CITY OF EL CENTRO SEWER LIFT STATION CONDITION ASSESSMENT TECHNICAL MEMORANDUM 16707 174 OCTOBER 2025
• Perform power system study that includes short circuit analysis, coordination, and arc flash analysis and install Arc flash stickers on all electrical equipment at each lift station • Relocate all electrical and controls equipment outside of hazardous envelopes • Install sealing fittings, or seal-offs, on all conduits that exit wet wells and that exit hazardous envelopes at each site
- This is a safety hazard due to the possibility of H2S gases leaking into, and accumulating inside of, electrical panels or enclosures that have equipment that is not spark-proof or explosion-proof • Relocate conduit penetrations for float switches and level sensors outside of equipment enclosures that have electrical and controls equipment in them.
- This is a safety hazard due to the possibility of H2S gases leaking into, and accumulating inside of, electrical panels or enclosures that have equipment that is not spark-proof or explosion-proof - An alternate solution is to move all electrical and controls equipment out of pump enclosure and out of hazardous envelope
• Install an on-site water connection for all sites to provide a water supply for site wash-down • Install bypass connections for all lift station sites that do not currently have one These improvements will enhance safety and reliability at each lift station.
4.3 Lift Station CIP Projects
In addition to the City’s lift station ongoing improvements, scheduled improvements, and operational changes described in Section 4.1, Dudek’s evaluation and assessment identified additional recommendations aimed at further enhancing the performance, reliability, operability, and longevity of the City’s lift stations. The recommendations identified throughout Section 3 were grouped into capital improvement projects and aim to address observed deficiencies, operational nuisances, and potential safety or security risks that were identified during the field inspections and through conversations with the City’s operation staff for each site. A general description and prioritization ranking of the Lift Station CIP projects is presented in Table 64. The prioritization of the Lift Station CIP projects is discussed in further detail in Section 4.3.1.
CITY OF EL CENTRO SEWER LIFT STATION CONDITION ASSESSMENT TECHNICAL MEMORANDUM 16707 175 OCTOBER 2025
Table 64. Recommended Lift Station CIP Projects
Project No. Project Name
Prioritization
Rank
Description1
LSP.01
Structures, Hatches /
Doors, and Bypass
Connection Program –
Phase 1
1 Phase 1 of a replacement and rehabilitation program focused on the replacement or rehabilitation of high priority structures, hatches/doors, and bypass connections.
LSP.02
Arc Flash / Short Circuit
Study 2
A program focused on the completion of power system studies and updating Arc Flash labeling.
LSP.03
Testing and Studies
Program 3
A program focused on enhancing the evaluation of seismic and electrical resiliency at Main LS, Lift Station No. 3, and Alder Canal - Villa Ave LS.
LSP.04
Instrumentation and
Control Program - Phase 1 4
Phase 1 of a program focused on the replacement and upgrade of critical electrical and controls equipment.
LSP.05
Force Main Program -
Phase 1 5
Phase 1 of a program focused on replacing critical force mains to address existing operational challenges and capacity limitations. Phase 1 targets deficiencies at Lift Station No. 3.
LSP.06
Power and Generator
Program 6
A program focused on improving reliability of lift station power systems through the installation of permanent backup generators or portable generator transfer switch.
LSP.07
Structures, Hatches /
Doors and Bypass
Connection Program -
Phase 2
7 Phase 2 of a replacement and rehabilitation program focused on the replacement or rehabilitation of moderate priority structures, hatches/doors, and bypass connections.
LSP.08
Instrumentation and
Control Program - Phase 2 8
Phase 2 of a program focused on the replacement and upgrade of critical electrical and controls equipment.
LSP.09
Pumps, Piping, Supports,
and HVAC Program 9 A program focused on critical mechanical and ventilation improvements.
LSP.10 Main Lift Station
Rehabilitation Project 10 A project focused on the Main LS assets that require rehabilitation or replacement and are not included in the preceding Lift Station CIP projects.
LSP.11 East Side Lift Station
Rehabilitation Project 11 A project focused on the East Side LS assets that require rehabilitation or replacement and are not included in the preceding Lift Station CIP projects.
LSP.12 Buena Vista Lift Station
Rehabilitation Project 12 A project focused on the Buena Vista LS assets that require rehabilitation or replacement and are not included in the preceding Lift Station CIP projects.
LSP.13 Legacy Lift Station
Decommissioning Project 13 A project focused on the decommission of Legacy LS, in accordance with the new Southern Lift Station being brought online.
CITY OF EL CENTRO SEWER LIFT STATION CONDITION ASSESSMENT TECHNICAL MEMORANDUM 16707 176 OCTOBER 2025
Table 64. Recommended Lift Station CIP Projects
Project No. Project Name
Prioritization
Rank
Description1
LSP.14 4th & Wake Lift Station
Decommissioning Project 14 A project focused on the decommission of 4th & Wake LS, in accordance with the new Southern Lift Station being brought online.
LSP.15 Force Main Program -
Phase 2 15
Phase 2 of a program focused on replacing critical force mains to address existing operational challenges and capacity limitations. Phase 1 targets deficiencies at Alder Canal - Villa Ave LS.
LSP.16 Gios Lift Station
Rehabilitation Project 16 A project focused on the Gios LS assets that require rehabilitation or replacement and are not included in the preceding Lift Station CIP projects.
LSP.17 Lift Station No. 3
Rehabilitation Project 17 A project focused on the Lift Station No. 3 assets that require rehabilitation or replacement and are not included in the preceding Lift Station CIP projects.
LSP.18 8th & Wake Lift Station
Rehabilitation Project 18 A project focused on the 8th & Wake LS assets that require rehabilitation or replacement and are not included in the preceding Lift Station CIP projects.
LSP.19
Alder Canal - Villa Ave Lift
Station Rehabilitation
Project
19 A project focused on the Alder Canal - Villa Ave assets that require rehabilitation or replacement and are not included in the preceding Lift Station CIP projects.
LSP.20 3rd & Ross Lift Station
Rehabilitation Project 20 A project focused on the 3rd & Ross LS assets that require rehabilitation or replacement and are not included in the preceding Lift Station CIP projects.
1. For more detailed Lift Station CIP project descriptions, refer to Attachment A: Lift Station CIP Project Cutsheets.
CITY OF EL CENTRO SEWER LIFT STATION CONDITION ASSESSMENT TECHNICAL MEMORANDUM 16707 177 OCTOBER 2025
4.3.1 Project Prioritization
Project prioritization scores were developed at the
asset, asset discipline, and project level. Each asset
was evaluated for criticality, risk of injury, condition, and remaining useful life. These ratings were weighted
by relative importance and combined to generate a
total asset score.
For each project, asset discipline scores (mechanical,
structural, site civil, and electrical/instrumentation) were calculated by averaging the total asset scores of
all assets within that discipline. The discipline scores were then averaged to produce a total project score,
which was further weighted by project criticality. The
resulting weighted project prioritization score
established the relative priority of each project. The
Lift Station CIP project prioritization scoring
methodology is outlined on Figure 219. The results of
the prioritization ranking are shown in Table 64.
The calculated prioritization scores were used to
identify three distinct tiers and split the projects into near-term, mid-term, and long-term priority timelines.
The priority timeline assignments also considered the
City’s input on available resources (e.g., funds, staff) and the City’s risk tolerance.
It is important to note that maintenance
improvements were separated from the Lift Station
CIP, as they are routine in nature and expected to be
addressed by the City’s Operations and Maintenance
(O&M) staff rather than through capital projects. The
following subsection describes the near-term, midterm, and long-term priority timelines in more detail.
4.3.1.1 Maintenance Improvements
Maintenance projects consist of improvements that can be carried out by the City’s operations and maintenance staff. These improvements tend to include proactive actions intended to extend the useful life of a lift station and its component asset. Maintenance improvements can also include reactive actions which mitigate an existing issue or violation. Maintenance improvements have not been included in a Lift Station CIP project due to the nature of the action.
Figure 219. Lift Station CIP Project
Prioritization Methodology
CITY OF EL CENTRO SEWER LIFT STATION CONDITION ASSESSMENT TECHNICAL MEMORANDUM 16707 178 OCTOBER 2025
4.3.1.2 Near-Term Projects
Near-term Lift Station CIP projects are high priority projects that should be completed in the next two to five years, or FY 2027 to FY 2030. The majority of appurtenances within these projects are in poor condition. Based on the lift station condition assessment and prioritization summarized in Table 64, the following prioritization of the near-term projects was developed:
1. Structures, Hatches / Doors, and Bypass Connection Program – Phase 1
2. Arc Flash / Short Circuit Study
3. Testing and Studies Program
4. Instrumentation and Control Program - Phase 1
5. Force Main Program - Phase 1
6. Power and Generator Program
4.3.1.3 Mid-Term Projects
Mid-term Lift Station CIP projects are moderate priority projects that should be completed in the next six to nine years, or FY 2031 to FY 2034. The majority of appurtenances within these projects are in fair condition. Based on the lift station condition assessment and prioritization summarized in Table 64, the following prioritization of the mid-term projects was developed:
1. Structures, Hatches / Doors and Bypass Connection Program - Phase 2
2. Instrumentation and Control Program - Phase 2
3. Pumps, Piping, Supports, and HVAC Program
4. Main Lift Station Rehabilitation Project
5. East Side Lift Station Rehabilitation Project
6. Buena Vista Lift Station Rehabilitation Project
7. Legacy Lift Station Decommissioning Project
8. 4th & Wake Lift Station Decommissioning Project
9. Force Main Program - Phase 2
CITY OF EL CENTRO SEWER LIFT STATION CONDITION ASSESSMENT TECHNICAL MEMORANDUM 16707 179 OCTOBER 2025
4.3.1.4 Long-Term Projects
Long-term Lift Station CIP projects are low priority projects or improvements that should be completed in the next ten years to twenty years, or FY 2035-46. The majority of appurtenances within these projects are in either fair or good condition. Based on the lift station condition assessment and prioritization summarized in Table 64, the following prioritization of the long-term projects was developed:
1. Gios Lift Station Rehabilitation Project
2. Lift Station No. 3 Rehabilitation Project
3. 8th & Wake Lift Station Rehabilitation Project
4. Alder Canal - Villa Ave Lift Station Rehabilitation Project
5. 3rd & Ross Lift Station Rehabilitation Project
4.3.2 Project Cost Estimation
As part of this condition assessment, preliminary cost estimates were prepared to help the City plan for the Lift Station CIP projects. The estimates are planning-level (Class 4–5) and are intended to provide order-of-magnitude costs that can be carried forward into the Lift Station CIP. Numbers were developed using a mix of recent bid results, unit cost information from similar work in the region, vendor budget quotes, and engineering judgment.
Each Lift Station CIP project cost estimate includes:
• Construction Cost – Major equipment replacement (e.g., pumps, generators, control panels), wet well and structural rehabilitation, mechanical appurtenances, and site civil/electrical work. • Soft Costs – Engineering, construction management and administrative services were estimated at 15 to 40 percent of construction costs.
• Contingency – Applied at 40 percent to account for uncertainties typical of preliminary planning-level estimates.
The level of soft costs applied depends on the complexity of the project and the amount of design and construction oversight required. Projects that involve significant design effort or carry higher uncertainty in construction were assigned the highest soft cost allowance at 40 percent of construction costs (Soft Cost Class C). Simpler projects were assigned lower soft cost allowance (i.e., Soft Cost Classes A, B, and D). A summary of the soft cost markups used for the Lift Station CIP projects is provided in Table 65.
All costs were calculated in 2025 dollars and were escalated annually to the project midpoint using an assumed inflation rate. The Lift Station CIP project cost distribution is discussed in more detail in Section 4.3.3.
CITY OF EL CENTRO SEWER LIFT STATION CONDITION ASSESSMENT TECHNICAL MEMORANDUM 16707 180 OCTOBER 2025
Table 65. Lift Station CIP Projects Soft Cost Markup as Percent of Construction Costs Markup Category
Soft Cost Class
A B C D
Engineering 8% 10% 15% 5%
Construction Management &
Engineering Services during
Construction
15% 18% 20% 5%
Administration 2% 3% 5% 5%
Total 25% 31% 40% 15%
4.3.3 Project Cost Distribution
Lift Station CIP project costs were distributed according to the priorities discussed above and are displayed on Figure 220. Refer to Section 4.3 for Lift Station CIP project prioritization timelines and definitions. Project costs were spread over a two-year period. Approximately 15 percent of the total project cost was assigned to the first year to account for engineering and design and the remaining balance was allocated to the second year for construction.
All costs were escalated to the project midpoint from 2025 using an assumed annual inflation rate of 3 percent.
Over 90 percent of the total Lift Station CIP project costs are included within the near-term and mid-term timeframes due to the investment required to address critical deficiencies. The spike on FY 2034 is due to the high costs associated with LSP.15 (Force Main Program – Phase 2), which accounts for approximately on third of the total Lift Station CIP cost. Costs for individual Lift Station CIP projects are summarized in Section 4.3.4.
CITY OF EL CENTRO SEWER LIFT STATION CONDITION ASSESSMENT TECHNICAL MEMORANDUM 16707 181 OCTOBER 2025
Figure 220: Lift Station CIP Total Project Cost Distribution
4.3.4 Summary of Projects
The Lift Station CIP includes 20 projects that span between FY 2027 to FY 2038 and totals $33.6M, with individual projects ranging from approximately $0.1M to $10.8M. Cutsheets for each Lift Station CIP project are provided in Attachment A and a summary of the Lift Station CIP Projects is provided in Table 66.
LSP.01
Structures, Hatches / Doors and Bypass Connection Program - Phase 1 NT 5,225,000 $
$ 764,000 $ 4,459,000 LSP.02 Arc Flash / Short Circuit Study Program NT 225,000 $ $ 33,000 $ 195,000 LSP.03 Testing and Studies Program NT 225,000 $ $ 34,000 $ 197,000LSP.04 Instrumentation and Control Program - Phase 1 NT 2,025,000 $ $ 297,000 $ 1,732,000 LSP.05 Force Main Program - Phase 1 NT 1,550,000 $ $ 226,000 $ 1,317,000 LSP.06 Power and Generator Program NT 1,150,000 $ $ 168,000 $ 983,000LSP.07 Structures, Hatches / Doors and Bypass Connection Program - Phase 2 MT 2,450,000 $
$ 358,000 $ 2,089,000 LSP.08 Instrumentation and Control Program - Phase 2 MT 1,725,000 $ $ 253,000 $ 1,476,000 LSP.09 Pumps, Piping, Supports, and HVAC Program MT 1,100,000 $ $ 160,000 $ 931,000 LSP.10 Main Lift Station Rehabilitation Project MT 2,025,000 $ $ 295,000 $ 1,724,000 LSP.11 East Side Lift Station Rehabilitation Project MT 325,000 $ $ 48,000 $ 279,000LSP.12 Buena Vista Lift Station Rehabilitation Project MT 300,000 $ $ 44,000 $ 259,000LSP.13 Legacy Lift Station Decommissioning Project MT 875,000 $ $ 129,000 $ 750,000LSP.14 4th & Wake Lift Station Decommissioning Project MT 900,000 $ $ 132,000 $ 773,000LSP.15 Force Main Program - Phase 2 MT 10,800,000 $ $ 1,578,000 $ 9,210,000 LSP.16 Gios Lift Station Rehabilitation Project LT 50,000 $ $ 6,000 $ 34,000LSP.17 Lift Station No. 3 Rehabilitation Project LT 1,450,000 $ $ 213,000 $ 1,242,000 LSP.18 8th & Wake Lift Station Rehabilitation Project LT 350,000 $ $ 50,000 $ 294,000LSP.19 Alder Canal - Villa Ave Lift Station Rehabilitation Project LT 750,000 $ $ 111,000 $ 650,000LSP.20 3rd & Ross Lift Station Rehabilitation Project LT 75,000 $ $ 10,000 $ 59,000 $ 33,575,000 $ - $ 764,000 $ 4,823,000 $ 2,518,000 $ 2,658,000 $ 2,502,000 $ 2,923,000 $ 4,722,000 $ 9,983,000 $ 219,000 $ 1,326,000 $ 415,000 $ 709,000 Priority FY 2026
Total
Table 66. Lift Station CIP Project List
Project
No. Project Name
Total Project Cost
(Rounded) FY 2027 FY 2028 FY 2030 FY 2031 FY 2032 FY 2033 FY 2034 Total Project Cost
FY 2029 FY 2035 FY 2036 FY 2037 FY 2038
16707
OCTOBER 2025
CITY OF EL CENTRO SEWER LIFT STATION CONDITION ASSESSMENT TECHNICAL MEMORANDUM 16707
OCTOBER 2025
Attachment A
Lift Station Capital Improvement Program Project
Cutsheets
Project No: LSP.01
Project Name:
Description:
Priority: Near-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade X
Engineering Study
Expansion
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'B'
Engineering 10 % of capital costs
CM & ESDC 18 % of capital costs
Administration 3 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2027
Project Duration (Years): 2
1 of 20
Design-Bid-Build
Comments:
$ 883,000
$ 1,492,000
$ 5,223,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ -
$ 1,469,000
$ -
$ 313,000
$ 1,066,000
$ 2,848,000
$ 285,000
$ 513,000
$ 85,000
Failure Modes & Consequences
Structures, Hatches / Doors and Bypass Connection Program - Phase 1 This program will address near term rehabilitation and replacement of structural components at lift stations to improve safety, reliability, and long-term performance. Improvements include rehabilitation of wet wells, access hatches and doors, replacement of wet well piping and pipe supports, rehabilitation of wet well liners, replacement of access stairs, replacement of wet well access covers, and wall penetration patching and related structural improvements. The specific scope will vary by facility based on condition assessments, but implementation of this program will extend service life of key structures, improve maintainability, and ensure compliance with safety standards. Additionally, this program involves installing permanent bypass pumping connections at all lift stations that currently lack this critical feature. The bypass assemblies will provide quick and reliable access points for temporary pumps during planned maintenance or emergency events, minimizing the risk of sanitary sewer overflows and service disruptions.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
East Side LS, Alder Canal - Villa Ave LS, Countryside LS, Legacy LS, Main LS, Orange LS, 4th & Wake LS, 8th & Wake LS, 3rd & Ross LS Gios LS, Heil & Dogwood LS
Project No: LSP.02
Project Name:
Description:
Priority: Near-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement
Facility/Equip Upgrade X
Engineering Study X
Expansion X
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'C'
Engineering 15 % of capital costs
CM & ESDC 20 % of capital costs
Administration 5 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2028
Project Duration (Years): 2
2 of 20
Design-Bid-Build
Comments:
$ 46,000
$ 66,000
$ 228,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ 116,000
$ -
$ -
$ -
$ -
$ 116,000
$ 17,000
$ 23,000
$ 6,000
Failure Modes & Consequences
Arc Flash / Short Circuit Study Program
This program will improve electrical safety at lift stations through the completion of power system studies and the application of updated arc flash labeling. The work will include short circuit and coordination analyses to confirm system protection settings, along with installation of arc flash hazard warning stickers at eight lift stations. Implementation of this program will enhance worker safety, ensure compliance with electrical safety standards, and reduce risks associated with maintenance and emergency response activities.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
Main LS, Lift Station No. 3, Countryside LS, Legacy LS, Alder Canal - Villa Ave LS, 3rd & Ross LS, 4th & Wake LS, Gios LS
Project No: LSP.03
Project Name:
Description:
Priority: Near-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement
Facility/Equip Upgrade X
Engineering Study X
Expansion X
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'C'
Engineering 15 % of capital costs
CM & ESDC 20 % of capital costs
Administration 5 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2028
Project Duration (Years): 2
3 of 20
Design-Bid-Build
Comments:
$ 48,000
$ 65,000
$ 231,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ 92,000
$ -
$ -
$ -
$ 26,000
$ 118,000
$ 18,000
$ 24,000
$ 6,000
Failure Modes & Consequences
Testing and Studies Program
This program will complete specialized evaluations and third-party testing to improve safety and reliability of lift station facilities. Planned work includes a dry well seismic evaluation at one facility to assess structural resilience and independent testing of motor control centers (MCCs) and breakers at three facilities to verify electrical safety and performance. Implementation of this program will provide critical data to guide future improvements, reduce operational risks, and ensure compliance with applicable safety and reliability standards.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
Main LS, Lift Station No. 3, Alder Canal - Villa Ave LS
Project No: LSP.04
Project Name:
Description:
Priority: Near-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade X
Engineering Study
Expansion
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'B'
Engineering 10 % of capital costs
CM & ESDC 18 % of capital costs
Administration 3 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2028
Project Duration (Years): 2
4 of 20
Design-Bid-Build
Comments:
$ 343,000
$ 580,000
$ 2,029,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ 680,000
$ 426,000
$ -
$ -
$ -
$ 1,106,000
$ 111,000
$ 199,000
$ 33,000
Failure Modes & Consequences
Instrumentation and Control Program - Phase 1
This program will replace and upgrade critical electrical and control systems at lift stations, including programmable logic controllers (PLCs), motor control centers (MCCs), automatic transfer switches (ATSs), variable frequency drives (VFDs), electrical panels, conduits, site lighting, instrumentation, and control panels. The specific improvements will vary by facility based on existing conditions and operational needs, but will generally focus on standardizing equipment, improving reliability, and extending service life. Implementation of this program will enhance operational efficiency, expand remote monitoring and control capabilities, and ensure compliance with current electrical and safety standards across the collection system.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
4th & Wake LS, Main LS, Gios LS
Project No: LSP.05
Project Name:
Description:
Priority: Near-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade X
Engineering Study X
Expansion
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'B'
Engineering 10 % of capital costs
CM & ESDC 18 % of capital costs
Administration 3 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2029
Project Duration (Years): 2
5 of 20
Design-Bid-Build
Comments:
$ 260,000
$ 442,000
$ 1,543,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ -
$ 173,000
$ -
$ 668,000
$ -
$ 841,000
$ 84,000
$ 151,000
$ 25,000
Failure Modes & Consequences
Force Main Program - Phase 1
This program will replace downstream force main of Lift Station No. 3 to address existing operational challenges and capacity limitations. The work will include installation of new force mains designed to accommodate current and projected flows, along with all associated bypass pumping required to maintain service during construction. Implementation of this program will resolve hydraulic constraints, improve system reliability, and ensure the collection system can continue to operate effectively under future demand conditions.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
Lift Station No. 3
Project No: LSP.06
Project Name:
Description:
Priority: Near-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X X
Facility/Equip Upgrade X X
Engineering Study X
Expansion X
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'B'
Engineering 10 % of capital costs
CM & ESDC 18 % of capital costs
Administration 3 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2029
Project Duration (Years): 2
6 of 20
Design-Bid-Build
Comments:
$ 195,000
$ 328,000
$ 1,151,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ 177,000
$ 451,000
$ -
$ -
$ -
$ 628,000
$ 63,000
$ 113,000
$ 19,000
Failure Modes & Consequences
Power and Generator Program
This program will improve the reliability of lift station power systems through installation of permanent backup generators and portable generator connectors with transfer switches. Additional improvements include replacement of corroded generator piping, replacement of utility power poles, and replacement of main breakers. The specific scope will vary by facility based on condition assessments, but implementation of this program will enhance system resiliency, reduce the risk of service interruptions, and ensure compliance with electrical and safety standards.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
Legacy LS, Main LS, 3rd & Ross LS, Alder Canal - Villa Ave LS, Gios LS
Project No: LSP.07
Project Name:
Description:
Priority: Mid-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade X
Engineering Study
Expansion
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'B'
Engineering 10 % of capital costs
CM & ESDC 18 % of capital costs
Administration 3 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2030
Project Duration (Years): 2
7 of 20
Failure Modes & Consequences
Structures, Hatches / Doors and Bypass Connection Program - Phase 2 This program will address mid term rehabilitation and replacement of structural components at lift stations to improve safety, reliability, and long-term performance. Improvements include rehabilitation of wet wells, access hatches and doors, replacement of wet well piping and pipe supports, rehabilitation of wet well liners, replacement of access stairs, replacement of wet well access covers, and wall penetration patching and related structural improvements. The specific scope will vary by facility based on condition assessments, but implementation of this program will extend service life of key structures, improve maintainability, and ensure compliance with safety standards. Additionally, this program involves installing permanent bypass pumping connections at all lift stations that currently lack this critical feature. The bypass assemblies will provide quick and reliable access points for temporary pumps during planned maintenance or emergency events, minimizing the risk of sanitary sewer overflows and service disruptions.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
8th & Wake LS, 3rd & Ross LS, Heil & Dogwood LS, Lift Station No. 3, Alder Canal - Villa Ave LS Project Cost:
$ -
$ 594,000
$ -
$ 119,000
$ 621,000
$ 1,334,000
$ 133,000
$ 240,000
$ 40,000
$ 413,000
$ 700,000
$ 2,447,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Design-Bid-Build
Comments:
Project No: LSP.08
Project Name:
Description:
Priority: Mid-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade X
Engineering Study
Expansion
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'B'
Engineering 10 % of capital costs
CM & ESDC 18 % of capital costs
Administration 3 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2031
Project Duration (Years): 2
8 of 20
Design-Bid-Build
Comments:
$ 292,000
$ 494,000
$ 1,729,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ 318,000
$ 625,000
$ -
$ -
$ -
$ 943,000
$ 94,000
$ 170,000
$ 28,000
Failure Modes & Consequences
Instrumentation and Control Program - Phase 2
This program will replace and upgrade critical electrical and control systems at lift stations, including programmable logic controllers (PLCs), motor control centers (MCCs), automatic transfer switches (ATSs), variable frequency drives (VFDs), electrical panels, conduits, site lighting, instrumentation, and control panels. The specific improvements will vary by facility based on existing conditions and operational needs, but will generally focus on standardizing equipment, improving reliability, and extending service life. Implementation of this program will enhance operational efficiency, expand remote monitoring and control capabilities, and ensure compliance with current electrical and safety standards across the collection system.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
Lift Station No. 3, Alder Canal - Villa Ave LS, 3rd & Ross LS, Gios LS
Project No: LSP.09
Project Name:
Description:
Priority: Mid-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade X
Engineering Study
Expansion X
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'B'
Engineering 10 % of capital costs
CM & ESDC 18 % of capital costs
Administration 3 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2031
Project Duration (Years): 2
9 of 20
Design-Bid-Build
Comments:
$ 185,000
$ 311,000
$ 1,091,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ -
$ 514,000
$ -
$ 81,000
$ -
$ 595,000
$ 60,000
$ 107,000
$ 18,000
Failure Modes & Consequences
Pumps, Piping, Supports, and HVAC Program
This program will address mechanical and ventilation improvements at lift stations to enhance reliability, safety, and operability. Improvements include installation of emergency eye wash stations, replacement of force mains within wet wells, replacement of sump pumps and associated discharge piping, repair of forced air ventilation systems, replacement of pump bases, installation of chemical injection ports, replacement of suction piping in wet wells, and installation of discharge flow meters. The specific scope will vary by facility based on condition and operational needs, but implementation of this program will improve worker safety, extend equipment life, and ensure reliable system performance.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
Countryside LS, Lift Station No. 3, Alder Canal - Villa Ave, 3rd & Ross LS
Project No: LSP.10
Project Name:
Description:
Priority: Mid-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade X
Engineering Study
Expansion X
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'B'
Engineering 10 % of capital costs
CM & ESDC 18 % of capital costs
Administration 3 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2032
Project Duration (Years): 2
10 of 20
Design-Bid-Build
Comments:
$ 341,000
$ 577,000
$ 2,019,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ 716,000
$ 189,000
$ -
$ 173,000
$ 23,000
$ 1,101,000
$ 110,000
$ 198,000
$ 33,000
Failure Modes & Consequences
Main Lift Station Rehabilitation Project
This project will rehabilitate key electrical, structural, and mechanical systems at the lift station to improve safety, reliability, and long-term performance. Planned improvements include upgrades to site and emergency lighting, replacement of the generator and flow meter, structural repairs to the bar screen vault (including floor grating and access stairs), and enhancements to safety and ventilation systems. Collectively, these improvements will extend facility service life, improve maintainability, and ensure continued reliable operation.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
Main LS
Project No: LSP.11
Project Name:
Description:
Priority: Mid-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade X
Engineering Study
Expansion
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'C'
Engineering 15 % of capital costs
CM & ESDC 20 % of capital costs
Administration 5 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2032
Project Duration (Years): 2
11 of 20
Design-Bid-Build
$ 8,000
Comments:
$ 66,000
$ 94,000
$ 327,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ 10,000
$ 139,000
$ -
$ 5,000
$ 13,000
$ 167,000
$ 25,000
$ 33,000
Failure Modes & Consequences
East Side Lift Station Rehabilitation Project
This project will rehabilitate critical components within the wet well to improve reliability and maintainability. Planned improvements include installation of a backup level element, replacement of suction piping, and rehabilitation of the wet well liner, along with associated bypass pumping to support construction activities. Together, these upgrades will extend the service life of the wet well, reduce operational risk, and ensure continued reliable performance of the lift station.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
East Side LS
Project No: LSP.12
Project Name:
Description:
Priority: Mid-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade X
Engineering Study
Expansion
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'C'
Engineering 15 % of capital costs
CM & ESDC 20 % of capital costs
Administration 5 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2032
Project Duration (Years): 2
12 of 20
Design-Bid-Build
Comments:
$ 62,000
$ 86,000
$ 303,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ 6,000
$ 126,000
$ -
$ -
$ 23,000
$ 155,000
$ 23,000
$ 31,000
$ 8,000
Failure Modes & Consequences
Buena Vista Lift Station Rehabilitation Project
This project will address security, structural, and operational needs at the lift station. Planned improvements include installation of intrusion switches to enhance site security, replacement of wet well access covers to improve safety and maintainability, and spot repairs to the wet well liner to extend structural service life. The project will also include bypass pumping to support construction activities. Together, these improvements will reduce operational risks, improve safety, and ensure reliable facility performance.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
Buena Vista LS
Project No: LSP.13
Project Name:
Description:
Priority: Mid-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade X
Engineering Study X
Expansion X
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'B'
Engineering 10 % of capital costs
CM & ESDC 18 % of capital costs
Administration 3 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2032
Project Duration (Years): 2
13 of 20
Design-Bid-Build
Comments:
$ 148,000
$ 252,000
$ 879,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ -
$ 479,000
$ -
$ -
$ -
$ 479,000
$ 48,000
$ 86,000
$ 14,000
Failure Modes & Consequences
Legacy Lift Station Decommissioning Project
This project will decommission the existing lift station that will no longer required for system operation. Planned work will include permanent disconnection of electrical and mechanical equipment, abandonment or removal of wet well piping, and demolition or filling of below-grade structures as required. Additional work may include site restoration and minor utility rerouting to ensure continuity of service. Collectively, these improvements will safely retire the facility, eliminate ongoing maintenance costs, and reduce long-term operational risk.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
Legacy LS
Project No: LSP.14
Project Name:
Description:
Priority: Mid-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade X
Engineering Study X
Expansion X
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'B'
Engineering 10 % of capital costs
CM & ESDC 18 % of capital costs
Administration 3 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2033
Project Duration (Years): 2
14 of 20
Design-Bid-Build
Comments:
$ 153,000
$ 259,000
$ 905,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ -
$ 493,000
$ -
$ -
$ -
$ 493,000
$ 49,000
$ 89,000
$ 15,000
Failure Modes & Consequences
4th & Wake Lift Station Decommissioning Project
This project will decommission the existing lift station that will no longer required for system operation. Planned work will include permanent disconnection of electrical and mechanical equipment, abandonment or removal of wet well piping, and demolition or filling of below-grade structures as required. Additional work may include site restoration and minor utility rerouting to ensure continuity of service. Collectively, these improvements will safely retire the facility, eliminate ongoing maintenance costs, and reduce long-term operational risk.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
4th & Wake LS
Project No: LSP.15
Project Name:
Description:
Priority: Mid-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade
Engineering Study X
Expansion
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'B'
Engineering 10 % of capital costs
CM & ESDC 18 % of capital costs
Administration 3 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2033
Project Duration (Years): 2
15 of 20
Design-Bid-Build
Comments:
$ 1,823,000
$ 3,083,000
$ 10,788,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ -
$ 130,000
$ -
$ 5,752,000
$ -
$ 5,882,000
$ 588,000
$ 1,059,000
$ 176,000
Failure Modes & Consequences
Force Main Program - Phase 2
This program will replace approximately 12,300 linear feet of downstream force main of Alder Canal - Villa Ave LS to address the existing oversized force main. The project will include installation of new piping designed to accommodate current and future flows, along with bypass pumping to maintain service during construction. Implementation of this program will resolve hydraulic constraints, improve reliability, and ensure the collection system continues to perform effectively under future demand conditions.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
Alder Canal - Villa Ave LS
Project No: LSP.16
Project Name:
Description:
Priority: Long-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade X
Engineering Study
Expansion
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'C'
Engineering 15 % of capital costs
CM & ESDC 20 % of capital costs
Administration 5 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2035
Project Duration (Years): 2
16 of 20
Design-Bid-Build
Comments:
$ 8,000
$ 12,000
$ 40,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ -
$ -
$ -
$ 20,000
$ -
$ 20,000
$ 3,000
$ 4,000
$ 1,000
Failure Modes & Consequences
Gios Lift Station Rehabilitation Project
This project will implement targeted upgrades to improve safety, reliability, and maintainability at the lift station. Planned improvements include installation of an emergency eye wash to improve worker safety, replacement of water service piping to ensure dependable utility connections, and installation of pump lifting chains to facilitate safer and more efficient pump maintenance.
