Att 1 LOMITA SMP_FINAL_OCTOBER 2024 — Lomita City Council, October 15, 2024

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
OCTOBER 2024
Prepared for:

CITY OF LOMITA
Prepared by:
5 Hutton Centre Drive
Suite 300
Santa Ana, CA 92707

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN

i October 2024

PROJECT STAFF
Project staff participating in the preparation of this Sanitary Sewer System Master Plan includes the following:

Michael Swan, PE, Project Manager; Kim Alexander, PE, Project Engineer; Ben Halbach, PE, Condition Assessment

ACKNOWLEDGEMENTS
Project staff would like to acknowledge the following City of Lomita staff members who provided valuable information and assistance contributing greatly to the successful completion of this project:

Jennifer Howell, PE, Associate Engineer; Carla Dillon, PE, former Public Works Director/City Engineer; Frederic Aboujaoude, PE, Principal Engineer; Brianna Rindge, AICO, former Director of Community & Economic Development

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
ii October 2024

TABLE OF CONTENTS
Chapter Page
Project Staff ......................................................................................................................... i Acknowledgements .............................................................................................................. i

1.0 Executive Summary ................................................................................................ 1-1

1.1 Background ...................................................................................................... 1-1

1.2 Wastewater Collection System Description ..................................................... 1-1

1.3 Flow Monitoring .............................................................................................. 1-2

1.4 Planning Data ................................................................................................... 1-2

1.5 Design Criteria ................................................................................................. 1-2

1.6 Model Development and Calibration ............................................................... 1-3

1.7 Collection System Analysis ............................................................................. 1-3

1.8 Recommended Capital Improvement Program ................................................ 1-4

2.0 Introduction ............................................................................................................. 2-1

2.1 Background and Purpose ................................................................................. 2-1

2.2 Study Area Description .................................................................................... 2-1

3.0 Wastewater Collection System ............................................................................... 3-1

3.1 Description of System ...................................................................................... 3-1

3.2 Current System Conditions .............................................................................. 3-1

4.0 Flow Monitoring ..................................................................................................... 4-1

4.1 Purpose ............................................................................................................ 4-1

4.2 Locations .......................................................................................................... 4-1

4.3 Dry Weather Results ........................................................................................ 4-4

4.4 Wet Weather Flow ........................................................................................... 4-5

5.0 Land Use Planning Data ......................................................................................... 5-1

5.1 Existing Development ...................................................................................... 5-1

5.2 Projected Development .................................................................................... 5-1

5.2.1 Residential Planned Developments....................................................... 5-6

5.2.2 Commercial Redevelopment Areas ...................................................... 5-6

6.0 Model Development and Calibration ...................................................................... 6-1

6.1 Model Construction ......................................................................................... 6-1

6.1.1 Building the Model from GIS ............................................................... 6-1

6.1.2 Sewer Drainage Basins ......................................................................... 6-3

6.2 Dry Weather Calibration .................................................................................. 6-3

6.2.1 Land Use Data Review and Model Loading ......................................... 6-5

6.2.2 Peaking Analysis/Relationship ............................................................. 6-8

6.2.3 Calibration Results ................................................................................ 6-8

6.3 Existing and Projected Flows........................................................................... 6-9

6.3.1 Average Dry Weather Flow .................................................................. 6-9

6.3.2 Peak Dry Weather Flow ...................................................................... 6-11

6.3.3 Design Wet Weather Flow .................................................................. 6-12

7.0 Sewer Design Criteria ............................................................................................. 7-1

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SANITARY SEWER SYSTEM MASTER PLAN
iii October 2024

7.1 Manning’s Coefficient (n) ................................................................................ 7-1

7.2 Design Velocities ............................................................................................. 7-1

7.3 Existing Pipe Flow Depth Criteria (d/D) ......................................................... 7-2

7.4 Recommended Pipe Improvements Criteria .................................................... 7-2

7.5 Sewer Flow Factors.......................................................................................... 7-3

8.0 Collection System Analysis .................................................................................... 8-1

8.1 Existing Scenario ............................................................................................. 8-1

8.2 Buildout Scenarios ........................................................................................... 8-3

9.0 Capital Improvement Plan ...................................................................................... 9-1

9.1 Recommended Capital Improvement Plan Methodology ................................ 9-1

9.2 Existing Collection System Limiting Capacity Areas ..................................... 9-1

9.3 Wastewater Collection System Improvements ................................................ 9-2

9.3.1 PCH to Ebony Capital Improvement .................................................... 9-2

9.3.2 248th Street Capital Improvement ......................................................... 9-6

9.3.3 Oak Street Capital Improvement .......................................................... 9-6

9.3.4 Buildout Limiting Capacity Areas - Watch List ................................... 9-6

9.3.5 CCTV Review and Evaluation.............................................................. 9-7

9.4 Capital Improvement Prioritization and Costs ................................................. 9-7

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
iv October 2024
TABLES
Table 1-1 City Owned Pipeline Summary ................................................................................... 1-2 Table 4-1 Dry Weather Flow Monitoring Results ....................................................................... 4-4 Table 5-1 Existing General Plan Land Use.................................................................................. 5-1 Table 5-2 Acreage by Land Use Designation .............................................................................. 5-3 Table 5-3 Existing and Proposed General Plan Dwelling Units .................................................. 5-5 Table 5-4 Existing and Proposed General Plan Statistics ............................................................ 5-6 Table 6-1 GIS and Model Fields .................................................................................................. 6-2 Table 6-2 Sewer Flow Factors ..................................................................................................... 6-5 Table 6-3 Existing Sewer Flow by Land Use .............................................................................. 6-7 Table 6-4 Dry Weather Flow Calibration Summary.................................................................... 6-8 Table 6-5 Non-Residential Use Flow Factor ............................................................................. 6-10 Table 6-6 Buildout Scenario 1 Loading Factors – Maximum Mixed-Use ................................ 6-10 Table 6-7 Buildout Scenario 2 Sewer Loading – Maximum DUs ............................................. 6-11 Table 6-8 Buildout Sewer Flow Projections .............................................................................. 6-12 Table 7-1 Minimum Slopes by Pipe Size .................................................................................... 7-2 Table 7-2 Sewer Planning Unit Flow Factors .............................................................................. 7-3 Table 8-1 Existing Capacity Watch List Segments ..................................................................... 8-3 Table 9-1 Watch List – Existing Limiting Capacity Areas.......................................................... 9-1 Table 9-2 CIP #1 Improvement Quantities .................................................................................. 9-2 Table 9-3 CIP #2 Improvement Quantities .................................................................................. 9-6 Table 9-4 CIP #3 Improvement Quantities .................................................................................. 9-6 Table 9-5 Watch List – Buildout Limiting Capacity Areas ......................................................... 9-7 Table 9-6 CIP Cost Estimates ...................................................................................................... 9-9

FIGURES
Figure 2-1 Regional Location ...................................................................................................... 2-2 Figure 3-1 Enhanced Maintenance Areas .................................................................................... 3-3 Figure 4-1 Sewer Basins .............................................................................................................. 4-2 Figure 4-2 Flow Monitoring Basins ............................................................................................. 4-3 Figure 5-1 Existing General Plan Land Use ................................................................................ 5-2 Figure 5-2 Proposed General Plan Land Use ............................................................................... 5-4 Figure 6-1 Model Pipelines and Tributary Basins ....................................................................... 6-4 Figure 8-1 Existing Scenario Capacity ........................................................................................ 8-2 Figure 8-2 Buildout Scenario 1 Capacity..................................................................................... 8-4 Figure 8-3 Buildout Scenario 2 Capacity..................................................................................... 8-6 Figure 9-1 Capital Improvement Projects .................................................................................... 9-3 Figure 9-2 Sewer Flow Diversion Improvement ......................................................................... 9-5

APPENDICES
Appendix A – Lomita Sewer Condition Assessment Program Report Appendix B – CCTV Review and Recommendations
Appendix C – US3 Flow Monitoring Report
Appendix D – Model Peaking Curves and Calibration Hydrographs Appendix E – Model Output Data
Appendix F – Harbor Hills Private Sewer System Technical Memorandum

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SANITARY SEWER SYSTEM MASTER PLAN
v October 2024

LIST OF ACRONYMS
ABS Acrylonitrile Butadiene Styrene Pipe
ADU Accessory Dwelling Unit
ADWF Average Dry Weather Flow
BAU Business as Usual
CCTV Closed-Circuit Television
CIP Capital Improvement Program
CSMD Consolidated Sewer Maintenance District
d/D depth of Flow Over Pipe Diameter
EMA Enhanced Maintenance Area
FOG Fats, Oils, and Grease
FM Flow Monitoring
GIS Geographic Information System
gpcd Gallons per Capita per Day
gpd Gallons per Day
gpm Gallons per Minute
I/I Infiltration and Inflow
LF Linear Feet
mgd Million Gallons per Day
San District Los Angeles County Sanitation District
PDWF Peak Dry Weather Flow
RHNA Regional Housing Needs Allocation
SFR Single Family Residential
SMP Sanitary Sewer System Master Plan
VCP Vitrified Clay Pipe
Lomita or City of Lomita
City

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN

1-1 October 2024

1.0 EXECUTIVE SUMMARY

1.1 Background
The City of Lomita (City) is a densely populated urban area of 1.97 square miles (total area is 1,261 acres), located at the base of the Palos Verdes Peninsula in the Los Angeles Basin, 26 miles south of downtown Los Angeles and bounded by the City of Torrance on the north and west, the Harbor Region of Los Angeles to east, and the City of Rolling Hills Estates on the southwest; and the City of Rancho Palos Verdes and unincorporated Los Angeles County area to the southeast.

The City is almost completely developed with mostly residential neighborhoods and commercial uses.

The City’s sanitary sewer collection system serves a population of approximately 20,000 residents and consists of roughly 36 miles of gravity sewer pipelines. The City’s legal authority to own and operate the sanitary sewer system is derived from its incorporation as a City. The City, on June 30, 1964, granted the County of Los Angeles the consent and jurisdiction to annex portions of the sewer system into the Consolidated Sewer Maintenance District (CSMD or County). By that action, the City has entrusted the management, operation, and maintenance of its local sanitary sewer system to the CSMD. The City, however, maintains ownership of the sewer system, and is responsible for ensuring that the public sewer infrastructure is correctly designed, adequately sized, and easily maintained.

The primary objective of the Sanitary Sewer System Master Plan or Sewer Master Plan (SMP) is to develop a hydraulic model of the wastewater collection system (sewer model) and prepare a SMP report for the City of Lomita. The second “S” is left out in the abbreviated title, so it won’t be confused with a Sewer System Management Plan or SSMP, which is a separate report required by the State Water Resources Control Board. The purposes of this report are to summarize the development of the sewer model and prepare a SMP that includes: 1) the capacity evaluation of the City’s wastewater system under existing and future buildout conditions, 2) the existing and future buildout of the City’s wastewater system, and 3) provides recommendations for improvements needed to provide the appropriate level of service under both existing and future buildout conditions. This report contains the planning methodology, criteria, and assumptions used to develop the SMP, as well as the results of the hydraulic modeling and the recommended capital improvement plan for the City’s wastewater collection system. The SMP also includes an overview of ongoing closed-circuit television (CCTV) inspection and condition assessment being conducted by the CSMD on the existing collection system and review of select CCTV provided by the County.

1.2 Wastewater Collection System Description
The existing wastewater collection system consists primarily of vitrified clay pipe (VCP) with a small portion of ABS pipe. The diameters range in size from 6-inch to 15-inch. For the purposes of this analysis, the City’s wastewater collection system has been prioritized to model primary collection pipelines that serve large tributary basins and areas of future development. The remaining pipelines may be added to the model as needed for analysis of specific future development. Information on the total length of City pipelines by diameter and pipe material is provided in Table 1-1.

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
1-2 October 2024
Table 1-1
City Owned Pipeline Summary
Diameter
(in) Material Length (ft)
8 ABS 919
6 VCP 37
8 VCP 180,972
10 VCP 5,189
12 VCP 3,015
15 VCP 607
Total 190,736
Wastewater generated within the system flows by gravity to the Los Angeles County Sanitation District (San District) trunk sewers directly, or in some cases through Los Angeles/Harbor City and City of Torrance sewers. These trunk sewers route the flow to the San District’s A.K. Warren Water Resource Facility (formerly the Joint Water Pollution Control Plant) in Carson. Existing average dry weather flow generated within the City’s service area is estimated to total 1.61 million gallons per day (mgd) with buildout flow estimated at 2.31 mgd.

1.3 Flow Monitoring
As a part of this SMP, flow monitoring was conducted by US3 during a 15-day period from November 7 to November 21, 2023, at three locations. The primary purpose of this flow monitoring program was to measure and determine the relative flow from different areas of the wastewater collection system. The flow measurement data collected during the flow monitoring program established a benchmark for sewer model calibration and estimating peak dry weather flow (PDWF) conditions.

1.4 Planning Data
The City of Lomita wastewater collection system has approximately 8,900 service connections.

The majority of these customer connections are residential. Based on the composite land use within the City’s sewer service area by acreage, the land use is comprised of 73% residential, of which 52% is low density, 11% commercial, 1% industrial/manufacturing, 9% publicly owned land, and 6% mixed-use, excluding right-of-way. For planned developments, information provided by the City Planning Department was used to estimate buildout land use and population for the sewer system. Planned land use is based on the City’s Preferred Land Use Plan (November 2023) developed as part of proposed updates to the General Plan.

1.5 Design Criteria
Sewer pipe capacities are dependent upon many factors. These include the roughness of the pipe, the chosen maximum allowable depth of flow, and limiting velocity and slope. The Continuity Equation and the Manning’s Equation for steady state flow are used for gravity sewer hydraulic calculations.

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
1-3 October 2024
The capacity criteria for gravity sewers are typically evaluated by a ratio of flow depth over pipe diameter (d/D). Existing sewers for this analysis were evaluated so the d/D ratios (specified below) are not exceeded while flowing under the PDWF conditions:
15-inch and larger d/D greater than 0.75
12-inch and smaller d/D greater than 0.67
Recommended replacement diameters for pipeline segments identified as capacity deficient are based on the following design criteria under PDWF conditions:
15-inch and larger – d/D less than or equal to 0.60
12-inch and smaller – d/D less than or equal to 0.50

1.6 Model Development and Calibration
As part of the SMP, a hydraulic model of the wastewater collection system (sewer model) was constructed from the County’s CSMD sewer Geographic Information System (GIS) geodatabase.

The hydraulic modeling software identified for the computer model is InfoSewer, which runs inside of Esri’s ArcGIS Software.

The average dry weather flows (ADWF) were allocated and calibrated in the wastewater model based upon land use data and the results of a flow monitoring program conducted from November 7 to November 21, 2023.

Peak dry weather flows were determined using a peaking curve which was developed based on an analysis of the average and peak dry weather flows monitored during the flow monitoring program.

The results of the flow calibration are similar to those observed in the City’s system under dry weather conditions.

1.7 Collection System Analysis
The City’s existing wastewater collection system was evaluated using land use data to generate flows. These flows were then calibrated to the wastewater flow monitoring data and compared to existing pipeline system capacity using the analysis criteria discussed above.

An analysis of the existing condition identified sufficient capacity within the existing collection system. A “watch list” was created for pipelines approaching the capacity criteria limit under existing peak flow conditions. Additional development upstream of these segments may result in flows that exceed pipeline capacities.

Buildout conditions were developed in coordination with the City Planning Department and consider proposed updates to the City’s General Plan and accommodates the 6th Cycle Housing Element Update. The City has developed a Preferred Land Use Plan in the process of updating its General Plan. The Preferred Land Use Plan will accommodate growth over the next twenty years primarily through mixed-use development where new homes can be developed close to goods, services, and transportation facilities. The City’s Preferred Land Use Plan has been used in this analysis to develop buildout sewer flow projections. These parameters are discussed in more detail in Chapter 5.

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
1-4 October 2024
Two model scenarios were developed to evaluate system buildout conditions using planning data provided in the Preferred Land Use Plan. Under buildout conditions, three improvement areas were identified, comprised of 19 capacity deficient pipeline segments (manhole to manhole) in the existing collection system. The deficient pipelines total approximately 3,400 linear feet (LF) in length.

1.8 Recommended Capital Improvement Program
The Capital Improvements Projects (CIPs) established in this SMP are provided to the City as recommended solutions to address future wastewater collection system areas identified for capacity enhancements discovered using the above methodologies, and as described in more detail later in this SMP. The following wastewater collection system improvement projects are recommended for implementation to provide sufficient capacity for buildout developments within the study area:

1. Abandon the 10-inch pipeline running along the back yards between Pacific Coast Highway (PCH) and Ebony and direct tributary flow to a new 15-inch replacement pipeline along Walnut and Ebony. Construct new 8-inch pipelines along side streets to direct sewer flow from areas served by the abandoned pipeline toward the new pipeline. A flow diversion alternative is also provided as a near-term solution to reduce sewer flows to the capacity deficient pipelines.

2. Replace pipeline on 248th Street (MH016 to MH017) to correct sag in existing pipeline.

The pipeline sag was identified by the CSMD and results in high water levels and frequent cleaning.

3. Correct flat slope along Oak Street (MH386 to MH388) by replacing pipe along with adjacent segments.

CIP #1 above corrects approximately 2,800 LF of deficient pipeline aligned through back yards with 9,800 LF of pipeline located within roadways, including new pipelines to redirect flows. This CIP will require long-term planning, including a preliminary design level analysis to determine project feasibility. As such, an alternative is provided to divert flow to the San District trunk sewer along Western Avenue, upstream of the modeled deficient pipelines, to increase the available pipeline capacities.

CIP #2 corrects a segment with a sag identified by the CSMD that results in observed high water marks and frequent cleaning. This segment is modeled with sufficient capacity under buildout conditions using the existing 8-inch diameter pipeline. CIP #3 corrects a flat segment (136 LF) by replacing that segment and the two adjacent segments for a total replacement length of 600 LF.

These capacity enhancement areas, and the recommended capital improvement projects, are described in more detail in Chapter 9, with capital cost estimates in 2024 dollars summarized in Table 9-6. The project costs include estimated construction costs plus 45% for Professional Services and Contingencies (15% for design and technical services; 10% for administration, construction management, inspection, and project administration; and 20% for contingencies).

The recommended CIPs are proposed to correct the areas identified for capacity enhancement and structural issues with combined estimated project costs of approximately 9 million dollars. Though the deficient pipelines total 3,400 LF, the CIPs total 10,700 LF.

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN

2-1 October 2024

2.0 INTRODUCTION

2.1 Background and Purpose
The City of Lomita sanitary sewer collection system serves a population of approximately 20,000 residents and consists of roughly 36 miles of gravity sewer lines. The City’s legal authority to own and operate the sanitary sewer system is derived from its incorporation as a City. The City, on June 30, 1964, granted the County of Los Angeles the consent and jurisdiction to annex portions of the sewer system into the Consolidated Sewer Maintenance District (CSMD). By that action, the City has entrusted the management, operation, and maintenance of its local sanitary sewer system to the CSMD. The City, however, maintains ownership of the sewer system, and is responsible for ensuring that the public sewer infrastructure is correctly designed, adequately sized, and easily maintained.

The purpose of the Sanitary Sewer System Master Plan is to analyze and assess the City’s existing sewer infrastructure to address capacity deficiencies in the system. Deficiencies are identified and prioritized in a specific list of projects that looks to replace, rehabilitate, and maintain the sewer facilities and infrastructure. As part of the project, a GIS-based hydraulic model of the City’s sewer collection system was developed to identify and evaluate areas for capacity enhancement and capital improvement needs for existing and future flow conditions.

This report presents the temporary flow monitoring program, planning methodology, design criteria, and assumptions used to develop the SMP, as well as the results of the hydraulic modeling and the recommended Capital Improvement Program (CIP) for the City‘s sewer collection system.

2.2 Study Area Description
The City of Lomita is an urban, densely populated 1.97 square mile area (total area is 1,261 acres), located at the base of the Palos Verdes Peninsula in the Los Angeles Basin, Los Angeles County, 26 miles south of downtown Los Angeles. The City is bounded by the City of Torrance on the north and west, the Harbor Region of Los Angeles to east, and the City of Rolling Hills Estates on the southwest; and the City of Rancho Palos Verdes and unincorporated Los Angeles County area to the southeast, as illustrated on Figure 2-1. The City is almost completely developed with mostly residential neighborhoods and commercial units. The majority of land use is residential with commercial uses primarily centered along three major corridors: Pacific Coast Highway, Narbonne Avenue, and Lomita Boulevard.

Topography within the City varies from about 50 feet above sea level to a high of about 360 feet above sea level and slopes gradually toward Lomita Boulevard and east toward the Harbor Region of Los Angeles giving sufficient changes in elevation to allow gravity flow throughout the sewer system to the San District trunk lines for ultimate collection, treatment, and disposal.

Carson
Torrance
Los Angeles
Rancho Palos Verdes
Redondo Beach
Lomita
Los Angeles
Rolling Hills
Gardena
Palos Verdes Estates
Compton
Rolling Hills Estates
Manhattan Beach Lawndale
Alondra Park
West Carson
Hermosa Beach
Long Beach
West Rancho Dominguez
Long Beach
Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
Figure 2-1
Regional Location

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SANITARY SEWER SYSTEM MASTER PLAN

3-1 October 2024

3.0 WASTEWATER COLLECTION SYSTEM

3.1 Description of System
The existing wastewater collection system consists primarily of VCP with a small portion of ABS pipe. The gravity pipeline diameters range in size from 6-inch to 15-inch. The City owns approximately 36 miles of gravity pipeline and 900 manholes.

Wastewater generated within the system flows by gravity to the Los Angeles County Sanitation District trunk sewers located along Narbonne Avenue, 250th Street, Lomita Boulevard, Eshelman Avenue, and Western Avenue as shown on Figure 3-1. These trunk sewers route the flow to the existing A.K. Warren Water Resource Facility (formerly known as the Joint Water Pollution Control Plant) located in the City of Carson. The treatment plant has a capacity of 400 mgd and currently processes an average flow of 243 mgd.

3.2 Current System Conditions
The oldest portions of the collection system were constructed in the 1930s and are located throughout the City. From a structural and maintenance perspective, the most basic information needed for a wastewater collection system is the condition of the sewer pipe. The most useful tool in assessing the condition of a sewer pipe is closed-circuit television (CCTV) inspection. Sewer inspection is conducted by the CSMD along with maintenance and repairs. The CSMD performs CCTV inspections and rates the structural integrity and maintenance condition of all sewers in its service area on a 10-year cycle (approximately 500 miles of sewer infrastructure each year) and provides a Condition Assessment Program Report for each member city and unincorporated areas in Los Angeles County. The last Condition Assessment Program Report for the City of Lomita system is dated February 5, 2019, and is included in Appendix A. The report documents the review of CCTV inspection for 100 percent of the City’s sewer system that took place in 2013 and provides pipeline grading based on observed defects. The CSMD completed the latest CCTV inspection between April and December 2021 but, currently, the Condition Assessment Program Report has not been completed. The CSMD expects the completed report to be available later this year.

The current problem areas within the wastewater collection system were identified by County maintenance staff. County staff indicated that these areas require maintenance on a more frequent, regular basis within the wastewater collection system. These are referred to as enhanced maintenance areas (EMA) or hot spots and include areas of regular fat, oil, and grease (FOG) buildup and root intrusion. The EMAs provided by the CSMD are illustrated on Figure 3-1. The exhibit is color coded for the type of maintenance: hydro or rodder cleaning. Hydro cleaning is typically used for areas of frequent FOG buildup or pipelines with sags while rodder cleaning occurs in areas that have physical obstructions such as roots. FOG buildup is a regular occurrence due to restaurant uses that can be mitigated with frequent cleaning. Roots can indicate structural damage in the pipe and may be mitigated with root treatment and pipeline repair or replacement.

Areas identified for maintenance improvements are typical of systems of similar age that include root intrusion and cracks.

As part of this master plan, a detailed pipeline assessment was performed for strategically identified CCTV-inspected sewer pipe segments available from the County. The assessment included the 10-inch VCP aligned outside of roadways and through developed properties from

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
3-2 October 2024
Pacific Coast Highway to Ebony Lane (between and parallel to Western Avenue and Walnut Street). This pipeline has a large tributary area and the sewer plans (C.I. No. 1003) are dated 1934, making this pipeline 90 years old. Based on the review, Psomas developed a recommended rehabilitation method along with a justification/rationale for each sewer segment and included in Appendix B. The recommendations consisted of performing point repairs, lining sewer segments in between existing manholes, lining sewer sections, or a combination of methods. As discussed later in Section 8.2, these segments were also identified as capacity deficient under buildout conditions.

Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
Legend
Hydro Maintenanced Area
City Pipe
Rodder Maintenanced Area Figure 3-1
Enhanced Maintenance Areas
Back Yard Pipe
248th St. Narbonne Ave.

Lomita Blvd.

Pacific Coast Hwy. Appian Way Cayuga Ave.
242nd St. Cypress St.

LA County San District Pipe

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SANITARY SEWER SYSTEM MASTER PLAN

4-1 October 2024

4.0 FLOW MONITORING

4.1 Purpose
The primary purpose of the flow monitoring program was to measure and determine the relative flow from different areas of the wastewater collection system. The flow measurements collected in the flow monitoring program established a benchmark for wastewater model calibration. US3 was retained as a sub-consultant to conduct a temporary flow monitoring study of the wastewater collection system at three separate locations. The sites were monitored during a 15-day period from November 7 to November 21, 2023. The report captures the average dry weather flow (ADWF) and peak dry weather flow (PDWF) within the monitored basins.

4.2 Locations
Figure 4-1 illustrates the various sewer basins within the City’s system. Each basin collects City sewer flows and discharges to Los Angeles County Sanitation District at a single outlet manhole located at the downstream end of the basin, or at two locations, or into neighboring cities. The individual flow monitoring site locations were chosen to collect flow measurements within major tributary basins illustrated on Figure 4-2. Figure 4-2 shows the area tributary to each flow monitoring location in a different color, illustrating the catchment area for these sites.

The monitoring locations and resulting sewer basins were selected to capture a significant portion of the service area flow while utilizing a limited number of flow monitoring sites. Flow monitoring selection can be based on capturing a specific land use type to develop flow factors. The sewer basins within the City, however, are all comprised of primarily residential land uses with a small percentage of commercial uses tributary to the same collection system. This is representative of the City’s land use as a whole. The major commercial corridors of Pacific Coast Highway, Narbonne Avenue, and Lomita Boulevard contribute flow to numerous sewer basins with much of the flow from Narbonne Avenue and Lomita Boulevard discharging directly, or through a limited number of collection pipelines, to Los Angeles County Sanitation District pipelines. City land use by type is discussed later in Section 5.1 and illustrated on Figure 5-1. Since non-residential uses contribute a small percentage of the flow, those factors may be established using typical loading criteria for the various use types. Additionally, sewer generation for non-residential uses vary by use type, making this approach very reasonable. Basins 1 and 2, illustrated on Figures 4-1 and 4- 2, are the largest sewer basins within the City and collect some commercial flow from Pacific Coast Highway. Basin 3 also has a large tributary area and collects sewer flow from portions of the City’s two major corridors of Narbonne Avenue and Lomita Boulevard. The three flow monitoring basins generate approximately 40% of the City’s sewer flow by volume.

