with 2020 Benchmark, May 2023.

DWR, 2021. California' sGround Water Bulletin 118 - Update 2020, California Department of Water Resources, November 2021.

Carollo Engineers, 2022. Technical Memorandum 1: PFAS Centralized Treatment Feasibility Study. Carollo Engineers, June 2022.

Carollo Engineers, 2023. City of Lathrop Aquifer Storage Recovery Feasibility Assessment, final March 2023.

EKI, 2019a. Water System Master Plan, City of Lathrop Integrated Water Resources Master Plan Update, final December 2019.

EKI, 2019b. Wastewater System Master Plan, City of Lathrop Integrated Water Resources Master Plan Update, final December 2019.

EKI, 2019c. Recycled Water System Master Plan, City of Lathrop Integrated Water Resources Master Plan Update, final December 2019.

EKI, 2020. Technical Memorandum: Alternative Evaluation for Use of Groundwater with Detections of Per - and Polyfluoroalkyl Substances, draft 6 March 2020.

EKI, 2021a. 2020 Urban Water Management Plan for the City of Lathrop, June 2021. Available at:

EKI, 2021b.
https:// www. ci. lathrop. ca. us/ publicworks/ page/ urban- water- management- plan 2020 Urban Water Management Plan for South San Joaquin Irrigation District. Available at:
https:// www. ssjid. com/ wp- content/ uploads/ 2020 UWMP SSJID. pdf Lathrop, 2016. Municipal Service Review and Sphere of Influence Plan, 14 April 2016.

Lathrop, 2022a. City of Lathrop General Plan, August 2022. Available at: https:// lathrop. generalplan. org/ Lathrop, 2022b. River Islands Phase 2 Project, https:// www. ci. lathrop. ca. us/ planning/ page/ river- islandsphase- 2- project Lathrop, 2022c. City of Lathrop Department of Public Works Design & Construction Standards. Available at: https:// www. ci. lathrop. ca. us/ publicworks/ page/ design- construction- standards Lathrop, 2023. Capital Improvement Programs Fiscal Years 2023-025. Available at:
https:// www. ci. lathrop. ca. us/ finance/ page/ budget OID and SSJID, 2019. Stanislaus River Basin Proposal, dated 1 March 2019.

RBF, 2009. Water Supply Study, prepared for the City of Lathrop, January 2009. eki environment
water 10-
December 2024
EKI C20049. 01
297
Section 10

REFERENCES
2024 WSMP Amendment
City of Lathrop
SGI, 2008. Technical Memorandum for the Groundwater Model Update, City of Lathrop Water Supply Study. Source Group, Inc., 25 April 2008.

SWRCB, 2022. Revised Notice of Preparation and California Environmental Quality Act Scoping Meeting, dated 8 August 2022.

UNICO Engineering, 2015. Technical Memorandum to City of Lathrop, Evaluate Uranium Levels Near the Vicinity of Well 21, 19 March 2015.

U. S. Census, 2023. QuickFacts, Lathrop city, California, https:// www. census. Rov/ quickfacts/ lathropcitycalifornia, accessed December 15, 2023.

U. S. EPA, 2023. EPA' s PFAS Strategic Roadmap: Second Annual Progress Report, December 2023. Available at:
2023508v2. pdf
https:// www. epa. gov/ system/ files/ documents/ 2023- 1/ epas- pf- strategic- roadmap- decWoodard & Curran, 2020. River Islands Phase 2 Development Water Supply Assessment, dated September 2020.
ek, environment
water 10- 2
December 2024
EKI C20049. 01
298
2024 WSMP Amendment
City of Lathrop

APPENDIX A
Water Demand Factor Evaluation
ekienvironment water
299
Appendix A

WATER DEMAND FACTOR EVALUATION
2024 WSMP Amendment
City of Lathrop
A. WATER DEMAND FACTOR EVALUATION
EKI evaluated the City' s billing data to develop representative unit water use factors for each anticipated land use category. The water use factors assign a unit volume of water demand to each acre of commercial, industrial, and institutional ( CII) development ( gpd/ acre) or an individual dwelling unit ( gpd/ du). The factors described herein update those developed by EKI in 2020, which were included as part of the City' s 2020 Urban Water Management Plan ( UWMP).

The methodology utilized to verify and update the City' s water demand factors is summarized in
this section.

As discussed in Section 4. 1, the City' s water use has fluctuated over the past several years, responding to changing economic and drought conditions. During the extended drought of 2014- 2017, the City' s
water production decreased dramatically due to the voluntary and mandatory water conservation efforts that were implemented by the City' s water customers. Water
production rebounded between 2017 and 2020 as water use restrictions were lifted and new development projects were constructed, however, is again affected by the recent drought of 2021-022. The City' s water demand factors were last updated in July 2020 based on post - drought water use between 2017 and 2019. The analysis herein verifies the 2020 water demand factors against water use trends through 2021.

Based on these data, 2022 was selected as the " representative year" (i.e., it reflects the latest water use behavioral changes and moderate drought conditions). The total production and per capita water use in 2022 are slightly below the average values over the past 10 years. This level of optimism is appropriate for future projections, given that this number accounts for both the water use behavioral changes and construction of new water -efficient development along with retrofits of existing properties, both of which significantly impacted water use.

A. 1 Residential Water Use Factors
Development of residential water use factors focused on quantifying water use in homes within the City, as a whole and by development area. Historical residential water use was evaluated on a parcel - by -parcel basis based on the City' s water billing data. Annual water use was extracted for residential accounts with complete billing records between 2017 and 2021.

To simplify the evaluation, various development area -specific zoning classes were grouped into one of three categories Low Density Residential ( LDR), Medium Density Residential ( MDR), and High Density Residential (HDR). LDR accounts for Single - Family accounts with lot sizes larger than 4, 000 square feet, while MDR includes Multi -Family accounts and Single - Family accounts with lot sizes equal to or less than 4, 000 square feet. 1 HDR exclusively represents apartment land use. 1 Account type extracted from the City' s potable water billing data. Lot size information based on San Joaquin County Assessor data.
eki environment
water A- 1
December 2024
EKI C20049. 01
300
Appendix A

WATER DEMAND FACTOR EVALUATION
2024 WSMP Amendment
City of Lathrop
Figure A- 1 shows which individual parcels fell into each land use category, according to the San Joaquin County Assessor parcel data. Only accounts with full year of billing data in each year were considered as qualified data for the LDR and MDR water use factor analysis. Figure A- 2 shows the breakdown of total qualified residential accounts in the LDR and MDR categories between 2017 and 2021 by development area. HDR water use were only available between November 2022 and May 2023 with construction and occupation of the Towne Centre Apartment and were evaluated separately.
ekienvironment water A- 2
December 2024
EKI C20049. 01
301
fL, egendSphere of Influence
Development Areas
Central Lathrop
QCrossroads
L_j
Historic Lathrop Infill and Other Developments
0Lathrop Gateway
Mossdale Landing
Mossdale Landing East
E.]
Mossdale Landing West
u] Mossdale Landing South
ORiver Islands
Sharpe Army Depot
South Lathrop
Land Use Categories
Low Density Residential
Medium Density Residential
High Density Residential
Notes

1. All locations are approximate.

2. Includes all residential accounts with at least one full year of billing data.

Sources

1. Aerial photograph provided by ESRI' s ArcGIS Online, 13 November 2024.

N
4, 000 8, 000
Scale in
Residential Land Use Categories
yMter System Master Plan Amendment
Day of Lathrop
Lathrop, CA
December 2024 ekenvironment I & C20009.
water
01 Figure A- 1
302
Appendix A

WATER DEMAND FACTOR EVALUATION
2024 WSMP Amendment
City of Lathrop
Number
of
Accounts
Figure A- 2 Qualified Low Density and Medium Density Residential Accounts Qualified Low Density Residential Accounts
3, 500
3, 000
2, 500
2, 000
1, 500
1, 000
500
0 316
2017
325
2018
285
2019
Year
314
2020
304
2021
Historic Lathrop Infill Mossdale Landing Mossdale Landing East • Mossdale Landing South • River Islands 500
450
400
350
0 300
c
250
N
12 200
3 Z
150
100
50 0
43 Qualified Medium Density Residential Accounts
42 41
2017 2018 2019
Year
w Historic Lathrop Infill Mossdale Landing Mossdale Landing East • Mossdale Landing South • River Islands 2020
43 2021
eki environment
water A- 4
303
Appendix A

WATER DEMAND FACTOR EVALUATION
2024 WSMP Amendment
City of Lathrop
The available data were further evaluated to assess the extent to which each development area had unique water use patterns. Figure A- 3
presents the average per unit water use between 2017
and 2021 by land use category and development area. These figures indicate that ( 1) while certain patterns are apparent, residential units in each development area, broken down by the selected land use categories, used similar amounts of water per dwelling unit annually, and exhibited similar water use trends during this period; and ( 2) the water use in medium density residential units in the River Islands area are consistently lower than those in the other parts of the City. This confirms the methodology of developing a specific set of factors based on River Islands residential water use for the future water demand projection in this area, and " City- wide" factors to project residential uses for the rest of the City.

As Figure A- 3 shows, though the average water use varied slightly year by year, no significant change in Low Density Residential and Medium Density Residential water use pattern has been identified between 2020 and 2022 compared to 2017 through 2019. As such, the City' s 2020 water demand factors for Low Density Residential and Medium Density Residential categories are confirmed to be ( 1) 330 gpd/ duand 250 gpd/ du for City- wide low and medium - density residential units, respectively, and ( 2) 315 gpd/ du and 235 gpd/ dufor River Islands low and medium density residential units, respectively. A uniform, City- wide high density residential water use factor of 170 gpd/ du was determined by water use in the Towne Centre Apartments in the Mossdale Landing area, since no water use from high density water units are available from River Islands as of the date of this report.
ekienvironment water A- 5
December 2024
EKI C20049. 01
304
Appendix A

WATER DEMAND FACTOR EVALUATION
2024 WSMP Amendment
City of Lathrop
Figure A- 3 Low and Medium Density Residential Water Demand Factor Evaluation Per Unit Low Density Residential Water Use
a
450
O. 400
350
c
t
300
250
a
0 200
a
3 150
u • 100
a
50 d
b.° 0
Average
Water Consumption
Per Dwelling
Unit (
gpd/ du)
350
300
250
200
150
100
50 0
2017
Historic Lathrop Infill
327
2018 2019
Year
Mossdale Landing
Mossdale Landing South Mil River Islands
2 2017
351
2020
339
2021
Mossdale Landing East
Low Density Average
Per Unit Medium Density Residential Water Use
Historic Lathrop Infill
Mossdale Landing South
249
2018 2019 2020
Year
toroo Mossdale Landing
moo River Islands
IND
2021
Mossdale Landing East
Medium Density Average
e
environment
water A- 6
December 2024
EKI C20049. 01
305
Appendix A

WATER DEMAND FACTOR EVALUATION
2024 WSMP Amendment
City of Lathrop
A. 2 CII Water Use Factors
Per acre water use factors for commercial, industrial, parks/ irrigation, and schools/ institutions were updated based on the City' s billing data from 2017 to 2021. For each CII land use, the total water use each year, including sub - metered irrigation accounts, was divided by the total acreage to determine water use factors. Acreages were calculated by cross- referencing the City' s billing database with the San Joaquin County parcel database. Land use categories were extracted from the City' s billing data account types for each customer.

As part of this update, City staff identified inconsistencies within the City' s billing data account types and reclassified certain CII users, which significantly altered the results compared to the 2020 water demand factors analysis. Figure A- 4 shows which individual parcels fell into each land use category, as confirmed by City staff. Figure A- 5 presents the historical average per acre water use and total area evaluated each year for commercial and industrial land uses.

General commercial and industrial water use factors were evaluated based on the average commercial and industrial water uses between 2017 and 2021, including on -parcel irrigation, respectively. The water use factor was determined to be 1, 550 gpd/ ac for Commercial land uses.

The commercial water demand factor increased significantly compared to the 2020 factor of 860 gpd/ acre, likely due to that a significant portion of commercial accounts were corrected as industrial, government, or park land uses. The average water use by industrial water users between 2017 and 2021 was 1,32 gpd/ ac, generally consistent with the 1, 200 gpd/ ac water use factor for Industrial land uses.

The water use factor for parks and landscape irrigation was quantified based on historical water use data for the following parks:

Apolinar Sangalang Park
Armstrong Park
Crescent Park
Crystal Cove Park
Green Belt Park
Historical Marker
Homsen Park
Islanders Field
Lathrop Dog Park
Lathrop Generations Center
Lathrop Generations Fitness Park
Lathrop Squares
Leland and Jane Stanford Park
Libby Lane Park
Manuel Valverde Park
eki environment
water A- 7
Michael Vega Park
Milestone Park
Mossdale Crossing Regional Park
Mossdale Landing Community Park
Park West
River Park North
River Park South
Somerston Park
The Commons at Mossdale Landing
The Green at Mossdale Landing
Tidewater Park
Woodfield Park
William S. Moss Park
Other unnamed community park in
River Islands, Mossdale, and CLSP
December 2024
EKI C20049. 01
306
L, egend
Sphere of Influence
Development Areas
Central Lathrop
QCrossroads
U Historic Lathrop Inn and Other Developments
Lathrop Gateway
QMossdale Landing
Mossdale Landing East
J Mossdale Landing West
Mossdale Landing South
River Islands
Sharpe Army Depot
South Lathrop
Land Use Categories
Commercial
Industrial
sr Park
School
IMP Government
Notes

1. All locations are approximate.

2. Includes all residential accounts with at least one full year of billing data.

Sources

1. Aenal photograph provided by ESRI' s ArcGIS Online,
13 November 2020.

N o
A
eki
a O00 6, 000
Scale In Fee)
CII Land Use Categories
Water System Mester Plan Amendment
CM of Lemrop
Lathrop, CA
024
environment
December
C20049. 01.01
water Figure A- 5
307
Appendix A

WATER DEMAND FACTOR EVALUATION
2024 WSMP Amendment
City of Lathrop
2, 000
1, 800
OD 1, 600
a
1, 400
c 1, 200
E 1, 000
0 • 800
v
600
400
a • 200
0 1, 000
900
800
700
600
v 500
400
300
200
100
eki
0 969
Figure A- 5 Commercial Water Demand Factor Evaluation
1, 770
Commercial Water Demand Factors
1, 362
2017 2018
Industrial
1, 380
1,75
1, 309
1, 540
1, 074
1, cg2
2019 2020 2021
Year
so Commercial
Commercial and Industrial Land Use Acreage Included in Analysis 876
118
2017
environment
water
872
2018
El Industrial
856
2019
A- 9
Year
896
2020
WI Commercial
872
2021
December 2024
EKI C20049. 01
308
Appendix A 2024 WSMP Amendment
WATER DEMAND FACTOR EVALUATION City of Lathrop
Historical water use for parks evaluated herein presents total water use, inclusive of both potable water and recycled water uses, to determine the total irrigational demand of park acreages.

Figure A- 6 shows that park water use increased between 2017 and 2021, likely due to construction of new parks in the new development areas and water use rebound post the 2014 and 2017 drought. Irrigation water demand was suppressed in 2019 due to insufficient water main pressure when the Louise Avenue Water Treatment Facility ( LAWTF) was offline. The average park water use from 2017 to 2021 excluding 2019 was approximately 2, 383 gpd/ ac, generally consistent with the water use factor for Parks/ Irrigation at 2, 450 gpd/ ac.

Historical water use data was reviewed for the following schools and City services for the Schools/ Institutional land use category: 2
Joseph Widmer Jr. Elementary School
Lathrop Elementary School
Lathrop High School
Mossdale Elementary School
NextGeneration STEAM Academy
one. Lathrop
River Islands Technology Academy
Other City institutional uses including fire stations, City Hall, and post offices.

Figure A- 6 shows the schools/ institutional water use has been generally consistent over the past five years and averaged at 1, 322 gpd/ ac, which is generally consistent with the water use factor for Schools/ Institutional at 1, 500 gpd/ ac.
2 Water use in 2020 from the NextGeneration STEAM Academy and River Islands Technology Academy were excluded from analysis due to irregular water billing data. eki environment
water A- 10
December 2024
EKI C20049. 01
309
Appendix A

WATER DEMAND FACTOR EVALUATION
2024 WSMP Amendment
City of Lathrop
Figure A- 6 Park and School Water Demand Factor Evaluation 3, 000
m
to 2, 500
2, 128
V
Q
a`, :::
a
c
O
d,.

E
O • 1, 000
a
M
Q 0
140
120
100
80 t) 60
40 20
0 2017
119
2017
ek,1 & water
2018
Park and School Unit Water Demand
2, 095
2018
Park
2019
Year
School
2, 617
2020
Park and School Land Use Acreage Included in Analysis
119
113 — 113
119
2019
Year
DPark I2 School
A- 11
120
2020
2, 695
2021
129
2021
December 2024
EKI C20049. 01
310
Appendix A

WATER DEMAND FACTOR EVALUATION
2024 WSMP Amendment
City of Lathrop
A. 3 Summary of Water Use Factors
Based on the information presented above, Table A- 1 summarizes the water use factors developed for the 2023 IWRMP Amendment.

Table A- 1. Updated 2022 Water Use Factors
Land Use Category
Low Density Residential 330
Updated
City- wide
Potable Water
gpd/ du
Use Factors
River
315
a)
Islands
gpd/ du
Medium Density Residential 250 gpd/ du 235 gpd/ du
High Density Residential 170 gpd/ du
Commercial 1, 550 gpd/ ac
Industrial 1, 200 gpd/ ac
Parks / Public Landscaping 2, 450 gpd/ ac
Schools / Institutional 1, 250 gpd/ ac
ekenvironment ki & water A- 12
December 2024
EKI C20049. 01
311
2024 WSMP Amendment
City of Lathrop

APPENDIX B
Recommended CIP Details
eki environment
water
312
6"
12"
8"
12 BPS -1 Tank
Thomsen Rd.
6"
12"
12\ WSMP
Ma
Legend
Sphere of Influence
Existing Pipe
8" PVC Inch -Diameter and Pipe Material
Abbreviations
PVC = polyvinyl chloride
Replacement Pipe, Inches
8 New Pipe, Inches
6 Notes

1. All locations are approximate.

Sources

1. Aerial photograph provided by ESRI' sArcGIS Online, obtained 13 November 2024.
0 375 750
Feet
East J Street Alley Residential
Fire Flow Improvement Project
Water System Master Plan Amendment
City of Lathrop
December 2024
e
environment EKI C20049. 01
I & water Figure B- 1
313
Legend
f.III"
049\ Maps\ 2023 1\ WSMP
Maps
Orioinal. aprx
U
X

MI MI MI
Sphere of Influence
Existing Pipe
Future Pipe
8" PVC Inch -Diameter and Pipe Material
Abbreviations
PVC = polyvinyl chloride
Notes

1. All locations are approximate.

Replacement Pipe, Inches
8 New Pipe, Inches
8 12
Sources

1. Aerial photograph provided by ESRI' sArcGIS Online, obtained 13 November 2024.
ti 0 425 850
Feet
Old Harlan Road and South Harlan Road
Fire Flow Improvement Project
eki environment
water Figure B- 2
Water System Master Plan Amendment
City of Lathrop
December 2024
EKI C20049. 01
314
WSMP 12\
MaDS
a
ath:

X_\ C20040\ Maps 20
12 12"
12" 12"
12"
12"
Legend
Sphere of Influence
Existing Pipe
8" PVC Inch - Diameter and Pipe Material
Abbreviations
PVC = polyvinyl chloride
Notes

1. All locations are approximate.

Replacement Pipe, Inches
12 New Pipe, Inches
12 Sources

1. Aerial photograph provided by ESRI' sArcGIS Online, obtained 13 November 2024.
450 900
Feet
Northern McKinley Avenue Industrial
Area Fire Flow Improvement Project
eki
Water System Master Plan Amendment
City of Lathrop
December 2024
environment EKI C20049. 01
water Figure B- 3
315
Legend
LM

MI MI MI
8" PVC
0 n
2 Sphere of Influence
Existing Pipe
Future Pipe
Inch -Diameter and Pipe Material
Abbreviations
PVC = polyvinyl chloride
Notes

1. All locations are approximate.

New Pipe, Inches
8 Sources

1. Aerial photograph provided by ESRI' s ArcGIS Online, obtained 14 November 2024.
0 425 850
Feet
Murphy Parkway
Fire Flow Improvement Project
Water System Master Plan Amendment
City of Lathrop
December 2024
e1( environment EKIC20049. 01
water Figure B- 4
316
0 Co
C
0 O
Maos\ 2023 t2\ WSMP
Ma
N
V
X
Legend
Sphere of Influence
Existing Pipe
8" PVC Inch - Diameter and Pipe Material
Abbreviations
PVC = polyvinyl chloride
Notes

1. All locations are approximate.

New Pipe, Inches
8 Sources

1. Aerial photograph provided by ESRI' sArcGIS Online, obtained 14 November 2024.
0 150 300
Feet
Lathrop Road Transmission Main
Improvement Project
eki
Water System Master Plan Amendment
City of Lathrop
December 2024
environment EKI C20049. 01
water Figure B- 5
317

ATTACHMENT D
eki environment
water
2024 WASTEWATER SYSTEM MASTER PLAN

AMENDMENT
City of Lathrop
December 2024
EKI C20049. 02
EKI ENVIRONMENT & WATER, INC. 2001
www. ekiconsult. com
Junipero Serra Blvd, Suite 300 • Daly City, CA 94014
318
eki environment
water
2024 Wastewater System Master Plan Amendment
City of Lathrop
December 2024
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. 02
Jonathan Sutter, P. E.

Project Manager/ Supervising Engineer
A) cotl
Tina Wang, P. E.

Assistant Project Manager/ Associate Engineer
Chris Pittner, P. E.

Project Engineer
319
2024 WWSMP Amendment
City of Lathrop
2024 Wastewater System Master Plan Amendment
City of Lathrop

TABLE OF CONTENTS
1 INTRODUCTION 1-

1. Project Background 1-

1. 2 Scope of Work 1-

1. 3 Report Organization 1-
2 STUDY AND SERVICE AREAS 2-3

2. 1 City Limits, Sphere of Influence, and Service Boundaries 2-3

2. Specific Plans and Large Planned Unit Development 2- 3

2. 3 Current and Projected Population 2-9
3 CITY' SEXISTING WASTEWATER INFRASTRUCTURE 3-1

3. 1 Wastewater Collection 3-1

3. 1. Gravity System 3- 1

3. 1. 2 Pump Stations and Force Mains 3-5

3. 1. Collection System Intertie 3-5

3. 1. 4 Major Collection System Improvements Completed Since 2019 3-5

3. 2 Wastewater Treatment 3-8

3. 2. 1 Manteca Water Quality Control Facility 3-8

3. 2. Lathrop Consolidated Treatment Facility 3-8
4 EXISTING AND FUTURE WASTEWATER GENERATION 4-1

4. 1 Current and Historical Wastewater Flow 4-1

4. 2 Wastewater Generation Projections 4-5

4. 2.1 Existing Wastewater Generation 4-5

4. 2. Wastewater Generation Associated with Planned Development 4-5

4.2. 3 Total Projected Wastewater Generation 4-5

4. 3 Wastewater Peaking Factors 4-9
5 WASTEWATER TREATMENT CAPACITY ASSESSMENT 5-1

5. 1 Wastewater Treatment Capacity Assessment 5- 1

5. 2 Impacts of Wastewater Strength on Treatment Capacity 5-

5. 2. 1 Manteca Water Quality Control Facility 5-

5.2. Lathrop Consolidated Treatment Facility 5-
6 COLLECTION SYSTEM PERFORMANCE AND DESIGN CRITERIA 6- 1

6. 1 Capacity Criteria 6- 1
eki environment
water
December 2024
EKI C20049. 02
320
2024 WWSMP Amendment
City of Lathrop

6. 2 Minimum Velocity and Slope Criteria 6-1
7 HYDRAULIC ASSESSMENT OF THE COLLECTION SYSTEM 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 Update 7- 1

7. 3 Sewer System Hydraulic Modeling Scenarios 7-2

7. 4 Collection System Hydraulic Evaluation 7- 5

7. 5 Force Main and Pump Station Capacity Evaluation 7-8 8 CAPITAL IMPROVEMENT PROGRAM CHANGES TO THE 2019 WWSMP 8-1

8. 1 Modifications to Wastewater Treatment CIPs 8-1

8. 1. Manteca Interim Improvements 8- 1

8. 1. 2 Lathrop CTF Phase 3 Expansion 8- 1

8. 2 Modification to Collection System CIPs 8-2
9 REFERENCES 9- 1
ek, environment
water
ii
December 2024
EKI C20049. 02
321
2024 WWSMP Amendment
City of Lathrop
TABLES
Table 2-1. City of Lathrop Development Projections by Development Area 2-7 Table 2-. Historical City of Lathrop Population 2- 10
Table 2-3. Current and Projected City of Lathrop Population 2- 11 Table 3-1. Collection System Inventory 3-4
Table 3-2. Summary of Wastewater Pump Station Characteristics 3-6 Table 3-. Wastewater Capacity Allocation at MWQCF 3-8
Table 4-1. Current and Historical Wastewater AAF and Per Capita AAF 4-2 Table 4-2. Current and Historical ADWF and Per Capita ADWF 4-3 Table 4-3. Wastewater Flow Factors 4-5
Table 4-. Projected New Wastewater Flow by Development Area 4-6 Table 4-5. Existing and Future Wastewater Flow by Development Area 4-8 Table 5-1. Projected Wastewater Flow and Treatment Capacity at MWQCF 5-2 Table 5-2. Projected Wastewater Flow and Treatment Capacity at Lathrop CTF 5- 3 Table 5-3. Projected Wastewater Flow and Treatment Capacity, Citywide 5-4 Table 6-1. Minimum Gravity Main Slopes 6-1
Table 7-1. Peak Wet Weather Flow at Pump Stations 7-3
Table 7-2. Summary of Collection System Capacity Deficiencies 7-5 Table 7-3. Force Main Hydraulic Analysis Results 7-9
Table 7-4. Summary of Hydraulic Capacity Analysis for Pump Stations 7- 10 Table 8-1. Summary of Capital Improvement Projects 8-3

FIGURES
Figure 2-1. City of Lathrop Municipal Boundaries and Development Areas 2-6 Figure 2-. Historical and Projected City of Lathrop Population 2- 11 Figure 3-1. City' s Wastewater Infrastructure 3-2
Figure 3-2. City' s
Wastewater Pump Station Drainage Areas 3-
Figure 3-. City' s Wastewater Collection System Schematic 3-7 Figure 4-1. Current and Historical Wastewater Flow by Collection System 4- Figure 4-2. Current and Historical Per Capita Wastewater Flow 4- Figure 4-3. Average Dry Weather Flow and Peaking Factors 4-9 Figure 5-1. Projected Wastewater Flow and Treatment Capacity at MWQCF 5- 2 Figure 5-2. Projected Wastewater Flow and Treatment Capacity at Lathrop CTF 5-3 Figure 5-3. Projected Wastewater Flow and Treatment Capacity, Citywide 5- 4 eki environment
water
iii
December 2024
EKI C20049. 02
322
2024 WWSMP Amendment
City of Lathrop
Figure 7-1. Modeling Scenarios 7-4
Figure 7-2. Existing Collection System Capacity Deficiencies 7-6 Figure 7-3. Buildout Collection System Capacity Deficiencies 7- Figure 8-1. Recommended Collection System Improvement Projects 8-4

APPENDICES
Appendix A
Appendix B
Appendix C
Appendix D
Wastewater Generation Factor Evaluation
Wastewater Peaking Factor Evaluation
Summary of Monitoring Results from Evaluation of Biochemical Oxygen Demand Contribution to Manteca Water Quality Control Facility
Recommended CIP Details

APPENDIX D FIGURES
Figure D- 1. Stonebridge Gravity Main Replacement and Parallel Force Main Project Figure D- 2. Woodfield West Deficiency Project - Alternative A Figure D- 3. Woodfield West Deficiency Project - Alternative B Figure D- 4. J Street Gravity Main Replacement Project
Figure D- 5. Easy Court/ O Street Gravity Main Replacement Project ekienvironment water
iv
December 2024
EKI C20049. 02
323
2024 WWSMP Amendment
City of Lathrop

LIST OF ABBREVIATIONS
AAF Average Annual Flow
AAFES Army & Air Force Exchange Services
ac acre
ADWF Average Dry Weather Flow
AOI Area of Interest
BSF Base Sanitary Flow
BOD Biological Oxygen Demand
CCI Construction Cost Index
CII Commercial, Industrial, and Institutional
CIP Capital Improvement Projects
City City of Lathrop
CLSP Central Lathrop Specific Plan
d/ D depth to Diameter
Depot Sharpe Army Depot
DOF Department of Finance
du dwelling unit
EKI EKI Environment & Water, Inc.

ENR Engineering News Record
fps feet per second
GIS Geographical Information System
gpd gallons per day
I-5 Interstate 5
I& Infiltration and Inflow
IWRMP Integrated Water Resources Master Plan
Lathrop CTF Lathrop Consolidated Treatment Facility
LF Linear Feet
LS Lift Station
MGD Million Gallons per Day
MWQCF Manteca Wastewater Quality Control Facility
NPDES National Pollution Discharge Elimination System
OPC Opinion of Probable Cost
PS Pump Station
PVC Polyvinyl Chloride
PWWF Peak Wet Weather Flow
SCADA Supervisory Control and Data Acquisition
SLSP South Lathrop Specific Plan
SOI Sphere of Influence
TDH Total Dynamic Head
UWMP Urban Water Management Plan
VC Vitrified Clay
WDR Waste Discharge Requirements
WWSMP Wastewater System Master Plan
WWTF Wastewater Treatment Facility
eki environment
water
v
December 2024
EKI C20049. 02
324
2024 WWSMP Amendment
EXECUTIVE SUMMARY City of Lathrop

EXECUTIVE SUMMARY
EKI Environment & Water, Inc. ( EKI) has prepared this Wastewater System Master Plan Amendment WWSMP Amendment) for the City of Lathrop, California ( City). This WWSMP Amendment was developed as part of the 2024 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 WWSMP Amendment incorporates new information that has become available and changed planning assumptions since the completion of the 2019 IWRMP.

STUDY AND SERVICE AREAS
The City completed a General Plan Update in September 2022 ( Lathrop, 2022a) 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 revisions to the Central Lathrop area development plans.

The current population within the City is approximately 35, 080 as of January 2023 ( California DOF, 2023). The City has experienced significant growth and anticipates growth to continue in the future given the existing entitlements for several large residential developments.

CITY' S EXISTING WASTEWATER INFRASTRUCTURE
Wastewater from the City is treated at two facilities: ( 1) the Lathrop Consolidated Treatment Facility Lathrop CTF, or LCTF), and ( 2) the Manteca Wastewater Quality Control Facility ( MWQCF). The City' s allocated capacity at the MWQCF is 1. 451 million gallons per day ( MGD) of dry weather flow per the City' s 2002 Agreement Amendment with Manteca. The Lathrop CTF has a treatment capacity of

2. 5 MGD. The City is currently planning a Phase 3 Expansion that will expand CTF' s capacity to a total of

5. 0 MGD.

The City' s wastewater collection system consists of approximately 102 miles of gravity mains, 23. 6 miles of force mains, as well as 15 lift stations and pump stations. The City has a Supervisory Control and Data Acquisition ( SCADA) system for control and monitoring of facilities. The City' s wastewater infrastructure is shown on Figure ES -1.

EXISTING AND FUTURE WASTEWATER GENERATION
In 2022, the City generated a total average annual flow (AAF) of 2. 17 MGD, including 1.1 MGD treated at the MWQCF ( 51%) and 1. 06 MGD treated at the CTF ( 49%). The City' s average dry weather flow ADWF) was essentially equal to its AAF between 2017 and 2022, indicating minimal rainfall - induced infiltration and inflow ( I&). The total per capita ADWF is approximately 70 gallons of wastewater per capita per day.
eki environment
water
ES -1
December 2024
EKI C20049. 02
325
fL. eoendSphere of Influence
n Approximate Area of WWTF
Oa Pump Station or Lift Station
River Islands 2A PS
Valley Crossings LS
Stanford CrossingrPS
Mossdale PS'
BEIM
River Island
Mein PS

DE LIMA RD

DOS REIS RO
in North
Harlan PS
Stonebndge PS t.

Easy Ct LS
O St. PS
j1 Crossroads PS
I
Southoegrop PS
Lathrop CTF
Sherpe[ PS
Private)
Woodfield LS;

ILATHROP RD
California :
t Natural ProdLcts
PS ( Private)
McKinley I
Ave PS
Louise Ave PS
t LOWSE AV
SSI PS
ovate)
LIP LSet
fPn ate)
Lathrop
MWQCF Flow Getaway PS
YO3EMITE AV
Ga
Meter
MWQCF, r
Gravity Main Diameter, Inches
4-14-6
8 20-1
10 - 24
12 - > 30
Force Main Diameter, Inches
4 ••• 14-6
8 20-1
10 --- 24
12 - - > 30
Abbreviations
CTF = Consolidated Treatment Facility
LIP = Lathrop Industrial Park
LS = lift station
MWQCF = Manteca Water Quality Control Facility
pg = pump station
SSI = Super Store Industries
WWTF = wastewater treatment facility
Notes
1 All locations are approximate.