Collectively, these improvements will enhance operational safety, reduce risks, and support reliable long-term performance of the facility.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
Gios LS
Project No: LSP.17
Project Name:
Description:
Priority: Long-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade X
Engineering Study
Expansion
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'B'
Engineering 10 % of capital costs
CM & ESDC 18 % of capital costs
Administration 3 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2035
Project Duration (Years): 2
17 of 20
Design-Bid-Build
Comments:
$ 246,000
$ 416,000
$ 1,455,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ -
$ 207,000
$ -
$ 569,000
$ 17,000
$ 793,000
$ 79,000
$ 143,000
$ 24,000
Failure Modes & Consequences
Lift Station No. 3 Rehabilitation Project
This project will rehabilitate key electrical, structural, and mechanical components of the lift station to improve safety, reliability, and performance. Planned improvements include replacement of wet well lighting, installation of a discharge flow meter with a new vault, site grading to improve drainage and access, and installation of a permanent fixed access ladder for the bar screen motor.
Additional work will include replacement of existing 40-HP pumping units, replacement of wet well access hatches, and provision of bypass pumping to support construction activities. Collectively, these improvements will extend the service life of the facility, enhance worker safety, and ensure continued reliable operation.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
Lift Station No. 3
Project No: LSP.18
Project Name:
Description:
Priority: Long-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade X
Engineering Study
Expansion
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'C'
Engineering 15 % of capital costs
CM & ESDC 20 % of capital costs
Administration 5 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2036
Project Duration (Years): 2
18 of 20
Design-Bid-Build
Comments:
$ 70,000
$ 98,000
$ 344,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ -
$ 142,000
$ -
$ 34,000
$ -
$ 176,000
$ 26,000
$ 35,000
$ 9,000
Failure Modes & Consequences
8th & Wake Lift Station Rehabilitation Project
This project will replace the existing 5-HP pumps to improve reliability and maintainability of the lift station. The pump replacement will extend equipment service life, reduce the risk of unplanned failures, and ensure continued reliable operation of the facility.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
8th & Wake LS
Project No: LSP.19
Project Name:
Description:
Priority: Long-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade X
Engineering Study X
Expansion X
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'C'
Engineering 15 % of capital costs
CM & ESDC 20 % of capital costs
Administration 5 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2037
Project Duration (Years): 2
19 of 20
Design-Bid-Build
Comments:
$ 155,000
$ 218,000
$ 761,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Project Cost:
$ 60,000
$ 219,000
$ -
$ 109,000
$ -
$ 388,000
$ 58,000
$ 78,000
$ 19,000
Failure Modes & Consequences
Alder Canal - Villa Ave Lift Station Rehabilitation Project This project will rehabilitate key electrical, structural, and site components of the lift station to improve safety, reliability, and performance. Planned improvements include verification of the drywell flood alarm and integration with the RTU, redesign and installation of LED lighting in the drywell, and drainage and grading improvements to prevent water infiltration. Additional work will include installation of outdoor lighting at the chemical area, replacement of exterior and interior lighting at the electrical building, installation of a discharge flow meter with a new vault, and site grading improvements. Station bypass pumping will be provided to support construction activities.
Collectively, these improvements will extend the service life of the facility, enhance worker safety, and ensure continued reliable operation.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
Alder Canal - Villa Ave LS
Project No: LSP.20
Project Name:
Description:
Priority: Long-term Funding: WW
Location/Facility:
Project Origin: El Centro Lift Stations Condition Assessment Project Type: Project Driver(s):
Rehab/Replacement X
Facility/Equip Upgrade X
Engineering Study X
Expansion X
Construction Costs:
General
Site Civil & Mechanical
Structural
Electrical, Instrumentation & Controls
Equipment
Construction Cost Subtotal:
Soft Costs:
Classification 'C'
Engineering 15 % of capital costs
CM & ESDC 20 % of capital costs
Administration 5 % of capital costs
Soft Cost Subtotal:
Contingency:
Contingency 40 % of project cost
Total Project Cost:
Project Implementation:
Project Delivery Method:
Project Start Year: 2037
Project Duration (Years): 2
20 of 20
$ -
$ 35,000
$ 5,000
$ 7,000
$ 2,000
Comments:
$ 14,000
$ 20,000
$ 69,000
Project Implementation (Schedule & Expenditure Timeline) One-Time Project
Design-Bid-Build
Project Cost:
$ 7,000
$ -
$ -
$ 28,000
Failure Modes & Consequences
3rd & Ross Lift Station Rehabilitation Project
This project will implement targeted upgrades to improve safety, reliability, and maintainability of the lift station. Planned improvements include installation of new site task lighting and provision of an on-site water connection to support facility operations and maintenance. Collectively, these improvements will enhance worker safety, improve operational efficiency, and ensure continued reliable performance of the facility.
Predicted Useful Life Expiration
Condition Assessment
Operations Assessment
3rd & Ross LS
Appendix B
Wastewater Treatment Plant Condition Assessment
Technical Memorandum
15092 Avenue of Science, Suite 200
San Diego, CA 92128
NV5 PROJECT NUMBER 2810224-0001977.00
TECHNICAL MEMORANDUM
EL CENTRO WASTEWATER TREATMENT PLANT – CONDITION ASSESSMENT November 2025
Prepared For:
City of El Centro
1275 Main Street
El Centro, CA 92243
Dudek
605 Third Street
Encinitas, CA 92024
Project Number 2810224-0001977.00 NV5.COM | i
TABLE OF CONTENTS
1.0 Introduction.............................................................................................................................. 1
1.1 Objectives .......................................................................................................................................... 1
1.2 Background ....................................................................................................................................... 1
1.3 Overview of Existing WWTP Process ............................................................................................. 1
1.3.1 Pretreatment ............................................................................................................................ 1
1.3.2 Primary Treatment................................................................................................................... 2
1.3.3 Secondary Treatment and Disinfection................................................................................ 2
1.3.4 Sludge Treatment .................................................................................................................... 2
2.0 Existing Facilities and condition evaluation ....................................................................... 4
2.1 Headworks......................................................................................................................................... 4
2.2 Influent Distribution Structure........................................................................................................ 5
2.3 Primary TREATMENT........................................................................................................................ 8
2.3.1 Primary Clarifier Mechanical Equipment ............................................................................. 9
2.3.2 Primary Clarifier Gallery Piping and Sludge Pumps........................................................... 9
2.4 SECONDARY TREATMENT .............................................................................................................11
2.4.1 Aeration Basins ......................................................................................................................11
2.4.2 Aeration System.....................................................................................................................12
2.5 Secondary Clarifiers.......................................................................................................................14
2.5.1 Splitter Boxes..........................................................................................................................14
2.5.2 Secondary Clarifiers...............................................................................................................16
2.5.3 Plant Water Pump Station and Raw Water Supply..........................................................17
2.5.4 Sludge Pump Room...............................................................................................................18
2.6 UV Disinfection System .................................................................................................................21
2.7 Sludge Digesters.............................................................................................................................22
2.7.1 Digester Tanks........................................................................................................................22
2.7.2 Digester Mixing Systems ......................................................................................................25
2.7.3 Sludge Treatment Infrastructure.........................................................................................26
2.7.4 Digested Gas Piping and Burner..........................................................................................28
2.7.5 Digesters Site .........................................................................................................................29
2.8 Solids handling and dewatering...................................................................................................30
2.8.1 Gravity Belt Thickeners .........................................................................................................30
2.8.2 TWAS Pumps ..........................................................................................................................33
2.8.3 Sludge Dewatering Belt Filter Presses ...............................................................................34
2.8.4 Sludge Drying Bed..................................................................................................................37
2.9 Buildings ..........................................................................................................................................37
2.9.1 Blower Building ......................................................................................................................37
2.9.2 Main Office Building ..............................................................................................................38
3.0 Preliminary Capacity Assessment .....................................................................................39
Project Number 2810224-0001977.00 NV5.COM | ii
3.1 Data Acquisition .............................................................................................................................39
3.2 Flow Scenarios................................................................................................................................39
3.3 main TREATMENT PROCESSes CAPACITY ASESSMENT ..........................................................40
3.3.1 Primary Clarifiers ...................................................................................................................40
3.3.2 Aeration Basins ......................................................................................................................41
3.3.3 Secondary Clarifiers...............................................................................................................42
3.4 Summary of Results and recommendations.............................................................................43
3.4.1 Primary Clarifiers Capacity Alternatives.............................................................................44
4.0 Recommendations ...............................................................................................................47
4.1 HEADWORKS AND Primary Treatment.......................................................................................47
4.2 Secondary Treatment ....................................................................................................................49
4.2.1 Aeration Basins ......................................................................................................................49
4.2.2 Secondary Clarifiers and Ancillary Pumps .........................................................................49
4.3 Solids Treatment............................................................................................................................51
4.3.1 Digesters .................................................................................................................................51
4.3.2 Gravity Belt Thickeners .........................................................................................................53
4.3.3 Dewatering..............................................................................................................................54
4.4 Operations Building Improvements.............................................................................................55
LIST OF TABLES
Table 1 – Flow Scenarios
Table 2 – Preliminary Capacity Assessment of Primary Clarifiers Table 3 –Dimensions of Aeration Basins
Table 4 – Preliminary Capacity Assessment of Aeration Basins Table 5 – Preliminary Capacity Assessment of Secondary Clarifiers Table 6 – Preliminary Capacity Assessment Results Summary Table 7 – Characteristics of Existing and Proposed Primary Clarifiers Table 8 - Headworks and Primary Treatment Recommended Improvements Table 9 - Aeration Basins Recommended Improvements
Table 10 - Secondary Clarifies Recommended Improvements Table 11 - Digesters Recommended Improvements
Table 12 - Gravity Belt Thickener Recommended Improvements Table 13 - Dewatering Recommended Improvements
Table 14 - Buildings Recommended Improvements
LIST OF FIGURES
Figure 1 – Existing Process Flow Diagram
Project Number 2810224-0001977.00 NV5.COM | 1
1.0 INTRODUCTION
1.1 OBJECTIVES
The primary objectives of this technical memorandum (memo) are to 1) describe the existing infrastructure, 2) describe the condition of existing infrastructure, 3) provide a planning level capacity assessment, and 4) recommend improvements for the El Centro Wastewater Treatment Plant.
1.2 BACKGROUND
The City of El Centro (City) is in Imperial County approximately 120 miles east of San Diego, CA and approximately 60 miles west of Yuma, AZ. The City is approximately 11.1 square miles in area and lies approximately 42 feet below sea level. The population of the City is approximately 44,322 as reported by the 2020 United States Census. The City operates and maintains a wastewater collection system and the El Centro Wastewater Treatment Plant (WWTP) located at 2255 North La Brucherie Road.
The WWTP was originally constructed in 1957 with two primary clarifiers, oxidation ponds (lagoons), two sludge digesters, and sludge drying beds. In 1972 the ponds were replaced with a secondary treatment system consisting of four aeration basins and two secondary clarifiers and a chlorine contact basin for disinfection. In 1989 the sludge treatment system was upgraded with the addition of a belt filter press and a third larger digester equipped with a gas mixing system. A sludge heating system for the digesters was also added at that time. In 1994, the last major plant improvements included two additional aeration basins, two additional secondary clarifiers, a gravity belt thickener, and a gas mixing system for Digester No. 2 among many other improvements. In 1997 an ultraviolet disinfection unit was added to replace the chlorine contact basin. In 2009 redundancy improvements were constructed including a second belt filter press unit, a second gravity belt thickener, and a second ultraviolet disinfection unit. In 2017 two blowers were replaced.
The WWTP currently receives an average wastewater flow of approximately 3.52 million gallons per day (mgd) but has capacity and is permitted for an average flow up to 8.0 mgd.
1.3 OVERVIEW OF EXISTING WWTP PROCESS
The WWTP uses a conventional activated sludge process for wastewater treatment. Per the City, the current treatment process works well and the WWTP can consistently produce secondary effluent meeting all discharge requirements. A process flow diagram of the existing treatment process is shown in Figure 1, and a brief description of the process is provided below.
1.3.1 Pretreatment
The WWTP receives screened wastewater collected throughout the City and conveyed through gravity sewer mains and lift stations, and ultimately from two lift stations, the Main Lift Station located offsite and Lift Station No. 3, located at the WWTP. The Main Lift Station conveys approximately 80% of the City’s wastewater to the WWTP. Each lift station has a mechanical bar screen with washer/compactor equipment located upstream of the wet well. Wet screenings collected in the bar
Project Number 2810224-0001977.00 NV5.COM | 2
screens are washed and compacted to reduce their volume. Compacted solids are collected in a portable bin container, where they are stored prior to being disposed of at a private landfill.
Screened wastewater pumped from the two lift stations combine into a single 24-inch influent force main which runs through a magnetic flow meter located before the influent distribution center.
Influent flow measurements are logged on a chart recorded at the control room. The flow then enters the influent distribution structure between the two primary clarifiers. At the influent structure, ferric chloride and polymer are injected for coagulation. The flow is then distributed to the primary clarifiers.
1.3.2 Primary Treatment
There are two circular primary clarifiers at the WWTP. Effluent flows over the weirs into the launder troughs that flow into a separate chamber in the influent distribution structure. From the distribution structure, wastewater flows by gravity to the aeration basins via a 30-inch diameter pipe. Primary sludge collected at the bottom of the clarifiers is pumped to the digesters with two plunger type (suction and discharge flange) pumps. Grease from the primary clarifiers is skimmed into a collection box and removed into a dumpster for disposal at the local landfill.
1.3.3 Secondary Treatment and Disinfection
Secondary (activated sludge) treatment consists of six aeration basins and four secondary (final) clarifiers. Existing influent and effluent channels provide the flexibility of operating the aeration basins in parallel or as a series of reactors. Air is provided to the aeration basins through a system of blowers, pipes and fine bubble diffusers located at the bottom of the aeration basins. Effluent from the aeration basins flows by gravity to a splitter box for distribution to the four secondary clarifiers. Effluent from each of the secondary clarifiers flows over the weirs into the effluent launders and flows to a junction box located north of the secondary clarifiers. Secondary effluent then flows by gravity to the ultraviolet (UV) disinfection facility located at the north end of the site, which has two UV units installed in parallel for disinfection. Disinfected secondary treated wastewater is then discharged into the nearby Central Main Drain, an agricultural drainage channel which is tributary to the Alamo River.
Activated sludge collected off the bottom of the secondary clarifiers flows into the wet well of the sludge pump room which pumps return activated sludge to the aeration basins and pumps waste activated sludge to the gravity belt thickeners.
1.3.4 Sludge Treatment
Sludge treatment consists of thickening, anaerobic digestion, and dewatering. Primary and waste activated sludge are stabilized through digestion and excess water is removed before final disposal.
A brief description of the sludge handling and treatment process and existing equipment follows.
Waste activated sludge (WAS) at approximately 1% solids content is pumped from the sludge pump room into a gravity belt thickener (total of two gravity belt thickener units: one duty, one standby).
WAS is treated with polyacrylamide emulsion polymer (Clarifloc S462) to enhance the removal of water and then thickened using a gravity belt thickener. Thickened waste activated sludge (TWAS) is
Project Number 2810224-0001977.00 NV5.COM | 3
then pumped to the anaerobic digesters by two plunger type pumps, where it mixes with primary sludge from the primary clarifiers. The sludge in the digesters is typically around 3% solids content.
There are three anaerobic digestion tanks at the treatment facility used for sludge stabilization and storage including two primary digesters (Digester Tank No. 1 and Digester Tank No. 2) and one storage digestor (Digester Tank No. 3). Each primary digester has a gas mixing system and there is a centralized sludge heating/recirculation system for both primary digesters. The two primary digesters are currently operating in series. Primary sludge and TWAS are first pumped into Digester Tank No. 1, the largest tank. Then, digested sludge from Digester Tank No. 1 flows by gravity to Digester Tank No. 2. Digested sludge from Digester Tank No. 2 then flows by gravity to Digester Tank No. 3 for final sludge consolidation and storage. Digested sludge from Digester Tank No. 3 is then pumped to the belt filter press (total of two gravity belt thickener units: one duty, one standby) for dewatering. Digested sludge is also periodically pumped from Tank No. 1 and No. 2 to the belt filter press. Dewatered sludge from the filter press is then loaded into dump trucks which haul the sludge to the sludge drying bed located on site for final dewatering. After final dewatering the dried sludge is then transported to Arizona for land disposal.
The digesters were originally designed to collect and return supernatant back to the primary influent structure. However, supernatant is no longer part of the current digester process which produces a more homogeneous sludge mixture.
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2.0 EXISTING FACILITIES AND CONDITION EVALUATION
A description of the existing treatment processes and condition assessment based on visual inspection and information received from WWTP operation staff is summarized below.
2.1 HEADWORKS
The headworks facilities at the WWTP site consist of a bar screen structure upstream of Lift Station No. 3 which screens approximately 20% of the influent (gravity flow) into the facility. Most of the influent (approximately 80%) is screened at the Main Lift Station (offsite) and pumped through a force main directly into the WWTP influent structure. This section covers the bar screen at the WWTP.
The bar screen structure is equipped with a mechanical bar screen to remove solids and a washer/compactor to clean and reduce the volume of screenings. The compacted screenings are collected in a portable waste container that is emptied and hauled to a private landfill. Screened wastewater flows by gravity to Lift Station No. 3, is pumped, and combines with screened wastewater from the Main Lift Station in a 24-inch influent force main that flows to the influent distribution structure. A magnetic flow meter is installed on the 24-inch force main just upstream of the influent structure to meter the influent flow into the plant.
Due to high H2S off-gassing of the influent sewer and hazardous conditions it creates, entry to the bar screen structure is restricted access (confined space), therefore the condition of the interior of the structure was not assessed as part of this study. Following confined space entry procedures, plant operators enter the structure approximately twice a year to inspect the interior equipment and structure. Based on conversations with the plant supervisor, the equipment and structure are in good condition, except for grating hardware that has corroded due to the corrosive environment.
A visual inspection was completed of the exterior of the bar screen structure, access stairs and door, and above ground equipment (see photos below). The bar screen exterior and the washer/compactor have rust staining from leaking but are operating without issues. The access door interior hardware has corroded, including the intrusion switch, requiring the door to be propped closed from the exterior with a wood post. In addition, the floor drain at the access staircase landing is clogged with dirt and debris which could result in accumulation of rainwater by the access door.
The condition assessment of Lift Station No. 3 is covered separately and is not included in this report.
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2.2 INFLUENT DISTRIBUTION STRUCTURE
The influent distribution structure is a reinforced concrete structure located between the two primary clarifiers, all of which were constructed in 1957. The structure, which has multiple chambers, splits screened influent to the two primary clarifiers and receives the effluent from each clarifier before it is conveyed to the aeration basins. Record structural drawings for the structure were not available, but based on available improvement plans, the structure has a footprint of 12 ft by 13 ft and has 12- inch-thick side walls with a total height of 18.5 ft (approximately 12 ft of which is below grade).
Ferric chloride and polymer are added to the influent from chemical totes and chemical feed pumps located at the influent structure.
Per WWTP staff, the interior of the structure has not been cleaned or inspected in recent history. A detailed inspection of the structure exterior was not conducted for this study, but in general the exterior of the concrete walls are in poor condition. There is a very large crack, and the concrete is spalling on the east wall of the structure. The concrete roof deck appears to be in poor condition with visible cracking. WWTP staff also indicated that the storm drain inlets and pipelines between the digesters and the influent structure are clogged.
A detailed inspection of the structure exterior and interior should be conducted by a structural engineer when the structure is emptied and cleaned, but it appears that at least the top portion of the walls and the roof deck should be replaced with new concrete. In addition, many of the metallic/safety components (grating, handrail, light pole, shade structure, and sampling shed Wood post holding
access door closed
Floor drain
clogged with dirt
and debris
Rust staining
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platform) show heavy rust and should be replaced. The condition of the five sluice gates is unknown but it is assumed that they also need to be replaced. All temporary hoses should be replaced with permanent piping and the existing chemical feed pumps should be permanently mounted. The existing 6-inch diameter digester supernatant pipeline (blue pipe in image below) is not active and abandoned in place, removal and disposal is recommended.
Large crack/
spalling
Ferric
chloride
chemical
feed
pumps and
tubing
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Heavy rust on sluice
gate handles and
railings
Cracking on
roof deck
Inactive digester
supernatant pipe
(Blue Pipe)
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2.3 PRIMARY TREATMENT
The two primary clarifiers are circular reinforced-concrete clarifiers with v-notch weirs originally constructed in 1957. Each clarifier has an interior diameter of 65 ft with 10-inch-thick weir walls and a side water depth of 8.75 ft. Each clarifier The overflow rate of each clarifier is 1,205 gpd/ft2 at the permitted flow of 8 mgd. The total exterior diameter of each clarifier is 71.5 ft, including the integral effluent launders (troughs) which have 8-inch-thick exterior walls. Per WWTP staff, the top portion of the effluent launder walls for both clarifiers were reconstructed after the 2010 earthquake. A detailed inspection of the primary clarifier structure was not conducted for this technical memo, but in general the reconstructed effluent launder walls appear to be in good condition based on a visual inspection. However, some of the original concrete that is visible has large cracks and is spalling, such as the scum box walls for each clarifier. The weir of Clarifier No. 2 is clogged with grease, causing some of the v-notches to not flow. The weirs of Clarifier No. 1 are in better condition with less overall clogging. Clarifier No. 1 also appears to receive more flow than Clarifier No. 2 which could indicate a flow splitting issue.
Per WWTP staff, the primary clarifiers operate over capacity during wet weather conditions. During heavy rain events, operations personnel throttle back the pumps at the Main Lift Station and use the collection system for storage to attenuate peak flows to the WWTP.
A detailed inspection of the clarifier exterior and interior should be conducted by a structural engineer when the structure is emptied and cleaned, but some concrete rehabilitation is needed.
Primary
Clarifier
No. 1
Primary
Clarifier
No. 2
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2.3.1 Primary Clarifier Mechanical Equipment
The mechanisms for both clarifiers, including the drive unit, center column, feed well, scraper arms, skimmer arms, and associated components were last replaced in 1989 with Eimco (now Ovivo) clarifier mechanisms. The mechanisms are operable, but the exposed parts show heavy rust and should be replaced. The access bridge/walkway and drive platform are also in poor condition and should be replaced at the same time. The coated steel v-notched weirs and scum baffles appear to be in fair condition but are recommended to be replaced with the clarifier equipment and bridge to take advantage of the process shutdown and for cost effectiveness.
2.3.2 Primary Clarifier Gallery Piping and Sludge Pumps The primary clarifier gallery, also constructed in 1957, is a reinforced concrete structure located between the two primary clarifiers and shares a common wall with the influent distribution structure on the west side of the gallery. The exposed walls and roof deck appear to be in fair condition.
However, a detailed inspection should be conducted by a structural engineer.
The gallery contains multiple exposed process pipes including the 24-inch screened influent pipe, 6- inch primary sludge piping, 6-inch scum piping, and other active process pipes (water, drain, and sump pump discharge piping). The gallery also contains inactive 6-inch digester supernatant return piping and inactive 6-inch recirculation piping, which are no longer used for the current WWTP process. The 24-inch influent line includes an 18-inch magnetic flow meter (with 24x18 reducers) which was manufactured in 2008. There is a section of the main influent line is partially supported by six wooden boards stacked on top of one another.
Primary Clarifier No. 1
Primary Clarifier No. 2
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Primary sludge pumps and associated primary sludge and scum piping are located on the roof deck of the gallery. The two primary sludge pumps were recently replaced by the WWTP staff. One of the pumps is a Lobe Pro SM50 rotary pump (serial number 103104). The second pump is a Vogelsang (serial number 11-09623) that has not been permanently mounted yet. Both pumps have temporary flexible piping and temporary supports. The control panels for both pumps are exposed to the sun and unprotected.
The exterior condition of the gallery and sludge pump piping varies but is in poor condition overall and the interior condition is unknown. All the smaller diameter piping (6-inch and less), valves, and appurtenances should be replaced and piping that is no longer necessary for the current or future operation should be removed, including the 6-inch supernatant piping that is no longer in use. The interior condition of the 24-inch influent line should be inspected before determining if the pipeline should be rehabilitated or replaced. At a minimum, the exterior of the 24-inch pipe should be recoated. The City is considering replacing the 18-inch flow meter due to its age. Wood blocks supporting the influent pipeline should be replaced with concrete or steel supports. The controls for the new primary sludge pumps should also be covered to protect the equipment, and all temporary hoses should be replaced with coated metal piping.
Primary Clarifier Gallery
Stack of 6 wood beams
supporting 24-inch influent
pipeline
18-inch
Flow meter
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2.4 SECONDARY TREATMENT
2.4.1 Aeration Basins
The secondary treatment process includes six aeration basins operating in series. Aeration Basins No. 1 through 4 were installed in 1972 and Aeration Basins No. 5 and 6 were added to the secondary treatment process by repurposing two basins formerly used for aerobic sludge digestion. (1994 upgrade). Aeration Basins No. 1 through 4 are 50 ft by 50 ft basins with a side water depth (SWD) of 12.05 ft, providing a total volume of 120,500 ft3. Aeration Basins No. 5 and 6 are 55 ft by 55 ft with a SWD of 12.05 ft, which provide a total volume of 72,903 ft3. The six aeration basins have a combined volume of 193,403 ft3.
Effluent from the primary clarifiers enters the influent distribution structure which flows into the aeration basin influent channel. Existing influent and effluent channels provide the flexibility of operating the aeration basins in parallel or in series and provide flexibility to operate the basins in different combinations.
A visual inspection of the main components of the aeration basins was conducted during the site visit, and information on known issues provided by WWTP operators documented. Six sluice gates in the aeration basin were replaced in 2020. The remaining 36 sluice gates are in poor condition and should be replaced. The interior condition of the basins is unknown and should be inspected during maintenance. Some of the exterior walls of the aeration basins are in poor condition with spalling and cracks that should be repaired. The concrete platforms for the mechanical mixers (no longer in place) are not in use and deteriorating, with concrete spalling and rebar visible. The 16-inch return activated sludge (RAS) piping is halfway submerged in the aeration basin influent channel and in poor condition. The RAS piping should be replaced and positioned outside of the water.
Piping
partially
supported
by bucket
New pump
controls with
no cover
Vogelsang
pump is not
mounted
Piping
partially
supported
by bucket
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2.4.2 Aeration System
Air is supplied to the aeration basins through a system of blowers, aeration headers and distribution piping, and fine bubble diffusers. Above ground stainless-steel aeration piping is in good condition, including pipe supports and isolation valves. Per WWTP staff, a small number of aeration heads have detached from diffusers due to age and condition, which have been replaced when basins are drained. WWTP staff also indicated that air piping within the basins is in poor condition and in need of replacement.
Three blowers (two duty, one standby) supply air to the aeration basins and are housed inside a building by the aeration basins. Blowers No. 1 and 2 were replaced in 2019 with variable frequency drive (VFD) Sulzer blowers and integrated into an automated most open valve system to better meet oxygen demand in the aeration basins and reduce energy consumption. Blowers No. 1 and No. 2 are Sulzer model number HST9500-U250-1-L-48 (serial number 100193999 and 100193998 respectively). Blower No. 3 remained as a standby but is currently not operational and disconnected from the aeration system. A temporary blower was installed outside under a shade structure as standby while Blower No. 3 is replaced. The temporary blower is a 250 HP Siemens PE 21 Plus blower (type RGZESD). Replacement of Blower No. 3 is currently under design with the same Sulzer VFD blower model as Blowers No. 1 and 2, including required air discharge piping modifications. The blower replacement design also includes a permanent concrete ramp for the blower west rollup door entrance, to replace a temporary gravel ramp (see photo below). Once Blower No. 3 is replaced, the temporary blower will be removed.