Study area sewer pipelines not captured through flow monitoring will be modeled using the same calibrated flow factors estimated based on data gathered from the three monitored locations along with typical land use flow factors.

Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
Model Manhole - Complete Data
Model Pipe - Complete Data
Model Pipe - No Invert Data
City Outfall
Color Coded Basins
250th St. 248th St.

Lomita Blvd.

Pacific Coast Hwy. Eshelman Ave. Pennsylvania Ave. Cypress St. Oak St. Back Yard Pipe Ebony Ln.

Figure 4-1
Model Pipelines and Sewer Basins
Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
City Parcels
FM Basin 1
FM Basin 2
FM Basin 3
Flow Monitoring Site
Site #1 Site #2 Site #3 250th St. 252nd St.
248th St. Narbonne Ave.

Lomita Blvd.

Pacific Coast Hwy. Figure 4-2
Flow Monitoring Sites and Basins City Outfall

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SANITARY SEWER SYSTEM MASTER PLAN
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4.3 Dry Weather Results
The results of the temporary flow monitoring program are presented in data summary reports for each site. These reports were prepared by US3 and provide flow summaries including average, minimum and maximum depth, velocity, and flow information; quantity hydrographs; and daily log tables for the metering period. Flow monitoring data was recorded in 5-minute time intervals and provided in Excel files. The complete flow monitoring report is included in Appendix C.

Table 4-1 summarizes the flow monitoring data, presenting the average and peak flows for each day in the monitoring period, the ratios of peak to average flows for each day, and the study period averages. Weekday and weekend flow comparisons were made but no significant differences were found. Overall, the average flows were used to calibrate the model flow factors by land use type for each basin. Flow peaking is developed using diurnal peaking factors based on the flow monitoring data.

Table 4-1
Dry Weather Flow Monitoring Results
Day
FM SITE 1 - 250th STREET FM SITE 2 - 252nd STRETT FM SITE 3 - 248th STREET Avg
(gpm)
Max
(gpm) Factor
Avg
(gpm)
Max
(gpm) Factor
Avg
(gpm)
Max
(gpm) Factor
7-Nov 151.1 246.7 1.63 207.0 305.1 1.47 76.1 118.8 1.56 8-Nov 147.4 230.8 1.57 214.4 318.8 1.49 68.5 105.4 1.54 9-Nov 140.8 215.4 1.53 191.8 293.3 1.53 68.7 105.7 1.54 10-Nov 153.5 255.2 1.66 200.2 326.0 1.63 71.6 121.1 1.69 11-Nov 144.2 248.5 1.72 214.0 339.4 1.59 65.4 110.7 1.69 12-Nov 147.4 230.0 1.56 218.4 370.0 1.69 69.1 116.9 1.69 13-Nov 124.7 197.4 1.58 206.2 305.0 1.48 67.9 98.9 1.46 14-Nov 130.6 212.9 1.63 203.6 334.5 1.64 68.5 104.8 1.53 15-Nov 137.1 265.2 1.93 206.5 321.1 1.55 69.2 111.0 1.61 16-Nov 176.7 259.9 1.47 202.7 293.0 1.45 69.8 111.5 1.60 17-Nov 175.4 256.1 1.46 195.0 301.1 1.54 68.4 103.1 1.51 18-Nov 149.1 233.7 1.57 205.5 322.2 1.57 69.0 108.5 1.57 19-Nov 149.2 225.4 1.51 208.3 337.3 1.62 67.6 113.7 1.68 20-Nov 136.8 199.3 1.46 199.5 316.4 1.59 70.1 107.8 1.54 21-Nov 136.4 191.4 1.40 197.1 316.4 1.61 67.2 108.8 1.62 Avg/Peak 146.7 265.2 1.81 204.7 370.0 1.81 69.1 121.1 1.75 Avg/Peak
Weekday 148.2 265.2 1.79 202.9 339.4 1.67 69.4 121.1 1.75 Avg/Peak
Weekend 142.6 233.7 1.64 209.6 370.0 1.77 68.4 116.9 1.71

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4-5 October 2024

4.4 Wet Weather Flow
Wet weather flows are the result of infiltration and inflow (I/I). Infiltration is water other than wastewater that enters the collection system from the groundwater around the pipe zone due to defective pipes, pipe joints, service connections, or manholes and frequently improperly laid house or service laterals (per National Clay Pipe Institute). Inflow is water that enters the system from sources such as area drains, manhole covers, cross connections from storm drains and/or catch basins (illegal), surface runoff, or drainage. The effects of inflow on wastewater flow can generally be seen during or immediately following a storm event, whereas the effects of infiltration typically develop slower and tend to lag a storm event. The flow monitoring program was conducted during a dry season and did not capture wet weather events. Based on the CSMD Condition Assessment Program Report (2019), CCTV inspection revealed that infiltration was not detected in any pipe segments in the City's system. Regardless, sewer design criteria, discussed in Chapter 6, is established to allow capacity for wet weather flows.

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN

5-1 October 2024

5.0 LAND USE PLANNING DATA

5.1 Existing Development
The City of Lomita General Plan Update Preferred Land Use Plan (November 2023) reports an existing population of approximately 21,843 and 8,274 dwelling units, with an average household density of 2.64 people per dwelling unit. The CSMD reported 8,908 total sewer service connections in the latest Sewer System Management Plan (SSMP) adopted in 2018, including commercial and combined service to multi-family units. Existing General Plan land use designations and existing land use by parcel was provided by the City in GIS format. The City indicated that the existing land use by parcel represents Los Angeles County data and is currently the best information available on parcel-based land use. General Plan Land Use has been categorized into residential and non-residential uses as summarized in Table 5-1, along with existing acreage by land use designation. Figure 5-1 depicts the location of these land uses within the City. Excluding right-of-way area within the City, the land use by area is comprised of 72.7% residential, of which 51.6% is low density, 10.8% commercial, 1.4% industrial/manufacturing,

9.5% publicly owned land, and 5.6% mixed-use.

Table 5-1
Existing General Plan Land Use
General Plan Land Use Designation Acres % of Total
Residential Use 712 72.7%
Agricultural 90 9.2%
Low Density 506 51.6%
Medium Density 66 6.7%
High Density 50 5.1%
Non-residential Use 268 27.3%
Commercial 106 10.8%
Mixed-Use 55 5.6%
Industrial/Manufacturing 14 1.4%
Publicly Owned Land 93 9.5%
TOTAL DEVELOPMENT USES 980
Right-of-Way (ROW) 243
TOTAL WITH ROW 1,223
SOURCE: Lomita General Plan Update Preferred Land Use Plan, November 2023

5.2 Projected Development
The City expanded substantially in the 1980s and 1990s but has only experienced very mild development in recent years. The City is mandated by California State Law to prepare a Housing Element update for State certification. Lomita is expected to provide a minimum of 829 new units for its Regional Housing Needs Allocation (RHNA) for the 2021-2029 Housing Element Cycle.

Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
Mixed Use Overlay
Residential (High Density)
Residential (Medium Density)
Residential (Low Density)
Residential (Agricultural)
Commercial
Downtown Overlay
Industrial/Manufacturing
Publicly Owned Land
Figure 5-1
Existing General Plan Land Use
City Outfall

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5-3 October 2024
To accommodate future growth, the City is updating its General Plan and has prepared a Preferred Land Use Plan as part of the update process. The Land Use Plan provides data on existing development, buildout development under the current General Plan (designated as “Business as Usual”), and buildout development under the proposed General Plan update. Existing population within the City is 21,843. Buildout of the existing City General Plan results in a projected population of 23,616 while buildout of the Preferred Land Use Plan ranges from a population of 28,430 to 29,224, or a 20% to 22% increase from the existing General Plan. The City also provided the Preferred Land Use Plan data in GIS format.

Table 5-2 identifies the distribution of acreage in the City by land use designation under the Preferred Land Use Plan compared to no change in General Plan land use, or “Business as Usual”.

As shown in Table 5-2, the Preferred Land Use Plan proposes to change commercial, industrial, and high-density residential land uses to various densities of mixed-use designations, thus allowing for increased housing. The various mixed-use designations are distinguished by the allowed residential densities, with the number provided in the designations (Mixed-Use 30, Mixed-Use 40, etc.) representing the maximum allowed dwelling units per acre. The Land Use Plan includes two options for the maximum mixed-use density, the first called Mixed-Use 60 (MU 60), allowing up to 60 dwelling units per acre and the second called MU 70, allowing up to 70 dwelling units per acre. Proposed General Plan Land Use is illustrated on Figure 5-2.

Table 5-2
General Plan Acreage by Land Use Designation
Land Use Designation Business as Usual
(No Change)
Preferred Land Use
Plan
Residential Development Use
Agricultural 90 90
Low Density 506 504
Medium Density 66 63
High Density 50 14
Nonresidential Development Use
Commercial 106 3
Mixed-Use - 22 55 0
Mixed-Use - 30 - 13
Mixed-Use - 40 - 144
Mixed-Use - 60/70 - 68
MCMU(1) – 40 - 8
MCMU(1)- 60/70 - 7
Industrial/Manufacturing 14 0
Publicly Owned Land 93 66
Right-of-Way 243 243
TOTAL 1,223 1,223
(1) Manufacturing-Commercial Mixed-Use (MCMU) may include industrial use.

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SANITARY SEWER SYSTEM MASTER PLAN
5-5 October 2024
Table 5-3 identifies the projected buildout of residential units by land use designation under the Preferred Land Use Plan compared to Business as Usual. Up to 4,298 dwelling units are added as part of the proposed mixed-use designations, well above the RHNA requirement of 829 units. At the same time, the number of dwelling units under the existing General Plan residential designations are projected to decrease by 1,566 units, marking a shift of residential units to the new mixed-use designations. The number of dwelling units projected within the new mixed-use designations is a key residential growth number used later in sewer flow projections.

Table 5-3
Existing and Proposed General Plan Dwelling Units

Business as Usual (No
Change)
Preferred Land Use
Plan (MU 60)
Preferred Land Use
Plan (MU 70)
Total
Units
Percent
of Total
Total
Units
Percent
of Total
Total
Units
Percent
of Total
Residential Designations 8,337 93% 6,771 63% 6,771 61%
Agricultural 785 9% 782 7% 782 7%
Low Density 4,410 49% 4,390 41% 4,390 40%
Medium Density 1,181 13% 1,127 10% 1,127 10%
High Density 1,961 22% 472 4% 472 4%
Mixed-Use Designations 608 7% 3,996 37% 4,298 39%
Mixed-Use - 22 608 7% 0 0% 0 0%
Mixed-Use - 30 - 0% 141 1% 141 1%
Mixed-Use - 40 - 0% 2,026 19% 2,026 18%
Mixed-Use - 60/70 - 0% 1,574 15% 1,846 17%
MCMU(1)- 40 - 0% 105 1% 105 1%
MCMU(1)- 60/70 - 0% 150 1% 180 2%
Total 8,945 - 10,767 - 11,069 -
(1) Manufacturing-Commercial Mixed-Use (MCMU) may include industrial use.

Table 5-4 provides total dwelling units, population, and non-residential square footage from the Preferred Land Use Plan, for the densest MU 70 option, compared to existing development and Business as Usual (BAU). Based on Table 5-2, non-residential uses are being transferred from existing Commercial, Industrial, and an existing MU 22 designation to the new mixed-use designations. Therefore, the Preferred Land Use Plan non-residential square footage of 3.23 million square feet, shown in Table 5-4, will primarily occur within these new designations. The projected non-residential square footage is a key value that represents the growth and buildout of non-residential uses. Also noted in Table 5-4, the single-family residential units and population are projected to increase by 2 percent. Because the new mixed-use designations allow for higher residential densities, this growth is assumed to be attributed to accessory dwelling units (ADUs) added to existing single-family residential parcels.

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SANITARY SEWER SYSTEM MASTER PLAN
5-6 October 2024
Table 5-4
Existing and Proposed General Plan Statistics
Existing
Development
Business as Usual
(No Change)
Preferred Land Use Plan Mixed-Use 70
Total Change
from BAU
% Change
from BAU
Units 8,274 8,945 11,069 2,124 24%
Single-Family 4,777 5,261 5,371 110 2%
Multifamily 3,497 3,685 5,698 2,013 55%
Population 21,843 23,616 29,224 5,608 24%
Single-Family 12,611 13,888 14,181 293 2%
Multifamily 9,232 9,727 15,043 5,316 55%
Non-residential
Square Feet 2,527,297 2,635,158 3,228,048 592,890 22%
Jobs 3,036 3,217 4,034 817 25%
The various mixed-use areas are designated with a maximum residential density, or maximum number of dwelling units per acre. Non-residential use is designated a maximum FAR (floor to parcel area ratio) of 1:1 (one to one). For projects which include residential and non-residential components, the density requirements apply to the residential component and the FAR requirements apply to the non-residential component. Single-use projects are also allowed.

5.2.1 Residential Planned Developments
As illustrated on Figure 5-2, the Proposed General Plan Land Use redevelopment areas consist of mixed-use designations along the major corridors of Pacific Coast Highway, Narbonne Avenue, Lomita Boulevard, and Western Avenue.

These areas are currently designated for various commercial uses. Increased housing is primarily met by these new mixed-use designations. The RHNA also identifies the potential for additional housing on currently underutilized sites and Accessory Dwelling Units (ADUs) constructed on existing single family residential lots. As noted above, the single-family residential units and population are projected to grow by 2 percent. This growth is assumed to be attributed to accessory dwelling units added to existing single-family residential parcels.

5.2.2 Commercial Redevelopment Areas
The City’s Preferred Land Use Plan replaces (changes) much of the currently designated commercial use to mixed-use, allowing both residential and commercial uses. The proposed change to the General Plan provides a total non-residential use area of 3.23 million square-feet, or an additional 700,000 square-feet above buildout of the existing General Plan. Non-residential use is assumed to occur within the existing non-residential areas that will become mixed-use as a part of the proposed General Plan Update.

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN

6-1 October 2024

6.0 MODEL DEVELOPMENT AND CALIBRATION

6.1 Model Construction
The wastewater collection system hydraulic model was constructed for the City from the CSMD’s most recent sewer GIS. The hydraulic modeling software utilized for the computer model is InfoSewer, which runs inside of ArcGIS.

6.1.1 Building the Model from GIS
A hydraulic model was developed to include the tributary wastewater collection facilities provided in CSMD’s Sewer GIS. In addition to facility locations, the GIS data includes pipeline lengths and diameters; however, no pipeline invert data was provided.

Populating pipeline invert data for the entire collection system requires a complete review of sewer pipeline as-built plans and is a time-consuming effort. Given limited City resources at this time, populating every system pipe with invert data was not possible within the current modeling effort.

As such, targeted tributary basins were selected that collect from large areas and represent backbone pipelines within the collection system. Smaller tributary basins and reaches of pipelines that feed into these selected systems are less likely to experience capacity deficiencies due to lower flow. If the upstream pipelines in the modeled systems are not deficient, it is likely that the unmodeled pipelines located farther upstream of and tributary to these systems will also not be deficient, given the same diameter and assuming similar pipeline slopes. The modeling approach is to evaluate these select pipelines and then evaluate if the analysis should move farther upstream.

All system pipelines have been included within the hydraulic model so, ultimately, invert data may be added to the remainder of the system as resources become available.

Model pipeline and manhole data was imported from the CSMD Sewer GIS. The “GIS Gateway” import tool is integrated within the InfoSewer wastewater modeling software and was used to link GIS elements with the hydraulic model. Table 6-1 presents a list of the required and the optional fields for each model element with the corresponding GIS feature class fields. The information in Table 6-1 provided the basis for data mapping between the GIS and hydraulic model. Not all information necessary for hydraulic modeling was included in the GIS as identified in Table 6-1 and described below. The GIS manholes and pipelines are named using identification numbers within the CSMD GIS labeled as “MMS”.

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SANITARY SEWER SYSTEM MASTER PLAN
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Table 6-1
GIS and Model Fields

GIS SEWER MODEL
Field Field Required Optional
Gravity Mains
MMS Model ID x
P_LENGTH Length x
DIAMETER Diameter x
n/a From Invert x
n/a To Invert x
n/a Start Node x
n/a End Node x
n/a Roughness x
MATL Material x
n/a Slope x
JUR Owner x
n/a Drawing x
n/a Yr_Inst x
Manholes
MMS Model ID x
n/a Diameter x
n/a Rim_Elev x
n/a Yr_Inst x
n/a = Data not available in the CSMD GIS
The following information was not included in the GIS and was populated in the model after initial import:
• Invert Elevation - Invert elevation was not entered in the pipeline data in GIS. The invert elevation in the model was populated for select backbone pipelines using sewer as-built plans.
• Manhole Diameter - Diameter information was not available for manholes in the GIS. A diameter of 4-feet was assigned in the model to all manholes based on standard size (48” diameter manhole).
• Manhole Rim Elevation – Manhole rim elevation data was not available in the GIS. Rim elevations for the selected modeled basins were input using sewer as-built plans. • Missing Manhole Data – Pipeline data in GIS is missing the upstream and downstream manhole number in the data fields. Pipelines were connected to the adjacent upstream and downstream manholes using model connectivity tools.
• Based on the age of the system and County assessment, pipe Manning’s coefficients (n values) were conservatively set equal to 0.015 in the hydraulic model.

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• Outlet manholes were placed at the furthest downstream tributary reach of each basin at the terminus of a system. The intent of this manhole is to be the final collection point for discharge from the City collection system. The outlet manholes consist of all locations where the City system connects to a non-District sewer pipeline, in most cases a Los Angeles County Sanitation District trunk sewer.

After the initial import of GIS data was completed, additional work was accomplished within the model to make the networks hydraulically complete and representative of the existing system. In entering pipeline invert elevation from as-built plans, pipeline diameter data in the GIS was found to be inconsistent with as-built plans for several reaches of pipelines. The CSMD was contacted and informed of the discrepancies. It was confirmed that the as-built data was correct so it was utilized in the model and the CSMD subsequently updated their GIS data.

The resulting model pipelines are illustrated in Figure 6-1. The pipelines that were populated with upstream and downstream invert elevation data and the corresponding tributary flow basins are also identified on Figure 6-1.

6.1.2 Sewer Drainage Basins
A total of 29 manholes were classified as outlets for 29 model basins. The tributary drainage basins by outfall are illustrated on Figure 4-1. The outlet manhole type is placed at the furthest downstream tributary portion of a reach of pipeline, at the terminus of a system. The intent of the outlet manhole is to represent the final collection point or point of disposal. The outlet manholes primarily consist of locations where the City’s system connects to a San District pipeline that is not in the model. Some parcels discharge directly to the San District and were not designated within a sewer basin. The outlet manholes discharging to the San District are located along Lomita Boulevard, Narbonne Avenue, 250th Street, Eshelman Avenue, and Western Avenue. There are two basins that discharge to other cities, one to Los Angeles and the other to Torrance.

6.2 Dry Weather Calibration
Calibration of any hydraulic model is an important part of modeling. Calibration usually determines the validity of the model results as compared to field data. The City’s wastewater model was calibrated to establish a level of confidence in the flows it simulates.

Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
Model Manhole
Model Pipe - Complete Data
Model Pipe - No Invert Data
City Outfall
Color Coded Tributary Basins
Other Basins
250th St. 248th St.

Lomita Blvd.

Pacific Coast Hwy. Pennsylvania Ave. Cypress St. Oak St. Eshelman Ave. Back Yard Pipe Ebony Ln.

Figure 6-1
Model Pipelines and Tributary Basins

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6-5 October 2024

6.2.1 Land Use Data Review and Model Loading
Average dry weather flows were allocated and calibrated in the model using flow factors based on the land use data in GIS by parcel provided by the City, the current flow monitoring data, and the flow monitoring tributary areas. The land uses in the GIS data were initially used when determining flow factors. An iterative, trial and error method was used within Excel to select flow factors to match average flow monitoring data as close as possible. Flow factors were varied up and down within typical ranges observed for residential, commercial, industrial, and institutional land use categories.

During this exercise it became apparent that monitored flow for Basin 2 appeared to be high for the land uses within that basin. Additional research of as-built plans was conducted on the tributary area and it was determined that the 301-unit Harbor Hills Housing property was tributary to Basin 2 while the CSMD mapping illustrated this area flowing away from the basin. The Basin 2 model loading was adjusted to include all units within the Harbor Hills property resulting in model flows that calibrated closely to observed flows using the calibrated factors.

Table 6-2 shows the model flow factors by land use type for the City’s system. The flow factors are in gallons per day (gpd) per dwelling unit (du) for residential uses and gpd per acre for commercial, institutional, and industrial uses. Average calibrated modeled flows by land use type for each of the three flow monitoring basins are included in Appendix D.

The land use data, stored in a polygon shape file, and calibrated flow factors were used to calculate sewer loads for each parcel. Using ArcGIS tools, the City parcel data was assigned to a point feature and loaded to the closest upstream model manhole. Further manual verification was conducted to verify that each parcel data point was allocated to the proper manhole in each basin.

Table 6-2
Sewer Flow Factors
Land Use Type and Description Flow Factor (gpd/du)
Residential
Five or more apartments 100
Four Units (Any Combination) 100
Three Units (Any Combination) 110
Two Units 140
Multi-Family 160
Single 210
Mobile Home Parks 100

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Table 6-2 (cont.)
Flow Factors
Land Use Type and Description Flow Factor (gpd/ac)
Commercial
Auto, Recreation EQPT, Construction EQPT, Sales & Service 1,000 Banks Savings & Loan 1,500
Commercial 1,500
Hotel & Motels 1,500
Office Buildings 1,500
Restaurants, Cocktail Lounges 1,700
Service Stations 1,000
Shopping 1,500
Srvc Shps:Radio, TV, Refrig, Pnt Shp 1,000
Stores 1,500
Supermarkets 1,500
Government 800
Industrial
Food Processing Plants 1,500
Lgt Manf.Sm. EQPT. Manuf Sm.Shps Instr.Manuf. Prnt Plnts 1,500 Lumber Yards 800
Warehousing, Distribution, Storage 500
Institutional
Cemeteries, Mausoleums, Mortuaries 800
Churches 800
Homes For Aged & Others 1,500
Hospitals 1,500
Schools (Private) 800
Petroleum & Gas 500
Utility Commercial & Mutual: Pumping Plants State
Assessed Pr 500
Recreational
Athletic & Amusement Facilities 1,500
Clubs., Lodge Halls, Fraternal Organizations 1,500
Theaters 1,500
A year of water use data from September 2022 through September 2023 for the top 15 water users was provided by the City and reviewed to determine if high use parcels should be converted into specified point loads, rather than utilizing sewer loading factors. Differences between the water meter flows and the model were small and inconsistent. All water consumption was within expected ranges and no exceptions were made in sewer loading for these users. The total sewer flow within the City by land use type is included in Table 6-3 using the flow factors presented in Table 6-2.

Land Use Description Area (ac)
Dwelling
Units Flow Factor
Average Flow
(gpd)
Commercial 138 gpd/ac 188,975
Auto, Recreation EQPT, Construction EQPT, Sales & Service 9.0 1,000 9,045 Banks Savings & Loan 1.0 1,500 1,512
Commercial 7.1 1,500 10,654
Hotel & Motels 3.7 1,500 5,552
Office Buildings 12.9 1,500 19,399
Professional Buildings 3.0 1,500 4,549
Restaurants, Cocktail Lounges 7.1 1,700 12,047
Service Stations 3.7 1,000 3,711
Shopping Centers 34.7 1,500 51,986
Srvc Shps:Radio, TV, Refrig, Pnt Shp 0.6 1,000 642
Store Combination 16.2 1,500 24,274
Stores 28.2 1,500 42,309
Supermarkets 1.6 1,500 2,403
Government 1.1 800 894
Government 42 63,430
Government Parcel 42.3 1,500 63,430
Industrial 5 4,765
Food Processing Plants 0.3 1,500 472
Lgt Manf.Sm. EQPT. Manuf Sm.Shps Instr.Manuf. Prnt Plnts 2.0 1,500 2,978 Lumber Yards 0.3 800 234
Open Storage 0.2 500 82
Warehousing, Distribution, Storage 2.0 500 999
Institutional 28 23,557
Cemeteries, Mausoleums, Mortuaries 0.4 800 343
Churches 14.2 800 11,351
Homes For Aged & Others 1.3 1,500 1,889
Hospitals 0.8 1,500 1,166
Schools (Private) 11.0 800 8,808
Miscellaneous 3.4 448
Petroleum & Gas 0.9 500 448
Utility Commercial & Mutual: Pumping Plants State Assessed Pr 2.5 500 1,258 Recreational 151,695 5,224
Athletic & Amusement Facilities 1.5 1,500 2,276
Clubs., Lodge Halls, Fraternal Organizations 1.7 1,500 2,571 Theaters 0.3 1,500 377
Residential 2,097 8,751 gpd/du 1,282,690
Five or more apartments 346.1 2,814 100 281,400
Four Units (Any Combination) 25.6 346 100 34,600
Mobile Home Parks 24.8 605 100 60,500
Multi-Family 1,118.6 598 160 95,680
Senior Home 48 100 4,800
Single 366.3 3,035 210 637,350
Three Units (Any Combination) 37.4 478 110 52,580
Two Units 75.6 827 140 115,780
Grand Total 2,317 9,413 1,569,088
TABLE 6-3
TABLE 4 - SEWER FLOW BY LAND USE TYPE

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The total estimated average flow of 1.61 mgd results in an average residential flow per dwelling unit of 147 gallons per day per dwelling unit (gpd/du). Census data for the City of Lomita estimates and average of 2.64 people per dwelling unit. The State of California Department of Water Resources has adopted an indoor water use target of 55 gallons per person per day, with the same amount resulting in sewer flow. Using this data, the average household sewer flow would equal 145 gpd/du, very similar to the calibrated sewer flow.

The land use and flow factors were used to calculate the sewer flow for each parcel which was stored in a polygon shape file. ArcMap tools were used to create a point feature for each parcel polygon. The parcel data point was then used in the Load Allocation Manager, to apply the sewer load to the closest model manhole. Further manual verification was conducted and adjustments were made to ensure that each parcel data point was allocated to the proper manhole in each basin.

6.2.2 Peaking Analysis/Relationship
PDWF was determined using the flow monitoring data. A diurnal peaking curve for this project was developed based on an analysis of the hourly flow compared to the ADWF monitored during the flow monitoring program. Due to the small amount of non-residential flow contribution to the flow monitoring sites, a typical diurnal curve for non-residential flow was assumed. The residential curve was then calibrated to the flow monitoring data. The resulting modeled maximum peaking factors (peak flow over average flow) for the basins range between 1.72 and 1.74. The results of the peak flow calibration at each basin yielded relatively higher flows than the flow monitoring results, which are conservative but still relatively true to real world conditions. Model hourly peaking factors for residential and non-residential uses are included in Appendix D.

6.2.3 Calibration Results
The diurnal peaking curve was applied to the ADWF loads in the model. The results of the PDWF scenario yielded flows similar to those observed in the City’s system under peak dry weather conditions. The results of the average and peak dry weather flow calibration at each flow basin as delineated in the flow monitoring program are summarized in Table 6-4. Appendix D includes hydrographs comparing measured flow during the monitoring period to simulated flow for an extended period simulation.