Sources
1 Aenel photograph provided by ESRI' s ArcGIS
Online, 14 May 2024.
3, 000 6, 000
SuN in Fmk)
City' s
Wastewater Infrastructure
Wastewater Svatem Master Plan Amendment
City of LethrOp
Lathrop, CA
ekiDecember, environment C20A8 00480A2
Water Figure ES -1
326

EXECUTIVE SUMMARY
2024 WWSMP Amendment
City of Lathrop
Land use -specific wastewater generation factors were updated using the 2017 through 2022 historic wastewater flow and parcel -level water use data. The wastewater generation factors serve as the basis to estimate ADWF for future developments. The IWRMP updated wastewater generation factors ( in units of gallons per day per dwelling unit or gallons per day per acre; gpd/ du or gpd/ ac) are presented in Table ES -1 below.

Table ES -1 Wastewater Flow Factors
Low Density Residential
Wastewater Flow
City -Wide
240 gpd/ du
Factor
River Islands
200 gpd/ du
Medium Density Residential 200 gpd/ du 155 gpd/ du
High Density Residential 110 gpd/ ac
Commercial 755 gpd/ ac
Industrial 240 gpd/ ac
Parks 55 gpd/ ac
Schools/ Institutional 220 gpd/ ac
Wastewater ADWF projections were calculated as the sum of the two major components of future wastewater flow: (1) the volume of wastewater that best represents existing wastewater generation within the City, and ( 2) the anticipated wastewater generation associated with the future development projects and planning areas.

The City' s projected wastewater generation by sector and by development area are estimated in fiveyear increments between 2025 and buildout in 2045. It is anticipated that the City' s total ADWF at buildout in 2045 is estimated to be 5. 67 MGD, which is 12. 5% lower than the projections included in the 2019 WWSMP of 6. 48 MGD. An ADWF of 1. 36 MGD is anticipated to flow to MWQCF from Historic Lathrop and 4. 31 MGD is projected to flow to the Lathrop CTF at buildout. The vast majority of the projected increase in wastewater generation at the CTF above current rates is associated with new development in River Islands and Central Lathrop.

WASTEWATER TREATMENT CAPACITY ASSESSMENT
The City' s allocation at the MWQCF is sufficient to meet the projected wastewater flows to MWQCF at buildout. Flows to the CTF is anticipated to exceed the current CTF capacity between 2030 and 2035.

The planned Phase 3 Expansion at the CTF will provide sufficient capacity to meet projected flows through buildout.

Both the MWQCF and the Lathrop CTF are observing increasing wastewater strength ( i.e. concentration of pollutants and nutrients in wastewater) likely due to improved water use efficiency during the recent droughts and in response to state regulations. The increases in influent wastewater strength may further limit treatment capacities at the treatment plants. To review the pollutant concentration in Lathrop' s
wastewater conveyed to the MWQCF, EKI conducted monitoring study during October 2022.

HYDRAULIC ASSESSMENT
EKI updated the sewer system hydraulic model to represent the City' s utility infrastructure as of January 2023. The hydraulic model was used to assess the ability of the City' s existing infrastructure to support the wastewater flow projections summarized in Section 4. Existing infrastructure was assessed under two scenarios: Existing ( 2022) and Buildout ( 2045).
eki environment
water
ES -3
December 2024
EKI C20049. 02
327
2024 WWSMP Amendment
EXECUTIVE SUMMARY City of Lathrop
The City' s collection system was primarily assessed against the capacity criteria, including depth to diameter ( d/ D) ratio in gravity mains and maximum velocity in force mains. Model results have shown that approximately 3% of City' s existing gravity mains will not meet the capacity criteria by 2045. Most capacity deficiencies identified in the Buildout scenario already exist in the existing system, although the degree of deficiency may increase with projected development.

Pump stations are evaluated against the ability to convey peak wet weather flow ( PWWF) within a station' sfirm capacity. A capacity deficiency has been identified in the Stonebridge Lift Station ( LS) in both the Existing and Buildout scenario. All other pump stations are projected to have sufficient capacities to meet existing and future PWWFs.

The City' s existing and planned force mains are able to convey projected wastewater flow through 2045.

RECOMMENDED CAPITAL IMPROVEMENT PROGRAM
The recommended collection system capital improvement projects ( CIPs) from the 2019 WWSMP and the City' s existing Capital Improvement Programs ( Lathrop, 2023) have been reviewed and confirmed to address the potential deficiencies identified in the updated hydraulic assessment. However, EKI recommends additional analyses be conducted to confirm the required project extents and infrastructure sizing. Modifications and additions were made to treatment projects based on findings from the wastewater treatment capacity assessment in Section 5.

Figure ES -2 shows an overview of the collection system capacity project locations, and Table ES -2 summarizes all the identified collection system improvement projects, including location, proposed improvements, estimated planning level costs, and alternatives.

Qki environment
G & water ES - 4
December 2024
EKI C20049. 02
328

EXECUTIVE SUMMARY
2024 WWSMP Amendment
City of Lathrop
Table ES -2. Recommended Capital Improvement Projects
Addresses
Project Modeled
Project Timeframe
Number Surcharging in
Existing Scenario
Treatment Facility Improvement Projects
Total Project OPC ( a)
WWT- 1 Manteca Interim Improvements Near -term (b)
WWT 2 CTF8; Phase 3 Expansion ( WW 22 -
Near
3CTF
term ( c) 23, 700, 000
WWT 3
Surface Water Discharge ( WW
20- 17) (d)
Existing 12, 699, 000
Total Treatment Facility Improvements OPC 36,99, 000
Collection System Improvement Projects
WW -1
Stonebridge Gravity Main
Replacement and Pump Station
Upgrade ( WW 22-5) (e)
Existing No 850, 00
WW 2A
Woodfield West Deficiency Project
Alternative A ( WW 22-6) Existing ( f) No 2, 730, 000
WW 26
Woodfield West Deficiency Project
Alternative B ( WW 22- 26) Existing ( f) No 2, 400, 000 WW -4
J Street Gravity Main Replacement
Project
Existing ( f) Yes 1, 690, 000
WW 5
Easy Court / O Street Gravity Main
Replacement Project
Existing No 1, 370, 000
WW -6 O Street Pump Station Upgrade Existing No 1, 560, 000 Total Collection System Improvements OPC 10, 600, 000
Miscellaneous Collection System Projects
WW -8 Temporary Flow Monitoring 100, 00
WW 9
Wastewater Lift Station Access
Modifications ( PW 24- 14) (d)
FY 23-5 CIP 475, 000
WW 9
Ozone Upgrade for Wastewater
Pump Stations ( PW- 24- 15) (d)
FY 23-5 CIP 75, 000
Total Miscellaneous Collection System Improvements OPC 650, 00 Notes:
a) Costs shown are presented in December 2024 dollars based on an ENR CCI of 13, 632. 41 (20 -city average).
b) City is currently evaluating the appropriate level of contribution to improvements at the MWQCF. c) City is currently issuing a request for proposal to PACE which may update this project OPC. d) Project included as a part of the City of Lathrop Capital Improvement Programs Fiscal Years 2023-025 report.
e) Connecting North Harlan Rd businesses which currently pump into the Stonebridge collection system to the North Harlan Rd SSFM can be considered as an alternative. f) Project addresses existing deficiencies, however future development influences recommended pipe or pump sizes to be installed.
eki environment
water
ES -5
December 2024
EKI C20049. 02
329
WW -2B: Woodfield West
Deficiency Project
Alternative B

DE LIMA RD

DOS REIS R
WW - 4: J Street
Gravity Main
Replacement
J
L WW- 1: Stonebridge Gravity Main
Replacement and Parlllel
Force Main
i
I/
WW -6: O Street
P, S Replacement
WW -5: Easy Court/ 0Street\
Gravity Main Replacement
Ia QQgp
CTF
WW -2A: Woodfield West
Deficiency Pioject - Alternative A
1 LATH ROP RD

MCKINLEY
AV

LLILOUISE AV
a
I
S1. ja' OSEMITE AV
egend
Sphere of Influence
i Approximate Area of WVVTF
D Pump Station or Lift Station
MO Pump Station or Lift Station Upgrade
Force Main
Gravity Main
Diameter of Replacement Sewer
e•
10"
12"
15"
18"
Diameter of New Force Main
Abbreviations
CTF = Consolidated Treatment Facility
MWQCF = Manteca Water Quality Control Facility
WWTF = wastewater treatment facility
Notes

1. All locations are approximate.

2. A detailed map for each project is Included in Appendix D.

Sources

1. Aerial photograph provided by ESRI• s ArcGIS Online, 12 March 2024.

N o
A _
2, 500 5, 000
Soak = Feel)
Recommended Collection System
Improvement Projects
Wastewater System Master Plan Amendment
City of Lahop
Lathro, CA
December ek,I
environment C2004802
water Figure ES -2
330
Section 1
Introduction
2024 WWSMP Amendment
City of Lathrop
1 INTRODUCTION
EKI Environment & Water, Inc. (EKI) has prepared this Wastewater System Master Plan Amendment WWSMP Amendment) for the City of Lathrop, California ( City). This WWSMP Amendment was developed as part of the 2024 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 WWSMP Amendment updates the City' s 2019 WWSMP ( 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 program ( 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 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 2019 IWRMP was completed, new information has become available and certain planning assumptions have changed that require an amendment to the IWRMP. The factors that influence this WWSMP Amendment include the following:

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 discharge a portion of the wastewater treated at the Lathrop Consolidated Treatment Facility ( CTF) in the San Joaquin River and deliver the remaining recycled water to retail customers. To support use of recycled water for landscape irrigation, the City obtained coverage under General Order WQ- 2019- 0058- DDW- R5017 and submitted a Title 22 Report Addendum in 2020. The City began delivering recycled water for urban uses in the summer of 2021 and discharging to the San Joaquin River in February 2024. 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.

Increases in Wastewater Strength: both the Manteca Wastewater Quality Control Facility MWQCF) and the Lathrop Consolidated Treatment Facility ( Lathrop CTF) are observing increasing wastewater strength ( i.e. concentration of pollutants and nutrients in wastewater) likely due to improved water use efficiency during the recent droughts and in response to state regulations. The recent increases in wastewater strength have resulted in decreased hydraulic capacities at the treatment plants and requires a reassessment of the City' streatment capacity against projected wastewater flows.

1. 2 Report Organization
The WWSMP is organized into the following sections:

Section 1 - Introduction
Section 2 - Study and Service Areas
Section 3 - City' s Existing Wastewater Infrastructure
eki environment
water
1-
December 2024
EKI C20049. 02
331
Section 1
Introduction
2024 WWSMP Amendment
City of Lathrop
Section 4 - Existing and Future Wastewater Generation
Section 5 - Wastewater Treatment Capacity Assessment
Section 6 - Hydraulic Assessment of the Collection System Section 7 - Capital Improvement Program Changes to the 2019 WWSMP Section 8 - References

1. 3 Scope of Work
The scope of work for the WWSMP Amendment included the following primary tasks:

Update of the wastewater system hydraulic model network to incorporate system improvements completed since the 2019 WWSMP or those currently in design or under construction;
Review of the City' s basic assumptions, criteria and conclusions in wastewater planning, e.g., wastewater system design criteria, pump station operations, and infiltration and inflow rates; Update of the land use -specific wastewater flow unit factors based on wastewater flow and water use between 2017 and 2021;
Development of wastewater generation projections based on land use consistent with the General Plan Update ( adopted September 2022) and River Islands Phase 2 project ( approved June 2021);
Verification and update of the peaking curve to evaluate peak wet -weather flows; Assessment of wastewater treatment capacity against updated wastewater flow projections; Assessment of the existing collection system under existing and future flow conditions using steady- state model simulations;
Evaluation of pump stations, force mains, and conveyance alternatives; Verification of the list of Capital Improvement Programs ( CIPs) included in the 2019 WWSMP; and
Preparation of the amended WWSMP document.
eki environment
water
1-2
December 2024
EKI C20049. 02
332
Section 2 2024 WWSMP Amendment
Study and Service Areas City of Lathrop
2 STUDY AND SERVICE AREAS
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' s Central 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 1-5. 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.

This section provides an overview of the City' s service area, including discussions of the City' sservice area boundaries, planned developments, and population.

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. The City' s Sphere of Influence ( SOI) is slightly larger with an area of about 13, 600 acres, or 21. square miles.

The City' sSOI includes two unincorporated areas:

1. Approximately 134 acres northeast of the City boundary and along Roth Road that is designated Freeway Commercial and Limited Industrial, and

2. Approximately 62 acres southeast of the City boundary that is designated Service Commercial and part of the Lathrop Gateway Business Park Specific Plan area.

The City reduced their SO1 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 1-5. 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' s wastewater collection system service area is generally contiguous with the City limits. The City currently provides wastewater service to approximately 6, 100 residential, commercial, industrial and institutional/ governmental properties.

A few large industrial facilities ( e.g., Simplot and California Natural Products) manage their wastewater onsite. California Natural Products independently treats and land applies most of their wastewater onsite and sends the remaining flows to the City' scollection system. The City began sewer service to the 724 - acre Sharpe Army Depot in 2022.

2. Specific Plans and Large Planned Unit Development
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. Infrastructure needs for these projects are evaluated in this document. These projects are described below and shown on Figure 2- 1 and Table 2-1, based on City and developer projections. Specifically, Table 2- 1 lists the number of new residential dwelling units and commercial, industrial, and institutional ( CII) acreage that is anticipated to be connected to the City' ssewer system in five- year increments between 2025 and the anticipated buildout at 2045. A general description of the development areas and the total development planned at buildout is described below.
eki environment
water
2- 3
December 2024
EKI C20049. 02
333
Section 2 2024 WWSMP Amendment
Study and Service Areas City of Lathrop
Central Lathrop Specific Plan. The Central Lathrop Specific Plan proposes development of 1, 520 acres located west of I-5. Phase 1 of the project is anticipated to be completed by 2040 and consists of a total of 579 high density units, 1, 483 variable density residential units, and 144 acres of commercial land uses. The project also includes two schools and 161 acres of recreational land use and open space. Phase 2 of the project includes 682 acres of light industrial use and a 5 -acre park.

Mossdale Landing. Mossdale Landing is a mixed - use master planned community that is anticipated to be completed by 2030. Construction at Mossdale Landing began in 2003 and approximately 1, 640 residential units have been constructed thus far. An additional 66 low density are anticipated by project completion. In addition, the development is allocating a total of 35 acres of land for two schools, 40 acres for parks, and 25 acres for commercial development.

Mossdale Landing East. Mossdale Landing East ( formerly referred to as Lathrop Station) is anticipated to be completed by 2030. Approximately 490 residential units have been constructed so far. An additional 37 low density units are anticipated by project completion. The development plan also includes a total of 6. 5 acres of village commercial, 13. 2 acres of service commercial, and 27. 5acres of highway commercial land uses.

Mossdale Landing South. Mossdale Landing South is a proposed 104 -acre development that is anticipated to be completed by 2030. Approximately 140 medium and high density units have been constructed so far. An additional 85 medium density units are anticipated by project completion. In addition, the project includes a total of 28 acres of commercial, 25 acres of open space, and 9. 5 acres of parks.

Mossdale Landing West. Mossdale Landing West is a proposed residential development that is anticipated to be completed by 2032. The project will be located on the Silveira property and consist of 829 low density dwelling units and 11 acres of parks.

River Islands. The 4, 995 -acre River Islands development is located west of the San Joaquin River and east of Paradise Cut on land known as the Stewart Tract. The development proposes a mixture of low, medium and high density residential units. According to its recently amended Specific Plan, River Islands will consist of two phases and a total of 15, 000 homes, a 260 -acre employment center, a 79 -acre town center, 235 acres of parks and ten schools. About 2, 800 low density residential units were constructed and occupied by late 2022. The estimated project completion date is 2040 ( Lathrop, 2022b; Woodard & Curran, 2020).

Lathrop Gateway Business Park Specific Plan. The Lathrop Gateway Business Park Specific Plan proposes commercial and industrial development of approximately 384 acres to be completed by 2040. The City annexed 213 acres of this area in June 2012 and 99 acres of the remaining 117 acres in May 2016. This would result in approximately 4. 7 million square feet of service commercial, limited industrial, distribution, and research and development related uses, and approximately 741, 000 square feet of commercial office and retail uses. The first phase of the project includes approximately 167 acres of limited industrial, 83 acres of service commercial, and 57 acres of office and commercial retail uses and is anticipated to be completed by 2030.

South Lathrop Specific Plan. The South Lathrop Specific Plan was approved by the City Council on 20 July 2015 and includes a 315 - acre plan area. The Specific Plan proposes approximately 10 acres of commercial office uses, 246 acres of limited industrial, 31 acres of open space, and 27 acres of roads and public facilities. The City South Lathrop Specific Plan area was annexed into the City in May 2016. The South Lathrop Commerce Center, approximately 272 acres within eki environment
water
2-4
December 2024
EKI C20049. 02
334
Section 2 2024 WWSMP Amendment
Study and Service Areas City of Lathrop
the South Lathrop Specific Plan, is anticipated to be completed by 2030. The South Lathrop Commerce Center will encompass all of the South Lathrop Specific Plan area with the exception of approximately 24 acres of light industrial, 1. 2 acres of office commercial, and 19 acres of open space and public roads.

Historic Lathrop Infill and Other Developments East of I-5. The portion of the City east of I-5 is anticipated to expand and add density in the future. Currently, this area consists of approximately 3, 160 low density and 455 medium density units, commercial and industrial areas, and a few public parks. Future residential growth of this area is expected on undeveloped/ underutilized and redeveloped parcels consolidated from large lots where low density residential units would be demolished. New residential projects are estimated to consist of 52 low density, 218 medium density, and 48 high density residential units, increasing the total existing residential unit count by 318 units.

Sharpe Army Depot. During World War II, the US Army created the Sharpe Army Depot ( Depot) in the rural Lathrop Community to allow shipment of major army supplies to the western United States. The Depot is comprised of a 724 -acre facility south of Roth Road and has served both the Army and Airforce with a variety of supplies depending on the demand of goods and supplies created by war time efforts. The Depot is occupied by the AAFES West Coast Distribution Center that employs 348 workers. Prior to 30 September 2014 the Defense Logistics Agency was also housed at the Depot; its workforce of 700 workers has since been transferred to the larger Tracy Army Depot. The City began providing water and sewer services to the Sharpe Army Depot in 2022, including the AAFES and the California National Guard properties. eki environment
water 2- 5
December 2024
EKI C20049. 02
335
River
Islands
ti5\
Area of ! Mao*
Central
enkn
Alley
Doom
IPstorro Lathrop ! Moll
and Oliser Developments
ari c.w
cwara.. nm
lDrLe_ endCity Limit
173 Sphere of Influence
EDArea of Interest
EDRail Cargo Container Yard
Development Areas
Central Lathrop
QCrossroads
Historic Lathrop lab and Other Developments
ED Lathrop Gateway
EZI Mossdale Landing
r- Mossdale Landing West
Mossdale Landing East
Mossdale Landing South
River Islands
Sharpe Army Depot
Q South Lathrop
Notes

1. All locations are approximate.

Sources

1. Aerial photograph provided by ESRI' s ArcGIS Online, 12 March 2024.

N
o
A
4, 000 8,000
Sole in FM)
eki
City of Lathrop Boundaries
and Development Areas
Wastewater System Master Plan Amendment
City of Latnron
Lathrop, CA
mber
environment DaceC2004a02 czoo4e Dz
water Figure 2- 1
336
Section 2
Study and Service Areas
2024 WWSMP Amendment
City of Lathrop
Table 2-1
City of Lathrop Wastewater Development Projections by Development Area Land Use Designation
Central Lathrop Phase 1
Units
2025 2030 2035 2040
Incremental New Development ( a)( b) Total New
2045 Development
Buildout)
Low Density Residential du 500 264 764
High Density Residential du 246 210 123 579
Commercial ac 13. 0 60. 72. 0 145. 6
Mixed Use ac 51. 0 51. 0
Parks ac 39 5. 0 44. 1
CentralLathrop - Phase 2
Light Industrial / R&D Flex ac 90 592 682
Parks ac 5 5
Mossdale - All Developments ( c)
Low Density Residential du 37 829 66 932
Medium Density Residential du 85 85
High Density Residential du 84 84
Commercial ac 4. 6 8. 5 8. 0 17. 0 38. 1
Parks ac 4. 0 11. 0 15. 0
Schools ac 16. 2 16. 2
Mossdale Landing
Low Density Residential du 66 66
Medium Density Residential du 0
High Density Residential du 0
Commercial ac 4. 6 1. 5 6
Schools ac 16. 2 16
Mossdale Landing East
Low Density Residential du 37 37
High Density Residential du 84 84
Commercial ac 7. 0 7
Mossdale Landing South
Medium Density Residential du 85 85
Commercial ac 8. 0 17. 0 25
Parks ac 4. 0 4
Mossdale Landing West
Low Density Residential du 829 829
Parks ac 11. 0 11
River Islands
Low Density Residential du 768 1, 218 1, 218 1, 218 4,22 Medium Density Residential du 676 945 945 945 3, 511
High Density Residential du 1, 395 1, 395 1, 395 4, 185 Town Center ac 26. 3 26. 3 26. 3 79
eki environment
water
December 2- 024
EKI C20049. 02
337
Section 2
Study and Service Areas
2024 WWSMP Amendment
City of Lathrop
Table 2-1
City of Lathrop Wastewater Development Projections by Development Area Land Use Designation Units
ac
Incremental
2025 2030

86. 1
New Development
2035

86. 1
2040

86. 1
a)( b)
2045
Buildout)
Total New
Development
Commercial 258
Schools ( d) ac 32. 5 15. 0 15. 0 14. 0 77
Parks ac 19. 0 60. 9 61. 0 61. 0 201. 9
South Lathrop
Light Industrial / R&D Flex ac 67. 0 32. 8 99. 8
Office Commercial ac 8. 1. 2 10. 0
Lathrop Gateway
Light Industrial / R&D Flex ac 66. 0 16. 6 82. 6
Office Commercial ac 51. 0 11. 7 62. 7
Open Space ac 2. 5 1. 6 4. 1
Crossroads ( c)
Industrial ac 23. 0 23. 0
Commercial ac 1. 5 1. 5
Historic Lathrop and Other Development Areas ( c)
Low Density Residential du 12 6 5 29 52
Medium Density Residential du 27 26 26 26 113 218
High Density Residential du 48 48
Commercial ac 22. 0 13. 6 8. 0 43. 6
Industrial ac 18. 0 24. 0 42. 0
Sharpe Army Depot
Industrial ac d) d)
Notes:
a) Dwelling unit counts and acreages were based on information provided by developers and the City in July 2020 and April 2023.
b) Includes dwelling units and acreages that are assumed to be developed during the preceding five- year period. Dwelling units and acreages shown for 2025 are those assumed to be developed between January 2023 and December 2025. Dwelling units and acreages developed before December 2022 are included in baseline wastewater flow (see Table 4-6).
c) Future development located in the Historic Lathrop Development Area that are anticipated to be discharging to the CTF are listed under the Crossroads Development Area for the purposes of this document.
d) The AAFES facility and the CMD facility at the Sharpe Army Depot are connected to City' ssewer system as of January 2023.
eki environment
water
December 2024
EKI C20049. 02
338
Section 2 2024 WWSMP Amendment
Study and Service Areas City of Lathrop

2. 3 Current and Projected Population
Values for the historical and current population within the City' s water service area were obtained from
data reported by the California Department of Finance ( DOF) within the City Limits. Although Lathrop' s water service area includes a railroad cargo container commercial enterprise that is outside the City limits, the service area population is estimated to be equivalent to the City population. As of January 2023, the population estimate for Lathrop was 35, 080 (California DOF, 2023). The historical and current population data within the City' swater service area are presented in Table 2-.

Population in the City has grown by approximately 410% over the 32 -year period between 1990 through 2023, from approximately 6, 800 to 35, 100 (California DOF, 2007, 2012, and 2023). Between 2005 and 2023, the population increased by 174%, from approximately 12, 800 to 35, 100.

The City anticipates that population will continue to grow in the future given the existing entitlements for several large residential developments, discussed above in Section 2.. The population projections for 2025 through 2045, summarized in Table 2-3, are estimated using the existing population ( as determined by California DOF) and adding the amount of new housing anticipated to be permitted in each five- year increment based on Table 2-1. The population added each year is projected by multiplying the most recent number of new housing units by ( 1) 4. 02 person per dwelling unit based on Census data for low density developments, which consists of a large majority of the City' s existing land uses and ( 2) 3. 0 persons per dwelling units for future medium density and high -density dwelling units U. S. Census, 2023). Current and projected population trends are shown on Figure 2-. eki environment
water
2-9
December 2024
EKI C20049. 02
339
Section 2
Study and Service Areas
2024 WWSMP Amendment
City of Lathrop
Table 2-. Historical City of Lathrop Population
Year
1990
Service Area Population ( a)
6, 841
Annual Growth Rate
1991 7, 018 2.6%
1992 7, 063 0.6%
1993 7, 434 5.3%
1994 8, 410 13.%
1995 8, 713 3.6%
1996 9, 031 3.6%
1997 9, 172 1.6%
1998 9, 508 3.7%
1999 9, 786 2.9%
2000 10, 445 6.7%
2001 10, 802 3.4%
2002 11, 616 7.5%
2003 12, 089 4.1%
2004 12, 482 3.%
2005 12, 768 2.3%
2006 14, 489 13. 5%
2007 16, 271 12. 3%
2008 17, 282 6.2%
2009 17, 589 1.8%
2010 18, 023 2.5%
2011 18, 688 3.7%
2012 19, 090 2.%
2013 19, 642 2.9%
2014 20, 158 2.6%
2015 20, 796 3.2%
2016 22, 174 6.%
2017 23, 117 4.3%
2018 24, 185 4.6%
2019 25, 401 5.0%
2020 26, 833 5.6%
2021 29, 384 9.5%
2022 31, 575 7.5%
2023 35, 080 11.%
Notes:
a) Historical and current population is based on population estimates by the California DOF for the City of Lathrop included in DOF, 2007; DOF, 2012; DOF, 2022; and DOF, 2023. eki environment
water
2- 10
December 2024
EKI C20049. 02
340
Section 2
Study and Service Areas
2024 WWSMP Amendment
City of Lathrop
Population
Served
Table 2-3. Current and Projected City of Lathrop Population Current and Projected Service Area Population ( a)( b)
Year 2023 2025 2030 2035 2040
2045
Buildout)
Population Served 35, 080 40, 531 55, 471 72, 513 84,97 86, 013 Notes:
a) Current population is based on population estimates by the California DOF for the City of Lathrop included in DOF, 2023.
b) Projected populations for 2025 through buildout ( 2045) are based on residential unit counts from Table 2-1, multiplied by 4. 02 persons per dwelling unit for low density developments ( U. S. Census, 2023) and 3. 0 persons per dwelling unit for medium and high density developments.
100, 00
90, 000
80, 000
70, 000
60, 000
50, 000
40, 000
30, 000
20, 000
10, 000
eki
0 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 Year
Figure 2-. Historical and Projected City of Lathrop Population Historical Population — 8 — Projected Population
environment
water
2- 11
December 2024
EKI C20049. 02
341
Section 3
2024 WWSMP Amendment
City' sExisting Wastewater Infrastructure City of Lathrop 3 CITY' SEXISTING WASTEWATER INFRASTRUCTURE
Wastewater from the City is treated at two facilities: the regional MWQCF and the City -owned Lathrop CTF. The City' s wastewater collection system, including the City' s lift station and pump station drainage areas, 1is shown on Figure 3-1. The City' s wastewater utilities are discussed in more detail in the sections below.

3. 1 Wastewater Collection
The City' s wastewater collection system consists of approximately 102 miles of gravity mains, 23. 6 miles of force mains, as well as 16 lift and pump stations. The City has a supervisory control and data acquisition ( SCADA) system for control and monitoring of facilities.

As shown on Figure 2-, most of the City' s wastewater generated in the areas east of I-5 is conveyed to the MWQCF; wastewater generated in the Crossroads, South Lathrop, and Lathrop Gateway industrial areas and the areas west of I-5, including the Mossdale, River Island, and Central Lathrop areas, is conveyed to the Lathrop CTF.

A few large industrial facilities ( e. g., Simplot and California Natural Products) manage their wastewater onsite. California Natural Products manages the majority of their wastewater and sends the remaining flows to either the J Street Lift Station ( LS) or the McKinley Avenue Pump Station ( PS).

3. 1. Gravity System
Table 3-1 summarizes the City' s gravity main inventory by diameter. Gravity main sizes are also shown on Figure 3-1.

Approximately 66% of gravity mains are polyvinyl chloride ( PVC) pipes, and the remaining 34% are vitrified clay ( VC) pipes. All the VC pipes are located in the older Historic Lathrop and Crossroads areas.

Newer areas of the City west of I-5 are exclusively served by PVC pipe, which is the City' s current standard pipe material.
1 Generally, lift stations add hydraulic head to the wastewater flow within the gravity collection system; pump stations pressurize wastewater flow for conveyance via force mains. eki environment
water
3- 1
December 2024
EKI C20049. 02
342
River Islands 2A PS
L Sphere of Influence
nApproximate Area of W WfF
CD Pump Station or Lift Station
Stanford Cross_ ing. PS
Mossdale P31
Valley Crossings LS

DE LIMA RD

DOS REIS RD
I
North
Harlan PS
tonebridge PS
i
Sharpe[ PS
Private))
Woodfield LS:

II. ATHROP RD
California
t Natural Products
ps I
PS ( Private)
McKinley
Ave PS
Louise Ave PS
Easy Ct LS
O St PS
Z
Lathrop CTF
t -

OUISE AV
SSI PS
i` vale)
2 LIP LS!
Private)
1 Lathrop ''— .

OSEMITEAV
Ga away PS MWQCF, FIow
j
I
Crossroads PS 0. Met r
River Islands , •• tc
i
Mein PS ‘/
oth• Lhrop PS
y ..

Gravity Main Diameter, Inches
4-14-6
6 - 18
8 20-1
10 - 24
12 - > 30
Force Main Diameter, Inches
8 20-1
12 - - > 30
Abbreviations
CTF = Consolidated Treatment Facility
LIP = Lathrop Industrial Perk
LS = lift station
MWQCF = Manteca Water Quality Control Facility
PS = pump station
SSI = Super Store Industries
WWTF = wastewater treatment facility
Notes

1. All locations are approximate.

Sources

1. Aerial photograph provided by ESRI' s ArcGIS
Online, 14 May 2024.

N
o 3, 000 o, 000
A ( scale in Feet)
Citys Wastewater Infrastructure
Wastewater System Master Plan Amendment
Ciry of Lathrop
Lathrop, CA
ski environment DecemberC2004902
water
C20043
Figure 3- t1
343
River Islands 2A PS
Stanford Crossin
f
Mossoale F'
River Islands
Main PS
North
Harlan.. PS
Valley Crossings LS Stonebndg

DE LIMA RD
South
Lathrop CTF
La hrop
Gateway PS
Lathrop PS
pe PS
vale)

LATHROP RD
ducts
owse Ave PS
t CHASE AV
SSI PS
Rnvate)
te)

SEMRE AV
MWQCFFlow
Meter

MWOCCFF
Legend
rJ Sphere of Influence
r Approximate Area of W WTF
NI Pump Station or Lift Station
Force Main
Gravity Main
WWTP Drainage Area Boundaries
Lathrop CTF Collection System
MWQCF Collection System
Pump Station Drainage Areas
MIN Stanford Crossing - Mossdale
Crossroads ` O St
ME Easy Ct River Islands
t"L,` J St South Lathrop
Lathrop Gateway Stonebridge
MI Manteca FiSN, Valley Crossing
NE McKinley Woodfield
Abbreviations
CTF = Consolidated Treatment Facility
LIP = Lathrop Industrial Perk
LS = lift station
MWQCF = Manteca Water Quality Control Facility
PS = pump station
SSI = Super Store Industries
W WTF = wastewater treatment facility
Notes

1. All locations are approximate.

Sources

1. Aerial photograph provided by ESRI' s ArcGIS
Online, 12 March 2024.

N
o 3, 000 6O00
A ( Scale in Eeen
City' s Wastewater Pump Station Drainage Areas
Wastewater System Master Plan Amendment
Cry of Lathrop
Lathrop, CA
ski environment December 2024
water
020049. 02
Figure 3-2
344
Section 3 2024 WWSMP Amendment
City' sExisting Wastewater Infrastructure City of Lathrop Table 3-1. Collection System Inventory
Pipe Diameter Total Pipe Length
Percent of System
inches) ( miles)
Gravity Mains
6 8. 6 8%
8 71. 9 70%
10 6. 7 6.%
12 5. 8 5.7%
14 0. 5 0.5%
15 2. 9 2.8%
16 0. 1 0.1%
18 1. 3 1.3%
20 0. 4 0.4%
21 0.2 0.2%
24 1. 5 1.5%
30 1. 9 1.9%
36 0. 6 0.6%
42 0. 1 0.1%
Total 102. 2 100%
Force Mains
4 1. 2 5%
6 4. 3 18%
8 2. 5 11%
10 0. 7 3%
12 7. 3 31%
14 3. 1 13%
16 1. 8 8%
18 2. 7 11%
Total 23. 6 100%
Notes:
a) Does not include laterals.
eki environment
water 3- 4
December 2024
EKI C20049. 02
345
Section 3 2024 WWSMP Amendment
City' sExisting Wastewater Infrastructure City of Lathrop

3. 1. 2 Pump Stations and Force Mains
Table 3- 2 summarizes the characteristics of each of the City' s lift and pump stations and their associated force mains. The direct tributary areas of each lift station or pump station, or " drainage areas", are shown on Figure 3-2. A schematic of the City' s lift stations and pump stations that shows how wastewater flows through the collection system is illustrated on Figure 3-. An inventory of the City' s force main sizes is summarized in Table 3-1.