Effluent gate
in poor
condition
Cracking
concrete/exposed
rebar
Project Number 2810224-0001977.00 NV5.COM | 13
Air supplied by the three blowers enters a 24-inch header pipe into the aeration basins. From the header pipe, branch lines supply air to each basin, through a 12-inch pipe for aeration basins No. 1 through 4, and through a 14-inch pipe for aeration basins No. 5 and No. 6. These pipes provide air to the diffusers located at the bottom of the aeration basins. Manually operated butterfly valves are provided at each basin to shut down air supply if needed. Motor actuated valves at each basin automatically modulate air volume into each basin based on dissolved oxygen levels.
Temporary Gravel
Ramp Ramp
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2.5 SECONDARY CLARIFIERS
2.5.1 Splitter Boxes
Effluent from the aeration basins flows by gravity through a series of splitter boxes before entering the four secondary clarifiers. The influent first enters a central splitter box that distributes flow to two secondary splitter boxes (east and west) which distribute flow to the clarifiers. The west splitter box distributes flow to Clarifiers No. 1 and 2 while the east splitter box distributes flow to Clarifiers No. 3 and 4. The west splitter box was installed in 1972 with Clarifiers No. 1 and 2. The central splitter box and east splitter box were later installed in 1994 when Clarifiers No. 3 and 4 were installed at the WWTP.
The exterior of the central splitter box structure appears to be in good condition. Per WWTP staff, the sluice gates on the central splitter box are in poor condition and should be replaced. The west splitter box structure is in poor condition with large visible cracking and should be replaced. The west splitter box sluice gates are also in poor condition and should be replaced. The east splitter box structure and sluice gates appear to be in good condition.
Inactive
Blower No. 3
Temporary Blower
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Central Splitter
Box
West Splitter
Box
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2.5.2 Secondary Clarifiers
There are four circular secondary clarifiers with v-notch weirs. Clarifiers No. 1 and 2 were installed in 1972 and Clarifiers No. 3 and 4 were later constructed during the 1994 upgrade. During the summer, all four clarifiers are typically run to protect the equipment from the sun, and during the winter, three clarifiers are typically run. The secondary clarifiers have a diameter of 80 ft, an average SWD of 9.95 ft, and provide a total volume of 200,057 ft3. They are designed to operate at a hydraulic detention time of 4.5 hours, with an overflow rate of 400 gpd/ft2 and a weir loading rate of 7,958 gal/ft-day at the design flow of 8 mgd. The sludge collected from the bottom of the secondary clarifiers flows into four sludge diversion lines that flow into the sludge pump room wet well where some sludge will become return activated sludge (RAS) and pumped back into the aeration basins.
Clarifiers No. 1 and 2 have 10-inch sludge diversion lines and Clarifiers No. 3 and 4 have 18-inch sludge diversion lines.
Effluent from each of the secondary clarifiers flows over the weirs into the effluent launder and into 18-inch pipes. The effluent from Clarifiers No. 3 and 4 is combined into a 24-inch pipe, and the effluent from Clarifiers No. 1 and 2 is combined into a separate 24-inch pipe. Both secondary effluent pipes flow into the wet well of the Plant Water Pump Station located northwest of the secondary clarifiers. From the Plant Water Pump Station wet well, secondary effluent flows by gravity to the to the ultraviolet (UV) disinfection system through a 30-inch pipe.
The equipment in Clarifiers No. 3 and 4 was refurbished in 2020, and Clarifiers No. 1 and 2 were refurbished in 2024. Refurbishments included replacing the arms, drum, box, standpipe, and gears East Splitter
Box
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for each clarifier. Clarifier No. 4 was out of service and drained during a site visit on January 23, 2025. The interior structure and equipment appeared to be in good condition. The secondary clarifiers overall appear to be in good condition.
2.5.3 Plant Water Pump Station and Raw Water Supply
The plant water pump station is located northwest of the secondary clarifiers next to the inactive chlorine contact basin. The plant water pump station provides process water to various treatment processes (sludge thickening and dewatering, and spray water for the primary and secondary treatment processes). The plant water pump station reinforced concrete structure originally constructed in 1972, but the pumps and the above grade piping were replaced in 1994. The pump station has two vertical turbine pumps, Plant Water Pumps No. 1 and 2, which are mounted to the roof deck of the pump station wet well. Plant Water Pump No. 1 is the backup pump (model number JMM3312T, serial F0505230800) and Plant Water Pump No. 2 is the main operating pump (model number 2VD 215TTFL7009DB L).
The visible portion of the pump station structure, the concrete roof deck, is in very poor condition with severe cracking and spalling concrete. A detailed inspection of the structure exterior and interior should be conducted by a structural engineer when the structure is emptied and cleaned, but as a minimum the roof deck should be replaced. Per WWTP staff, the pumps, piping, and other equipment at the plant water station are all in fair condition. However, the City should consider replacing the other equipment at the plant water pump station when the roof deck is replaced.
Clarifier No. 2
Skimmer
Clarifier No. 4
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The WWTP has a water connection to the Imperial Irrigation District raw water (untreated) system pipeline (gravity system) along La Brucherie Road, which is used for landscape irrigation within the plant. A booster pump system adjacent to the raw water connection (by the main access road entrance to the facility) pressurizes and supplies the irrigation system.
2.5.4 Sludge Pump Room
The sludge pump room is a below grade structure located between Secondary Clarifiers No. 1 and 2 and was constructed in 1972. The room has a footprint of 29.5 feet by 31 feet with 16-inch-thick side walls and has a total height of approximately 15 feet. RAS Pumps No. 1 and 2 were installed and a stub out was installed for a future RAS pump. Waste Activated Sludge (WAS) Pumps No. 1 and 2 were also installed. RAS Pump No. 3 was installed between 1972-1994. In 1994, RAS Pumps No. 1 and 2 and WAS Pumps No. 1 and 2 were replaced along with their associated equipment pads and piping, and a 3-foot by 8-foot aluminum roof access hatch in the southwest corner of the structure.
The northwest roof access hatch (4-ft x 4-ft) appears to be in fair condition with horizontal cracking on the inner concrete which should be repaired. The concrete curb surrounding the southwest aluminum hatch has large cracks on the northwest edge of the curb and should be rehabilitated.
RAS Pumps No. 1, 2, and 3 are Gorman Rupp self-priming centrifugal pumps (Model No. T10A3-B) and appear to be in good condition, including the piping. The concrete pad for RAS Pump No. 1 appears to be in good condition, but the concrete pads for RAS Pumps No. 2 and 3 have cracks and should be repaired.
WAS Pumps No. 1 and 2 are Gorman Rupp self-priming centrifugal pumps (Model No. T4A3-B) and appear to be in good condition, including suction and discharge piping. The concrete pads for WAS Pumps No. 1 and 2 appear to be in poor condition with multiple large cracks in the concrete pads and should be replaced.
Pump station roof deck
with cracked and
spalling concrete
Inactive chlorine
contact basin
Project Number 2810224-0001977.00 NV5.COM | 19
Cracking concrete
curb around
access hatch
Uncovered
sump pump
Horizontal cracking in
concrete
Project Number 2810224-0001977.00 NV5.COM | 20
RAS Pump No. 1 RAS Pump No. 2
RAS Pump No. 3 45-degree bend
in piping
Cracking
concrete pad
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2.6 UV DISINFECTION SYSTEM
Disinfection is achieved with two ultraviolet (UV) units installed in parallel. One of the UV units was installed in 1997 and the second was installed in 2009. The existing UV units are the UV40000 model manufactured by Trojan Technologies, Inc (Trojan). The UV disinfection channel and units are located near the north side of the treatment plant site. The existing UV units are mounted on an open concrete channel that is 4 ft wide and 70 ft long with a depth of 9 ft. Each UV reactor, located inside the channel, is a contact type reactor with lamps encased in a quartz sleeve and positioned parallel to the flow direction. Each unit consists of two banks of lamps, each having four modules and each module has four lamps. The UV units provide a UV radiation intensity of 125 mW/cm2 and the administered dose is dependent on the wastewater flow through the system.
The City is currently in the process of replacing both existing UV units with new TrojanUV Signa units manufactured by Trojan. The construction for the upgraded UV disinfection system is currently ongoing. The UV replacement project will also include modifications to the existing UV channels and two small, prefabricated buildings for electrical and controls equipment for the new UV system. The existing UV structure and metal shade structure over the UV units are in good condition.
WAS Pump No. 1
Cracking
concrete pad
WAS Pump No. 2
Cracking
concrete pad
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2.7 SLUDGE DIGESTERS
2.7.1 Digester Tanks
Digester Tank No. 1, a circular reinforced concrete tank constructed in 1989, has an interior diameter of 60 ft, 16-inch-thick side walls with a height of 30 ft (approximately 9 ft of which is below grade), a relatively flat floor, an integral domed reinforced concrete cover, and an approximate working volume of 590,000 gal. The tank was last cleaned and re-lined in 2001. Per WWTP staff the lining appeared to be in good condition during a 2015 inspection. The interior of the tank has not been inspected since then. A detailed inspection of the tank exterior was not conducted for this tech memo, but in general the exterior of the concrete walls appears to be in good condition. The cementitious coating is delaminating in some areas and should be repaired. There are also some cracks showing efflorescence and rust staining that should be examined closer and potentially repaired. A detailed inspection of the tank exterior and interior should be conducted by a structural engineer when the tank is emptied and cleaned.
UV channels
and effluent
sampler
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Digester Tank No. 2, a circular reinforced concrete tank constructed in 1957, has an interior diameter of 40 ft, 12-inch-thick side walls with a height of 21.5 ft (approximately 2 ft of which is below grade), a hopper bottom which extends down another 5 ft below grade, and an approximate working volume of 200,000 gal. The tank has a flat reinforced concrete cover which was constructed in 1994 to replace the original floating cover. Per record drawings the cover has a Tlock PVC liner. Per WWTP staff, the interior of the tank has not been cleaned, inspected, or lined in recent history. A detailed inspection of the tank exterior was not conducted for this tech memo, but in general the exterior of the concrete walls appears to be in fair condition. The exterior coating is delaminating in many areas and should be re-coated. There are some horizontal cracks showing under the coating that may need to be repaired prior to re-coating. The tank cover does not appear to be fully sealed, indicating the sealant between the tank walls and cover should be replaced. In addition, the concrete cover has some areas of surface delamination and cracking that should be repaired. A detailed inspection of the tank exterior and interior should be conducted by a structural engineer when the tank is emptied and cleaned.
There are four 36-inch manways on the tank cover for access. WWTP staff stated that they would like to retrofit a new access point on the side wall of the tank, like Tank No. 1 which has two hatches, each a few feet above grade. However, retrofitting a new access hatch is not recommended because it would be difficult to provide steel reinforcement around the new opening, coring and testing of concrete would be required, record structural plans for the tank are not available and destructive testing would be needed to identify the location and size of steel reinforcement, the interior condition of the tank walls is unknown, and the tank is approximately 68 years old.
Delaminating coating
Cracks with efflorescence
and rust staining
Project Number 2810224-0001977.00 NV5.COM | 24
Digester Tank No. 3, a circular reinforced concrete tank, also constructed in 1957, has an interior diameter of 40 ft, 12-inch-thick side walls with a height of 21 ft (approximately 2 ft of which is below grade), a hopper bottom which extends down another 4.5 ft below grade, and an approximate working volume of 190,000 gal. The tank has a floating steel cover which was installed in 1994 to replace the original floating cover. Like Tank No. 2, the interior of the tank has not been cleaned, inspected, or lined in recent history. Portions of the tank interior visible above the floating cover appear to be in fair condition. There are some old anchor points showing rust stains that should be inspected closer and may need to be repaired if the rust is coming from rebar. A detailed inspection of the tank exterior was not conducted for this tech memo, but in general the exterior of the concrete walls appears to be in fair condition. The exterior coating is delaminating in some areas and should be recoated. There are some horizontal cracks showing under the coating that may need to be repaired prior to re-coating. A detailed inspection of the tank exterior and interior should be conducted by a structural engineer when the tank is emptied and cleaned. The coated steel floating cover is heavily rusted and should be completely recoated or replaced.
Delaminating
coating
Horizontal
cracking
Tank cover is
not sealed
Horizontal
cracking
Surface
delamination
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2.7.2 Digester Mixing Systems
Each of the primary digesters (Tank No. 1 and Tank No. 2) have a vertical lance gas mixing system which takes digested gas produced from the digester using a positive displacement blower and then sequentially injects the gas back into the digester via a rotary valve and seven vertical lance assemblies located throughout each digester. The digester mixing system for Tank No. 1 was installed in 1989 when the tank was constructed and the digester mixing system for Tank No. 2 was installed in 1994. Per WWTP staff, both systems work well. However, the equipment and piping are old and are showing heavy rust. The entire mixing system and associated piping should be replaced.
Delaminating
coating
Rust stains from
old anchor points
Tank No. 1
gas blower housing
Tank No. 1
rotary valve
housing
Project Number 2810224-0001977.00 NV5.COM | 26
2.7.3 Sludge Treatment Infrastructure
The sludge heating system, located in the primary control/boiler building east of Digester Tanks No. 2 and No. 3, was upgraded in 2016 with a new heat exchanger/boiler. The heat exchanger is fueled by digested gas from the three digesters and recirculated sludge is heated to a temperature of approximately 95ºF. Per WWTP staff the sludge heating system is in good condition and does not need to be replaced.
There are two active sludge pumps located between Digester Tanks No. 2 and No. 3; one for digested sludge transfer to the belt filter presses and one for sludge recirculation/heating.
The digested sludge pump currently being used is a rotary lobe pump (Vogelsang Model VX136- 210Q). The pump is installed in a temporary setup to replace the old sludge pump that is no longer operable. Per WWTP staff, the lobe pump works very well and is easier to maintain than the old pump. The pump currently draws digested sludge from the bottom of Tank No. 3 and pumps sludge to the belt filter presses for dewatering, but occasionally the piping is reconfigured to pump sludge from either Tank No. 1 or Tank No. 2. The old sludge pump needs to be removed, and a new rotary lobe pump needs to be installed on a permanent equipment pad with permanent piping and electrical equipment. WWTP staff would also like to install a second sludge pump for redundancy.
The current rotary lobe pump would then be stored by the WWTP for backup.
Tank No. 2
gas blower housing
Tank No. 2
rotary valve housing
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The sludge recirculation pump currently being used is a Vaughn chopper pump installed in 2008.
The pump draws sludge from the two primary digester tanks (Tank No. 1 and Tank No. 2) and then pumps sludge through the sludge heat exchanger and back to the primary digester tanks as part of the sludge heating system. Per WWTP staff, the pump is in good condition and does not need to be replaced.
The existing sludge piping and valves between the digestors, between the digestors and the primary clarifiers, and between the digestors and the belt presses consists primarily of 6-inch ductile or castiron pipe. Some of the pipes are exposed and some are buried underground. Most of the piping appears to have been installed in 1989 along with the construction of Digester Tank No. 1.
However, some of the piping connected to Tanks No. 2 and 3 may be original piping when the tanks were constructed in 1957. The exterior condition of the piping varies but is in poor condition overall Old sludge
pump
Temporary
sludge pump
Sludge
recirculation
pump
Project Number 2810224-0001977.00 NV5.COM | 28
and the interior condition is unknown. All the sludge piping, valves, and appurtenances should be completely replaced and piping that is no longer necessary for the current or future operation, including supernatant piping, should be removed.
WWTP staff would also like a new digested sludge bypass line installed from Tank No. 1 to Tank No. 3 (around Tank No. 2) so that the primary digesters (Tank No. 1 and No. 2) can be operated in parallel, which would allow either tank to be taken offline independently. Currently Tank No. 1 can be taken offline independently but Tank No. 2 cannot because digested sludge from Tank No. 1 overflows into Tank No. 2.
2.7.4 Digested Gas Piping and Burner
Digested gas (from all three digester tanks) not used by gas mixing systems is piped to a manifold assembly outside of the primary control/boiler building where some gas is used by the sludge heating system and any remaining gas is piped to the waste gas burner (torch) located east of the digesters across the access road. Like the sludge piping, the piping consists primarily of 6-inch pipe and appears to be ductile iron or steel pipe. Most of the gas piping is exposed except for the underground line running between the boiler building and the waste gas burner. Most of the piping was installed in 1989 with Digester Tank No. 1 or in 1994 with the installation of the gas mixing system for Digester Tank No 2. The exterior condition of the piping varies but is in poor condition overall and the interior condition is unknown. The waste gas burner and all the digested gas piping, valves, and appurtenances should be completely replaced.
Primary sludge piping Digested sludge piping
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2.7.5 Digesters Site
The existing concrete flatwork around all the digesters is in poor condition and should be replaced.
Per the WWTP there is also a storm drain between Tank No. 2 and No. 3 that has collapsed and should also be replaced.
A detailed inspection of the existing stairways and platforms for the digesters was not conducted for this tech memo, but in general they appear to be in fair condition except that the spiral stairway and platforms between Tank No. 2 and No. 3 need to be recoated. WWTP staff have indicated that both stairways interfere with maintenance operations and would like the stairway between Tank No. 1 and No. 2 relocated to provide better forklift access to the gas mixing blower and would like the spiral stairway between Tank No. 2 and No. 3 relocated closer to one of the tanks. WWTP staff also indicated that the spiral stairway between Tank No. 2 and No. 3 could be shortened to only provide access to the lower platform since the upper platform can be accessed from the other stairway.
Digested Gas Waste Gas Burner Piping
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2.8 SOLIDS HANDLING AND DEWATERING
2.8.1 Gravity Belt Thickeners
Waste activated sludge (WAS) at about 1% solids content is pumped from the sludge pump station into a gravity belt thickener (total of two gravity belt thickener units installed: one duty, one standby). Each gravity belt thickener has a maximum hydraulic loading capacity of 560 gpm and a maximum solids loading capacity of 917 lb/hr at design average flow. The gravity belt thickeners are model No. TT-30 manufactured by Phoenix, installed in 1994 and 2008 (GBT No. 1 and No. 2, respectively). WAS is treated with polyacrylamide emulsion polymer (Clarifloc S462) to enhance the removal of water. The gravity belt equipment has the capacity to thicken sludge to 4% solids content.
Thickened sludge is then pumped into the anaerobic primary digester, where it mixes with primary sludge. The sludge pumping is accomplished by two plunger type pumps, which have a maximum capacity of 85 gpm at a total head of 170 ft. Each pump is driven by a 7.5 HP motor.
GBT No.1 shows minor rusting on the joints of the exterior unit and the flocculation chamber. The concrete pad under the mixing tank has minor concrete spalling but otherwise appears to be in good condition. The influent and effluent piping, valves, and appurtenances have delaminated coatings and rusting. Grating around the unit appears to be in good condition. The support beams have delaminated coatings and rusting. The concrete slabs under the GBT No. 1 unit have minor cracking and spalling but otherwise appear to be in good condition. The discharge hopper has rusting on the interior and exterior. GBT No. 1 is at the end of its lifecycle (30 years of operation) and should be replaced, including all piping and appurtenances. The concrete structures are in fair condition and are not necessary to be replaced, however rehabilitation is recommended.
Damaged
concrete
Damaged
concrete
Project Number 2810224-0001977.00 NV5.COM | 31
GBT No. 2 appears to have solids leaking through the seal on the exterior of the unit. There is rusting on the exterior unit and metal beams as well. Grating over the sump is in good condition.
The sump has significant algae growth. The GBT No. 2 discharge hopper has rust on the interior.
The effluent piping and appurtenances have a delaminated coating and rusting. The motor has heavily rusted and has delamination as well. Minor spalling and delamination is evident on the concrete slabs under GBT No. 2 but are otherwise in good condition. GBT No. 2 is reaching the end of its useful life and should be replaced in the next 5 to 10 years. including piping and appurtenances. Rehabilitation is recommended for the concrete slabs when the unit is replaced.
GBT No. 2
Rusting
GBT No. 1
Rusting
Corrosion
Delamination
Project Number 2810224-0001977.00 NV5.COM | 32
The polymer feed system is used for both the GBTs and belt filter presses (BFP). Polymer is stored in totes and are outside and in direct sunlight. Polymer to and from chemical feed pumps presents leaks and should be replaced. Polymer Feed Pumps No. 1 appears to be in good condition. Polymer feed pump No. 2 appears to be in poor condition. The outlet connection from Polymer Feed Pump No. 2 to the hose is damaged and wrapped in tape, with visible leaks.
The shade structure over GBTs No. 1 and No. 2 and TWAS pumps No. 1 and No. 2 is rusted and should be repaired and recoated.
Polymer tote in
direct sunlight
Temporary
piping
Polymer leaks
Polymer
Pump No. 1
Polymer
Pump
No. 2
Air-Release System
Rusting
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2.8.2 TWAS Pumps
The plant has two TWAS pumps located under the shade structure in the solids handling area, TWAS Pumps No. 1 and No. 2. TWAS Pump No. 2 is currently disconnected and set to be replaced in 2025.
TWAS pumps pump thickened sludge from the GBTs to the digester. TWAS Pumps No. 1 and No. 2 were installed in 1994. TWAS Pump No. 1 was replaced with a Vogelsang progressive cavity pump sometime between 2008 and 2025 and is temporarily mounted and in good condition. TWAS Pump No. 1 is the only TWAS pump currently in operation. TWAS Pump No.1 is connected to the GBTs via temporary hose piping. Only one GBT is operated at a time and the temporary piping to TWAS Pump No. 1 is connected to the GBT currently in operation. Until TWAS Pump No. 2 is replaced, the existing TWAS Pump No. 2 will likely remain disconnected. TWAS pump No. 2 is a piston pump set to be replaced with a Vogelsang progressive cavity pump in 2025. The piston pump was used along with Polymer
Pump
No. 2
Leaking and
taping Rusting on
shade structure
Rust
Air Compressor
No. 1
Algae growth in
sump of GBT No. 2
Air Compressor
No. 2
Project Number 2810224-0001977.00 NV5.COM | 34
the existing air-release system. The air-release system, installed in 1994, includes a vertical airrelease tank upstream and downstream of the TWAS pumps, pressure gauges, piping, and appurtenances. Because TWAS Pumps No. 1 and the future TWAS Pump No. 2 are progressive cavity pumps, the air-release system will not be needed.
TWAS Pumps No. 1 and No. 2 should be permanently mounted on concrete pedestals. The airrelease system including tanks, piping, and appurtenances should be removed along with TWAS Pump No. 2. Because the air-release system would no longer be in operation, the air-release system should be removed along with the existing TWAS Pump No. 2.
2.8.3 Sludge Dewatering Belt Filter Presses
The belt filter presses (BFP) take digested sludge from the digesters to further dewater prior to drying in the sludge drying beds. The sludge dewatering system consists of two belt filter presses, one duty and one standby. Belt Press No. 1 (Parkson Model No. MPL-80) was installed in 1994 and is scheduled for replacement in 2025. Belt Press No. 2 (Model No. SER 1000-20 OH) was installed in 2008 for redundancy. Both belt presses are fed polymer from Polymer Feed Pump No. 2 to their respective flocculation/mixing tanks.
Belt Filter Press No. 1 is in poor condition and has reached the end of its useful life cycle. The metal frame, fixtures, and access platforms and ladders show corrosion and coating delamination. The dewatered sludge conveyor shows areas of rust, and the support concrete slab is in poor condition presenting cracks. Concrete support columns for BFP have cracked and spalled, exposing reinforcement rebar. The concrete slab surrounding the belt press, including the curb, has cracks, fractures, spalling, and visible aggregate in several areas. The drain south of the belt press has no grate and is a safety hazard. The grate surrounding the sump has rusted. The influent piping, flocculation tank and motor are rusted and corroded. As part of the replacement of BFP No. 1 in Temporary Mount on
TWAS Pump No. 1
Temporary hose piping to GBTs
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2025, piping, valves, mixing tank, concrete sump and slabs, and auxiliary components should be rehabilitated or replaced.
Belt Press No. 2 is in poor condition. The metal beams for the unit have delaminated coatings and are heavily rusted. All fixtures and appurtenances are rusted with delaminated coatings. The Belt Press
No. 1
Rusting
Damaged
concrete
Corrosion
Delamination
Visible
reinforcement
Spalling and
damaged
concrete
Belt Press
No. 1
Project Number 2810224-0001977.00 NV5.COM | 36
conveyor, motor, and all access ladders are rusted and corroded. The east access ladder has steps with large holes caused by corrosion. The concrete pillars supporting the belt press have delamination, spalling, and solids buildup. The grate surrounding Belt Press No. 2 has rusted. The surrounding concrete of the belt press has rust stains, visible aggregate, and spalling. The flocculation tank, motor, and associated piping and appurtenances are rusted and corroded. Belt Press No. 2, including valves and appurtenances, influent piping and appurtenances, the flocculation tank and motor, the conveyor, and the concrete slabs are all in poor condition and should be replaced.
Belt press No. 1 and No. 2 are in direct sunlight and should be covered by a shade structure Safety hazard
Corrosion and rust
Belt Press No.
2 east
access ladder
Belt Press
No. 2 Rusting
Corrosion
Delamination
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2.8.4 Sludge Drying Bed
The drying bed is a 209-foot by 209-foot 6” thick concrete slab with a single reinforcement mat installed in 2008 and is in good condition. Dewatered sludge from the belt filter presses are conveyed into dump trucks and transported to the onsite sludge drying bed. City staff has indicated that additional sludge drying area would facilitate handling and storage of drying sludge prior to transporting offsite. An additional 209-feet by 209-feet sludge drying bed is recommended be added adjacent to the existing.
2.9 BUILDINGS
Several of the buildings around the plant are in poor condition and need to be refurbished or replaced.
2.9.1 Blower Building
The blower building is a timber structure which was originally constructed in 1988. The building has two rooms, a blower room and an electrical room. The blower room, which contains the blowers described in Section 2.4.2, was modified in 2017 to raise the walls and roof for the replacement blowers.
The electrical room, which contains Motor Control Center (MCC) No. 3 and control panels used for a variety of treatment processes, was not rehabilitated as part of the blower upgrade project in 2017.
The exterior wood siding of the electrical room is in poor condition and should be replaced or refurbished and should be re-painted. The roof of the electrical room is also in poor condition and should be replaced.
The electrical room has some equipment that is no longer in use, some of which was replaced with new equipment in the MCC No. 3A building, a prefabricated metal building in good condition located west of the blower building installed in 1994.
Drying bed
Drying solids
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2.9.2 Main Office Building
The main office building was constructed in 1972. The building has a footprint of approximately 50 feet by 37 feet. The main office building has a control room, laboratory, storage room, bathroom, and janitor closet. The building is in good condition. There have been no modifications to the main office building since it was constructed as part of several plant improvements and expansions since it was originally built. There is insufficient space for the operations staff along with outdated appliances and poor internet connection. As such, WWTP staff has requested the installation of a new office building.
The new building should include a larger control room, a men’s and a separate women’s locker room with showers, a break room with a kitchen, a conference room, a storage room, a bathroom, an operator’s lab, offices for the managerial WWTP staff, and reliable internet connection/Wi-Fi. The new main office building could be located north of the existing office building. The lab in the existing building should remain as is and the rest of the building should be repurposed as the WWTP staff see fit.
MCC No. 3 in
Electrical Room
South wall of
Electrical
Room
Project Number 2810224-0001977.00 NV5.COM | 39
3.0 PRELIMINARY CAPACITY ASSESSMENT
A preliminary capacity assessment was performed to determine the ability of the main treatment processes to meet existing average dry weather flow, maximum daily flow, projected 2045 average dry weather flow. and projected peak wet weather flow conditions. For the purposes of this technical memorandum, the primary clarifiers, aeration basins, and secondary clarifiers are defined as the main treatment processes and were included in the capacity evaluation. This capacity evaluation is a planning level assessment and not a detailed process analysis or model of the treatment process intended to compare the operation of the units under anticipated flow conditions to typical operation parameters for each process.
3.1 DATA ACQUISITION
Flow data for the WWTP was obtained from the City’s Supervisory Control and Data Acquisition (SCADA) system which included instantaneous flow measurements every 15 minutes. The City also provided wastewater characteristics data for the treatment plant and its components through their Discharge Monitoring Report (DMR) monthly monitoring reports. As-builts were obtained from the City for the dimensions of the primary clarifiers, aeration basins, and secondary clarifiers.
The results obtained for the capacity assessment were compared to recommended standards described in industry literature, including Wastewater Engineering: Treatment and Resource Recovery; Fifth Edition by Metcalf & Eddy and Wastewater Treatment Plants: Planning, Design, and Operation by Syed R. Qasim.
3.2 FLOW SCENARIOS
Four flow scenarios were evaluated for the capacity assessment including: 1) existing average dry weather flow (ADWF), 2) existing maximum daily flow, 3) projected future ultimate (2045) average dry weather flow, and 4) projected peak wet weather flow (PWWF). The flows used for each scenario are summarized in Table 1 below.
Table 1 – Flow Scenarios
Existing ADWF
(MGD)
Existing Maximum
Daily Flow (MGD)
Projected 2045
ADWF (MGD) Projected PWWF (MGD)
3.52 5.16 4.68 9
Existing average flow was calculated by averaging influent flow data from the City’s SCADA system between July 13, 2023 and July 13, 2024, which yielded an average flow of approximately 3.52 MGD. The maximum daily flow was obtained from the same period, averaging the flows for each day, and determining the maximum value of average daily flows, estimated at 5.16 MGD. The projected future ultimate ADWF was provided by Dudek as part of the City’s updated master plan based on planned developments, which estimated at 4.68 MGD in 2045. The peak wet weather hourly flow was provided by City staff based on recent wet weather events as measured at the WWTP at 9 MGD, with all lift stations fully operational.
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3.3 MAIN TREATMENT PROCESSES CAPACITY ASESSMENT
The following sections further describe the capacity assessment for each treatment process. The primary clarifiers were assessed for surface loading capacity, detention time, and weir loading capacity. The aeration basins were assessed for hydraulic retention time (HRT) and Biological Oxygen Demand (BOD) Loading. The secondary clarifiers were assessed for surface loading capacity, HRT, and solids loading.
3.3.1 Primary Clarifiers
The capacity of the primary clarifiers was evaluated by calculating the surface loading, detention time, and weir loading for each flow scenario. Surface loading is a standard measurement to determine clarifier capacity, which represents the ratio of the surface area of the clarifier divided by the flow rate. Operating clarifiers at a high surface loading rate can result in solids not adequately settling and not being captured prior to secondary treatment. The hydraulic detention time was also calculated and compared to the recommended operating range. Low detention times can result in unfavorable flow conditions in the clarifier and don’t allow sufficient time for solids to settle. Weirloading rates were calculated for each flow scenario which represent flow volume per length of effluent. Weir loading rates above the recommended range can result in turbulent conditions in the clarifier that could prevent adequate settling of solids.
The primary treatment process consists of two (2) circular clarifiers, each clarifier has a diameter of 65 ft, side water depth (SWD) of 8.75 ft, and a surface area of approximately 3,318 ft2. The surface loading, detention time, and weir loading rate for each flow scenario was calculated and is presented in Table 2 below.