Table 6-4
Dry Weather Flow Calibration Summary
Site
Average (gpm) Peak Weekday (gpm) Max Peak Factor
FM Model %Diff FM Model %Diff FM Model
1 148.7 174.3 17% 265.2 299.9 13% 1.78 1.72
2 202.9 209.2 3% 339.4 362.1 7% 1.67 1.73
3 69.4 76.0 9% 121.1 132.4 9% 1.74 1.74
Table 6-4 shows good correlation between the modeled and monitored PDWF. Site #1 has the largest difference between observed and monitored flows. It should be noted that Basin 1, flowing into Site #1, contains the largest number of apartment units. There are 503 apartment units within that basin, equal to 31% of the total dwelling units. The flow factor was applied to each unit;

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however, it is likely the apartments are not 100% occupied, causing modeled flow to be higher than observed. It is also important to recognize that the actual difference in monitored versus modeled flow is relatively small compared to the capacity of the pipelines. The difference in flow represents only approximately 3% of the pipeline capacity.

Based on the flow monitoring data, the flow factors in Table 6-2 are recommended for land usebased flow generation within the sewer model for the capacity analysis of the sewer collection system. The recommended factors result in modeled peak flow ranging between 7 and 13% higher than actual monitored flow, which is an appropriate level of conservatism for this study.

6.3 Existing and Projected Flows

6.3.1 Average Dry Weather Flow
Existing Sewer Flow
The ADWF input into the existing scenario model was calculated based on existing land use GIS data by parcel provided by the City. The land use flow factors developed from the flow monitoring and model calibration, presented in Table 6-2, were used to calculate the sewer flow for each parcel, and that flow was loaded to the closest model manhole as discussed in Section 6.2, Dry Weather Calibration.

Buildout Sewer Flow Projections
The data provided from the City’s Preferred Land Use Plan and corresponding GIS shapefile were used to develop buildout flow projections and model loading. Two buildout scenarios were developed based on the City planning data.

Buildout Scenario 1
The first buildout scenario, Scenario 1, is based on the projected number of dwelling units and non-residential square footage presented in the Preferred Land Use Plan, MU 70 alternative. The new mixed-use designations generate a buildout projection of 4,298 dwelling units (Section 5.2, Table 5-3) and 3.23 million square-feet of non-residential use (Section 5.2, Table 5-4). These growth projections were applied to the various mixed-use designations to develop sewer generation factors per acre for each proposed land use.

The residential loading component for mixed-use units is assumed to equal the loading factor of 100 gallons per day per dwelling unit (gpd/du) that is used for Apartments (5 or more units) in the Existing Condition scenario. Existing non-residential uses were assigned loading factors per acre due to the lack of more detailed information on square footage. The existing land use acreage was evaluated to determine the approximate percentage breakdown or mix of three typical nonresidential uses within the City - Restaurant, Retail, and Office use types. These same percentages were applied to estimate the percent of various non-residential uses for future growth as shown in Table 6-5. Also included in Table 6-5 are typical flow factors per thousand square feet (ksf) for the non-residential uses. A weighted average of these factors, based on typical percentages of various non-residential uses, was used to develop a single (weighted average) flow factor of 195 gpd/ksf for projected non-residential use (rounded up from 194).

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
6-10 October 2024
Table 6-5
Non-Residential Use Flow Factor
NonResidential
Land Use
Percent by
Land Use
Flow Factor
(gpd/ksf)
Restaurant 10% 800
Retail 60% 150
Office 30% 80
Weighted Factor 194
The projected non-residential square footage equals 3.23 million and the total mixed-use designated area equals 10.45 million square feet, for an average Floor Area Ratio (FAR) of 0.31.

This FAR was used to apply the non-residential square footage to the various mixed-use designations by land use area. Table 6-6 shows the resulting flow factors in gallons per day per acre for each of the new mixed-use designations using the Preferred Land Use Plan projected dwelling units and non-residential square footage.

Table 6-6
Buildout Scenario 1 Loading Factors – Maximum Mixed-Use Land
Use
LU
Plan
Acres
LU Plan
DUs
Calc’d
DU/acre1
Non-Res
SF
(0.31 FAR)
Res Flow
(gpd)2
Non-Res
Flow
(gpd)3
Total
Flow
(gpd)
Flow
Factor
(gpd/ac)4
M-C70 7 180 26 94,151 18,000 18,360 36,360 5,194
M-C40 8 105 13 107,602 10,500 20,982 31,482 3,935
MU30 13 141 11 174,853 14,100 34,096 48,196 3,707
MU40 144 2,026 14 1,936,829 202,600 377,682 580,282 4,030 MU70 68 1,846 27 914,614 184,600 178,350 362,950 5,337
TOTAL 240 4,298 3,228,048 429,800 629,469 1,059,269 4,414 (1) Land Use Plan DUs from Table 5-3 divided by Land Use Plan acres from Table 5-2. (2) Residential gallons per day equals the number of dwelling units multiplied by 100 gpd/du. (3) Non-residential gpd equals the square footage times a factor of 195 gpd/ksf. (4) Flow factor is calculated by dividing the total gpd by the land use acres.

Existing land uses were loaded using the same factors as the Existing Condition scenario, with the exception of single-family residential use. The single-family use factor was increased by 5 percent (from 210 gpd/du to 220.5 gpd/du) to account for future ADUs and the 2 percent projected population growth for single-family use provided in the Preferred Land Use Plan and presented in Section 5.2, Table 5-4.

Buildout Scenario 2
The second buildout scenario, Scenario 2, assumes that the maximum residential density is built out for each of the mixed-use designations. This is a worst-case scenario as residential loading results in higher sewer flows than the combined residential and non-residential uses presented in Scenario 1. As shown in Table 6-6 for Scenario 1, the calculated dwelling units per acre is

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
6-11 October 2024
significantly less than the maximum allowed. Table 6-7 shows the number of dwelling units and corresponding residential loading factor (i.e., flow factor) using the maximum allowed densities for each land use designation. As shown, the total number of dwelling units equals 11,720 versus the 4,298 dwelling units projected in the Preferred Land Use Plan. For Scenario 2, non-residential use is excluded as the entire acreage is applied to residential uses. The resulting sewer generation and average flow factor is 11 percent higher than Scenario 1.

Table 6-7
Buildout Scenario 2 Sewer Loading – Maximum DUs
Land Use
LU Plan
Acres
Max # of
DU/AC
Max # of
DUs
Max DU
Flow (gpd)
Flow Factor
(gpd/ac)
M-C70 7 70 490 49,000 7,000
M-C40 8 40 320 32,000 4,000
MU30 13 30 390 39,000 3,000
MU40 144 40 5,760 576,000 4,000
MU70 68 70 4,760 476,000 7,000
TOTAL 240 11,720 1,172,000 4,883
As with Scenario 1, existing land uses were loaded using the same factors as the Existing Condition scenario, with the exception of single-family residential use. Similar to Scenario 1, the singlefamily use factor was increased by 5 percent (from 210 gpd/du to 220.5 gpd/du) to account for future ADUs and the 2 percent projected population growth for single-family use provided in the Preferred Land Use Plan presented in Section 5.2, Table 5-4.

The two buildout scenarios were developed in the model using the Proposed General Plan Land Use parcel data provided in GIS. Parcels that would change land use as part of the Preferred Land Use Plan were loaded using the factors developed above. Parcels with no proposed land use changes were loaded using the existing land use data with single-family use increased by 5 percent.

Each parcel was loaded by land use type to the nearest upstream model manhole using the designated loading factor. The projected buildout sewer flow by Proposed General Plan Land Use designation for Scenarios 1 and 2 are shown in Table 6-8.

6.3.2 Peak Dry Weather Flow
Peak dry weather flow is the highest measured flow that occurs on a dry weather day. The PDWF was developed by applying a peaking factor based on the peaking curve developed from the flow monitoring program as discussed in Section 6.2. The peaking curve was applied to the average dry weather flows loaded into the model for Existing and Buildout Scenarios.

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
6-12 October 2024
Table 6-8
Buildout Sewer Flow Projections
Proposed General Plan
Land Use
Buildout Scenarios (gpd)
Scenario 1 Scenario 2
MCMU(1) 42,663 43,357
Mixed-Use 30 49,159 39,773
Mixed-Use 40 544,636 540,582
Mixed-Use 70 380,398 498,836
Public Owned Land 93,699 93,699
Parcels Outside City(2) 55,157 55,157
Residential Uses
Agricultural 96,723 96,723
Low Density 757,384 757,384
Medium Density 119,602 119,602
High Density 67,119 67,119
Grand Total 2,206,540 2,312,231
(1) Manufacturing-Commercial Mixed-Use
(2) Parcels located outside of the City that are tributary to the City's sewer system.

6.3.3 Design Wet Weather Flow
Design wet weather flow is the highest measured hourly flow that occurs during a design wet weather rain event. It consists of the ADWF plus any rainfall-dependent infiltration/inflow and base groundwater infiltration flow. The CSMD Sewer System Management Plan did not indicate the presence of significant infiltration/inflow. Therefore, this Master Plan will use the PDWF to identify pipes that need capacity enhancement. As discussed in the next chapter (Sections 7.4 and

7.5), the d/D ratio utilized will allow for sufficient capacity for wet weather flow.

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN

7-1 October 2024

7.0 SEWER DESIGN CRITERIA
Sewer pipe capacities are dependent upon many factors. These include the roughness of the pipe, the maximum allowable depth of flow, and limiting velocity and slope. The Continuity Equation and the Manning’s Equation for steady state flow are used for gravity sewer hydraulic calculations:

Continuity Equation: Q = V A
Manning’s Equation: Q = (1.486 AR2/3 S1/2)/n
where:

Q = peak flow, cfs
V = velocity, fps
A = cross-sectional area of flow, sq. ft. (when d/D = 1.0) n = Manning’s coefficient of friction
R = hydraulic radius (area divided by wetted perimeter), ft S = slope of energy gradient (approximated by slope of pipe), ft/ft

7.1 Manning’s Coefficient (n)
The Manning’s coefficient ‘n’ is a friction coefficient and varies depending on the type of material.

For example, glass would have an ‘n’ value of 0.010 while earth channels would have an ‘n’ value of 0.020. There has been much debate about the appropriate ‘n’ value to use for different piping materials in sanitary sewer systems. To complicate the debate, the slime layer that thrives on the wetted portions of the sanitary piping also contributes to and affects the actual value of ‘n’. This study will utilize an ‘n’ value of 0.015 based on a conservative value for VCP, which makes up the majority of the City’s wastewater collection system.

7.2 Design Velocities
All sewers shall be designed and constructed to give mean velocities, when flowing half full (d/D ratio is 0.50). To maintain the suspension of solids in sewers, the minimum design velocity shall be 2 ft/sec during the PDWF at the time the pipe is placed into service. The maximum design velocity shall be limited to 10 ft/sec at the peak flow rate. Using Manning’s Equation above, one can calculate the minimum slope necessary to achieve the minimum design velocity of 2 ft/sec for a given diameter of pipe. Performing this calculation for pipes 8- to 18-inch in diameter results in the minimum slopes provided in Table 7-1, which should be used for designing new or replacement improvements. Of course, certain existing conditions may require exceptions to these minimum slopes, which should be evaluated on a case-by-case basis.

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
7-2 October 2024
Table 7-1
Minimum Slopes by Pipe Size
Pipe Size (in) Minimum Slope
(ft/ft)
8 0.0040
10 0.0028
12 0.0022
15 0.0016
18 0.0012

7.3 Existing Pipe Flow Depth Criteria (d/D)
The capacity criteria for gravity sewers are typically evaluated by a ratio of flow depth over pipe diameter (d/D). Sewers for this analysis shall be evaluated so the d/D ratios (specified below) are not exceeded while flowing under the PDWF conditions. Utilizing these d/D ratios for PDWF provides an adequate allowance for peak wet weather flow in the top portion of the pipe. 15-inch and larger d/D greater than 0.75
12-inch and smaller d/D greater than 0.67

7.4 Recommended Pipe Improvements Criteria
Recommended improvements for pipeline segments identified for capacity enhancement are based on the following slightly more conservative sizing criteria (than allowed for existing pipes) to provide capacity for unforeseen conditions:
• Replacement diameter shall be sized using the following d/D criteria:
o 15-inch and larger – d/D less than or equal to 0.60
o 12-inch and smaller – d/D less than or equal to 0.50
• Pipe replacement is recommended for existing small diameter (6-, 8-, 10- and 12-inch) pipes rather than recommending a parallel system, as there are only minimal cost savings in using these smaller lines along with an additional parallel line. Also, street sections are more cluttered with two sets of pipes and manholes. • Either pipe replacement or a parallel system is recommended for existing 15-inch diameter pipes, on a case-by-case basis. This decision would typically be dependent on the pipeline’s useful life remaining and available room within the street section. • Generally, only a parallel system is recommended for existing 18-inch diameter pipes and larger.
• For pipe diameters 8-inch and 10-inch, no downstream downsizing is allowed.

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
7-3 October 2024

7.5 Sewer Flow Factors
When planning for future development projects, it is recommended to conduct a sewer study to evaluate the available capacity in the City’s downstream sewer system to collect and discharge existing plus project flows and to assess any project related impacts. Unit flow factors were developed during model calibration based on existing land use data and the results of the temporary flow monitoring study as discussed in Section 6.2. The residential flow factors were developed in gallons per day per dwelling unit (gpd/du) for the various residential densities. Non-residential flow was generated using typical planning factors in gallons per day per acre (gpd/ac). The recommended residential and non-residential factors are provided in Table 6-2.

When new development projects are proposed, there is typically detailed information on the various uses that include building area and expected occupancy rates. As such, recommended loading factors may be based on more detailed planning data as available. Residential uses continue to be loaded using a unit factor per dwelling unit unless projected occupancy is available, in which case, it is recommended that average sewer flow be calculated on a per person basis. The recommended unit flow factors for average dry weather flow (ADWF) are shown in Table 7-2.

Table 7-2
Sewer Planning Unit Flow Factors
Land Use
ADWF Unit
Flow Factor Units
Residential Use
Single-Family 210 gpd/du
Multi-Family 160 gpd/du
Two Units 140 gpd/du
Three Units 110 gpd/du
Apartment/Mobile Homes 100 gpd/du
Per person(1) 55 gpcd
Non-Residential Use
Restaurant 800 gpd/ksf
Commercial/Retail 150 gpd/ksf
Office 80 gpd/ksf
(1) Detailed information on occupancy may use 55 gallons per capita per day (gpcd)
For sewer peaking, it is recommended to use the model peaking curves developed during calibration and presented in Section 6.2. The resulting peak dry weather flow (PDWF) is equal to

1.8 times the ADWF.

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
8-1 October 2024

8.0 COLLECTION SYSTEM ANALYSIS
Existing and Buildout Scenario wastewater collection system areas identified for capacity enhancement and potential corrections can be determined by running and analyzing the different sewer model scenarios. These scenarios analyze the existing wastewater collection system under the existing flows as calibrated from the flow monitoring data and projected buildout flows based on the City’s Preferred Land Use Plan.

8.1 Existing Scenario
The City’s existing wastewater collection system was evaluated in the Existing Scenario. The Existing Scenario analysis of the wastewater collection system uses the existing flows that were calibrated to the flow monitoring data. Using the analysis criteria presented above, there are existing pipelines nearing the maximum capacity limit but none are identified as deficient.

Modeled d/D ratios are illustrated on Figure 8-1 with model pipeline output presented in Appendix E. The output table in Appendix E includes pipeline upstream and downstream manhole numbers (to identify the pipe reach), pipe length, pipe diameter, and the following model output data:
• Existing Flow and d/D Ratio - the existing peak flow and resulting d/D, • Analysis Flow - flow capacity limit of the pipeline using the maximum allowed d/D, • Analysis Excess - the remaining available capacity of the pipeline based on the Analysis d/D criteria,
• Design Flow - flow capacity of the pipeline using the more conservative Design d/D, • Design Excess - the remaining capacity in the pipeline based on the Design d/D criteria, • SFR DUs - calculated number of additional single-family units that can be served by the existing pipeline without exceeding the Analysis d/D criteria, and • Apartment Units - calculated number of additional apartment units that can be served by the existing pipeline without exceeding the Analysis d/D criteria. The number of apartment units is not in addition to the number or single-family units (either single-family units or apartment units)
The pipelines nearing capacity in the Existing Scenario are indicated as green on Figure 8-1 and have d/D ratios between 0.50 and 0.67. These pipeline segments indicate d/D ratios below the replacement criteria but exceeding the capacity design criteria for 12-inch or smaller lines. The green segments are flagged and identified as Watch List facilities to monitor for capacity enhancements if additional flow is introduced upstream from development, re-development, or construction of ADUs. If a line is 15-inch or larger it would be Watch Listed beyond 0.67 up to

0.75 d/D. The rationale here is that a sewer segment with a PDWF d/D of 0.55, for example, may not be a desirable condition for designing a new replacement line but, for an existing pipeline, as long as no new development is proposed upstream and the pipeline segment is in good condition, there is no need to replace/upsize it at this time.

1652-0211
1651-0293
1652-0190
1652-0221
1652-0185
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1652-0220
1652-0194
1652-0204
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1652-0318
1652-0224
1651-0322
1651-0292
1651-0071
1651-0073
1652-0217
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1652-0184
1652-0174
1652-0192
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1652-0223
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1652-0317
1652-0316
1652-0324
1652-0208
1652-0629
1652-0406
1652-0329
1652-0558
1652-0328
1652-0394
1652-0631 1652-0634
1652-0383
1651-0016 1651-0021
1652-0557
1652-0544
1652-0552
1652-0469 1652-0565
1652-0411
1652-0484
1652-0472
1652-0583
1652-0575
1652-0620
1652-0400
1652-0386
1652-0475
1652-0335
1652-0393
1652-0612
1652-0466
1652-0330
1652-0407
1652-0582
1652-0616
1652-0593
1652-0483
1652-0567
1652-0409
1652-0485
1652-0482
1652-0490
1652-0481
1652-0467
1652-0556 1652-0399
1652-0553
1652-0388
1652-0468
1652-0584
Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
Pipeline d/D
< 0.50

0.50 - 067

0.67 - 0.75
> 0.75
Figure 8-1 - Existing Scenario
Peak Flow d/D

PENNSYLVANIA AVE CYPRESS ST OAK ST ESHELMAN AVE BACK YARD PIPELINE

EBONY LN
250TH ST 248TH ST

PACIFIC COAST HWY

0.67 CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
8-3 October 2024
The Watch List segments are summarized in Table 8-1. Several of the segments are approaching capacity due to flat slopes while adjacent pipelines, with steeper slopes, have excess capacity. The segments listed in Table 8-1 are flagged with d/D ratios between 0.50 and 0.67 and are identified to be monitored for future capacity issues.

Table 8-1
Existing Capacity Watch List Segments
Street Name From MH To MH
Diam.
(in)
Length
(ft) Slope
Existing
Flow
(gpm)
d/D
Ratio
Remaining
Capacity
(gpm)
SFR
DUs
Limit(1)
Apt.

Units
Limit(2)
Pennsylvania
Ave
1652-0544 1652-0546 8 68.8 0.0010 90.7 0.50 51.21 195 410 1652-0567 1652-0575 10 87.5 0.0010 144.2 0.50 83.83 319 671 Oak St 1652-0386 1652-0388 8 135.8 0.0010 78.0 0.56 22.98 88 184 Back Yard
Pipeline
(PCH to
Lomita)
1652-0174 1652-0184 10 336.8 0.0060 313.5 0.50 190.43 725 1,523 1652-0189 1652-0190 10 182.5 0.0060 337.6 0.51 183.68 700 1,469 1652-0190 1652-0192 10 176.2 0.0060 337.6 0.50 195.36 744 1,563 1652-0192 1652-0193 10 142.9 0.0070 344.4 0.50 199.79 761 1,598 1652-0194 1652-0201 10 177.3 0.0060 344.4 0.52 162.21 618 1,298 1652-0212 1652-0217 10 305.6 0.0060 373.5 0.54 142.72 544 1,142 (1) Remaining number of single-family residential units that could discharge to pipeline without reaching capacity limit. (2) Remaining number of apartment units that could discharge to pipeline without reaching capacity limit. The number of SFR (Note 1) and apartment units that can discharge cannot be combined, it is either/or.

8.2 Buildout Scenarios
The City’s existing wastewater collection system was evaluated for the Buildout Scenarios described in Section 8.2. Using the d/D analysis criteria, the results revealed capacity deficient pipelines in the existing collection system under buildout flows.

The capacity analysis for Buildout Scenario 1 is presented on Figure 8-2 with model output included in Appendix E. Buildout Scenario 1 incorporates the buildout residential units and nonresidential square footage projected in the City’s Preferred Land Use Plan. In this scenario, there are seven capacity deficient reaches resulting from buildout flow projections. There are six deficient reaches of 10-inch pipeline aligned outside of roadways and through developed properties between PCH and Ebony (labeled as back yard pipeline). The remaining reaches along the back yard pipeline are approaching the analysis capacity with modeled d/D ratios at or above

0.50. There is one deficient 8-inch reach along Oak Street. This reach has a flat slope and with model results indicating that the pipeline flows full under this Buildout Scenario. 1652-0211
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1651-0322
1651-0292
1651-0071
1651-0073
1652-0217
1652-0189
1652-0184
1652-0174
1652-0192
1652-0222
1652-0223
1652-0315
1652-0317
1652-0316
1652-0324
1652-0208
1652-0629
1652-0406
1652-0329
1652-0558
1652-0328
1652-0394
1652-0631 1652-0634
1652-0383
1651-0016 1651-0021
1652-0557
1652-0544
1652-0552
1652-0469 1652-0565
1652-0411
1652-0484
1652-0472
1652-0583
1652-0575
1652-0620
1652-0400
1652-0386
1652-0475
1652-0335
1652-0393
1652-0612
1652-0466
1652-0330
1652-0407
1652-0582
1652-0616
1652-0593
1652-0483
1652-0567
1652-0409
1652-0485
1652-0482
1652-0490
1652-0481
1652-0467
1652-0556 1652-0399
1652-0553
1652-0388
1652-0468
1652-0584
Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
Pipeline d/D
< 0.50

0.50 - 067

0.67 - 0.75
> 0.75
Figure 8-2 - Buildout Scenario 1
Preferred Land Use Plan Projected Densities
Peak Flow d/D

PENNSYLVANIA AVE CYPRESS ST OAK ST ESHELMAN AVE BACK YARD PIPELINE

EBONY LN
250TH ST 248TH ST

PACIFIC COAST HWY WALNUT STREET

0.67 CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
8-5 October 2024
The capacity analysis for Buildout Scenario 2 is presented on Figure 8-3 with model output included in Appendix E. Buildout Scenario 2 is described in Section 6.3 and incorporates the maximum number of buildout residential units based on the maximum allowed residential densities presented in the City’s Preferred Land Use Plan. This represents the worst-case buildout scenario. In Buildout Scenario 2, there are eight capacity deficient reaches resulting from buildout flow projections. As with Scenario 1, there is one deficient 8-inch reach along Oak Street that models as flowing full. The remaining deficient reaches are along the 10-inch back yard pipeline between PCH and Ebony and include four reaches exceeding a d/D ratio of 0.75.

The maximum d/D ratio along the 10-inch pipeline is 0.81 with none of the pipelines modeled as flowing full. The remaining reaches along the back yard pipeline are approaching pipeline capacity with all modeled d/D ratios at or above 0.54. As such, the entire pipeline is considered deficient under buildout flows.

Table 8-2 shows the pipelines that have reached capacity or are approaching capacity under Buildout Scenario 2 representing the worst-case scenario. Based on the model results, the 10-inch pipeline running through developed properties between PCH and Ebony should be replaced as part of a Capital Improvement Program. The pipeline was constructed in the 1930s with existing flow nearing the available capacity and buildout flows exceeding pipeline capacity. The modeled d/D ratios vary with some segments below the replacement criteria; however, any improvements will involve replacing the entire pipeline.

There are individual reaches elsewhere in the system that are nearing capacity due to flat slopes.

Improvements in these situations may involve upsizing the single reach and potentially upsizing downstream reaches to avoid sewer flow to a more restrictive pipeline. There may also be potential to increase the slope of the flat segment by replacing adjacent reaches with different (flatter) slopes, thus providing a more consistent slope across all reaches. 1652-0211
1651-0293
1652-0190
1652-0221
1652-0185
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1652-0194
1652-0204
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1652-0318
1652-0224
1651-0322
1651-0292
1651-0071
1651-0073
1652-0217
1652-0189
1652-0184
1652-0174
1652-0192
1652-0222
1652-0223
1652-0315
1652-0317
1652-0316
1652-0324
1652-0208
1652-0629
1652-0406
1652-0329
1652-0558
1652-0328
1652-0394
1652-0631 1652-0634
1652-0383
1651-0016 1651-0021
1652-0557
1652-0544
1652-0552
1652-0469 1652-0565
1652-0411
1652-0484
1652-0472
1652-0583
1652-0575
1652-0620
1652-0400
1652-0386
1652-0475
1652-0335
1652-0393
1652-0612
1652-0466
1652-0330
1652-0407
1652-0582
1652-0616
1652-0593
1652-0483
1652-0567
1652-0409
1652-0485
1652-0482
1652-0490
1652-0481
1652-0467
1652-0556 1652-0399
1652-0553
1652-0388
1652-0468
1652-0584
Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
Pipeline d/D
< 0.50

0.50 - 067

0.67 - 0.75
> 0.75
Figure 8-3 - Buildout Scenario 2
Maximum Residential Density
Peak Flow d/D
1652-0212 PENNSYLVANIA AVE CYPRESS ST OAK ST ESHELMAN AVE

EBONY LN
250TH ST 248TH ST

PACIFIC COAST HWY BACK YARD PIPELINE

0.67 CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
8-7 October 2024
Table 8-2
Buildout Scenario 2 Limiting Capacity Pipelines
Street Name From MH To MH
Diam.
(in)
Length
(ft) Slope
Existing
Flow
(gpm)
d/D
Ratio
Analysis
Excess
(gpm)
Pennsylvania
Ave
1652-0544 1652-0546 8 68.8 0.0010 100.3 0.53 41.6
1652-0567 1652-0575 10 87.5 0.0010 158.5 0.53 69.5
Cypress St 1652-0476 1652-0475 8 47.5 0.0020 112.9 0.51 57.8 1652-0612 1652-0466 10 100.2 0.0010 145.5 0.52 67.6
Oak St 1652-0386 1652-0388 8 135.8 0.0010 157.2 1.00 -56.2 Eshelman
Ave 1652-0323 1652-0318 8 55.3 0.0020 100.6 0.50 57.6
Back Yard
Pipeline
1652-0174 1652-0184 10 336.8 0.0060 590.6 0.76 -86.7
1652-0184 1652-0185 10 189.1 0.0120 603.3 0.58 142.3
1652-0185 1652-0189 10 179.1 0.0130 603.3 0.56 177.5
1652-0189 1652-0190 10 182.5 0.0060 613.6 0.76 -92.2
1652-0190 1652-0192 10 176.2 0.0060 613.5 0.75 -80.5
1652-0192 1652-0193 10 142.9 0.0070 620.3 0.74 -76.1
1652-0193 1652-0194 10 36.2 0.0120 620.3 0.60 114.3
1652-0194 1652-0201 10 177.3 0.0060 620.3 0.79 -113.7
1652-0201 1652-0202 10 240.6 0.0160 629.9 0.55 228.8
1652-0202 1652-0204 10 65.2 0.0170 629.8 0.54 250.6
1652-0204 1652-0617 10 70.8 0.0170 631.9 0.54 246.0
1652-0617 1652-0616 10 40.9 0.0170 631.9 0.54 250.0
1652-0616 1652-0208 10 182.0 0.0170 633.7 0.54 245.1
1652-0208 1652-0211 10 264.8 0.0120 642.7 0.62 83.5
1652-0211 1652-0212 10 198.2 0.0090 648.8 0.69 -24.1
1652-0212 1652-0217 10 305.6 0.0060 650.1 0.81 -133.9
Ebony Ln 1652-0217 SD1707 12 315.7 0.0050 713.0 0.62 216.9 Highlighted pipelines are also capacity deficient in Buildout Scenario 1. The remaining pipelines are approaching capacity.