The City' s wastewater generated east of I-5 and north of Louise Avenue in the Historic Lathrop area is conveyed via gravity sewers and lift stations to either the O Street PS or the McKinley Avenue PS.

Wastewater from the McKinley Avenue PS and O Street PS converge at the McKinley intertie, which is capable of sending converged flow via a 12 -inch and/ or a 16 -inch diameter force main to the MWQCF.

These force mains also convey wastewater from the Louise Avenue pump station and other private pump stations that serve the industrial areas east of I-5 to the MWQCF.

Wastewater from the CLSP, Mossdale, River Islands, South Lathrop, and Lathrop Gateway areas are conveyed via gravity sewers to a main pump station within each development area. These pump stations then send wastewater directly to the Lathrop CTF.

3. 1. Collection System Intertie
The City' stwo collection systems are connected by the 8 -inch Mossdale Intertie, which crosses beneath I-5 on River Islands Parkway and Louise Avenue. The intertie may convey flow from the Mossdale PS to sewer mains upstream of the East Street LS but is limited by the capacity of sewers in the Easy Street area. The intertie is not routinely operated but could potentially be utilized in the future to reroute a portion of flows from the Mossdale PS to the MWQCF tributary area.

3. 1. 4 Major Collection System Improvements Completed Since 2019 The following major wastewater collection system improvements were completed since the 2019 WSMP:

CLSP sewer infrastructure and Stanford Crossing Pump Station: infrastructure improvements in the Central Lathrop Phase 1 ( Stanford Crossing) area were constructed including gravity mains, pump station, and connection to existing 14 - inch and 18 - inch force mains which convey wastewater flow from buildout of Central Lathrop Specific Plan ( CLSP) area to the CTF.

River Islands: sewer infrastructure was expanded for Phase 2A/B of the River Islands development, including a gravity collection system, the River Islands 2A PS, and the River Islands Main PS which connects to existing 12 -inch and 18 -inch diameter force mains conveying flows to the Lathrop CTF.

South Lathrop: a new gravity collection system along Yosemite Ave was constructed to collect wastewater from commercial facilities in its vicinity to a new pump station, which then conveys flows to the CTF via dual 6 -inch force mains.

Lathrop Gateway: a new 10 -inch diameter gravity collection system along Business Park Court. was constructed to collect wastewater from commercial facilities in its vicinity to a new pump station, which then conveys flows to the CTF via a new 4 -inch and 6 -inch diameter force mains.

Woodfield Pump Station: the Woodfield PS was upgraded and connected to the 10 -inch diameter force main that flows to the gravity mains upstream of the McKinley Avenue PS.

North Harlan PS: the private pump station has been upgraded to a public pump station.

These completed projects are incorporated in the WWSMP evaluation of the existing wastewater collection system.
eki environment
water
3- 5
December 2024
EKI C20049. 02
346
Section 3
City' sExisting Wastewater Infrastructure
2024 WWSMP Amendment
City of Lathrop
Table 3-2. Summary of Wastewater Pump Station Characteristics Number
Force Main Existing Existing Firm
Pump Station
of Pumps
Rated Power Diameter Design Capacity Capacity
in) ( gpm) ( gpm)( a)
MWQCF Collection System
North Harlan PS 2 10 HP 6" 2, 150 1, 075
Stonebridge LS 2 10 HP 6" 700 350
Woodfield LS 3 5 HP 8" (b) 1, 230 820
Valley Crossing LS ( b) 2 3 HP 4" 83 83
J Street LS 2 10 HP 8" 1, 400 700
Easy Court LS 2 3 HP 1, 000 500
O Street PS 3
Two at 70 HP;
one at 5 HP
12" 4, 200 2, 800
McKinley Avenue PS 3
Two at 25 HP;
one at 5 HP
16" 2, 513 1, 675
Louise Avenue PS 2 5 HP 4" d) d)
Lathrop CTF Collection System
Stanford Crossing 2
One at 90 HP;
One at 45 HP
14" & 18" 4, 100 2, 300
Mossdale PS 4 30 HP 8" & 12" 5, 400 4, 050
River Islands Main PS 2 ( c) 110 HP 12" & 18" 3, 400 1, 700 River Islands 2A PS 4 15 HP 30" 5, 300 3, 975
Lathrop Gateway PS 2 23 HP 4" & 6" 560 280
South Lathrop PS 3 12 HP 6" & 6" 2, 775 1, 850
Notes:
a) Firm pumping capacity defined as the total capacity of all pumps minus the capacity of the largest pump. b) Capacity of the 8" outlet is listed as the lift station capacity, as it is the capacity limiting component of this pump station.
c) River Islands Sewer PS will be constructed in phases with addition of two pumps during each phase. eki environment
water
3-6
December 2024
EKI C20049. 02
347
Section 3
City' sExisting Wastewater Infrastructure
2024 WWSMP Amendment
City of Lathrop
Stanford
Crossing PS
River Islands
Main PS
River Islands
2A
Figure 3-. City' s Wastewater Collection System Schematic Mossdale PS
Lathrop
CIF
South
Lathrop PS
Mossdale
Intertie
Valley
Crossing LS
Easy Court
LS
Crossroads
PS
Lathrop
Gateway PS
North
Harlan PS
Stonebridge
LS
Woodfield
PS
CNP PS
private)
J Street PS
O Street PS
4 Louise Ave
PS
McKinley
Intertie
Valve Box
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. b) Heinz - Kraft, Sharpe, and LIP private pump stations not shown. eki environment
water
3- 7
December 2024
EKI C20049. 02
348
Section 3 2024 WWSMP Amendment
City' sExisting Wastewater Infrastructure City of Lathrop

3. 2 Wastewater Treatment
Wastewater treatment at the MWQCF and the Lathrop CTF are discussed in the following sections.

3.2. 1 Manteca Water Quality Control Facility
The City owns approximately 14. 7% of the existing MWQCF capacity by contract with the City of Manteca. However, the City does not participate in the operation of the plant, nor does it receive recycled water from MWQCF. Per the City' s 2002 Agreement Amendment with Manteca and as listed in Table 3-, the total current MWQCF design capacity is 9. 87 million gallons per day ( MGD) and the City' s allocated capacity is 1. 451 MGD ( Lathrop County Water District and the City of Manteca, 2002). Under the Agreement Amendment, the City has the right to 1. 451 MGD dry weather flow, 2. 321 MGD peak wet weather flow, 3, 751 pounds per day of biochemical oxygen demand ( BOD), and 3, 812 pounds per day of total suspended solids ( TSS). However, as discussed in Section 5. 2, recent increases in wastewater strength may limit MWQCF' streatment capacity and, as a result, the City' sshare of MWQCF capacity.

The MWQCF is permitted for future expansions of up to 26. 97 MGD, of which the City would be allocated up to 3. 97 MGD, should the City elect to fund its share of the expansions to maintain its proportional allotment.

Treatment at the MWQCF consists of primary sedimentation followed by roughing biotowers, conventional activated sludge, secondary clarification, tertiary filtration, and ultraviolet disinfection.

Disinfected tertiary effluent is discharged to the San Joaquin River. A portion of the secondary effluent is not disinfected and is used to irrigate crops on 190 acres of land owned by the City of Manteca ( WDR Order No. R5- 2015- 0026).

Table 3-. Wastewater Capacity Allocation at MWQCF
Phase
Existing
Build - Out ( 2050)
Allocated Capacity at MWQCF ( MGD)
City of Manteca City of Lathrop

8. 42

23. 00

1. 45

3. 97
Total

9. 87

26. 97

3. 2. Lathrop Consolidated Treatment Facility
The City owns a membrane bio reactor (MBR) treatment facility, the Lathrop CTF, that also incorporates portions of the old Crossroads Industrial Wastewater Treatment Plant. Daily operations of the Lathrop CTF are contracted to Veolia Water, North America. The City completed the Phase 2 Expansion of the Lathrop CTF in 2019 which increased the plant' streatment capacity to 2. 5 MGD. The City has the ability to further upgrade Lathrop CTF to increase the treatment capacity up to 9. 0 MGD as needed. 2 As discussed in Section 5.2, recent increases in wastewater strength may limit the CTF' streatment capacity.

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). Wastewater treatment processes at the Lathrop CTF include secondary 2 The City had previously completed a project -level Environmental Impact Report ( EIR) for treatment capacity up to

6. 0 MGD at the CTF. Post combination with Crossroads WWTF, the program - level EIR treatment capacity at the CTF has increased to 9. 0 MGD.
eki environment
water
3- 8
December 2024
EKI C20049. 02
349
Section 3 2024 WWSMP Amendment
City' s Existing Wastewater Infrastructure City of Lathrop treatment, tertiary membrane filtration, and disinfection prior to storage and disposal. The current Lathrop CTF is capable of treating Peak Day Flows of 4. 0 MGD at a loading of 14, 000 pounds of BOD per day and Peak Hour Flows of 7. 5 MGD.

With the rapid increase of wastewater generation anticipated within the City and the CTF drainage area, the City is planning Phase 3 expansion of the Lathrop CTF in the near future. The Phase 3 expansion is anticipated to add 2. 5 MGD of capacity to a total of 5. 0 MGD capacity.

The Lathrop CTF produces disinfected tertiary recycled water suitable for irrigation at parks, landscape strips, median islands, pond berms, and agricultural fields. The City is covered under General Order WQ2016- 0068- DDW (General Order) for recycled water use in a total of 196 acres of landscape irrigation areas in the River Islands, Mossdale, and Central Lathrop areas.

In 2021, the City obtained a National Pollutant Discharge Elimination System ( NPDES) permit for surface water discharge ( Order R5- 2022- 0004). 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 completed the following infrastructure improvements to implement its NPDES permit and began discharging to the San Joaquin River in February 2024:

CTF
o Retrofitting of the existing chlorine contact exit structure to a new dechlorination station with overflow pipes to send chlorinated effluent ( Title 22 recycled water) to S5 and dechlorinated effluent to the Crossroads Pump Station. o New piping from the dechlorination station to the existing Crossroads Pump Station. o Abandoning of the piping from Ponds A, B and C to the Crossroads Pump Station o New piping that connects the existing discharge line from the Crossroads Pump Station to the CTF headworks, which will divert substandard effluent from the outfall, and disconnection of the existing discharge line from PB- 1. o New piping to connect PMP- 1to percolation pond PB- 1.

Effluent Discharge Pipeline
o Approximately 2, 000 linear feet ( LF) of a new dedicated discharge line and railway crossing from the Crossroads Pump station along Tesla Way to connect to an existing 18" pipeline at Murphy Parkway and Tesla Way.
o Reuse of approximately 3,00 LF of existing 18 - inch pipeline along Tesla Way and Harlan Road from Murphy Parkway to Sadler Oak.
o Reuse of approximately 1, 800 LF of existing 20 -inch pipeline along Sadler Oak from Harlan Road to the RD - 17 levee.
o Reconstruction of the 20 -inch pipeline where it crosses the levee and extension of the pipeline to a new outfall approximately 350 feet further downstream ( north).

Outfall Structure
o A new side bank outfall located approximately 350 feet downstream from the Crossroads storm drain pump station outfall.
eki environment
water
3-9
December 2024
EKI C20049. 02
350
Section 3 2024 WWSMP Amendment
City' sExisting Wastewater Infrastructure City of Lathrop The City began discharging CTF effluent to the San Joaquin River in February 2024 and plans to retire its agricultural land application areas and decommission the majority of its recycled water storage ponds and percolation pond PB- 1 (EKI, 2024).
eki environment
water
3- 10
December 2024
EKI C20049. 02
351
Section 4 2024 WWSMP Amendment
Existing and Future Wastewater Generation City of Lathrop 4 EXISTING AND FUTURE WASTEWATER GENERATION
As part of the IWRMP, the City evaluated its existing wastewater flows and updated its flow projections.

The following sections summarize the City' s historical and current wastewater generation, wastewater flow projections, and wastewater peaking factors.

Wastewater flows in a sanitary sewer system typically consist of the following components:

Base sanitary flow ( BSF): BSF is the sanitary wastewater flow from domestic, commercial, industrial, and institutional uses.

Infiltration: Infiltration refers to groundwater that enters a sewer system through defective pipes, pipe joints, connections, or manholes.

Inflow: Inflow refers to stormwater that enters a sewer system through direct connections, such as manhole covers and defective sewer service cleanouts or ( illegal) roof drains, foundation drains, catch basins, or area drain connections.

Infiltration and Inflow are collectively referred to as " I&". The amount of I&tends to be smaller in new collection systems but is generally observed to increase over time due to wear and tear on the collection system.

The following terminology is used throughout this document to describe variations in wastewater flow:

Average annual flow ( AAF): AAF refers to the average daily flow over the entire year and is inclusive of BSF and I&.

Average dry -weather flow ( ADWF): ADWF refers to the average daily flow for the months of June, July, and August ( i.e., during the dry season). ADWF includes BSF and infiltration, but not inflow.

Peak wet weather flow ( PWWF): PWWF refers to the peak hourly flow, which includes peak diurnal BSF, infiltration, and inflow from storm events.

EKI reviewed the following available information for evaluation of wastewater flows as part of this WWSMP update:

Daily flow data collected between January 2017 and December 2022 from the headworks of the Lathrop CTF;
Daily flow data collected between January 2017 and December 2022 from the flow meter on Yosemite Avenue that measures the City' sflow to the MWQCF; Available discharge flow and level data recorded in 5 -minute intervals from the City' s lift stations and pump stations by the SCADA system between January 2017 and December 2021; and
Daily discharge flow for the City' s lift stations and pump stations recorded by the City' s operators between January 2017 and December 2021.

4. 1 Current and Historical Wastewater Flow
Table 4-1 and Table 4-2 provide historical context by summarizing the City' s wastewater generation, service area population, and per -capita wastewater generation for the years 2009 through 2022.

Table 4- 1 lists the total AAF, citywide and by treatment facility, and per -capita AAF. Table 4-2 lists the same information on an ADWF- basis, and compares AAF to ADWF along with Figure 4- 1 and Figure 4-2. eki environment
water
4-1
December 2024
EKI C20049. 02
352
Section 4
Existing and Future Wastewater Generation City of Lathrop 2024 WWSMP Amendment
The City' s total AAF and ADWF showed a steady increasing trend between 2009 and 2022. Although there was a period of slower growth between 2014 and 2016, the City' s wastewater flow appears to be insensitive to the recent droughts. During the period between 2017 and 2022, the City' s AAF increased at an annual rate of approximately 7%, comparable to the City' s population growth. In 2022, the City generated a total AAF of 2. 171 MGD, including 1.06 MGD treated at the MWQCF ( 51%) and 1. 065 MGD treated at the CTF ( 49%).

The comparison between AAF and ADWF is calculated in Table 4-2, which is an indication of the amount of rainfall -induced l&I collected during a given year. The ADWF to AAF ratio between 2017 and 2022 averaged 103%, indicating that the ADWF is essentially equal or at times, higher than the AAF.

The total per capita AAF and ADWF also showed an increasing trend between 2009 and 2022, despite temporary declines during the economic recession between 2009 and 2012 and the historic drought between 2014 and 2015. The per capita ADWF varied between 67 and 75 gallons of wastewater per day per capita between 2017 and 2022.

Table 4-1. Current and Historical Wastewater AAF and Per Capita AAF Year
2009
Average
MWQCF
MGD)

0. 706
Annual Flow ( AAF)
CTF ( b)
MGD)

0. 287
a)
Total
MGD)

1.54 City
Population ( c)
17, 589
Per Capita
Wastewater Flow
d)
gallons per
capita per day)
66 2010 0. 705 0. 286 1.45 18, 023 64
2011 0. 724 0. 294 1.57 18, 688 62
2012 0. 781 0. 280 1.71 19, 090 61
2013 0. 919 0. 301 1. 333 19, 642 68
2014 0. 897 0. 315 1. 359 20, 158 67
2015 0. 873 0. 348 L360 20, 796 65
2016 0. 918 0. 405 1. 463 22, 112 66
2017 0. 911 0. 642 1. 553 23, 098 67
2018 1. 046 0. 678 1. 724 24, 124 71
2019 1.04 0. 708 1. 812 25, 332 72
2020 1. 068 0. 831 1. 899 26, 806 71
2021 0. 939 1. 002 1. 941 29, 608 66
2022 1.06 1. 065 2. 171 31, 575 69
Notes:
a) Wastewater flow data from 2009 to 2022 are obtained from the treatment plants' semi- annual monitoring reports. Totals may not sum due to rounding. b) Flows to the CTF includes flows to the Crossroads WWTF prior to its conversion and connection to the CTF in August 2015.
c) City sewered population is assumed to be approximate to City population, which is based on population estimates by the California DOF for the City of Lathrop included in E- 5 Population and Housing Estimates.
d) Per capita wastewater flow is calculated by dividing the total annual wastewater flow by City population and the number of days in a year.
eki environment
water
4-2
December 2024
EKI C20049. 02
353
Section 4
Existing and Future Wastewater Generation
2024 WWSMP Amendment
City of Lathrop
Table 4-2. Current and Historical ADWF and Per Capita ADWF Year
2009
Average Dry
MWQCF
MGD)

0. 701
Weather Flow ( ADWF)
CTF ( b)
MGD)

0. 257
a)
Total
MGD)

1.34 ADWF
vs.

AAF (c)
98%
Annual
Rainfall ( d)
in)

10. 48
Per Capita
ADWF ( e)
gallon per
capita per
day)
64 2010 0. 697 0. 266 1.16 97% 18. 70 62
2011 0. 710 0. 276 1.20 97% 10. 09 60
2012 0. 779 0. 274 1.52 98% 13. 54 60
2013 0. 950 0. 299 1. 358 102% 14. 59 69
2014 0. 896 0. 304 1. 342 99% 14. 23 67
2015 0. 857 0. 335 1. 328 98% 7. 43 64
2016 0. 874 0. 383 1. 405 96% 18. 28 64
2017 0. 97 0. 701 1. 673 108% 16. 60 72
2018 1.0 0. 705 1. 803 105% 14.5 75
2019 1.1 0. 663 1. 771 98% 17. 05 70
2020 1.4 0. 880 2. 020 106% 5. 97 75
2021 0. 97 1. 007 1. 974 102% 14.8 67
2022 1.2 1. 083 2.03 101% 11. 41 70
Notes:
a) ADWF is calculated as the average daily flow between June and August of the year. Totals may not sum due to rounding.
b) Flows to the CTF includes flows to the Crossroads WWTF prior to its conversion and connection to the CTF in August 2015.
c) The ratio of AAF to ADWF is calculated using AAF values from Table 4-1. d) Precipitation data obtained from National Oceanic and Atmospheric Administration Stockton Airport Station ( USW00023237).
e) Per capita ADWF is calculated using City population data in Table 4-1. eki environment
water
4- 3
December 2024
EKI C20049. 02
354
Section 4
Existing and Future Wastewater Generation
2024 WWSMP Amendment
City of Lathrop
Figure 4-1. Current and Historical Wastewater Flow by Collection System

2. 5

2. 0
2 d
U)
Ua
Per
Capita
Wastewater
Generation (
GPCD)
eki

0. 5

0. 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022

CTF- AAF CTF- ADWF MWQCF- AAF MWQCF- ADWF
Figure 4-2. Current and Historical Per Capita Wastewater Flow 80 75
70 65
60 55
50 2008 2010 2012 2014 2016 2018 2020 2022
environment
water
0— Per Capita AAF — • — Per Capita ADWF
4-
December 2024
EKI C20049. 02
355
Section 4 2024 WWSMP Amendment
Existing and Future Wastewater Generation City of Lathrop

4. 2 Wastewater Generation Projections
Wastewater ADWF projections were calculated as the sum of the two major components of future wastewater flow: (1) the volume of wastewater that represents existing wastewater generation within the City in 2022, and ( 2) the anticipated wastewater generation associated with the future development projects and planning areas post 2022. Components of wastewater generation projections are described in the sections below.

4.2. 1 Existing Wastewater Generation
The City' s existing wastewater generation is based on the City' s wastewater flow data in 2022, representing development within the City as of the end of 2022. The City decided to apply a 10% safety factor to the 2022 flows to account for anticipated future increases in I&. A major portion of the City' s collection system consists of the newer systems in the areas west of I-5, which will likely produce more I&in the future as the infrastructure ages.

4. 2. Wastewater Generation Associated with Planned Development Wastewater generation associated with anticipated future development are estimated using land use - specific wastewater flow factors and the anticipated acreages and number of dwelling units associated with each proposed development ( Table 2-1). The land use -specific wastewater flow factors were developed using historic wastewater flow and parcel -level water use data with a safety factor, as described in detail in Appendix A. These factors are developed based on 2017 to 2021 wastewater flows and update those included in the 2019 WWSMP. The updated wastewater generation factors ( in units of gallons per day per dwelling unit or gallons per day per acre; gpd/ du or gpd/ ac) are presented in Table 4-3, below.

Table 4-3. Wastewater Flow Factors
Land Use
Low Density Residential
Wastewater
Historic Lathrop
240 gpd/ du
Flow Factor
West Lathrop
200 gpd/ du
Medium Density Residential 200 gpd/ du 155 gpd/ du
High Density Residential 110 gpd/ du
Commercial 755 gpd/ ac
Industrial 240 gpd/ ac
Parks 55 gpd/ ac
Schools / Institutional 220 gpd/ ac
Table 4- summarizes the volume of wastewater generation associated with anticipated future developments by development area in five- year increments between 2025 and 2045.

4.2. 3 Total Projected Wastewater Generation
Table 4- 5 summarizes the City' stotal projected wastewater generation in five- year increments between 2025 and buildout, as a sum of the existing and new wastewater flow. Based on these projections, it is anticipated that total ADWF in 2045 will be 5. 67 MGD. Of these totals, ADWFs of 1. 36 MGD and

4. 31 MGD are anticipated to flow to MWQCF and the Lathrop CTF, respectively. The majority of the anticipated increase in wastewater generation at the CTF is associated with the River Islands and Central Lathrop development areas.
eki environment
water
4-5
December 2024
EKI C20049. 02
356
Section 4
Existing and Future Wastewater Generation
2024 WWSMP Amendment
City of Lathrop
Table 4-
Projected New Wastewater Flow by Development Area
Land Use Designation
Central Lathrop Phase 1
Wastewater
Flow Factor
Projected New Wastewater Flow (gpd) (a)
2025 2030 2035 2040 Buildout 2045
Low Density Residential
High Density Residential
240 gpd/ du
110 gpd/ du
0 0
120, 00

27. 060
183, 360
50, 160
183, 360
63,90
183, 360
63,90
Commercial 755 gpd/ ac 9, 815 55,38 55,38 55,38 109, 88 Mixed Use 755 gpd/ ac 0 0 0 0 38, 505
Parks 55 gpd/ ac 0 2, 149 2, 424 2, 424 2, 424
New Central Lathrop ADWF 9, 815 204, 77 291, 482 305, 012 397, 87 Central Lathrop - Phase 2
Light Industrial / R&D Flex 240 gpd/ ac 21, 557 21, 557 21, 557 21, 557 163, 620 Parks 55 gpd/ ac 0 0 0 0 275
New Central Lathrop ADWF 21, 557 21, 557 21, 557 21, 557 163, 895 Mossdale Landing
Low Density Residential 240 gpd/ du 0 0 0 0 15, 840
Medium Density Residential 200 gpd/ du 0 0 0 0 0
High Density Residential 110 gpd/ du 0 0 0 0 0
Commercial 755 gpd/ ac 3, 443 4, 575 4, 575 4, 575 4, 575 Schools 220 gpd/ ac 0 0 0 0 3, 573
New Mossdale ADWF 3, 443 4, 575 4, 575 4, 575 23, 988
Mossdale Landing East
Low Density Residential 240 gpd/ du 0 8,80 8,80 8,80 8,80 High Density Residential 110 gpd/ du 0 0 0 0 9, 240
Commercial 755 gpd/ ac 0 5, 285 5, 285 5, 285 5, 285
New Mossdale ADWF 0 14,65 14,65 14,65 23, 405
Mossdale Landing South
Medium Density Residential 200 gpd/ du 17, 000 17, 000 17, 000 17, 000 17, 000 Commercial 755 gpd/ ac 0 0 6, 040 6, 040 18, 875
Parks 55 gpd/ ac 0 220 220 220 220
New Mossdale ADWF 17, 000 17, 220 23,60 23,60 36, 095
Mossdale Landing West
Low Density Residential 240 gpd/ du 0 0 198, 960 198, 960 198, 960 Parks 55 gpd/ ac 0 0 603 603 603
New Mossdale ADWF 0 0 199, 563 199, 563 199, 563
River Islands
Low Density Residential 200 gpd/ du 153, 600 397, 200 640, 80 884, 400 884, 400 Medium Density Residential 155 gpd/ du 104, 780 251,55 397, 730 544, 205 544, 205 High Density Residential 110 gpd/ du 0 153, 450 306, 900 460, 350 460, 350 Town Center 755 gpd/ ac 0 19, 857 39, 713 59,70 59,70
Commercial 755 gpd/ ac 0 65, 006 130, 011 195, 017 195, 017 Schools 220 gpd/ ac 7, 150 10, 450 13, 750 16, 830 16, 830 Parks 55 gpd/ ac 1, 045 4, 395 7,50 11,05 11,05
New River Islands ADWF 266, 575 901, 62 1, 536, 654 2, 171, 476 2, 171, 476 South Lathrop
Light Industrial / R&D Flex 240 gpd/ ac 0 16, 080 16, 080 16, 080 23, 940 Office Commercial 755 gpd/ ac 0 6,44 6,44 6,44 7, 550
Open Space 55 gpd/ ac 0 0 0 0 0
New South Lathrop ADWF 0 22, 724 22, 724 22, 724 31, 490 Lathrop Gateway
Light Industrial / R&D Flex 240 gpd/ ac 0 15, 840 15, 840 19, 824 19, 824 Office Commercial 755 gpd/ ac 0 38, 505 38, 505 47, 339 47, 339 Open Space 55 gpd/ ac 0 138 138 226 226
eki
New Lathrop Gateway ADWF
environment
water
0 54A83 54, 483 67, 388 67, 388
December 2024
EKI C20049. 02
357
Section 4
Existing and Future Wastewater Generation
2024 WWSMP Amendment
City of Lathrop
Table 4-
Projected New Wastewater Flow by Development Area
Land Use Designation
Wastewater Projected New Wastewater Flow (gpd) (a)
Flow Factor
2025 2030 2035 2040 Buildout2045
Crossroads
Industrial 240 gpd/ ac 0 5,20 5,20 5,20 5,20
Commercial 755 gpd/ ac 0 1,33 1,33 1,33 1,33
New Crossroads ADWF 0 6,53 6,53 6,53 6,53
Historic Lathrop and Other Development Areas
Low Density Residential 240 gpd/ du 0 2, 880 4, 320 5,20 12, 480 Medium Density Residential 200 gpd/ du 5, 400 10, 600 15, 800 21, 000 43, 600 High Density Residential 110 gpd/ du 0 0 0 0 5, 280
Commercial 755 gpd/ ac 16, 610 26, 878 26, 878 26, 878 32, 918 Industrial 240 gpd/ ac 4, 320 4, 320 4, 320 4, 320 10, 080 New Historic Lathrop / Other ADWF 26, 330 44, 678 51, 318 57, 718 104, 358 Sharpe Army Depot
Industrial I -- 32, 000 32, 000 32, 000 32, 000 32, 000 New Sharpe Army Depot ADWF 32, 000 32, 000 32, 000 32, 000 32, 000 Total Projected New ADWF 376, 720 1, 324, 413
PROJECTED NEW ADWF AT CTF 318,90 1, 247, 735
PROJECTED NEW ADWF AT MWQCF 58, 330 76, 678
2,58, 433 2, 926, 091 3, 258, 188
2, 175,15 2, 836, 373 3, 121, 830
83, 318 89, 718 136, 358
Notes:
a) Projected residential wastewater generation calculated as the total number of projected residential dwelling units multiplied by the applicable wastewater flow factor (Table 4-3). Projected non- residential wastewater flow are calculated as the total projected acreage multiplied by the applicable wastewater flow factor ( Table 4-3). Projected residential dwelling units and non- residential acreage are listed in Table 2-1. eki environment
water
December 2024
EKI C20049. 02
358
Section 4
Existing and Future Wastewater Generation
2024 WWSMP Amendment
City of Lathrop
Table 4-5. Existing and Future Wastewater Flow by Development Area Wastewater Generation ( MGD) (a)
Development Area (a) Baseline Buildout
2025 2030 2035 2040
b) 2045
Lathrop CTF
Central Lathrop and
Mossdale ( c)

0. 46 0. 51 0. 73 1. 02 1. 03 1. 31
River Islands 0. 44 0. 71 1. 35 1. 98 2. 62 2. 62
South Lathrop 0.02 0.02 0.25 0.25 0.25 0.34
Lathrop Gateway and
Crossroads ( c)

0. 28 0. 28 0. 34 0. 34 0. 36 0. 36
ADWF at CTF 1.9 1. 51 2. 44 3.7 4. 03 4. 31
Manteca
Historic Lathrop and Other
Development Areas

1. 22 L28 1. 30 1. 30 1. 31 1. 36
ADWF at MWQCF 1. 22 1. 28 1. 30 1. 30 1. 31 1. 36
TOTAL EXISTING ADWF ( b) 2. 41 2. 79 3. 73 4. 67 5. 34 5. 67 Notes:
a) Projected wastewater generation calculated as the sum of baseline wastewater generation and the incremental new wastewater generation associated with future development shown in Table 4-. b) Baseline wastewater generation is based on the existing wastewater generation in 2022 at 2. 12 MGD with a 10% factor of safety to account for future I&.
c) Development areas served by the Lathrop CTF are grouped due to the availability of existing pump station flow data. Central Lathrop and Mossdale ADWF is estimated using flow from the Mossdale PS. Crossroads and Lathrop Gateway ADWF are estimated as the LCTF flow minus flow from the River Islands, Mossdale, and South Lathrop pump stations.
d) Totals may not sum due to rounding.
eki environment
water
4-8
December 2024
EKI C20049. 02
359
Section 4 2024 WWSMP Amendment
Existing and Future Wastewater Generation City of Lathrop

4. 3 Wastewater Peaking Factors
EKI reviewed the City' s historical wastewater flow data between 2017 and 2022 to verify and update the peaking factor curve that best estimates PWWF. PWWF is the highest hourly flow experienced during the year due to rainfall -induced I&and peak diurnal sanitary flows and is used to evaluate the hydraulic capacity of a wastewater collection system. The PWWF peaking factors are typically higher in smaller drainage areas, in which there is little flow attenuation. Larger drainage areas provide a greater capacity to attenuate flows, as peak flows generated in the upstream reaches of the system take a longer
amount of time to travel downstream. EKI developed a new peaking factor curve shown on Figure 4-3.

The methodologies used to develop this curve are described in Appendix B.

Figure 4-3. Average Dry Weather Flow and Peaking Factors 6 0
eki
Peaking Factor = e(- 3. t"ADWF( MGD)+ 0.9) + 2. 05
0 environment
water
500, 00 1, 000,00 1, 500, 000
Average Dry Weather Flow ( gpd)
4- 9
2, 000,00
December 2024
EKI C20049. 02
360
Section 5 2024 WWSMP Amendment
Wastewater Treatment Capacity Assessment City of Lathrop 5 WASTEWATER TREATMENT CAPACITY ASSESSMENT
This section compares the City' s projected wastewater generation through 2045 to its treatment capacity at the two treatment plants. The City' s collection system and treatment plant capacity are described in Section 3. 2.

5. 1 Wastewater Treatment Capacity Assessment
Table 5-1 and Figure 5-1 compares the projected ADWF with the City' s allocation at 1. 451 MGD at the MWQCF ( Section 3. 2.1). The City' s allocation at the MWQCF is sufficient to meet projected wastewater flows to the MWQCF through buildout.

As shown in Table 5-2 and on Figure 5-2, flows to the Lathrop CTF is anticipated to exceed the current CTF capacity of 2. 5 MGD between 2030 and 2035. The City anticipates completing the Lathrop CTF Phase 3 Expansion within the next three years to meet the projected wastewater flows. The Phase 3 Expansion will expand the CTF' s capacity to a total of 5. 0 MGD, which is sufficient to meet projected flows through buildout.