Table 2 – Preliminary Capacity Assessment of Primary Clarifiers Parameter
Recommended
Operating
Range
Existing
ADWF
Existing
Maximum
Daily Flow
Projected
2045 ADWF
Projected
PWWF
Flow Rate
(MGD) - 3.52 5.16 4.68 9
Surface
Loading
(gpd/ft2)
800-1,200 530 777 705 1,356
Detention
Time (hr) 1.5-2.5 2.96 2.02 2.48 1.16
Weir Loading
Rate (gal/ftday)
10,000-
40,000 8,613 12,630 11,459 22,037
As shown above, for the existing ADWF, maximum ADWF, and projected ADWF scenarios, the primary clarifiers operate within or below the recommended operating range for surface loading, detention time, and weir loading rate. However, for the projected peak wet weather flow scenario the surface loading exceeds the recommended range and detention time is lower than the minimum recommended.
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3.3.2 Aeration Basins
The capacity of the aeration basins was evaluated by calculating the hydraulic retention time (HRT) and biological oxygen demand (BOD) loading for each flow scenario. HRT represents the time required for influent to flow through the aeration basins and is calculated by dividing the total volume of the aeration basins by the influent flow rate. Sufficient HRT is required for the biological process to remove organics from the wastewater prior to separating solids in the secondary clarifiers. BOD loading is a measure of the dissolved organic content in the wastewater is calculated by taking the aeration basin influent BOD concentration and multiplying by the flow rate. Higher BOD concentrations in the influent will result in a higher BOD loading to the aeration basins, requiring a larger volume to achieve treatment.
There are six (6) rectangular aeration basins with a combined volume of approximately 193,403 ft3, and their dimensions are shown in Table 3.
Table 3 –Dimensions of Aeration Basins
Dimension Unit Result
Basins 1-4
Length ft 50
Width ft 50
SWD ft 12.05
Volume of Each Basin ft3 30,125
Total Volume ft3 120,500
Basins 5-6
Length ft 55
Width ft 55
SWD ft 12.05
Volume of Each Basin ft3 36,451
Total Volume ft3 72,903
The HRT and BOD loading were calculated based on the dimensions from Table 3 above. The HRT and BOD loading for the aeration basins for each flow scenario are presented in Table 4 below.
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Table 4 – Preliminary Capacity Assessment of Aeration Basins Parameter
Recommended
Operating
Range
Existing
ADWF
Existing
Maximum
Daily Flow
Projected
2045 ADWF
Projected
PWWF
Flow Rate
(MGD) - 3.52 5.16 4.68 9
Hydraulic
Retention
Time (hr)
4 - 8 9.9 6.7 7.4 3.9
BOD Loading
(lbs/1,000 ft3-
day)
20 – 402 28 41 37 71
As shown in the table above, the HRT for the existing ADWF, existing maximum ADWF, and projected ADWF scenarios is within or exceeds the recommended operating range which indicates the aeration basis provide adequate detention time for these flow conditions. For the projected PWWF scenario, the HRT is below the recommended operating range.
The aeration basins operate within the recommended operating range for BOD loading for the existing ADWF and projected 2045 ADWF scenarios. However, under the other two (2) flow conditions, the aeration basins exceed the recommended BOD loading.
3.3.3 Secondary Clarifiers
The capacity of the secondary clarifiers was evaluated by calculating the HRT, surface loading, and solids loading for each flow scenario. HRT represents the time required for influent to flow through the secondary clarifiers and is calculated by dividing the total volume of the clarifiers by the influent flow rate. If the HRT is too low, solids may not be adequately removed impacting effluent quality.
Surface loading is a standard measurement to determine clarifier capacity, which represents the ratio of the surface area of the clarifier divided by the flow rate. Operating clarifiers at a high surface loading rate can result in solids not adequately settling and not being captured prior to UV disinfection. Solids loading represents the quantity of solids in the influent entering the secondary clarifiers. Solids loading is calculated by dividing the quantity of mixed liquor suspended solids (MLSS) in the water, calculated as gallons per day (gpd), by the total surface area of the clarifiers.
There are four (4) secondary clarifiers at the WWTP, each with a diameter of 80 ft and a SWD of 9.95 ft. The secondary clarifiers have a total volume of 120,500 ft3 and a combined surface area of 20,106 ft2.
The HRT, surface loading, and solids loading for the secondary clarifiers for each flow scenario were calculated and presented in Table 5 below.
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Table 5 – Preliminary Capacity Assessment of Secondary Clarifiers Parameter
Recommended
Operating
Range
Existing
ADWF
Existing
Maximum
Daily Flow
Projected
2045 ADWF
Projected
PWWF
Flow Rate
(MGD) - 3.52 5.16 4.68 9
Hydraulic
Retention Time
(hr)
4 – 81 10.2 7.0 7.7 4.0
Surface
Loading
(gpd/ft2)
400-6001 197 257 233 448
Solids Loading
(lbs/ft2-hr) 0.4-1.22 0.1 0.2 0.2 0.4
As shown above, the HRT for the existing ADWF scenario exceeds the recommended operating range. However, this indicates the secondary clarifiers are operating under capacity and can handle the flow scenario. This means at least one (1) secondary clarifier can be taken offline for maintenance during the existing ADWF scenario while still operating within the recommended range.
The HRT is within the recommended operating range for the remaining three flow scenarios.
For the projected PWWF scenario, the surface loading rate is within the recommended range. During the remaining three (3) flow scenarios, the surface loading is less than the recommended range.
However, this indicates the secondary clarifiers are operating under capacity for these flow conditions.
During projected PWWF conditions, the solids loading rate is within the recommended solids loading range. Under the remaining three (3) flow conditions, the solids loading rate is less than the recommended minimum loading rate. However, this indicates the secondary clarifiers are operating under capacity for these flow conditions.
3.4 SUMMARY OF RESULTS AND RECOMMENDATIONS
Table 6 below summarizes the capacity assessment results for the primary clarifiers, aeration basins, and secondary clarifiers for each flow scenario. Values in red are values that exceed the recommended operating range for a given parameter.
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Table 6 – Preliminary Capacity Assessment Results Summary Treatment
Process Parameter Existing ADWF
Existing
Maximum
Daily Flow
Projected
2045 ADWF
Projected
PWWF
-
Flow Rate
(MGD) 3.52 5.16 4.68 9
Primary
Clarifiers
Surface
Loading
(gpd/ft2)
530 777 705 1,356
Detention
Time (hr) 1-2
2.96 2.48 1.16
Weir Loading
Rate (gal/ftday)8,613 12,630 11,459 22,037
Aeration
Basins
Hydraulic
Retention
Time (hr)
9.9 6.7 7.4 3.9
BOD Loading
(lbs/1,000 ft3-
day)
28 41 37 71
Secondary
Clarifiers
Hydraulic
Retention
Time (hr)
10.2 7.0 7.7 4.0
Surface
Loading
(gpd/ft2)
197 257 233 448
Surface
Loading
(gpd/ft2)
0.1 0.2 0.2 0.4
3.4.1 Primary Clarifiers Capacity Alternatives
Since the primary clarifiers do not have capacity to meet projected PWWF hourly scenario (9 mgd), two alternatives were developed to increase the capacity. Alternative A considers adding two clarifiers to match the size of the existing clarifiers (total of four clarifiers) to meet anticipated PWWF conditions. Alternative B considers installing two larger clarifiers to replace the existing clarifiers to provide the required capacity. Both alternatives are described below.
3.4.1.1 Alternative A
Constructing another primary clarifier with the same dimensions as the existing clarifiers would allow the WWTP to operate within the recommended range for surface loading during the peak wet weather flow scenario with a surface loading of approximately 904 gpd/ft2. However, it is recommended that two (2) new primary clarifiers be installed for redundancy purposes and even flow distribution. Two new clarifiers would be installed just west of the existing units with the same dimensions. Based on the conditions of the existing clarifiers, the two existing units would still be
Project Number 2810224-0001977.00 NV5.COM | 45
required to be refurbished (replace equipment, bridge, motors, piping), and the influent structure and piping to be replaced to allow flow splitting to all four units.
3.4.1.2 Alternative B
Alternative B considers replacing the existing clarifiers with two larger units with all new equipment, just west of the existing clarifiers. A new influent structure would be required to split flow to the two new units. Once the new units are operational, the existing clarifiers could be demolished. The existing primary clarifiers would be replaced with two (2) with a diameter of approximately 85 feet and SWD of 12 feet. Having two new units as considered in Alternative B will reduce operation and maintenance cost compared to four units considered in Alternative A.
3.4.1.3 Recommended Alternative
Table 7 below compares the operation of the existing clarifiers, Alternative A and Alternative B.
Table 7 – Characteristics of Existing and Proposed Primary Clarifiers Treatment
Process Parameter Existing ADWF
Existing
Maximum
Daily Flow
Projected
2045 ADWF
Projected
PWWF
-
Flow Rate
(MGD) 3.52 5.16 4.68 9
Existing Primary
Clarifiers
Surface Loading
(gpd/ft2)
530 777 705 1,356
Detention Time
(Hr) 2.96 2.02 2.48 1.16
Weir Loading
Rate (gal/ft-day) 8,613 12,630 11,459 22,037
Alternative A
Surface Loading
(gpd/ft2)
265 389 353 678
Detention Time
(Hr) 5.93 4.04 4.96 2.32
Weir Loading
Rate (gal/ft-day) 4,307 6,315 5,730 11,018
Alternative B
Surface Loading
(gpd/ft2)
310 455 412 793
Detention Time
(Hr) 6.95 4.74 4.79 2.72
Weir Loading
Rate (gal/ft-day) 6,587 9,658 8,763 16,852
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Both Alternatives A and B are able to meet the capacity required for peak hourly wet weather conditions. Alternative B offers several advantages over Alternative A including the ability to complete construction of the two new units with minimal disturbance to the operation of the WWTP, a lower anticipated construction cost, and lower future operation and maintenance costs by operating only two units instead of the four units considered in Alternative A. Based on these advantages, Alternative B to install two larger units to replace the two existing units is recommended.
Project Number 2810224-0001977.00 NV5.COM | 47
4.0 RECOMMENDATIONS
Recommended improvements for the WWTP are listed below to address the condition deficiencies described in Section 2.0 and the capacity deficiencies described in Section 3.0. These improvements are broken down into treatment processes and summarized in Tables 8 through 14.
See the sections below for an overview of these recommended improvements.
CIP project descriptions will be prepared following the Draft WWTP Condition Assessment TM review by City Engineering and Operations staff. Estimated construction value for each CIP project will also be prepared following City’s review.
4.1 HEADWORKS AND PRIMARY TREATMENT
Table 8 - Headworks and Primary Treatment Recommended Improvements Asset
Discipline
Recommended Improvement
Description Justification Type of Issue/ Risk
Mechanical
Bar screen structure - replace
entrance door hardware and
intrusion switch
The door trigger is faulty, and a wooden post
is currently holding the door shut to prevent
the door from opening.
Operational
Failure
Mechanical
Repair floor drain at staircase
landing, bar screen structure
lower-level entrance.
Unclog/repair floor drain to prevent
accumulation of water in the staircase
landing.
Operational
Failure
Mechanical
Replace channel grating
hardware, bar screen
structure.
Grating hardware has corroded and grating
is not secured at influent channel inside the
bar screen structure.
Safety
Structural Install shade structure over
primary sludge pumps
A shade structure should be installed to
protect the primary sludge pumps and
control panel from the elements.
Structural
Failure
Mechanical
Replace all piping that is 6-
inches or less, scum piping,
plug valves, and all other
related valves and
appurtenances in the primary
clarifier gallery
The smaller diameter piping and related
appurtenances have delaminated coatings
and rust. These are in poor condition and
should be replaced.
Operational
Failure
Project Number 2810224-0001977.00 NV5.COM | 48
Asset
Discipline
Recommended Improvement
Description Justification Type of Issue/ Risk
Mechanical
Remove all unused piping
and related appurtenances in
primary clarifier gallery
Remove piping not in use that continues to
deteriorate.
Unused
Equipment
Mechanical
Replace temporary piping
connected to primary sludge
pumps with permanent piping
in primary clarifier gallery
Temporary hoses should be removed, and
properly supported ductile iron piping should
be installed to and from primary sludge
pumps.
Operational
Failure/Safety
Mechanical
Replace the five sluice gates
and metallic safety
components including the
grating, handrail, light pole,
shade structure, and
sampling shed platform in the
primary clarifier gallery
Structural, lighting, and safety components
have reached the end of their useful like,
are heavily rusted and in poor condition. The
condition of the sluice gates is unknown but
are assumed to be in need of replacement
based on age.
Operational
Failure
Structural
and
Mechanical
Recoat and inspect 24-inch
influent line and replace
temporary wooden supports
with permanent concrete or
steel supports
The exterior of the influent line has a
delaminated coating that should be
replaced. The interior condition is unknown
and should be inspected to determine to
replacement is necessary.
Coating
Delamination/
Operational
Failure
Structural
Empty, clean, and have a
structural engineer inspect
the interior and exterior of the
influent distribution structure
to determine proposed
structural improvements.
The interior has not been cleaned or
inspected in recent history and the concrete
walls and concrete roof deck are in poor
condition with large cracks and spalling. The
storm drains between digesters and influent
distribution structure are clogged.
Structural
Failure
Mechanical
Replace existing clarifiers
with two larger clarifiers
(Alternative B)
Replacing the existing clarifiers with larger
ones would solve the above problem while
not adding an operational burden to the
operators by having four clarifiers.
Capacity
Project Number 2810224-0001977.00 NV5.COM | 49
4.2 SECONDARY TREATMENT
4.2.1 Aeration Basins
Table 9 - Aeration Basins Recommended Improvements
Asset
Discipline
Recommended
Improvement Description Justification Type of Issue/ Risk Structural
Empty, clean, and inspect
interior and exterior of each
basin
The interior condition of each basin is
unknown. An inspection should be
conducted to determine if rehabilitation is
necessary.
Structural
Failure
Structural Rehabilitate concrete The exterior concrete of the basin is spalling and cracking and should be rehabilitated.
Structural
Failure
Structural Remove mechanical mixer
concrete pads
The aeration basins no longer use
mechanical mixers, so the concrete
platforms are no longer in use and should
be removed. Concrete is spalling and rebar
is exposed.
Unused
Structure/safety
Mechanical Replace diffusers and
piping
The diffuser heads have reached their
useful service life, occasionally diffuser
heads have detached. Submerged piping
and diffuser heads should be replaced.
Operational
Failure
Mechanical Replace 36 sluice gates
The effluent sluice gates that were not
replaced in 2020 are in poor condition and
should be replaced.
Operational
Failure
4.2.2 Secondary Clarifiers and Ancillary Pumps
Table 10 - Secondary Clarifies Recommended Improvements Asset
Discipline
Recommended Improvement
Description Justification Type of Issue/ Risk
Mechanical
and
Structural
Replace west splitter box and
sluice gates
The west splitter box has large cracks and is
in poor condition. The related sluice gates
should also be replaced.
Operational/
Structural
Failure
Mechanical Replace sluice gates for central
splitter box
The sluice gates on the central splitter box
are in poor condition.
Operational
Failure
Project Number 2810224-0001977.00 NV5.COM | 50
Asset
Discipline
Recommended Improvement
Description Justification Type of Issue/ Risk
Structural Inspect interior and exterior of
plant water pump station
A structural engineer should inspect the
interior and exterior condition of the plant
water pump station after it has been
emptied and cleaned to determine if
replacement or rehabilitation is necessary.
Structural
Failure
Structural Replace roof deck of plant
water pump station
The concrete roof deck has large cracks and
is spalling and is in poor condition.
Structural
and
Operational
Failure
Mechanical Inspect plant water pumps,
piping, and appurtenances
The plant water pumps, piping, and
appurtenances are in fair condition, but
further inspection or replacements should
be considered when replacing the roof deck.
Operational
Failure
Structural
Refurbish concrete for
northwest access hatch of
sludge pump room and
rehabilitate concrete curb
surrounding southwest
aluminum hatch
The northwest access hatch has cracking on
the inner concrete and the concrete curb
surrounding the southwest aluminum hatch
has large cracks on the northwest edge of
the curb.
Structural
Failure
Structural Replace concrete pads for WAS
Pumps No. 1 and No. 2
The concrete pads are in poor condition with
multiple large cracks. The current pads are
too high and should be replaced with shorter
concrete pads.
Structural
Failure
Structural Install cover to the wet well in
the sludge pump room
The wet well not having a cover is a safety
hazard. Injury Risk
Project Number 2810224-0001977.00 NV5.COM | 51
4.3 SOLIDS TREATMENT
4.3.1 Digesters
Table 11 - Digesters Recommended Improvements
Asset
Discipline
Recommended Improvement
Description Justification Type of Issue/ Risk
Structural Reline each digester
The interior of each digester has not been
cleaned, inspected, or lined in recent
history.
Coating
Delamination/
Failure
Structural Replace exterior coating on
Digesters No. 2 and No. 3
The exterior coating is delaminating and
has horizontal cracks visible under the
coating that should be repaired.
Coating
Delamination/
Failure
Structural Replace floating cover on
Digester No. 3
The floating cover is not fully sealed and
has surface delamination and cracking.
Operational
Failure
Mechanical
Remove old digested sludge
pump and replace with new
rotary lobe pump on a
permanent equipment pad.
Add one digested sludge pump.
The old sludge pump is no longer operable.
The temporary sludge pump currently in
use is not permanently mounted and has
temporary hose piping. A permanent
equipment pad, permanent piping, and
electrical equipment should be installed.
Operational
Failure
Mechanical
Replace gas mixing system
with new pump-type mixing
system for Digesters No. 1 and
No. 2
Gas mixing system technology is becoming
obsolete, and replacement components
are no longer available.
Operational
Failure
Mechanical
Replace all sludge piping, plug
valves, and appurtenances
between the digesters and
primary clarifiers and between
the digesters and the belt
presses
The existing sludge piping was installed
from 1957 - 1981 and the exterior of the
piping is in poor condition.
Operational
Failure
Project Number 2810224-0001977.00 NV5.COM | 52
Asset
Discipline
Recommended Improvement
Description Justification Type of Issue/ Risk
Mechanical
Replace all waste gas piping
and appurtenances for each
digester
A majority of the piping was installed in
1981 or in 1994 and the exterior of the
piping and related appurtenances are in
poor condition.
Operational
Failure
Mechanical
Remove unused piping,
including the digester
supernatant piping, for each
digester
There is existing piping that is no longer in
use and will not be used for future
operation.
Unused
Equipment
Structural
Recoat spiral stairway and
remove lower section by
Digester No. 2 and No. 3
The spiral stairway is delaminating and
rusting. The stairway should be relocated
closer to one of the tanks to allow better
forklift access.
Coating
Delamination/
Failure
Structural Relocate stairway by Digester
No. 1 and No. 2
The stairway should be relocated to allow
better forklift access.
Structural
Failure
Structural Recoat the platforms for
Digesters No. 2 and No. 3 The platform has visible delamination.
Coating
Delamination/
Failure
Structural
Replace storm drain between
digesters and primary clarifier
gallery
The storm drain has collapsed.
Injury Risk /
Operational
Failure
Structural Replace concrete flatwork for
each digester
The concrete flatwork is damaged and in
poor condition.
Structural
Failure
Project Number 2810224-0001977.00 NV5.COM | 53
4.3.2 Gravity Belt Thickeners
Table 12 - Gravity Belt Thickener Recommended Improvements Asset
Discipline
Recommended Improvement
Description Justification Type of Issue/ Risk
Mechanical Replace GBTs and related piping
and appurtenances
GBTs No. 1 and No. 2 are at the end of their
useful life. The GBTs and related piping and
appurtenances are in poor condition with
rusting, corrosion, and delamination.
End of
Useful Life
Mechanical Replace air compressors
Air Compressors No. 1 and No. 2 are at the
end of their useful life. They are heavily
rusted and in poor condition.
End of
Useful Life
Structural Rehabilitate concrete slabs
The concrete slabs under GBTs No. 1 and
No. 2 have spalling but are otherwise in fair
condition.
Structural
Failure
Mechanical Replace temporary polymer piping
with permanent piping
All polymer piping is currently temporary
hose piping and appears to have leaks that
are causing a safety hazard.
Operational
Failure/
Injury Risk
Mechanical Replace Polymer Feed Pump No.
2 and outlet connection joint
Polymer feed pump No. 2 is in poor
condition and the related appurtenances are
damaged.
Operational
Failure
Structural
Install shade structure over
polymer totes that reach over the
belt presses and cover polymer
totes with plastic covering
The polymer totes are currently in direct
sunlight so a shade structure would prevent
damage from the elements. Because the
belt presses are located next to the polymer
totes, the structure should extend over the
belt presses as well to shield them from the
elements.
Operational
Failure
Structural Rehabilitate existing shade
structure
The existing shade structure is rusting in
some areas but is otherwise in fair
condition.
Structural
Failure
Mechanical Permanently mount TWAS Pumps
No. 1 and No. 2
TWAS Pump No. 1 is temporarily mounted
and should be mounted on a permanent
concrete pedestal. TWAS Pump No. 2 Is
currently disconnected and should be
permanently mounted when it is replaced in
2025.
Injury Risk/
Operational
Failure
Project Number 2810224-0001977.00 NV5.COM | 54
Asset
Discipline
Recommended Improvement
Description Justification Type of Issue/ Risk
Mechanical
Replace temporary piping for
TWAS Pump No. 1 with
permanent piping and install
permanent piping for TWAS Pump
No. 2
TWAS Pump No. 1 is connected via
temporary hose piping and permanent
piping should be installed for both TWAS
Pumps No. 1 and No. 2.
Injury Risk/
Operational
Failure
4.3.3 Dewatering
Table 13 - Dewatering Recommended Improvements
Asset
Discipline
Recommended Improvement
Description Justification Type of Issue/ Risk
Mechanical Replace Belt Press No. 1
Belt Press No. 2 is in poor condition and is
set to be replaced in 2025. Belt press No. 1
has rusting and corrosion on the piping,
fixtures, and on the unit itself.
Operational
Failure/
End of
Useful Life
Structural Replace concrete pads under
both belt presses
The concrete slabs are damaged, showing
visible reinforcement, spalling, fractured,
and have visible aggregate in several areas.
Structural
Failure
Structural Replace access ladders for both
belt presses
The access ladders are heavily corroded and
have holes in the steps. Injury Risk
Structural Install shade structure over both
belt presses
The belt presses are in direct sunlight and
should be covered by a shade structure to
protect the units from the elements. The
shade structure should not cover the
conveyors.
Operational
Failure
Structural
Install new 209-feet x 209-feet x
6-inch sludge drying bed north of
the existing sludge drying bed
The current sludge drying bed is not large
enough for the current solids load.
Lack of
Capacity
Project Number 2810224-0001977.00 NV5.COM | 55
4.4 OPERATIONS BUILDING IMPROVEMENTS
Table 14 - Buildings Recommended Improvements
Asset
Discipline
Recommended Improvement
Description Justification
Type of
Issue/
Risk
Structural
Construct a new main office
building Northeast of the existing
building.
The existing office building is too small to
accommodate the staff and has one shared
locker room for male and female staff. The
new building should include two locker
rooms, a kitchen/break room, an operations
room, a conference room, an operator's lab,
office spaces for management, a laundry
room, and a storage room. Parking should
be extended to the length of the building.
Operation
Difficulty
Structural
and
Electrical
Remove used electrical
equipment from the blower
building electrical room (MCC No.
3) and refurbish the exterior of
the electrical room
The exterior building and roof are in poor
condition with delaminated paint and
damaged wood paneling. The exterior
building should be refurbished with a new
roof, new wood paneling, and fresh paint. An
electrical engineer should inspect the
electrical equipment to determine which
equipment is unused and can be removed.
Structural
Failure/
Unused
Equipment
Project Number 2810224-0001977.00 NV5.COM
FIGURE 1 – EXISTING PROCESS FLOW DIAGRAM
Delivering Solutions
Improving Lives
Appendix C
Planned Near-Term Developments Table
APPENDIX C
PLANNED NEAR-TERM DEVELOPMENTS
Map ID Development Name Location Description
Proposed
Land Use Proposed Dwelling Units (DU) Total Development Area (acres) Status Projected ADWF (GPD) Assumed Sewer Point of Connection (Trunk Model Manhole ID) 1 Surya Hotel Weakley St north of Wake Ave Commercial 1.30 Planning Review Complete 1,560.00 18-17-1032 Lotus Place Residential Subdivision SEC Ross Ave and Austin Rd Low Density Residential 561 160.00 Pre-Application 98,175.00 20-11-1303 Courtyard Villas SEC W Orange Ave and Glenwood Rd Low Density Residential 53 19.43 Pre-Application 9,275.00 20-11-1304 Spear & 6th Street Apartments NEC Spears Ave and 6th St High-Medium Density Residential 288 14.11 Planning Review 33,864.00 17-14-1145 CR&R Transfer Station Ross Ave, approximately 250 ft east of Montenegro Way
Industrial 8.75 Planning Review 1,750.00 20-15-123
6 Town Center Industrial Park - Residential NWC Cruickshank Dr and N 8th St Medium Density Residential 102 11.71 Planning Review 17,850.00 25-13-99 Town Center Industrial Park - Industrial NWC Cruickshank Dr and N 8th St Industrial 33.00 Planning Review 6,600.00 25-13-100 7 Willowbend Residential Subdivision West side of S 4th St, approximately 600 ft south of W Horne Rd
Low Density Residential 134 37.04 Planning Review 23,450.00 17-13-149 8 Parkview Residential Subdivision East side of S 8th St, approximately 700 ft south of W Horne Rd
Low Density Residential 114 26.05 Planning Review 19,950.00 18-13-127 9 Town Center Self Storage SWC Cruickshank Dr and N 8th St Commercial 7.74 Building/Grading Permit Review 6,192.00 25-13-100 10 Restaurant 751 E Danenberg Dr Commercial 0.11 Planning Review Complete 21.00 17-17-10411 Town Center Industrial Condominiums SWC Cruickshank Dr and N 8th St Industrial 0.79 Planning Review Complete 157.00 25-13-10012 Food 4 Less Gas Station 2420 Cottonwood Dr Commercial 1.92 Planning Review Complete 1,536.00 25-12-10613 Dogwood Bar 411 E Aurora Dr Commercial 0.10 Planning Review Complete 82.40 20-15-14114 Police Station 150 N 11 St Institution 1.07 Under construction 853.60 21-13-10215 Dunkin Donuts 3063 N Imperial Ave Commercial 0.70 Under construction 561.52 25-12-11716 Dairy Queen 3065 N Imperial Ave Commercial 1.05 Completed 838.59 25-12-117 17 Town Center Village IV NWC Bradshaw Ave and N 8th St High-Medium Density Residential 180 11.59 Under construction 27,816.00 24-13-10218 Penske 502 E Main St Commercial 3.41 Completed 2,729.24 22-15-106 19 Vo Medical Center 1699 N Imperial Ave Commercial 4.87 Completed 3,894.16 23-12-11220 Maverik Gas Station 1402 S Dogwood Rd Commercial 6.74 Completed 5,395.41 20-15-14121 Jersey Mike's / The UPS Store 1002 N Imperial Ave Commercial 1.17 Completed 934.10 23-12-11322 Lotus Ranch West of S La Brucherie Rd and south of I-8 Medium Density Residential 609 100.76 Under construction 106,575.00 18-11-11023 California Highway Patrol Station 2802 S 4th St Institution 1.02 Under construction 816.00 17-14-11224 El Dorado Family Apartments 1805 N 8th St High-Medium Density Residential 136 5.99 Under construction 14,376.00 23-13-10125 U-Haul Expansion 1745 S 4th St Commercial 6.94 Completed 5,552.01 18-14-10026 La Brucherie and Main Apartments 303 S La Brucherie Rd High-Medium Density Residential 177 11.90 Planning Review Complete 28,554.16 21-11-13927 Gomez Park
East side of S Hope St, approximately 300 ft south of E Hamilton Ave Park 7.15 In design 1,429.44 20-15-141 28 Buena Vista Park SWC Manuel Ortiz Ave and S 8th St Park 11.33 Under construction 2,266.24 16-12-100 29 Home 2 Suites 3105 S Dogwood Rd Commercial 2.90 Under construction 3,481.02 17-17-10430 Residence Inn Hotel 3409 S Dogwood Rd Commercial 3.99 Building/Grading Permit Review 4,790.11 17-17-10431 Jamba Juice and Wing Stop 1497 Adams Ave Commercial 0.69 Completed 554.09 23-14-13332 Valley Pediatric 1446 W Pico Ave Commercial 1.77 Completed 1,416.38 23-13-10133 Jacaranda Gardens I Apartments 1625 N Waterman Ave Residential 96 4.36 Completed 10,469.20 23-12-11234 Bark Park NEC Park Ave and N 7th St Park 1.65 Completed 329.78 22-14-11335 Gas Station with Carwash 3003 S 4th St Commercial 0.14 Planning Review 110.40 17-14-11236 Hyundai Dealership 2202 Merrill Center Dr Commercial 0.42 Building/Grading Review 504.00 17-13-14937 One Stop Meats La Carniceria 2033 S 4th St Commercial 0.03 Planning Review Complete 25.60 18-14-11038 Dogwood and Villa Annexation South of E Villa Ave, east of N Dogwood St, and west of Cooley Rd
Industrial 320.00 Planning Review 32,000.00 23-17-101
39 Dutch Bros Coffee 740 N Imperial Ave Commercial 0.06 Planning Review 66.00 22-12-10340 Innercare Medical Facility E Danenberg Dr, approximately 275 ft east of IV Commons Dr
Commercial 0.49 Planning Review Complete 591.60 17-13-121 41 Big J Fencing new warehouse with offices 336 Main St Commercial 0.19 Planning Review Complete 152.00 21-15-115 42 4:13 Fitness Center 1531 W Main St Commercial 0.43 Under construction 516.00 21-12-128 43 Villa Ocotillo Apartments 1080 Adams Ave High Density Residential 38 0.75 Planning Review Completed 1,797.60 23-14-133 44 Maresca Apartments 718 Adams Ave High-Medium Density Residential 8 0.42 Planning Review 1,003.58 22-14-11345 El Centro Shopping Center SEC Wake Ave and Imperial Ave Commercial 3.56 Planning Review 4,272.00 17-13-12746 Wal-Mart Fuel Station 2150 N Waterman Ave Commercial 2.99 Planning Review 2,389.73 25-12-10847 Town Center Single-Family Residential Tract NWC Cruickshank Dr and N 8th St Medium Density Residential 102 13.10 Planning Review 17,850.00 25-13-103 48 Zadeh Self Storage NEC Cruickshank Dr and N 8th St Commercial 0.05 Planning Review 36.80 25-13-106 49 Humane Society S Hope St, approximately 650 ft north of E Ross Ave Commercial 0.18 Planning Review 144.00 20-15-141 50 Raising Canes 2297 N Imperial Ave Commercial 1.31 Planning Review 1,047.60 25-12-102 51 Cross Rd and Villa Ave -- Septic to Sewer Cross Road and Villa Ave neighborhood Low Density Residential 32 68.27 Planning Review 5,600.00 23-14-10952 Ross and Dogwood -- Industrial Development Ross Ave and Dogwood Industrial 483.65 Planning Review 92,507.35 20-15-141 A-1
Appendix D
City of El Centro Temporary Sewer Flow
Metering Report
4820 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
ElCentro.Dudek.TFM.CA24
City of El Centro Temporary Sewer Flow
Metering
Final Report Submitted to Dudek
April 16, 2025
City of El Centro Temporary Flow Metering
Prepared For:
Elizabeth Caliva, P.E.