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
9-1 October 2024

9.0 CAPITAL IMPROVEMENT PLAN

9.1 Recommended Capital Improvement Plan Methodology
The capital improvements established in this Sanitary Sewer System Master Plan are provided to the City as recommended solutions to the buildout sewer capacity constraints and provide additional capacity for buildout development within the study area. The pipeline segments which were determined as capacity deficient are addressed in the Capital Improvement Program based on the modeled d/D ratios.

9.2 Existing Collection System Limiting Capacity Areas
Based on the results of the Existing Scenario, nine pipeline segments were identified for the Watch List, as presented in Table 9-1. The areas identified with limited remaining capacity should be monitored closely, and if further problems arise, a sewer improvement would be recommended.

The Watch List is provided so that the City can monitor the areas identified for increases in flow and other issues reported by the CSMD such as odor issues, blockages, and surcharges which may indicate a sewer improvement may be required. Pipelines which exceed d/D ratios of 0.67 (all 12- inch or smaller) are recommended for improvement with either an upstream, flow diversion, or replacement pipelines.

Table 9-1
Watch List – Existing Limiting Capacity Areas
Street Name From MH To MH
Diam.
(in)
Length
(ft)
Pennsylvania Ave 1652-0544 1652-0546 8 69
1652-0567 1652-0575 10 88
Oak St 1652-0386 1652-0388 8 136
Back Yard Pipeline
1652-0174 1652-0184 10 337
1652-0189 1652-0190 10 182
1652-0190 1652-0192 10 176
1652-0192 1652-0193 10 143
1652-0194 1652-0201 10 177
1652-0212 1652-0217 10 306
248th Street(1) 1651-0016 1651-0017 8 319
(1) Recommended for replacement under existing conditions.

Based on review of the CSMD 2019 Condition Assessment Program Report for the City of Lomita, high water marks are identified along a pipeline reach in 248th Street due to a sag in the pipeline.

Though this pipeline is not modeled as capacity deficient, it is recommended for replacement based on this condition assessment. It should be noted that the CSMD Condition Assessment Program Report stated “No maintenance action needed” for the observed sag. As such, CCTV video review is recommended prior to improvements. The CSMD report also identified this pipeline with an observed hole and proposed point repair as the corrective action.

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
9-2 October 2024
The CSMD completed the latest CCTV inspection between April and December 2021, however, the Condition Assessment Program Report has not been completed. The CSMD expects the completed report will be available later this year, at which point, additional improvement areas may be identified. This report should be reviewed by the City when available.

9.3 Wastewater Collection System Improvements
Wastewater collection system improvements are recommended for implementation (design and construction) to correct areas identified with capacity constraints under buildout conditions. Based on review of the CSMD 2019 Condition Assessment Program Report, high water marks were identified along a pipeline reach in 248th Street due to a sag in the pipeline. Though this pipeline is not identified as capacity deficient, it is recommended for replacement based on the condition assessment. The following Capital Improvement Projects are recommended to provide adequate capacity for buildout flows and correct structural damage:

1. PCH to Ebony Improvement

2. 248th Street Improvement

3. Oak Street Improvement

9.3.1 PCH to Ebony Capital Improvement
To address the capacity issue resulting from the back yard pipelines from PCH to Ebony, the 2,800 linear feet (LF) of existing 10-inch pipeline would need to be upsized in place to 12-inch diameter.

However, it is not recommended to replace this pipeline in the existing location due to the alignment through back yards. The pipeline was constructed in the 1930s, and the alignment through back yards creates maintenance and access issues.

The closest City sewer aligned within a roadway is along Walnut and Ebony as illustrated on Figure 9-1. Based on conceptual analysis, it is recommended to abandon the 10-inch pipeline running along the back yards between PCH and Ebony and direct tributary flow to a new 15-inch replacement pipeline along Walnut and Ebony. This CIP will also include the construction of new 8-inch pipelines along side streets to direct sewer flow from areas served by the abandoned pipeline toward the new pipeline. The recommended CIP replaces 2,800 LF of 10-inch pipeline (to be abandoned) with approximately 9,800 LF of 15- and 8-inch pipeline as summarized in Table 9-2.

Table 9-2
CIP #1 Improvement Quantities
Location
Diam.
(in)
Length
(LF)
No. of
MH
Walnut and Ebony 15 3,350 16
All Cross Streets 8 6,425 32
Total 9,775 48
Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community

BACK YARD PIPE (TO ABANDON)
New 15-inch
Pipeline
New 8-inch Cross
Street Pipes CIP #1 FLAT SLOPE 1652-0393 1652-0388 1652-0386 1652-0383 CIP #2 CIP #3 248th StOak Street Pacific Coast Highway Ebony Ln
Walnut St
New 8-inch
Pipe
New 8-inch
Pipes
1651-0016 1651-0017 SAG
Figure 9-1
Proposed CIP Areas

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
9-4 October 2024
Prior to moving forward with this project, a preliminary design level analysis to evaluate feasibility should be conducted. The replacement pipeline along Walnut and Ebony will need to be constructed deep enough to allow gravity flow from the areas previously served by the back yard pipeline. The resulting flow direction is against the natural topographic gradient. An initial assessment was conducted to evaluate the feasibility.

The invert elevation of the San District pipeline at the discharge point from Ebony (equal to 38.9 feet) was obtained from available online data. Using the downstream invert elevation, the estimated length of improvement pipeline, and minimum slope criteria, it was calculated that the replacement pipeline may be constructed deep enough to collect flow from the back yard pipeline tributary area. In other words, the replacement pipeline would be lower in elevation than the existing back yard pipeline to allow gravity flow from the areas it served. These results must be confirmed through the survey of existing manholes, as part of a preliminary design report, to measure accurate invert elevations using a consistent datum and to check for potentially conflicting utilities.

The estimated improvement diameter of 15-inches was calculated using a minimum slope and peak flows from the larger tributary area. The pipeline size must be confirmed as part of a pre-design analysis using the proposed alignment and slopes.

It is recommended that the City move forward with the initial analysis of CIP #1 due to the age and location of the 10-inch back yard pipeline. Given the long-term planning effort for this improvement, there is the potential to divert flows away from the pipeline to the San District trunk sewer along Western Avenue as a near-term capacity solution. The diversion location (DIV #1) is along Western Avenue near 261st Street as illustrated on Figure 9-2. City pipelines are located near the 21-inch San District trunk sewer at this location, allowing for the potential connection to the San District manhole located on the east side of Western Avenue. This improvement would require approximately 250 LF of new 8-inch pipeline, and crossing Western Avenue, to connect to the San District manhole. This diversion improvement eliminates buildout capacity deficiencies along the back yard pipeline.

San District manholes located upstream (south) of DIV #1 provide alternative connection points; however, if the diversion moves upstream, less flow will be captured. Farther downstream and north of the DIV #1 location, the San District pipeline turns to the east and outside of the City boundary, discharging to a 24-inch trunk sewer along 260th Street. Previously, the San District pipeline continued north on Western Avenue, but that portion is now out of service.

The DIV #1 improvement captures a portion of the flow tributary to the back yard pipeline, including the 301-unit Harbor Hills Housing property. The area tributary to this diversion location is illustrated on Figure 9-2. The tributary area includes a residential neighborhood located to the west of Harbor Hills. Sewer flows from this neighborhood flow through the Harbor Hills private, on-site sewer prior to connecting to the City sewer pipeline along Western Avenue. City pipelines along Western Avenue and adjacent to the Harbor Hills Housing site also discharge through the private Harbor Hills sewers. The Harbor Hills on-site sewers carrying off-site City flows are illustrated on Figure 9-2. Psomas prepared a Technical Memorandum (included in Appendix F) to document the Harbor Hills pipelines that carry off-site City flows along with recommendations for the continued reliability and maintenance of these sewers.

Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
Legend
DIV #1
Back Yard Pipe Basin
County Pipeline
Out of Service County Pipe
261st Street Western Ave. BACK YARD PIPE
262nd Street
SMP DIV #1
Flow Diversion Alternate
Diversion Location
Harbor
Hills
Housing
Harbor Hills
On-Site Sewers
Carrying City
Sewage
Harbor
Hills
Housing LACSD Trunk Sewer
FIGURE 9-2
Flow Diversion Improvement
PCH Eshelman Ave.

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
9-6 October 2024

9.3.2 248th Street Capital Improvement
It is recommended to replace a reach of pipeline along 248th Street at Cypress Street between MH1651-0016 and MH1651-0017 to correct a sag. The pipeline sag was identified by the CSMD and results in observed high water marks and frequent cleaning. This structural damage cannot be mitigated by point repair or lining. The improvement pipeline is illustrated on Figure 9-1 with quantities provided in Table 9-3.

Table 9-3
CIP #2 Improvement Quantities
Location From MH To MH
Diam.
(in)
Length
(ft)
No. of
MH
248th Steet 1651-0016 1651-0017 8 319 2

9.3.3 Oak Street Capital Improvement
It is recommended to correct the flat slope along Oak Street between PCH and 256th Street (MH1652-0386 to MH1652-0388) by replacing the pipeline along with the adjacent segment(s) to provide sufficient slope. An evaluation of the existing system slopes and invert elevations along the pipelines from PCH to 256th Street shows sufficient slope available to correct the pipeline deficiency. A pre-design analysis will be required to confirm invert elevations and identify any construction concerns such as connecting pipelines and laterals and other utilities. Based on geometry alone, there is enough slope by replacing two pipeline reaches, the flat reach and the adjacent downstream reach (from MH1652-0386 to MH1652-0393). This CIP includes the upstream reach as well to provide for potential construction issues. The improvement pipelines are illustrated on Figure 9-1 with quantities provided in Table 9-4, with the one flat reach highlighted.

Table 9-4
CIP #3 Improvement Quantities
Location From MH To MH Diam.
(in)
Length
(ft)
No. of
MH
Oak Street
1652-0383 1652-0386 8 309 1
1652-0386 1652-0388 8 136 2
1652-0388 1652-0393 8 161 1
Total 606 4

9.3.4 Buildout Limiting Capacity Areas - Watch List
Based on the results of the Buildout Scenarios, there are 5 pipeline segments identified for the Watch List, not including CIP pipelines. These pipelines are not identified as capacity deficient using the analysis criteria but have modeled d/D ratios above the recommended design criteria for both Buildout Scenario 1 and Buildout Scenario 2. As such, if these pipelines are replaced due to condition or capacity constraints, the diameter or slope should be increased to meet the recommended design criteria. Table 9-5 presents these Watch List sewer pipelines for the Buildout Scenario.

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
9-7 October 2024
Table 9-5
Watch List – Buildout Limiting Capacity Areas
Street Name From MH To MH
Diam.
(in)
Length
(ft) Slope
Existing
Flow
(gpm)
d/D
Ratio
Remaining
Capacity
(gpm)
Pennsylvania
Ave
1652-0544 1652-0546 8 69 0.0010 100.3 0.53 41.6
1652-0567 1652-0575 10 88 0.0010 158.5 0.53 69.5
Cypress St 1652-0476 1652-0475 8 48 0.0020 112.9 0.51 57.8 1652-0612 1652-0466 10 100 0.0010 145.5 0.52 67.6
Eshelman Ave 1652-0323 1652-0318 8 55 0.0020 100.6 0.50 57.6

9.3.5 CCTV Review and Evaluation
The last Condition Assessment Program Report for the City of Lomita system is dated February 5, 2019. The report documents the review of CCTV inspection for 100 percent of the City’s sewer system that took place in 2013 and provides pipeline grading based on observed defects. The CSMD completed the latest CCTV inspection between April and December 2021 but, currently, the Condition Assessment Program Report has not been completed. The CSMD expects the completed report to be available later this year.

The 2013 inspection revealed approximately 10.5 percent of the pipe segments (89 segments) had a Pipeline Assessment and Certification Program (PACP) structural grade of 4 or 5 which indicates severe structural defects and the need for corrective action. The Report stated that corrective action would be programmed over the next 24-month period as part of the ongoing Accumulative Capital Outlay Program. Of the segments with structural grades of 4 or 5, 56 were classified as “no action needed” under the proposed corrective action. Once the Condition Assessment Program Report is completed by CSMD for the 2021 inspection, it is recommended to review the CCTV videos for the segments identified by the CSMD with the most significant structural defects (Defect Grade 4 or 5) and classified as “no action needed.” It is also recommended to review the videos for any pipelines identified as having sags or other potential capacity issues. Review of these segments will allow for independent recommendations to compare with the County methodology and recommendations.

9.4 Capital Improvement Prioritization and Costs
It is recommended that the PCH to Ebony Capital Improvement (CIP #1) be the highest priority of the three projects outlined in the previous section. The pipeline is nearing capacity and has structural damage identified in CCTV review. The pipeline was constructed in the 1930s and the alignment through back yards creates maintenance and access issues. This CIP is prioritized as it will require long-term planning beginning with a pre-design analysis and report to evaluate feasibility and develop a recommended alternative. It is estimated that approximately 30 manholes will need to be surveyed for invert and rim elevations along the cross-streets served by the back yard pipeline, Walnut Street, Ebony Lane, and the outfall to the San District as part of the analysis.

CCTV review is also recommended to locate sewer laterals prior to design. Due to the extended time frame of this CIP, the other two recommended CIPs may be constructed during the planning

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
9-8 October 2024
process as funding permits. Additionally, a near-term capacity solution has been provided (DIV #1) to divert flows away from the back yard pipeline to the San District trunk sewer along Western Avenue.

The second priority CIP is the pipeline replacement along 248th Street (CIP #2). The identified segment has a sag and is hydro cleaned by the CSMD every three to four months. It is recommended to review the most recent CCTV inspection prior to improvement as well as for the downstream pipelines along 248th Street, from Cypress Street to the outfall at Eshelman Avenue, to determine if the pipeline replacement project should be expanded in the area due to structural defects. The hydraulic analysis shows sufficient capacity along these pipelines based on flow data collected during the flow monitoring program.

The third priority CIP on Oak Street (CIP #3) is to correct a flat slope between PCH and 256th Street (MH1652-0386 to MH1652-0388) by replacing the pipeline along with the adjacent segment(s) to provide sufficient slope. The hydraulic analysis shows existing capacity in the pipeline under existing peak flow conditions with the pipeline flowing full under buildout peak flow conditions. A CCTV inspection is also recommended to locate the sewer laterals prior to design of the pipelines.

The Engineer’s opinion of the probable construction cost is shown in Table 9-6 below for each of the recommended capital improvement projects, based on the May 2024 Los Angeles Engineering News-Record (ENR) Construction Cost Index 15250. The tables include pipe unit costs per LF and estimated manhole costs. The estimated total cost includes the construction costs plus 45% for Professional Services and Contingencies (15% for design and technical services; 10% for administration, construction management, inspection, and project administration; and 20% for contingencies).

As new development projects within the City are proposed, sewer studies are recommended to evaluate projected flow and downstream sewer capacity. If the proposed development is tributary to pipelines that do not include as-built slope data in the City’s hydraulic model, these pipelines may be updated as part of the sewer study. The same would be true for pipeline replacement for structural damage. The CSMD maintains and repairs pipelines, however, the City is responsible for capacity enhancements and pipeline/manhole replacement. Where multiple defects such as cracks or sags are experienced, removal and replacements are typically recommended. These remove and replace segments should be coordinated with the CSMD and sized to provide capacity for buildout flows. In this way, the City’s sewer model will continue to be updated and provide a useful tool to ensure sufficient capacity now and moving forward.

CITY OF LOMITA

SANITARY SEWER SYSTEM MASTER PLAN
9-9 October 2024
Table 9-6
CIP Cost Estimates
CIP Street
Diam.
(in)
Length
(LF)
Pipe
Unit
Cost
($/LF)
No.
of
MH
MH
Unit
Cost
($/MH)
Estimated
Construction
Cost(1)
Professional
Services and
Contingencies(2)
Estimated
Total Cost
1 Ebony/Walnut 15 3,350 $550 16 $15,000 $2,082,500 $937,125 $3,019,625 Cross Streets 8 6,425 $450 32 $15,000 $3,371,250 $1,517,063 $4,888,313 Total 9,775 48 $5,453,750 $2,454,188 $7,907,938
DIV 1(3) Western Ave. 8 250 $550 2 $15,000 $167,500 $75,375 $242,875 2 248th St. 8 320 $450 2 $15,000 $174,000 $78,300 $252,300 3 Oak Street 8 600 $450 4 $15,000 $330,000 $148,500 $478,500 Total 10,945 56 $6,125,250 $2,756,363 $8,881,613
(1) Based on the May 2024 Los Angeles Engineering News-Record (ENR) Construction Cost Index of 15250. (2) Equal to 45% of the construction cost and includes 15% for design and technical services, 10% for administration, construction management, and inspection, and 20% for contingencies. (3) Near-term flow diversion improvement for CIP #1. Unit cost for 8-inch pipeline is higher due to construction across Western Avenue.

APPENDIX A

LOMITA SEWER CONDITION ASSESSMENT

PROGRAM REPORT

COUNTY OF LOS ANGELES

DEPARTMENT OF PUBLIC WORKS
"To Enrich Lives Through Effective and Caring Service"
MARK PESTRELLA, Director
February 5, 2019
Mr. Mark McAvoy
Director of Public Works
City of Lomita
24300 Narbonne Avenue
Lomita, CA 90717
Attention Mr. Mondher Saied
Dear Mr. McAvoy:

CONSOLIDATED SEWER MAINTENANCE DISTRICT

CONDITION ASSESSMENT PROGRAM REPORT
PROJECT NO. YOTV1112C

IN REPLY PLEASE
REFER TO FILE: SM—~
This letter is to inform you that the Los Angeles County Public Works Consolidated Sewer Maintenance District has completed a condition assessment of the City of Lomita's sewer system.

The enclosed Condition Assessment Report provides details regarding the maintenance and structural condition of your sewer mainlines. The information contained in the report should be included in your agency's Sewer System Management Plan as a reference in Chapter 8, System Evaluation and Capacity Assurance Plan.

The segments with critical maintenance issues have been cleaned and, where appropriate, incorporated into our enhanced maintenance schedule for continued monitoring. In addition, segments with severe structural defects have either been repaired or will be scheduled for corrective action as part of the ongoing Accumulative 900 SOUTH FREMONT AVENUE
ALHAMBRA, CALIFORNIA 9(803-1331
Telephone: (626)458-5100
http://dpw.lacounty.gov ADDRESS ALL CORRESPONDENCE TO:

P.O. BOX 1460
ALHAMBRA, CALIFORNIA 91802-1460
Capital Outlay Program.

Mr. Mark McAvoy
February 5, 2019

Page 2 ends

If you have any questions regarding this report or the Condition Assessment Program, please contact Ms. Kari Eskridge, Sewer Maintenance Division, at (626) 300-3390, Monday through Thursday, 7 a.m. to 5 p.m., or at keskridge(c~dpw.lacounty.qov.