Collectively, wastewater treatment capacity at the CTF ( including the Phase 3 Expansion) and MWQCF is projected to be sufficient to meet Citywide projected wastewater flows through buildout ( Table 5- 3 and Figure 5-3). However, as discussed below in Section 5. 2, recent increases in wastewater strength observed at the treatment plants may limit their treatment capacities. eki environment
water
5-1
December 2024
EKI C20049. 02
361
Section 5
Wastewater Treatment Capacity Assessment
2024 WWSMP Amendment
City of Lathrop
Table 5-1. Projected Wastewater Flow and Treatment Capacity at MWQCF Estimated ADWF Influent and Treatment Capacity ( MGD)
Existing
2022)
2025 2030 2035 2040 2045
Projected Influent ADWF (a)
ADWF Projection 1.1 1. 28 1. 30 1. 30 1. 31 1. 36
MWQCF Capacity
Allocated Capacity 1. 451 1. 451 1. 451 1. 451 1. 451 1. 451 Projected Deficit
Notes:
a) Wastewater influent to MWQCF is the wastewater flow from the Historic Lathrop area and Sharpe Army Depot.

Wastewater
Flow /
Treatment
Capacity (
MGD)

1. 6

1. 4

1. 2

1. 0

0. 8

0. 6

0. 4

0. 2

0. Figure 5-1. Projected Wastewater Flow and Treatment Capacity at MWQCF Existing ( 2022) 2025 2030 2035 2040 2045
ek, environment
water
Emil Allocated Capacity — 1r—ADWF Projection
5- 2
December 2024
EKI C20049. 02
362
Section 5
Wastewater Treatment Capacity Assessment
2024 WWSMP Amendment
City of Lathrop
Table 5-2. Projected Wastewater Flow and Treatment Capacity at Lathrop CTF Estimated ADWF Influent and Treatment Capacity ( MGD)
Existing
2022)
2025 2030 2035 2040 2045
Projected Influent ADWF ( a)
ADWF Projection 1. 08 1. 51 2. 44 3.7 4. 03 4. 31
Existing Capacity and Future Expansions
Lathrop CTF Phase 0 - 2 ( b) 2. 50 2. 50 2. 50 2. 50 2. 50 2. 50 Lathrop CTF Phase 3 0.0 0.0 2. 50 2. 50 2. 50 2. 50
Total Capacity 2. 50 2. 50 5. 00 5. 00 5. 00 5. 00
Projected Deficit
Notes:
a) Wastewater influent to Lathrop CTF is the combination of wastewater flow from all city areas except for the Historic Lathrop area and Sharpe Army Depot.
b) Higher influent wastewater nutrient concentrations recently observed at the CTF may limit its hydraulic capacity to approximately 2. 0 MGD ( see Section 5.2).

Wastewater
Flow /
Treatment
Capacity (
MGD)

6. 0

5. 0

4. 0

3. 0

2. 0

1. 0

0. eki
Figure 5-2. Projected Wastewater Flow and Treatment Capacity at Lathrop CTF Existing ( 2022) 2025 2030 2035 2040 2045
Lathrop CTF Phase 0 - 2
environment
water
Lathrop CTF Phase 3 Lathrop CTF ADWF Projection
5-3
December 2024
EKI C20049. 02
363
Section 5
Wastewater Treatment Capacity Assessment
2024 WWSMP Amendment
City of Lathrop
Table 5-3. Projected Wastewater Flow and Treatment Capacity, Citywide Estimated ADWF Influent and Treatment Capacity ( MGD)
Existing
2022) 2025 2030 2035 2040 2045
Projected Influent ADWF (a)
Total ADWF Projection 2. 19 2. 79 3. 73 4. 67 5. 34 5. 67 Existing Capacity and Future Expansions
Manteca WQCF 1. 451 1. 451 1. 451 1. 451 1. 451 1. 451
Lathrop CTF Phase 0 - 2 2. 50 2. 50 2. 50 2. 50 2. 50 2. 50 Lathrop CTF Phase 3 0.0 0.0 2. 50 2. 50 2. 50 2. 50
Total Capacity 3. 95 3. 95 6. 45 6. 45 6. 45 6. 45
Projected Deficit

7. 0

6. 0
2 Y
a 5. 0
v

4. 0
a)
a

3. 0
LL
w 2. 0
f6
co 1. 0
o.

Figure 5-3. Projected Wastewater Flow and Treatment Capacity, Citywide Existing ( 2022) 2025 2030 2035 2040 2045
Manteca WQCF MEI Lathrop CTF Phase 0 - 2
Lathrop CTF Phase 3 -*- Total ADWF Projection
kienvironment water
5-4
December 2024
EKI C20049. 02
364
Section 5 2024 WWSMP Amendment
Wastewater Treatment Capacity Assessment City of Lathrop

5. 2 Impacts of Wastewater Strength on Treatment Capacity Both the MWQCF and the Lathrop CTF are observing increasing influent wastewater strength ( i.e. concentration of pollutants and nutrients in wastewater) likely due to improved water use efficiency during the recent droughts and in response to state regulations. The increases in influent wastewater strength may further limit treatment capacities at the treatment plants.

5. 2. 1 Manteca Water Quality Control Facility
In March 2022, Stantec Consulting Services ( Stantec) and Herwit Engineering ( Herwit) completed a MWQCF Capacity Study that indicates a reduction in MWQCF treatment capacity due to increased wastewater strength over recent years among other factors. To review the pollutant concentration in Lathrop' s wastewater conveyed to the MWQCF, EKI conducted monitoring study during October 2022, summarized in Appendix C.

The current wastewater influent to MWQCF, including flows from the Cities of Lathrop and Manteca, has an average BOD concentration of 372 mg/ L over the period of 2016 to 2021 ( Stantec and Herwit, 2022). To investigate the contribution of wastewater strength, EKI performed monitoring of flow and BOD, TSS, and total kjeldahl nitrogen ( TKN) concentrations during October 2022 at selected locations in the City' s wastewater collection system connected to the MWQCF. The results indicate there was relatively little variation in BOD, TSS, and TKN concentrations across the six monitored locations. 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 MWQCF, however, the TSS concentrations in the collection system were generally significantly lower than the concentrations from MWQCF samples. BOD concentrations in the collection system samples ranged from 208 mg/ Lto 312 mg/ L. A summary of sampling results is detailed in Appendix C.

5.2. Lathrop Consolidated Treatment Facility
The current capacity of the Lathrop CTF at 2. 5 MGD was designed in 2015 based on a pollutant loading of 420 mg/ L BOD ( carbon) and 60 mg/ Ltotal nitrogen (TN) (nitrogen). However, current sewer flows to the CTF contain higher dissolved and particulate BOD and TN concentrations. In its 2021 sewershed analysis, PACE Engineers ( PACE) showed an increase of 15 to 20% in pollutant load per gallon of water or hydraulic load in wastewater samples collected in the Mossdale, River Islands, and Crossroads areas compared to the CTF design concentrations ( PACE 2021). The higher pollutant loading limits the treatment capacity and reduces the CTF hydraulic capacity to 2. 0 MGD at current pollutant loading conditions ( PACE, 2021).

In the City' s collection system draining to the Lathrop CTF, PACE conducted sampling and analysis of BOD and TN during August of 2021. Samples were collected from four locations including Mossdale, River Islands, Crossroads, and combined CTF influent. Filtered chemical oxygen demand ( COD), TN, and total dissolved solids ( TDS) were analyzed for each sample and BOD was estimated from COD / filtered COD. The average BOD for the Mossdale, River Islands, Crossroads, and combined CTF locations were 554. 2mg/ L, 466. 8mg/ L, 544. 3mg/ L, and 355. 8mg/ L, respectively ( PACE, 2021). 3 3 PACE indicated that the results for the combined CTF influent were artificially low due to the auto -sampling equipment being located too far from the sample location and treatment occurring within the sample tubing. eki environment
water
5-
December 2024
EKI C20049. 02
365
Section 6 2024 WWSMP Amendment
Collection System Performance and Design Criteria City of Lathrop 6 COLLECTION SYSTEM PERFORMANCE AND DESIGN CRITERIA
The criteria used to evaluate the City' s existing collection system is based on 2022 Lathrop Design and Construction Standards (" Standards"; Lathrop, 2022) and the 2019 WWSMP. A summary of the wastewater system design criteria is provided below:

For hydraulic analyses, a Manning' s "n" of 0.13 is assumed for all sewers.

Pipes 15 inches in diameter and smaller are designed for peak flows with a maximum depth to diameter ( d/ D) ratio of 0. 50. Pipes 18 inches in diameter and larger are designed for peak flows at a maximum d/ D ratio of 0. 75.

Design velocity and head loss for force mains calculated using Hazen - Williams formula with a roughness constant of 110.

Minimum velocity greater than 2 feet per second ( fps) for pipes flowing half full.

Minimum gravity main slopes are summarized in Table 6-1.

Maximum velocity less than 10 fps.

Pump stations should be designed to convey PWWF within its firm capacity'.

Table 6-1. Minimum Gravity Main Slopes
Pipe Size ( inch)
6 Minimum Slope (ft/t)

0.050
8 0.035
10 0.025
12 0.020
15 0.015
18 0.012

6. 1 Capacity Criteria
The collection system is primarily evaluated against its ability to carry projected PWWF. Specifically, the d/ D ratio for gravity mains under PWWF are compared to the design criteria. Force mains are considered to be capacity deficient if maximum velocity exceeds 10 fps. For pump stations, the required total head and flow under PWWF are compared to their firm capacity.

6. 2 Minimum Velocity and Slope Criteria
Minimum velocity and slope criteria for gravity mains are of the same nature and independent of flow, i.e. velocity in a pipe flowing at half full is determined by its slope. These criteria ensure an appropriate flushing velocity and prevents sediment buildout in the pipes. However, it is unnecessary to correct an existing pipe with a mild slope if the pipe is sufficient to carry PWWF. The minimum velocity and slope criteria evaluation were not updated as part of this WWSMP Amendment. 4 Defined as pumping capacity with the largest pumping unit out of service. ek, environment
water
6- 1
December 2024
EKI C20049. 02
366
Section 7 2024 WWSMP Amendment
Hydraulic Assessment of the Collection System City of Lathrop 7 HYDRAULIC ASSESSMENT OF THE COLLECTION SYSTEM
EKI updated the City' s wastewater system hydraulic model to assess the ability of City' s existing collection system and key planned infrastructure under various wastewater flow scenarios to meet the recommended performance and operational criteria described in Section 6. A hydraulic model transforms information about the physical facilities and system into a mathematical model used to analyze the sewer system under various demand conditions. The hydraulic model then generates information on flow, velocity, flow depth, and head 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 hydraulic design criteria, EKI ( 1) conducted steadystate model simulations of PWWF conditions, and ( 2) evaluated capacity and head requirements at PWWF for each lift station or pump station for existing and buildout scenarios.

The PWWF were modeled for all pipes as the total ADWF upstream of the pipe multiplied by the corresponding peaking factor from Figure 4-3. Pump stations were first modeled as ideal pumps that can pump at a rate equal to the inflow to determine the estimated PWWF influent to each pump station.

The modeling results were then evaluated against actual pump hydraulics to determine if each pump station has sufficient capacity to pump the modeled PWWF.

7. 2 Hydraulic Model Update
This section provides an overview of the updates to the City' ssewer system hydraulic model as part of this WWSMP amendment.

7. 2. 1 Model Platform
The City' s existing sewer system hydraulic model was developed on the Innovyze InfoSWMM model platform for the 2019 WWSMP. This selection was partially based on the platform' s geographical information system ( GIS) integration capabilities. To optimize the modeling building and maintenance process, a key objective of the IWRMP modeling effort was to construct hydraulic models that are integrated with the City' sinfrastructure GIS and allow for automatic synchronization between the model and infrastructure GIS to limit future maintenance efforts.

7. 2. Model Update
The City maintains a GIS geodatabase of its infrastructure assets, which was used as the basis of information to construct the existing water system hydraulic model. EKI updated the City' s GIS database
to incorporate recent infrastructure improvements, identified and filled data gaps to make sure the GIS database accurately represented the City' s existing utility infrastructure as of January 2023.

After importing the City' sGIS data into the hydraulic model, the following steps are performed to address data gaps, validate network data, and create a fully connected network:

New wastewater system infrastructure, including lift stations, pipeline improvements constructed post 2019 WSMP, were digitized in the geodatabase and incorporated into the new hydraulic model.
ekienvironment water
7-1
December 2024
EKI C20049. 02
367
Section 7 2024 WWSMP Amendment
Hydraulic Assessment of the Collection System City of Lathrop The model network was reviewed and refined for connectivity. Using the software' stools, each pipe was connected to a model nodes and identified for upstream and downstream directions.

Orphan and duplicate elements were corrected.

Node and pipe invert data were reviewed and corrected for data errors. Missing invert data were inferred based on the City' s
minimum slope requirement, known invert of connecting
pipes, and ground slope.

Global parameters including Manning' sconstant and the Hazen - Williams C -Factors were applied to pipes based on City' s design criteria.

All scenarios were created with associated active facilities and conveyance configurations Parcel -level wastewater flow projections were allocated to the nearest upstream manhole.

EKI also obtained data for pump stations including wet well dimensions and elevations, pump types, operating levels, and head -discharge curves. These data are summarized in Table 3- 2 and are the basis for the pump station evaluation in Section 7. 5. Modeled PWWF at each pump station are summarized in Table 7-1.

EKI did not recalibrate the hydraulic model due to lack of sewer flow monitoring data. However, flow monitoring recommended as a CIP ( see Section 8) could be used to calibrate the model in the future.

7. 3 Sewer System Hydraulic Modeling Scenarios
The Existing ( 2022) and Buildout ( 2045) scenarios respectively assess existing infrastructure and regional infrastructure needs for the City' scurrent and planned developments described in Section 2.

Parcel - level wastewater ADWFs for the existing scenario were developed based on parcel land use and wastewater generation factors summarized in Section 4.2. Future ADWF included in the Buildout scenario is consistent with flow projections described in Section 4.2.3. Figure 7-1 shows parcels and future development included in each scenario.
s
either a manhole, a force main fitting, or a network structure ek, environment
water
7- 2
December 2024
EKI C20049. 02
368
Section 7
Hydraulic Assessment of the Collection System
2024 WWSMP Amendment
City of Lathrop
Table 7-1. Peak Wet Weather Flow at Pump Stations.

Existing Buildout
Lift Station or Pump Station
ADWF Peaking PWWF ADWF Peaking PWWF
mgd) Factor ( mgd) ( mgd) Factor ( mgd)
MWQCF Collection System
North Harlan PS 0.17 4. 0.76 0.40 4. 2 0. 168
Stonebridge LS 0. 158 3. 6 0. 561 0. 158 3. 6 0. 561
Woodfield LS 0. 382 2. 8 1. 071 0. 389 2. 8 1. 083
Valley Crossing LS 0.09 4. 0.39 0.09 4. 0.39
J Street LS 0. 270 3. 1 0. 842 0. 315 3. 0 0. 938
Easy Court LS 0.81 4. 0 0. 322 0.83 4. 0 0. 327
O Street PS 0. 518 2. 5 1. 317 0. 583 2. 5 1. 431
McKinley Avenue PS 0. 564 2. 5 1. 398 0. 575 2. 5 1. 417 Lathrop CTF Collection System
Central Lathrop PS 0.69 4. 0 0. 279 0. 630 2. 4 1. 511
Mossdale PS 0. 579 2. 5 1. 424 0. 861 2. 1. 913
River Islands 2A PS 0. 183 3. 4 0. 629 1. 395 2. 1 2. 905 River Islands Main PS 0. 493 2. 6 1. 273 2. 658 2. 1 5. 45 Crossroads PS 0.43 4. 2 0. 182 0.54 4. 1 0. 223
South Lathrop PS 0.003 4. 5 0.01 0.32 4. 3 0. 136
Lathrop Gateway PS 0.1 4. 5 0.3 0.7 4. 0 0. 286
Notes:
a) Flow information is not available for the Louise Avenue PS. eki environment
water
7-3
December 2024
EKI C20049. 02
369
f,egendSphere of Influence
Development Areas
Central Lathrop
QCrossroads
f
Historic Lathrop Infill and Other Developments
OLathrop Gateway
Mossdale Landing
Mossdale Landing East
Mossdale Landing West
Mossdale Landing South
River Islands
Sharpe Army Depot
Q South Lathrop
Incremental Development by Model Scenario
Itat Existing ( 2022)
Buildout ( Beyond 2040)
Notes

1. All locations are approximate.

Sources

1. Aerial photograph provided by ESRI' s ArcGIS Online, 16 January 2024.

NA
4, 000 8, 000
Scale in Feet)
Modeling Scenarios
Wastewater System Master Plan Amendment
Coy of Lathrop
Lathrop, CA
December2024
Ienvironment 02004901
water Figure 7- 1
370
Section 7
Hydraulic Assessment of the Collection System City of Lathrop 2024 WWSMP Amendment

7. 4 Collection System Hydraulic Evaluation
As discussed in Section 6.1, the City' scollection system is primarily assessed against the capacity criteria, including d/ D ratio in gravity mains and maximum velocity in force mains. Figure 7-2 and Figure 7-3 show the modeled d/ D ratio under PWWF for each scenario. Gravity mains are highlighted where the modeled d/ D ratio exceeds the design criteria.

Modeled results are generally similar to the 2019 WWMP update and show that approximately 3% of City' s existing gravity mains will not meet the capacity criteria by 2045 ( see Table 7-2). As shown on Figure 7-2 and Figure 7-3, areas with capacity deficiencies are mostly consistent in the two scenarios, indicating that most capacity deficiencies identified in the Buildout scenario already exist in the existing system, although the degree of deficiency may increase with projected development.

Table 7- 2 summarizes modeled d/ D ratio results for each scenario.

Table 7-2. Summary of Collection System Capacity Deficiencies Scenario
Percent Length of Gravity Mains
Meeting
Capacity
Criteria
d/ D Ratio
Greater
Than 0. 5
a)
d/ D Ratio
Greater
Than 0. 75
d/ D Ratio
Greater Than 1
Surcharged)
Existing 98% 1.4% 0.1% 0.2%
Buildout 97% 2.0% 0.2% 0.3%
Notes:
a) Gravity mains less than 18 -inch diameter and exceeding the capacity criteria. eki environment
water
7-5
December 2024
EKI C20049. 02
371
Stanford Cro5sing. PS
Mossdale S1
Valley Crossings LS

DE LIMA RD

DOS REIS RD
N
Harlaorthn PS
I
j
1 r
i
PS
Easy Ct LS
0 St. PS
Crossroads PSG
Stonebridge PS
Sharp+ Private)
Lathrop CTF
Woodfield Li

LATHROP RD
California
i Natural Prodjcts
PS ( Private) I
McKinley l
Ave PS
EouiseAvePS
I

LOUISE AV
SSI PS
su( F
ivate)
Lathrop
Gateway PS
outh4ethrop PS

LIP LSI
Private)
i I YOSEMITE AV
MWQCFFFlow Meter
MWQCF
environment
water
fL, egendSphere of Influence
OApproximate Area of WWTF
Pump Station or LA Station
Force Main
Gravity Mains
Meeting Capacity Criteria
Modeled Deficiencies
d/ D ratio 0. 51 - 0. 75
d/ D ratio 0. 76 - 0. 99
d/ D ratio >= 1. 0 (Surcharged)
Abbreviations
CTF = Consolidated Treatment Facility
d/ D = flow depth vs. pipe diameter
LIP = Lathrop Industrial Park
LS = lift station
MWQCF = Manteca Water Quality Control Facility
PS = pump station
SSI = Super Store Industries
WWTF = wastewater treatment facility
Notes

1. All locations are approximate.

Sources

1. Aerial photograph provided by ESRI' s ArcGIS Online, 12 March 2024.

N
0 2, 000 0.00
Sao u Fat)
Existing Collection System Capacity Deficiencies
Wastewater System Master Plan Amendment
Cry or LeMrop
Lathrop, CA
December 2024
C20040 02
Figure 7- 2
372
River Islands P
Stanford Crossing. PS
UF
Mossdale PS. (;
r•• ,-\Y\\\, yam\
River Islands
Main PS
Valley Crossings LS

DE LIMA RD

DOS REIS RD
Ili`
Crossroads PS
i
North
Harlan PS
t
PS
Easy Ct LS
O St. PS
Stonebridge PS !
SharpelPS Private)
Woodfield Li

LATHROP RD
1 -California
Natural Prod cts
i
PS ( Private)
McKinley
Ave PS
Louise Ave PS

ILOUISE AV
SSI PS
a( PPivate)
Lathrop CTF
Lathrop
Gateway PS
Soyitheathrop PS

LIP LS(
Private)
i I
tOSEMITE AV
MWQCFFFlow Meter
MWQCF
ekenvironment 1 & water
r.egendSphere of Influence
nApproximate Area of WWTF
90 Pump Station or Lift Station
Force Main
Gravity Mains
Meeting Capacity Criteria
Modeled Deficiencies
d/ D ratio 0. 51 - 0. 75
d/ D ratio 0. 76 - 0. 99
d/ D ratio >= 1. 0 (Surcharged)
Abbreviations
CTF = Consolidated Treatment Facility
d/ D = flow depth vs. pipe diameter
LIP = Lathrop Industrial Park
LS = lift station
MWQCF = Manteca Water Quality Control Facility
PS = pump station
SSI = Super Store Industries
WWTF = wastewater treatment facility
Notes

1. All locations are approximate.

Sources

1. Aerial photograph provided by ESRI' s ArcGIS Online, 28 March 2024.

N o 2, 600 5, 000
SUM In FM)
Buildout Collection System Capacity Deficiencies
Wastewater System Master Plan Amendment
City of Lathrop
Lathrop, CA
December 2024
C20040 O2
Figure 7-3
373
Section 7 2024 WWSMP Amendment
Hydraulic Assessment of the Collection System City of Lathrop

7. 5 Force Main and Pump Station Capacity Evaluation
The hydraulic requirements at each lift station or pump station depend on configuration of its downstream force main, specifically, size and head loss. Therefore, EKI ran the model and reviewed the resulting velocities to optimize force main configuration in the Buildout scenario before conducting the hydraulic assessment.

Table 7-3 summarized the force main configurations under PWWF in each scenario, as well as the head loss and velocity of each force main. As shown on the table, the City' s existing and planned force mains are able to convey projected wastewater flow through buildout.

Table 7-4 summarizes the flow and total head requirements under PWWF for each pump station. The table also lists the firm capacities of each pump station under Existing and Buildout scenarios, which may be affected by a pump station expansion or significant change in the total head requirement due to development. When compared to the pump stations' capacities, deficiencies are identified in the Stonebridge LS in both scenarios.
eki environment
water
7-8
December 2024
EKI C20049. 02
374
Section 7
Hydraulic Assessment of the Collection System
2024 WWSMP Amendment
City of Lathrop
Table 7-3. Force Main Hydraulic Analysis Results
Upstream Pump Station
Force Main
Diameter
in)
Existing Buildout
Velocity Velocity
fps)( b) ( fps)( b)

CLSP PS
18 14" Capacity Sufficient ( b)
14 0. 40 2. 14
Mossdale PS
8 1. 60 1. 75
12 2. 05 2.4
River Islands 2A 30 1. 89 2. 57
River Islands Main PS
18 1. 09 3. 45
12 18" Capacity Sufficient ( b) 2. 71
Crossroads PS 8 1. 21 1. 44
South Lathrop PS
6 0. 10 0. 53
6 6" Capacity Sufficient ( c)
Lathrop Gateway PS
6 0. 68 2. 39
4 6" Capacity Sufficient ( c)
North Harlan PS 6 0. 59 1. 31
Stonebridge PS 6 4. 36 4. 36
Woodfield LS 10 2. 98 3. 02
Valley Crossings LS 4 0. 98 0. 98
J St. PS 8 4. 10 4.7
Easy Ct LS 8 2. 32 2. 33
O St. PS 12 2. 55 2. 76
McKinley Ave PS 10 5. 44 5. 47
Notes:
a) Blue bolded text indicates velocity does not meet minimum criteria of 2 fps. b) Velocity in the force mains under steady- state hydraulic modeling is evaluated as a secondary criterion. In reality, force main and pump station operations can be adjusted from time -to -time to ensure there is enough velocity to prevent sedimentation.
c) For pump stations with parallel force mains, a single force main was modeled when velocities were below 2 fps.
eki environment
water
7- 9
December 2024
EKI C20049. 02
375
Section 7
Hydraulic Assessment of the Collection System
2024 WWSMP Amendment
City of Lathrop
Table 7-4. Summary of Hydraulic Capacity Analysis for Pump Stations Existing
Existing Scenario Buildout
Buildout Scenario
Firm
Firm
Pump Station
Capacity
Capacity
gpm)
PWWF TDH ( gpm) PWWF TDH
gpm) ( ft) ( b) ( gpm) ( ft)
MWQCF Collection System
North Harlan PS 1, 075 53 11. 4 117 21.

Stonebridge LS 350 390 47. 5 390 43. 0
Woodfield LS 820 744 47. 5 752 50. 2
Valley Crossing LS ( c) 83 27 47. 5 27 50. 2
J Street LS 700 584 27. 8 651 28. 1
Easy Court LS 500 223 37. 9 227 65. 1
O Street PS 2, 800 915 27. 8 994 28. 1
McKinley Avenue PS 1, 675 971 34. 1 984 35. 5
Lathrop CTF Collection System
Stanford Crossing PS 2, 300 194 37. 9 1, 049 65. 1
Mossdale PS 4, 050 989 43. 2 3, 450 1, 328 58. 9
River Islands 2A PS 3, 975 437 19. 4 2, 018 19. 9
River Islands Main PS ( e) 1, 700 884 37. 9 15, 000 3, 785 65. 1 Lathrop Gateway PS 280 126 13. 5 155 22.

South Lathrop PS 1, 850 1 27. 8 94 28. 1
Notes:
a) Red bolded text indicates PWWF exceeded pump station' s firm capacity. b) If different from existing firm capacity.
c) Capacity of the 8" outlet is listed as the lift station capacity, as it is the capacity limiting component of this pump station.
d) Flow information is not available for the Louise Avenue PS, therefore, its capacity is not analyzed. e) It is anticipated that the River Islands Sewer PS will be constructed in phases to include a total of six pumps.
eki environment
water
7- 10
December 2024
EKI C20049. 02
376
Section 8 2024 WWSMP Amendment
Capital Improvement Program Changes to the 2019 WWSMP City of Lathrop 8 CAPITAL IMPROVEMENT PROGRAM CHANGES TO THE 2019 WWSMP This section recommends modifications and additions to the list of recommended CIPs included in the 2019 WWSMP and the City' s current Capital Improvement Program ( Lathrop, 2023). Table 8- 1 summarizes the current CIPs and incorporates the modifications recommended herein. The Opinion of Probable Cost ( OPC) for each project is escalated to December 2024 dollars based on an Engineering News Record ( ENR) Construction Cost Index ( CCI) of 13, 632 (20 -city average). The OPCs are conceptual level estimates, 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.

Figure 8- 1 shows an overview of the collection system project locations and improvements. Each project is shown in detail in Appendix D .

8. 1 Modifications to Wastewater Treatment CIPs
The following modifications to the City' s wastewater treatment CIPs are identified to reflect recent wastewater strength at MWQCF and the City' s progression on CTF expansions.

8. 1. Manteca Interim Improvements
As discussed in Section 5. 1, the City of Manteca indicated that increases in influent wastewater nutrient concentrations reduce MWQCF' streatment capacity to 6. 36 MGD and, therefore, Lathrop' sshare of MWQCF' scapacity to 0. 935 MGD ( Stantec and Herwit, 2022; Manteca, 2022). The City' s ADWF
conveyed to the MWQCF was 1.1 MGD in 2022 and was above this estimated reduced allocation.

Moreover, the City anticipates a total of 1. 31 MGD of wastewater will flow to MWQCF at buildout.

The City of Manteca is planning interim improvement projects which would increase the MWQCF' s capacity to 8. 23 MGD and Lathrop' sshare of capacity to 1. 21 MGD. The cost estimate of interim improvement projects to MWQCF was estimated at a total $ 32. 8 million in the August 2022 letter and updated to $79. 6 million in Manteca' s2023 draft Wastewater Master Plan ( Manteca, 2022; 2023).

The draft Manteca Wastewater Master Plan additionally evaluated a Phase IV Expansion Project that would further increase MWQCF' scapacity from 8. 23 MGD to 17. 5 MGD to serve projected population growth in its service area. The recommended Phase IV Expansion Project includes two 4. 65 MGD stages, with the cost of Stage 1 estimated at $ 146. 3 million and Stage 2 at $ 70. 6 million.

The City is currently assessing its rights to capacity at the MWQCF and the appropriate level of contribution to improvements at the MWQCF to meet its current and buildout wastewater treatment needs. It is anticipated that the City will identify such improvements as a CIP once an agreement is established.

8. 1.2 Lathrop CTF Phase 3 Expansion
The current Phase 2 expansion Lathrop CTF has a hydraulic capacity of 2. 5 MGD at elevated wastewater strength levels. As discussed in Section 5. 1, wastewater ADWF to the Lathrop CTF is projected to soon exceed this capacity before 2025. The City has initiated Phase 3 expansion of the facility to a total ADWF capacity of 5. 0 MGD. As shown in Table 8-1, the total projected OPC for the Phase 3 expansion is approximately $ 23. 7 million based on the City' s FY 2023-4 CIP plan ( WW 22- 38).

The Phase 3 expansion is projected to meet flows from the new development areas through 2040, until when the City may need a fourth expansion of the facility. eki environment
water
8- 1
December 2024
EKI C20049. 02
377
Section 8 2024 WWSMP Amendment
Capital Improvement Program Changes to the 2019 WWSMP City of Lathrop

8. 2 Modification to Collection System CIPs
The hydraulic evaluation presented in Section 7 showed a reduction in hydraulic deficiency locations compared to those presented in the 2019 WWSMP as a result of CIPs completed since the 2019 WWSMP and lower wastewater flow projections. In particular, (1) the Woodfield Pump Station upgrade WW 22- 26) was completed in 2019; and ( 2) the Crossroads gravity main replacement project ( WW 22- 27) is no longer necessary. As such, these projects are removed or modified from the list of recommended CIPs.

The Stonebridge LS is approximately 40- gpm over capacity and the North Harlan PS has significant excess capacity. As an alternative to Project WW -1, North Harlan Rd businesses which currently pump into the Stonebridge collection system could instead tie -into North Harlan Rd SSFM.

The remaining collection system CIPs from the 2019 WWSMP have been reviewed and have been retained to address the potential deficiencies identified in the hydraulic assessment. However, EKI recommends additional analysis be conducted to confirm the required project extents and sizing. ek, environment
water
8- 2
December 2024
EKI C20049. 02
378
Section 8
Capital Improvement Program Changes to the 2019 WWSMP
2024 WWSMP Amendment
City of Lathrop
Table 8-1. Summary of Capital Improvement Projects
Addresses
Project Modeled
Project Timeframe
Number Surcharging in
Existing Scenario
Treatment Facility Improvement Projects
Total Project OPC ( a)
WWT- 1 Manteca Interim Improvements Near -term (b)
WWT 2
CTF Phase 3 Expansion ( WW 22 -
Near
3WW-1-
term (c) 23, 700, 000
CTF Surface Water Discharge ( WW
20- 17) (d) Existing 12, 699, 000
Total Treatment Facility Improvements OPC 36,99, 000
Collection System Improvement Projects
WW -1
Stonebridge Gravity Main
Replacement and Pump Station
Upgrade ( WW 22-5) (e)
Existing No 850, 00
WW 2A
Woodfield West Deficiency Project
Alternative A (WW 22 26)
Existing (f) No 2, 730, 000
WW 26
Woodfield West Deficiency Project
Alternative B ( WW 22 26) Existing ( f) No 2, 400, 000
WW 4
J Street Gravity Main Replacement
Project
Existing ( f) Yes 1, 690, 00
WW -5
Easy Court / O Street Gravity Main
Replacement Project
Existing No 1, 370, 000
WW -6 O Street Pump Station Upgrade Existing No 1, 560, 000 Total Collection System Improvements OPC 10, 500, 000
Miscellaneous Collection System Projects
WW -8 Temporary Flow Monitoring 100, 00
WW 9
Wastewater Lift Station Access
Modifications ( PW 24- 14) (d)
FY 23-5 CIP 475, 000
WW 9
Ozone Upgrade for Wastewater
Pump Stations ( PW- 24- 15) (d)
FY 23-5 CIP 75, 000
Total Miscellaneous Collection System Improvements OPC 650, 00 Notes:
a) Costs shown are presented in December 2024 dollars based on an ENR CCI of 13, 632. 41 (20 -city average).
b) City is currently evaluating the appropriate level of contribution to improvements at the MWQCF. c) City is currently issuing a request for proposal to PACE which may update this project OPC. d) Project included as a part of the City of Lathrop Capital Improvement Programs Fiscal Years 2023-025 report.
e) Connecting North Harlan Rd businesses which currently pump into the Stonebridge collection system to the North Harlan Rd SSFM can be considered as an alternative. f) Project addresses existing deficiencies, however future development influences recommended pipe or pump sizes to be installed.
ek, environment
water
8-3
December 2024
EKI C20049. 02
379
r
WW -4: J Street
Gravity Main
Replacement
t_L LJ
WW -2B: Woodfield West
Deficiency Project
Alternative B

DE LIMA RD

DOS REIS R
WW -1: Stonebridge Gravity Main
Replacement and Pantie'
i Force Main
t/W- 6: O Street
PS Replacement w
1 WW -5: EasyCourUO Street\
Gravity Main Replacement
Lathr
CTF
WW -2A: Woodfield West
Deficiency Project - Alternative A

LATHROP RD
1I
1 1 LOUISE AV
1 a
ti
I—I ,
s. . tVOSEMITE AV
lit MWQj
Ll, e
end
7I. Sphere of Influence
Approximate Area of W WTF
E7a Pump Station or Lift Station
MI Pump Station or Lift Station Upgrade
Force Main
Gravity Main
Diameter of Replacement Sewer
10"
12"
15"
t
18"
Diameter of New Force Main
Abbreviations
CTF = Consolidated Treatment Facility
MWQCF = Manteca Water Quality Control Facility
WWTF = wastewater treatment facility
Notes

1. All locations are approximate.

2. A detailed map for each project is included in Appendix D Sources

1. Aerial photograph provided by ESRI' s ArcGIS Online, 12 March 2024.

N 0
A
2, 500 5, 000
SP. in Fecal
Recommended Collection System
Improvement Projects
Wastewater System Master Plan Amendment
City of Lathrop
Lathrop. CA
environment
December 2024 Cthrop, 2
water Figure & 1
380
Section 9
References
2024 WWSMP Amendment
City of Lathrop
9 REFERENCES
California DOF, 2007. E- 4 Revised Historical City, County and State Population Estimates, 1991- 2000, with 1990 and 2000 Census Counts, August 2007.