Dudek
2280 Historic Decatur Rd, Ste 200
San Diego, CA 92106
Prepared By:
ADS, LLC
4820 Mercury St #C
San Diego, CA 92111
Thursday, 06 March 2025 to Wednesday, 19 March 2025
April 16, 2025
Elizabeth Caliva, P.E.
Dudek
2280 Historic Decatur Rd, Ste 200
San Diego, CA 92106
SUBJECT: City of El Centro Temporary Sewer Metering
Dear Elizabeth Caliva,
ADS is pleased to submit the report for the City of El Centro Temporary Sewer Flow Metering, completed on behalf of Dudek.
The metering was conducted at ten (10) locations. The study was conducted during the period of Thursday, 06 March 2025 to Wednesday, 19 March 2025.
The report contains depth, velocity, and quantity hydrographs as well as daily long tables for the metering period. An Excel file containing depth, quantity, and velocity entities for the monitoring location in 5-minute format has been provided.
In addition, we would be happy to further explain any details about the report that may seem unclear. Should you have any questions or comments, you may contact the Project Manager, Ashura Aby Takanohara at 256.929.0075.
It has been our pleasure to be of service to you in the performance of this project. Thank you for choosing ADS products and services to meet your flow monitoring needs.
Sincerely,
ADS ENVIRONMENTAL SERVICES
Chris Kong
Hydraulic Data Analyst
11
Introduction
Dudek entered into an agreement with ADS Environmental Services to conduct flow monitoring at (9) nine flow metering locations, and (1) one rain gauge location in El Centro. The study was scheduled for a period of (14) fourteen days. Once in place, the flow monitoring equipment was to be used to measure depth, velocity, and to quantify flows. The objective of this study was to confirm flows for sewer masterplan and hydraulic model calibration.
Project Scope
The scope of this study involved using a flow monitor to quantify wastewater flow at the designated locations for the study period. Specifically, the study included the following key components. • Investigate the proposed flow-monitoring site for adequate hydraulic conditions • Flow monitor installation
• Flow monitor confirmations and data collections
• Flow data analysis
Additionally, temporary rain gauge monitors were used to measure and record rainfall at the designated locations. Specifically, the study involved the following key components.
• Investigate the proposed rain gauge sites for sufficient exposure and security • Rain Gauge installations
• Manually confirming rain gauge tipping bucket operation and date collections • Rain data analysis
Equipment installation was completed on February 27th, 2025. The monitoring period began on March 3rd, 2025, and was completed on March 19th, 2025. Upon completion of the study, equipment was removed from the system.
Flow Monitoring Equipment
The ADS Triton+ monitor was selected for this project. This flow monitor is an area velocity flow monitor that uses both the Continuity and Manning's equations to measure flow.
The ADS Triton+ monitor consists of data acquisition sensors and a battery-powered microcomputer. The microcomputer includes a processor unit, data storage, and an on-board clock to control and synchronize the sensor recordings. The monitor was programmed to acquire and store depth of flow and velocity readings at 5-minute intervals.
Scope and Methodology
22
The Triton+ monitor features cross-checking using multiple technologies in each sensor for continuous running of comparisons and tolerances. The Triton+ monitor can support two (2) sets of sensors. The sensor option used for this project was:
The Peak Combo Sensor installed at the bottom of the pipe includes three types of data acquisition technologies The up looking ultrasonic depth uses sound waves from two independent transceivers to measure the distance from the sensor upward toward the flow surface; applying the speed of sound in the water and the temperature measured by sensor to calculate depth.
The pressure depth is calculated by using a piezo-resistive crystal to determine the difference between hydrostatic and atmospheric pressure. The pressure sensor is temperature compensated and vented to the atmosphere through a desiccant filled breather tube.
To obtain peak velocity, the sensor sends an ultrasonic signal at an angle upward through the widest cross-section of the oncoming flow. The signal is reflected by suspended particles, air bubbles, or organic matter with a frequency shift proportional to the velocity of the reflecting objects. The reflected signal is received by the sensor and processed using digital spectrum analysis to determine the peak flow velocity.
Installation
Installation of flow monitoring equipment typically proceeds in four steps. First, the site is investigated for safety and to determine physical and hydraulic suitability for the flow monitoring equipment. Second, the equipment is physically installed at the selected location. Third, the monitor is tested to assure proper operation of the velocity and depth of flow sensors and verify that the monitor clock is operational and synchronized to the master computer clock. Fourth, the depth and velocity sensors are confirmed and line confirmations are performed.
In pipes up to 42 inches in diameter, the sensors were mounted on expandable stainless-steel rings, inserted at least a foot upstream into influent pipes and tightened against the inside walls of the pipes. Influent pipe installations reduce the influences of turbulence and backwater often caused by changes in channel geometry in manholes. 33
Data Collection, Confirmation, and Quality Assurance
Data collects were done remotely via wireless connect on a weekly basis. As needed, during the monitoring period, field crews visit each monitoring location to verify proper monitor operation and document field conditions. The following quality assurance steps are taken to assure the integrity of the collected data:
Measure power supplies: monitors were powered by dry cell battery packs. Voltages were recorded and battery packs replaced, as necessary. Separate batteries provided back-up power to memory allowing primary batteries to be replaced without loss of data.
Clock synchronization: Field crews synchronized monitor clocks to master clocks.
Confirm depth and velocity readings: Field crews descended into meter manholes to manually measure depths and velocities and compare the meter readings to confirm that they agreed. The site met the criteria for confirmation for depth and velocity unless noted otherwise in the site commentary section. They also measured silt levels, if any, in the inverts of the pipes. Silt areas were subtracted from flow areas to compute true areas of flow.
Confirm average velocities through cross-sectional velocity profiles: Since ADS velocity sensors measure peak velocity, field crews collected cross-sectional velocity profiles in order to develop a relationship between peak and average velocity in lines that meet the hydraulic criteria.
Upload and Review Data: Data collected from the monitors were uploaded and reviewed by a Data Analyst for completeness, outliers and deviations in the flow patterns, which indicate system anomalies or equipment failure. 44
Rainfall Logging Equipment
The ADS RainAlert III monitor was selected for this project. This monitor provides rainfall data acquisition and intelligent alarming to support wastewater capital improvement.
The ADS RainAlert III monitor measures rainfall using a tipping bucket containing a funnel and a small tipping mechanism that can collect a specific amount of rainfall. Once the tipping mechanism is full it empties and records that a tip has occurred.
Typically, each tip is equivalent to 0.01 inches (or 0.2mm) of rainfall. The monitor records the number of tips that occur over each 5-minute interval to calculate discrete rainfall amounts for each of those 5-minute intervals.
Installation
Installation of rainfall logging equipment typically proceeds in five steps. First, investigating and selecting the appropriate location to install the tipping bucket and monitor. Second, installing the Sun Shield involves properly placing the sun shield and securing it to an appropriate structure or surface, or mounting it to a pole, as applicable. Third, involves mounting the tipping bucket on the sun shield at the designated rainfall collection location and connecting the wires from the monitor to the tipping bucket. Fourth, involves testing and adjusting the tipping bucket and internal tipping mechanism to ensure it accurately measures rainfall amounts. The final step involves installing the monitor at the appropriate location.
Flow Quantification Methods
There are two main equations used to measure open channel flow: the Continuity Equation and the Manning Equation. The Continuity Equation, which is considered the most accurate, can be used if both depth of flow and velocity are available. In cases where velocity measurements are not available or not practical to obtain, the Manning Equation can be used to estimate velocity from the depth data based on certain physical characteristics of the pipe (i.e. the slope and roughness of the pipe being measured). However, the Manning equation assumes uniform, steady flow hydraulic conditions with non-varying roughness, which are typically invalid assumptions in most sanitary sewers. The Continuity Equation was used exclusively for this study. 55
Continuity Equation
The Continuity Equation states that the flow quantity (Q) is equal to the wetted area (A) multiplied by the average velocity (V) of the flow.
Q = A * V
This equation is applicable in a variety of conditions including backwater, surcharge, and reverse flow.
Data Analysis and Presentation
Data Analysis
A flow monitor is typically programmed to collect data at 5-minute intervals throughout the monitoring period. The monitor stores raw data consisting of (1) the ultrasonic depth, (2) the peak velocity and (3) the pressure depth. The data is imported into ADS's proprietary software and is examined by a data analyst to verify its integrity. The data analyst also reviews the daily field reports and site visit records to identify conditions that would affect the collected data.
Velocity profiles and the line confirmation data developed by the field personnel are reviewed by the data analyst to identify inconsistencies and verify data integrity. Velocity profiles are reviewed and an average to peak velocity ratio is calculated for the site. This ratio is used in converting the peak velocity measured by the sensor to the average velocity used in the Continuity equation. The data analyst selects which depth sensor entity will be used to calculate the final depth information. Silt levels present at each site visit are reviewed and representative silt levels established.
Occasionally the velocity sensor's performance may be compromised resulting in invalid readings sporadically during the monitoring period. This is generally caused by excessive debris (silt) blocking the sensor's crystals, shallow flows (~< 1") that may drop below the top of the sensor or very clear flows lacking the particles needed to measure rate. In order to use the Continuity equation to quantify the flow during these periods, a Data Analyst and/or Engineer will use the site's historical pipe curve (depth vs. velocity) data along with valid field confirmations to reconstitute and replace the false velocity recordings with expected velocity readings for a given historical depth along the curve.
Selections for the above parameters can be constant or can change during the monitoring period. While the data analysis process is described in a linear manner, it often requires an iterative approach to accurately complete.
Data Presentation
This type of flow monitoring project generates a large volume of data. To facilitate review of the data, results have been provided in graphical and tabular formats. The flow data is presented graphically in the form of scattergraphs and hydrographs.
Hydrographs are based on 15-minute data. Tables are provided in daily average format. These tables show the flow rate for each day, along with the daily minimum and maximums, the times they were observed, the total daily flow, and total flow for the month (or monitoring period). The following explanation of terms may aid in interpretation of the flow data table and hydrograph.
DFINAL - Final calculated depth measurement (in inches) QFINAL - Final calculated flow rate (in MGD)
VFINAL - Final calculated flow velocity (in feet per second) RAIN – Final calculated rainfall (in inches)
REPORT TOTAL - Total volume of flow recorded for the indicated time period (in MG) 66
EC_FM01_23-12-122
Site Commentary
SITE INFORMATION
OBSERVATIONS
Average flow depth, velocity, and quantity data observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025, along with observed minimum and maximum data, are provided in the following table.
Site operated under freeflow conditions for the duration of the study. This location is downstream from FM06, a review of balancing shows no complications.
Observed Flow Conditions
Item DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total
MG)
Average 8.05 2.22 0.961
Minimum 4.91 1.82 0.471
Maximum 10.66 2.61 1.308
Min Time 03/17/2025 4:10:00 AM 03/11/2025 4:20:00 AM 03/16/2025 4:35:00 AM Max Time 03/11/2025 9:15:00 PM 03/17/2025 1:00:00 AM 03/11/2025 10:00:00 PM Based upon the quality and consistency of the observed flow depth and velocity data, the Continuity equation was used to calculate flow rate and quantities during the monitoring period.
Values in the Observed Flow Conditions are based off the five minute average.
Values in the graphical reports are based off the fifteen minute average.
Values in the tabular report are based off the five minute average.
DATA UPTIME
Data uptime observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025 is provided in the following table:
Percent Uptime
DFINAL (in) 100
VFINAL (ft/s) 100
QFINAL (MGD - Total MG) 100
Pipe Elliptical (15 in H x 14.88 in W)
Silt 0.00 (in)
77
Latitude: 32.8026276
Longitude: 115.5701255
Site Sketch Profile View or Photo
Sensor Shot
23124.11.325
Additional Site Info. / Comments:
ADS Project Name:
ADS Project Number:
ElCentro.Dudek.TFM.CA24
Wireless
Pipe Material
Antenna Location
Communication Information:
Manhole Pick / Vent Hole
No
Vitrified Clay Pipe
vented Normal
Fair
Active Drop Connections Air Quality:
Communication Type
High H2S
26'' 54''
Manhole Cover Manhole Frame
Pipe Condition:
Manhole Material:
Manhole Diameter (Approx.):
Manhole Depth (Approx. FT): Manhole Configuration
Brick Fair
197"
Manhole Condition:
Upstream 0-5 FT Manhole
Sensors / Devices:
Installation Confirmation:
Manhole Opening Diameter (in)
Silt Type
Hydraulic Comments:
0''
Single
0.25"
Manhole / Pipe Information:
Pressure Sensor Range (psi)
Confirmation Time:
Sandy / Gravel
Peak Combo (CS4)
Pipe Size (HxW)
0 Downlooker Physical Offset (in) Measurement Confidence (in) NA
Peak Velocity (fps)
Silt (in)
4:19:00 AM 15.00'' x 14.88''
Small waves with medium depth and moderate velocity.
0 - 5 psi
Depth of Flow (Wet DOF) (in) Range (Air DOF) (in)
5.63''
Velocity Sensor Offset (in)
1.67 fps
Installation Information
Circular
Monitor Series
Monitor Location:
Pulse Standard Ring and Crank
Manhole #
Installation Date:
Pipe Size (H x W)
Topside / Area Photo
Wednesday, February 26, 2025
Access
Temporary
15.00'' x 14.88''
Traffic
23-12-122 Residential/Commercial
Map
Installation Type:
Monitoring Location (Sensors):
EC_FM01_23-12-122
TRITON+ VZ
System Characteristics
Location Type
Pipe Shape DRIVE
ElCentro.Dudek.TFM.CA24
Drive Light
Site Access Details:
Site Address /Location:
23124.11.325
1198 N Imperial Ave, El Centro, CA 92243
Flow Monitoring
Site Report
South Inlet
(sensor location)
North Outlet
88
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Hydrograph Report
EC_FM01_23-12-122
99
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Scattergraph Report
EC_FM01_23-12-122
1010
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Daily Tabular Report
03/06/2025 00:00 - 03/19/2025 23:59
EC_FM01_23-12-122Pipe: Elliptical (15 in H x 14.88 in W), Silt0.00 in DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total MG)
Date Time Min Time Max Avg Time Min Time Max Avg Time Min Time Max Avg Total 03/06/2025 04:30 5.62 21:00 9.54 8.05 02:55 2.04 06:00 2.40 2.25 04:50 0.570 22:00 1.190 0.967 0.967 03/07/2025 04:25 5.37 11:35 9.78 8.02 02:10 1.92 23:45 2.46 2.23 04:55 0.516 11:15 1.201 0.959 0.959 03/08/2025 05:35 5.55 12:50 10.01 7.76 03:25 1.98 01:20 2.40 2.22 03:25 0.540 12:55 1.250 0.916 0.916 03/09/2025 06:30 5.37 22:00 10.00 8.03 06:35 1.88 00:10 2.29 2.15 06:35 0.477 13:45 1.241 0.930 0.930 03/10/2025 04:45 5.41 21:40 10.27 8.24 04:15 1.87 07:05 2.31 2.16 04:15 0.481 21:40 1.264 0.964 0.964 03/11/2025 05:40 5.88 21:15 10.66 8.47 04:20 1.82 16:05 2.32 2.11 04:20 0.541 22:00 1.308 0.974 0.974 03/12/2025 04:40 5.82 22:25 10.44 8.44 04:15 1.89 08:30 2.29 2.16 04:15 0.539 22:20 1.293 0.989 0.989 03/13/2025 03:30 5.93 22:30 9.86 8.22 04:40 1.85 23:30 2.39 2.18 03:40 0.538 22:05 1.211 0.971 0.971 03/14/2025 04:35 5.34 13:20 9.20 7.83 04:05 1.90 07:15 2.42 2.24 04:05 0.479 13:40 1.155 0.937 0.937 03/15/2025 04:30 4.99 12:25 10.39 7.70 05:50 2.04 23:15 2.47 2.28 05:50 0.503 12:25 1.288 0.927 0.927 03/16/2025 05:45 5.02 11:55 9.86 7.73 04:35 1.95 23:55 2.59 2.27 04:35 0.471 12:00 1.264 0.935 0.935 03/17/2025 04:10 4.91 21:30 10.21 8.02 04:00 2.11 01:00 2.61 2.37 04:00 0.477 21:15 1.300 1.017 1.017 03/18/2025 05:15 5.27 21:40 10.35 8.12 05:40 1.89 00:50 2.52 2.27 05:00 0.477 22:15 1.300 0.990 0.990 03/19/2025 04:25 5.31 22:20 9.84 8.05 05:55 1.86 07:35 2.40 2.22 05:05 0.482 22:25 1.236 0.962 0.961 03/06/2025 00:00 - 03/19/2025 23:59
DFINAL
(in)
VFINAL
(ft/s)
QFINAL
(MGD -
Total MG)
Total 13.437
Average 8.05 2.22 0.960
1111
EC_FM02_22-14-120
Site Commentary
SITE INFORMATION
OBSERVATIONS
Average flow depth, velocity, and quantity data observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025, along with observed minimum and maximum data, are provided in the following table.
Site operated under freeflow conditions for the duration of the study. This location is downstream from FM03, FM04, and FM05, a review of balancing shows no complications.
Observed Flow Conditions
Item DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total
MG)
Average 3.30 5.22 0.844
Minimum 2.11 4.78 0.398
Maximum 4.38 5.51 1.323
Min Time 03/09/2025 6:45:00 AM 03/17/2025 5:15:00 AM 03/09/2025 6:45:00 AM Max Time 03/13/2025 11:45:00 AM 03/13/2025 11:45:00 AM 03/13/2025 11:45:00 AM Based upon the quality and consistency of the observed flow depth and velocity data, the Continuity equation was used to calculate flow rate and quantities during the monitoring period.
Values in the Observed Flow Conditions are based off the five minute average.
Values in the graphical reports are based off the fifteen minute average.
Values in the tabular report are based off the five minute average.
DATA UPTIME
Data uptime observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025 is provided in the following table:
Percent Uptime
DFINAL (in) 100
VFINAL (ft/s) 100
QFINAL (MGD - Total MG) 100
Pipe Elliptical (22.25 in H x 22 in W)
Silt 0.00 (in)
1212
Latitude: 32.7966037
Longitude: 115.5527602
Site Sketch Profile View or Photo
Sensor Shot
EC_FM02_22-14-120
TRITON+ VZ
System Characteristics
Location Type
Pipe Shape DRIVE
ElCentro.Dudek.TFM.CA24
Drive Light
Site Access Details:
Site Address /Location:
23124.11.325
402 Adams Ave, El Centro, CA 92243
Flow Monitoring
Site Report
Installation Information
Circular
Monitor Series
Monitor Location:
Pulse Standard Ring and Crank
Manhole #
Installation Date:
Pipe Size (H x W)
Topside / Area Photo
Wednesday, February 26, 2025
Access
Temporary
22.25'' x 22.00''
Traffic
22-14-120 Residential/Commercial
Map
Installation Type:
Monitoring Location (Sensors):
Peak Combo (CS4)
Pipe Size (HxW)
0 Downlooker Physical Offset (in) Measurement Confidence (in) NA
Peak Velocity (fps)
Silt (in)
2:50:00 AM 22.25'' x 22.00''
Smooth shallow depths and fast velocity.
0 - 5 psi
Depth of Flow (Wet DOF) (in) Range (Air DOF) (in)
2.75''
Velocity Sensor Offset (in)
5.45 fps
Upstream 0-5 FT Manhole
Sensors / Devices:
Installation Confirmation:
Manhole Opening Diameter (in)
Silt Type
Hydraulic Comments:
0''
Single
0.25"
Manhole / Pipe Information:
Pressure Sensor Range (psi)
Confirmation Time:
Sandy / Gravel
26'' 54''
Manhole Cover Manhole Frame
Pipe Condition:
Manhole Material:
Manhole Diameter (Approx.):
Manhole Depth (Approx. FT): Manhole Configuration
Unknown Fair
205"
Manhole Condition:
23124.11.325
Additional Site Info. / Comments:
ADS Project Name:
ADS Project Number:
ElCentro.Dudek.TFM.CA24
Wireless
Pipe Material
Antenna Location
Communication Information:
Manhole Pick / Vent Hole
No
Concrete
vented Normal
Fair
Active Drop Connections Air Quality:
Communication Type
High H2S
1313
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Hydrograph Report
EC_FM02_22-14-120
14
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Scattergraph Report
EC_FM02_22-14-120
15
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Daily Tabular Report
03/06/2025 00:00 - 03/19/2025 23:59
EC_FM02_22-14-120Pipe: Elliptical (22.25 in H x 22 in W), Silt0.00 in DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total MG)
Date Time Min Time Max Avg Time Min Time Max Avg Time Min Time Max Avg Total 03/06/2025 05:05 2.25 21:15 3.80 3.32 05:25 4.86 21:25 5.40 5.22 05:05 0.445 21:15 1.054 0.851 0.851 03/07/2025 05:00 2.22 11:00 3.77 3.25 04:35 4.84 11:50 5.40 5.21 04:35 0.434 11:00 1.043 0.825 0.825 03/08/2025 05:45 2.14 13:05 4.04 3.16 05:45 4.82 12:45 5.45 5.18 05:45 0.408 13:05 1.167 0.790 0.790 03/09/2025 06:45 2.11 14:05 3.75 3.15 06:45 4.80 13:55 5.40 5.18 06:45 0.398 14:05 1.035 0.787 0.787 03/10/2025 05:55 2.20 22:10 4.07 3.35 05:30 4.84 21:15 5.47 5.24 05:30 0.428 22:10 1.179 0.869 0.869 03/11/2025 04:45 2.25 21:15 4.16 3.36 05:30 4.85 21:15 5.48 5.25 04:45 0.443 21:15 1.224 0.873 0.873 03/12/2025 05:40 2.21 21:00 3.84 3.32 04:45 4.86 20:35 5.43 5.23 05:40 0.432 21:00 1.077 0.857 0.857 03/13/2025 05:15 2.24 11:45 4.38 3.39 05:40 4.85 11:45 5.51 5.25 05:15 0.442 11:45 1.323 0.882 0.882 03/14/2025 04:25 2.27 12:50 3.85 3.31 06:00 4.86 12:45 5.45 5.22 04:25 0.448 12:50 1.088 0.849 0.849 03/15/2025 05:55 2.32 13:45 3.99 3.25 05:05 4.85 14:35 5.44 5.20 05:55 0.464 13:45 1.141 0.823 0.823 03/16/2025 05:45 2.24 12:30 3.80 3.25 06:10 4.85 13:20 5.43 5.21 05:45 0.440 12:30 1.061 0.827 0.827 03/17/2025 05:15 2.21 11:40 3.90 3.33 05:15 4.78 12:05 5.44 5.24 05:15 0.426 11:40 1.095 0.862 0.862 03/18/2025 05:00 2.24 22:05 4.04 3.32 05:00 4.84 21:55 5.45 5.23 05:00 0.440 22:05 1.164 0.856 0.856 03/19/2025 04:35 2.28 22:00 3.92 3.33 04:55 4.85 18:30 5.41 5.24 04:55 0.453 22:00 1.107 0.861 0.860 03/06/2025 00:00 - 03/19/2025 23:59
DFINAL
(in)
VFINAL
(ft/s)
QFINAL
(MGD -
Total MG)
Total 11.810
Average 3.29 5.22 0.844
16
EC_FM03_21-15-101
Site Commentary
SITE INFORMATION
OBSERVATIONS
Average flow depth, velocity, and quantity data observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025, along with observed minimum and maximum data, are provided in the following table.
Site operated under freeflow conditions for the duration of the study. This location is upstream of FM02.
Observed Flow Conditions
Item DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total
MG)
Average 4.99 0.50 0.090
Minimum 3.99 0.26 0.035
Maximum 6.15 0.74 0.153
Min Time 03/17/2025 3:10:00 AM 03/17/2025 3:55:00 AM 03/17/2025 3:55:00 AM Max Time 03/06/2025 1:55:00 PM 03/11/2025 4:25:00 AM 03/12/2025 8:30:00 PM Based upon the quality and consistency of the observed flow depth and velocity data, the Continuity equation was used to calculate flow rate and quantities during the monitoring period.
Values in the Observed Flow Conditions are based off the five minute average.
Values in the graphical reports are based off the fifteen minute average.
Values in the tabular report are based off the five minute average.
DATA UPTIME
Data uptime observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025 is provided in the following table:
Percent Uptime
DFINAL (in) 100
VFINAL (ft/s) 100
QFINAL (MGD - Total MG) 100
Pipe Elliptical (10.38 in H x 10.25 in W)
Silt 0.00 (in)
17
Latitude: 32.7942515
Longitude: 115.5487587
Site Sketch Profile View or Photo
Sensor Shot
23124.11.325
Additional Site Info. / Comments:
ADS Project Name:
ADS Project Number:
ElCentro.Dudek.TFM.CA24
Wireless
Pipe Material
Antenna Location
Communication Information:
Manhole Pick / Vent Hole
No
Vitrified Clay Pipe
Unbolted Normal
Good
Active Drop Connections
The flow possibly has oil that seems to be from a car and there is a strong smell of gasoline in the manhole.
Air Quality:
Communication Type
Normal
26'' 54''
Manhole Cover Manhole Frame
Pipe Condition:
Manhole Material:
Manhole Diameter (Approx.):
Manhole Depth (Approx. FT): Manhole Configuration
Brick Fair
107"
Manhole Condition:
Upstream 0-5 FT Manhole
Sensors / Devices:
Installation Confirmation:
Manhole Opening Diameter (in)
Silt Type
Hydraulic Comments:
0''
Single
0.25"
Manhole / Pipe Information:
Pressure Sensor Range (psi)
Confirmation Time:
Sandy / Gravel
Peak Combo (CS4)
Pipe Size (HxW)
0 Downlooker Physical Offset (in) Measurement Confidence (in) NA
Peak Velocity (fps)
Silt (in)
6:51:00 AM 10.38'' x 10.25''
Smooth flow with moderate depth and slow velocity. Flow felt thick from oil like material. 0 - 5 psi
Depth of Flow (Wet DOF) (in) Range (Air DOF) (in)
4.63''
Velocity Sensor Offset (in)
0.49 Installation Information
Circular
Monitor Series
Monitor Location:
Pulse Standard Ring and Crank
Manhole #
Installation Date:
Pipe Size (H x W)
Topside / Area Photo
Tuesday, February 25, 2025
Access
Temporary
10.38'' x 10.25''
Traffic
21-15-101 Residential/Commercial
Map
Installation Type:
Monitoring Location (Sensors):
EC_FM03_21-15-101
TRITON+ VZ
System Characteristics
Location Type
Pipe Shape DRIVE
ElCentro.Dudek.TFM.CA24
Drive Light
Site Access Details:
Site Address /Location:
23124.11.325
271 N 3rd St, El Centro, CA 92243
Flow Monitoring
Site Report
South Inlet
( Sensor Location)
North Outlet
18
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Hydrograph Report
EC_FM03_21-15-101
19
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Scattergraph Report
EC_FM03_21-15-101
20
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Daily Tabular Report
03/06/2025 00:00 - 03/19/2025 23:59
EC_FM03_21-15-101Pipe: Elliptical (10.38 in H x 10.25 in W), Silt0.00 in DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total MG)
Date Time Min Time Max Avg Time Min Time Max Avg Time Min Time Max Avg Total 03/06/2025 03:45 4.36 13:55 6.15 5.26 03:55 0.32 06:35 0.69 0.48 03:55 0.048 14:00 0.144 0.092 0.092 03/07/2025 04:35 4.32 12:30 5.83 5.11 04:45 0.32 10:30 0.71 0.49 04:45 0.047 18:05 0.140 0.091 0.091 03/08/2025 06:15 4.25 13:30 5.79 4.99 04:55 0.33 21:55 0.73 0.49 04:55 0.048 12:05 0.138 0.088 0.088 03/09/2025 05:40 4.09 10:30 5.87 5.09 05:30 0.32 17:55 0.67 0.48 05:30 0.047 15:20 0.135 0.089 0.089 03/10/2025 06:05 4.24 15:35 6.05 5.22 05:15 0.31 02:40 0.72 0.50 05:15 0.045 15:35 0.137 0.096 0.096 03/11/2025 04:35 4.17 13:45 5.68 5.09 04:40 0.29 04:25 0.74 0.49 04:40 0.041 08:40 0.134 0.091 0.091 03/12/2025 03:00 4.19 21:30 5.82 5.15 05:15 0.30 20:20 0.73 0.54 05:15 0.043 20:30 0.153 0.103 0.103 03/13/2025 03:25 4.20 10:55 5.88 5.07 03:30 0.35 17:10 0.73 0.53 03:30 0.050 10:55 0.151 0.098 0.098 03/14/2025 04:40 4.03 09:05 5.71 4.89 04:00 0.29 12:35 0.71 0.52 04:00 0.040 12:35 0.147 0.093 0.093 03/15/2025 05:15 4.21 13:10 5.65 4.81 03:35 0.34 09:00 0.69 0.50 03:35 0.048 12:15 0.141 0.086 0.086 03/16/2025 04:35 4.19 15:40 5.44 4.70 05:35 0.31 02:25 0.72 0.48 05:35 0.044 15:40 0.136 0.080 0.080 03/17/2025 03:10 3.99 11:35 5.45 4.77 03:55 0.26 09:40 0.70 0.49 03:55 0.035 09:40 0.126 0.085 0.085 03/18/2025 04:35 4.04 21:50 5.83 4.86 04:45 0.28 14:00 0.70 0.49 04:45 0.038 14:00 0.132 0.085 0.085 03/19/2025 04:25 4.02 10:05 5.55 4.84 03:50 0.28 13:30 0.70 0.48 03:15 0.039 13:30 0.128 0.083 0.083 03/06/2025 00:00 - 03/19/2025 23:59
DFINAL
(in)
VFINAL
(ft/s)
QFINAL
(MGD -
Total MG)
Total 1.260
Average 4.99 0.50 0.090
21
EC_FM04_22-15-116
Site Commentary
SITE INFORMATION
OBSERVATIONS
Average flow depth, velocity, and quantity data observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025, along with observed minimum and maximum data, are provided in the following table.