Very truly yours,

MARK PESTRELLA
Director of Public Works
~~~ ~~~~
WILLIAM J. WINTER
Assistant Deputy Director
Sewer Maintenance Division
CK:nv
H:\SMHOME\SEWER\2019\LETTERS 8 MEMOS\1184.DOCX
Enc.

CONDITION ASSESSMENT REPORT

LOS ANGELES COUNTY PUBLIC WORKS

CONSOLIDATED SEWER MAINTENANCE DISTRICT
100% SUMMARY
SUP. 4 CITY: Lomita

DISTRICTS)
Report By: Clement Khong Report Date: 1/7/2019

I NTRODUCTION
As part of the Sewer Condition Assessment Program, Los Angeles County Public Works Consolidated Sewer Maintenance District (District) has completed the closed-circuit television inspection of 186,796 feet or 100 percent of the City of Lomita's (City) sewer system.

SUMMARY MAINTENANCE REPORT
Our inspection revealed that approximately 50.6 percent of the system televised was free of significant blockages or restrictions that would impede sewer flows. The remaining

49.4 percent of the inspected pipe segments within the City had a Pipeline Assessment and Certification Program (PACP) maintenance grade of 3, 4, or 5 as indicated in the Quick Maintenance Rating Table shown below. These segments have been addressed with corrective action taken as noted in the enclosed reports.

QUICK MAINTENANCE RATING TABLE

DEFECT PIPE LENGTH PERCENT TOTAL
NO. OF

GRADE (FT) INSPECTED PIPE

SEGMENTS LENGTH
1: Minor 69,916 37.4 350
2: Minor to Moderate 24,578 13.2 118
3: Moderate 35,380 18.9 159
4: Significant 54,371 29.1 230
5: Most Significant 2,551 1.4 15
TOTAL 186,796 100.0 872

Page 1 of 2 ends

SUMMARY STRUCTURAL REPORT
Our inspection revealed that approximately 89.5 percent of the inspected pipe segments within the City were free of significant structural defects. The remaining 1 0.5 percent of the inspected pipe segments had a PACP structural grade of 4 or 5 as i ndicated in the Quick Structural Rating Table shown below. The priority lists for these items are located in the enclosed reports.

QUICK STRUCTURAL RATING TABLE

DEFECT PIPE PERCENT TOTAL
NO. OF

GRADE LENGTH (FT) INSPECTED PIPE

SEGMENTS LENGTH
1: Minor 129,736 69.5 607
2: Minor to Moderate 14,458 7.7 70
3: Moderate 23,006 12.3 106
4: Significant 14,386 7.7 62
5: Most Significant 5,210 2.8 27
TOTAL 186,796 100.0 872

Page 2 of 2 ends

CONDITION ASSESSMENT REPORT

LOS ANGELES COUNTY PUBLIC WORKS

CONSOLIDATED SEWER MAINTENANCE DISTRICT
PROJECT NAME: YOTV1112C PROJECT MGR: Eric Liu
PROJECT DATE: 2/12/13 CONTACT NO: (626) 300-3369
SUP. DISTRICT(s): 4 MAP PAGE(S): 1651, 1652, 1653
Reaort Bv: Clement Khona Reaort Date: 1/7/19

I NTRODUCTION
Los Angeles County Public Works Consolidated Sewer Maintenance District (District) conducted a condition assessment of 186,796 feet or 100.0 percent of the City's entire sewer system as part of Project No. YOTV1112C.

The enclosed Condition Assessment Report outlines the structural and maintenance ratings of your system based on the PACP's (Version 6.0.1) rating methodology.

I ncluded in the report are the following:
• Project Overview Map (Enclosure 1)
• Quick Maintenance Rating Map and High Water Levels List and Map (Enclosure 2)
• Quick Structural Rating Report Priority List and Quick Structural Rating Map (Enclosure 3)
The Sewer Condition Assessment Program utilizes the PACP Quick Rating methodology to rank the structural and maintenance condition of your system based on industry standards.

PROJECT AREA AND DESCRIPTION
Project No. YOTV1112C included sewer lines located in the unincorporated County of Los Angeles County and the Cities of Lomita, Rolling Hilis, Rolling Hills Estates, Rancho Palos Verdes, and Paramount. Enclosed for your reference is an overview map of the project area within your City (Enclosure 1).

Page 1 of 4 ends

DEFECT GRADE DESCRIPTION
The Quick Rating indicates the number of occurrences for the highest severity grade for each pipe segment for either maintenance or structural defects. A grade of 1 indicates that a pipe segment is in excellent condition with minor defects while a grade of 5 indicates that a pipe segment may require immediate attention. A legend of the five possible defect grades is as follows:

Grade Defect Grade Descri tion
1: MINOR
2: MINOR TO MODERATE
3: MODERATE
4: SIGNIFICANT
5: MOST SIGNIFICANT

MAINTENANCE REPORT
Our inspection revealed that approximately 50.6 percent of the system televised in your City as part of Project No. YOTV1112C was free of significant blockages or restrictions that would impede sewer flows. The remaining 49.4 percent of the pipe segments within the City had a PACP maintenance grade of 3, 4, or 5 as indicated in the Quick Maintenance Rating Table shown below. These segments have been incorporated into our periodic cleaning schedule with corrective action taken.

A color-coded map showing the quick maintenance rating for each pipe segment is provided in Enclosure 2.

QUICK MAINTENANCE RATING TABLE

PIPE LENGTH PERCENT OF
NO. OF DEFECT GRADE (FT) TOTAL INSPECTED

SEGMENTS PIPE LENGTH
1: Minor 69,916 37.4 350
2: Minor to Moderate 24,578 13.2 118
3: Moderate 35,380 18.9 159
4: Significant 54,371 29.1 230
5: Most Significant 2,551 1.4 15
TOTAL 186,796 100.0 872

Page 2 of 4 ends

High Water Levels
Our inspection revealed that approximately 99.2 percent of the system televised has adequate capacity. Approximately 0.8 percent of the segments inspected exhibited visual signs associated with high water levels. The capacity of the sewer pipe can be determined by analyzing several PACP codes, including Water Level, Water Mark, and miscellaneous remarks, which indicate the camera was underwater or there were sags in the line. A sewer pipe is considered at capacity when 50 percent of the diameter of the sewer pipe is full of water. However, there are conditions in which the Water Level or Water Mark has reached 50 percent or greater due to heavy flows in adjoining pipes, a temporary stoppage caused by debris in the sewer lines, or a sag in the line.

Therefore, additional review of these pipe segments was conducted to determine if any capacity issues exist.

All sewer pipes where the Water Level, Water Mark, and miscellaneous remarks of camera underwater or sags in the line are at or above 50 percent capacity have been l isted and analyzed on the High Water Level Table in Enclosure 2. The nature of these high water level conditions is also summarized on this table.

A map showing the sewer lines with high water levels is provided in Enclosure 2.

Infiltration
Our inspection revealed that infiltration was not detected in any pipe segments in your City's system.

STRUCTURAL REPORT
Our inspection revealed that approximately 89.5 percent of the inspected pipe segments within the City were free of severe structural defects. The remaining

10.5 percent of the inspected pipe segments had a PACP structural grade of 4 or 5 as i ndicated in the Quick Structural Rating Table shown below. These segments have been placed on a priority list based on the severity and the need for action. For items 1 through 89 in the Quick Structural Rating Report Priority List (Enclosure 3), which warrant a corrective action, the proposed corrective action will be programmed in the next 24 months as part of the ongoing Accumulative Capital Outlay Program.

A color-coded map showing the Quick Structural Rating for each pipe segment is located i n Enclosure 3.

Page 3 of 4 ends

QUICK STRUCTURAL RATING TABLE

DEFECT PIPE LENGTH PERCENT TOTAL
NO. OF

GRADE (FT) INSPECTED PIPE

SEGMENTS LENGTH
1: Minor 129,736 69.5 607
2: Minor to Moderate 14,458 7.7 70
3: Moderate 23,006 12.3 106
4: Significant 14,386 7.7 62
5: Most Significant 5,210 2.8 27
TOTAL 186,796 100.0 872

CONDITION ASSESSMENT PROJECTS
The Sewer Condition Assessment Program performed the condition assessment of the sewer lines within the City according to the following schedule:

FISCAL PROJECT LENGTH PERCENTAGE

STATUS YEAR NAME (FT) OF SYSTEM
2011-12 YOTV1112C 186,796 100.0 COMPLETED
TOTAL 186,796 100.0

Page 4 of 4 ends

ENCLOSURE 1:

Project Overview Map
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Lomita
Torrance
Los Angeles
Rolling Hills Estates
Unincorporated
Unincorporated
Rolling Hills Rancho Palos VerdesS WESTERN AV OAK ST

LOMITA BLVD

WALNUT ST

S VERMONT AV

CRENSHAW BLVD

S NORMANDIE AV
W 253RD ST

NARBONNE AV

CYPRESS ST

AIRPORT DR

BNSF RR

PENNSYLVANIA AV
255TH ST

SKYPARK DR

W ANAHEIM ST
*****
238TH ST

W LOMITA BLVD

PALOS VERDES DR N
W 250TH ST

ROLLING HILLS RD
W 255TH ST
W 254TH ST

PACIFIC COAST HWY
W 259TH ST
W 256TH ST
W 257TH ST
240TH ST
W 259TH PL
239TH ST
W 247TH ST
W 252ND ST
W 251ST ST
263RD ST

FRAMPTON AV

W PACIFIC COAST HWY

WINLOCK RD
W 242ND PL

FEIJOA AV

N GAFFEY ST

ESHELMAN AV

LUCILLE AV
W 261ST ST

CREST RD

NEWTON ST

PALOS VERDES DR E
W 263RD ST
241ST ST
L ST
247TH ST
242ND ST

WOODWARD AV

ATHENA AV

LOFTYVIEW DR

DALEMEAD ST
W 260TH ST
W 240TH ST

REGENT AV

EAST DR

EBONY LN

OZONE AV

ANDREO AV

KOLEETA DR

STONEBRYN DR

GOVERNOR AV

CLUB VIEW LN

SENATOR AV

HUBER AV
261ST ST

ENCANTO DR
W 262ND ST

OAKHORNE DR

CAYUGA AV

BRIAN AV

DELOS DR

PONY LN

PRESIDENT AV
260TH ST

FERNREST DR

WINDMILL RD

WEST DR

ZEPHYR AV
251ST ST

SKYLINE DR

SOUTH DR

VIA MADONNA
243RD ST

GARNIER ST

ROLLING VISTA DR

RIDGELAND RD

HIDDEN LN

PENNSYLVANIA DR

DOBLE AV

ASHBRIDGE LN

CM LARGO

GRAND SUMMIT RD

MCCOY AV
245TH ST

ALLIENE AV

BELLE PORTE AV
H ST

AURORA DR
RD 12

VIA DESMONDE

ROLLING HILLS WY

MONTECILLO DR

CRICKLEWOOD ST
262ND ST

DANAHA ST

VIANA AV

DEL MAR

NEARCLIFF ST
W 247TH PL
W 249TH ST

CIRCLE DR
W 265TH ST

PETROLEUM AV

MOON AV
W 244TH ST

PASATIEMPO LN

NORTH DR
249TH ST
246TH ST
253RD ST

BUCKSKIN LN

OAKWOOD LN
W 253RD PL
W 266TH ST

FULMAR AV ALTA VISTA AV
W 246TH ST
256TH ST
W 248TH ST
254TH ST
257TH ST

VIS GRANDE

TANDEM WY

BAYSIDE PL
252ND ST
W 245TH ST

CALLE RD

DORIA AV
5TH AV E

MATFIELD DR

CENSOR AV

HIGHCROSS DR
W 246TH PL

APPIAN WY

WESTON RD

BROADWELL AV
W 258TH PL

DENNY RD
4TH AV E

DAPPLEGRAY LN

VIA MARQUETTE

LARIAT LN

EMPTY SADDLE RD
242ND PL
W 264TH ST

AGAJANIAN DR

BRIDLEWOOD CIR
3RD AV E

CM VERDE
1ST AV E

FALLENLEAF DR

VIS REAL DR
2ND AV E WINLOCK DR WEST AV

JANUARY DR

AVD BONITA

FAIRVIEW AV

LEESDALE AV

CAROLWOOD LN

BIXBY AV
244TH ST

ASHPARK LN

ARLINGTON AV

PINTO LN

FALENA AV

HILLWORTH AV

LOYTAN ST

DORADO PL

AMSLER ST
W 243RD ST

GLENTREE DR

LAZY MEADOW DR

RAINTREE AV

FERNLAKE DR

AMBER LEAF RD

PALOMINO LN

HUNT TER

WHIFFLETREE LN

S CIRCLE

LOMITA DR

BIGELOW RD
6TH AV E

E CIRCLE

CM VEGA

PARKSIDE TER

CELESTE PL

PORTOBELLO DR

BLAND PL

DAWN ST

CHAPMAN ST
4TH AV W

MARKET PL

HARBOR VILLAGE DR

GUYSON ST

HARBOR HEIGHTS DR

HIGHCLIFF DR

EMPTY SADDLE LN

LOMITA PARK PL

HILLSIDE DR

TURRELL ST

KELLEY AV

CURTISS WY

MILAN LN

TANGLEWOOD LN

CLARELLEN ST

SUNNY GLEN RD

ASHBRIDGE DR

STRAWBERRY LN

CENTER AV N

NORDMAN ST

SUNNYFIELD DR

SADDLE VIEW RD

ABITA AV

CM RASO

SHADOW LN

STEED CT

BAYVIEW LN
5TH AV W

VIA NOVA

ABRAHAM TER

HENDRICKS AV

OCEAN VIEW AV

CM D MAYO

AVOCADO ST

STANHURST AV

CADIZ DR

MARIGOLD AV

USS MISSOURI ST

SPICEWOOD LN

HILLCREST AV

RICHVILLE DR

VISLOMA PL

WITTICK CT SKYLARK DR

BENHILL AV

BAYCREST LN

FLINT DR

ROBIN LN

LEOLA ST

REED DR

SINGLETREE LN

LAURA LEE LN

LANTANA PL

CERRITO PL

SHADOWBROOK TER

W CIRCLE

USS ANTIETAM ST

OAKBAY RD

USS PRINCETON CT

MORETON ST

ROBINSON WY

REED ST

ALCOR ST

ZAMPERINI WY

GARNER ST

CENTER AV S

ESHELMAN WY

ADAMO AV

PEBBLE DR

MCKENNA CT VINE AV

AUSTINBROOK CT
W 239TH ST
243RD PL

BANI AV

OAKFERN LN

ADAMITE TER

CYPRESS CIDR

SLATE AV

DORIA CT

LIVEWOOD LN

SPRUCE LAKE DR

MONTEREY CIR

OAKMERE DR

STONECLIFF LN

LOBBY CIR

LA MOUR CT

AUBREY LN

VIS LOMITA LN

GLENCOE WY

NEKO DR

VERONICA LN
*****
*****
*****
*****
*****

SENATOR AV
*****
*****
*****
*****
*****
*****
247TH ST
262ND ST

ALLIENE AV
*****
245TH ST

BANI AV

S WESTERN AV
*****
261ST ST
*****

S WESTERN AV
*****
*****
*****
254TH ST
*****
W 246TH ST
*****

CM VERDE
W 253RD PL
*****
*****
*****
*****
W 251ST ST

FRAMPTON AV
*****
W 247TH PL
*****
*****
238TH ST
*****
*****
241ST ST
W 255TH ST
*****
*****

MCCOY AV
251ST ST

BANI AV
*****
*****
*****
W 256TH ST

DANAHA ST

PRESIDENT AV
*****
W 245TH ST

DALEMEAD ST
253RD ST
***** ***** LUCILLE AV
W 244TH ST
W 248TH ST
*****
*****
W 257TH ST
256TH ST
238TH ST
253RD ST
*****
254TH ST
*****
*****

ESHELMAN AV
247TH ST
*****
*****
W 248TH ST
*****
*****
*****
*****
W 254TH ST

APPIAN WY
W 243RD ST

WOODWARD AV
238TH ST
*****
*****
245TH ST
*****
*****
*****
*****
254TH ST
W 255TH ST
243RD ST
*****
W 251ST ST

BANI AV

FALENA AV

AIRPORT DR
*****

PRESIDENT AV

LARIAT LN
*****
W 240TH ST

GOVERNOR AV
*****
*****
*****
*****

APPIAN WY
*****
*****
*****
*****
*****
*****
245TH ST
*****
*****
W 248TH ST
*****
*****
*****
*****

PALOS VERDES DR N
*****
*****
W 252ND ST
*****
*****
*****

BELLE PORTE AV
S-1652
S-1651
S-1598 S-1707
S-1597
S-1706
S-1653
S-1599
Legend
SMD Sanitary Sewers
SMD Sanitary Sewers
SMD Manholes
!U Other
Manhole Type
!( Standard
#* DROP
"±
Shallow
XW Trap
!? Siphon
ÍP SMD Pump Stations
Q3 SMD Treatment Plants
Trunk Sewerlines
Non SMD Sanitary Sewers
!( Non SMD Maintained MH
SMD Operations Maps

CCTV PROJECT AREA
September 2018
0 540 1,080 1,620 2,160
Feet
This map is intended only for internal operations of the Los Angeles County Sewer Maintenance Districts.

Los Angles County expressly disclaims any liability
for any inaccuracies which may be present in this
map. Data contained in this map is produced in
whole or part from the Thomas Bros. Maps® digital
database. This map is copyrighted, and reproduced
with permission granted, by Thomas Bros. Maps®.

OVERVIEW MAP

CITY OF
LOMITA

CCTV PROJECT
Y0TV1112C
ENCLOSURE 2:
• Quick Maintenance Rating Map
• High Water Levels List and Map
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8 5
6 9
1 2 3 4
7 22
92 91
86 64
54 77
76 60
15 45
13 40
11 66
77 93 23
84 80
81 52
51 43
61 10
57 32
67 42
59 34
55 30 31
83 88 95
19 47
39 35 29 94
78 89
96 85
79 73
70 50
33 14
12 36
86 56
99 98
90 20
82 7172
53 62
68 65
2425
87 16 18
78 75
63 69
46 49
21 97
17 74
48 58
41 44
38 37
294
136
117
106 107
210
283
305
595
219
290
296
189
182
227
180
166
160
157
165
113
207
124 139
140
181
308
323 298
413
229 330
256
202
201
292
377
407
394
397 398
381
313
298
261
250
243
439
467
445
432
448
484
485
463 462 456
308307
311
196
584
580
486
556
552
487 544
190
560
571
559
118
132
213
207
200
617
228
222
223
192 191
156
174
149
168
156
170
167
168
172
291
153
187175164
182
204
291 292
297
329
162
280 281
275
410
396
371
253
242 260
237
219
217
401
468
472
450
514
310
228
223
234
318
193
563214 557 470
489
511
578
615
554
549
531
112
121
102
120
110
101
126
238
241
284
100
213
211
204
220
197
303
181
234
235
165
155
169
166
290
161
189
114
206
179
205
313
317
421
321
186
321
411
416
406
408
251
433
389
230
581
474
567 566
239
473
479
597
508 488
586
614
547
137
111
133
134
115
240
218
590
209
198
244
245
224
184
232
282 157
148
150
177
130
208
306
423
294
310
420
283
270
409
404
388
393
332 379 383 378
264
246 231
247
314
437
436
469 434
475
449
451
483
454
490
194
613
471
555
537
587
572
561
548
538 542 540
534
536
148
144
108
217
237
194
300
158
174
171
289
142 143
131
309
312
414
322
230
335
288
279
185
272 267
183
417
427
402
390
385
375
245
232
244
476
447
461
596
224
195
376
583
558
192
588
568
529
539
535
159
146
147
103
211
302
287
212
208
201
206
243
193
225
233
231
170
155
173
179
173
315
141
188
129
180 301
307
301 299
311
327
320
178
611
177
175
340
286
284
319
320
271
269
278
322
426
430
429
419
418
326
387
337 331
386
265
252
249
236239
235
466
395
229
226
222
317
574
545546
507
528
191
577 579
550
530
135
145
119
127
215
203 202
205
196
293
183
226
186
153
169
154
167
152
176
184
215
123
122
302
300 324
176
163
287
276
268
258
400
405
428
399
391
263
266
259
241
218
238
293
612
442
435
446
482
380
312
221
620 621
576
480
477
553
593
527
573
594
138
105
116
125
285
591
210
616
242
188
190
185
187
236
161
151
282
316
154
162
178
274
128
216
214
289
286
305
315
422
295
328
164
339 334
338
285
273
257
203
277
415
403
325
392
384
336
255
254
262
240
444
481
374
227
233
220
582
585
575
565
491
564
551
512
506
569 570
Lomita
Torrance
Los Angeles

LOMITA BLVD

WALNUT ST
OAK ST
237TH ST

S WESTERN AV

NARBONNE AV

CRENSHAW BLVD
236TH PL

PRESIDENT AV

PENNSYLVANIA AV

CYPRESS ST
238TH ST
W 250TH ST *****
W 255TH ST
W 254TH ST
W 256TH ST
W 257TH ST
W 253RD ST
239TH ST
W 247TH ST
W 259TH ST

SKYPARK DR
W 252ND ST
W 251ST ST

AIRPORT DR
W 242ND PL

BELLE PORTE AV

FEIJOA AV

ESHELMAN AV
247TH ST
242ND ST

WOODWARD AV
W 240TH ST

DALEMEAD ST

ANDREO AV

W LOMITA BLVD

BNSF RR

LUCILLE AV

HUBER AV

GARNIER ST

BRIAN AV
AVE F
AVE A
AVE G
AVE E
AVE D

SENATOR AV

CABRILLO AV
AVE C

ALLIENE AV

ROLLING HILLS WY
W 247TH PL
W 249TH ST

ARLINGTON AV
237TH PL

MOON AV
W 244TH ST

PACIFIC COAST HWY
249TH ST

FULMAR AV

W PACIFIC COAST HWY
W 246TH ST
W 248TH ST

CREST RD
W 245TH ST

DORIA AV
AVE B
242ND PL

CALLE RD

JANUARY DR

NEARCLIFF ST APPIAN WY

AVD BONITA

KIPPEN ST

VIANA AV

OAKHORNE DR

FALENA AV
W 243RD ST

VINE AV

DEL MAR

DANAHA ST

HILLSIDE DR

CLARELLEN ST
2ND ST

ABITA AV

NORMALLIN ST

WALTER AV

STANHURST AV

HYNFORD PL

GOVERNOR AV

FAIRCROSS ST

LAURA LEE LN
W 242ND ST

WINLOCK RD

ADAMO AV
W 239TH ST

RUTGERS PL

CENSOR AV

BANI AV

MAIDSTONE PL

DORIA CT

COMAL CT

LOBBY CIR

LA MOUR CT

LUCILLE AV
*****

WOODWARD AV

FALENA AV
W 243RD ST
*****
W 240TH ST

S WESTERN AV
*****

PRESIDENT AV
*****

SENATOR AV
238TH ST 238TH ST

VINE AV
W 245TH ST
*****
*****
*****
*****
W 244TH ST
*****
*****

FALENA AV
*****
*****
237TH ST
*****
*****

ALLIENE AV
*****
*****

S WESTERN AV
*****
*****
*****
*****
*****
238TH ST
237TH PL
*****
*****

AIRPORT DR
*****

LUCILLE AV
*****

ALLIENE AV
S-1651
S-1652
S-1597
S-1598
Legend
SMD Sanitary Sewers
QMR
1: MINOR
2: MINOR TO MODERATE
3: MODERATE
4: SIGNIFICANT
5: MOST SIGNIFICANT
SMD Manholes
!U Other
Manhole Type
!( Standard
#* DROP
"±
Shallow
XW Trap
!? Siphon
ÍP SMD Pump Stations
Q3 SMD Treatment Plants
Trunk Sewerlines
Non SMD Sanitary Sewers
!( Non SMD Maintained MH
SMD Operations Maps
CCTV Project Area
September 2018
0 360 720 1,080 1,440
Feet
This map is intended only for internal operations of the Los Angeles County Sewer Maintenance Districts.

CCTV PROJECT
Y0TV1112C
ENCLOSURE 2
QUICK

MAINTENANCE
RATING
(QMR)

CITY OF
LOMITA
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Lomita Torrance
Los Angeles
Rolling Hills Estates
Rancho Palos Verdes
OAK ST

S WESTERN AV
255TH ST
*****

PACIFIC COAST HWY

CYPRESS ST

PALOS VERDES DR N
W 259TH PL
W 257TH ST
W 256TH ST
W 255TH ST
W 254TH ST

NARBONNE AV
W 253RD ST

WALNUT ST
W 259TH ST

ESHELMAN AV

LUCILLE AV
W 261ST ST

PENNSYLVANIA AV

PALOS VERDES DR E
W 263RD ST

ATHENA AV

REGENT AV

CRENSHAW BLVD
W 260TH ST

OZONE AV

GOVERNOR AV

CLUB VIEW LN

W ANAHEIM ST

AIRPORT DR

DALEMEAD ST

SENATOR AV
261ST ST

ENCANTO DR
W 262ND ST

CAYUGA AV

BRIAN AV

DELOS DR

PRESIDENT AV

ZEPHYR AV

SKYLINE DR

FEIJOA AV

WOODWARD AV

PENNSYLVANIA DR

BELLE PORTE AV

AURORA DR
262ND ST

VIANA AV

DEL MAR

MONTECILLO DR
W 265TH ST
253RD ST
W 266TH ST

PARK VIEW DR

ALTA VISTA AV

BUCKSKIN LN

VIS GRANDE

CALLE RD

W PACIFIC COAST HWY

NEARCLIFF ST

CREST RD

MONTE VISTA AV

ANDREO AV

APPIAN WY

BRIDLEWOOD CIR

DAPPLEGRAY LN

MATFIELD DR

VIS REAL DR

AVD BONITA

FAIRVIEW AV

LEESDALE AV

HILLWORTH AV

DORADO PL

DORIA AV

CM VEGA

CELESTE PL

MARKET PL

ALLIENE AV

USS NEW JERSEY ST

PEACOCK LN

SILVERBIT LN

CLARELLEN ST

SADDLE VIEW RD

EVANS CT

AVOCADO ST

PALM CANYON DR

HILLCREST AV

RICHVILLE DR

VISLOMA PL

FAIRCROSS ST

LANTANA PL

CERRITO PL

USS ANTIETAM ST

OAKBAY RD

USS MISSOURI ST

HIGHCLIFF DR

ADAMO AV

PINEKNOLL AV

MURAD AV

BANI AV

USS PRAIRIE CT

VIS LOMITA LN
*****
*****

PRESIDENT AV
*****
*****

AIRPORT DR
*****
*****
*****

SENATOR AV
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*****
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*****
*****
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*****
*****
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*****
*****
*****
*****

ESHELMAN AV
*****
*****
*****
*****
*****
S-1652
S-1653
S-1598
S-1599
Legend
SMD Sanitary Sewers
QMR