California DOF, 2012. E- 4 Population Estimates for Cities, Counties, and the State, 2001-10, with 2000 2010 Census Counts, November 2012.

California DOF, 2022. E- 4 Population Estimates for Cities, Counties, and the State, 2011-020, with 2010 Census Benchmark, May 2022.

California DOF, 2023. E- 5 Population and Housing Estimates for Cities, Counties, and the State, January 2021-023, with 2020 Benchmark, May 2023.

EKI, 2019a. Wastewater System Master Plan, City of Lathrop Integrated Water Resources Master Plan Update, final December 2019.

EKI, 2019b. Water System Master Plan, City of Lathrop Integrated Water Resources Master Plan Update, final December 2019.

EKI, 2019c. Recycled Water System Master Plan, City of Lathrop Integrated Water Resources Master Plan Update, final December 2019.

EKI, 2024. Recycled Water System Master Plan Amendment, City of Lathrop Integrated Water Resources Master Plan, draft November 2024.

Stantec and Herwit, 2022. City of Manteca WQCF 2021 Capacity Assessment, prepared for the City of Manteca, dated 18 March 2022.

Lathrop, 2022a. City of Lathrop General Plan, August 2022. Available at: https:// lathrop. generalplan. org/ Lathrop, 2022b. River Islands Phase 2 Project, https:// www. ci. lathrop. ca. us/ planning/ page/ river- islandsphase- 2- project Lathrop, 2022c. City of Lathrop Department of Public Works Design & Construction Standards. Available at: https:// www. ci. Iathrop. ca. us/ publicworks/ page/ design- construction- standards Lathrop, 2023. Capital Improvement Programs Fiscal Years 2023-025. Available at:
htt ps:// www. ci. lath rop. ca. us/ finance/ page/ budget Lathrop County Water District and the City of Manteca, 2002. Amendment to Agreement dated March 5, 1984 between Lathrop County Water District and the City of Manteca Concerning Waste Water Treatment.

Manteca, 2022. City of Manteca — Wastewater Quality Control Facility Capacity, letter dated 30 August, 2022.

Stantec, 2023. City of Manteca Wastewater Master Plan, prepared for the City of Manteca, Final Draft dated November 2023.

PACE, 2021. Technical Memorandum: City of Lathrop CTF Phase 3 Expansion Discussion, dated 15 September 2021.

SWRCB, 2016. Order WQ- 2016- 008- DDWWater Reclamation Requirements for Recycled Water Use, 7 June 2016.
eki environment
water
9-1
December 2024
EKI C20049. 02
381
Section 9
References
2024 WWSMP Amendment
City of Lathrop
RWQCB, 2016. Order R5- 2016- 0028-1 Waste 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, 21 April 2016.

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 County, California Regional Water Quality Control Board Central Valley Region, 14 March 2022.
eki environment
water
9-2
December 2024
EKI C20049. 02
382
Appendix A
WASTEWATER GENERATION FACTOR EVALUATION eki

APPENDIX A

WASTEWATER GENERATION FACTOR EVALUATION
environment
water
383
Appendix A

WASTEWATER GENERATION FACTOR EVALUATION
A. WASTEWATER GENERATION FACTOR EVALUATION
eki environment
water
The following section describes the analysis performed to verify and update land -use specific wastewater generation factors developed by EKI in the City' s 2019 Integrated Water Resources Master Plan ( IWRMP).

As the City meters wastewater flows only at pump stations or at treatment plants, it is difficult to determine existing wastewater flow rates by individual land uses or sectors. However, wastewater use by individual sector can be estimated using historical water billing data. The analysis herein estimates wastewater flow rates using historical minimum month water use data and its ratio compared with measured average dry weather flow (ADWF).

EKI first evaluated the City' s water billing data for each applicable land use category and calculated the unit volume of minimum month water use for an individual dwelling unit ( gpd/ du) or each acre of commercial, industrial, and institutional ( CII) development ( gpd/ acre). This factor was then multiplied by either the uniform City- wide or development -area - specific ratios between water use and the ADWF ( see Section A. 1) to estimate the unit volume of wastewater ADWF, or gallons of wastewater per day per dwelling unit or acre ( gpd/ du and gpd/ acre, respectively). These unit flow factors represent estimated ADWF measured downstream at the wastewater treatment plants, which includes base sanitary flow (BSF) and year- round groundwater infiltration into the collection system.

The updated wastewater flow factors are listed in Table A- 4. As discussed below, a separate set of factors for River Islands low and medium density residential land uses has been developed to account for the unique residential per unit water use and existing lower I&due to the age of the collection system in this development area. A safety factor of 15% has been applied to the unit wastewater flow for the River Islands factors to account for the expected increase in I&in the future as the sewer system ages. A lower safety factor of 10% has been applied to the City- wide per unit wastewater generation factors to account for the relatively new developments and their local wastewater collection systems in Mossdale and Central Lathrop Specific Plan ( CLSP) development areas.

The process used to develop updated wastewater factors for each land use category is described in the following sections.

A. 1 Wastewater Flow and Water Use Comparison
To evaluate the relationship between water use and wastewater generation, EKI compared monthly water use derived from the City' s account - level water billing data to wastewater generation within each drainage area. By comparing water use to wastewater flows during the winter months, when little water is typically used outdoors, one can assess the amount of I&. For example, without significant I&, wastewater flows are typically only slightly lower than water use in winter, assuming the majority of indoor water use drains to the wastewater collection system. Wastewater flows in excess of water use during the winter would be indicative of contributions from I&.

Monthly average wastewater flow and water use from non -irrigation accounts between January 2017 and December 2021 for each collection system are shown on Figure A- 1. Wastewater flows in the MWQCF Manteca Water Quality Control Facility) drainage area was based on the SCADA at the MWQCF site, while the LCTF ( Lathrop Consolidatedh Treatment Facility) no River Islands drainage area wastewater flows was calculated by subtracting the River Islands pump station SCADA from the SCADA data at the LCTF site, City of Lathrop A- 1
Wastewater System Master Plan Amendment
December 2024
EKI C20049. 02
384
Appendix A
WASTEWATER GENERATION FACTOR EVALUATION e
environment
1 & water
which treats wastewater from Mossdale, River Islands, CLSP, South Lathrop, and Lathrop Gateway development areas as shown in the system schematic shown in Section 3. 1, 2 While water use generally exhibits strong seasonal trends largely due to landscape irrigation, wastewater generation appears similar from month to month. During the winter months, overall wastewater flows in the MWQCF drainage area ( i.e., Historic Lathrop Infill areas) and LCTF drainage area ( i.e., the rest development areas within the City) without River Islands are nearly equivalent to water use. Specifically, in the River Islands development area, wastewater flows are approximately 80% of winter water use. 3 Table A- 1
compares ADWF to water use during the month with the least water use ( Le. "minimum month water use") for each winter from 2017 to 2022 to assess the amount of infiltration. Wastewater flows range from 84% to approximately 115% of minimum month water use in the MWQCF drainage area. In LCTF drainage area, the 5 -year average ADWF is 95% of minimum month water use, while in River Islands, the ADWF is approximately 84% of minimum month water use. Without River Islands' wastewater flow contributions, the LCTF ADWF to water use increased to as high as 110%. It may be indicative of I&from the rest LCTF development areas draining to the LCTF collection system. 4 Citywide, the ADWF to water use ratio during minimum water use months is about 98% during the five- year window.

The May 2019 wastewater flow spike at the MWQCF station resulted from an abnormal meter reading, impacting the City- wide data, which is the sum of LCTF and MWQCF flows. 2 May 2018 and July 2019 wastewater flow SCADA data in the LCTF drainage area and River Islands were excluded due to negative readings at the River Islands pump station. The spike observed in June 2021 was considered an irregular meter reading compared to the historical flow pattern at the station. All reading errors at this station were not reflected in the LCTF flow data.
3 A 80% ratio between wastewater flows and winter water use is lower than typically expected and may indicate that there is significant winter -time landscape irrigation in River Islands. One potential reason may be because these newer homes are equipped with irrigation timers that residents forget to reset in the winter. 4 Significant I&had been identified in Crossroads in the previous Wastewater System Mater Plan ( EKI, 2019), however, Crossroads Pump Station SCADA data was not available during this preparation of this update.

City of Lathrop A- 2
Wastewater System Master Plan Amendment
December 2024
EKI C20049. 02
385
Appendix A

WASTEWATER GENERATION FACTOR EVALUATION
0 a
on
a)
m
Ia)
0 C
0 2, 500, 000
2, 000,00
1, 500, 00
1, 000,00
500, 00
eki environment
water
Figure A- 1 Monthly Water Use and Wastewater Flow by Collection System A. LCTF
0 Jan - 17 Aug -17 Feb -18 Sep -18 Mar -19 Oct -19 Apr -20 Nov -20 Jun - 21 Dec -21 Month
1— Water Use -— WW Flow - SCADA
B. MWQCF
3, 000,00
2, 500, 000
2, 000,00
1, 500, 000
1, 000,00
500, 00
0 Jan - 17 Aug -17 Feb -18 Sep -18 Mar - 19 Oct -19 Apr -20 Nov -20 Jun - 21 Dec -21 Month
41-- Water Use — I-- WW Flow - SCADA
City of Lathrop A- 3
Wastewater System Master Plan Amendment
December 2024
EKI C20049. 02
386
Appendix A

WASTEWATER GENERATION FACTOR EVALUATION
Monthly
Average (
gpd)
1, 200, 00
1, 000,00
800, 00
600, 00
400, 00
200, 00
eki
Figure A- 1 (Continued)
Monthly Water Use and Wastewater Flow by Collection System C. Mossdale
environment
water
0 Jan - 17 Aug -17 Feb - 18 Sep -18 Mar -19 Oct -19 Apr -20 Nov - 20 Jun - 21 Dec -21 Month
tWater Use — 4— WW Flow - SCADA
D. City -Wide
5, 000,00
4, 500, 000
4, 000,0
a
0-
3, 500, 000
0o
m 3, 000,00
m
2, 500, 000
Q
2, 000,00
c
0 1, 500, 000
1, 000,00
500, 00
0 Jan - 17 Aug -17 Feb -18 Sep -18 Mar -19 Oct -19 Apr -20 Nov -20 Jun - 21 Dec - 21 Month
4--- Water Use - AI-- WW Flow - SCADA
City of Lathrop A- 4
Wastewater System Master Plan Amendment
December 2024
EKI C20049. 02
387
Appendix A
WASTEWATER GENERATION FACTOR EVALUATION e
environment
8( water
Table A- 1 Minimum Month Water Use and ADWF
ADWF as a Percentage
MWQCF ( b) LCTF ( c)
of Minimum Month Water Use (%) ( a)
LCTF ( no RI) River Islands City -Wide
2017 99% 97% 94% 112% 98%
2018 110% 90% 96% 68% 101%
2019 115% 104% 110% 86% 110%
2020 98% 87% 91% 80% 93%
2021 84% 96% 108% 76% 90%
2022 73% 89% 85% 77% 80%
Average 101% 95% 100% 84% 98%
Notes:
a) Calculated as the ADWF of a given year divided by the water use during the minimum water use month of the previous winter. Dedicated irrigation accounts are excluded from this evaluation. b) Because it is difficult to discern the portion of wastewater that is managed onsite or discharged to the city' s wastewater system, historical water use in the McKinley drainage area is assumed to be equal to wastewater generation in this evaluation. c) Including River Islands, Mossdale, CLSP, South Lathrop, and Lathrop Gateway development areas.

A. 2 Residential Wastewater Flow Factors
Similar to the residential water use evaluation presented in the IWRMP Water System Master Plan Amendment ( EKI, 2024), various development - area -specific zoning classes were simplified into one of three categories: Low Density Residential ( LDR), Medium Density Residential ( MDR), and High Density Residential ( HDR). LDR accounts for Single -Family accounts with lot sizes larger than 4, 000 square feet, while MDR includes Multi -Family accounts and Single - Family accounts with lot sizes equal to or less than 4, 000 square feet. 5 HDR exclusively represents apartment land use. According to the San Joaquin County Assessor data and the account type from the billing records, the residential classes were assigned to each residential land use category are shown on Figure A- 2.

After grouping the residential parcels, minimum month water use in each year between 2017 and 2021 was evaluated on a parcel -by -parcel basis and multiplied by the ADWF ratios ( Table A-1) to develop residential wastewater flow factors for each existing residential land use category.

The HDR wastewater flow factor was exclusively derived from the water usage of the Towne Centre Apartments from November 2022 to June 2023 due to limited prior occupancy rates and billing data availability. Therefore, HDR flow factor was evaluated separately.

Account type extracted from the City' s potable water billing data. Lot size information based on San Joaquin County Assessor data.

City of Lathrop A- 5
Wastewater System Master Plan Amendment
December 2024
EKI C20049. 02
388
VINSC
OS MI
1 Legend
Sphere of Influence
Development Areas
Central Lathrop
Qf -1Crossroads
LJ Historic Lathrop Ingll and Other Developments
C3 Lathrop Gateway
Mossdale Landing
Mossdale Landing East
Mossdale Landing West
Mossdale Landing South
ORiver Islands
Sharpe Army Depot
South Lathrop
Land Use Categories
Low Density Residential
Medium Density Residential
High Density Residential
Notes

1. All locations are approximate.

2. Includes all residential accounts with at least one full year of billing data.

Sources

1. Aerial photograph provided by ESRI' s ArcGIS Online. 7 March 2024.

N o O00 8. 000
A Isv. nr_, l
Residential Land Use Categories
Water System Master Plan Amendment
City of Lathrop
Lefton. CA
environment
December 2024
C200490t
water Figure A- 1
389
Appendix A
WASTEWATER GENERATION FACTOR EVALUATION eki environment water
As shown in Table A- 3, the available data were then evaluated to assess the extent to which each collection system had unique wastewater generation patterns. Figure A- 3 and Figure A- 4 show the results of this evaluation for LDR and MDR units, respectively. The data show that estimated unit wastewater generation in River Islands was approximately 20% lower than the minimum month water use per unit, and average water usage per unit at these homes was generally lower than City- wide average water use per unit. It may be caused by significant winter -time landscape irrigation in this development area ( see footnote 3 above). For the rest of the City, the estimated residential wastewater generation was generally equal to or slightly higher than the estimated minimum month water use per unit. This is likely due to the aging of the wastewater collection system within older historic Lathrop collection system which makes it more subject to I&compared to the newer West Lathrop collection system.

The ADWF in the MWQCF drainage area ( i.e., Historic Lathrop) and LCTF drainage area ( excluding River Islands) observed during 2017-021 are similar to the observed Historic Lathrop average flow during the 2018 flow monitoring period, while ADWF in River Islands is slightly lower than the observed West Lathrop flow. Additionally, the 2018 flow monitoring results provided further evidence that unit wastewater generation is different between the two portions of the City.

Based on the analysis and flow monitoring results described above, separate LDR and MDR wastewater flow factors were developed for the River Islands and the remaining City- wide units. There were no HDR i.e., apartments) in River Islands as of the preparation of this evaluation. Therefore, a uniform high density flow factor was assumed. Due to the newer age of the sewer system in River Islands, a 15% safety factor is applied to units in this development area to account for the expected increase in infiltration in the future as the sewer system ages. Therefore, a wastewater flow factor of 200 gpd/ du was selected for the River Islands LDR units based on calculated maximum wastewater generation per unit between 2017 and 2021 and the 15% safety factor. A safety factor of 10% was applied to the City- wide wastewater flow factors, assuming sewer conditions and infiltration will not be significantly worsened in the Historic Lathrop area and the collection system will gradually age in the remaining LCTF drainage area. As such, a wastewater flow factor of 240 gpd/ du was selected for City- wide LDR units, which is consistent with the previously developed Historic Lathrop LDR wastewater flow factor.

Similarly, wastewater flow factors of 200 gpd/ du and 155 gpd/ du were selected for City- wide and River Islands MDR units, respectively. A wastewater flow factor of 170 gpd/ du was selected for HDR units. The HDR flow factor is assumed to apply to all apartment units within the City.

City of Lathrop A- 7
Wastewater System Master Plan Amendment
December 2024
EKI C20049. 02
390
Appendix A
Wastewater Generation Factor Evaluation
Table A- 2
Residential Wastewater Flow Factor Evaluation
Year MWQCF ( Historic Lathrop) LCTF ( West Lathrop, no RI) Estimated
Unit ADWF
d)
bpd/ du)
River Islands
Unit Water
Use h)
gpd/ du)
Citywide
Minimum
Month Water
Use ( a)
gpd)
Number of
Active
Accounts
a)
Unit Water
Use( b)
gpd/ du)
ADWF vs.

Water Use
Ratio ( c)
Estimated
Unit ADWF
d)
Igpd/ du)
Minimum
Month Water
Use ( a)
gpd)
Number of
Active
Accounts
a)
Unit Water
Use (b)
gpd/ du)
ADWF vs.

Water Use
Ratio ( c)
Minimum
Month Water
Use ( a)
gpd)
Number of
Active
Accounts
a)
ADWF vs.

Water Use
Ratio (c(
Estimated
Unit ADWF
d)
gpd/ du)
Estimated
Unit ADWF
e)
gpd/ du)

MEEKIMIIIIIIIIEEMIIIIIII
IIESZE IIIIIEIMllllllIMINllllEEMllllll" _
IIIIEZEIMIIIIIIIEIMIEMUINIMIEZM®= EIMMILEM
1482 MIMllllllll® IIIIE
MIIZMINEMMEMIIMEM® NEZEINI®®''
111111® lllKII= lllllllll' lf MDIMMECEUIZEIIMISUSIMII
ll®IlllllIEMIN®®
llllllllI£!®®

IMEEINI
2018 p
2019 r®'"" IMEM®' 1, 347
lull MECOM ENI® 1, 455 211, 000
MI= III®'
rg&/ um Density
ECIIIIIMMEEMMENIIIIIIMIIIIIIMMIMMIEINIIMI= MMMEMIIIIIISIMM2MMIIIIIIMILMIl lIllIEESIMMIIMMEM

IIMIIIIIIIMIIII IIIEEMIIIIIIIEIMINMEMIIIIIII IIIIIIIE
IIIIIIIIIIIIIIIIIIIIIMMINIIIIIIIIIMIIIIIIIIIIIIIIIIIIIr IIIIEMEE IIIIMEM®
llllllllMI®®'

1. 000 IIIIIIIIIIIIIIIIIIMIIIIIIIIyElE
lllllll
IllllECEMIIIIIEMllllllll= 111111113
U
llllllll
46- 003
llEZEIMI® MEMIN
0MIMIIMEZMIMEIMM® M

UECMMEEMIEMMEMINIEMIMEWII
ESEEM llEIIN®
IllllliEMI® 0'
Notes
a) Water use data are obtained from the City' s billing system. b) Unit water use equals the minimum month water use divided by the number of active accounts. c) The ADWF to Water Use Ratio for each drainage area is obtained from Table A- 2. 4) Estimated ADWF is calculated by muhiplying the Unit Water Use by the ADWF to Water Use Ratio. e) Citywide Estimated Unit ADWF is calculated using the citywide estimated ADWF in gallons per day, divided by the city' stotal number of active accounts. eki A- 8 December 2024
EKI C20049. 02
391
Appendix A

WASTEWATER GENERATION FACTOR EVALUATION
Y

4. 250
200
o
LL` 150
v
a
m
ai 100
aa) 50
L
ai
f0 0
eki environmentwater
Figure A- 3 Low Density Residential Wastewater Flow Factor Evaluation 300
176
228
209
205
218
2017 2018 2019 2020 2021
Year
Water Use - MWQCF
Water Use- River Islands
Wastewater Flow- LCTF
Citywide Wastewater Flow
Water Use - LCTF
Wastewater Flow- MWQCF
Wastewater Flow - River Islands
300
250
200
150
100
50 Figure A- 4 Medium Density Residential Wastewater Flow Factor Evaluation 300
00 250
w
411
200
3 150
v
a
3 "
N 100
50 w
0 156
189
177
157
184
2017 2018 2019 2020 2021
Year
Water Use - MWQCF
Water Use - River Islands
Wastewater Flow - LCTF
Citywide Wastewater Flow
Water Use - LCTF
Wastewater Flow - MWQCF
Wastewater Flow - River Islands
300
250
200
150
100
50 City of Lathrop A- 9
Wastewater System Master Plan Amendment
December 2024
EKI C20049. 02
392
Appendix A
WASTEWATER GENERATION FACTOR EVALUATION e
environment
water
A. 3 CII Wastewater Flow Factors
Per acre wastewater flow factors were developed for commercial, industrial, parks, and schools/ institutional land uses based on minimum month water use and ADWF between 2017 and 2021.

For each CII land use, minimum month water use for each year between 2017 and 2021 was divided by the total land use acreage of active accounts, then multiplied by the ADWF ratio, to determine wastewater flow factors. Acreages were calculated by cross- referencing the City' s billing database with the San Joaquin County parcel database.

As discussed in the City' s
Water System Master Plan Amendment, City staff identified certain CII users need reclassification in regard to the account type from the billing data, which significantly altered the results compared to the CII wastewater generation factors developed in the City' s 2019 IWRMP. Figure A- 5 shows which individual parcels fell into each land use category, as confirmed by City staff.

General commercial and industrial water use factors were updated based on commercial and industrial minimum month water use, respectively. Table A- 3 shows an evaluation of commercial and industrial estimated water flow between 2017 and 2021. Estimated wastewater flows are compared between each collection system, as the MWQCF system represents the Historic Lathrop area, the LCTF drainage area represents new developments in West Lathrop. 6
Estimated commercial wastewater flow varies
significantly across the systems, ranging from less than 300 gpd/ acre in the LCTF area to more than 900 gpd/ acre in the MWQCF area.' This is likely due to highly variable water use between the types of commercial businesses across the City. The evaluations of commercial and industrial wastewater flows are illustrated on Figure A- 6 and Figure A- 7, respectively.

As parcel -level commercial and industrial wastewater flow is largely determined by the specific type of business, uniform or " Citywide" factors were developed to project future commercial and industrial wastewater generation, assuming that the existing profile of business and industries within the City will continue into the future. The wastewater flow factors were determined to be 755 gpd/ acre for Commercial land uses and 240 gpd/ acre for Industrial land uses including a 10% safety factor to account for the average future increase in infiltration in old and new sewers City- wide. Compared to the 2019 IWRMP, the commercial wastewater flow factor increased by approximately 28% from 590 gpd/ acre, which is likely due to a significant portion of commercial accounts were corrected as industrial, government, or park land uses.

The industrial wastewater flow factor decreased by approximately 28% from 335 gpd/ acre, which may be partially attributed to the improved I&conditions within the Crossroads development area. As shown in Table A- 1, the 5 -year average ADWF to Minimum Month Water Use ratio in the LCTF drainage area, where the Crossroads located within, is 95%, approximately 32% lower than the prior Crossroads 5 -year average ratio of 140%.

Since no industrial units currently exists or has been planned in River Islands, no separation of River Islands and the rest of LCTF was performed for CII wastewater flow factor evaluation.

Water use in during the minimum water use month in the Crossroads area in 2014 is likely to be an anomaly.

City of Lathrop A- 10
Wastewater System Master Plan Amendment
December 2024
EKI C20049. 02
393
Legend
Sphere of Influence
Development Areas
L _ __- 1 Central Lathrop
OCrossroads
O Historic Lathrop Inflll and Other Developments
QLathrop Gateway
Q Mossdale Landing
Mossdale Landing East
Mossdale Landing West
Mossdale Landing South
O River Islands
Sharpe Army Depot
CD South Lathrop
Land Use Categories
Commercial
Inn Industrial
an Park
School
MI Government
Notes

1. All locations are approximate.

2. Includes all residential accounts with at least one full year of billing data.

Sources

1. Aerial photograph provided by ESRI' s ArcGIS Online, 6 March 2024.

N o 4, 000 8, 000
ISw4 n Fri)
CII Land Use Categories
Water System Master Plan Amendment
City or Lathrop
Lathrop, CA
environment
December 2024
C2004a O1
water Figure A- 5
394
Appendix A
Wastewater Generation Factor Evaluation
Table A- 3
Commercial and Industrial Wastewater Generation Factor Evaluation Year MWQCF ( Historic Lathrop) LCTF ( West Lathrop) Citywide Minimum
Month Water
Use
gpd)
Land Use of
Active
Accounts
acres)
Unit Water
Use
gpd/ ac)
ADWF vs.

Water Use
Ratio
Estimated
Unit ADWF
gpd/ ac)
Minimum
Month Water
Use
gpd)
Land Use of
Active
Accounts
acres)
Unit Water
Use
gpd/ ac)
ADWF vs.

Water Use
Ratio
Estimated
Unit ADWF
gpd/ ac)
Estimated
Unit ADWF
gpd/ ac)
minec, c
2017 62,13 68 919 99% 906 18, 806 50 374 97% 361 675
2018 77, 839 71 1096 110% 1204 20, 065 80 251 90% 227 686 2019 63, 903 74 864 115% 990 25, 774 84 306 104% 318 633 2020 70,10 82 862 98% 843 20, 000 55 365 87% 320 634
2021 82, 323 97 853 84% 715 17, 419 51 340 96% 325 580
2017 85, 097 449 189 99% 187 85, 548 427 200 97% 194 190 2018 105, 097 436 241 110% 264 79, 452 436 182 90% 165 215 2019 57, 290 447 128 115% 147 73, 129 409 179 104% 186 165 2020 96, 419 516 187 98% 183 56, 419 381 148 87% 130 160 2021 63, 935 501 128 84% 107 70, 194 371 189 96% 181 139 Notes:
a) Water use data are obtained from the City' sbilling system. b) The ADWF to Water Use Ratio for each drainage area is obtained from Table A- 2. c) Estimated ADWF is calculated by multiplying the Unit Water Use by the ADWF to Water Use Ratio. d) Citywide Estimated Unit ADWF is calculated using the citywide estimated ADWF in gallons per day, divided by the city total number land use in acres. eki1 & water
A- 12 December 2024
EKI C20049. 02
395
Appendix A

WASTEWATER GENERATION FACTOR EVALUATION
u
1200
a
ao
1000
800
o0
rz 600
w
v 400
V)
200
Q1 0 1-+
300
250
200
150
100
50 0
e
environment
water
Figure A- 6 Commercial Wastewater Flow Factor Evaluation 2017 2018 2019 2020 2021
Year
Water Use - MWQCF Water Use - LCTF
Wastewater How - MWQCF= Wastewater Flow - LCTF
Citywide Wastewater Flow
Figure A- 7 Industrial Wastewater Flow Factor Evaluation 2017 2018 2019 2020 2021
Water Use - MWQCF
Wastewater Flow - MWQCF
Citywide Wastewater Flow
Year
Water Use - LCTF
Wastewater Flow - LCTF
1200
1000
800
600
400
200
300
250
200
150
100
50 0
City of Lathrop
Wastewater System Master Plan Amendment
A- 13 December 2024
EKI C20049. 02
396
Appendix A
WASTEWATER GENERATION FACTOR EVALUATION e
environment
1 & water
The wastewater flow factor for parks was quantified based on minimum month water use data for the following parks with indoor ( i.e., restroom) water use:

Apolinar Sangalang, • Milestone Park,
Crescent Park, • Mossdale Landing Community Park,
Greens Park, • Park West,
Islanders Field, • William S. Moss Park,
Lathrop Generations Fitness Park, • Woodfield Park, and Manuel Valverde Park, • River Island Fields.

Michael Vega Park,
The wastewater flow factor for parks was determined to be 55 gpd/ ac including a City- wide 10% safety factor, which is consistent with the 2019 park wastewater flow factor.

School water use varies seasonally depending on the school calendar ( i.e., the highest water use months) were reviewed to evaluate wastewater flow. Water use data were reviewed for the Lathrop High School, one. Lathrop, NextGeneration STEAM Academy, River Islands Technology Academy, and the Lathrop Elementary School."
Minimum month water use data for several institutional uses ( i.e., fire stations, City HaII, post office) had been reviewed and determined to be similar to schools in the 2019 IWRMP, and there was no significant change observed in institutional water use since then. Therefore, wastewater generation for institutional uses and schools was combined into a single factor. Based on minimum month water use between 2017 and 2021 and the City- wide 10% safety factor, the wastewater flow factor for Schools/ Institutional was determined to be 220 gpd/ ac.

A. 4 Summary of Wastewater Flow Factors
Based on the information presented above, Table A- 4 summarizes the wastewater flow factors developed for the 2024 IWRMP Amendment.

Note that these wastewater flow factors are planning -level factors for evaluating infrastructure, while the City uses site -specific wastewater allocations to manage discharge and capacity fees. 8 Water use data from non -irrigation meters for schools such as the Mossdale Elementary School and the Joseph Widemer Jr. Elementary School showed significant seasonal patterns due to irrigation water use and were therefore excluded from this analysis.
9 Water use in 2020 from the NextGeneration STEAM Academy and River Islands Technology Academy were excluded from analysis due to irregular water billing data.

City of Lathrop A- 14
Wastewater System Master Plan Amendment
December 2024
EKI C20049. 02
397
Appendix A
WASTEWATER GENERATION FACTOR EVALUATION eki
Table A- 4 Updated Wastewater Flow Generation Factors
environment
water
Low Density Residential
Wastewater
City -Wide
240 gpd/ du
Flow Factor
River Islands
200 gpd/ du
Medium Density Residential 200 gpd/ du 155 gpd/ du
High Density Residential 110 gpd/ ac
Commercial 755 gpd/ ac
Industrial 240 gpd/ ac
Parks 55 gpd/ ac
Schools/ Institutional 220 gpd/ ac
City of Lathrop A- 15
Wastewater System Master Plan Amendment
December 2024
EKI C20049. 02
398
Appendix B
WASTEWATER PEAKING FACTOR EVALUATION eki environment
water

APPENDIX B

WASTEWATER PEAKING FACTOR EVALUATION
399
Appendix B 2024 WWSMP Amendment
Wastewater Peaking Factor Evaluation City of Lathrop
B. WASTEWATER PEAKING FACTOR EVALUATION
As part of the Wastewater System Master Plan ( WWSMP) Amendment, EKI updated the peaking factor curve that estimates peak wet weather flow (PWWF) using wastewater flow data collected between 2017 and 2022. PWWF is the highest hourly flow experienced during the year due to rainfall -induced I&and peak diurnal sanitary flows and is used to evaluate the hydraulic capacity of a wastewater collection system. PWWF peaking factors are typically higher in smaller drainage areas, in which there is little flow attenuation. Larger drainage areas provide a greater capacity to attenuate flows, as peak flows generated in the upstream reaches of the system take a longer
amount of time to travel downstream.

B. 1 Historical Peak Hourly Flow
The City provided discharge flow data and sump elevation data from several pump stations in 5 - minute increments between January 2017 and July 2022. Using these data, EKI calculated hourly inflow to each pump station by summing discharge and sump storage change.

EKI has observed occasional abnormal patterns in the SCADA flow data, possibly due to incorrectly registered flows in the SCADA system, or artificial flow peaks due to large scale construction and wastewater infrastructure maintenance. The data sets were processed in the programming language " R" in order to convert the 5 -minute SCADA data into useable hourly and daily averages. Additionally, manual processing was conducted in order to remove erroneous zero data and outliers. Summarized by pump station the following adjustments were made to the SCADA data:

Mossdale PS — Removed small portion of erroneous data from 2018 ( 124 data points) Stonebridge PS — Removed erroneous peak in 2021 ( 5 data points) Woodfield PS — Data from 1 January 2017 to 15 May 2021 was determined to be unreliable reliable due to incorrectly registered flows River Islands Main PS — November and December 2021 data was combined with the 2022 dataset
McKinley and O Street PS — Data was split into two sets for before and after 2 April 2021 for changes in pumping configuration.