Site operated under freeflow conditions for the duration of the study. This location is upstream of FM02 Observed Flow Conditions
Item DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total
MG)
Average 9.26 0.69 0.373
Minimum 7.56 0.38 0.167
Maximum 11.80 1.05 0.744
Min Time 03/18/2025 5:50:00 AM 03/19/2025 5:05:00 AM 03/19/2025 5:05:00 AM Max Time 03/13/2025 11:30:00 AM 03/13/2025 11:30:00 AM 03/13/2025 11:30:00 AM Based upon the quality and consistency of the observed flow depth and velocity data, the Continuity equation was used to calculate flow rate and quantities during the monitoring period.
Values in the Observed Flow Conditions are based off the five minute average.
Values in the graphical reports are based off the fifteen minute average.
Values in the tabular report are based off the five minute average.
DATA UPTIME
Data uptime observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025 is provided in the following table:
Percent Uptime
DFINAL (in) 100
VFINAL (ft/s) 100
QFINAL (MGD - Total MG) 100
Pipe Elliptical (16.88 in H x 16 in W)
Silt 0.00 (in)
22
Latitude: 32.7949301
Longitude: 115.5473569
Site Sketch Profile View or Photo
Sensor Shot
23124.11.325
Additional Site Info. / Comments:
ADS Project Name:
ADS Project Number:
ElCentro.Dudek.TFM.CA24
Wireless
Pipe Material
Antenna Location
Communication Information:
Manhole Pick / Vent Hole
No
Vitrified Clay Pipe
Unbolted Normal
Good
Active Drop Connections Air Quality:
Communication Type
Normal
26'' 54''
Manhole Cover Manhole Frame
Pipe Condition:
Manhole Material:
Manhole Diameter (Approx.):
Manhole Depth (Approx. FT): Manhole Configuration
Concrete Fair
224"
Manhole Condition:
Upstream 0-5 FT Manhole
Sensors / Devices:
Installation Confirmation:
Manhole Opening Diameter (in)
Silt Type
Hydraulic Comments:
2.63''
Single
0.25"
Manhole / Pipe Information:
Pressure Sensor Range (psi)
Confirmation Time:
Sandy / Gravel
Peak Combo (CS4)
Pipe Size (HxW)
0 Downlooker Physical Offset (in) Measurement Confidence (in) NA
Peak Velocity (fps)
Silt (in)
11:56:00 AM 16.88'' x 16.00''
Smooth flow deep depth and slow velocity. Concrete obstruction in the middle of the pipe 0 - 5 psi
Depth of Flow (Wet DOF) (in) Range (Air DOF) (in)
10.00''
Velocity Sensor Offset (in)
0.8 Installation Information
Elliptical
Monitor Series
Monitor Location:
Pulse Standard Ring and Crank
Manhole #
Installation Date:
Pipe Size (H x W)
Topside / Area Photo
Tuesday, February 25, 2025
Access
Temporary
16.88'' x 16.00''
Traffic
22-15-116 Commercial
Map
Installation Type:
Monitoring Location (Sensors):
EC_FM04_22-15-116
TRITON+ VZ
System Characteristics
Location Type
Pipe Shape DRIVE
ElCentro.Dudek.TFM.CA24
Drive Medium
Site Access Details:
Site Address /Location:
23124.11.325
256 W Commercial Ave, El Centro, CA 92243
Flow Monitoring
Site Report
East Inlet
( Sensor Location)
West Outlet
23
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Hydrograph Report
EC_FM04_22-15-116
24
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Scattergraph Report
EC_FM04_22-15-116
25
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Daily Tabular Report
03/06/2025 00:00 - 03/19/2025 23:59
EC_FM04_22-15-116Pipe: Elliptical (16.88 in H x 16 in W), Silt0.00 in DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total MG)
Date Time Min Time Max Avg Time Min Time Max Avg Time Min Time Max Avg Total 03/06/2025 06:10 7.88 22:00 10.48 9.34 06:00 0.49 22:00 0.86 0.71 06:00 0.213 22:00 0.532 0.389 0.389 03/07/2025 05:30 7.87 16:50 10.39 9.23 04:50 0.49 11:10 0.86 0.71 04:50 0.218 16:50 0.521 0.384 0.384 03/08/2025 06:10 7.57 12:30 10.53 8.99 05:40 0.46 12:30 0.80 0.62 05:40 0.193 12:30 0.497 0.325 0.325 03/09/2025 08:00 7.66 22:10 10.55 9.06 06:15 0.40 22:05 0.85 0.62 06:15 0.171 22:05 0.531 0.329 0.329 03/10/2025 05:55 7.69 21:50 10.81 9.46 06:15 0.47 21:55 0.91 0.70 06:15 0.198 21:55 0.588 0.393 0.393 03/11/2025 05:35 7.86 19:50 11.11 9.44 05:35 0.48 19:45 0.94 0.74 05:35 0.208 19:50 0.624 0.412 0.412 03/12/2025 05:45 8.00 22:05 10.56 9.44 05:25 0.49 22:05 0.91 0.74 05:25 0.219 22:05 0.568 0.409 0.409 03/13/2025 05:20 7.71 11:30 11.80 9.42 05:25 0.50 11:30 1.05 0.77 05:25 0.212 11:30 0.744 0.426 0.426 03/14/2025 05:40 7.77 15:30 10.53 9.22 05:40 0.49 15:30 0.92 0.74 05:40 0.211 15:30 0.575 0.397 0.397 03/15/2025 06:00 7.79 13:15 10.50 9.08 08:00 0.48 13:15 0.87 0.67 05:40 0.209 13:15 0.541 0.356 0.356 03/16/2025 06:10 7.75 14:10 10.38 9.15 06:30 0.43 14:10 0.78 0.62 06:30 0.184 14:10 0.476 0.332 0.332 03/17/2025 05:05 7.71 18:45 10.73 9.29 03:55 0.41 18:45 0.89 0.66 03:55 0.181 18:45 0.568 0.361 0.361 03/18/2025 05:50 7.56 22:55 10.90 9.21 07:30 0.40 23:00 0.92 0.64 07:30 0.180 23:00 0.597 0.347 0.347 03/19/2025 05:45 7.77 22:30 10.60 9.29 05:05 0.38 22:30 0.87 0.65 05:05 0.167 22:30 0.547 0.355 0.355 03/06/2025 00:00 - 03/19/2025 23:59
DFINAL
(in)
VFINAL
(ft/s)
QFINAL
(MGD -
Total MG)
Total 5.216
Average 9.26 0.69 0.373
26
EC_FM05_21-14-145
Site Commentary
SITE INFORMATION
OBSERVATIONS
Average flow depth, velocity, and quantity data observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025, along with observed minimum and maximum data, are provided in the following table.
Site operated under freeflow conditions for the duration of the study. This location is upstream of FM02 Observed Flow Conditions
Item DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total
MG)
Average 4.18 1.10 0.198
Minimum 2.78 0.69 0.068
Maximum 5.30 1.41 0.300
Min Time 03/14/2025 3:40:00 AM 03/16/2025 4:55:00 AM 03/07/2025 3:50:00 AM Max Time 03/10/2025 8:55:00 PM 03/12/2025 7:55:00 AM 03/18/2025 10:10:00 PM Based upon the quality and consistency of the observed flow depth and velocity data, the Continuity equation was used to calculate flow rate and quantities during the monitoring period.
Values in the Observed Flow Conditions are based off the five minute average.
Values in the graphical reports are based off the fifteen minute average.
Values in the tabular report are based off the five minute average.
DATA UPTIME
Data uptime observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025 is provided in the following table:
Percent Uptime
DFINAL (in) 100
VFINAL (ft/s) 100
QFINAL (MGD - Total MG) 100
Pipe Elliptical (14.5 in H x 14.25 in W)
Silt 0.00 (in)
27
Latitude: 32.7901562
Longitude: 115.5525879
Site Sketch Profile View or Photo
Sensor Shot
EC_FM05_21-14-145
TRITON+ VZ
System Characteristics
Location Type
Pipe Shape DRIVE
ElCentro.Dudek.TFM.CA24
Drive Heavy
Site Access Details:
Site Address /Location:
23124.11.325
315 S 4th St, El Centro, CA 92243
Flow Monitoring
Site Report
Installation Information
Circular
Monitor Series
Monitor Location:
Pulse Standard Ring and Crank
Manhole #
Installation Date:
Pipe Size (H x W)
Topside / Area Photo
Thursday, February 27, 2025
Access
Temporary
14.50'' x 14.25''
Traffic
21-14-145 Residential/Commercial
Map
Installation Type:
Monitoring Location (Sensors):
Peak Combo (CS4)
Pipe Size (HxW)
0 Downlooker Physical Offset (in) Measurement Confidence (in) NA
Peak Velocity (fps)
Silt (in)
3:08:00 AM 14.50'' x 14.25''
Smooth flow medium depth and slow velocity.
0 - 15 psi
Depth of Flow (Wet DOF) (in) Range (Air DOF) (in)
3.13''
Velocity Sensor Offset (in)
0.89 fps
Upstream 0-5 FT Manhole
Sensors / Devices:
Installation Confirmation:
Manhole Opening Diameter (in)
Silt Type
Hydraulic Comments:
0''
Single
0.25"
Manhole / Pipe Information:
Pressure Sensor Range (psi)
Confirmation Time:
Sandy / Gravel
26'' 54''
Manhole Cover Manhole Frame
Pipe Condition:
Manhole Material:
Manhole Diameter (Approx.):
Manhole Depth (Approx. FT): Manhole Configuration
Vitrified Clay Pipe Fair
123"
Manhole Condition:
23124.11.325
Additional Site Info. / Comments:
ADS Project Name:
ADS Project Number:
ElCentro.Dudek.TFM.CA24
Wireless
Pipe Material
Antenna Location
Communication Information:
Manhole Pick / Vent Hole
No
Vitrified Clay Pipe
Unbolted Normal
Fair
Active Drop Connections
Moved location 1 manhole downstream to MH 21-14-145 due to traffic hazard.
Air Quality:
Communication Type
Normal
South Inlet
(Sensor Location)
North Outlet
28
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Hydrograph Report
EC_FM05_21-14-145
29
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Scattergraph Report
EC_FM05_21-14-145
30
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Daily Tabular Report
03/06/2025 00:00 - 03/19/2025 23:59
EC_FM05_21-14-145Pipe: Elliptical (14.5 in H x 14.25 in W), Silt0.00 in DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total MG)
Date Time Min Time Max Avg Time Min Time Max Avg Time Min Time Max Avg Total 03/06/2025 03:55 2.93 07:50 4.99 4.24 04:00 0.75 20:55 1.30 1.10 04:00 0.079 20:55 0.284 0.202 0.202 03/07/2025 04:05 2.81 08:10 4.91 4.17 03:50 0.69 16:50 1.24 1.06 03:50 0.068 08:05 0.269 0.190 0.190 03/08/2025 05:00 2.92 12:10 5.10 4.17 05:25 0.69 14:30 1.33 1.05 05:25 0.073 12:10 0.294 0.190 0.190 03/09/2025 06:05 2.88 14:00 5.06 4.16 06:10 0.69 13:35 1.31 1.06 06:10 0.071 13:35 0.295 0.192 0.192 03/10/2025 04:15 3.03 20:55 5.30 4.24 04:10 0.78 22:10 1.34 1.10 04:10 0.086 21:00 0.298 0.201 0.201 03/11/2025 03:55 2.99 21:45 5.07 4.18 03:15 0.74 19:35 1.32 1.13 03:15 0.082 21:40 0.297 0.204 0.204 03/12/2025 04:00 2.85 20:45 5.03 4.19 04:05 0.75 07:55 1.41 1.11 04:05 0.076 20:45 0.293 0.200 0.200 03/13/2025 03:40 2.93 21:35 4.90 4.14 03:55 0.81 08:15 1.31 1.14 03:55 0.086 21:35 0.283 0.203 0.203 03/14/2025 03:40 2.78 11:45 4.82 4.12 03:50 0.77 14:35 1.41 1.11 03:50 0.076 14:35 0.285 0.197 0.197 03/15/2025 04:45 2.98 11:55 4.99 4.10 05:20 0.73 11:50 1.32 1.09 05:20 0.079 11:55 0.293 0.192 0.192 03/16/2025 04:50 2.87 20:35 5.12 4.16 04:55 0.69 19:35 1.33 1.09 04:55 0.070 20:20 0.297 0.199 0.199 03/17/2025 04:25 2.96 20:50 4.97 4.19 04:15 0.73 18:40 1.34 1.09 04:15 0.078 20:10 0.281 0.197 0.197 03/18/2025 04:30 2.81 22:10 5.11 4.16 04:30 0.72 22:10 1.31 1.09 04:30 0.072 22:10 0.300 0.195 0.195 03/19/2025 03:50 2.79 21:50 5.01 4.19 04:05 0.74 21:35 1.33 1.11 04:05 0.072 21:35 0.296 0.201 0.201 03/06/2025 00:00 - 03/19/2025 23:59
DFINAL
(in)
VFINAL
(ft/s)
QFINAL
(MGD -
Total MG)
Total 2.764
Average 4.17 1.10 0.197
31
EC_FM06_21-12-135
Site Commentary
SITE INFORMATION
OBSERVATIONS
Average flow depth, velocity, and quantity data observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025, along with observed minimum and maximum data, are provided in the following table.
Site operated under freeflow conditions for the duration of the study. This location is upstream of FM01.
Observed Flow Conditions
Item DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total
MG)
Average 8.92 1.37 0.538
Minimum 6.61 0.86 0.239
Maximum 10.57 1.76 0.790
Min Time 03/16/2025 5:45:00 AM 03/16/2025 6:15:00 AM 03/16/2025 6:15:00 AM Max Time 03/11/2025 8:55:00 PM 03/12/2025 9:50:00 PM 03/12/2025 9:50:00 PM Based upon the quality and consistency of the observed flow depth and velocity data, the Continuity equation was used to calculate flow rate and quantities during the monitoring period.
Values in the Observed Flow Conditions are based off the five minute average.
Values in the graphical reports are based off the fifteen minute average.
Values in the tabular report are based off the five minute average.
DATA UPTIME
Data uptime observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025 is provided in the following table:
Percent Uptime
DFINAL (in) 100
VFINAL (ft/s) 100
QFINAL (MGD - Total MG) 100
Pipe Elliptical (11.63 in H x 11.5 in W)
Silt 0.00 (in)
32
Latitude: 32.7906171
Longitude: 115.5698898
Site Sketch Profile View or Photo
Sensor Shot
23124.11.325
Additional Site Info. / Comments:
ADS Project Name:
ADS Project Number:
ElCentro.Dudek.TFM.CA24
Wireless
Pipe Material
Antenna Location
Communication Information:
Manhole Pick / Vent Hole
No
PVC
Unbolted Normal
Good
Active Drop Connections Air Quality:
Communication Type
Normal
26'' 54''
Manhole Cover Manhole Frame
Pipe Condition:
Manhole Material:
Manhole Diameter (Approx.):
Manhole Depth (Approx. FT): Manhole Configuration
Unknown Good
142"
Manhole Condition:
Upstream 0-5 FT Manhole
Sensors / Devices:
Installation Confirmation:
Manhole Opening Diameter (in)
Silt Type
Hydraulic Comments:
0''
Single
0.25"
Manhole / Pipe Information:
Pressure Sensor Range (psi)
Confirmation Time:
Sandy / Gravel
Peak Combo (CS4)
Pipe Size (HxW)
0 Downlooker Physical Offset (in) Measurement Confidence (in) NA
Peak Velocity (fps)
Silt (in)
1:24:00 AM 11.63'' x 11.50''
Smooth deep flows with moderate velocity.
0 - 15 psi
Depth of Flow (Wet DOF) (in) Range (Air DOF) (in)
7.25''
Velocity Sensor Offset (in)
1.23 fps
Installation Information
Circular
Monitor Series
Monitor Location:
Pulse Standard Ring and Crank
Manhole #
Installation Date:
Pipe Size (H x W)
Topside / Area Photo
Thursday, February 27, 2025
Access
Temporary
11.63'' x 11.50''
Traffic
21-12-135 Residential/Commercial
Map
Installation Type:
Monitoring Location (Sensors):
EC_FM06_21-12-135
TRITON+ VZ
System Characteristics
Location Type
Pipe Shape DRIVE
ElCentro.Dudek.TFM.CA24
Drive Heavy
Site Access Details:
Site Address /Location:
23124.11.325
242 S Imperial Ave, El Centro, CA 92243
Flow Monitoring
Site Report
South Inlet
( Sensor Location)
North Outlet
33
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Hydrograph Report
EC_FM06_21-12-135
34
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Scattergraph Report
EC_FM06_21-12-135
35
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Daily Tabular Report
03/06/2025 00:00 - 03/19/2025 23:59
EC_FM06_21-12-135Pipe: Elliptical (11.63 in H x 11.5 in W), Silt0.00 in DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total MG)
Date Time Min Time Max Avg Time Min Time Max Avg Time Min Time Max Avg Total 03/06/2025 04:35 7.51 08:00 9.99 9.04 05:45 1.03 20:20 1.67 1.39 04:35 0.337 20:20 0.711 0.552 0.552 03/07/2025 04:05 6.83 11:05 10.06 8.86 03:50 0.90 11:30 1.67 1.36 03:50 0.259 11:30 0.713 0.532 0.532 03/08/2025 05:05 6.85 12:35 10.24 8.66 04:40 0.90 12:35 1.65 1.31 04:40 0.261 12:35 0.727 0.499 0.499 03/09/2025 06:35 6.86 13:10 10.18 8.83 07:30 0.90 13:00 1.67 1.34 06:25 0.262 13:05 0.728 0.523 0.523 03/10/2025 04:15 6.75 21:50 10.41 9.02 03:20 0.90 21:10 1.71 1.39 04:15 0.256 21:10 0.760 0.552 0.552 03/11/2025 04:25 7.02 20:55 10.57 9.06 04:20 0.89 21:00 1.73 1.39 04:20 0.264 20:55 0.779 0.554 0.554 03/12/2025 04:35 6.97 21:55 10.56 9.02 04:30 0.90 21:50 1.76 1.39 04:30 0.266 21:50 0.790 0.552 0.552 03/13/2025 04:30 6.98 22:00 10.28 8.96 04:25 0.89 11:25 1.70 1.37 04:25 0.262 11:25 0.750 0.542 0.542 03/14/2025 04:10 6.89 10:55 9.87 8.80 04:00 0.87 10:45 1.58 1.33 04:00 0.253 10:45 0.675 0.517 0.517 03/15/2025 04:35 6.87 11:50 10.26 8.71 06:10 0.88 11:55 1.69 1.32 06:10 0.256 11:55 0.745 0.507 0.507 03/16/2025 05:45 6.61 21:55 10.22 8.80 06:15 0.86 11:45 1.66 1.34 06:15 0.239 11:45 0.728 0.524 0.524 03/17/2025 04:40 6.86 21:35 10.45 9.06 04:40 0.91 21:30 1.75 1.40 04:40 0.262 21:25 0.780 0.559 0.559 03/18/2025 04:35 6.84 21:45 10.36 9.05 04:35 0.90 21:40 1.72 1.39 04:35 0.260 21:40 0.761 0.557 0.557 03/19/2025 04:20 6.80 22:00 10.27 8.97 04:30 0.91 21:55 1.70 1.38 04:30 0.261 22:00 0.749 0.548 0.548 03/06/2025 00:00 - 03/19/2025 23:59
DFINAL
(in)
VFINAL
(ft/s)
QFINAL
(MGD -
Total MG)
Total 7.520
Average 8.92 1.36 0.537
36
EC_FM07_21-11-103
Site Commentary
SITE INFORMATION
OBSERVATIONS
Average flow depth, velocity, and quantity data observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025, along with observed minimum and maximum data, are provided in the following table.
Flow at this site is influenced by a nearby pumpstation. This location is downstream from FM08, a review of balancing shows no complications.
Observed Flow Conditions
Item DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total
MG)
Average 5.96 1.66 0.764
Minimum 3.01 0.76 0.120
Maximum 8.42 2.41 1.573
Min Time 03/15/2025 5:50:00 AM 03/08/2025 6:40:00 AM 03/08/2025 6:40:00 AM Max Time 03/09/2025 10:35:00 PM 03/17/2025 8:30:00 PM 03/09/2025 10:35:00 PM Based upon the quality and consistency of the observed flow depth and velocity data, the Continuity equation was used to calculate flow rate and quantities during the monitoring period.
Values in the Observed Flow Conditions are based off the five minute average.
Values in the graphical reports are based off the fifteen minute average.
Values in the tabular report are based off the five minute average.
DATA UPTIME
Data uptime observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025 is provided in the following table:
Percent Uptime
DFINAL (in) 100
VFINAL (ft/s) 100
QFINAL (MGD - Total MG) 100
Pipe Elliptical (27.25 in H x 27.13 in W)
Silt 0.00 (in)
37
Latitude: 32.7955651
Longitude: -115.5787039
Site Sketch Profile View or Photo
Sensor Shot
23124.11.325
Additional Site Info. / Comments:
ADS Project Name:
ADS Project Number:
ElCentro.Dudek.TFM.CA24
Wireless
Pipe Material
Antenna Location
Communication Information:
Manhole Pick / Vent Hole
No
Vitrified Clay Pipe
vented Normal
Fair
Active Drop Connections
Moved location 1 manhole downstream to MH 22-11-103 due to traffic hazard. Manhole ID on site name is incorrect.
Air Quality:
Communication Type
High H2S
26'' 54''
Manhole Cover Manhole Frame
Pipe Condition:
Manhole Material:
Manhole Diameter (Approx.):
Manhole Depth (Approx. FT): Manhole Configuration
Brick Fair
174"
Manhole Condition:
Upstream 0-5 FT Manhole
Sensors / Devices:
Installation Confirmation:
Manhole Opening Diameter (in)
Silt Type
Hydraulic Comments:
0''
Single
0.25"
Manhole / Pipe Information:
Pressure Sensor Range (psi)
Confirmation Time:
Sandy / Gravel
Peak Combo (CS4)
Pipe Size (HxW)
0 Downlooker Physical Offset (in) Measurement Confidence (in) NA
Peak Velocity (fps)
Silt (in)
10:53:00 AM 27.25'' x 27.13''
Smooth flow with medium depth and velocity. Pumpstation influenced. 0 - 15 psi
Depth of Flow (Wet DOF) (in) Range (Air DOF) (in)
7.00''
Velocity Sensor Offset (in)
1.44 fps
Installation Information
Circular
Monitor Series
Monitor Location:
Pulse Standard Ring and Crank
Manhole #
Installation Date:
Pipe Size (H x W)
Topside / Area Photo
Wednesday, February 26, 2025
Access
Temporary
27.25'' x 27.13''
Traffic
22-11-103 Residential/Commercial
Map
Installation Type:
Monitoring Location (Sensors):
EC_FM07_21-11-103
TRITON+ VZ
System Characteristics
Location Type
Pipe Shape DRIVE
ElCentro.Dudek.TFM.CA24
Drive Medium
Site Access Details:
Site Address /Location:
23124.11.325
2003 W Adams Ave, El Centro, CA 92243
Flow Monitoring
Site Report
38
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Hydrograph Report
EC_FM07_21-11-103
39
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Scattergraph Report
EC_FM07_21-11-103
40
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Daily Tabular Report
03/06/2025 00:00 - 03/19/2025 23:59
EC_FM07_21-11-103Pipe: Elliptical (27.25 in H x 27.13 in W), Silt0.00 in DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total MG)
Date Time Min Time Max Avg Time Min Time Max Avg Time Min Time Max Avg Total 03/06/2025 05:00 3.13 12:35 8.21 5.94 05:00 0.80 18:00 2.33 1.64 05:00 0.133 22:10 1.469 0.752 0.752 03/07/2025 04:05 3.07 19:25 8.11 5.93 04:05 0.78 00:05 2.23 1.65 04:05 0.126 19:25 1.435 0.754 0.754 03/08/2025 06:40 3.03 13:50 8.28 5.93 06:40 0.76 14:50 2.22 1.65 06:40 0.120 13:50 1.487 0.753 0.753 03/09/2025 06:55 3.13 22:35 8.42 5.95 06:55 0.83 22:35 2.29 1.66 06:55 0.138 22:35 1.573 0.769 0.769 03/10/2025 04:35 3.19 22:40 8.33 6.00 04:35 0.84 22:35 2.30 1.66 04:35 0.142 22:40 1.548 0.773 0.773 03/11/2025 04:35 3.13 21:10 8.40 5.99 04:35 0.81 21:10 2.28 1.66 04:35 0.136 21:10 1.554 0.766 0.766 03/12/2025 05:40 3.20 22:40 8.36 6.00 05:35 0.81 08:50 2.23 1.64 05:35 0.139 22:40 1.512 0.763 0.763 03/13/2025 04:40 3.03 22:00 8.17 5.99 04:40 0.78 22:00 2.27 1.67 04:40 0.124 22:00 1.492 0.769 0.769 03/14/2025 05:10 3.05 19:00 7.99 5.83 05:10 0.81 21:05 2.27 1.65 05:10 0.129 19:00 1.424 0.735 0.735 03/15/2025 05:50 3.01 12:35 8.20 5.88 05:50 0.77 12:35 2.27 1.65 05:50 0.121 12:35 1.496 0.752 0.752 03/16/2025 06:50 3.17 22:20 8.29 5.95 06:50 0.83 12:35 2.33 1.68 06:50 0.140 22:20 1.533 0.775 0.775 03/17/2025 04:05 3.17 21:35 8.34 6.01 04:05 0.84 20:30 2.41 1.68 04:05 0.142 21:35 1.565 0.782 0.782 03/18/2025 04:20 3.14 22:30 8.30 5.94 04:20 0.82 22:30 2.28 1.66 04:20 0.137 22:30 1.534 0.760 0.760 03/19/2025 04:20 3.10 22:45 8.35 6.01 04:20 0.81 22:40 2.27 1.67 04:20 0.132 12:10 1.517 0.776 0.776 03/06/2025 00:00 - 03/19/2025 23:59
DFINAL
(in)
VFINAL
(ft/s)
QFINAL
(MGD -
Total MG)
Total 10.679
Average 5.95 1.66 0.763
41
EC_FM08_UNK
Site Commentary
SITE INFORMATION
OBSERVATIONS
Average flow depth, velocity, and quantity data observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025, along with observed minimum and maximum data, are provided in the following table.
Site operated under freeflow conditions for the duration of the study. This location is upstream of FM07.
Observed Flow Conditions
Item DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total
MG)
Average 5.30 0.67 0.190
Minimum 3.67 0.20 0.034
Maximum 8.19 1.05 0.438
Min Time 03/06/2025 4:45:00 AM 03/17/2025 3:25:00 AM 03/17/2025 3:25:00 AM Max Time 03/19/2025 10:45:00 AM 03/06/2025 9:10:00 AM 03/06/2025 9:10:00 AM Based upon the quality and consistency of the observed flow depth and velocity data, the Continuity equation was used to calculate flow rate and quantities during the monitoring period.
Values in the Observed Flow Conditions are based off the five minute average.
Values in the graphical reports are based off the fifteen minute average.
Values in the tabular report are based off the five minute average.
DATA UPTIME
Data uptime observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025 is provided in the following table:
Percent Uptime
DFINAL (in) 100
VFINAL (ft/s) 100
QFINAL (MGD - Total MG) 100
Pipe Elliptical (17.88 in H x 17.75 in W)
Silt 0.00 (in)
42
Latitude: 32.76336358
Longitude: 115.5693255
Site Sketch Profile View or Photo
Sensor Shot
22843.22.325
Additional Site Info. / Comments:
ADS Project Name:
ADS Project Number:
ElCentro.Dudek.TFM.CA24
Wireless
Pipe Material
Antenna Location
Communication Information:
Manhole Pick / Vent Hole
No
Vitrified Clay Pipe
vented Normal
Fair
Active Drop Connections Air Quality:
Communication Type
Normal
26'' 54''
Manhole Cover Manhole Frame
Pipe Condition:
Manhole Material:
Manhole Diameter (Approx.):
Manhole Depth (Approx. FT): Manhole Configuration
Concrete Poor
165"
Manhole Condition:
Upstream 0-5 FT Manhole
Sensors / Devices:
Installation Confirmation:
Manhole Opening Diameter (in)
Silt Type
Hydraulic Comments:
0''
Single
0.25"
Manhole / Pipe Information:
Pressure Sensor Range (psi)
Confirmation Time:
Hard Packed
Peak Combo (CS4)
Pipe Size (HxW)
0 Downlooker Physical Offset (in) Measurement Confidence (in) NA
Peak Velocity (fps)
Silt (in)
3:50am 17.75" X 17.88"
Smooth flow with medium depth and slow velocity
0 - 5 psi
Depth of Flow (Wet DOF) (in) Range (Air DOF) (in)
4.63"
Velocity Sensor Offset (in)
0.77 Installation Information
Circular
Monitor Series
Monitor Location:
Doppler Standard Ring and Crank
Manhole #
Installation Date:
Pipe Size (H x W)
Topside / Area Photo
Tuesday, February 25, 2025
Access
Temporary
17.75" X 17.88"
Traffic
UNK Residential/Commercial
Map
Installation Type:
Monitoring Location (Sensors):
EC_FM08_UNK
TRITON+ VZ
System Characteristics
Location Type
Pipe Shape DRIVE
ElCentro.Dudek.TFM.CA24
Drive None
Site Access Details:
Site Address /Location:
22843.22.325
1498 Manuel Ortiz Ave, El Centro, CA 92243
Flow Monitoring
Site Report
43
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Hydrograph Report
EC_FM08_UNK
44
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Scattergraph Report
EC_FM08_UNK
45
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Daily Tabular Report
03/06/2025 00:00 - 03/19/2025 23:59
EC_FM08_UNKPipe: Elliptical (17.88 in H x 17.75 in W), Silt0.00 in DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total MG)
Date Time Min Time Max Avg Time Min Time Max Avg Time Min Time Max Avg Total 03/06/2025 04:45 3.67 09:10 7.12 5.31 03:50 0.23 09:10 1.05 0.71 03:50 0.040 09:10 0.438 0.204 0.204 03/07/2025 03:40 4.10 17:20 6.01 5.32 04:30 0.37 17:20 0.86 0.69 03:40 0.072 17:20 0.282 0.197 0.197 03/08/2025 04:25 3.99 12:40 6.10 5.26 04:25 0.29 12:50 0.86 0.67 04:25 0.054 12:50 0.289 0.188 0.188 03/09/2025 04:25 4.14 20:50 6.34 5.31 04:30 0.36 20:50 0.90 0.68 04:25 0.071 20:50 0.319 0.195 0.195 03/10/2025 03:50 4.07 20:50 6.29 5.36 03:50 0.38 22:25 0.90 0.68 03:50 0.072 20:50 0.310 0.197 0.197 03/11/2025 04:40 4.05 22:15 6.54 5.24 05:30 0.38 22:15 0.90 0.66 03:00 0.077 22:15 0.333 0.184 0.184 03/12/2025 04:20 3.90 22:00 6.21 5.22 04:20 0.29 21:10 0.86 0.65 04:20 0.053 21:10 0.293 0.180 0.180 03/13/2025 05:00 4.01 22:25 6.19 5.26 03:50 0.32 23:05 0.83 0.64 03:50 0.063 22:25 0.280 0.179 0.179 03/14/2025 05:00 3.86 22:00 6.08 5.25 04:10 0.30 22:00 0.90 0.66 04:10 0.055 22:00 0.302 0.183 0.183 03/15/2025 04:00 4.05 12:25 6.26 5.29 04:25 0.36 11:20 0.87 0.67 04:25 0.070 11:55 0.293 0.189 0.189 03/16/2025 04:50 3.91 22:10 6.83 5.29 04:30 0.31 20:45 0.97 0.64 04:30 0.059 20:45 0.378 0.184 0.184 03/17/2025 03:30 3.70 11:30 7.19 5.34 03:25 0.20 11:25 0.93 0.65 03:25 0.034 11:25 0.364 0.190 0.190 03/18/2025 04:45 3.89 22:15 6.91 5.31 03:00 0.32 23:20 0.89 0.67 04:45 0.059 23:20 0.336 0.192 0.192 03/19/2025 03:25 3.76 10:45 8.19 5.39 03:15 0.24 06:15 0.91 0.64 03:15 0.044 10:45 0.435 0.190 0.190 03/06/2025 00:00 - 03/19/2025 23:59
DFINAL
(in)
VFINAL
(ft/s)
QFINAL
(MGD -
Total MG)
Total 2.652
Average 5.30 0.66 0.189
46
EC_FM09_22-17-104
Site Commentary
SITE INFORMATION
OBSERVATIONS
Average flow depth, velocity, and quantity data observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025, along with observed minimum and maximum data, are provided in the following table.