1: MINOR
2: MINOR TO MODERATE
3: MODERATE
4: SIGNIFICANT
5: MOST SIGNIFICANT
SMD Manholes
!U Other
Manhole Type
!( Standard
#* DROP
"±
Shallow
XW Trap
!? Siphon
ÍP SMD Pump Stations
Q3 SMD Treatment Plants
Trunk Sewerlines
Non SMD Sanitary Sewers
!( Non SMD Maintained MH
SMD Operations Maps
CCTV Project Area
September 2018
0 325 650 975 1,300
Feet
This map is intended only for internal operations of the Los Angeles County Sewer Maintenance Districts.

CCTV PROJECT
Y0TV1112C
ENCLOSURE 2
QUICK

MAINTENANCE
RATING
(QMR)

CITY OF
LOMITA
ITEM NO. QMR START MH END MH STREET OBSERVATION CORRECTIVE ACTION TAKEN (DATE COMPLETED)
1 4A00 1651-0019 1651-0292 248TH ST High water (219' to 311' ) Rodder (7/2/2015) 2 4221 1651-0248 1651-0247 NARBONNE AV Water mark: 60% Rodder (7/6/2015) 3 4121 1651-0305 1651-0210 LOMITA BV Water mark: 50% No maintenance action needed. 4 4111 1652-0154 1652-0157 CAYUGA AV Water mark: 50% No maintenance action needed. 5 4100 1651-0016 1651-0017 248TH ST Sag (60%): 4'-16' No maintenance action needed. 6 4100 1652-0287 1652-0590 WALNUT ST Water mark: 50% No maintenance action needed. 7 3122 1652-0242 1650-0241 ALLEY Sag (50%): 2'-8' No maintenance action needed.

ENCLOSURE 2

HIGH WATER LEVELS
CITY OF LOMITA (Y0TV1112C)
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16 17 19
210
305
292
242
590
157
247
287
154
241
248
Lomita
Torrance
Los Angeles
OAK ST

LOMITA BLVD

WALNUT ST

S WESTERN AV

NARBONNE AV

PRESIDENT AV
255TH ST

CYPRESS ST

PENNSYLVANIA AV

CRENSHAW BLVD
238TH ST
W 250TH ST *****
W 257TH ST
W 256TH ST
W 255TH ST
W 254TH ST
240TH ST
239TH ST
W 247TH ST
W 253RD ST
W 259TH ST
W 252ND ST
W 242ND PL
W 251ST ST

FEIJOA AV

ESHELMAN AV

SKYPARK DR
241ST ST
247TH ST
242ND ST

WOODWARD AV
W 240TH ST

EBONY LN

ANDREO AV
245TH ST

AIRPORT DR

LUCILLE AV

DALEMEAD ST

W LOMITA BLVD

HUBER AV

BRIAN AV
251ST ST
243RD ST

ALLIENE AV
W 247TH PL
W 249TH ST

MOON AV
W 244TH ST
249TH ST
246TH ST
253RD ST

SENATOR AV
W 253RD PL

FULMAR AV
W 246TH ST
256TH ST
W 248TH ST
254TH ST
257TH ST
252ND ST
W 245TH ST

NEARCLIFF ST CALLE RD

W PACIFIC COAST HWY

DORIA AV
W 246TH PL

APPIAN WY
W 258TH PL

VIANA AV
242ND PL

SKYLINE DR

DEL MAR

AVD BONITA

FALENA AV

AMSLER ST
W 243RD ST

CABRILLO AV

CAYUGA AV

PACIFIC COAST HWY

LOMITA DR

BLAND PL

DAWN ST

ARLINGTON AV

HILLWORTH AV

LOMITA PARK PL

TURRELL ST

KELLEY AV

MILAN LN

CLARELLEN ST

NORDMAN ST

CALLISON ST

ABITA AV

ALLBROOK ST

HENDRICKS AV

EVANS CT

STANHURST AV

CADIZ DR

ESTHER VIEW DR

GOVERNOR AV

DORMONT AV

FAIRCROSS ST

BENHILL AV

ROBIN LN

LEOLA ST

JANUARY DR

REED DR

LAURA LEE LN
W 242ND ST

APRIL CT

PALM CANYON DR

MORETON ST

PARK HAVEN LN

REED ST

ALCOR ST
W 241ST ST

ESHELMAN WY

ADAMO AV

SUNNY LEAF LN

ADONA DR

MCKENNA CT

AUSTINBROOK CT
W 239TH ST
243RD PL

ELEANOR PL

VINE AV

BANI AV

FORRESTER DR

STRATFORD DR

AMBASSADOR DR

CYPRESS CIDR

COMAL CT

DORIA CT

PADRON PL

MONTEREY CIR

LA MOUR CT

AUBREY LN

NEKO DR

VERONICA LN

NOELLE CT

HILLVIEW LN

BECKNEL AV
252ND ST

BANI AV
W 246TH ST SENATOR AV
W 248TH ST

ESHELMAN WY
*****
238TH ST
253RD ST
*****
*****
W 253RD PL ***** *****
*****
256TH ST WOODWARD AV
W 248TH ST
242ND ST
*****

BANI AV

FALENA AV
*****

FORRESTER DR
*****
W 245TH ST
*****
253RD ST
*****
*****
*****
*****

BANI AV

S WESTERN AV
*****
*****

STANHURST AV
247TH ST

LUCILLE AV

S WESTERN AV
*****
*****

PRESIDENT AV

ALLIENE AV
254TH ST
247TH ST
W 240TH ST
*****
*****
*****
*****
W 247TH PL

AIRPORT DR
254TH ST
*****
*****
W 244TH ST
*****
241ST ST
W 248TH ST
*****
254TH ST
W 243RD ST
S-1651
S-1652
S-1597
S-1598
Legend

HIGH WATER LEVEL
SMD Manholes
!U Other
Manhole Type
!( Standard
#* DROP
"±
Shallow
XW Trap
!? Siphon
ÍP SMD Pump Stations
Q3 SMD Treatment Plants
Trunk Sewerlines
Non SMD Sanitary Sewers
!( Non SMD Maintained MH
SMD Operations Maps
CCTV Project Area
September 2018
0 330 660 990 1,320
Feet
This map is intended only for internal operations of the Los Angeles County Sewer Maintenance Districts.

CCTV PROJECT
Y0TV1112C
ENCLOSURE 2

HIGH WATER LEVEL

CITY OF
LOMITA
ENCLOSURE 3:
• Quick Structural Rating Report
Priority List
• Quick Structural Rating Map
ITEM NO. START MH END MH STREET OBSERVATION PROPOSED CORRECTIVE ACTION 1 1652‐0592 1652‐0370 OAK STREET Fractures, Broken Lining 2 1652‐0286 1652‐0590 ELEANOR PL Corrosion No action needed* 3 1652‐0245 1652‐0244 EBONY LN Broken No action needed*4 1652‐0275 1652‐0276 APPIAN WY Fractures Lining 5 1651‐0072 1651‐0071 247TH ST Fractures Lining
6 1651‐0029 1651‐0028 ESHELMAN AV Fractures, Hole Lining 7 1651‐0305 1651‐0210 LOMITA BV Broken Point repair
8 1652‐0280 1652‐0281 APPIAN WY Fractures, Broken Lining 9 1653‐0289 1653‐0288 EASEMENT Fractures, Broken Point repair 10 1652‐0508 1652‐0507 PACIFIC COAST HWY Broken No action needed* 11 1652‐0109 1652‐0110 262ND ST Fractures, Broken Point repair 12 1651‐0016 1651‐0017 248TH ST Hole Point repair
13 1652‐0350 1652‐0348 ESHELMAN AV Broken Point repair
14 1652‐0363 1652‐0364 OAK ST Fractures, Broken, Hole Point repair 15 1653‐0271 1653‐0272 ALLEY Broken No action needed*
16 1651‐0050 1651‐0051 248TH ST Broken No action needed* 17 1651‐0055 1651‐0056 EASEMENT Hole Point repair
18 1652‐0456 1652‐TRNK PACIFIC COAST HWY Broken No action needed* 19 1652‐0361 1652‐0362 OAK ST Broken No action needed*
20 1652‐0369 1652‐0592 OAK ST Broken No action needed*
21 1652‐0403 1652‐0404 WOODWARD AV Cracks No action needed* 22 1652‐0316 1652‐0315 ESHELMAN AV Broken Point repair
23 1652‐0204 1652‐0617 EASEMENT Broken No action needed* 24 1652‐0101 1652‐0102 ALTA VISTA AV Broken Lining
25 1652‐0131 1652‐0136 CAYUGA AV Hole No action needed* 26 1651‐0135 1651‐0134 FALENA AV Hole Yard investigation required 27 1651‐0079 1651‐0019 NARBONNE AV Broken Lining
28 1651‐0019 1651‐0292 248TH ST Cracks No action needed* 29 1651‐0157 1651‐0156 241ST ST Fractures Lining
30 1652‐0421 1652‐0422 ANDREO AV Fractures Lining
ENCLOSURE 3

QUICK STRUCTURAL RATING REPORT PRIORITY LIST
CITY OF LOMITA (Y0TV1112C)

Page 1 of 3 ends

ITEM NO. START MH END MH STREET OBSERVATION PROPOSED CORRECTIVE ACTION ENCLOSURE 3

QUICK STRUCTURAL RATING REPORT PRIORITY LIST
CITY OF LOMITA (Y0TV1112C)
31 1652‐0322 1652‐0323 253RD PL Fractures Lining
32 1651‐0011 1651‐0012 PENNSYLVANIA AV Fractures, Hole Lining 33 1651‐0095 1651‐0027 248TH ST Fractures No action needed* 34 1651‐0158 1651‐0157 241ST ST Fractures Lining
35 1652‐0422 1652‐0423 ANDREO AV Fractures Lining
36 1651‐0143 1651‐0142 TURRELL ST Fractures Lining
37 1651‐0144 1651‐0143 TURRELL ST Fractures Lining
38 1651‐0066 1651‐0066A MORENTON ST Fractures Lining
39 1651‐0036 1651‐0035 249TH ST Fractures, Broken Lining 40 1652‐0413 1652‐0414 ANDREO AV Fractures Lining
41 1652‐0510 1652‐0511 VIANA AV Fractures No action needed* 42 1652‐0319 1652‐0322 ANDREO AV Fractures Lining
43 1652‐0141 1651‐0142 R/W Tap intruding No action needed* 44 1651‐0065 1651‐0066 MORENTON ST Fractures No action needed* 45 1651‐0008 1651‐0011 247TH ST Fractures No action needed* 46 1651‐0066A 1651‐0067 MORENTON ST Broken Point repair 47 1652‐0104 1652‐0105 WESTERN AV Fractures Lining
48 1652‐0365 1652‐0369 OAK ST Fractures Lining
49 1651‐0156 1651‐0294 241ST ST Fractures No action needed* 50 1652‐0343 1652‐0344 EASEMENT Fractures No action needed* 51 1651‐0154 1651‐0153 CALLISON ST Fractures No action needed* 52 1651‐0092 1651‐0093 248TH ST Fractures No action needed* 53 1651‐0031 1651‐0030 FALENA AV Fractures No action needed* 54 1652‐0356 1652‐0357 GUYSON ST Fractures No action needed* 55 1652‐0252 1652‐0253 ESHELMAN AV Fractures No action needed* 56 1652‐0157 1652‐0170 CAYUGA AV Fractures No action needed* 57 1651‐0153 1651‐0146 CALLISON ST Fractures No action needed* 58 1651‐0093 1651‐0094 248TH ST Fractures No action needed* 59 1652‐0231 1652‐0232 WALNUT ST Fractures, Broken No action needed* 60 1651‐0007 1651‐0008 247TH ST Fractures No action needed*

Page 2 of 3 ends

ITEM NO. START MH END MH STREET OBSERVATION PROPOSED CORRECTIVE ACTION ENCLOSURE 3

QUICK STRUCTURAL RATING REPORT PRIORITY LIST
CITY OF LOMITA (Y0TV1112C)
61 1652‐0511 1652‐0512 VIANA AV Fractures No action needed* 62 1652‐0517 1652‐0516 CYPRESS ST Cracks No action needed* 63 1652‐0519 1652‐0520 CYPRESS ST Fractures No action needed* 64 1652‐0427 1652‐0428 WOODWARD AV Fractures No action needed* 65 1652‐0348 1652‐0347 ESHELMAN AV Fractures No action needed* 66 1652‐0349 1652‐0350 GARNER ST Fractures No action needed* 67 1652‐0240 1652‐TRNK EBONY LN Fractures No action needed* 68 1652‐0158 1652‐0159 259TH PL. Cracks No action needed* 69 1651‐0196 1651‐0195 LOMITA BV Cracks No action needed* 70 1652‐0541 1652‐0542 PACIFIC COAST HWY Fractures No action needed* 71 1651‐0035 1651‐0034 249TH ST Fractures No action needed* 72 1652‐0445 1652‐0446 ALLIENE AV Fractures Lining
73 1651‐0078 1651‐0019 NARBONNE AV Fractures No action needed* 74 1652‐0340 1652‐0339 ESHELMAN AV Hole No action needed* 75 1652‐0588 1652‐0586 250TH ST Fractures No action needed* 76 1652‐0428 1652‐0429 WOODWARD AV Fractures No action needed* 77 1652‐0451 1652‐0450 255TH ST Fractures No action needed* 78 1652‐0382 1652‐0383 PACIFIC COAST HWY Fractures No action needed* 79 1652‐0401 1652‐0404 253RD PL Fractures No action needed* 80 1652‐0346 1652‐0347 W. 259TH PL Fractures No action needed* 81 1652‐0163 1652‐0164 REED AV Fractures No action needed* 82 1652‐0184 1652‐0183 257TH ST Fractures No action needed* 83 1652‐0600 1652‐0110 WESTERN AV Fractures No action needed* 84 1652‐0100 1652‐0600 WESTERN AV Fractures No action needed* 85 1652‐0061 1652‐0062 VIA DESMONDE Fractures No action needed* 86 1651‐0111 1651‐0112 247TH PL Fractures Point repair
87 1651‐0145 1651‐0144 WALNUT ST Fractures No action needed* 88 1651‐0058 1651‐0059 EASEMENT Fractures No action needed* 89 1651‐0069 1651‐0068 PENNSYLVANIA AV Fractures No action needed*

Page 3 of 3 ends

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86 64
54 77
76 60
15 45
13 40
11 66
93 23
84 80
81 52
51 43
61 10
57 32
67 42
59 34
55 30 31
83 88 95
19 47
39 35 29 94
89 96
85 79
73 70
50 33
14 12
36 86
56 99
98 90 20
82 71 72
53 62
68 65
2425
87 16 18
78 75
63 69
46 49
21 97
17 74
48 58
41 44
38 37
294
136
117
106 107
210
283
305
595
219
290
296
189
182
227
180
166
160
157
165
113
207
124 139
140
181
308
323 298
413
229 330
256
202
201
292
377
407
394
397 398
381
313
298
261
250
243
439
467
445
432
448
484
485
463 462 456
308307
311
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584
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486
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190
560
571
559
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213
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200
617
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156
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172
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291 292
297
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280 281
275
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114
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179
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313
317
421
321
186
321
411
416
406
408
251
433
389
230
581
474
567 566
239
473
479
508
488
586
614
547
137
111
133
134
115
240
218
590
209
198
244
245
224
184
232
282 157
150
177
130
208
306
423
294
310
420
283
270
409
404
388
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332 379 383 378
264
246 231
247
314
437
436
434 469
475
449
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483
454
490
194
613
471
555
537
587
572
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534
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149
148
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108
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158
174
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289
142 143
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309
312
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322
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288
279
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272 267
183
417
427
402
390
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287
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208
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193
225
233
231
170
173
179
173
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141
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180 301
307
301 299
311
327
320
178
611
177
175
286
284
319
320
271
269
278
322
426
430
429
419
418
326
387
337
386
265
252
249
236 239
235
466
395
229
222 226
317
574
545546
507
191
577 579
550
135
145
119
127
215
203
202
205
196
293
183
226
186
167 169
152
176
184
215
123
122
302
300 324
176
163
287
276
268
258
400
405
428
399
391
263
266
259
241
218
238
293
612
442
435
446
482
453 380
312
221
620 621
576
480
477
553
573
594
138
105
116
125
285
591
210
616
242
188
190
185
187
236
151
282
316
154
162
178
274
128
216
214
289
286
305
315
422
295
328
164
339
334
338
285
273
257
203
277
415
403
325
392
384
336
255
254
262
248
240
444
481
374
225
227
233
220
582
585
575
565
491
564
551
512
569 570
Lomita
Torrance
Los Angeles

LOMITA BLVD

WALNUT ST
OAK ST

S WESTERN AV

ESHELMAN AV

NARBONNE AV
255TH ST

PRESIDENT AV

CRENSHAW BLVD

CYPRESS ST

PENNSYLVANIA AV
238TH ST
W 250TH ST *****
239TH ST
W 257TH ST
W 256TH ST
W 255TH ST
W 254TH ST
W 247TH ST
W 253RD ST

SKYPARK DR

FEIJOA AV
W 252ND ST
W 251ST ST
W 242ND PL

AIRPORT DR
247TH ST
242ND STWOODWARD AV

ANDREO AV

DALEMEAD ST

HUBER AV
W 240TH ST

W LOMITA BLVD

LUCILLE AV

PACIFIC COAST HWY

BRIAN AV

ALLIENE AV
W 247TH PL
W 249TH ST
237TH PL

MOON AV
W 244TH ST
249TH ST

FULMAR AV
W 245TH ST

DORIA AV

CABRILLO AV
242ND PL

ARLINGTON AV

W PACIFIC COAST HWY AVD BONITA

JANUARY DR

ROLLING HILLS WY

FALENA AV

AMSLER ST
W 243RD ST
AVE A
AVE G
AVE F
AVE E
AVE D
AVE C

VINE AV

HILLSIDE DR

NEARCLIFF ST
2ND ST

ABITA AV

NORMALLIN ST

VIANA AV

HENDRICKS AV

EVANS CT

STANHURST AV

CREST RD

GOVERNOR AV

KIPPEN ST

WALTER AV

LAURA LEE LN
W 242ND ST

FAIRCROSS ST CALLE RD
W 241ST ST

ADAMO AV

SENATOR AV
W 239TH ST

BANI AV

COMAL CT

DORIA CT

LA MOUR CT

HILLVIEW LN
*****

CYPRESS ST
242ND ST
238TH ST
*****

LUCILLE AV

SENATOR AV

S WESTERN AV

VINE AV
*****
*****

WOODWARD AV
W 240TH ST
*****
*****
*****
*****

FALENA AV

S WESTERN AV
*****
*****
*****

STANHURST AV
*****
*****

ALLIENE AV
*****
*****
*****

PRESIDENT AV
*****
*****

FALENA AV
*****
*****
238TH ST
238TH ST

AIRPORT DR
237TH PL
*****
*****
*****
*****

ALLIENE AV
S-1651
S-1652
S-1597
S-1598
Legend
SMD Sanitary Sewers
QSR
1: MINOR
2: MINOR TO MODERATE
3: MODERATE
4: SIGNIFICANT
5: MOST SIGNIFICANT
SMD Manholes
!U Other
Manhole Type
!( Standard
#* DROP
"±
Shallow
XW Trap
!? Siphon
ÍP SMD Pump Stations
Q3 SMD Treatment Plants
Trunk Sewerlines
Non SMD Sanitary Sewers
!( Non SMD Maintained MH
SMD Operations Maps
CCTV Project Area
September 2018
0 330 660 990 1,320
Feet
This map is intended only for internal operations of the Los Angeles County Sewer Maintenance Districts.

CCTV PROJECT
Y0TV1112C
ENCLOSURE 3
QUICK

STRUCTURAL
RATING
(QSR)

CITY OF
LOMITA
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66 73
46 48
91 93
96 77
55 60
59 50 68
63 98
99 97
62 57
47 78
74 58
45 53
86 89
64 70 69
71 72
76 61
94 95
56 75
49 51 52
87 90
67 54 65
37 189
182
227
180
145
166
600
130
138
105 106
229 330
141 279
122
121
115
253
275
265
394
397 398
342
381
618
364
260
445
432
448
484
485
463 462 456
486
556
552
544 487
492
532
522
192 191
156
174
149
168
281
110
135
128
101
126 609
329
162
158
274
118
116
255
267
396
371
344
358
343
368
355
365
363
362
256
263
262
450
514
489
511
524
497
498
554
549
531
181
234
235
165
113
604
143
102
103
127
159
276
250
287
370
288
367
354
622
361
272 271
270
288
389
460
457 518
479
597
508
488
598
504
494
547
523
184
232
147
282 157
146
148
111
100
139
131
606605
142
281
341
347
277
119
132
114
117 267 252
268276
273
286
388
393
345
332 379
383 378
366
623
619
449
451
483
454
490
555
505
537
525
503
548
538
542
540
534
533
536
160
109
136
608
230
335
133
275
125
402
390
385
375
357
369
257
265
289
447
461
596
515
458
509
496
529
539 535
225
233
231
170
155
173
179
108
150
140
602
129
607
327
178
611
177
175
340
137
124
349
251
272
266
326
387
337
386
382
360 359
356
259
395
459
521
599
545546
510
507
528
501
550
530
183
226
186
153
152
169
154
167
603
134
104
610
283
176
163
278
266
269
399
391
264
261
446
482
453 380
517
519
480
477
553
527
493
495
594
526
188
190
185
187
236
280
161
144 151
107
328
164
339
334
338
123
120
350
351
254
353
273
268
270
264
325
392
384
336
592
444
481
374
516
520
551 491
512
506
500
Lomita
Torrance
Rolling Hills Estates
Los Angeles
Rancho Palos Verdes
255TH ST

S WESTERN AV
OAK ST
*****

PALOS VERDES DR N
W 259TH PL
263RD ST

CYPRESS ST

LUCILLE AV

PALOS VERDES DR E

NARBONNE AV
W 257TH ST
W 256TH ST
W 255TH ST

WALNUT ST

REGENT AV
W 259TH ST

OZONE AV

GOVERNOR AV

CLUB VIEW LN
261ST ST

ENCANTO DR

PENNSYLVANIA AV

CAYUGA AV

BRIAN AV

ESHELMAN AV

DELOS DR

ZEPHYR AV

DALEMEAD ST

SKYLINE DR
W 261ST ST

ROLLING VISTA DR

PENNSYLVANIA DR

MONTECILLO DR

AURORA DR
262ND ST W 262ND ST
W 263RD ST

VIANA AV

DEL MAR

BUCKSKIN LN

ALTA VISTA AV
W 265TH ST

VIS GRANDE

CALLE RD
W 266TH ST

DAPPLEGRAY LN

MONTE VISTA AV

APPIAN WY

VIA MARQUETTE

BRIDLEWOOD CIR
W 260TH ST

NEARCLIFF ST

VIS REAL DR

W ANAHEIM ST

AVD BONITA

LEESDALE AV

HILLWORTH AV

DORADO PL

CRENSHAW BLVD

AIRPORT DR

PACIFIC COAST HWY

WOODWARD AV

CELESTE PL

PENINSULA VERDE DR

MARKET PL

ALLIENE AV

PEACOCK LN

MEMORIAL TERRACE DR

SILVERBIT LN

SADDLE VIEW RD

CREST RD

VIA NOVA

OCEAN VIEW AV

EVANS CT

AVOCADO ST

BAY MARE LN

PALM CANYON DR

W PACIFIC COAST HWY

MATFIELD DR

HILLCREST AV

RICHVILLE DR

VISLOMA PL

FAIRCROSS ST

LANTANA PL

CERRITO PL

USS ANTIETAM ST

REED ST

MURAD AV

OAKBAY RD

BANI AV

FORRESTER DR

CIRCLE VERDE DR

VIS LOMITA LN
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****
*****

ESHELMAN AV
S-1652
S-1653
S-1598
S-1599
Legend
SMD Sanitary Sewers
QSR
1: MINOR
2: MINOR TO MODERATE
3: MODERATE
4: SIGNIFICANT
5: MOST SIGNIFICANT
SMD Manholes
!U Other
Manhole Type
!( Standard
#* DROP
"±
Shallow
XW Trap
!? Siphon
ÍP SMD Pump Stations
Q3 SMD Treatment Plants
Trunk Sewerlines
Non SMD Sanitary Sewers
!( Non SMD Maintained MH
SMD Operations Maps
CCTV Project Area
September 2018
0 290 580 870 1,160
Feet
This map is intended only for internal operations of the Los Angeles County Sewer Maintenance Districts.

CCTV PROJECT
Y0TV1112C
ENCLOSURE 3
QUICK

STRUCTURAL
RATING
(QSR)

CITY OF
LOMITA

APPENDIX B

CCTV REVIEW AND RECOMMENDATIONS
Sources: Esri, HERE, Garmin, USGS, Intermap,
INCREMENT P, NRCan, Esri Japan, METI, Esri China
(Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c)
OpenStreetMap contributors, and the GIS User
Community
Legend
Manhole
<all other values>
TYPE
Active
Domain
Inactive
Outlet
<all other values>
TYPE
Active
Domain
Inactive
Gravity Main
<all other values>
TYPE
Active
Domain
Inactive
POINT_REPAIR

SEGMENTLINER
ROOTS
TOPHAT
World Street Map
Inactive
POINT_REPAIR

SEGMENTLINER
ROOTS
TOPHAT
World Street Map
Back Yard Pipeline
Pacific Coast Hwy. Ebony Ln. Walnut Street

SEGMENT LINER
Segment ID Direction
CCTV Length
(ft.)
Active
Laterals
High Water
Level Recommendation Notes Other Comments
0174/1652-0184/1652 D/S 342.2 5 (verify) 45% CIPP line pipe due to fractures, missing pipe wall, and joint offsets.

Missed FC at 97.2' D/S;
FM @175.8' D/S;
defective lateral JOM @ 261.6' D/S;
defective lateral FM @ 265.0' D/S;
missed FM @ 267.6' D/S;
missed FM @ 307.5' D/S;
FM @ 310.9' D/S;
wall missing at 105.8' & 112.7' D/S
0184/1652-0185/1652 D/S 180.0 3 25%
Remove root ball at 103.3' D/S;
remove roots in lateral at 105.4' D/S;
install top hat at 105.4' D/S;
CIPP line pipe due to root intrusion
throughout pipe.

RFJ @ 1.9', 7.0', 22.0', 37.5', 43.8', 52.5', 92.0', 97.0', 108.4', 112.0', 115.0', 121.0', 127.0', 133.0', 136.0', D/S;
RMJ @ 94.5', 101.0' D/S;
Root ball @ 103.3' (remove), 105.4' (in lateral, remove) D/S; Roots in barrel @ 92.4' (remove), 143.0', D/S
TFA @ 105.4', 146.5' D/S;
TBA @ 81.7' D/S;
0185/1652-0189/1652 D/S 185.4 3 30%
Point repair from 66-72' D/S due to