To review data in detail, EKI calculated the Cumulative Distribution Function ( CDF) of peak hourly flow within each day, normalized by ADWF, for each pump station. The result of this analysis is shown together with CDFs calculated for the 2019 WWSMP on Figure B- 1. A typical CDF resembles a sigmoid function ( or " S -curve"), which can be observed during most years at each pump station. Several exceptionally high peak periods were observed at the Mossdale, Stonebridge, and O Street Pump Stations that were not found to be associated with rainfall. To eliminate anomalies in flow data, EKI selected the 99. 5 -percentile peak hourly flow as the PWWF during each year, as listed in Table B- 1.
ek, environment
water
B- 1 December 2024
EKI C20049. 02
400
Appendix B 2024 WWSMP Amendment
Wastewater Peaking Factor Evaluation City of Lathrop
B. 2 Peaking Factor Curve
Figure B- 2 plots historical PWWF versus ADWF for the City' s pump stations from 2013 through 2022 as well as peak hourly flow versus average flow for the 2018 flow monitoring locations by year and then by pump station. As shown on Figure B- 2, there is not an observed yearly trend of PWWF versus ADWF.

EKI fit a peaking factor curve based on these flow data, as shown on Figure B- 2, which EKI recommends be adopted for future evaluations to assess pumping and conveyance capacities. It can be observed that while other pump stations with long periods of records, such as Stonebridge, Mossdale, and McKinley, have data points scattered both above and below the estimate line, data from the O Street Pump Station concentrated below the estimated line. This indicates that peak flow observed at the 0 Street Pump Station are smaller than what is anticipated for pump stations at its size.

Given that the City' sdesign standard requires that 50% capacity be retained in most pipes1 under PWWF and that pump stations meet PWWF with their firm capacity, EKI believes that use of the calculated PWWF curve is appropriate. The design standard provides surplus capacity to accommodate flows from larger rain events to prevent capacity -related sanitary sewer overflows.
1 The City' s design standard requires 50% capacity to be retained in pipes with a diameter of 15 inches or smaller and 75% capacity to be retained in pipes with a diameter greater than 15 inches. ekienvironment water
B- 2
December 2024
EKI C20049. 02
401
Appendix B 2024 WWSMP Amendment
Wastewater Peaking Factor Evaluation City of Lathrop
Figure B- 1. Cumulative Distribution Functions of Historical Peak Hourly Flow Mossdale
Cumulative
Distribution
Frequency
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
i f • •
0 1 2 3 4 5 6
Peak Hourly Flow within Each Day / ADWF
2013 2014 • 2015 • 2016 • 2017 • 2018 • 2019 • 2020 • 2021 100%
90%
o80%
a,
U- 70%
c
60%
50%
v,
G 40%
30%
20%
10%
0% • _
0 Stonebridge
1 2 3 4
Peak Hourly Flow within Each Day / ADWF
5 2013 2014 2015 • 2016 • 2017 • 2018 • 2019 • 2020 • 2021 eki environment
water
B- 3
6 December 2024
EKI C20049. 02
402
Appendix B
Wastewater Peaking Factor Evaluation
2024 WWSMP Amendment
City of Lathrop
Cumulative
Distribution
Frequency
Cumulative
Distribution
Frequency
Figure B- 1. Cumulative Distribution Functions of Historical Peak Hourly Flow (Cont.) 100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
O St
0 0. 5 1 1. 5 2 2. 5
Peak Hourly Flow within Each Day / ADWF
2013 2014 • 2015 • 2016 • 2017 • 2018 • 2019 • 2020 • 2021 RI Main
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
3 0. 0. 5 1. 0 1. 5 2. 0 2. 5 3. 0 3. 5
Peak Hourly Flow within Each Day / ADWF
ek, environment
water
2021&022
B- 4
December 2024
EKI C20049. 02
403
Appendix B 2024 WWSMP Amendment
Wastewater Peaking Factor Evaluation City of Lathrop
Figure B- 1. Cumulative Distribution Functions of Historical Peak Hourly Flow ( Cont.) RI PS 2A
Cumulative
Distribution
Frequency
Cumulative
Distribution
Frequency
100% I .•....•• • rte• ..
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
100% - - • • • ,,.• • ••

0. 0. 5 1. 0 1. 5 2. 0 2. 5 3. 0 3. 5 4. 0
Peak Hourly Flow within Each Day / ADWF
2020 • 2021 • 2022
McKinley
90%
80%
70%
60%
50%
40%
30%
20%
10%
eki
0%

0. 0. 5 1. 0 1. 5 2. 0 2. 5 3. 0 3. 5 4. 0
Peak Hourly Flow within Each Day / ADWF
2020 Pre 4/ 2/021 • Post 4/ 2/021 • 2022
environment
water
B- 5

4. 5
December 2024
EKI C20049. 02
404
Appendix B 2024 WWSMP Amendment
Wastewater Peaking Factor Evaluation City of Lathrop
Figure B- 1. Cumulative Distribution Functions of Historical Peak Hourly Flow ( Cont.) Woodfield
Cumulative
Distribution
Frequency
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%

0.0 0. 50 1. 00 1. 50 2. 00 2. 50 3. 00 3. 50 4. 00 4. 50 Peak Hourly Flow within Each Day / ADWF
2021
eki environment
water
B- 6
December 2024
EKI C20049. 02
405
Appendix B
Wastewater Peaking Factor Evaluation
2024 WWSMP Amendment
City of Lathrop
Table B- 1. Historical Wastewater Flow and Peaking Factors ADWF PWWF Peaking Factor
Year
gpd) ( gpd) (a) ( b)
Mossdale Pump Station ( c)
2013 307, 410 830, 547 2. 70
2014 312, 268 732, 557 2. 35
2015 335, 693 1, 636, 267 4. 87
2016 408, 363 2, 008, 720 4. 92
Stonebridge Pump Station
2013 128, 478 367,26 2. 86
2014 121, 054 512, 057 4. 23
2015 116, 383 497, 90 4. 28
2016 120, 371 603, 360 5. 01
O St Pump Station
2013 675, 465 1, 406, 948 2. 08
2014 638, 801 1, 371, 470 2. 15
2015 612, 014 1, 393, 241 2.8
2016 622, 13 1, 310, 883 2. 11
MWQCF Flow Meter
2014 0 0 2. 02
Notes:
a) A 99. 5 -percentile daily peak flow was selected for the PWWF of each pump station to eliminate anomalies in the City' s
SCADA system data.
b) Peaking factor is calculated as the ratio of PWWF to ADWF. c) The City began weekly flushing of River Islands sewer system in 2015, which likely accounts for the significantly higher peak flows in 2015 and 2016. eki environment
water
B- 7
December 2024
EKI C20049. 02
406
Appendix B
Wastewater Peaking Factor Evaluation City of Lathrop
2024 WWSMP Amendment
Peak
Wet
Weather
Flow /
Average
Dry
Weather
Flow
6 5
4 3
2 1
0 eki
0 500, 00 1, 000,00 1, 500, 000
Figure B- 2. Historical Wastewater Flow and Peaking Factors Average Dry Weather Flow ( gpd)
IWRMP Peaking Factor
2014
2016
2017
2019
2021
2023 IWRMP Peaking Factor
environment
water
B- 8
2013
e 2015
2018 ( Flow Monitoring)
e 2018
2020
2022
2, 000,00
December 2024
EKI C20049. 02
407
Appendix B
Wastewater Peaking Factor Evaluation City of Lathrop
2024 WWSMP Amendment
Peak
Wet
Weather
Flow /
Average
Dry
Weather
Flow
6 5
4 3
2 1
0 0 500, 00 1, 000,00 1, 500, 000
Figure B- 2. Historical Wastewater Flow and Peaking Factors ( Cont.) Average Dry Weather Flow ( gpd)
2, 000,00
2016 IWRMP Peaking Factor • O Street
Mossdale e Stonebridge
Woodfield RI Main
McKinley 2023 IWRMP Peaking Factor
eki environment
water
B- 9
December 2024
EKI C20049. 02
408
Appendix C ekienvironment water

APPENDIX C
Summary of Monitoring Results from
Evaluation of Biochemical Oxygen Demand
Contribution to Manteca Water Quality
Control Facility
409
eki
DRAFT — 13 December 2023

MEMORANDUM
To:

From:

Subject:

Greg Gibson, P. E. (City of Lathrop)
Dave Umezaki, P. E. (EKI Environment & Water, Inc.)
Tina Wang, P. E., (EKI Environment & Water, Inc.)
environment
water
Summary of Monitoring Results from Evaluation of Biochemical Oxygen Demand Contributions to Manteca Water Quality Control Facility Wastewater System Master Plan Amendment Evaluation
City of Lathrop, California
EKI C20049. 02)
On behalf of the City of Lathrop ( City), EKI Environment & Water, Inc. has prepared this memorandum to summarizing the results of monitoring performed for evaluation of the City' s biochemical oxygen demand BOD), total suspended solids (TSS), and Total Kjeldahl Nitrogen (TKN) contributions to the Manteca Water Quality Control Facility ( MWQCF).

BACKGROUND AND MONITORING APPROACH
During October 2022, EKI performed monitoring to evaluate flows and BOD, TSS, and TKN concentrations at selected locations within the City' s wastewater collection system. The purpose of the monitoring was to provide additional data in response to correspondence from the City of Manteca indicating that the City of Lathrop was exceeding its allotted BOD loading limit from the Wastewater Capacity Agreement between the two cities.

Based on a review of the City of Lathrop wastewater collection system, EKI selected a total of five monitoring locations, generally shown on Figure 1 and in more detailed views on Figures 2 through 6.

These monitoring locations included the following:

A monitoring location at the North Harlan Pump Station wet well ( Figure 2) to capture the sewershed served by that pump station;
A monitoring location at the Stonebridge Lift Station wet well (Figure 3) to capture the sewershed served by that lift station;
A monitoring location at the Woodfield Lift Station wet well ( Figure 4), to capture the sewershed that is served by the North Harlan Pump Station, Stonebridge Lift Station, and Woodfield Lift Station;
A monitoring location at an O Street manhole located upstream of the Easy Court Lift Station Figure 5), to capture the sewershed that is served by that lift station; A monitoring location at the O Street Pump Station wet well ( Figure 6), to capture the sewershed that is served by the Valley Crossing Lift Station, J Street Pump Station, Easy Court Lift Station, and O Street Pump Station; and
410
Greg Gibson, P. E.

City of Lathrop
DRAFT — 13 December 2023

Page 2 of 3 ends

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
411
Greg Gibson, P. E.

City of Lathrop
DRAFT —13 December 2023

Page 3 of 3 ends

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
412
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
413
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
414
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
415
Road
Road
Sources

1. Aerial photograph provided by ESRI' s ArcGIS Online, 29 April 2021.

Noah
Hari: an PS
0 o'
1 1
1 I
1 1
I
12" PVC West i!
I
I
I
1 Legend
i"1 Sphere of Influence
Pump Station or Lift Station
MIN -- Force Main
Gravity Main
Notes

1. All locations are approximate.

N 0
A
300 600
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
416
C1SStA61-
1SS040-
1S$ 61 t‘15 _
1‘, 69) 1SS1
N1SSNACC$ 1S_ • moi
V. Wa1
N910
Apolinar
ts
Sangalang
1SS' 9
1SS a1 • Z0 9g' L
5 1SS 91
A
SSy11
Sy16
eqN. 9S y15
s5`''‘‘
PIM
tai
IE = - 5. 3 8" PVC East IN
IE = - 5. 15 8" PVC West IN
Joseph Widmer
1SS4, 9\\• 416, skok
OtooaiGarEeaccf
Stonebridge
is
A
1SS 90 • 9Io
1SSesN1
55O
933
Nk1
9oaaSS •
aS
1 aSS 33o OY: 5\
Boulders • • 6' S
y3y e'
s
SS\\yo
Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/ Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community
Legend
Pump Station or Lift Station
Force Main
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)
eki
Flow Monitoring Location -
Stonebridge PS
environment
water
City of Lathrop
Lathrop, CA
December 2022
EKI C20049. 02
Figure 3
417
0 2022\ 05 Fio3
9SSCt`
n
oxN9SS
13A 9SS 133
a
9SS 13L
o CeS
a1%
SS1g1 SSOI Ss19
u
9SS0° 1- o
a9 - ‘
3 09
C.
a 9Seskt` stN- SSy10
y y11-
S
y13
0 c3s5
21 9SS y11 VI , 9SS
a
9S
0 9SS kgy9
6pa 0\ 4
954' 0\ 95S y31
07 N1pSS 1pS
a
Woodfield
Lathrop
Ctles
0 cos
0' 3' 9SS0, 1
y
Augusta CO
9 9Sy11
c•
y9p y9ti , a9s\ yg1 , o95s •
jDmoCie ay
9Sa SSO
q
t r
Lathrop
1py1
D53
pSSteN1
Legend
Pump Station or Lift Station
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
418
Ei
Sources

1. Aerial photograph provided by ESRI' sArcGIS Online,
29 April 2021.
2\ 05\ Fiq5
OSt a
co
a, mN0L
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
5 419
05\ Fia5 s\2022\
OStl. mxd
Path:

X:\ C20049\ Ma

IN WO NW WIN
ss, tN39 N1S5*
NNE • • CONS N1
N\\ s‘tN3$ 6 N11ss 33
CkN
9 1SSN3 11SS. N3 NON
I sSON 9
N • N '
39a
N
1SN
N1SS3$ y Nag3
1ss
N
N'` 1s3 a N11s3. a
CONS
X10
N1S
3gy SAN
NO1s
a61
N1S
a66
N11S
N11SSNo\$ 1
N •11SON o\ 1saNse N • N11ss N' 5
Na9ti
S
N
Lathrop gOzEGIGTurEttccfl
aoa
Ns -
N •
1` sSOQ? ` ssN sS s`N
N • • • N y9 1
ssN6o 11ssoNaoti N
W' ® c st.

F.= 1. 91' 18" VCP North If , gy1
N1, S ' S
Na1y `' Na16
atom • 1L N
O
N1SSN y2 Gb
Otis ‘S• 4O -
N •
N'`" SS6a
a1 N1oN, yoss
Legend
Pump Station or Lift Station
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
420
G
a9
11 O
teal
Fig6 05\
McKinley. m
1 1
McKinley
a
B
119 19 \ 19 19b,
ON1 ,
j1 .

O1 • 1 011 115
PfCagg
O
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
421
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
422
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
423
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
424
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
425
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
426
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
427
Appendix D
Recommended CIP Details

APPENDIX D
Recommended CIP Details
eki environment
water
428
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
429
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
430
M
aps\ 2018\ 1 \
Delivers
x
8" PVC

RIF IN II IIIII II
i•8" PVC • • cp,, •• oo .°° 8".

I
I • .` a • • 8. rV
a,p = 8P:• • ii
L•:.
i;L
C , : • 8". VIP
4 •
gVCP ••
n: 8" VCR
8" PVC
c• •
I
I
I
I• 8" PVC • a a.

PVC f
IV
V•
Valley Crossings LS
CLIID
6" VCP• •
a
cos
6" VCP $ 6" VCP
U
05 Woodfield
LS
a 8" VCP
U
r`
c • • 8• VCP•
o i s 8' CP_
P • ••
PVC
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
431
M
ap
s\2018\
1 \
Delivers
o'
8"VCP•
8"AvCP
8„ VC P• •
8" VCP • 8" VCP• • • 8" VCP
6"VCP•
Valley
Crossings LS •
a_
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 • •
O 8" VCP 1 of
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
432
a
U
0 O
a
U
c2. 8"VCr
U
o•
8" VCP
8 •
9 •.• 8
VCP •...
a
6" VCP
3 8" PVC ' co'
CO.
o°
I)
n
8" PVC
Via'
C) o
U
6' VCP •• 8" VCP
6" VCP
Easy Ct LS
8" VCP
6" VCP
a
ib• 6" VCP •
G
C
I. 6" VCP • •
6 VCP
6" VCP
6" VCP
10" VCP
0 5>
co
t6" VIC P
VCP
0 U
8" VCP c°•
VCP•
6" VCP
41-
VCP• Nse
C)
OQ3
O St PS/
a
U
6" >
0 U
MIMI
P,
co • •
L
0 < - o
U
13 8" •VCP • n• •
CO >
8" VCP• .•
Legend
n
P
a
Delivers s\2018\ 1
X
C,
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
433

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
434
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
435
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
eki environment
water i
May 2025
EKI C20049. 03
436
2025 RWSMP Amendment
City of Lathrop

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
eki environment
water ii
May 2025
EKI C20049. 03
437
2025 RWSMP Amendment
City of Lathrop
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
eki environment
water iii
May 2025
EKI C20049. 03
438
2025 RWSMP Amendment
City of Lathrop

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
kienvironment water iv
May 2025
EKI C20049. 03
439
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
eki environment
water v
May 2025
EKI C20049. 03
440
2025 RWSMP Amendment
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.
eki environment
water ES - 1
May 2025
EKI C20049. 03
441
2025 RWSMP Amendment
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
May 2025
EKI C20049. 03
442
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.
ek, environment
water ES -3
May 2025
EKI C20049. 03
443
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 -
1 444
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
445
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:

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);
eki environment
water 1-
May 2025
EKI C20049. 03
446
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
eki environment
water 1- 2
May 2025
EKI C20049. 03
447
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' sSOI 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
water 2- 1
May 2025
EKI C20049. 03
448
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
water Figure 2- 1
449
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
ekienvironment water 2- 3
May 2025
EKI C20049. 03
450
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
water 2- 4
May 2025
EKI C20049. 03
451
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
water 2- 5
May 2025
EKI C20049. 03
452
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
453
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
454
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
455
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
456
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
457
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- 1 458
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
459
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
water 4-1
May 2025
EKI C20049. 03
460
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
eki environment
water 4- 2
May 2025
EKI C20049. 03
461
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
water 4-3
May 2025
EKI C20049. 03
462
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
water 4-
May 2025
EKI C20049. 03
463
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
water 4- 5
May 2025
EKI C20049. 03
464
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
465
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
eki environment
water 4-7
May 2025
EKI C20049. 03
466
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
water 5- 1
May 2025
EKI C20049. 03
467
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
water 5-2
May 2025
EKI C20049. 03
468
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
469
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
470
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
471
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.
kienvironment water 6- 3
May 2025
EKI C20049. 03
472
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
water 6- 4
May 2025
EKI C20049. 03
473
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
474
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
475
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
476
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
477
r
I
I
I
J
DE LIMP. PO
O

DOS REIS RD
O
jOO
O
O
a a
1, 0
00 8
I' O 1 -
u -
O.. I
O
O s
O
RI -PS Lx 1
O O
O
005EMi
O O O
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
478
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
479

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
480
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
481
DE LIMA.

O _,
s REIS RC
0 O ®>
0 O
O
r"._.... N. Imo'. ` r
O O
C.. ` O
E
O
o ® cc tOO
00 0 0
RI Phase PS It l s•—'‘. OO
0 O O
RI -PS Lx, 1
C PRV- 1
Upgraded
PMP\ 10
O
0 0
0 0
0 0 e
00 O
PRO - 2
Upgraded
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
482
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
483
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
484
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
485
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
486
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
487
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
488
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
489
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
490
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
491
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
492
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
493
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
494
2025 RWSMP Amendment
City of Lathrop

APPENDIX A
Water Balance Calculations
eki environment
water
495
fo
Assumpt
Flo
Requir
Efficien
Tree
App00
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

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
496
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
497

PAGE LEFT

INTENTIONALLY
BLANK
498
ITEM 4. 9

CITY MANAGER' S REPORT
OCTOBER 13, 2025 CITY COUNCIL REGULAR MEETING
ITEM: APPROVE PURCHASE OF NINE ( 9) FLEET VEHICLES
FROM MANTECA FORD -MERCURY, INC.

RECOMMENDATION: Adopt Resolution to Approve the Purchase of Nine 9) Fleet Vehicles from Manteca Ford -Mercury, Inc.

SUMMARY:

On September 16, 2025, staff released specifications for bid solicitations for the purchase of nine ( 9) fleet vehicles. The specifications for the purchase of fleet vehicles were formally advertised for bid on September 18, 2025, pursuant to California Public Contract Code ( PCC) 20160 and Lathrop Municipal Code ( LMC)

2. 36. 060. The City Clerk received and opened two ( 2) bids on September 30, 2025.

Based on the review and evaluation of the bids, the responsible bidder with the lowest responsive base bid for the service was determined to be Manteca Ford -Mercury, Inc., with a base bid of $570, 172. 69.

BACKGROUND:

Staff released specifications for bid solicitations for the purchase of fleet vehicles on September 16, 2025, pursuant to PCC 20160 and LMC 2. 36. 060. Two ( 2) bids were received and opened by the City Clerk on September 30, 2025, and one ( 1) bid was determined to be a responsive responsible bidder. The bid result is summarized in Table 1 below:

Table 1: Summary of Bid Results — Purchase of Fleet Vehicles Contractor Base Bid
Manteca Ford -Mercury, Inc. 5570, 172. 69
Winner Chevrolet, Inc. Non -Responsive
The specifications for bid solicitations included nine ( 9) vehicles as detailed below.

Public Works / Building - One ( 1) Ford Ranger Truck
Ford Ranger Super Crew ( 4 full sized doors), V6, 4x2 truck, white in color, side mount toolboxes, amber and white emergency light bars with an in -cab controller ( lightbar must have flashing and directional options), six amber and white flashing perimeter lights ( 2 in front grill, 1 on each side of the vehicle front quarter panel, and 1 on each side of the vehicle rear quarter panel), spray on bed liners, and headache rack.

Public Works / Maintenance Services - Two ( 2) Ford F- 150 Super Crew Trucks Ford F- 150 Super Crew ( 4 full sized doors), V8, 4x4 truck, white in color with running boards, lumber rack, toolbox under the rear window, Weather Guard Pack Rat ( or equivalent) slide out toolbox, amber and white emergency light bars with an in -cab 499

CITY MANAGER' S REPORT
OCTOBER 13, 2025 CITY COUNCIL REGULAR MEETING
APPROVE THE PURCHASE OF NINE ( 9) FLEET VEHICLES
PAGE 2
controller ( lightbar must have flashing and directional options), six amber and white flashing perimeter lights ( 2 in front grill, 1 on each side of the vehicle front quarter panel, and 1 on each side of the vehicle rear quarter panel), spotlights, spray on bed liner, and headache rack.

Public Works / Utilities - Two ( 2) Ford F- 250 Super Cab Trucks Ford F- 250 Super Cab ( 2 full sized doors, 2 half doors), V8, 4x4 truck, white in color with running boards, utility bed, amber and white emergency light bars with an in - cab controller ( lightbar must have flashing and directional options), six amber and white flashing perimeter lights ( 2 in front grill, 1 on each side of the vehicle front quarter panel, and 1 on each side of the vehicle rear quarter panel), spray on bed liner, and headache rack.

Public Works / Utilities - One ( 1) Ford F- 250 Super Cab Truck with Liftgate Ford F- 250 Super Cab ( 2 full sized doors, 2 half doors), V8, 4x4 truck, white in color with running boards, utility bed, ladder rack, amber and white emergency light bars with an in - cab controller ( lightbar must have flashing and directional options), six amber and white flashing perimeter lights ( 2 in front grill, 1 on each side of the vehicle front quarter panel, and 1 on each side of the vehicle rear quarter panel), spray on bed liner, headache rack and a lift gate.

Police Department / Community Services - One ( 1) Ford F- 150 Police Responder Trucks
Ford F- 150 Police Responder Pickup, black in color, with dual factory - installed spot lamps.

Police Department / Community Services - Two ( 2) Ford Expedition Max SUV' s Ford Expedition/ MAXSpecial Service Vehicles, black in color.

Staff reviewed and evaluated the bids and determined that the lowest responsible bidder is Manteca Ford - Mercury, Inc., with a base bid of $570, 172. 69. Staff requests City Council adopt a resolution to award the purchase of nine ( 9) fleet vehicles to Manteca Ford - Mercury, Inc.

RECOMMENDATION:

Staff requests City Council to approve the proposed base bid of $ 570, 172. 69 for the purchase of nine ( 9) fleet vehicles with Manteca Ford - Mercury, Inc.

FISCAL IMPACT:

The total proposed purchase of fleet vehicles from Manteca Ford - Mercury, Inc., is not to exceed $ 520, 172. 69. Sufficient funds were allocated in the approved Fiscal Year FY) 2025/6budget for the purchase of fleet vehicles.
500

CITY MANAGER' S REPORT
OCTOBER 13, 2025 CITY COUNCIL REGULAR MEETING
APPROVE THE PURCHASE OF NINE ( 9) FLEET VEHICLES
ATTACHMENTS:

PAGE 3
A. Resolution to Approve the Purchase of Nine ( 9) Fleet Vehicles from Manteca Ford -Mercury, Inc.

B. Bid Proposal from Manteca Ford -Mercury, Inc.
501

CITY MANAGER' S REPORT
OCTOBER 13, 2025 CITY COUNCIL REGULAR MEETING
APPROVE THE PURCHASE OF NINE ( 9) FLEET VEHICLES
APPROVALS:

Todd
4O
Sebas tmr Date
Director of Parks, Recreation, and Fleet
0,4 /7 a7
Thomas Hedegard Date
Deputy City Manager
MI
Mich I King Date
Assistant City Manager
O. 3. to -1--' S
Salvador Navarrete Date
City Attorney

8.1.35 Stephen ]. Salvatore Date
City Manager
PAGE 4
502
RESOLUTION NO. 25-

A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF LATHROP TO APPROVE PURCHASE OF NINE ( 9) FLEET VEHICLES FROM MANTECA FORD - MERCURY, INC.

WHEREAS, on September 16, 2025, staff released specifications for bid solicitations for the Purchase of Fleet Vehicles; and
WHEREAS, on September 18, 2025, the City solicited bids for the Purchase of Fleet Vehicles pursuant to PCC 20160 and LMC 2. 36. 060; and WHEREAS, a total of two ( 2) bids were received and opened by the City Clerk on September 30, 2025; and
WHEREAS, upon review and evaluation of the bids, the responsible bidder who submitted the lowest responsive bid for the purchase of nine ( 9) fleet vehicles was determined to be Manteca Ford - Mercury, Inc., with a base bid of $570, 172. 69; and
WHEREAS, staff requests City Council approve the purchase of nine ( 9) fleet vehicles from Manteca Ford -Mercury, Inc., in the amount of $ 570, 172. 69; and Vehicle Cost
Ford F- 250 Super Cab ( 2 full sized doors, 2 half
doors), V8, 4x4 truck, white in color with running
boards, utility bed, ladder rack, amber and white
emergency light bars with an in - cab controller
lightbar must have flashing and directional
options), six amber and white flashing perimeter
lights ( 2 in front grill, 1 on each side of the vehicle front quarter panel, and 1 on each side of the
vehicle rear quarter panel), spray on bed liner,
headache rack and a lift gate.

Ford F- 250 Super Cab ( 2 full sized doors, 2 half
doors), V8, 4x4 truck, white in color with running
boards, utility bed, ladder rack, amber and white
emergency light bars with an in -cab controller
lightbar must have flashing and directional
options), six amber and white flashing perimeter
lights ( 2 in front grill, 1 on each side of the vehicle front quarter panel, and 1 on each side of the
vehicle rear quarter panel), spray on bed liner,
headache rack and a lift gate.
41, 820. 54 (1)
62, 924.8
125, 849. 96 (2)
503
Ford F- 250 Super Cab ( 2 full sized doors, 2 half
doors), V8, 4x4 truck, white in color with running
boards, utility bed, amber and white emergency
light bars with an in -cab controller ( lightbar must
have flashing and directional options), six amber
and white flashing perimeter lights ( 2 in front grill, 1 on each side of the vehicle front quarter panel,
and 1 on each side of the vehicle rear quarter
panel), spray on bed liner, and headache rack.
69, 039. 9
138, 079. 98 (2)
Ford F- 250 Super Cab ( 2 full sized doors, 2 half
doors), V8, 4x4 truck, white in color with running
boards, utility bed, ladder rack, amber and white
emergency light bars with an in -cab controller
lightbar must have flashing and directional
options), six amber and white flashing perimeter
lights ( 2 in front grill, 1 on each side of the vehicle front quarter panel, and 1 on each side of the
vehicle rear quarter panel), spray on bed liner,
headache rack and a lift qate.
76, 877. 30 (1)
Ford F- 150 Police Responder Pickup, black in color,
with dual factory - installed spot lamps.
531398. 0 (1)
Ford Expedition/ Max Special Service Vehicles black
in color
67, 073. 41
134,6. 82 (2)
Total 570, 172. 69
WHEREAS, the total proposed purchase of nine ( 9) fleet vehicles from Manteca Ford -Mercury, Inc., is not to exceed $ 570, 172. 69. Sufficient funds were allocated in the approved Fiscal Year ( FY) 2025/026 budget for the purchase of fleet vehicles;
NOW, THEREFORE, BE IT RESOLVED, that the City Council of the City of Lathrop hereby approves the purchase of nine ( 9) fleet vehicles from Manteca Ford - Mercury, Inc., for a total cost not to exceed $ 570, 172. 69. 504
The foregoing resolution was passed and adopted this 13th day of October, 2025 by the following vote of the City Council, to wit:

AYES:

NOES:

ABSTAIN:

ABSENT:

Sonny Dhaliwal, Mayor
ATTEST: APPROVED AS TO FORM:

S
Teresa Vargas, City Clerk Salvador Navarrete, City Attorney 505

ATTACHMENT B
7) 4it Ware o tea

MANT( CA
kaad E . diae
ZUlcete de Veal
555 North Main Street • P. O. Box 2185 • Manteca, California 95336 09/ 26/025
Please see the quote below for the City of Lathrop.
209) 239- 3561

1. One ( 1) 2026 F- 250 4x4 Supercab V8 with Lift and Ladder Rack: $ 76, 877. 30

2. Two ( 2) 2026 F- 250 4x4 Supercab V8 w/ out lift: $69, 039. 99x2 $138, 079. 98

3. Two ( 2) 2026 F- 150 4x4 Crew Cab V8 $ 62, 924.8x2 $125, 849. 96

4. One ( 1) 2025 Ford Ranger Crew $ 41, 82054

5. One ( 1) 2026 Ford F- 150 (Police) $53, 398. 09

6. Two ( 2) 2026 Ford Expedition $ 67, 073. 41x2 $134,6. 82 Total: $570, 172. 69
All prices include California Sales tax
If you have any questions, please contact me.

Jeff Houghton
GSM
Manteca Ford
209-71- 6645
Where Customer Satisfaction is our Business"
506
SECTION 00300
FY 2025-026 Bid #1 for Purchase of Fleet Vehicles BID PROPOSAL FORMS FY 2025-026

PURCHASING FLEET VEHICLES
yehicte Description.

The City of Lathrop anticipates purchasing nine (9) vehicles which must be a new2025 or 2026 model as specified below:

Delivery date Is an evaluation factor. Be realistic on your dates. You wilt be evaluated based on the timeframeyou indicate and held to it.

Failure to meet the promised date may be considered a breach of contract and the order cancelled.

All rates and fees must be listed on the proposal cost sheet. The city will not be responsible for paying any fees not specifically listed. The fees and charges presented shall remain firm for the original term of the agreement.

The City of Latrhop is a local government and therefore exempt from registration fees and taxes. All registration paperwork relating to obtaining the title and license plates for vehiclesshatl be listed as a governmnet vehicles.

Warrantywitt begin no sooner than following delivery of the vehicie( s) to 390 Towne Center Drive, Lathrop, CA 95330 Ford Ranger Super Crew (4 full Sized doors), V6, 4x2 truck, white in color, side mount toolboxes, amber and white emergency tight bars With an in -cab controller ( tightbar must have flashing and directional options), six amber and white flashing perimeter tights ( 2 in front grill, 1o each side of the vehicle front quarter panel, and 1 on each side of the vehicle rear quarter panel), spray on bed liners, and headache rack.
y , SN
Os DAD • 1
Sy
elliI
O. Xi,.. 10 wec ks
Ford F- 150 Super Crew (4 full sized doors), V8, 4x4truck, white in color with running boards, lumber rack, toolbox under the rear window, Weather Guard Pack Rat ( or equivalent) slide out toolbox, amber and white emergency light bars with an in -cab controller tightbar must have flashing and directional options), six amber and hit flashing perimeter lights ( 2 in front grill, 1 on each side of the vehicle front quarter panel, and 1 on each side of the vehicle rear quarter panel), spotlights, spray on bed liner, and headache rack. 41 y
4 I
2 e
Hi X 2,
I() w ee S
r$
Ford F- 250 Super Cab ( 2 full sized doors, 2 hatf doors), V8, 4x4 truck, white in color with running boards, utility bed, amber and white emergency light bars with an in - cab controlter ( lightbar must have qg
flashing and direct ionaloptions), six amber and white flashing perimeter lights ( 2 in front grill, 1 on each side of the vehicle front quarter panel, and 1 on each side of the vehicle rear quarter panel), spray on bed liner, and headache rack.
4, 9Pal,— 2
qi

1. 3g On 41,.