During the monitoring of this site, a large amount of silt and debris was observed. Equipment was removed on March 4th, 2025 for line cleaning and reinstalled on March 5th, 2025.
Observed Flow Conditions
Item DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total
MG)
Average 4.87 0.73 0.236
Minimum 3.61 0.45 0.099
Maximum 6.63 1.08 0.391
Min Time 03/19/2025 6:10:00 AM 03/12/2025 7:20:00 AM 03/19/2025 6:10:00 AM Max Time 03/13/2025 2:15:00 PM 03/15/2025 10:20:00 PM 03/09/2025 4:50:00 PM Based upon the quality and consistency of the observed flow depth and velocity data, the Continuity equation was used to calculate flow rate and quantities during the monitoring period.
Values in the Observed Flow Conditions are based off the five minute average.
Values in the graphical reports are based off the fifteen minute average.
Values in the tabular report are based off the five minute average.
DATA UPTIME
Data uptime observed during Thursday, 06 March 2025 to Wednesday, 19 March 2025 is provided in the following table:
Percent Uptime
DFINAL (in) 100
VFINAL (ft/s) 100
QFINAL (MGD - Total MG) 100
Pipe Elliptical (26 in H x 27 in W)
Silt 0.00 (in)
47
Latitude: 32.7945838
Longitude: 115.5269849
Site Sketch Profile View or Photo
Sensor Shot
EC_FM09_22-17-104
TRITON+ VZ
System Characteristics
Location Type
Pipe Shape DRIVE
ElCentro.Dudek.TFM.CA24
Drive Light
Site Access Details:
Site Address /Location:
22843.22.325
202 N Earls St
Flow Monitoring
Site Report
Installation Information
Elliptical
Monitor Series
Monitor Location:
Doppler Standard Ring and Crank
Manhole #
Installation Date:
Pipe Size (H x W)
Topside / Area Photo
Tuesday, February 25, 2025
Access
Temporary
26.00'' x 27.00''
Traffic
22-17-104 Residential/Commercial
Map
Installation Type:
Monitoring Location (Sensors):
Peak Combo (CS4)
Pipe Size (HxW)
1.5"
Downlooker Physical Offset (in) Measurement Confidence (in)
2.88"
Peak Velocity (fps)
Silt (in)
6:42am 26.00'' x 27.00''
Smooth flow with medium depth and slow velocity. Some silt/debris 0 - 5 psi
Depth of Flow (Wet DOF) (in) Range (Air DOF) (in)
6.00"
Velocity Sensor Offset (in)
0.23 Upstream 0-5 FT Manhole
Sensors / Devices:
Installation Confirmation:
Manhole Opening Diameter (in)
Silt Type
Hydraulic Comments:
0''
Single
0.25"
Manhole / Pipe Information:
Pressure Sensor Range (psi)
Confirmation Time:
Sandy / Gravel
N/A
26'' 54''
Manhole Cover Manhole Frame
Pipe Condition:
Manhole Material:
Manhole Diameter (Approx.):
Manhole Depth (Approx. FT): Manhole Configuration
Concrete Fair
174"
Manhole Condition:
22843.22.325
Additional Site Info. / Comments:
ADS Project Name:
ADS Project Number:
ElCentro.Dudek.TFM.CA24
Wireless
Pipe Material
Antenna Location
Communication Information:
Manhole Pick / Vent Hole
No
Concrete
Vented Normal
Fair
Active Drop Connections
After installation a flow change was noted and during field service lots of new debris was observed. City performed a line cleaning and flow meter was reinstalled. There is a data gap due to the debris but 2-weeks of data from March 6th- 19th was collected.
Air Quality:
Communication Type
Normal
48
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Hydrograph Report
EC_FM09_22-17-104
49
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Scattergraph Report
EC_FM09_22-17-104
50
48020 Mercury St #C
San Diego, CA 92111
800-633-7246
www.adsenv.com
Daily Tabular Report
03/06/2025 00:00 - 03/19/2025 23:59
EC_FM09_22-17-104Pipe: Elliptical (26 in H x 27 in W), Silt0.00 in DFINAL (in) VFINAL (ft/s) QFINAL (MGD - Total MG)
Date Time Min Time Max Avg Time Min Time Max Avg Time Min Time Max Avg Total 03/06/2025 05:50 3.76 22:05 5.76 4.77 04:50 0.61 13:30 0.89 0.72 04:50 0.137 14:40 0.297 0.225 0.225 03/07/2025 06:05 4.01 16:40 6.18 5.12 06:15 0.52 16:25 0.75 0.67 06:15 0.127 16:30 0.335 0.236 0.236 03/08/2025 07:00 4.05 20:05 6.50 5.26 05:50 0.53 23:20 0.86 0.66 05:50 0.133 20:20 0.336 0.241 0.241 03/09/2025 08:25 3.87 19:05 6.22 5.01 05:20 0.58 16:20 0.87 0.74 05:20 0.138 16:50 0.391 0.251 0.251 03/10/2025 05:55 4.02 18:15 6.20 5.20 06:30 0.53 11:15 0.74 0.65 06:30 0.129 20:15 0.310 0.229 0.229 03/11/2025 06:10 4.19 20:35 6.30 5.36 06:45 0.50 23:10 0.62 0.57 06:45 0.130 20:15 0.281 0.212 0.212 03/12/2025 07:10 4.16 16:55 6.59 5.50 07:20 0.45 16:40 0.64 0.56 07:20 0.115 17:05 0.316 0.218 0.218 03/13/2025 06:50 4.25 14:15 6.63 5.05 04:35 0.46 14:55 0.93 0.68 05:35 0.130 14:55 0.332 0.232 0.232 03/14/2025 05:40 3.82 19:15 5.38 4.67 06:10 0.67 21:30 1.00 0.86 06:10 0.151 19:15 0.341 0.262 0.262 03/15/2025 07:00 3.72 16:50 5.27 4.62 06:20 0.69 22:20 1.08 0.91 06:20 0.152 16:35 0.383 0.275 0.275 03/16/2025 08:30 3.72 17:30 5.37 4.50 07:00 0.72 18:25 1.03 0.92 07:00 0.156 16:50 0.373 0.269 0.269 03/17/2025 07:05 3.64 20:10 5.07 4.42 07:20 0.70 12:15 1.00 0.89 07:20 0.149 20:10 0.332 0.252 0.252 03/18/2025 06:10 3.64 16:40 4.94 4.32 06:10 0.58 00:30 0.88 0.77 06:10 0.123 16:50 0.271 0.210 0.210 03/19/2025 06:10 3.61 16:55 4.98 4.40 06:30 0.48 20:15 0.78 0.67 06:10 0.099 16:55 0.254 0.190 0.190 03/06/2025 00:00 - 03/19/2025 23:59
DFINAL
(in)
VFINAL
(ft/s)
QFINAL
(MGD -
Total MG)
Total 3.302
Average 4.87 0.73 0.236
51
RG_02
Site Commentary
SITE INFORMATION
OBSERVATIONS
The Total rainfall recorded during the study period was 0.05 inches.
RainGauge 8" Tipping Bucket
52
Latitude: 32.7893899
Longitude: 115.550877
RG_02
Rain Alert III
System Characteristics
Location Type
Pipe Shape DRIVE
ElCentro.Dudek.TFM.CA24
Drive None
Site Access Details:
Site Address /Location:
23124.11.325
307 W Brighton Ave, El Centro, CA 92243
Flow Monitoring
Site Report
Installation Information
Monitor Series
Monitor Location:
Rain Gauge
Manhole #
Installation Date:
Pipe Size (H x W)
Topside / Area Photo
Wednesday, February 26, 2025
Access
Temporary
0 Traffic
N /A Other
Map
Installation Type:
Monitoring Location (Sensors):
Rain Gauge Tipping Bucket
Pipe Size (HxW)
0 Downlooker Physical Offset (in) Measurement Confidence (in) N/A
Peak Velocity (fps)
Silt (in)
8:35:00 AM 0
0 - 5 psi
Depth of Flow (Wet DOF) (in) Range (Air DOF) (in)
0.00 Velocity Sensor Offset (in)
N/A
Rooftop Building
Sensors / Devices:
Installation Confirmation:
Manhole Opening Diameter (in)
Silt Type
Hydraulic Comments:
0''
Single
0.25"
Manhole / Pipe Information:
Pressure Sensor Range (psi)
Confirmation Time:
Sandy / Gravel
0 0
Manhole Cover Manhole Frame
Pipe Condition:
Manhole Material:
Manhole Diameter (Approx.):
Manhole Depth (Approx. FT): Manhole Configuration
Unknown Good
0 Manhole Condition:
23124.11.325
Additional Site Info. / Comments:
ADS Project Name:
ADS Project Number:
ElCentro.Dudek.TFM.CA24
Wireless
Pipe Material
Antenna Location
Communication Information:
Cabinet
No
Unknown
vented Normal
Fair
Active Drop Connections Air Quality:
Communication Type
53
Hydrograph Report
RG_02
54
Daily Tabular Report
03/06/2025 00:00 - 03/19/2025 23:59
RG_02 Rain Gauge:
Rain (in)
Date Total
03/06/2025-
03/07/2025-
03/08/2025-
03/09/2025-
03/10/2025-
03/11/2025 0.01
03/12/2025-
03/13/2025 0.04
03/14/2025-
03/15/2025-
03/16/2025-
03/17/2025-
03/18/2025-
03/19/2025-
03/06/2025 00:00 - 03/19/2025 23:59
Rain (in)
Total 0.05
Average
55
Appendix E
Dry Weather Model Calibration Results
APPENDIX E – DRY WEATHER CALIBRATION CURVES
E-1
APPENDIX E – DRY WEATHER CALIBRATION CURVES
E-2
APPENDIX E – DRY WEATHER CALIBRATION CURVES
E-3
APPENDIX E – DRY WEATHER CALIBRATION CURVES
E-4
APPENDIX E – DRY WEATHER CALIBRATION CURVES
E-5
APPENDIX E – DRY WEATHER CALIBRATION CURVES
E-6
APPENDIX E – DRY WEATHER CALIBRATION CURVES
E-7
APPENDIX E – DRY WEATHER CALIBRATION CURVES
E-8
APPENDIX E – DRY WEATHER CALIBRATION CURVES
E-9
Appendix F
Pipeline Condition Assessment Data &
Recommendations Log
APPENDIX F: CONDITION ASSESSMENT DATA
Pipeline Data Inspection Data
Street Name / Location
Description Pipeline ID Pipe Length (ft) Diameter (inch) Material CCTV Report file name Date Televised Direction Televised Length Televised (ft) Reviewer General Condition Notes Lateral Notes Recommendation Notes Final Recommendation Project ID Imperial Ave GM-121025 167.3 12 VCP
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
10/23/2024 DS 167.3 KJ
DAGS
JOS
CS
CL (many)
IDJ
CC
JSM
LINE LINE PCON-2
Imperial Ave GM-18-121050 90.6 8 CLC
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
11/7/2024 DS 90.6 KJ
IDJ
JOS
DAGS 5% NO REPAIR -
Imperial Ave GM-18-121052 321.0 12 CLC
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
11/8/2014 DS 321.0 KJ
DAGS
JOS
IDJ
TF (3) NO REPAIR -
Imperial Ave/South of Ross
Ave GM-19-121011 173.5 8 CLC
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
11/9/2024 DS 173.5 KJ
DAGS
JOS
CL
TF EXT PT RP Crack is near tap factory EX PT RP PCON-1
Imperial Ave/South of Ross
Ave GM-19-121031 308 8 CLC
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
11/9/2024 DS 308 KJ
JOS
DAGS NO REPAIR -
Imperial Ave /Pepper GM-19-121049 332 12 CLC
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
11/8/2014 DS 332 KJ
JOS
DAGS NO REPAIR -
Imperial Ave/Wesley GM-19-121049 304.8 8 VCP
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
10/1/2024 DS 304.8 KJ
JOS
DAGS
CL TF EXT PT RP EX PT RP PCON-1
Imperial Ave GM-19-121050 374.4 12 CLC
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
11/8/2014 DS 374.4 KJ
JOS
DAGS TF NO REPAIR -
Imperial Ave/South of Ross
Ave GM-19-121051 434 12 CLC
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
11/8/2014 DS 434 KJ
JOS
DAGS NO REPAIR -
Condition Assessment
F-1
APPENDIX F: CONDITION ASSESSMENT DATA
Pipeline Data Inspection Data
Street Name / Location
Description Pipeline ID Pipe Length (ft) Diameter (inch) Material CCTV Report file name Date Televised Direction Televised Length Televised (ft) Reviewer General Condition Notes Lateral Notes Recommendation Notes Final Recommendation Project ID Condition Assessment
Imperial Ave/Ross Ave GM-19-121051 433.8 12 VCP
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
9/30/2024 DS 433.8 KJ
JOS
DAGS
IDJ NO REPAIR -
Imperial Ave/South of Ross
Ave GM-19-121066 473.6 12 CLC
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
11/8/2014 DS 473.6 KJ
DAGS
JOS
IDJ
CL (14 in)
TF (2)
EXT PT RP
Trim (1) lateral near
crack
HEAVY CLEANING to
remove deposits
EX PT RP, HEAVY
CLEANING PCON-1
Imperial Ave/South of Ross
Ave GM-20-121017 305.1 8 CLC
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
11/9/2024 DS 305.1 KJ
JOS
DAGS TF NO REPAIR -
Imperial Ave/Wesley GM-20-121017 60.9 12 VCP
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
10/1/2024 DS 60.9 KJ
JOS
DAGS NO REPAIR -
Imperial Ave GM-20-121025 152.1 12 VCP
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
10/23/2024 DS 152.1 KJ
JOS
DAGS
CM
JON
CC
IDJ
LINE LINE PCON-2
Imperial Ave/South of Ross
Ave GM-20-121033 140.2 8 CLC
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
11/9/2024 DS 140.2 KJ
JOS
DAGS TF NO REPAIR -
Imperial Ave GM-20-121039 180.0 8 VCP
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
10/2/2024 DS 180.0 KJ
JOS
DAGS NO REPAIR -
Imperial Ave GM-20-121042 235.5 12 VCP
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
10/2/2024 DS 235.5 KJ
JOS
DAGS
IDJ
FL
CL
LINE LINE PCON-2
Imperial Ave GM-20-121043 277.7 12 VCP
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
10/2/2024 DS 277.7 KJ JOS DAGS NO REPAIR -
F-2
APPENDIX F: CONDITION ASSESSMENT DATA
Pipeline Data Inspection Data
Street Name / Location
Description Pipeline ID Pipe Length (ft) Diameter (inch) Material CCTV Report file name Date Televised Direction Televised Length Televised (ft) Reviewer General Condition Notes Lateral Notes Recommendation Notes Final Recommendation Project ID Condition Assessment
Imperial Ave GM-20-121049 32.4 12 VCP
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
10/2/2024 DS 32.4 KJ
JOS
CM
DAGS
JON
FC
LINE LINE PCON-2
Imperial Ave GM-20-121053 35.7 12 VCP
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
10/2/2024 DS 35.7 KJ
JOM
DAGS
JOS
LINE
Line joint offset medium
between 1.7 and 6.1 ft
LINE PCON-2
Imperial Ave GM-20-121055 226.0 12 VCP
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
10/22/2024 DS 226.0 KJ
JOS
CL (many)
DAGS
IDJ
CM
LINE LINE PCON-2
Imperial Ave GM-20-121066 87.5 12 VCP
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
10/2/2024 DS 87.5 KJ
JOS
CH3
CC
CL
FC
DAGS
IDJ
LINE LINE PCON-2
Imperial Ave/Ross Ave GM-20-121069 448.1 12 VCP
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
10/1/2024 DS 448.1 KJ
JOS
DAGS
IDJ
ID
NO REPAIR -
Imperial Ave GM-20-121070 150.3 12 VCP
CCTV_FINAL Report_12-22-2024
Imperial Ave - Ocotillor Dr to Brighton
Ave.pdf
10/23/2024 DS 150.3 KJ
SSS
CL (many)
JOS LINE LINE PCON-2
Main St GM-21-131023 181.1 8 VCP Section_1_5_21_2025 7_24_05 AM.pdf 5/21/2025 DS 181.1 KJ CL
CC
CM TF(2), TFA(3) LINE LINE PCON-2
Main St GM-21-131045 188.6 8 VCP Section_1_5_21_2025 5_51_40 AM.pdf 5/21/2025 US 188.6 KJ CC
TBA
CL
CM
TF(6), TBA, TFA(5) LINE LINE PCON-2
Main St GM-21-131046 168.3 8 VCP Section_1_5_21_2025 6_28_45 AM.pdf 5/21/2025 DS 168.3 KJ CC
CL TF(3), TFA(5) LINE LINE PCON-2
F-3
APPENDIX F: CONDITION ASSESSMENT DATA
Pipeline Data Inspection Data
Street Name / Location
Description Pipeline ID Pipe Length (ft) Diameter (inch) Material CCTV Report file name Date Televised Direction Televised Length Televised (ft) Reviewer General Condition Notes Lateral Notes Recommendation Notes Final Recommendation Project ID Condition Assessment
Main St GM-21-141027 363.5 8 CLAY Section_1_5_20_2025 9_39_20 AM.pdf 5/20/2025 DS 363.5 KJ HSV
CC
CL
CM
TB
TBA
TF(16), TFA (11),
TBA, TB,
LINE, PRIORITIZE
BASED ON LARGE
SECTIONS OF
BROKEN PIPE
LINE PCON-2
State St GM-21-141024 145.7 8 VCP Report 3-17-2025.pdf 3/17/2025 DS 145.7 KJ BSV
SMW
B
CC
CL
CM
TSB
TBA
TF(3), TSB, TBA,
TFA
LINE, PRIORITIZE
BASED ON LARGE
SECTIONS OF
BROKEN PIPE
LINE PCON-2
Villa Ave GM-23-131016 370.0 27 VCP V51-V52, 20190212_VillaAveSwrMHs.pdf 4/10/2015 DS 370.0 KJ Already Lined NO REPAIR - Villa Ave GM-23-131009 100.0 27 VCP V51-V52, 20190212_VillaAveSwrMHs.pdf 4/10/2015 DS 100.0 KJ Already Lined NO REPAIR - Villa Ave GM-23-131008 328.0 27 PVC V52-V53, 20190212_VillaAveSwrMHs.pdf 4/14/2015 DS 270.0 KJ Multiple sags in pipe,
varying water level,
material changes to PVC to
Con to VCP
Re-CCTV prior to final
recommendaion; if not
already lined, LINE.
PRIORITIZE DUE TO
SEVERE SAGS
Re-CCTV and LINE PCON-2
Villa Ave GM-23-131017 270.0 27 VCP V53-V54, 20190212_VillaAveSwrMHs.pdf 4/15/2015 DS 250.0 KJ Re-CCTV prior to final
recommendaion; if not
already lined, LINE.
PRIORITIZE DUE TO
SEVERE SAGS
Re-CCTV and LINE PCON-2
Villa Ave GM-23-131029 42.0 27 VCP V54-V55, 20190212_VillaAveSwrMHs.pdf 4/15/2015 DS 84.0 KJ Materila changes to PVC, high fluctuations in flow (5% to 40%) due to sag Re-CCTV prior to final
recommendaion; if not
already lined, LINE.
PRIORITIZE DUE TO
SEVERE SAGS
Re-CCTV and LINE PCON-2
Villa Ave GM-23-131020 200.0 27 PVC V55-V56, 20190212_VillaAveSwrMHs.pdf 4/15/2015 DS 23.0 KJ High water level Re-CCTV prior to final
recommendaion; if not
already lined, LINE.
PRIORITIZE DUE TO
SEVERE SAGS
Re-CCTV and LINE PCON-2
F-4
APPENDIX F: CONDITION ASSESSMENT DATA
Pipeline Data Inspection Data
Street Name / Location
Description Pipeline ID Pipe Length (ft) Diameter (inch) Material CCTV Report file name Date Televised Direction Televised Length Televised (ft) Reviewer General Condition Notes Lateral Notes Recommendation Notes Final Recommendation Project ID Condition Assessment
Villa Ave GM-23-131020 200.0 27 VCP V57- V58, 20190212_VillaAveSwrMHs.pdf 4/15/2015 US 163.0 KJ Severe sag at U/S MH,
Survey Abandoned due to
severe sag at 163', 80%
water level where sag
occurs, infiltration drip @
16'10'' and 33'3''
Re-CCTV prior to final
recommendaion; if not
already lined, LINE.
PRIORITIZE DUE TO
SEVERE SAGS
Re-CCTV and LINE PCON-2
Adams Ave & 4th St GM-22-141024 423.0 22 VCP MH 1_MH 2 _2025-01-14_0.pdf 1/14/2025 DS 432.0 KJ Tap Break, SEVERE Root
Intrusion Throughout,
Cracks and significantly
reduced capacity due to
roots
Root Removal pre-lining,
and then LINE Root Removal and LINE PCON-2
Adams Ave & 4th St GM-22-141023 112.0 27 Brick MH 2_MH 3 _2025-01-14_1.pdf 1/14/2025 DS 120.0 KJ Root Intrusion, Cracks,
Water mist throughout
makes visibility low
Re-CCTV due to low
video quality and to
ensure no inflitration is
occuring, LINE due to old
age of Brick Sewer
Re-CCTV and LINE PCON-2
Adams Ave & 4th St GM-22-141019 61.0 27 Brick MH 3_MH 4 _2025-01-14_2.pdf 1/14/2025 DS 55.0 KJ Water mist throughout
makes visibility low,
droplets likely due to
condensation or to
infiltration
Re-CCTV due to low
video quality and to
ensure no inflitration is
occuring, LINE due to old
age of Brick Sewer
Re-CCTV and LINE PCON-2
Adams Ave & 4th St GM-22-141022 341.0 27 Brick MH 4_MH 5 _2025-01-15_0.pdf 1/15/2025 DS 335.0 KJ Possible Infiltration
throughout (could also be
condensation),
Re-CCTV due to low
video quality and to
ensure no inflitration is
occuring, LINE due to old
age of Brick Sewer
Re-CCTV and LINE PCON-2
F-5
Appendix G
Staffing Plan Technical Memorandum
TECHNICAL MEMORANDUM – STAFFING STUDY
To: Abraham Campos and Liz Zarate, City of El Centro
From: Dudek
Subject: Staffing Study for City of El Centro
Date: October 23, 2025
This Technical Memorandum (TM) provides high level investigations and analysis to date, along with recommended next steps to support the City of El Centro (City) in evaluating staffing needs for the water, sewer, and engineering divisions of the City’s Public Works Department.
1 Introduction
As part of the City of El Centro’s Water and Sewer Master Plans and Rate Study, this staffing analysis has been developed to estimate the additional personnel required to support the City’s objectives for effective management of its water and wastewater systems. The scope of work considered in this study includes routine maintenance activities such as pipeline cleaning, lift station and booster station inspections, closed-circuit television (CCTV) inspections, infrastructure rehabilitation and replacement, and operations and maintenance of the water amd wastewater treatment plants.
By expanding its workforce, the City aims to enhance system reliability and operational efficiency. This study also establishes a staffing framework for the divisions within the Public Works Department responsible for managing both water and sewer systems. Key staff groups include personnel at the Water Treatment Plant (WTP), Wastewater Treatment Plant (WWTP), Underground Utilities staff within the Streets and Utilities Division, and Engineering staff.
As a full-service municipality, the City of El Centro provides potable water and sanitary sewer services to approximately 43,000 residents within an 11-square-mile service area. The City oversees the treatment and distribution of drinking water at the El Centro Water Treatment Plant and the collection and treatment of wastewater at the El Centro Wastewater Treatment Plant. A summary of the City’s major infrastructure assets is presented in Table 1.
Table 1. City of El Centro’s Sewer System and Water System Assets Facilities Quantity
Sewer Collection System
Gravity Mainlines 123 miles
Pressure Force Mains 6.4 miles
Lift Stations 15
WWTP
Rated Capacity / Current Average Daily Flow 8 MGD / 3.5 MGD Potable Water System
Water Pipelines (transmission mains and distribution mains) 157 miles Booster Stations 2
Storage Reservoirs/ Tanks 8
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Facilities Quantity
WTP
Rated Capacity / Current Average Daily Production 21 MGD / 7.2 MGD The following sections outline the methodology used to estimate staffing requirements to maintain the City’s WTP, WWTP, sewer collection system, and potable water system.
Sources of data used for this analysis include:
• publicpay.ca.gov, a website that lists government compensation in the state of California • Publicly listed agency NPDES permits
• Publicly listed agency organizational charts
2 Limitations of the Evaluation
Several limitations should be considered when interpreting the results of this staffing evaluation:
• A comprehensive staffing analysis is typically conducted by a financial consultant and includes detailed financial modeling and long-term budgeting, which were beyond the scope of this study. • Complete staffing plans or evaluations were obtained from only one agency. Most of the data used in this analysis was gathered through online research and publicly available documents. • The full scope of staffing roles and responsibilities across agencies was not assessed. For example, while staff in the City of El Centro’s Wastewater Treatment Plant (WWTP) Division also maintain lift stations, other agencies may assign lift station operations to dedicated collection system staff. • The extent to which neighboring agencies may be understaffed is unknown. • Information regarding the implementation of 24/7 staffing rotations at comparable facilities is not available.
• Staffing levels are influenced by each agency’s available funding, which varies based on numerous factors. • Sewer System Management Plans (SSMPs), which often include organizational charts for sewer system staffing, were more readily available online than those for water system staffing. As a result, more detailed information was obtained for sewer-related staffing.
Given these limitations, the analysis presented herein is based on the best available data and is intended to provide a general framework for evaluating staffing needs.
3 Current Staffing Structure
The current organizational structure of the City of El Centro’s Public Works Department is illustrated in Figure 1. The department is divided into six functional groups: Administration, Building and Facility Maintenance, Wastewater
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Treatment Plant (WWTP) staff (including lift station operations), Water Treatment Plant (WTP) staff, Streets and Utilities staff, and Engineering.
Table 2 outlines the number of full-time equivalents (FTEs) currently assigned to divisions responsible for maintaining the sewer collection and potable water distribution systems. Based on discussions with City staff, eight operators within the Streets and Utilities group are dedicated to the water system, while three operators are assigned to sewer system operations. Additionally, a single Instrumentation Electrical Technician supports both the WWTP and WTP teams.
Table 2. City of El Centro Public Works Department’s Number of Full Time Employees
Department
Number of
FTEs Currently
WWTP/Lift Station Staff 13
WTP Staff
WTP Operations Staff
Meter Staff (included in WTP Group)
Backflow Prevention
13.5 8
5 0.5
Instrumentation Electrical Technician (shared
between Water and Sewer)
1 Underground Utilities Staff – Water 8
Underground Utilities Staff – Sewer 3
Engineering 5
Administration (excluding Fleet Staff) 6
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Figure 1. City of El Centro Public Works Department Organizational Structure
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4 Staffing Studies
A review of El Centro’s job description data was performed. The primary services of staff that maintain the sewer collection system are outlined in Table 3. The services related to the maintenance of the potable water system are outlined in Table 4.
Table 3. City of El Centro Main Services for Maintenance of Sewer Collection System Department
Services
WWTP Staff
• Inspects, operates, and maintains sewer lift stations, stormwater lift stations, and wastewater treatment plant facilities.
• Ensures compliance with all local, state, and federal rules and regulations • Works to improve efficiency and effectiveness of operations. • Oversees and coordinates lift station operations and maintenance. • Confers with contractors, consultants, and the public on engineering and construction matters.
• Prepares reports on public works projects.
• Performs routine cleaning duties of City buildings and facilities. • Performs basic maintenance and repair of facilities and grounds by performing semi-skilled work involving plumbing, painting, electrical, mechanical and carpentry repairs.
• Performs water quality and other laboratory testing for regulatory compliance, industrial waste source control, and plant process control; perform related responsibilities as required.
• Performs specialized and skilled work in the design, construction, installation, calibration, and maintenance of electrical and instrumentation equipment at City’s wastewater facilities.
Underground Utilities Staff
– Sewer Operator
• Cleans, unplugs, maintains and services sewer lines
• Operates backhoe, dump truck, skip loader, forklift, and other equipment • Install, taps, repairs, and relocates sewer lines
Instrumentation Electrical
Technician
• Installs, maintains, troubleshoots, and repairs electronic components and instrumentation pertinent to the wastewater treatment process • Inspects and maintains medium voltage electrical power distribution equipment (i.e. switchgear, transformers, circuit breakers, selector switches, feeder cables, etc.)
Engineering
• Monitor and assess the condition of the sewer collection system, including pipelines, manholes, lift stations, and related infrastructure. • Coordinate routine inspections, cleaning, and emergency repairs. • Maintain GIS and asset management databases for sewer infrastructure. • Ensure compliance with local, state, and federal regulations (e.g., NPDES, SWRCB).