defective laterals and sag in pipe (2
TFY's); segment liner from 34-38' D/S
due to fracture.

Missed FC @ 36.6', 63.5', D/S;
Missed JOM @ 63.5' D/S;
Apparent sag from 65-70' D/S;
RFJ @ 18.5' D/S;
TFA @ 5.3', D/S;
TFD @ 65.9', 68.3' D/S (both have large offset, replace) Lateral defective such that repair should be performed if lateral is active.
0189/1652-0190/1652 D/S 183.5 3 20%
Point repair from 38-44' D/S due to
defective lateral (1 TFY); segment line
pipe from 132-136' D/S due to fracture.

Missed FL @ 134.1' D/S;
Missed CC @ 176.0' D/S;
TFA @ 107.4', 110.4', D/S;
TFD @ 41.4' (broken, replace wye) D/S;
Lateral defective such that repair should be performed if lateral is active.
0190/1652-0192/1652 D/S 181.9 2 40% Segment line from 22-26' D/S due to fracture
Missed FC @ 24.5' D/S,;
TFD @ 99.0' (broken, replace), 148.5' (JOL, top hat or replace? Review with Ben), D/S;
TFC @ 122.4'
TFYs are defective, but at 99.0' the break is at top of lateral and is thus lower priority; lateral is still
functioning ay 148.5' so also not as high priority.

Removed PR. Point repairs in this reach may be difficult to construct due to access restrictions. TFY at 122.4'
does seem to be intentionally plugged but would need
to confirm.
0192/1652-0193/1652 D/S 159.2 3 25%
Low Priority.

Segment line from 128-132' D/S due to
fracture.

Missed FC @ 130.0' D/S;
Missed TFA @ 108.0' D/S;
TFA @ 95.9'D/S;
TBA @ 104.7' D/S;
TFC @ 42.2' D/S;
High water level from 143-155' D/S (approx. 60%).
0193/1652-0194/1652 D/S 5.3 0 25% No repair recommended. N/A. Very short segment. 0194/1652-0201/1652 D/S 170.6 2 30%
No repair recommended. Suggest
monitoring deposits and roots in
defective laterals.

High water level for portions of inspection.

TFD @ 95.4' (heavy deposits), 125.4' (roots) D/S
Segment ID Direction
CCTV Length
(ft.)
Active
Laterals
High Water
Level Recommendation Notes Other Comments
0201/1652-0202/1652 D/S 228.4 3 25% Remove root ball at 6 locations; CIPP line pipe due to heavy root intrusion.

Root ball @ 125.0', 127.0', 137.0', 151.1', 160.5', 163.5', D/S'; RFJ @ 130.9', 133.5', D/S;
TFA @ 97.1', 102.6', 228.2' D/S;
0202/1652-0204/1652 D/S 22.4 1 15% No repair recommended. TFA @ 11.1' D/S; 0204/1652-0617/1652 D/S 97.7 1 20% No repair recommended. TFA @ 35.8' D/S; TFC @ 53.2' D/S;
0208/1652-0211/1652 D/S 290.4 2 35% No repair recommended.

Missed CC @ 1.5', 60.8', 67.2', D/S;
TFA @ 101.9', 128.7' D/S;
TFC @ 255.0', 257.5' D/S
0211/1652-0212/1652 D/S 228.2 3 35% Remove root ball at 14.3' D/S.

RFJ @ 5.8' D/S;
Root ball @ 14.3' (remove) D/S;
TFA @ 92.4', 174.6' D/S;
TBA @ 152.5' D/S;
TFC @ 116.4' D/S;
0212/1652-0217/1652 D/S 239.7 2 35% No repair recommended. TFA @ 14.5' D/S; TFC @ 116.5' D/S;
0208/1652-0616/1652 D/S 168.6 6 30% No repair recommended. TFA @ 14.5', 16.3', 43.9', 46.3, 91.5', 102.6', D/S; 0616/1652-0617/1652 D/S 37.5 1 30% No repair recommended. TFA @ 21.6' D/S

APPENDIX C
US3 FLOW MONITORING REPORT
2023.11 250th St MH
MH at ~2254 250th St
MH in eastbound lane on 250th street
north of address
X
Install Date: 11/06/2023
Access: System Type:

Sanitary Storm
Map
Sewer Map
Flow Meter
Meter Depth: 146.46"
MH Coordinates: 33.798224, -118.321994
Slow to moderate open channel hydraulics.

Avg Velocity Avg Measured Level Multiplier

1.9 fps 2.9" 1.0
Gas
O2 H2S CO LEL

20.9 0 0 0
Notes
No laterals; monitored the upstream line as it
provided the best hydraulics during inspection.

Traffic Safety
Used cones & signs in accord w/site-specific
CATTCH requirements.

Land Use
Residential Commercial Industrial Trunk
X
East
Manhole Depth
15"
168"
Round
15"/15"
Good
Brick
None observed
Passed

0.4 2-D

21.54"

6.54"
Upstream
Flow Heading
Sensor Direction
Sensor Dist. to Crown
Sensor Offset
Velocity Profile Data
Velocity Profile Taken
Silt
Manhole Material
Pipe Condition
Pipe Shape
Inner Pipe Size (In/Out)
Monitored Pipe Size
PSOMAS
Lomita, CA 90717
MH # unknown
Site Report
Confidential Proprietary Information
11/28/2023
2023.11 250th St MH
MH at ~2254 250th St
Lomita, CA 90717
Meter Site Document
Manhole Before Install
Installed
Upstream Pipe Size
Site
Installation Process
Upstream
Temporary Flow Study
PSOMAS
2023.11 250th St MH
Utility Systems, Science and Software
Santa Ana, CA 92705
601 N. Parkcenter Dr, Suite 209
Meter Start Date From 11/6/2023
Meter Stop Date To 11/22/2023
Velocity (fps) Level (in) Flow (mgd)
Average 1.865 2.948 0.215
Maximum 2.390 4.070 0.388
Minimum 1.030 1.800 0.056
Pipe Size 15.000
Estimated Capacity (mgd) Not Calculated
Capacity Used Not Calculated
Sensor Type Hach - Flodar
El Cajon, CA 92020
1300 Hill St
2023.11 248th St MH
MH at ~2120 248th St
MH in the center of 248th street north
of address
X
Install Date: 11/06/2023
Access: System Type:

Sanitary Storm
Map
Sewer Map
Flow Meter
Meter Depth: 128.07"
MH Coordinates: 33.799690, -118.318081
Slow to moderate open channel hydraulics
Avg Velocity Avg Measured Level Multiplier

1.0 fps 2.9" 1.0
Gas
O2 H2S CO LEL

20.9 0 0 0
Notes
No laterals; monitored the upstream line as it
provided the best hydraulics during inspection.

Traffic Safety
Used cones & signs in accord w/site-specific
CATTCH requirements.

Land Use
Residential Commercial Industrial Trunk
X
East
Manhole Depth
12"
148"
Round
12"/12"
Good
Brick
None observed
Passed

0.4 2-D

19.93"

7.93"
Upstream
Flow Heading
Sensor Direction
Sensor Dist. to Crown
Sensor Offset
Velocity Profile Data
Velocity Profile Taken
Silt
Manhole Material
Pipe Condition
Pipe Shape
Inner Pipe Size (In/Out)
Monitored Pipe Size
PSOMAS
Lomita, CA 90717
MH # unknown
Site Report
Confidential Proprietary Information
11/28/2023
2023.11 248th St MH
MH at ~2120 248th St
Lomita, CA 90717
Meter Site Document
Manhole Before Install
Installed
Upstream Pipe Size
Site
Installation Process
Upstream
Temporary Flow Study
PSOMAS
2023.11 248th St MH
Utility Systems, Science and Software
Santa Ana, CA 92705
601 N. Parkcenter Dr, Suite 209
Meter Start Date From 11/6/2023
Meter Stop Date To 11/22/2023
Velocity (fps) Level (in) Flow (mgd)
Average 1.004 2.878 0.100
Maximum 1.340 3.860 0.174
Minimum 0.460 1.580 0.019
Pipe Size 12.000
Estimated Capacity (mgd) Not Calculated
Capacity Used Not Calculated
Sensor Type Hach - Flodar
El Cajon, CA 92020
1300 Hill St
2023.11 252nd St MH
MH at ~ 1760 252nd St
MH in center of road north of address X
Install Date: 11/06/2023
Access: System Type:

Sanitary Storm
Map
Sewer Map
Flow Meter
Meter Depth: 100.37"
MH Coordinates: 33.795795, -118.309550
Moderate open channel hydraulics with little
turbulence due to inflow from laterals
Avg Velocity Avg Measured Level Multiplier

3.6 fps 2.7" 1.0
Gas
O2 H2S CO LEL

20.9 0 0 0
Notes
Pipes entering from the east, west and south;
monitored the downstream to get total flow.

Traffic Safety
Used cones & signs in accord w/site-specific
CATTCH requirements.

Land Use
Residential Commercial Industrial Trunk
X
North
Manhole Depth
10"
118"
Round
10"/10"
Good
Brick
None observed
Passed

0.4 2-D

17.63"

7.63"
Downstream
Flow Heading
Sensor Direction
Sensor Dist. to Crown
Sensor Offset
Velocity Profile Data
Velocity Profile Taken
Silt
Manhole Material
Pipe Condition
Pipe Shape
Inner Pipe Size (In/Out)
Monitored Pipe Size
PSOMAS
Lomita, CA 90717
MH # unknown
Site Report
Confidential Proprietary Information
11/28/2023
2023.11 252nd St MH
MH at ~ 1760 252nd St
Lomita, CA 90717
Meter Site Document
Manhole Before Install
Installed
Downstream Pipe Size
Site
Installation Process
Downstream
Temporary Flow Study
PSOMAS
2023.11 252nd St MH
Utility Systems, Science and Software
Santa Ana, CA 92705
601 N. Parkcenter Dr, Suite 209
Meter Start Date From 11/6/2023
Meter Stop Date To 11/22/2023
Velocity (fps) Level (in) Flow (mgd)
Average 3.612 2.752 0.297
Maximum 4.520 3.690 0.533
Minimum 2.110 1.800 0.100
Pipe Size 10.000
Estimated Capacity (mgd) Not Calculated
Capacity Used Not Calculated
Sensor Type Hach - Flodar
El Cajon, CA 92020
1300 Hill St
Velocity (fps) Level (in) Flow (gpm)
Average 1.872 3.004 153.717 RainFall Inches
Maximum 2.390 4.070 269.749
Minimum 1.030 1.890 42.911 11/28/2023
Velocity (fps) Level (in) Flow (gpm)
Average 1.852 2.938 147.972 RainFall Inches
Maximum 2.390 4.070 265.188
Minimum 1.030 1.800 38.600 11/28/2023
Velocity (fps) Level (in) Flow (gpm)
Average 1.856 2.832 138.990 RainFall Inches
Maximum 2.270 3.540 225.417
Minimum 1.100 1.980 53.843 11/28/2023
11/28/2023 2:12:32 PM
11/6/2023 thru 11/22/2023
2023.11 250th St MH:
11/06/2023 thru 11/22/2023
Report Date: 11/28/2023
Customer: PSOMAS
Group: Lomita FM Project
Site: 2023.11 250th St MH
Velocity (fps) Level (in) Flow (gpm)
Average 1.027 2.878 71.313 RainFall Inches
Maximum 1.340 3.860 121.129
Minimum 0.560 1.580 15.753 11/28/2023
Velocity (fps) Level (in) Flow (gpm)
Average 0.993 2.862 68.624 RainFall Inches
Maximum 1.330 3.680 116.868
Minimum 0.520 1.640 15.552 11/28/2023
Velocity (fps) Level (in) Flow (gpm)
Average 0.970 2.854 66.927 RainFall Inches
Maximum 1.270 3.650 113.711
Minimum 0.460 1.610 12.848 11/28/2023
11/28/2023 2:35:57 PM
11/6/2023 thru 11/22/2023
2023.11 248th St MH:
11/06/2023 thru 11/22/2023
Report Date: 11/28/2023
Customer: PSOMAS
Group: Lomita FM Project
Site: 2023.11 248th St MH
Velocity (fps) Level (in) Flow (gpm)
Average 3.652 2.748 207.298 RainFall Inches
Maximum 4.500 3.570 339.376
Minimum 2.360 1.930 84.073 11/28/2023
Velocity (fps) Level (in) Flow (gpm)
Average 3.598 2.755 205.831 RainFall Inches
Maximum 4.520 3.690 370.008
Minimum 2.110 1.910 69.771 11/28/2023
Velocity (fps) Level (in) Flow (gpm)
Average 3.519 2.706 197.391 RainFall Inches
Maximum 4.310 3.590 337.344
Minimum 2.150 1.800 69.163 11/28/2023
11/28/2023 2:26:25 PM
11/6/2023 thru 11/22/2023
2023.11 252nd St MH:
11/06/2023 thru 11/22/2023
Report Date: 11/28/2023
Customer: PSOMAS
Group: Lomita FM Project
Site: 2023.11 252nd St MH

APPENDIX D

MODLE CALIBRATION AND PEAKING
Flow Montiroing Basin #1 Average Flow Calibration
Row Labels AREA (SF) UNITS FACTOR GPD GPM
Commercial 678,108 38 24,562 17.1
Auto, Recreation EQPT, Construction EQPT, Sales & Service 31,968 0 1000 734 0.51 Banks Savings & Loan 30,441 1 1500 1,048 0.73
Commercial 67,239 0 1500 2,315 1.61
Hotel & Motels 30,437 19 1500 1,048 0.73
Office Buildings 10,228 0 1500 352 0.24
Parking Lots (Commercial Use Properties) 4,772 0 0 - 0.00 Professional Buildings 31,072 0 1500 1,070 0.74
Restaurants, Cocktail Lounges 40,822 2 1700 1,593 1.11
Service Stations 58,318 1 1000 1,339 0.93
Shopping 24,350 0 1500 838 0.58
Store Combination 104,029 11 1500 3,582 2.49
Stores 195,779 4 1500 6,742 4.68
Government 48,653 0 800 894 0.62
Industrial 32,772 0 - 0.00
Warehousing, Distribution, Storage 32,772 0 500 376 0.26 Institutional 104,664 2 - 0.00
Churches 52,403 0 800 962 0.67
Schools (Private) 52,261 2 800 960 0.67
Miscellaneous 61,658 1 - 0.00
Petroleum & Gas 4,017 0 500 46 0.03
Utility Commercial & Mutual: Pumping Plants State Assessed Pr 57,640 1 500 662 0.46 Residential 7,705,397 1608 450 226,340 157.2
Five or more apartments 2,429,369 503 100 50,300 34.93
Four Units (Any Combination) 323,636 87 100 8,700 6.04
Mobile Home Parks 230,093 203 100 20,300 14.10
Senior Home 0 47 90 4,230 2.94
Single 2,683,448 497 210 104,370 72.48
Three Units (Any Combination) 538,092 114 110 12,540 8.71 Two Units 503,804 101 140 14,140 9.82
LDR 996,955 56 210 11,760 8.17
Grand Total 8,582,599 1649 250,902 174
Basin #1 FM AVG 149
Flow Montiroing Basin #2 Average Flow Calibration
Row Labels AREA (SF) UNITS FACTOR GPD GPM
Commercial 765,664 47 37,969 26.4
Auto, Recreation EQPT, Construction EQPT, Sales & Service 75,746 1 1000 1,739 1.21 Commercial 38,033 1 1500 1,310 0.91
Office Buildings 54,333 13 1500 1,871 1.30
Parking Lots (Commercial Use Properties) 27,635 1 0 - 0.00 Restaurants, Cocktail Lounges 121,490 2 1700 4,741 3.29 Service Stations 23,027 0 1000 529 0.37
Shopping Centers (Neighborhood, community) 231,948 0 1700 9,052 6.29 Store Combination 37,449 12 1500 1,290 0.90
Stores 156,002 17 1500 5,372 3.73
Government 202,362 1
Government Parcel 202,362 1 1500 6,968 4.84
Industrial 12,746 0
Lumber Yards 12,746 0 800 234 0.16
Institutional 161,126 6
Churches 106,281 5 800 1,952 1.36
Homes For Aged & Others 54,845 1 1500 1,889 1.31
Miscellaneous 51,946 1
Utility Commercial & Mutual: Pumping Plants State Assessed Pr 51,946 1 500 596 0.41 Recreational 12,394 2
Athletic & Amusement Facilities 12,394 2 1500 427 0.30
Residential 14,411,720 1688 156 263,240 182.8
Five or more apartments 1,373,461 542 100 54,200 37.64
Four Units (Any Combination) 73,324 27 100 2,700 1.88
Mobile Home Parks 75,360 41 100 4,100 2.85
Multi-Family 6,681,605 66 160 10,560 7.33
Single 1,861,563 339 210 71,190 49.44
Three Units (Any Combination) 241,229 81 110 8,910 6.19 Two Units 626,966 182 140 25,480 17.69
LDR 3,478,212 410 210 86,100 59.79
Grand Total 15,617,957 1745 301,209 209
Basin #2 FM AVG 203
Flow Montiroing Basin #3 Average Flow Calibration
Land Use AREA (SF) UNITS FACTOR GPD GPM
Commercial 304,134 21 15,363 10.7
Auto, Recreation EQPT, Construction EQPT, Sales & Service 51,500 3 1000 1,182 0.82 Commercial 47,663 0 1500 1,641 1.14
Office Buildings 26,394 2 1500 909 0.63
Professional Buildings 24,441 0 1500 842 0.58
Restaurants, Cocktail Lounges 8,191 2 1700 320 0.22
Service Stations 22,395 0 1000 514 0.36
Srvc Shps:Radio, TV, Refrig, Pnt Shp 15,076 2 1000 346 0.24 Store Combination 55,590 6 1500 1,914 1.33
Stores 52,883 6 1500 1,821 1.26
Government 193,128 0
Government Parcel 193,128 0 800 3,547 2.46
Industrial 35,048 1
Food Processing Plants 13,713 0 1500 472 0.33
Lgt Manf.Sm. EQPT. Manuf Sm.Shps Instr.Manuf. Prnt Plnts 21,336 1 1500 735 0.51 Institutional 56,284 0
Churches 36,753 0 800 675 0.47
Open 19,531 0 0 - -
Recreational 12,917 1
Clubs., Lodge Halls, Fraternal Organizations 12,917 1 1500 445 0.31 Residential 3,009,547 663 141 93,730 65.09
Five or more apartments 131,467 73 100 7,300 5.07
Four Units (Any Combination) 173,130 80 100 8,000 5.56
Mobile Home Parks 170,547 72 100 7,200 5.00
Multi-Family 544,891 19 160 3,040 2.11
Rooming Houses 7,102 1 100 100 0.07
Single 1,305,688 205 210 43,050 29.90
Three Units (Any Combination) 123,781 52 110 5,720 3.97 Two Units 552,942 161 120 19,320 13.42
Grand Total 3,611,059 686 109,093 76
Basin #3 FM AVG 69

RES CII
1 0.30 0.60
2 0.30 0.30
3 0.20 0.30
4 0.30 0.30
5 0.40 0.35
6 0.50 0.50
7 0.70 0.60
8 0.90 1.00
9 1.60 1.30
10 1.80 1.70
11 1.60 1.50
12 1.30 1.60
13 1.20 1.70
14 1.20 1.60
15 1.10 1.40
16 1.00 1.30
17 1.10 1.20
18 1.20 1.00
19 1.50 0.90
20 1.70 0.90
21 1.60 1.10
22 1.10 1.00
23 0.80 1.00
24 0.60 0.90
AVG 1.00 1.00
HOUR

PEAK FACTOR

0.00 0.20

0.40 0.60

0.80 1.00

1.20 1.40

1.60 1.80

2.00 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

PEAK FACTOR
HOUR
Model Peaking

RES CII
Day Avg (gpm) Max (gpm) Factor
7-Nov 151.1 246.7 1.63
8-Nov 147.4 230.8 1.57
9-Nov 140.8 215.4 1.53
10-Nov 153.5 255.2 1.66
11-Nov 144.2 248.5 1.72
12-Nov 147.4 230.0 1.56
13-Nov 124.7 197.4 1.58
14-Nov 130.6 212.9 1.63
15-Nov 137.1 265.2 1.93
16-Nov 176.7 259.9 1.47
17-Nov 175.4 256.1 1.46
18-Nov 149.1 233.7 1.57
19-Nov 149.2 225.4 1.51
20-Nov 136.8 199.3 1.46
21-Nov 136.4 191.4 1.40
Avg 146.7 265.2 1.81
Avg Week 148.2 265.2 1.79
Avg Weekend 142.6 233.7 1.64
FM SITE 1 SUMMARY
0 50
100
150
200
250
300
350
400
450
11/7/2023 0:00 11/9/2023 0:00 11/11/2023 0:00 11/13/2023 0:00 11/15/2023 0:00 11/17/2023 0:00 11/19/2023 0:00 11/21/2023 0:00 Flow (gpm) FM Site 1 - 250th Street
Observed Flow Modeled Flow - Calibration
Day Avg (gpm) Max (gpm) Factor
7-Nov 207.0 305.1 1.47
8-Nov 214.4 318.8 1.49
9-Nov 191.8 293.3 1.53
10-Nov 200.2 326.0 1.63
11-Nov 214.0 339.4 1.59
12-Nov 218.4 370.0 1.69
13-Nov 206.2 305.0 1.48
14-Nov 203.6 334.5 1.64
15-Nov 206.5 321.1 1.55
16-Nov 202.7 293.0 1.45
17-Nov 195.0 301.1 1.54
18-Nov 205.5 322.2 1.57
19-Nov 208.3 337.3 1.62
20-Nov 199.5 316.4 1.59
21-Nov 197.1 316.4 1.61
Avg 204.7 370.0 1.81
Avg Week 202.9 339.4 1.67
Avg Weekend 209.6 370.0 1.77
FM SITE 2 SUMMARY
0 50
100
150
200
250
300
350
400
450
11/7/2023 0:00 11/9/2023 0:00 11/11/2023 0:00 11/13/2023 0:00 11/15/2023 0:00 11/17/2023 0:00 11/19/2023 0:00 11/21/2023 0:00 Flow (gpm) FM Site 2 - 252nd Street
Observed Flow Modeled Flow - Calibration
Day Avg (gpm) Max (gpm) Factor
7-Jan 76.1 118.8 1.56
8-Jan 68.5 105.4 1.54
9-Jan 68.7 105.7 1.54
10-Jan 71.6 121.1 1.69
11-Jan 65.4 110.7 1.69
12-Jan 69.1 116.9 1.69
13-Jan 67.9 98.9 1.46
14-Jan 68.5 104.8 1.53
15-Jan 69.2 111.0 1.61
16-Jan 69.8 111.5 1.60
17-Jan 68.4 103.1 1.51
18-Jan 69.0 108.5 1.57
19-Jan 67.6 113.7 1.68
20-Jan 70.1 107.8 1.54
21-Jan 67.2 108.8 1.62
Avg 69.1 121.1 1.75
Avg Week 69.4 121.1 1.75
Avg Weekend 68.4 116.9 1.71
FM SITE 3 SUMMARY
0 20
40 60
80 100
120
140
160
180
200
11/7/2023 0:00 11/9/2023 0:00 11/11/2023 0:00 11/13/2023 0:00 11/15/2023 0:00 11/17/2023 0:00 11/19/2023 0:00 11/21/2023 0:00 Flow (gpm) FM Site 3 - 248th Street
Observed Flow Modeled Flow - Calibration

APPENDIX E

MODLE OUTPUT DATA

EXISTING SCENARIO MODEL OUTPUT
Street
Name From MH To MH
Diam.
(in)
Length
(ft) Slope
Existing
Flow
(gpm)
d/D
Ratio
Analysis
Flow
(gpm)
Analysis
Excess
(gpm)
Analysis
d/D
Ratio
Design
Flow
(gpm)
Design
Excess
(gpm)
Design
d/D
Ratio
SFR DUs
Limit
Appt.

Units
Limit
1652-0552 1652-0553 8 264.3 0.0800 109.3 0.19 1,055.4 946.066 0.67 668.5 559.2 0.5 3,604 7,569 1652-0593 1652-0544 8 188.5 0.0230 90.7 0.24 561.1 470.445 0.67 355.5 264.8 0.5 1,792 3,764 1652-0544 1652-0546 8 68.8 0.0010 90.7 0.50 141.9 51.207 0.67 89.9 -0.8 0.5 195 410 1652-0546 1652-0552 8 245.0 0.0200 94.9 0.26 525.5 430.64 0.67 332.9 238.0 0.5 1,641 3,445 1652-0553 1652-0556 8 263.0 0.0150 109.3 0.30 450.1 340.768 0.67 285.1 175.8 0.5 1,298 2,726 1652-0556 1652-0558 8 285.8 0.0130 121.4 0.32 431.8 310.417 0.67 273.5 152.1 0.5 1,183 2,483 1652-0558 1652-0557 8 239.0 0.0160 121.4 0.31 475.2 353.823 0.67 301.0 179.6 0.5 1,348 2,831 1652-0557 1652-0565 10 269.0 0.0120 140.3 0.26 739.1 598.739 0.67 468.2 327.8 0.5 2,281 4,790 1652-0565 1652-0567 10 175.3 0.0180 140.3 0.24 914.2 773.922 0.67 579.1 438.8 0.5 2,948 6,191 1652-0567 1652-0575 10 87.5 0.0010 144.2 0.50 228.0 83.834 0.67 144.4 0.3 0.5 319 671 1652-0575 1652-0576 10 262.8 0.0130 153.8 0.27 770.6 616.78 0.67 488.2 334.3 0.5 2,350 4,934 1652-0576 1652-0620 10 51.5 0.0020 153.8 0.45 297.2 143.36 0.67 188.3 34.4 0.5 546 1,147 1652-0620 1652-0582 10 209.3 0.0170 158.5 0.26 868.5 709.98 0.67 550.2 391.6 0.5 2,705 5,680 1652-0582 1652-0583 10 268.6 0.0100 173.9 0.31 659.8 485.919 0.67 418.0 244.1 0.5 1,851 3,887 1652-0583 1652-0584 10 244.9 0.0110 173.9 0.30 699.0 525.13 0.67 442.8 268.9 0.5 2,000 4,201 1652-0584 1652-0628 12 275.4 0.0060 182.3 0.28 1,004.2 821.899 0.75 739.9 557.6 0.6 3,131 6,575 1652-0628 1652-0629 12 275.0 0.0060 190.2 0.28 1,005.0 814.802 0.75 740.5 550.2 0.6 3,104 6,518 1652-0629 1652-0630 12 275.0 0.0060 190.2 0.28 1,005.0 814.81 0.75 740.5 550.3 0.6 3,104 6,518 1652-0630 1652-0631 15 203.3 0.0040 308.9 0.30 1,458.9 1,150.06 0.75 1074.9 766.0 0.6 4,381 9,200 1652-0631 1652-0632 15 209.5 0.0040 309.1 0.30 1,454.9 1,145.79 0.75 1071.9 762.8 0.6 4,365 9,166 1652-0632 1652-0633 12 193.0 0.0030 330.2 0.45 712.4 382.187 0.75 524.8 194.7 0.6 1,456 3,057 1652-0633 1652-0634 15 54.5 0.0030 330.2 0.34 1,244.8 914.585 0.75 917.1 586.9 0.6 3,484 7,317 1652-0634 SD1838 15 139.3 0.0060 332.7 0.28 1,719.4 1,386.71 0.75 1266.8 934.1 0.6 5,283 11,094 1652-0490 1652-0485 8 293.8 0.0120 59.1 0.23 402.0 342.847 0.67 254.6 195.5 0.5 1,306 2,743 1652-0485 1652-0484 8 202.5 0.0150 61.0 0.22 452.0 390.997 0.67 286.3 225.3 0.5 1,490 3,128 1652-0484 1652-0483 8 116.5 0.0140 66.9 0.24 433.2 366.292 0.67 274.4 207.5 0.5 1,395 2,930 1652-0483 1652-0482 8 198.3 0.0230 71.4 0.21 567.9 496.446 0.67 359.7 288.3 0.5 1,891 3,972 1652-0482 1652-0481 8 221.3 0.0210 71.4 0.22 533.5 462.036 0.67 337.9 266.5 0.5 1,760 3,696 1652-0481 1652-0476 8 261.5 0.0200 82.0 0.24 523.0 441.042 0.67 331.3 249.3 0.5 1,680 3,528 1652-0476 1652-0475 8 47.5 0.0020 82.0 0.43 170.7 88.683 0.67 108.1 26.1 0.5 338 709 1652-0475 1652-0472 8 204.1 0.0260 86.9 0.23 595.4 508.559 0.67 377.2 290.3 0.5 1,937 4,068 1652-0472 1652-0469 8 323.1 0.0200 94.8 0.26 523.9 429.18 0.67 331.9 237.1 0.5 1,635 3,433 Pennsylvania Ave 250th Street Cypress St

Page 1 ends

Units
Limit