34. "'eGkS
Ford F- 250 Super Cab j2 futt sized doors, 2 half doors), V8, 4x4 truck, white in color with running boards, utility bed, ladder rack, amber and white emergency light bars with an in -cab controller ( tightbr must have flashing and directional options), six amber and white flashing perimeter lights ( 2in front grill, 1 on each side of the vehicle front quarter panel, and l on each side of the vehicle rear quarter panel), spray on bed liner, headache rack and a rift gate.
30 7l. 5y77 1
yi
a rL
3W elcS
74 Ford F- 150 Police Responder Pickup, black in color, with duetfactoryinstalled spot lamps. p
1 sw X3 1
pO11 I O ( decks
Ford Expedition/ MAX Special Service Vehicles, black in color. l,p. w 2 13411 yLP. XL IOW Ce kS 9 TOTAL BIDS V S 7Q ) 11.) •
TOTAL BID IN WORDS: Fi Ve. flUAcreel SedsA1' ytkou gad
ont H„ t4ec caand SawsAt), } Ida
DoltcirS & Ad G° icents
00300- 3
507
SECTION 00300
FY 2025-026 Bid #1 for Purchase of Fleet Vehicles BID PROPOSAL FORMS

INFORMATION REQUIRED OF BIDDER
The Bidder shall furnish the following information. This information is considered essential in enabling the Parks, Recreation, and Fleet Services Department Director to determine ifthe Bidder is experienced in similar types of work. Failure to comply with this requirement may render the Bid non -responsive and may cause its rejection. Additional sheets shall be attached as required.

BIDDER' SINFORMATION
1) Bidder' sname and address:

MG.' te. GG Ford
555 A1. nnein 5- t (I"AICcA CA- 45334
2)
3)
7)
Bidder' stelephone number: a09 - A 3't - 15( iI
Bidder' semail address: Jc, f4 tMTai. e H rttv Ai ! . (. 4 1 1 List 5 projects of a nature similar to this project:

Project Contract
Price
Name, Address and
Telephone Number of Owner
City of
1-e; ti b? 77) `"l
u 3440 T. id' G Ca t D . Or".
towrk ?Tor (.. A* ` t S3 U
C. i o
Y .# wrop IS l.oi. f
3q0 ' rownc ctn$ t1G prc. w tti roP cat O1 3 0
City of 440.t (C. 50 w 7. 61( 1 4tcCc
1004 W • GtnTc ogr ? A A
CA 4033c, sci- $1ar' A
GAY v 4. af1 t
yy1313
can* re, a
Ltfiftrr° 414. oP cR 4 ,. 30
Lity o4 incv1+ CC* 1 1' 11590 No i w. G isnrc r 5- r ' 1°- 4404tAris Cat later 415'- tIS
00300- 4
508
SECTION 00300
FY 2025-026Bid #1 for Purchase of Fleet Vehicles BID PROPOSAL FORMS LIST_ OF SUBCONTRACTORS:

The Bidder shall list below the name and business address of each subcontractor who will perform work under this Bid in excess of one- half of one percent ofthe Contractor' sTotal. Bid Price or ten thousand dollars ($ 10, 000), whichever is greater. Shall also list the portion of the WORK which will be done by such subcontractor, in accordance with Section 4104 of the Public Contract Code.

After the opening ofbids, no changes or substitutions will be allowed except as otherwise provided by law. The listing of more than one subcontractor for each item of work to be performed with the words " and/ oru will not be permitted. Failure to comply with this requirement may render the Bid non -responsive and may, cause its rejection.

Work
Perfor ed
3 bC0tiCra of '
N e
co Itractl r
Address
Percent of
Work
V ti
13eci
St; 14 5
Teovk
0 dy
701
s Gvtdsn
51414 atoll
Tu' LGk
CA
10 %
utlli ' Y
tied _
Ins
T"'`,
DIM
OIC vt
Sttsle blvd
MI-toc .

C A
l
a .0
6,
UTclty
13401, 4nc t.Ift _
S11% es
rc
00dy
701
S. Golden
rstc alVG1
rUf• 1OOk
C A
5' fo
4+ 14. S
Y
tol5, Wider. Iii c toGla
Lethrs sr: <<s
rti3do
Y
7O1
s• v0 (Glen
IL
rvet. ck
CA G
Note: Attach additional sheets ifrequired.
00300- 5
509
SECTION 00300
FY 2025-026 Bid # 1 for Purchase of Fleet Vehicles BID PROPOSAL FORMS

ADDENDA
Bidder certifies he reviewed City of Lathrop' s
website for addenda within 48 hours of bid opening
and acknowledges receipt of the following addendum ( addenda):

Respectfully submitted,

64. n -1- c ca Fo rd
Dated Legal Name ofFirm
Signatur Authorized Representative
Seal)
If Bidder is a corporation, show State in which incorporated.) The full names and post office addresses of all persons and parties interested in the foregoing Bid as principals are as follows:

NOTICE): Give first and last names in full; in case of corporation, give names of President, Secretary, Treasurer, and Manager, and in case ofpartnerships and joint ventures, give names and Post Office addresses of all the individual members.
ics- r oc,„ 31,, t.„ (, sin
phil wcterforai G. E. o
PIl; ! Lr Atc rc' Grol BIZ G (')
00300- 6
510
SECTION 00300
FY 2025-026 Bid # 1 for Purchase of Fleet Vehicles BID PROPOSAL FORMS

NON -COLLUSION AFFIDAVIT

STATE OF
ss.

COUNTY OF
4, H0020,,‘ , being first duly sworn, deposes and says that he or she is 1Vwnay Gr
of ( lce. n, tt 4q imp c4 the party making the foregoing bid that the bdis not made in the interest of, or on behalf of, any undisclosed person, partnership, company, association, organization, or corporation; that the bid is genuine and not collusive or sham; that the bidder has not directly or indirectly induced or solicited any other bidder to put in a false or sham bid, and has not directly or indirectly colluded, conspired, connived, or agreed with any bidder or anyone else to put in a sham bid, or that anyone shall refrain from bidding; that the bidder has not in any manner, directly or indirectly, sought by agreement, communication, or conference with anyone to fix the bid price ofthe bidder or any other bidder, or of that of any other bidder, or to secure any advantage against the public body awarding the contract of anyone interested in the proposed contract; that all statements contained in the bid are true; and, further, that the bidder has not, directly or indirectly, submitted his or her bid price or any breakdown thereof, or the contents thereof, or divulged information or data relative thereto, or paid, and will not pay, any fee to any corporation, partnership, company associated, organization, bid depository, or to any member or agent thereof to effectuate a collusive or sham bid.

Signature of: Pre cretary, Manager, or
Representative
The County of $ A^ l
t
State of CA
Subscribed and sworn to ( or affirmed) before me
on this & day of Sepjge'# ber , 20., 1, by
proved to
me on the basis of satisfactory evidence to be the
person( s) who appeared before me.

Seal
Signature
00300- 7
511
SECTION 00300
FY 2025-026 Bid #1 for Purchase of Fleet Vehicles BID PROPOSAL FORMS PUBLIC CONTRACT CODE SECTION 10162 QUESTIONNAIRE
In accordance with Public Contract Code Section 10162, the Bidder shall complete, under penalty of perjury, the following questionnaire:

Has the Bidder, any officer of the Bidder, or any employee of the Bidder, who has a proprietary interest in the Bidder, ever been disqualified, removed, or otherwise prevented from bidding on, or completing a federal, state, or local government project because of a violation of law or a safety regulation? Yes No X
If the answer is yes, explain the circumstances in the following space.

PUBLIC CONTRACT SECTION 10232 STATEMENT
In accordance with Public Contract Code Section 10232, the Contractor hereby states under penalty of perjury, that no more than one final unappealable finding of contempt of court by a federal court has been issued against the Contractor within the immediately preceding two year period because ofthe Contractor' sfailure to comply with an order of a federal court which orders the Contractor to comply with an order of the National Labor Relations Board.

NOTE: The above Statement and Questionnaire are part of the Proposal. Signing this proposal on the signature portion thereof shall also constitute signature of this Statement and Questionnaire.

Bidders are cautioned that making a false certification may subject the certifier to criminal prosecution.
00300- 8
512
SECTION 00660
FY 2025-026 Bid #1 for Purchase of Fleet Vehicles WORKER' SCOMPENSATION CERTIFICATION

WORKER' SCOMPENSATION CERTIFICATION
AS REQUIRED BY SECTION 1861

OF THE CALIFORNIA LABOR CODE)
I am aware of the provision of Section 3700 of the Labor Code which require every employer to be insured against liability for worker' s
compensation or to undertake self- insurance in accordance with the provisions of that code, and I will comply with such provisions before commencing the performance ofthe work of the Contract.

Contractor:

By:

Title:

La1 fc Ca Fo f`d
6 + 0
SM

END OF SECTION)
00660- 1
513
SECTION 00300
FY 2025-026 Bid #1 for Purchase of Fleet Vehicles BID PROPOSAL FORMS

AFFIRMATIVE ACTION PROGRAM CERTIFICATE
The Bidder hereby certifies that Bidder is in compliance with the Civil Rights Act of 1964, Executive Order No. 11246, and all other applicable Federal and State laws and regulations relating to equal opportunity employment.

BIDDER
Signature)
f/ G/ aS
Date)
Bidder' sName:

Address:

Mc ittcc4 Fo d
S" A . Mot A . 5" t
Yl c r) teas C as` 3,
The above certification of the Bidder regarding its affirmative action program shall be filled out completely, signed, and submitted by each Bidder and shall be a part of the Contract Documents.)

END OF SECTION)
00300- 9
514
ITEM 4. 10

CITY MANAGER' S REPORT
OCTOBER 13, 2025 CITY COUNCIL REGULAR MEETING
ITEM: APPROVE TITLE VI OF THE CIVIL RIGHTS ACT OF
1964 IMPLEMENTATION PLAN FOR THE CITY OF

LATH RO P
RECOMMENDATION: Adopt Resolution to Approve a Title VI Non - Discrimination Policy Implementation Plan in
Compliance with the Civil Rights Act of 1964 for the
City of Lathrop
SUMMARY:

Compliance with Title VI of the Civil Rights Act of 1964 is a requirement for the City of Lathrop to receive federal funding for transportation projects. To maintain its eligibility for financial assistance, the City must adopt the attached resolution approving the Title VI Implementation Plan and complete a Title VI Program Assessment Online Form by December 2025. The Title VI Program outlines policies and procedures to ensure transportation projects do not discriminate against, or place undue burdens on, protected classes.

BACKGROUND:

The City of Lathrop receives federal highway funds for transportation projects. To maintain eligibility for these funds, the City must adopt the attached resolution approving the Title VI Implementation Plan and complete the Title VI Program Assessment Online Form by December 2025.

Staff have prepared the attached Title VI Implementation Plan using available online resources. The Plan includes the following Non -Discrimination Policy Statement:

The City of Lathrop certifies it is committed to ensuring compliance with Title VI of the Civil Rights Act of 1964 and other non- discriminatory authorities, such that no person shall be excluded from participation in or be denied the benefits of any program or activity conducted by the City of Lathrop on the grounds of race, color, national origin, sex, age, disability, religion, sexual orientation, gender identity, or any other category protected by State or Federal law.

Further, no person shall be subjected to discrimination under any program or activity conducted by the City of Lathrop, on the grounds of race, color, national origin, sex, age, disability, religion, sexual orientation, gender identity, or any other category protected by State or Federal law.

In accordance with Federal Highway Administration ( FHWA) and Caltrans guidelines, the Plan also includes sections on Non -Discriminatory Legislation, Organization Structure, Complaint Procedure, Title VI Outreach and Resources, Data Collection 515

CITY MANAGER' S REPORT
OCTOBER 13, 2025 CITY COUNCIL REGULAR MEETING

APPROVE TITLE VI PROGRAM FOR THE CITY OF LATHROP
PAGE 2
and Analysis, Contract Documents and Agreements, Training, Annual Work Plan, and an Appendix with a Limited English Proficiency Plan, Notice to the Pubic, Complaint Form and assurances from the US Department of Transportation.

RECOMMENDATION:

Compliance with Title VI of the Civil Rights Act of 1964 is a requirement for the City of Lathrop to receive federal funding for transportation projects. Staff recommend that Council adopt the attached resolution approving the Title VI Implementation Plan for the City of Lathrop.

FISCAL IMPACT:

There are no immediate costs to the City associated with this action, aside from staff time required to implement the Title VI Plan. Compliance with Title VI of the Civil Rights Act of 1964 is necessary to maintain eligibility for federal transportation funding. The estimated staff time needed for ongoing implementation will be incorporated into future operating budget plans.

ATTACHMENTS:

A. Resolution to Approve a Title VI Program for the City of Lathrop B. City of Lathrop Title VI Program, October 2025
516

CITY MANAGER' S REPORT
OCTOBER 13, 2025 CITY COUNCIL REGULAR MEETING

APPROVE TITLE VI PROGRAM FOR THE CITY OF LATHROP
APPROVALS:

45. 0-
Greg C3ybson Date
Senior Civil Engineer
Brad ylor
City ngineer
Juliana Bur
Human Resources Director
Date
6146407 -c --
9/ 7} i/vac
1/0/ Zorc
Date
Michael King Date
Assistant City Manager

1.- I1- ZozS
Salvador Navarrete Date
City Attorney
Step en J. Salvatore Date
City Manager
PAGE 3
517
RESOLUTION NO. 25 -

A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF LATHROP TO

APPROVE A TITLE VI NON- DISCRIMINATION POLICY IMPLEMENTATION PLAN IN COMPLIANCE WITH THE CIVIL RIGHTS ACT OF 1964 FOR THE CITY

OF LATHROP
WHEREAS, compliance with Title VI of the Civil Rights Act of 1964 is a requirement for the City of Lathrop to receive federal funding for transportation projects; and
WHEREAS, in order to maintain its eligibility for federal financial assistance, the City must adopt the attached resolution to approving the Title VI Implementation Plan and complete a Title VI Program Assessment Online Form by December 2025; and
WHEREAS, the Title VI Program outlines policies and procedures to ensure transportation projects do not discriminate or place undue burdens on protected classes; and
WHEREAS, staff have prepared a Title VI Implementation Plan for Lathrop using online resources; and
WHEREAS, there are no immediate costs to the City associated with this action aside from staff time for implementation of the Title VI Plan.

NOW THEREFORE, BE IT RESOLVED, the City Council of the City of Lathrop does hereby approve the Title VI Implementation Plan that accompanied the staff report for this resolution.
518
The foregoing resolution was passed and adopted this 13th day of October 2025, by the following vote of the City Council, to wit:

AYES:

NOES:

ABSENT:

ABSTAIN:

Paul Akinjo, Mayor
ATTEST: APPROVED AS TO FORM:

Teresa Vargas, City Clerk Salvador Navarrete, City Attorney 519
Attachment B

CITY OF LATHROP

TITLE VI IMPLEMENTATION PLAN
Adopted October 13, 2025
520
Table of Contents
Non -Discrimination Policy Statement 1
Non -Discriminatory Legislation 2
Organization Structure 3
Title VI Coordinator 3
Assistant Title VI Coordinator 3
Title VI Specialist 3
Title VI Liaison 4
Title VI Organization Chart 4
Complaint Procedure 5
Complaints Processed Under the Federal Highway Administration 5 Ca! trans OCR Investigation Process 6
Title VI Outreach and Resources 7
Limited English Proficiency 7
Title VI Information Dissemination 7
Environmental Justice 8
Data Collection and Analysis 8
Contract Documents and Agreements 8
Training 9
Annual Work Plan 9
Appendix 10
A. Limited English Proficiency Plan 10
B. Notice to Public 13
C. Complaint Form 14
D. US DOT Title VI Assurances A -E 16
521
Non -Discrimination Policy Statement
The City of Lathrop Public Works Department is committed to ensuring compliance with Title VI of the Civil Rights Act of 1964 and other non- discriminatory authorities, such that no person shall be excluded from participation in or be denied the benefits of any program or activity conducted by the City of Lathrop Public Works Department on the grounds of race, color, national origin, sex, age, disability, religion, sexual orientation, gender identity, or any other category protected by State or Federal law.

Further, no person shall be subjected to discrimination under any program or activity conducted by the City of Lathrop Public Works Department, on the grounds of race, color, national origin, sex, age, disability, religion, sexual orientation, gender identity, or any other category protected by State or Federal law.

Title VI compliance is a condition of receipt of federal funds. The Title VI Coordinator is authorized to ensure compliance with this policy, Title VI of the Civil Rights Act of 1964, 42 U. S. C § 2000d and related statutes, and the requirements of 23 Code of Federal Regulation ( CFR) pt. 200 and 49 CFR pt. 21.

Michael King Date
Assistant City Manager, City of Lathrop
Title VI Implementation Plan
City of Lathrop
1 522
Non -Discriminatory Legislation
Title VI of the Civil Rights Act of 1964 — Provides that no person in the United States shall, on the grounds of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be subjected to discrimination, under any program or activity receiving Federal financial assistance ( as implemented through 23 CFR 200. 9 and 49 CFR 21).

Section 162( a) of the Federal -Aid Highway Act of 1973 ( Section 324, Title 23 U. S. C.) — Prohibits discrimination on the basis of sex by recipients and sub -recipients of Federal financial assistance.

Section 504 of the Rehabilitation Act of 1973 — Prohibits discrimination on the basis of disability by recipients and sub -recipients of Federal financial assistance.

The Age Discrimination Act of 1975 ( Section 6101-107, Title 42 U. S. C.) — Prohibits discrimination on the basis of age by recipients and sub -recipients or Federal financial assistance.

The Civil Rights Restoration Act of 1987 ( Public Law 200- 209) — Clarifies that the original intent of Congress in Title VI of the Civil Rights Act of 1964, Title IX of the Educational Amendments of 1972, the Age Discrimination Act of 1975, and Section 504 of the Rehabilitation Act of 1973 was to apply the non- discrimination statutes to all programs and activities of Federal - aid recipients, sub -recipients, contractors and vendors, whether all such programs are federally assisted or not.

Executive Order 12898 ( issued February 11, 1994) — Addresses Environmental Justice regarding minority and low- income populations and requires agencies to develop strategies to address disproportionately high and adverse human health or environmental effects of their programs on minority and low- income populations; promote nondiscrimination in federal programs substantially affecting human health and the environment; and provide minority and low- income communities access to public information and an opportunity for public participation in matters relating to human health or the environment.

Executive Order 13166 ( issued August 16, 2000) — Addresses improved access to services for persons with limited English proficiency. Agencies are directed to evaluate services provided and implement a system that ensures that Limited English Proficiency ( LEP) persons are able to meaningfully access the services provided consistent with, and without unduly burdening, the fundamental mission of the local agency. Agencies are directed to ensure that recipients of federal financial assistance provide meaningful access to program, services and information to their LEP applicants and beneficiaries free of charge.

Title VI Implementation Plan
City of Lathrop
2 523
Organization, Staffing and Structure
The City of Lathrop' s Title VI program is a multi -tiered program in which multiple roles work toward the ultimate goal of assuring full compliance with the provisions of Title VI of the Civil Rights Act of 1964 and related statutes. The City has assigned the roles of Title VI Coordinator, Assistant Title VI Coordinator, Title VI Specialist and Title VI Liaison to designated individuals in the Public Works and Human Resources Departments.. Their specific roles and responsibilities are as follows:

Title VI Coordinator ( Assistant City Manager/ City Engineer):

Maintains a direct line of communication with City Manager, City Council, City Leadership positions
Assistant Title VI Coordinator ( HR):

Develops, Plans and Coordinates Training for managers, supervisions and staff with frequent public contact.

Collects Demographic Data from US Censor
Have a readily available list of certified translators and provide list to staff with frequent public contact
Title VI Specialist ( Public Works: Assistant Engineer):

Prepares and coordinates Title VI plan and annual report submissions Develops Title VI information for dissemination to the public Ensures Title VI Assurances have been incorporated into all Federal -aid Contracts and Agreements
Prepares annual reports
Processes Complaints after received ( no more than 180days). Should go to Legal and Risk Management as soon as a complaint is received
Title VI Liaison ( HR risk management; Public Works: Assistant Engineer/ Management Analyst/ Project Manager):

Works directly with contractors, public, counter
Reports complaints through complaint procedures
Key Responsibilities ( assigned to entire group as a whole):

Program Implementation:

Leading the development and implementation of the organization' sTitle VI program and procedures.

Monitoring and Compliance:

Monitoring all federal -aid programs, activities, and services for compliance with Title VI requirements and preparing annual reports.

Title VI Implementation Plan
City of Lathrop
3 524
Complaint Resolution:

Receiving, investigating, and resolving formal and informal complaints of discrimination.

Data Collection:

Collecting and analyzing demographic data of participants in federally funded programs and services.

Guidance and Training:

Providing technical assistance, guidance, and training to staff, regional offices, and sub -recipients on Title VI requirements.

Public Outreach:

Ensuring public information is available in other languages when needed and participating in public involvement activities to ensure adequate representation of all groups.

Risk Assessment:

Conducting periodic Title VI audits and risk assessments to identify and address potential deficiencies or conflicts.

Reporting:

Preparing and submitting annual reports on Title VI accomplishments, goals, and any identified issues to the agency administrator and relevant federal bodies.

Program Implementation:

Leading the development and implementation of the organization' sTitle VI program and procedures.

Monitoring and Compliance:

Monitoring all federal -aid programs, activities, and services for compliance with Title VI requirements and preparing annual reports.

Complaint Resolution:

Receiving, investigating, and resolving formal and informal complaints of discrimination.

Data Collection:

Collecting and analyzing demographic data of participants in federally funded programs and services.

Guidance and Training:

Title VI Implementation Plan
City of Lathrop
4 525
Providing technical assistance, guidance, and training to staff, regional offices, and sub -recipients on Title VI requirements.

Public Outreach:

Ensuring public information is available in other languages when needed and participating in public involvement activities to ensure adequate representation of all groups.

Risk Assessment:

Conducting periodic Title VI audits and risk assessments to identify and address potential deficiencies or conflicts.

Reporting:

Preparing and submitting annual reports on Title VI accomplishments, goals, and any identified issues to the agency administrator and relevant federal bodies.

Organizational Chart
Title VI
Coordinator
Michael King, Brad Taylor
Title VI
Liaison
Carlos Carillo
Title VI
S•- •.Ii t
Angel Abarca
Title VI
Liaison
Leisser Mazarigos
Title VI Implementation Plan
City of Lathrop
5 Asst. Title VI
Coordinator
Juliana Burns
Title VI
Liaison
Angel Abarca
526
Complaint Procedure
The City of Lathrop Public Works Department is committed to ensuring compliance with Title VI of the Civil Rights Act of 1964 and other non- discriminatory authorities, such that no person shall be excluded from participation in or be denied the benefits of any program or activity conducted by the City of Lathrop Public Works Department on the grounds of race, color, national origin, sex, age, disability, religion, sexual orientation, gender identity, or any other category protected by State or Federal law.

Any person that believes they have been discriminated against on the grounds of race, color, national origin, sex, age, disability, religion, sexual orientation, gender identity, or any other category protected by State or Federal law by the City of Lathrop' sPublic Works Department, its contractors, consultants or any other party that acts on behalf of the Public Works Department may file a Title VI complaint by completing and submitting the City' s Title VI Complaint Form ( Appendix C), which can be found displayed in the City Hall lobby, and online at « Insert Link» .

The City' sTitle VI Specialist processes complaints received no more than 180 days after the alleged incident. The Title VI Specialist will only process complaints that are complete, which include at a minimum, the following:

Complainant' scontact information
Date of alleged act of discrimination
Details of the alleged discrimination
The complainant' ssignature
Once the Title VI complaint is received, the Title VI Specialist will forward the complaint to Caltrans, to be submitted to the FHWA Division Office. The Title VI Specialist will also begin processing the complaint by entering said complaint into the City' s Title VI Discrimination Complaint Log, and conducting an internal investigation. Once a finding has been determined/ received, the City' sTitle VI Specialist will provide said finding to the complainant within ten business days via letter and/ or email.

Complaints Processed Under the Federal Hiahwav Administration Title VI complaints filed with Caltrans in which Caltrans is named as the Respondent will be forwarded to the FHWA Division Office. The Complainant will receive an acknowledgement letter informing them that the complaint has been received and forwarded to the FHWA.

Per the FHWA Guidance Memorandum, Processing of Title VI Complaints, dated June 13, 2018, all Title VI complaints received by a sub -recipient (City of Lathrop) are to be forwarded to Caltrans to be submitted to FHWA Division Office. Complaints should be sent within one business day of receipt via email to Title. Vl@dot. ca. gov. If Headquarters Office of Civil Rights ( HCR) determines a Title VI complaint against a sub -recipient can Title VI Implementation Plan
City of Lathrop
6 527
be investigated by Caltrans, HCR may delegate the task of investigating the complaint to Caltrans.

Ca trans OCR Investiaation Process
If OCR is delegated the responsibility of performing an investigation, OCR has 90 days to investigate the complaint. If additional time is needed, OCR will call the Complainant and inform them.

If more information is needed to resolve the case, the OCR investigator may contact the Complainant. The Complainant has ten business days from the date of the letter to send the requested information to the investigator assigned to the case.

If the investigator is not contacted by the Complainant or does not receive the additional information within ten business days, OCR can administratively close the case. A case can be administratively closed also if the complainant no longer wishes to pursue their case
OCR with consult with HCR regarding the disposition of the complaint. Disposition of Title VI complaint will be undertaken by HCR, through either ( 1) informal resolution or (2) issuance of a Letter of Finding of compliance or noncompliance with Title VI. A copy of the Letter of Finding will be sent to all parties via the Division Office.

A person may also file a complaint directly with the FHWA and/ or Caltrans by the following contact information:

Federal Highway Administration
U. S. Department of Transportation
Office of Civil Rights
1200 New Jersey Avenue, SE
8th Floor E81- 104
Washington, DC 20590
California Department of Transportation
Office of Civil Rights
Attention: Title VI Program Branch
1823 14th Street, MS 79
Sacramento, CA 95811
Title. VIa. dot. ca. gov
Should a complaint be filed with the City of Lathrop Public Works Department and one with a federal or state agency simultaneously, the federal/ state complaint will supersede the City' scomplaint and the City' scomplaint procedures will be suspended pending the federal/ state agency' sfindings.

Title VI Implementation Plan
City of Lathrop
7 528
Title VI Outreach and Resources
Table 1: Languages Spoken by City of Lathrop Residents
Language Spoken
Group
Population
Group' s
Percentage
of
Population
Portion of
Group that
Speaks
English Very
Well
Portion of
Group That
Does Not
Speak English
Ver Well
English Only
Spanish
Other Indo- European
Lan. ua• es
Asian and Pacific Island
Lan• uages
Other Languages
Total Population Above 5 Years
5772
4384 14. 5 2360 ( 53. 8%) 2024 ( 46. 2%)
9 30189

19. 0 3994 ( 68. 9%)1778 ( 31. 1%)
66 6.%)
25215 (83. 5%) 4974 ( 16. 5%)
Source: US Census: American Community Survey 2019-023 5 -Year Estimate https:// data. census. gov/ table/ ACSST5Y2023. S 1601 ? q=Lathrop,+ CA+ Language Limited English Proficiency
A Limited English Proficiency ( LEP) person is a person that does not speak English as a primary language and has a limited ability to read, write, or comprehend English. Per Executive Order 13166, agencies which receive Federal funding must examine their Federally -funded services and develop and implement processes that will allow LEP persons to meaningfully access said services. Executive Order 13166 also requires that agencies receiving Federal funding must establish guidance for providing meaningful access to LEPs, prepare a plan to overcome language barriers in Federally -funded programs and activities, and ensure that stakeholders have adequate opportunity to provide input.

As shown in Table 1 above, 16. 5% of residents in the City of Lathrop are considered LEP persons, with the majority of those LEP persons primarily speaking Spanish ( 19% of the community), Other Indo- European Languages ( 12. 2% of the community), Asian and Pacific Island Languages ( 14. 5% of the community) and Other Languages ( 0.7% of the community). As outlined in the City' s LEP Plan ( Appendix A), the City has conducted an LEP Needs Assessment, using a Four Factor Analysis to identify need and provide access to the LEP community in compliance with Executive Order 13166.

Title VI Information Dissemination
In order to ensure that Title VI and related Civil Rights information is readily available to the public, the City will develop public notices consisting of posters, flyers, complaint forms and " I Speak" cards that are available in English, Spanish, and Punjabi. The languages selected for the informational materials were based upon language data provided from the US Census; see Table 1 above. Said flyers and posters will be placed in the City Hall lobby, in a highly visible and accessible location. The public notices will also be available for viewing on the City' swebsite, at « Insert Link».

Title VI Implementation Plan
City of Lathrop
8 529
Environmental Justice
In accordance with Executive Order 12898 ( Federal Actions to Address Environmental Justice in Minority Populations and Low -Income Populations), City Staff will identify and address the environmental effects of programs, policies, and activities on minority and low- income populations for Federally -funded projects. Staff will consider demographic data during project design and involve the public in the planning and development process to assess the environmental impacts of projects on the community. The public' sinput and demographic data analysis will enable staff to develop measures to mitigate any potential adverse effects on minority and low- income populations.

Data Collection and Analysis
Demographic and related data collected and used by City staff comes from governmental sources responsible for collecting and vetting the information for consistency and accuracy. These sources include, but are not limited to, the U. S. Bureau of Labor Statics, U. S. Census Bureau, U. S. Bureau of Economic Analysis, California Department of Finance, California Department of Labor, and the California Employment Development Department.

Additionally, staff may also collect project -specific demographic data utilizing data collection as appropriate through the public outreach process on Federally -funded projects. Such outreach that may give Staff the opportunity to collect demographic data may include door hangers, posters, emails, social media releases, press releases to local newspaper, public meetings, virtual meetings, and public comment through websites generated for projects.

Contract Documents and Agreements
The City' s Title VI Specialist will ensure that any Federally -funded project documents contain the necessary Title VI Assurances and other language. Such assurances include, but may not be limited to:

FHWA Form 1273 ( Title VI and other non- discriminatory requirements) o Required on all FHWA contracts and subcontracts valued greater than 10, 000
Title VI Assurances Appendix A -E
o Appendix A -E to be attached to Federal -Aid contracts Additionally, City staff will include the provisions indicated in the "Administering Agency - State Agreement for Federal -Aid Projects Master Agreement" in the Local Assistance Program Manual ( LAPM) in contracts and agreements, where applicable, between the City and contractors.

The City will continue to utilize the " Local Agency Construction Contract Administration Checklist" (Exhibit 15- A of the LAPM), which confirms that DBE and labor/ Equal Title VI Implementation Plan
City of Lathrop
9 530
Employment Opportunity ( EEO) compliance requirements are performed and documented in the project files. Exhibit 15- Aof the LAPM documents that the local agency will meet all the requirements prior to the award of a construction contract.

Lastly, the City will continue to utilize the " Resident Engineer' s Construction Contract
Administration Checklist" (Exhibit 15- B of the LAPM) on federal -aid projects. The checklist assists in administering federal -aid highway construction projects and provides a record that the EEO/ Wage Rate/ False Statements posters are being posted at specific locations that employee interviews will be conducted in accordance with the Labor Compliance/ EEO interview form, and that DBE requirements are met. City staff will continue to submit Exhibit 15- B, along with the Award Package shortly after award of the construction contract.

Training
The City of Lathrop Human Resources Department will provide Title VI and related statute training to Public Works managers, supervisors, and staff with frequent public contact in the administration of federal -aid programs. These trainings will occur at minimum every two years, and within six months of hiring a new employee. The trainings will be conducted by the Title VI Specialist, online through presentations, or through trainings hosted by Caltrans. Additionally, links to Caltrans, FHWA, and other applicable agency resources for Title VI and related statutes will be posted on the City' s website at « Insert
Link».

In particular, the following items will be covered in trainings:

Review of Yuba City' s Title VI Implementation Plan and other relevant documents Language assistance services and " I Speak Cards" offered for public use How to handle potential complaints
Where to seek assistance for Title VI questions and concerns Annual Work Plan
The City of Lathrop Public Works Department will annually establish and monitor program goals and accomplishments. The Title VI Specialist will ensure that employee training is conducted, language translation services continue to be available, public participation is optimal, and appropriate Title VI signage is posted. This also includes updating community statistics and corresponding with state and federal agencies as necessary.

Title VI Implementation Plan
City of Lathrop
10 531
Appendix A

LIMITED ENGLISH PROFICIENCY PLAN
Backaround
Executive Order 13166, " Improving Access to Services for Persons with Limited English Proficiency" requires that Federal agencies work to ensure that the recipients of Federal financial assistance provide meaningful access to their Limited English Proficiency ( LEP) applicants and beneficiaries.