• Collaborate with Operations and Maintenance teams to prioritize work orders and system upgrades.
• Develop and manage the City’s CIP for sewer and related infrastructure. • Prepare engineering designs, specifications, and cost estimates. • Oversee bidding, contracting, and construction management. • Track project budgets, schedules, and performance metrics. • Coordinate with consultants, contractors, and other departments.
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Table 4. City of El Centro Main Services for Maintenance of Water Distribution System Department
Services
WTP Staff
• Inspects, operates, and maintains water pump stations and water treatment plant facilities.
• Ensures compliance with all local, state, and federal rules and regulations. • Works to improve efficiency and effectiveness of operations. • Oversees and coordinates pump station operations and maintenance. • Confers with contractors, consultants, and the public on engineering and construction matters.
• Prepares reports on public works projects.
• Performs routine cleaning duties of City buildings and facilities. • Performs basic maintenance and repair of facilities and grounds by performing semi-skilled work involving plumbing, painting, electrical, mechanical and carpentry repairs.
• Performs water quality and other laboratory testing for regulatory compliance, and plant process control; perform related responsibilities as required. • Performs specialized and skilled work in the design, construction, installation, calibration, and maintenance of electrical and instrumentation equipment at City’s water facilities.
Underground Utilities Staff
– Water Operator
• Installs, taps, maintains, repairs, and relocates water lines • Monitors water pressure to ensure proper water flow to customers • Operates and maintains pump stations
Instrumentation Electrical
Technician
• Installs, maintains, troubleshoots, and repairs electronic components and instrumentation pertinent to the water treatment process • Inspects and maintains medium voltage electrical power distribution equipment (i.e. switchgear, transformers, circuit breakers, selector switches, feeder cables, etc.)
Engineering
• Monitor and evaluate the performance of the water distribution system, including pipelines, valves, hydrants, reservoirs, and pump stations. • Coordinate routine inspections, repairs, and replacements to ensure system integrity and water quality.
• Maintain and update GIS and asset management systems for water infrastructure.
• Ensure compliance with state and federal drinking water regulations (e.g., SWRCB, EPA).
• Collaborate with Operations staff to prioritize maintenance activities and emergency response.
• Develop and manage the City’s CIP for water infrastructure projects. • Prepare engineering designs, technical specifications, and cost estimates. • Oversee project bidding, contracting, and construction management. • Monitor project budgets, schedules, and performance metrics. • Coordinate with consultants, contractors, and other departments to ensure successful project delivery.
4.1 Methodology
To support the development of this staffing study, the following resources were reviewed:
• Organizational charts from various water and sewer service districts
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• Staffing plans from peer agencies
• The City of El Centro’s Sewer System Management Plan
• The City’s ongoing Water and Sewer Master Plan
• Notes from interviews with City staff
The methodology for estimating staffing needs began with a review of organizational structures and staffing plans from multiple agencies to identify common workforce models. Staffing ratios relative to service area size and service volume were used as benchmarks to inform the recommended structure for the City of El Centro.
Key operational metrics from the City’s Sewer System Management Plan and Water and Sewer Master Plans— including treatment capacity, production volumes, average flow rates, and total pipeline mileage—were incorporated into the analysis. These metrics served as scaling factors and were applied to peer agency staffing ratios to estimate the City’s FTE staffing requirements.
4.2 Sewer System Staffing Analysis
4.2.1 WWTP Staff
For the Wastewater Treatment Plant staffing analysis, similar agencies and municipalities were compared based on the capacity (MGD) of their WWTPs and their average daily flows. These comparisons are presented in Table 5.
Figures 2 and 3 compare FTEs for various agencies against WWTP average daily flows and wages, respectively.
Note that while the City of El Centro includes lift station maintenance in the WWTP staff, most agencies utilize collection system staff for lift station maintenance, resulting in El Centro’s WWTP staffing being proportionately higher.
Table 5. Number of Wastewater Operators in Various Districts Agency
Lift Station
Count
Average
Daily Dry
Weather
Flow (MGD)
Number of
FTEs in
WWTP
FTEs per
WWTP
Flow
(persons/
MGD) Wages ($)1
Population
Served
Novato Sanitary
District
2 7 10 1.4 1,166,664 60,000
City of Imperial 0 2.4 6 2.5 1,551,074 22,866
City of Coachella 1 4.5 8 1.7 788,269 345,056
City of Brawley 3 5.9 8 1.4 448,153 28,952
City of Calexico 0 4.3 7 1.6 551,502 40,073
City of Petaluma 9 6.7 28 4.2 3,490,673 59,094
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Agency
Lift Station
Count
Average
Daily Dry
Weather
Flow (MGD)
Number of
FTEs in
WWTP
FTEs per
WWTP
Flow
(persons/
MGD) Wages ($)1
Population
Served
City of El Centro 15 3.5 13 3.7 937,256 44,000
Note:
1 Wage values per publicpay.ca.gov.
Figure 2. Full Time Equivalent Staff Members Relative to Average Daily Dry Weather Flow
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Figure 3. Staff Wages Relative to Average Daily Dry Weather Flow
El Centro’s projected 2045 average dry weather flow of 4.7 MGD and peak wet weather flow of 9 MGD require a workforce capable of managing routine operations as well as high-flow events. Comparative analysis with other municipalities indicates that El Centro’s staffing levels are within the typical range of staffing observed in similar municipalities, but given El Centro’s larger quantity of lift stations, an additional operator with a mechanical technologist certificate as well as a dedicated instrumentation electrician technician is recommended, as shown in Table 6.
Table 6. Current and Recommended WWTP FTEs in El Centro Current Staffing and Productivity
Lift Station Count 8
Current Average Dry Weather Flow (MGD) 3.5
Current Peak Wet Weather Flow (MGD) 8.0
Current WWTP Operations and
Maintenance FTEs
13 Current Instrumentation Electrical
Technicians
0.5 (shared with
WTP)
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Recommended Future Staffing and Productivity
Projected Dry Weather Flow (MGD) 4.7
Projected Peak Wet Weather Flow (MGD) 9.0
Recommended WWTP Operations &
Maintenance FTEs
14 Recommended WWTP Instrumentation
Electrical Technicians
1 (dedicated to
WWTP)
4.2.2 Sewer Collection System Staff
To conduct a staffing analysis specifically for the maintenance of the sewer system, CCTV inspection and cleaning requirements will be reviewed to determine the staffing needs for each task. This analysis also considers the number of days staff are available throughout the year, as detailed in Table 7.
Table 7. Annual Crew Availability
Workday Availability Notes
Days Available/Year/Crew 260 5 days a week for 52 weeks Allowance for Benefits (15%) 39 12 holidays, 10 sick, 3 weeks (17 days) paid vacation
Allowance for Field Resolution (15%) 39 Equipment down time Allowance for Special Events (5%) 13 Trainings, meetings Net Annual Available Days/Crew 169
According to the City’s SSMP, the goal is to CCTV inspect 20% of the sewer system each year in order to meet their goal of inspecting the entire system, 157 miles or 828,960 linear feet (LF), every five years. Currently, inspections are done on an as-needed basis and are conducted manually by CCTV camera crews, with an assumed production rate of 1,000 linear feet (LF) per day. This rate is a standard estimate used to calculate staffing needs based on crew availability throughout the year. Table 8 outlines the assumptions used to determine the number of additional staff required.
The City also plans to purchase a CCTV inspection truck within the next five to ten years. Once implemented, this automated method is expected to significantly increase the inspection production rate.
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Table 8. Recommended CCTV Crew Staffing
System Overview
Total System Length (LF) 828,960
Annual CCTV Inspection Goal (%) 201
Annual CCTV Inspection Goal (LF) 165,792
Required CCTV Production Rate (LF/day) 9812
Staffing & Productivity
Assumed Production Rate (LF/day) 1000
Number of days needed in a year to
accomplish annual inspection goal at
1000 LF/day
166
Net Annual Available Days/Crew 1693
Required Crews 14
Notes:
1 Assuming the entire system is cleaned every five years. 2 Annual CCTV inspection goal (LF) divided by the net annual available days per crew from Table 7.
3 Calculated in Table 7.
4 One crew is assumed to be made up of two people for this analysis.
Using the same approach as outlined for CCTV inspections, the City plans to reach their goal of cleaning the entire system every 5 years by cleaning 20% of the system each year, along with cleaning 125,000 LF of enhanced maintenance areas annually. A standard, yet conservative, cleaning production rate of 1,500 linear feet per day was used in Table 9 to estimate the staffing requirements necessary to meet this goal.
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Table 9. Recommended Cleaning Crew Staffing
System Overview
Total System Length (LF) 828,960
Annual Cleaning Goal (%) 201
Annual Cleaning Goal (LF) 165,792
Annual Cleaning Goal of Enhanced
Maintenance Areas (Hot Spots) (LF)
125,000
Required Cleaning Production Rate
(LF/day)
1,7212
Staffing & Productivity
Assumed Production Rate (LF/day) 1,500
Number of days needed in a year to clean
the entire system at 1000 LF/day
194
Net Annual Available Days/Crew 1693
Required Crews 1.5 to 24
Notes:
1 Assuming the entire system is cleaned every five years. 2 Annual cleaning goal (LF) plus annual cleaning goal of enhanced maintenance areas (LF) divided by the net annual available days per crew from Table 7. 3 Calculated in Table 7.
4 Two crews is assumed to be made up of four people for this analysis.
Table 10 presents the final sewer collection system staffing recommendations, based on Tables 8 and 9.
Table 10. Summary of Staffing Requirements
Current Crews Staffed for both CCTV inspection
and Cleaning
1.5 Required Number of Crews Total for both CCTV
inspection and Cleaning
2.5 to 3
Additional 2-Person Crews Needed
1 to 1.5
(2-3 people)
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Based on the findings in Tables 7 through 10, the staffing requirement for CCTV inspections alone is one crew consisting of two people. Sewer system cleanings require two crews of two people. Currently, 1.5 crews, or three staff members, are dedicated to sewer system maintenance. To meet the City’s goals of inspecting and cleaning 20 percent of the entire system annually and clean all their enhanced maintenance areas annually, it is recommended that staffing be increased to 2.5 to three full crews, totaling five to six people. Therefore, it is recommended two to three new staff members are hired for the sewer collection system maintenance team.
In addition to reviewing the City’s cleaning and CCTV inspection requirements, Table 11 below outlines the number of sewer operators by comparable city agencies and districts, or their recommended staffing levels. These figures were scaled and compared to the size of City of El Centro’s sewer system to assess staffing adequacy.
Table 11. Number of Sewer Collection System Staff in Various Districts Agency
Population
Served
Size of Sewer
Distribution
System (miles)
Number of FTEs
in Sewer
Distribution
Division
Miles of
Collection
System per FTE
Novato Sanitary District 60,000 235 7 33.5
Coachella Sanitary District 345,056 107 6 17.8
City of Placentia 52,000 84 7 12
City of Laguna Beach 22,723 98 8 12.3
City of El Centro 44,000 123 3 41
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As shown in Table 11., Coachella Sanitary District’s staffing plan recommends employing six full-time staff, including sewer operators and crew supervisors, to maintain a 107-mile system. In contrast, the City of El Centro operates a larger system spanning 157 miles, with only three operators currently assigned to its maintenance.
Other cities, including Placentia and Laguna Beach, manage smaller systems of 84 and 98 miles respectively, yet employ seven and eight sewer distribution operators. The table also presents the ratio of system miles per fulltime employee (FTE), highlighting that El Centro has the highest ratio at 41 miles per FTE, indicating the greatest workload per staff member among the cities compared. Based on these comparisons, it is recommended that the City of El Centro hire two to three additional full-time employees, bringing the total to five or six, to adequately support the maintenance of its sewer collection system, which supports the findings in Table 10.
4.2.3 Sewer Staffing Summary
Table 12 summarizes the total number of full-time employees needed to maintain both the sewer collection system and the WWTP, based on the analysis in Section 4.2. Based on the analysis of the sewer collection system maintenance requirements and the organizational charts for the WWTP staff, it is recommended that the City staff a total of 13 employees for the WWTP, five to six operators for sewer collection system maintenance, and one dedicated WWTP Instrumentation Electrical Technician.
Table 12. Summary of Total Recommended Full Time Employees for City of El Centro’s Sewer System Department
Current Number of
FTTs
Recommended
Additional FTEs
Recommended Total
FTEs
WWTP Staff 13 1 14
Instrumentation Electrical Technician 0.5 0.5 1
Underground Utilities Staff (Sewer
Operators)
3 2 to 3 5 to 6
4.3 Water System Staffing Analysis
4.3.1 WTP Staff
El Centro currently staffs 13 FTEs to operate its 21 MGD capacity Water Treatment Plant. This includes 8 FTEs to staff the WTP and 5 FTEs for the meter shop. The WTP is currently operating with one 8-hour shift, though the City anticipates the State of California to require staffing 16-hours per day in the next five years. Maybe WTPs in California operate with 24-hour staffing. To assess the adequacy of this staffing level, a comparative analysis was conducted using the methodology outlined in Section 4.1. This approach involved benchmarking El Centro’s staffing against similar sized municipal water treatment facilities, as shown in Table 13. The staffing of the WTP is noted in the table, if known. The comparison reveals that municipalities with smaller treatment capacities often maintain similar or even higher staffing levels. The average FTEs per MGD of WTP Capacity for the comparison agencies is
1.06, with the City of El Centro operating at a ratio of 0.4. This value indicates that increased staffing at the plant
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at the current 8-hour staffing would be supportive. To accommodate the anticipated regulatory-required shift from a single 8-hour schedule to 16-hour or 24-hour operations, a WTP staffing increase from the current 8 FTEs to up to 11 FTEs for the current 8-hour staffing and up to 22 FTEs for 16- to 24-hour staffing is justifiable. Additionally, a dedicated Instrumentation Electrical Technician is also justified. This adjustment would bring El Centro’s staffing levels in line with regional norms and ensure sufficient personnel to maintain safe, efficient, and compliant operations.
Table 13. Number of Water Treatment Plant Staff in Various Districts Agency/WTP
(Staffed hours)
WTP Rated
Capacity (MGD)
Number of FTEs
in WTP
FTEs per MGD
Capacity Wages ($)1
Population
Served
City of Imperial
(8-hrs)
7 8 1.1 535,991 22,866
City of Corona 11.5 23 2 1,928,795 160,000
City of Calexico
(24-hrs)
14 11 0.8 1,040,035 40,073
City of Brawley
(18-hrs)
15 11 0.7 721,032 28,952
Baker Water
Treatment Plant
28.1 20 0.7 3,120,175 183,000
City of El Centro
(8-hrs)
21 8 0.4 957,559 44,000
Note:
1 Wage values per publicpay.ca.gov.
The City currently staffs five FTEs in the meter shop—three permanent and two temporary employees. Based on operational needs and input from City staff, it is recommended that the meter program transition to six permanent full-time positions. This change would eliminate reliance on temporary staffing and enhance consistency, reliability, and long-term operational support.
For the backflow prevention program, the City currently relies on one part-time employee. To effectively manage hazard assessments, inspections, and regulatory compliance, it is recommended that the program be staffed with two additional FTE positions. This level of staffing would ensure consistent oversight and reduce the need for contracted support in critical public health and safety functions.
If additional support is required for backflow prevention and hazard assessment activities, the City may supplement its workforce with outside contractors. While comparative staffing data from peer agencies was not available, the City’s stated operational needs support the recommendation for these additional FTEs. Should the two recommended backflow prevention FTEs not be approved, the City plans to allocate equivalent funding toward contracted services to maintain program continuity.
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4.3.2 Water Distribution System Staff
Using the methodology outlined in Section 4.1, organizational charts from various districts were analyzed and scaled to align with the City of El Centro’s system. This approach was used to help determine the appropriate number of water distribution system operators needed. Some comparisons were made with districts significantly larger than El Centro due to limited data from similarly sized agencies. Nevertheless, ratios were applied to adjust for El Centro’s scale and ensure a more accurate analysis. Table 14 below summarizes the number of operators employed by comparable city agencies and districts as compared to the City of El Centro.
Table 14. Number of Water Distribution Staff in Various Districts Department
Population
Served
Size of Water
Distribution
System (miles)
Number of FTEs in
Water Distribution
Division
Miles of
Distribution
Pipeline per FTE
Calexico 38,000 106 6 18
City of Lomita 20,175 46 4 11.5
Brawley 28,000 75 2 38
Coachella Valley Water
District
260,000 2,075 6 346
City of Corona 160,000 800 9 89
City of El Centro 44,000 157 8 20
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The City of El Centro currently employs eight water distribution system operators, organized into two crews of four, to maintain its 157-mile water distribution system. Based on comparative data presented in Table 14, other water systems with significantly greater pipeline mileage operate with either fewer personnel or only one additional staff member. El Centro’s ratio of system miles per FTE is on the low end at 20. This suggests that the City’s current staffing level for water distribution system maintenance is generally appropriate for the size of its system.
In addition to staffing for water distribution system maintenance, valve maintenance is an important operational responsibility of waterline distribution staff. The City’s goal is to perform maintenance on all valves within the system annually. However, Table 14 does not clarify whether the staff included in the counts for comparison agencies are specifically assigned to valve maintenance or if a separate division is responsible for this task. Given the substantial effort required for both water distribution and valve maintenance, it is reasonable to assume that the staffing figures reflect only water distribution personnel, although this cannot be confirmed.
For example, Coachella Sanitary District employs 6 people for a water distribution system consisting of 2,000 miles of pipeline. This would result in a considerable about of valves requiring maintenance. It is unknown whether or not the valve maintenance staff is included in this count or is part of a separate department or division.
Last year, only 40 percent of the valves received maintenance due to limited staffing. Although the City did not provide specific data on the total number of valves or a detailed maintenance schedule, staff have indicated through their operational knowledge and experience that two additional personnel would be necessary to meet the annual maintenance goal. Therefore, it is recommended that two full-time water operators be added, dedicated specifically to valve maintenance.
4.3.3 Water Staffing Summary
Table 15 summarizes the total number of full-time employees needed to maintain the WTP, the water distribution, the meter shop and the backflow prevention program, based on the analysis in Section 4.3. Based on the findings, it is recommended that the City staff an additional 3 to 14 employees for the WTP, three permanent FTE positions for the meter shop (eliminating the two temporary positions), two backflow prevention staff, and one dedicated WWTP Instrumentation Electrical Technician.
TECHNICAL MEMORANDUM
SUBJECT: CITY OF EL CENTRO STAFFING STUDY
16707 14
OCTOBER 2025
Table 15. Summary of Total Recommended Full Time Employees for City of El Centro’s Water System Department
Current Number of
FTEs
Recommended
Additional FTEs
Recommended
Total FTEs
WTP Staff1
WTP Only (8-hr/16+hr shifts)
Meter Shop
Backflow Prevention Program
11.5 8
32 0.5
8 / 17
3 / 141
3 2
19.5 to 30.5
11 / 22
6 2.5
Underground Utilities Staff (including Water
Operators)
8 2 10
Dedicated Instrumentation Control
Electrician
0.5 0.5 1
Note:
1 WTP staffing recommendations offered for both 8-hour and 16+hr staffing options. 2 Currently the City has 5 total meter staff, including 3 permanent staff and 2 temporary staff. The City would like all meter staff to be permanent.
4.4 Engineering and Administration Staff
Following the methodology outlined in Section 4.1, organizational charts from various districts were reviewed and scaled to align with the City of El Centro’s organizational structure. The City’s Engineering Department oversees a water distribution system spanning 157 miles, including 2 booster stations and 7 storage reservoirs, as well as a sewer collection system of approximately 130 miles and 15 lift stations for approximately 44,000 residents. The City’s Engineering Department is not dedicated to utilities projects; it also oversees roads projects, development projects, grants and more. To ensure the City’s water and sewer systems are effectively maintained and that rehabilitation and replacement projects remain on schedule, it is essential that the Engineering Department is adequately staffed. Table 16 below summarizes the number of employees in the engineering department employed by comparable city agencies and districts.
The City of El Centro currently employs five staff members in its engineering division, with two being dedicated to water and sewer utilities projects and the remaining three concentrating primarily on roads projects. As shown in Table 16, this staffing level of two utilities engineers appears low when compared to other similar sized agencies.
For example, Novato Sanitary District and the Cities of Placentia and Laguna Beach manage approximately 15 to 21 miles of system per Engineering FTE while the City of El Centro is managing closer to 145. The average of the four comparative agencies included in Table 16 is 92 miles per Engineering FTE.
Many agencies also utilize outside consultants to augment engineering staff. The availability of outside consultants varies by location. Due to the more remote location of the City of El Centro, the City may seek to be generally more self-sufficient. To effectively manage both the water and sewer systems, and specifically to support water and sewer CIP projects, additional Engineering FTEs would support the City. Based on comparative analysis, it is recommended the City hire between 1 and 5 additional Engineering FTEs dedicated to water and sewer utilities work.
TECHNICAL MEMORANDUM
SUBJECT: CITY OF EL CENTRO STAFFING STUDY
16707 15
OCTOBER 2025
Table 16. Number of Employees in Engineering Division in Various Districts Department
Population
Served
Size of Sewer
Collection
System (miles)
Size of Water
Distribution
System (miles)
Number of FTEs
in Engineering
Division
Total Miles
of Systems
per FTE
City of Corona
(Utilities Only)
160,000 444 800 4 311
Novato Sanitary
District
60,000 235 N/A 16 15
City of Placentia1 52,000 84 N/A 4 21
City of Laguna
Beach1
22,723 100 N/A 5 20
City of El Centro
(Utilities Only)2
44,000 130 157 2 143.5
Notes:
1 Water service for the Cities of Placentia and Laguna Beach is provided by other agencies. These cities manage their sewer collection systems only.
2 While the City of El Centro Engineering Department consists of five FTEs, only two are dedicated to the water and sewer systems, while the remaining three handle roads projects and other work.
The City currently has six non-fleet administrative FTEs that support the Engineering Department. While data on administrative staffing was not available for comparative agencies, to support the additional FTEs in the Engineering Department, an additional one to two administrative staff would be beneficial. 5 Conclusions and Recommendations
To continue delivering high-quality services to the City of El Centro and to further enhance public health and safety, the following recommendations are provided to help the City address both current and future challenges. Based on the staffing study conducted and considering the number of existing employees in each department, Table 17 identifies the additional personnel needed beyond the City’s current staffing levels. A total of up to 31 additional FTEs would support the City in improved water and sewer systems operation.
TECHNICAL MEMORANDUM
SUBJECT: CITY OF EL CENTRO STAFFING STUDY
16707 16
OCTOBER 2025
Table 17. Summary of Recommended Additional FTEs
Department
Number of
FTEs Currently
Recommended
Additional
FTEs
Recommended
Total FTEs
WWTP/LS Staff 13 1 14
WTP Staff
WTP Operations Staff (8-hr/16+hr)1
Meter Staff
Backflow Prevention
11.5 8
32 0.5
8 to 19
3 / 14
3 2
19.5 to 30.5
11 / 22
6 2.5
Instrumentation Electrical Technicians
(Total between Water and Sewer)
1 1 2
Underground Utilities Staff – Water 8 2 10
Underground Utilities Staff – Sewer 3 2 to 3 5 to 6
Engineering 5 1 to 5 6 to 10
Administration (excluding Fleet staff) 6 1 to 2 7 to 8
Note:
1 Recommendations for WTP Operations staff provided for current (8-hour) staffing as well as the anticipated increase to 16-hour or even 24-hour staffing in the future.
2 Currently the City has 5 total meter staff, including 3 permanent staff and 2 temporary staff. The City would like all meter staff to be permanent.
Appendix H
Detailed Engineer’s Opinion of Probable Costs for
Recommended CIP Projects
APPENDIX H: RECOMMENDED CIP PROJECT COST ESTIMATE DETAILS City of El Centro
2025 Sewer Master Plan Update
Total
Project Cost ($)
PCON-1 Excavation Point Repairs Excavation point repair on the following gravity segments: Two (2) 8-inch mains; One (1) 12-inch mains
Pipeline segments have one significant structural defect or encrusted/compacted deposits that severely impact
normal sewer flow.
$ 358,000
PCON-2 CIPP Lining - No Excavation CIPP lining of thirteen (13) gravity segments, from manhole to manhole: 1,047 LF of 8-inch main; 1,087 LF
of 12-inch main. Heavy cleaning of 2,134 LF of main
prior to CIPP lining.
Pipeline segments have multiple cracks or minor
fractures.
$ 4,382,000
PCON-3 Annual CIPP Lining Program $1M Annual Ongoing Pipeline CIPP Program from Year 11 through 20.
Continued rehab of aging pipeline infrastructure to
ensure system reliability.
$ 10,000,000
$ 14,740,000
Recommended Condition Improvement Projects Cost Summary TOTAL:
Project ID Project Name Description Justification
El Centro 2025 Sewer Master Plan
APPENDIX H: RECOMMENDED CIP PROJECT COST ESTIMATE DETAILS Item No. Item Description Unit
Estimated
Quantity Unit Price Item Total
1 Point Repair of 8-inch Pipe by Excavation
up to 10 ft long EA 2 $ 30,000 $ 60,000
2 Point Repair of 12-inch Pipe by Excavation
up to 10 ft long EA 1 $ 35,000 $ 35,000
3 Reconnect Lateral after Open Trench Pipe
Replacement EA 2 $ 1,500 $ 3,000
4 Sewage Bypass and Pumping Plan (Small
Diameter, <10") EA 2 $ 10,000 $ 20,000
5 Sewage Bypass and Pumping Plan (10-18") EA 1 $ 50,000 $ 50,000 $ 168,000
General Requirements (10%) $ 17,000
Contingency (30%) $ 51,000
Construction Total: $ 236,000
Soft Costs (Small Project):
$ 71,000
$ 36,000
Engineering Services During Construction (2%) $ 5,000
$ 5,000
$ 5,000
$358,000
Administration (2%)
Project Total
PCON-1: Excavation Point Repairs (No Lining)
Subtotal
Engineering (30%)
Construction Management (15%)
Environmental (2%)
El Centro 2025 Sewer Master Plan
APPENDIX H: RECOMMENDED CIP PROJECT COST ESTIMATE DETAILS Item No. Item Description Unit
Estimated
Quantity Unit Price Item Total
1 CIPP Lining of 8-inch Pipe (includes cleaning, pre and post video inspection, traffic control, removal and
disposal of debris)
LF 1,050 $ 120 $ 126,000
2 CIPP Lining of 12-inch Pipe (includes cleaning, pre and post video inspection, traffic control, removal and
disposal of debris)
LF 1,090 $ 180 $ 196,200
3 CIPP Lining of 22-inch Pipe (includes cleaning, pre and post video inspection, traffic control, removal and
disposal of debris)
LF 435 $ 330 $ 143,550
4 CIPP Lining of 27-inch Pipe (includes cleaning, pre and post video inspection, flow diversion, traffic control, removal and disposal of debris)
LF 1,300 $ 405 $ 526,500
5 Reinstate Active Lateral Connection after CIPP Lining EA 78 $ 400 $ 31,000 6 Sewage Bypass and Pumping Plan (Small Diameter, EA 4 $ 10,000 $ 40,000 7 Sewage Bypass and Pumping Plan (10-18") EA 4 $ 50,000 $ 200,000 8 Sewage Bypass and Pumping Plan (21" and up) EA 6 $ 200,000 $ 1,200,000 9 Specialty and Heavy Cleaning LF 474 $ 25 $ 11,840
10 Trim Intruding Lateral EA 1 $ 600 $ 600
11 Service Lateral Connection Seal (Lateral Liner) EA 16 $ 400 $ 6,200 $ 2,482,000
General Requirements (10%) $ 249,000
Contingency (30%) $ 745,000
Construction Total: $ 3,476,000
Soft Costs (Medium Project):
$ 348,000
$ 348,000
Engineering Services During Construction (2%) $ 70,000
$ 70,000
$ 70,000
$4,382,000
PCON-2: CIPP Lining - No Excavation
Administration (2%)
Construction Management (10%)
Project Total
Subtotal
Engineering (10%)
Environmental (2%)
El Centro 2025 Sewer Master Plan
APPENDIX H: RECOMMENDED CIP PROJECT COST ESTIMATE DETAILS City of El Centro
2025 Sewer Master Plan Update
Project Cost
PCAP-1 Eastside Basin Inflow and Infiltration
Study
Focused I&I study of the Eastside LS tributary area,
including CCTV inspection and smoke testing.
Significant I&I defect flows have been observed at the
Eastside LS sub-basin. In order to avoid unnecessary
upsizing of the sewer collection system, it is
recommended that the infiltration sources be found and
addressed.
$ 466,000
PCAP-2 Main LS Gravity Influent Reconfiguration Reconfigure influent sewer into Main LS wet well and construct separate gravity lines from Villa and Imperial Ave.
Improve conveyance into Main LS wet well and provide
redundancy for Villa and Imperial Ave trunk sewers.
$ 3,849,000
$ 4,315,000
Recommended Capacity Improvement Projects Cost Summary
TOTAL:
Project ID Project Name Description Justification
El Centro 2025 Sewer Master Plan
APPENDIX H: RECOMMENDED CIP PROJECT COST ESTIMATE DETAILS Item No. Item Description Unit Estimated
Quantity Unit Price Item Total
1 Smoke Testing LF 20,000 $3.00 $ 60,000
2 CCTV Inspection LF 80,000 $2.00 $ 160,000
3 TDS Sampling LS 1 $50,000 $ 50,000
Subtotal $ 270,000
General Requirements (10%) $ 27,000
Contingency (30%) $ 81,000
Construction Total: $ 378,000
Soft Costs:
Engineering (15%) $ 57,000
Environmental (6%) $ 23,000
Administration (2%) $ 8,000
Project Total $ 466,000
PCAP-1: Inflow & Infiltration Study
El Centro 2025 Sewer Master Plan
APPENDIX H: RECOMMENDED CIP PROJECT COST ESTIMATE DETAILS Item No. Item Description Unit Estimated
Quantity Unit Price Item Total
1 Construct New 27-inch Pipe and Manholes LF 2,100 $891 $ 1,871,100 2 Main LS Wet Well Modifications EA 1 $50,000 $ 50,000
3 Sewage Bypass and Pumping Plan EA 4 $10,000 $ 40,000
Subtotal $ 1,961,100
General Requirements (10%) $ 197,000
Contingency (30%) $ 589,000
Construction Total: $ 2,748,000
Soft Costs:
Engineering (15%) $ 413,000
Construction Management (15%) $ 413,000
Engineering Services During Construction (2%) $ 55,000
Environmental (6%) $ 165,000
Administration (2%) $ 55,000
Project Total $ 3,849,000
PCAP-2: Main LS Gravity Influent Reconfiguration
El Centro 2025 Sewer Master Plan