As such, local agencies are required to ensure that Federally - funded programs and activities normally provided in English are accessible to LEP Persons. Each local agency shall perform an annual assessment to determine if modifications are needed to their programs and activities to ensure meaningful access by LEP persons. The assessment which is referred to as a " Four - Factor" analysis is based on the following factors:

1. The number or proportion of LEP persons eligible to be served or likely to be encountered.

2. The frequency of LEP contacts.

3. The nature and importance of the programs, services, or activities provided by the City of Lathrop.

4. The resources available for LEP persons
The City of Lathrop is approximately 40 miles north of Sacramento and has a population of approximately 62, 000 (US Census: American Community Survey 2015-019 5 -Year Estimate).

Of the 62, 000 residents, approximately 20. 1% of the residents are Spanish speaking, and 18. 3% of the residents are Other Indo- European Language speaking. Based on the large Sikh population in Yuba City ( nearly 12, 000) it is safe to assume that the primary language of the Other IndoEuropean Languages listed in the Census is Punjabi.

Four -Factor Analysis

1. The number or proportion of LEP persons eligible to be served or likely to be encountered.

As shown in Table 1 below, the City of Lathrop has approximately 30, 189 residents. 16. 5% of residents in the City of Lathrop are considered LEP persons, with the majority of those LEP persons primarily speaking Spanish ( 19% of the community), Other Indo- European Languages

12. 2% of the community), Asian and Pacific Island Languages ( 14. 5% of the community) and Other Languages ( 0.7% of the community).

Title VI Implementation Plan
City of Lathrop
11 532
Table 1: Languages Spoken by City of Lathrop Residents
Language Spoken
Group
Population
Group' s
Percentage
of
Population
Portion of
Group that
Speaks
English Very
Well
Portion of
Group That
Does Not
Speak English
Ve Well
English Only
Spanish
Other Indo- European
Lan. ua• es
Asian and Pacific Island
Lan• uages
Other Languages
Total Population Above 5 Years
5772 19. 0 3994 ( 68. 9%)1778 ( 31. 1%)
4384 14. 5 2360 (53. 8%)2024 ( 46. 2%)

0. " ( 16i
30189 X 25215 ( 83. 5%) 4974 ( 16. 5%)
Source: US Census: American Community Survey 2019-023 5 -Year Estimate https:// data. census. gov/ table/ ACSST5Y2023. S1601 ?q=Lathrop,+ CA+ Language

2. The frequency of LEP contacts.

No data has been collected regarding frequency of contact with LEP persons at the City. Most interactions with LEP persons occur at the City' s Finance Department due to residents paying utility bills. Based on observation from Finance Department front -counter staff, the frequency for translation from Spanish to English is on average once per day. The frequency for translation from Punjabi to English is on average once per week. Currently the City' s Human Resources
Department retains a list which lists all City staff which are certified translators for various languages. If front counter staff that speak either Spanish or Punjabi are not available, City staff will reach out to a certified translator from the list.

Public Works staff does not regularly receive requests for translation through Federally funded programs/ projects, though the outreach components of said programs/ projects do typically have multi- lingual resources. Further, if translation services are needed, staff will provide said translation in a timely manner.

3. The nature and importance of programs, services, or activities provided by the City of Lathrop.

From observation provided by Public Works staff, it is rare that translation services are requested for programs, services, or activities which are Federally -funded. As stated above, the front counter Staff with the City' s Finance Department are the ones who most frequently encounter LEP persons requesting and/ or needing translation services.

Though Public Works Staff has received very few requests for translation services on Federally - funded projects, programs and services, Staff is keenly aware that almost twenty percent of the City' s residents are LEPs and therefore it is highly likely that LEPs will be stakeholder in any of the said projects, programs and services. As such, when Staff has encountered the need for translation services, Staff has provided the services readily.

Title VI Implementation Plan
City of Lathrop
12 533

4. The Resources Available for LEP persons.

After a review of the City' scurrently available resources for LEP persons, the City has determined that the current available resources are lacking and inconsistent. The City will remedy the lack of resources, through the action plan listed in the next section.

Action Plan
In order to ensure compliance with Title VI, and Executive Order 13166 the following publications and services will be made available for LEP person use:

Non -Discrimination Policy Statement
o Statement shall be printed in English, Spanish and Punjabi. Said statement will be posted in the City HaII lobby in a highly visible location.

Title VI Rights Poster
o Posters shall be printed in English, Spanish and Punjabi. Said posters will be posted in the City Hall lobby in a highly visible location, and additional copies will be available for the public to review and take.

Title VI Complaint Form
o Complaint forms shall be printed in English, Spanish and Punjabi. Said forms will be in the City Hall lobby in a highly visible location.

I Speak Cards
o I Speak Cards will be produced to easily identify translation services needed for English, Spanish, and Punjabi. Said cards will be placed at all public counters and with the other Title VI information.

Title VI Webpage on City' sWebsite
o All of the City' s Title VI resources will be posted on the City' s website at the
following link: « Insert Link».

Future Planning and Projects
o Public Works will ensure that all future projects and planning documents that are federally -funded utilize outreach methods that are compliant with Title VI and other related non- discriminatory assurances.
o Additionally, the City will ensure that outreach materials are available in English, Spanish, and Punjabi, and that translators are readily available as necessary for any LEP Persons that would like to contribute or participate.

Lastly, the Title VI Specialist will request an updated list of certified translators from the Human Resources Department every six months, and distribute said list to those who are likely to encounter LEP persons, such that a translator can be contacted the moment one is needed.

To ensure continuous compliance, the City will review the Title VI Implementation Plan and Limited English Proficiency Plan regularly, but at a minimum, as new data from the US Census becomes available. As new regulations are created, the City will act promptly to update the existing plans and relevant resources.

Title VI Implementation Plan
City of Lathrop
13 534
Appendix B

YOUR RIGHTS AGAINST DISCRIMINATION UNDER
TITLE VI OF THE CIVIL RIGHTS ACT OF 1964 AND

RELATED NON- DISCRIMINATORY AUTHORITIES
Title VI of the Civil Rights Act of 1964 provides that no person in the United States shall, on the grounds of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be subjected to discrimination under any program or activity receiving federal financial assistance.

The following additional authorities provide protection against discrimination on the basis of sex, age, disability, religion, sexual orientation, gender identity, or any other category protected by State or Federal law:

Section 162( a) of the Federal - Aid Highway Act of 1973 (Section 324, Title 23 U. S. C.) Section 504 of the Rehabilitation Act of 1973
The Age Discrimination Act of 1975 (Section 6101-107, Title 42 U. S. C.) The Civil Rights Restoration Act of 1987 ( Public Law 200-9) Executive Order 12898 ( issued February 11, 1994)
Executive Order 13166 ( issued August 16, 2000)
Any person who believes that they have been discriminated against may file a written complaint with the City of Lathrop Public Works Department, within 180 days of the alleged discrimination. Additional information and Title VI Complaint Forms can be obtained on the City of Lathrop' s website, at the following location:
www. yubacity. net/ TitleVl . Title VI Complaint Forms can also be obtained from the Public Works Department at City Hall.

To file a Title VI discrimination complaint, please use the following contact information:

City of Lathrop Public Works
390 Towne Centre Drive
Lathrop, CA 95330
209) 941- 7430
website_ pwk@ci. lathrop. ca. us
Title VI Implementation Plan
City of Lathrop
14 535
Appendix C

TITLE VI COMPLAINT FORM
Title VI of the 1964 Civil Rights Act requires that " No person in the United States shall on the grounds of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be subjected to discrimination under any program or activity receiving federal financial assistance." If you wish to submit a Title VI complaint to the City of Lathrop Public Works Department, please complete the below information and submit this form to:

City of Lathrop Public Works
390 Towne Centre Drive
Lathrop, CA 95330
209) 941- 7430
website_ pwk@ci. lathrop. ca. us
Name:

Address:

City: State: Zip Code:

CeII: Home:

Name, title, and description of person( s) who allegedly discriminated against you:

Check the box( es) for the type( s) of discrimination that was experienced:

Race
Color
National Origin
Other ( Please Describe):

Sex
Age
Disability
Religion
Sexual Orientation
Gender Identity
Date( s) that alleged event( s) took place:

Location( s) where the alleged event( s) took place:

Title VI Implementation Plan
City of Lathrop
15 536
Is the alleged discrimination still ongoing?:

In your own words, please describe the alleged discrimination, explain what happened, and who you believe is responsible:

Please list any person( s) we may contact for additional information to provide further information for your complaint:

Have you filed this complaint with any other federal agency, state agency, federal court, or state court?:

If yes, please check all that apply:

Federal Agency
State Agency
Federal Court
State Court
Please provide the name, phone number, and email of the contact persons at the agency/ court where the complaint was filed, below:

Please sign and date this form on the lines provided below. If any additional space is needed to provide information about this complaint, please attach the additional information to this form.

Signature: Date:

Title VI Implementation Plan
City of Lathrop
16 537
Appendix D
US DOT Title VI Assurances A -E

APPEND XA
During the performance of this contract, the contractor, for itself, its assignees, and successors in interest hereinafter referred to as the "contractor") agrees as follows:

1. Compliance with Regulations: The contractor ( hereinafter includes consultants) will comply with the Acts and the Regulations relative to Nondiscrimination in Federally -assisted programs of the U. S.

Department of Transportation, Federal Highway Administration, as they may be amended from time to time, which are herein incorporated by reference and made a part of this contract.

2. Non- discrimination: The contractor, with regard to the work performed by it during the contract, will not discriminate on the grounds of race, color, national origin, age, sex, or disability in the selection and retention of subcontractors, including procurements of materials and leases of equipment. The contractor will not participate directly or indirectly in the discrimination prohibited by the Acts and the Regulations, including employment practices when the contract covers any activity, project, or program set forth in Appendix B of 49 CFR Part 21.

3. Solicitation for Subcontracts, Including Procurements of Materials and Equipment: In all solicitations, either by competitive bidding, or negotiation made by the contractor for work to be performed under a subcontract, including procurements of materials, or leases of equipment, each potential subcontractor or supplier will be notified by the contractor of the contractor' sobligations under this contract and the Acts and the Regulations relative to Non- discrimination on the grounds of race, color, national origin, age, sex, or disability.

4. Information and Reports: The contractor will provide all information and reports required by the Acts, the Regulations, and directives issued pursuant thereto and will permit access to its books, records, accounts, other sources of information, and its facilities as may be determined by the Recipient or the FHWA to be pertinent to ascertain compliance with such Acts, Regulations, and instructions. Where any information required of a contractor is in the exclusive possession of another who fails or refuses to furnish the information, the contractor will so certify to the Recipient or the FHWA, as appropriate, and will set forth what efforts it has made to obtain the information.

5. Sanctions for Noncompliance: In the event of a contractor' s noncompliance with the Nondiscrimination provisions of this contract, the Recipient will impose such contract sanctions as it or the FHWA may determine to be appropriate, including, but not limited to:

1. withholding payments to the contractor under the contract until the contractor complies; and/ or

2. cancelling, terminating, or suspending a contract, in whole or in part.

6. Incorporation of Provisions: The contractor will include the provisions of paragraphs one through six in every subcontract, including procurements of materials and leases of equipment, unless exempt by the Acts, the Regulations and directives issued pursuant thereto. The contractor will take action with respect to any subcontract or procurement as the Recipient or the FHWA may direct as a means of enforcing such provisions including sanctions for noncompliance. Provided, that if the contractor becomes involved in, or threatened with litigation by a subcontractor, or supplier because of such direction, the contractor may request the Recipient to enter into any litigation to protect the interests of the Recipient. In addition, the contractor may request the United States to enter into the litigation to protect the interests of the United States.

Title VI Implementation Plan
City of Lathrop
17 538

APPENDIX B

CLAUSES FOR DEEDS TRANSFERRING UNITED STATES PROPERTY
The following clauses will be included in deeds effecting or recording the transfer of real property, structures, or improvements thereon, or granting interest therein from the United States pursuant to the provisions of Assurance 4:

NOW THEREFORE, the U. S. Department of Transportation as authorized by law and upon the condition that the California Department of Transportation will accept title to the lands and maintain the project constructed thereon in accordance with Title 23 U. S. C., the regulations for the administration of the preceding statute, and the policies and procedures prescribed by the FHWA of the U. S. Department of Transportation in accordance and in compliance with all requirements imposed by Title 49, Code of Federal Regulations, U. S. Department of Transportation, Subtitle A, Office of the Secretary, Part 21, Nondiscrimination in Federally - assisted programs of the U. S. Department of Transportation pertaining to and effectuating the provisions of Title VI of the Civil Rights Act of 1964 ( 78 Stat. 252; 42 U. S. C. § 2000d to 2000d- 4), does hereby remise, release, quitclaim and convey unto the California Department of Transportation all the right, title and interest of the U. S. Department of Transportation in and to said lands described in Exhibit A attached hereto and made a part hereof.

HABENDUM CLAUSE)
TO HAVE AND TO HOLD said lands and interests therein unto the California Department of Transportation and its successors forever, subject, however, to the covenants, conditions, restrictions and reservations herein contained as follows, which will remain in effect for the period during which the real property or structures are used for a purpose for which Federal financial assistance is extended or for another purpose involving the provision of similar services or benefits and will be binding on the California Department of Transportation, its successors and assigns.

The California Department of Transportation, in consideration of the conveyance of said lands and interest in lands, does hereby covenant and agree as a covenant running with the land for itself, its successors and assigns, that ( 1) no person will on the grounds of race, color, or national origin, be excluded from participation in, be denied the benefits of, or be otherwise subjected to discrimination with regard to any facility located wholly or in part on, over, or under such lands hereby conveyed [,] [ and]* (2) that the California Department of Transportation will use the lands and interests in lands and interest in lands so conveyed, in compliance with all requirements imposed by or pursuant to Title 49, Code of Federal Regulations, U. S. Department of Transportation, Subtitle A, Office of the Secretary, Part 21, Nondiscrimination in Federally - assisted programs of the U. S. Department of Transportation, Effectuation of Title VI of the Civil Rights Act of 1964, and as said Regulations and Acts may be amended[, and ( 3) that in the event of breach of any of the above - mentioned non- discrimination conditions, the Department will have a right to enter or re- enter said lands and facilities on said lands, and that above described land and facilities will thereon revert to and vest in and become the absolute property of the U. S. Department of Transportation and its assigns as such interest existed prior to this instruction].* Reverter clause and related language to be used only when it is determined that such a clause is necessary in order to make clear the purpose of Title VI.) Title VI Implementation Plan
City of Lathrop
18 539

APPENDIX C

CLAUSES FOR TRANSFER OF REAL PROPERTY ACQUIRED OR IMPROVED UNDER THE ACTIVITY,

FACILITY, OR PROGRAM
The following clauses will be included in deeds, licenses, leases, permits, or similar instruments entered into by the California Department of Transportation pursuant to the provisions of Assurance 7(a):

A. The ( grantee, lessee, permittee, etc. as appropriate) for himself/ herself, his/er heirs, personal representatives, successors in interest, and assigns, as a part of the consideration hereof, does hereby covenant and agree [ in the case of deeds and leases add " as a covenant running with the land"] that:

1. In the event facilities are constructed, maintained, or otherwise operated on the property described in this (deed, license, lease, permit, etc.) for a purpose for which a U. S. Department of Transportation activity, facility, or program is extended or for another purpose involving the provision of similar services or benefits, the ( grantee, licensee, lessee, permittee, etc.) will maintain and operate such facilities and services in compliance with all requirements imposed by the Acts and Regulations ( as may be amended) such that no person on the grounds of race, color, or national origin, will be excluded from participation in, denied the benefits of, or be otherwise subjected to discrimination in the use of said facilities.

B. With respect to licenses, leases, permits, etc., in the event of breach of any of the above Nondiscrimination covenants, the California Department of Transportation will have the right to terminate the lease, license, permit, etc.) and to enter, re- enter, and repossess said lands and facilities thereon, and hold the same as if the ( lease, license, permit, etc.) had never been made or issued." C. With respect to a deed, in the event of breach of any of the above Nondiscrimination covenants, the California Department of Transportation will have the right to enter or re- enter the lands and facilities thereon, and the above described lands and facilities will there upon revert to and vest in and become the absolute property of the California Department of Transportation and its assigns.* Reverter clause and related language to be used only when it is determined that such a clause is necessary to make clear the purpose of Title VI.)
Title VI Implementation Plan
City of Lathrop
19 540

APPENDIX D
CLAUSES FOR CONSTRUCTION/ USE. ACCSS TO REAL PROPERTY ACQUIRED UNDER THE

ACTIVITY, FACILITY OR PROGRAM
The following clauses will be included in deeds, licenses, permits, or similar instruments/ agreements entered into by the California Department of Transportation pursuant to the provisions of Assurance 7(b):

A. The (grantee, licensee, permittee, etc., as appropriate) for himself/ herself, his/er heirs, personal representatives, successors in interest , and assigns, as a part of the consideration hereof, does hereby covenant and agree ( in the case of deeds and leases add, "as a covenant running with the land") that ( 1) no person on the ground of race, color, or national origin, will be excluded from participation in, denied the benefits of, or be otherwise subjected to discrimination in the use of said facilities, (2) that in the construction of any improvements on, over, or under such land, and the furnishings of services thereon, no person on the ground of race, color, or national origin, will be excluded from participation in, denied the benefits or, or otherwise be subjected to discrimination, 3) that the (grantee, licensee, lessee, permittee, etc.) will use the premises in compliance with all other requirements imposed by or pursuant to the Acts and Regulations, as amended, set forth in this Assurance.

B. With respect to ( licenses, leases, permits, etc.) in the event of breach of any of the above of the above Non- discrimination covenants, the California Department of Transportation will have the right to terminate the ( license, permits, etc., as appropriate) and to enter or re- enter and repossess said land and the facilities thereon, and hold the same as if said ( license, permit, etc., as appropriate) had never been made or issued.*
C. With respect to deeds, in the event of breach of any of the above Nondiscrimination covenants, the California Department of Transportation will there upon revert to and vest in and become the absolute property of the California Department of Transportation and its assigns.

Reverter clause and related language to be used only when it is determined that such a clause is necessary to make clear the purpose of Title VI.)
Title VI Implementation Plan
City of Lathrop
20 541

APPENDIX E
During the performance of this contract, the contractor, for itself, its assignees, and successors in interest hereinafter referred to as the " contractor") agrees to comply with the following non- discrimination statutes and authorities, including, but not limited to: Pertinent Non -Discrimination Authorities:

Title VI of the Civil Rights Act of 1964 ( 42 U. S. C. § 2000d et seq., 78 stat. 252), prohibits discrimination on the basis of race, color, national origin); and 49 CFR Part 21.

The Uniform Relocation Assistance and Real Property Acquisition Policies Act of 1970, (42 U. S. C. 4601), (prohibits unfair treatment of persons displaced or whose property has been acquired because of Federal or Federal -aid programs and projects); Federal -Aid Highway Act of 1973, (23 U. S. C. § 324 et seq.), prohibits discrimination on the basis of sex;
Section 504 of the Rehabilitation Act of 1973, (29 U. S. C. § 794 et seq.), as amended, ( prohibits discrimination on the basis of disability); and 49 CR Part 27; The Age Discrimination Act of 1975, as amended, ( 42 U. S. C. § 6101 et seq.), prohibits discrimination on the basis of age);
Airport and Airway Improvement Act of 1982, (49 U. S. C. § 471, Section 47123), as amended, prohibits discrimination based on race, creed, color, national origin, or sex); The Civil Rights Restoration Act of 1987, ( PL 100- 209), (Broadened the scope, coverage and applicability of Title VI of the Civil Rights Act of 1964, The Age Discrimination Act of 1975 and Section 504 of the Rehabilitation Act of 1973, by expanding the definition of the terms " programs or activities" to include all of the programs or activities of the Federal - aid recipients, sub -recipients and contractors, whether such programs or activities are Federally funded or not); Titles II and III of the Americans with Disabilities Act, which prohibit discrimination of the basis of disability in the operation of public entities, public and private transportation systems, places of public accommodation, and certain testing entities ( 42 U. S. C. §§ 12131 — 12189) as implemented by Department of Transportation regulations 49 C. F. R. parts 37 and 38; The Federal Aviation Administration' sNon- discrimination statute ( 49 U. S. C. § 47123) ( prohibits discrimination on the basis of race, color, national origin, and sex); Executive Order 12898, Federal Actions to Address Environmental Justice in Minority Populations and Low -Income Populations, which ensures discrimination against minority populations by discouraging programs, policies, and activities with disproportionately high and adverse human health or environmental effects on minority and low- income populations; Executive Order 13166, Improving Access to Services for Persons with Limited English Proficiency, and resulting agency guidance, national origin discrimination includes discrimination because of limited English proficiency ( LEP). To ensure compliance with Title VI, you must take reasonable steps to ensure that LEP persons have meaningful access to your programs ( 70 Fed. Reg. at 74087 to 74100);
Title IX of the Education Amendments of 1972, as amended, which prohibits you from discriminating because of sex in education programs or activities ( 20 U. S. C. 1681 et seq).

Title VI Implementation Plan
City of Lathrop
21 542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563

PAGE LEFT

INTENTIONALLY
BLANK
564
ITEM 4. 12

CITY MANAGER' SREPORT
OCTOBER 13, 2025 CITY COUNCIL REGULAR MEETING
ITEM: APPROVE AGREEMENT WITH ALISTO ENGINEERING
GROUP, INC. TO PROVIDE PROFESSIONAL

ENGINEERING CONSULTING SERVICES FOR THE

MOSSDALE WASTEWATER PUMP STATION ACCESS

MODIFICATIONS AND UPGRADES PROJECT, CIP WW
26- 09
RECOMMENDATION: Adopt Resolution to Approve an Agreement with Alisto Engineering Group, Inc. to Provide
Professional Engineering Consulting Services for the
Mossdale Wastewater Pump Station Access
Modifications and Upgrades Project, CIP WW 26- 09
SUMMARY:

The Mossdale Wastewater Pump Station Access Modifications and Upgrades Project, CIP WW 26- 09 is necessary to address access and equipment deficiencies at the existing facility. On July 10, 2025, staff issued a request for proposals for professional engineering consulting services and received two proposals by August 13th, 2025. Following a thorough evaluation, Alisto Engineering Group, Inc. (Alisto) was determined to be the most qualified consultant.

Staff recommend that the Council approve a professional services agreement with Alisto in the amount of $ 94, 480. Sufficient funds have been allocated to CIP WW 26- 09 for the Fiscal Year 2025-026 budget to cover these costs.

BACKGROUND:

The Mossdale Wastewater Pump Station is in a residential neighborhood near the intersection of River Islands Parkway and McKee Boulevard. The wet well and some electrical panels are housed within a concrete masonry unit ( CMU) structure, while additional electrical cabinets are situated adjacent to the building. The station also features a steel -framed roof with metal roof panels.

The existing roll -up door and access hatch configuration create significant maintenance challenges, as Vac -Con trucks cannot access the wet well hatch. As a result, the wet well must be cleaned manually, requiring excessive time and labor.

In addition, the station' s electrical equipment, cabinets, pumps, hardware and software are approximately 20 years old and are no longer supported by their manufacturers, making replacement necessary.
565
CITY MANAGER' S REPORT PAGE 2
OCTOBER 13, 2025 CITY COUNCIL REGULAR MEETING
APPROVE AGREEMENT WITH ALISTO ENGINEERING GROUP, INC. TO

PROVIDE PROFESSIONAL ENGINEERING CONSULTING SERVICES FOR THE

MOSSDALE WASTEWATER PUMP STATION ACCESS MODIFICATIONS AND UPGRADES PROJECT, CIP WW 26- 09
Maintaining the pump station under these conditions is inefficient, poses safety risks to personnel, and accelerates equipment wear. Furthermore, in the event of equipment failure, the limited storage capacity ( approximately one day) could lead to service disruptions, presenting a serious public safety concern.

RECOMMENDATION:

The Mossdale Wastewater Pump Station Access Modifications and Upgrades Project, Capital Improvement Project ( CIP) WW 26- 09 is necessary to address access limitations and aging equipment deficiencies at the existing facility.

On July 10, 2025, staff issued a Request for Proposals ( RFP) for professional engineering consulting services to conduct a condition assessment and provide design services for the project. Two proposals were received by the August 13th, 2025 deadline. After evaluating and ranking the proposals, staff determined Alisto Engineering Group, Inc. (Alisto) is the most qualified consultant.

Staff recommend that Council approve a professional services agreement with Alisto to provide professional engineering design services for the project.

FISCAL IMPACT:

The $ 94, 480 cost of the agreement with Alisto will be funded through the Mossdale Wastewater Pump Station Access Modifications and Upgrades Project, CIP WW 26-

09. Sufficient funds are allocated in the Fiscal Year 2025-026 budget to cover this expense.

ATTACHMENTS:

A. Resolution to Approve an Agreement with Alisto Engineering Group, Inc. to Provide Professional Engineering Consulting Services for the Mossdale Wastewater Pump Station Access Modifications and Upgrades Project, CIP WW 26- 09
B. Agreement with Alisto Engineering Group, Inc. to Provide Professional Engineering Consulting Services for the Mossdale Wastewater Pump Station Access Modifications and Upgrades Project, CIP WW 26- 09 566
CITY MANAGER' SREPORT PAGE 3
OCTOBER 13, 2025 CITY COUNCIL REGULAR MEETING
APPROVE AGREEMENT WITH ALISTO ENGINEERING GROUP, INC. TO

PROVIDE PROFESSIONAL ENGINEERING CONSULTING SERVICES FOR THE

MOSSDALE WASTEWATER PUMP STATION ACCESS MODIFICATIONS AND UPGRADES, CIP WW 26- 09
APPROVALS:
q/ 411 -0i -c"
Greg Ct6son Date
Senior Civil Engineer
BradOfaylor
City Engineer
Cari Ja
Financ Di ector
Date
9is1, 2o.,,-
Date
1 - 11 - Zees
Michael King Date
Assistant City Manager
Salvador Navarrete Date
City Attorney
Stephen J. Salvatore Date
City Manager
567
RESOLUTION NO. 25 -

A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF LATHROP TO APPROVE AN AGREEMENT WITH ALISTO ENGINEERING GROUP, INC. TO

PROVIDE PROFESSIONAL ENGINEERING CONSULTING SERVICES FOR THE

MOSSDALE WASTEWATER PUMP STATION ACCESS MODIFICATIONS AND UPGRADES PROJECT, CIP WW 26- 09
WHEREAS, the Mossdale Wastewater Pump Station Access Modifications and Upgrades, Capital Improvement Project ( CIP) WW 26- 09 is needed to address existing access and equipment deficiencies at the existing facility; and WHEREAS, the existing roll -up door and access hatch configuration create significant maintenance challenges, as Vac -Con trucks cannot access the wet well hatch. As a result, the wet well must be cleaned manually, requiring excessive time and labor; and
WHEREAS, in addition, the station' s electrical equipment, cabinets, pumps, hardware and software are approximately 20 years old and are no longer supported by their manufacturers, making replacement necessary; and WHEREAS, on July 10, 2025, staff issued a Request for Proposals ( RFP) for professional engineering consulting services to conduct a condition assessment and provide design services for the project and received two proposals by August 13th, 2025. Following a thorough evaluation, Alisto Engineering Group, Inc. (Alisto) was determined to be the most qualified consultant; and
WHEREAS, staff recommend that Council approve a professional services agreement with Alisto Engineering Group, Inc. in the amount of $ 94, 480 to provide engineering services to design the project; and
WHEREAS, the $ 94, 480 cost of the agreement with Alisto will be funded through the Mossdale Wastewater Pump Station Access Modifications and Upgrades Project, CIP WW 26- 09. Sufficient funds are allocated in the Fiscal Year 2025-026 budget to cover this expense.

NOW THEREFORE, BE IT RESOLVED, the City Council of the City of Lathrop does hereby approve an agreement a with Alisto Engineering Group, Inc. in the amount of $ 94, 480 to provide professional engineering design services for the Mossdale Wastewater Pump Station Access Modification and Upgrades, CIP WW 26-

09. 568
The foregoing resolution was passed and adopted this 13th day of October 2025, by the following vote of the City Council, to wit:

AYES:

NOES:

ABSENT:

ABSTAIN:

Paul Akinjo, Mayor
ATTEST: APPROVED AS TO FORM:

Teresa Vargas, City Clerk Salvador Navarrete, City Attorney 569
Attachment B

CITY OF LATHROP

AGREEMENT FOR PROFESSIONAL SERVICES WITH ALISTO ENGINEERING GROUP, INC.

TO PROVIDE PROFESSIONAL ENGINEERING CONSULTING SERVICES FOR THE

MOSSDALE WASTEWATER PUMP STATION ACCESS MODIFICATIONS AND UPGRADES, CIP WW 26- 09
THIS AGREEMENT, dated for convenience this 13th day of October, 2025, is by and between Alisto Engineering Group, Inc. ("CONSULTANT") and the City of Lathrop, a California municipal corporation (" CITY");
RECITALS:

WHEREAS, CONSULTANT is specially trained, experienced, and competent to perform Professional Engineering Consulting Services, which are required by this agreement; and WHEREAS, CITY selected the CONSULTANT pursuant to said qualifications; and WHEREAS, CONSULTANT is willing to render such Professional Engineering Consulting Services, as hereinafter defined, on the following terms and conditions; NOW, THEREFORE, CONSULTANT and the CITY agree as follows:

AGREEMENT
1) Scope of Service
CONSULTANT agrees to perform Professional Services in accordance with the scope of work and fee proposal provided by CONSULTANT, attached hereto as Exhibit " A" and incorporated herein by reference. CONSULTANT represents it is prepared to and can diligently perform these services in accordance with the upmost standards of its profession and to CITY' Ssatisfaction. The fee proposal shall include all reimbursable costs required for the performance of the Scope of Services. Payment of additional reimbursable costs considered to be over and above those inherent in the original Scope of Services shall be approved of in advance and in writing, by the CITY.
2) Compensation
CITY hereby agrees to pay CONSULTANT a sum not to exceed $ 94, 480 for the Professional Engineering Consulting Services set forth in Exhibit "A". CONSULTANT shall be paid any uncontested sum due and payable within thirty ( 30) days of receipt of billings containing all information pursuant to Paragraph 5 below. Compensation for any task must be equal to or less than the percentage of task complete. In no event shall CONSULTANT be entitled to compensation for work not included in Exhibit " A", unless a written change order or authorization describing the extra work and payment terms has been executed by CITY' s authorized representative prior to the commencement of the work. Payment is made based on a time and materials basis. 570
CITY OF LATHROP - ALISTO ENGINEERING GROUP, INC.

PROFESSIONAL ENGINEERING CONSULTING SERVICES FOR THE MOSSDALE WASTEWATER PUMP STATION ACCESS MODIFICATIONS AND UPGRADES, CIP WW 26- 09 3) Effective Date and Term
The effective date of this Agreement is October 13, 2025, and it shall terminate no later than June 30, 2027.
4) Independent Contractor Status
It is expressly understood and agreed by both parties that CONSULTANT, while engaged in carrying out and complying with any of the terms and conditions of this Agreement, is an independent contractor and not an employee of the CITY. As an independent contractor, CONSULTANT is responsible for controlling the means and methods to complete the scope of work described in Exhibit "A" to City' ssatisfaction. CONSULTANT expressly warrants not to represent, at any time or in any manner, that CONSULTANT is an employee of the CITY.
5) Billings
CONSULTANT shall submit invoices for completed work on a monthly basis, or as otherwise agreed, providing without limitation, details as to amount of hours, individual performing said work, hourly rate, and indicating to what aspect of the Scope of Services said work is attributable. CONSULTANT' Sbills shall include a list of all tasks, a total amount due, the amounts previously billed, and the net amount due on the invoice. Except as specifically authorized by CITY, CONSULTANT shall not bill CITY for duplicate services performed by more than one person. In no event shall CONSULTANT submit any billing for an amount in excess of the rates or the maximum amount of compensation provided in section ( 2) for either task or for the entire Agreement, unless modified by a properly executed change order.
6) Advice and Status Reporting
CONSULTANT shall provide the CITY with timely reports, orally or in writing, of all significant developments arising during performance of its services hereunder, and shall furnish to CITY such information as is necessary to enable CITY to monitor the performance of this Agreement.

CONSULTANT shall submit to CITY such reports, diagrams, drawings and other work products developed pursuant to the Scope of Services.
7) Assignment of Personnel
CONSULTANT acknowledges that the CITY has relied on CONSULTANT' scapabilities and on the qualifications of CONSULTANT' sprincipals and staff as identified in its proposal to CITY. The services shall be performed by, or under the direct supervision, of CONSULTANT' sAuthorized Representative: Al Sevilla, PE. CITY shall be notified by CONSULTANT of any change of its Authorized Representative, and CITY is granted the right of approval of all original, additional, and replacement personnel at CITY' s sole discretion,
project staff
and
prior
shall
to any
be
change.
notified by CONSULTANT of any changes of CONSULTANT' s
CONSULTANT shall assign only competent personnel to perform services pursuant to this Agreement. If CITY asks CONSULTANT to remove a person assigned to the work called

Page 2 of 11 ends

Lathrop City CouncilOctober 13, 2025

Lathrop City Council
October 13, 2025