1652-0469 1652-0468 8 309.3 0.0200 100.2 0.26 527.5 427.333 0.67 334.2 234.0 0.5 1,628 3,419 1652-0468 1652-0467 8 338.5 0.0040 105.7 0.42 223.3 117.605 0.67 141.5 35.7 0.5 448 941 1652-0467 1652-0612 10 203.4 0.0120 109.4 0.23 747.7 638.272 0.67 473.6 364.2 0.5 2,432 5,106 1652-0612 1652-0466 10 100.2 0.0010 113.9 0.45 213.1 99.228 0.67 135.0 21.1 0.5 378 794 1652-0466 1652-0630 10 299.2 0.0080 117.2 0.26 615.3 498.08 0.67 389.8 272.6 0.5 1,897 3,985 1652-0383 1652-0386 8 309.1 0.0160 75.3 0.24 467.4 392.102 0.67 296.1 220.8 0.5 1,494 3,137 1652-0386 1652-0388 8 135.8 0.0010 78.0 0.56 100.9 22.981 0.67 63.9 -14.0 0.5 88 184 1652-0388 1652-0393 8 160.5 0.0300 80.4 0.21 648.6 568.282 0.67 410.9 330.5 0.5 2,165 4,546 1652-0393 1652-0394 8 218.8 0.0140 90.7 0.27 446.3 355.669 0.67 282.7 192.1 0.5 1,355 2,845 1652-0394 1652-0399 8 210.3 0.0290 91.4 0.23 636.7 545.291 0.67 403.3 311.9 0.5 2,077 4,362 1652-0399 1652-0400 8 326.5 0.0150 102.7 0.29 448.7 345.963 0.67 284.2 181.5 0.5 1,318 2,768 1652-0400 1652-0406 8 350.0 0.0170 110.5 0.29 491.5 381.041 0.67 311.3 200.9 0.5 1,452 3,048 1652-0406 1652-0407 8 342.8 0.0160 123.9 0.31 477.2 353.269 0.67 302.3 178.4 0.5 1,346 2,826 1652-0407 1652-0409 8 301.7 0.0140 130.2 0.33 440.5 310.276 0.67 279.0 148.8 0.5 1,182 2,482 1652-0409 1652-0410 8 75.0 0.0810 132.2 0.21 1,055.6 923.412 0.67 668.7 536.5 0.5 3,518 7,387 1652-0410 1652-0411 8 398.1 0.0140 142.0 0.34 445.1 303.128 0.67 282.0 140.0 0.5 1,155 2,425 1652-0411 SD1833 8 295.7 0.0150 144.6 0.34 452.3 307.718 0.67 286.5 141.9 0.5 1,172 2,462 1652-0335 1652-0330 8 356.6 0.0190 46.1 0.18 509.5 463.455 0.67 322.8 276.7 0.5 1,766 3,708 1652-0330 1652-0329 8 331.8 0.0200 48.8 0.18 531.0 482.211 0.67 336.4 287.6 0.5 1,837 3,858 1652-0329 1652-0328 8 346.1 0.0190 52.1 0.19 509.4 457.307 0.67 322.7 270.6 0.5 1,742 3,658 1652-0328 1652-0324 8 356.9 0.0190 61.5 0.21 509.3 447.756 0.67 322.6 261.1 0.5 1,706 3,582 1652-0324 1652-0323 8 302.9 0.0170 61.5 0.21 485.1 423.561 0.67 307.3 245.8 0.5 1,614 3,388 1652-0323 1652-0318 8 55.3 0.0020 71.8 0.41 158.2 86.388 0.67 100.2 28.4 0.5 329 691 1652-0318 1652-0317 8 349.7 0.0150 71.8 0.24 451.5 379.71 0.67 286.0 214.2 0.5 1,447 3,038 1652-0317 1652-0316 8 271.8 0.0190 73.3 0.23 511.5 438.223 0.67 324.0 250.7 0.5 1,669 3,506 1652-0316 1652-0315 8 241.3 0.0140 75.6 0.25 446.7 371.151 0.67 283.0 207.4 0.5 1,414 2,969 1652-0315 SD1828 8 238.2 0.0130 75.6 0.25 421.6 346.049 0.67 267.1 191.5 0.5 1,318 2,768 Oak St Eshelman Ave Cypress St

Page 2 ends

Units
Limit
1652-0174 1652-0184 10 336.8 0.0060 313.5 0.50 503.9 190.43 0.67 319.2 5.7 0.5 725 1,523 1652-0184 1652-0185 10 189.1 0.0120 327.4 0.41 745.6 418.128 0.67 472.3 144.8 0.5 1,593 3,345 1652-0185 1652-0189 10 179.1 0.0130 327.4 0.40 780.8 453.344 0.67 494.6 167.2 0.5 1,727 3,627 1652-0189 1652-0190 10 182.5 0.0060 337.6 0.51 521.3 183.676 0.67 330.2 -7.4 0.5 700 1,469 1652-0190 1652-0192 10 176.2 0.0060 337.6 0.50 533.0 195.36 0.67 337.6 0.0 0.5 744 1,563 1652-0192 1652-0193 10 142.9 0.0070 344.4 0.50 544.2 199.789 0.67 344.7 0.3 0.5 761 1,598 1652-0193 1652-0194 10 36.2 0.0120 344.4 0.42 734.7 390.231 0.67 465.4 120.9 0.5 1,487 3,122 1652-0194 1652-0201 10 177.3 0.0060 344.4 0.52 506.6 162.213 0.67 320.9 -23.5 0.5 618 1,298 1652-0201 1652-0202 10 240.6 0.0160 353.7 0.39 858.7 504.961 0.67 544.0 190.2 0.5 1,924 4,040 1652-0202 1652-0204 10 65.2 0.0170 353.7 0.39 880.4 526.725 0.67 557.7 204.0 0.5 2,007 4,214 1652-0204 1652-0617 10 70.8 0.0170 355.8 0.39 877.9 522.102 0.67 556.1 200.3 0.5 1,989 4,177 1652-0617 1652-0616 10 40.9 0.0170 355.8 0.39 881.9 526.168 0.67 558.7 202.9 0.5 2,004 4,209 1652-0616 1652-0208 10 182.0 0.0170 357.5 0.39 878.8 521.259 0.67 556.7 199.1 0.5 1,986 4,170 1652-0208 1652-0211 10 264.8 0.0120 366.3 0.44 726.2 359.975 0.67 460.0 93.8 0.5 1,371 2,880 1652-0211 1652-0212 10 198.2 0.0090 372.2 0.48 624.7 252.537 0.67 395.7 23.6 0.5 962 2,020 1652-0212 1652-0217 10 305.6 0.0060 373.5 0.54 516.2 142.722 0.67 327.0 -46.5 0.5 544 1,142 1652-0224 1652-0223 8 286.1 0.0180 49.1 0.19 493.8 444.7 0.67 312.8 263.7 0.5 1,694 3,558 1652-0223 1652-0624 8 63.6 0.0020 49.0 0.35 147.5 98.462 0.67 93.4 44.4 0.5 375 788 1652-0624 1652-0222 8 104.2 0.0250 49.0 0.17 591.1 542.114 0.67 374.5 325.4 0.5 2,065 4,337 1652-0222 1652-0221 8 129.7 0.0200 49.0 0.18 529.7 480.738 0.67 335.6 286.6 0.5 1,831 3,846 1652-0221 1652-0220 8 315.8 0.0090 49.0 0.23 347.1 298.142 0.67 219.9 170.9 0.5 1,136 2,385 1652-0220 1652-0219 8 80.5 0.0010 49.5 0.37 131.1 81.633 0.67 83.1 33.6 0.5 311 653 1652-0219 1652-0218 8 281.4 0.0100 50.5 0.22 367.8 317.292 0.67 233.0 182.5 0.5 1,209 2,538 1652-0218 1652-0217 8 342.4 0.0080 51.5 0.24 333.4 281.887 0.67 211.2 159.7 0.5 1,074 2,255 1652-0217 SD1707 12 315.7 0.0050 425.4 0.45 929.9 504.408 0.75 685.1 259.6 0.6 1,922 4,035 Ebony Ln Back Yard Pipeline (PCH to Ebony)

Page 3 ends

Units
Limit
1651-0016 1651-0017 8 319.1 0.0110 42.0 0.20 392.4 350.415 0.67 248.6 206.6 0.5 1,335 2,803 1651-0017 1651-0293 8 367.3 0.0060 47.1 0.24 293.7 246.667 0.67 186.1 139.0 0.5 940 1,973 1651-0071 1651-0073 8 180.1 0.0030 59.1 0.32 209.3 150.115 0.67 132.6 73.4 0.5 572 1,201 1651-0073 1651-0074 8 166.9 0.0030 59.1 0.32 217.4 158.316 0.67 137.7 78.6 0.5 603 1,267 1651-0074 1651-0293 8 37.1 0.0050 63.1 0.29 273.3 210.216 0.67 173.1 110.0 0.5 801 1,682 1651-0293 1651-0018 10 122.8 0.0040 110.0 0.32 403.7 293.717 0.67 255.7 145.7 0.5 1,119 2,350 1651-0018 1651-0019 10 46.5 0.0020 112.4 0.36 328.0 215.566 0.67 207.8 95.3 0.5 821 1,725 1651-0019 1651-0292 12 303.0 0.0020 119.4 0.31 514.7 395.333 0.75 379.2 259.8 0.6 1,506 3,163 1651-0292 1651-0020 12 206.3 0.0020 133.3 0.32 551.0 417.621 0.75 405.9 272.6 0.6 1,591 3,341 1651-0020 1651-0021 12 284.3 0.0010 135.2 0.35 469.3 334.096 0.75 345.8 210.6 0.6 1,273 2,673 1651-0021 1651-0022 12 104.9 0.0030 136.4 0.28 742.4 606.007 0.75 547.0 410.6 0.6 2,309 4,848 1651-0022 1651-0023 12 211.6 0.0020 138.1 0.31 603.4 465.299 0.75 444.6 306.5 0.6 1,773 3,722 1651-0023 1651-0322 12 146.3 0.0160 138.1 0.19 1,622.9 1,484.77 0.75 1195.7 1057.6 0.6 5,656 11,878 1651-0322 1651-0024 12 57.3 0.0420 140.2 0.15 2,592.4 2,452.25 0.75 1910.0 1769.8 0.6 9,342 19,618 1651-0024 1651-0025 12 95.1 0.0140 140.2 0.20 1,481.3 1,341.15 0.75 1091.4 951.2 0.6 5,109 10,729 1651-0025 SD1839 12 272.0 0.0050 142.5 0.26 876.0 733.514 0.75 645.4 502.9 0.6 2,794 5,868 NOTE: The maximum number of new SFR DUs or Appartment Units in the most restrictive segments are highlighted in blue. 248th St

Page 4 ends

BUILDOUT SCENARIO 1 MODEL OUTPUT
Street
Name From MH To MH
Diam.
(in)
Length
(ft) Slope
Existing
Flow
(gpm) d/D Ratio
Analysis
Flow
(gpm)
Analysis
Excess
(gpm)
Analysis
d/D Ratio
Design
Flow
(gpm)
Design
Excess
(gpm)
Design
d/D Ratio
1652-0552 1652-0553 8 264.3 0.0800 121.7 0.20 1,055.4 933.7 0.67 668.5 546.8 0.5 1652-0593 1652-0544 8 188.5 0.0230 99.8 0.25 561.1 461.3 0.67 355.5 255.6 0.5 1652-0544 1652-0546 8 68.8 0.0010 99.8 0.53 141.9 42.1 0.67 89.9 -9.9 0.5 1652-0546 1652-0552 8 245.0 0.0200 107.9 0.27 525.5 417.7 0.67 332.9 225.1 0.5 1652-0553 1652-0556 8 263.0 0.0150 121.7 0.31 450.1 328.4 0.67 285.1 163.4 0.5 1652-0556 1652-0558 8 285.8 0.0130 134.2 0.34 431.8 297.6 0.67 273.5 139.3 0.5 1652-0558 1652-0557 8 239.0 0.0160 134.2 0.32 475.2 341.0 0.67 301.0 166.8 0.5 1652-0557 1652-0565 10 269.0 0.0120 153.7 0.27 739.1 585.3 0.67 468.2 314.4 0.5 1652-0565 1652-0567 10 175.3 0.0180 153.7 0.25 914.2 760.5 0.67 579.1 425.4 0.5 1652-0567 1652-0575 10 87.5 0.0010 157.8 0.53 228.0 70.2 0.67 144.4 -13.3 0.5 1652-0575 1652-0576 10 262.8 0.0130 167.7 0.28 770.6 602.9 0.67 488.2 320.4 0.5 1652-0576 1652-0620 10 51.5 0.0020 167.7 0.47 297.2 129.5 0.67 188.3 20.5 0.5 1652-0620 1652-0582 10 209.3 0.0170 172.4 0.27 868.5 696.2 0.67 550.2 377.8 0.5 1652-0582 1652-0583 10 268.6 0.0100 188.1 0.32 659.8 471.8 0.67 418.0 229.9 0.5 1652-0583 1652-0584 10 244.9 0.0110 188.1 0.31 699.0 511.0 0.67 442.8 254.8 0.5 1652-0584 1652-0628 12 275.4 0.0060 196.7 0.29 1,004.2 807.5 0.75 739.9 543.2 0.6 1652-0628 1652-0629 12 275.0 0.0060 204.6 0.29 1,005.0 800.4 0.75 740.5 535.9 0.6 1652-0629 1652-0630 12 275.0 0.0060 204.6 0.29 1,005.0 800.4 0.75 740.5 535.9 0.6 1652-0630 1652-0631 15 203.3 0.0040 353.5 0.32 1,458.9 1,105.4 0.75 1074.9 721.4 0.6 1652-0631 1652-0632 15 209.5 0.0040 353.8 0.32 1,454.9 1,101.2 0.75 1071.9 718.2 0.6 1652-0632 1652-0633 12 193.0 0.0030 376.6 0.49 712.4 335.8 0.75 524.8 148.3 0.6 1652-0633 1652-0634 15 54.5 0.0030 376.6 0.36 1,244.8 868.2 0.75 917.1 540.5 0.6 1652-0634 SD1838 15 139.3 0.0060 381.1 0.31 1,719.4 1,338.3 0.75 1266.8 885.7 0.6 1652-0490 1652-0485 8 293.8 0.0120 88.1 0.28 402.0 313.8 0.67 254.6 166.5 0.5 1652-0485 1652-0484 8 202.5 0.0150 90.1 0.27 452.0 361.9 0.67 286.3 196.2 0.5 1652-0484 1652-0483 8 116.5 0.0140 96.2 0.28 433.2 337.0 0.67 274.4 178.2 0.5 1652-0483 1652-0482 8 198.3 0.0230 100.9 0.25 567.9 467.0 0.67 359.7 258.8 0.5 1652-0482 1652-0481 8 221.3 0.0210 100.9 0.26 533.5 432.5 0.67 337.9 237.0 0.5 1652-0481 1652-0476 8 261.5 0.0200 111.6 0.28 523.0 411.4 0.67 331.3 219.7 0.5 1652-0476 1652-0475 8 47.5 0.0020 111.6 0.51 170.7 59.1 0.67 108.1 -3.5 0.5 Cypress St Pennsylvania Ave 250th Street

Page 1 of 4 ends

BUILDOUT SCENARIO 1 MODEL OUTPUT
Street
Name From MH To MH
Diam.
(in)
Length
(ft) Slope
Existing
Flow
(gpm) d/D Ratio
Analysis
Flow
(gpm)
Analysis
Excess
(gpm)
Analysis
d/D Ratio
Design
Flow
(gpm)
Design
Excess
(gpm)
Design
d/D Ratio
1652-0475 1652-0472 8 204.1 0.0260 116.6 0.27 595.4 478.8 0.67 377.2 260.6 0.5 1652-0472 1652-0469 8 323.1 0.0200 124.7 0.29 523.9 399.2 0.67 331.9 207.2 0.5 1652-0469 1652-0468 8 309.3 0.0200 130.2 0.30 527.5 397.3 0.67 334.2 203.9 0.5 1652-0468 1652-0467 8 338.5 0.0040 135.7 0.49 223.3 87.6 0.67 141.5 5.7 0.5 1652-0467 1652-0612 10 203.4 0.0120 139.6 0.26 747.7 608.1 0.67 473.6 334.0 0.5 1652-0612 1652-0466 10 100.2 0.0010 144.2 0.52 213.1 68.9 0.67 135.0 -9.2 0.5 1652-0466 1652-0630 10 299.2 0.0080 147.4 0.30 615.3 467.9 0.67 389.8 242.4 0.5 1652-0383 1652-0386 8 309.1 0.0160 128.4 0.32 467.4 339.0 0.67 296.1 167.7 0.5 1652-0386 1652-0388 8 135.8 0.0010 133.5 1.00 100.9 -32.6 0.67 63.9 -69.6 0.5 1652-0388 1652-0393 8 160.5 0.0300 135.9 0.28 648.6 512.8 0.67 410.9 275.0 0.5 1652-0393 1652-0394 8 218.8 0.0140 149.7 0.35 446.3 296.6 0.67 282.7 133.0 0.5 1652-0394 1652-0399 8 210.3 0.0290 150.5 0.29 636.7 486.2 0.67 403.3 252.8 0.5 1652-0399 1652-0400 8 326.5 0.0150 163.4 0.37 448.7 285.3 0.67 284.2 120.9 0.5 1652-0400 1652-0406 8 350.0 0.0170 171.1 0.36 491.5 320.4 0.67 311.3 140.2 0.5 1652-0406 1652-0407 8 342.8 0.0160 185.5 0.38 477.2 291.7 0.67 302.3 116.8 0.5 1652-0407 1652-0409 8 301.7 0.0140 191.8 0.40 440.5 248.6 0.67 279.0 87.2 0.5 1652-0409 1652-0410 8 75.0 0.0810 193.9 0.26 1,055.6 861.8 0.67 668.7 474.8 0.5 1652-0410 1652-0411 8 398.1 0.0140 203.7 0.42 445.1 241.5 0.67 282.0 78.3 0.5 1652-0411 SD1833 8 295.7 0.0150 206.3 0.42 452.3 245.9 0.67 286.5 80.2 0.5 1652-0335 1652-0330 8 356.6 0.0190 73.1 0.23 509.5 436.4 0.67 322.8 249.7 0.5 1652-0330 1652-0329 8 331.8 0.0200 75.9 0.23 531.0 455.1 0.67 336.4 260.5 0.5 1652-0329 1652-0328 8 346.1 0.0190 79.2 0.24 509.4 430.2 0.67 322.7 243.5 0.5 1652-0328 1652-0324 8 356.9 0.0190 88.7 0.25 509.3 420.6 0.67 322.6 233.9 0.5 1652-0324 1652-0323 8 302.9 0.0170 88.7 0.26 485.1 396.4 0.67 307.3 218.6 0.5 1652-0323 1652-0318 8 55.3 0.0020 99.3 0.50 158.2 58.8 0.67 100.2 0.9 0.5 1652-0318 1652-0317 8 349.7 0.0150 99.3 0.28 451.5 352.2 0.67 286.0 186.7 0.5 1652-0317 1652-0316 8 271.8 0.0190 100.9 0.27 511.5 410.6 0.67 324.0 223.1 0.5 1652-0316 1652-0315 8 241.3 0.0140 103.3 0.29 446.7 343.4 0.67 283.0 179.7 0.5 1652-0315 SD1828 8 238.2 0.0130 103.3 0.30 421.6 318.3 0.67 267.1 163.8 0.5 Cypress St Oak St Eshelman Ave

Page 2 of 4 ends

BUILDOUT SCENARIO 1 MODEL OUTPUT
Street
Name From MH To MH
Diam.
(in)
Length
(ft) Slope
Existing
Flow
(gpm) d/D Ratio
Analysis
Flow
(gpm)
Analysis
Excess
(gpm)
Analysis
d/D Ratio
Design
Flow
(gpm)
Design
Excess
(gpm)
Design
d/D Ratio
1652-0174 1652-0184 10 336.8 0.0060 524.0 0.69 503.9 -20.1 0.67 319.2 -204.8 0.5 1652-0184 1652-0185 10 189.1 0.0120 536.7 0.54 745.6 208.8 0.67 472.3 -64.4 0.5 1652-0185 1652-0189 10 179.1 0.0130 536.7 0.53 780.8 244.1 0.67 494.6 -42.1 0.5 1652-0189 1652-0190 10 182.5 0.0060 547.0 0.69 521.3 -25.7 0.67 330.2 -216.7 0.5 1652-0190 1652-0192 10 176.2 0.0060 546.9 0.68 533.0 -13.9 0.67 337.6 -209.3 0.5 1652-0192 1652-0193 10 142.9 0.0070 553.7 0.68 544.2 -9.5 0.67 344.7 -209.0 0.5 1652-0193 1652-0194 10 36.2 0.0120 553.7 0.56 734.7 181.0 0.67 465.4 -88.3 0.5 1652-0194 1652-0201 10 177.3 0.0060 553.7 0.72 506.6 -47.1 0.67 320.9 -232.8 0.5 1652-0201 1652-0202 10 240.6 0.0160 563.2 0.51 858.7 295.5 0.67 544.0 -19.2 0.5 1652-0202 1652-0204 10 65.2 0.0170 563.0 0.50 880.4 317.4 0.67 557.7 -5.3 0.5 1652-0204 1652-0617 10 70.8 0.0170 565.3 0.51 877.9 312.6 0.67 556.1 -9.2 0.5 1652-0617 1652-0616 10 40.9 0.0170 565.2 0.50 881.9 316.7 0.67 558.7 -6.6 0.5 1652-0616 1652-0208 10 182.0 0.0170 567.1 0.51 878.8 311.7 0.67 556.7 -10.4 0.5 1652-0208 1652-0211 10 264.8 0.0120 576.1 0.57 726.2 150.1 0.67 460.0 -116.1 0.5 1652-0211 1652-0212 10 198.2 0.0090 582.0 0.64 624.7 42.7 0.67 395.7 -186.3 0.5 1652-0212 1652-0217 10 305.6 0.0060 583.4 0.74 516.2 -67.2 0.67 327.0 -256.4 0.5 1652-0224 1652-0223 8 286.1 0.0180 58.4 0.21 493.8 435.4 0.67 312.8 254.4 0.5 1652-0223 1652-0624 8 63.6 0.0020 58.4 0.38 147.5 89.1 0.67 93.4 35.1 0.5 1652-0624 1652-0222 8 104.2 0.0250 58.3 0.19 591.1 532.8 0.67 374.5 316.1 0.5 1652-0222 1652-0221 8 129.7 0.0200 58.3 0.20 529.7 471.4 0.67 335.6 277.3 0.5 1652-0221 1652-0220 8 315.8 0.0090 58.3 0.25 347.1 288.8 0.67 219.9 161.6 0.5 1652-0220 1652-0219 8 80.5 0.0010 58.8 0.41 131.1 72.3 0.67 83.1 24.2 0.5 1652-0219 1652-0218 8 281.4 0.0100 59.9 0.24 367.8 307.9 0.67 233.0 173.1 0.5 1652-0218 1652-0217 8 342.4 0.0080 60.9 0.26 333.4 272.5 0.67 211.2 150.3 0.5 1652-0217 SD1707 12 315.7 0.0050 645.7 0.58 929.9 284.2 0.75 685.1 39.4 0.6 Ebony Ln Back Yard Pipeline (PCH to Ebony)

Page 3 of 4 ends

Red highlight - Pipeline capacity is exceeded. 248th St

Page 4 of 4 ends

BUILDOUT SCENARIO 2 MODEL OUTPUT
Street
Name From MH To MH
Diam.
(in)
Length
(ft) Slope
Existing
Flow
(gpm)
d/D
Ratio
Analysis
Flow
(gpm)
Analysis
Excess
(gpm)
Analysis
d/D Ratio
Design
Flow
(gpm)
Design
Excess
(gpm)
Design
d/D
Ratio
1652-0552 1652-0553 8 264.3 0.0800 122.4 0.20 1,055.4 933.0 0.67 668.5 546.1 0.5 1652-0593 1652-0544 8 188.5 0.0230 100.3 0.25 561.1 460.8 0.67 355.5 255.1 0.5 1652-0544 1652-0546 8 68.8 0.0010 100.3 0.53 141.9 41.6 0.67 89.9 -10.4 0.5 1652-0546 1652-0552 8 245.0 0.0200 108.6 0.27 525.5 417.0 0.67 332.9 224.3 0.5 1652-0553 1652-0556 8 263.0 0.0150 122.4 0.32 450.1 327.7 0.67 285.1 162.7 0.5 1652-0556 1652-0558 8 285.8 0.0130 134.9 0.34 431.8 296.8 0.67 273.5 138.6 0.5 1652-0558 1652-0557 8 239.0 0.0160 134.9 0.32 475.2 340.2 0.67 301.0 166.1 0.5 1652-0557 1652-0565 10 269.0 0.0120 154.5 0.28 739.1 584.6 0.67 468.2 313.7 0.5 1652-0565 1652-0567 10 175.3 0.0180 154.5 0.25 914.2 759.8 0.67 579.1 424.7 0.5 1652-0567 1652-0575 10 87.5 0.0010 158.5 0.53 228.0 69.5 0.67 144.4 -14.1 0.5 1652-0575 1652-0576 10 262.8 0.0130 168.5 0.28 770.6 602.1 0.67 488.2 319.7 0.5 1652-0576 1652-0620 10 51.5 0.0020 168.5 0.47 297.2 128.7 0.67 188.3 19.8 0.5 1652-0620 1652-0582 10 209.3 0.0170 173.1 0.27 868.5 695.4 0.67 550.2 377.1 0.5 1652-0582 1652-0583 10 268.6 0.0100 188.8 0.32 659.8 471.0 0.67 418.0 229.2 0.5 1652-0583 1652-0584 10 244.9 0.0110 188.8 0.31 699.0 510.2 0.67 442.8 254.0 0.5 1652-0584 1652-0628 12 275.4 0.0060 197.5 0.29 1,004.2 806.8 0.75 739.9 542.4 0.6 1652-0628 1652-0629 12 275.0 0.0060 205.4 0.29 1,005.0 799.6 0.75 740.5 535.1 0.6 1652-0629 1652-0630 12 275.0 0.0060 205.4 0.29 1,005.0 799.6 0.75 740.5 535.1 0.6 1652-0630 1652-0631 15 203.3 0.0040 355.6 0.32 1,458.9 1,103.3 0.75 1074.9 719.3 0.6 1652-0631 1652-0632 15 209.5 0.0040 355.8 0.32 1,454.9 1,099.1 0.75 1071.9 716.1 0.6 1652-0632 1652-0633 12 193.0 0.0030 378.7 0.49 712.4 333.7 0.75 524.8 146.1 0.6 1652-0633 1652-0634 15 54.5 0.0030 378.7 0.36 1,244.8 866.1 0.75 917.1 538.4 0.6 1652-0634 SD1838 15 139.3 0.0060 383.4 0.31 1,719.4 1,336.1 0.75 1266.8 883.5 0.6 1652-0490 1652-0485 8 293.8 0.0120 89.4 0.28 402.0 312.6 0.67 254.6 165.3 0.5 1652-0485 1652-0484 8 202.5 0.0150 91.3 0.27 452.0 360.7 0.67 286.3 195.0 0.5 1652-0484 1652-0483 8 116.5 0.0140 97.5 0.29 433.2 335.8 0.67 274.4 177.0 0.5 1652-0483 1652-0482 8 198.3 0.0230 102.1 0.26 567.9 465.7 0.67 359.7 257.6 0.5 1652-0482 1652-0481 8 221.3 0.0210 102.1 0.26 533.5 431.3 0.67 337.9 235.8 0.5 1652-0481 1652-0476 8 261.5 0.0200 112.9 0.28 523.0 410.2 0.67 331.3 218.5 0.5 1652-0476 1652-0475 8 47.5 0.0020 112.9 0.51 170.7 57.8 0.67 108.1 -4.7 0.5 Pennsylvania Ave 250th Street Cypress St

Page 1 of 4 ends

BUILDOUT SCENARIO 2 MODEL OUTPUT
Street
Name From MH To MH
Diam.
(in)
Length
(ft) Slope
Existing
Flow
(gpm)
d/D
Ratio
Analysis
Flow
(gpm)
Analysis
Excess
(gpm)
Analysis
d/D Ratio
Design
Flow
(gpm)
Design
Excess
(gpm)
Design
d/D
Ratio
1652-0475 1652-0472 8 204.1 0.0260 117.9 0.27 595.4 477.6 0.67 377.2 259.3 0.5 1652-0472 1652-0469 8 323.1 0.0200 126.0 0.30 523.9 398.0 0.67 331.9 205.9 0.5 1652-0469 1652-0468 8 309.3 0.0200 131.5 0.30 527.5 396.0 0.67 334.2 202.7 0.5 1652-0468 1652-0467 8 338.5 0.0040 137.0 0.49 223.3 86.3 0.67 141.5 4.5 0.5 1652-0467 1652-0612 10 203.4 0.0120 140.9 0.26 747.7 606.8 0.67 473.6 332.8 0.5 1652-0612 1652-0466 10 100.2 0.0010 145.5 0.52 213.1 67.6 0.67 135.0 -10.5 0.5 1652-0466 1652-0630 10 299.2 0.0080 148.7 0.30 615.3 466.6 0.67 389.8 241.1 0.5 1652-0383 1652-0386 8 309.1 0.0160 151.5 0.35 467.4 316.0 0.67 296.1 144.6 0.5 1652-0386 1652-0388 8 135.8 0.0010 157.2 1.00 100.9 -56.2 0.67 63.9 -93.2 0.5 1652-0388 1652-0393 8 160.5 0.0300 159.5 0.30 648.6 489.1 0.67 410.9 251.4 0.5 1652-0393 1652-0394 8 218.8 0.0140 173.5 0.38 446.3 272.9 0.67 282.7 109.3 0.5 1652-0394 1652-0399 8 210.3 0.0290 174.3 0.32 636.7 462.5 0.67 403.3 229.1 0.5 1652-0399 1652-0400 8 326.5 0.0150 187.2 0.40 448.7 261.5 0.67 284.2 97.0 0.5 1652-0400 1652-0406 8 350.0 0.0170 195.0 0.38 491.5 296.5 0.67 311.3 116.4 0.5 1652-0406 1652-0407 8 342.8 0.0160 209.4 0.41 477.2 267.7 0.67 302.3 92.8 0.5 1652-0407 1652-0409 8 301.7 0.0140 215.8 0.43 440.5 224.7 0.67 279.0 63.2 0.5 1652-0409 1652-0410 8 75.0 0.0810 217.8 0.27 1,055.6 837.8 0.67 668.7 450.9 0.5 1652-0410 1652-0411 8 398.1 0.0140 227.6 0.44 445.1 217.5 0.67 282.0 54.4 0.5 1652-0411 SD1833 8 295.7 0.0150 230.3 0.44 452.3 222.0 0.67 286.5 56.2 0.5 1652-0335 1652-0330 8 356.6 0.0190 74.3 0.23 509.5 435.2 0.67 322.8 248.4 0.5 1652-0330 1652-0329 8 331.8 0.0200 77.1 0.23 531.0 453.9 0.67 336.4 259.3 0.5 1652-0329 1652-0328 8 346.1 0.0190 80.4 0.24 509.4 429.0 0.67 322.7 242.3 0.5 1652-0328 1652-0324 8 356.9 0.0190 89.9 0.25 509.3 419.4 0.67 322.6 232.7 0.5 1652-0324 1652-0323 8 302.9 0.0170 89.9 0.26 485.1 395.2 0.67 307.3 217.4 0.5 1652-0323 1652-0318 8 55.3 0.0020 100.6 0.50 158.2 57.6 0.67 100.2 -0.4 0.5 1652-0318 1652-0317 8 349.7 0.0150 100.6 0.28 451.5 350.9 0.67 286.0 185.4 0.5 1652-0317 1652-0316 8 271.8 0.0190 102.2 0.27 511.5 409.4 0.67 324.0 221.9 0.5 1652-0316 1652-0315 8 241.3 0.0140 104.6 0.29 446.7 342.2 0.67 283.0 178.4 0.5 1652-0315 SD1828 8 238.2 0.0130 104.6 0.30 421.6 317.1 0.67 267.1 162.5 0.5 Oak St Eshelman Ave Cypress St

Page 2 of 4 ends

BUILDOUT SCENARIO 2 MODEL OUTPUT
Street
Name From MH To MH
Diam.
(in)
Length
(ft) Slope
Existing
Flow
(gpm)
d/D
Ratio
Analysis
Flow
(gpm)
Analysis
Excess
(gpm)
Analysis
d/D Ratio
Design
Flow
(gpm)
Design
Excess
(gpm)
Design
d/D
Ratio
1652-0174 1652-0184 10 336.8 0.0060 590.6 0.76 503.9 -86.7 0.67 319.2 -271.4 0.5 1652-0184 1652-0185 10 189.1 0.0120 603.3 0.58 745.6 142.3 0.67 472.3 -131.0 0.5 1652-0185 1652-0189 10 179.1 0.0130 603.3 0.56 780.8 177.5 0.67 494.6 -108.7 0.5 1652-0189 1652-0190 10 182.5 0.0060 613.6 0.76 521.3 -92.2 0.67 330.2 -283.3 0.5 1652-0190 1652-0192 10 176.2 0.0060 613.5 0.75 533.0 -80.5 0.67 337.6 -275.9 0.5 1652-0192 1652-0193 10 142.9 0.0070 620.3 0.74 544.2 -76.1 0.67 344.7 -275.6 0.5 1652-0193 1652-0194 10 36.2 0.0120 620.3 0.60 734.7 114.3 0.67 465.4 -154.9 0.5 1652-0194 1652-0201 10 177.3 0.0060 620.3 0.79 506.6 -113.7 0.67 320.9 -299.3 0.5 1652-0201 1652-0202 10 240.6 0.0160 629.9 0.55 858.7 228.8 0.67 544.0 -85.9 0.5 1652-0202 1652-0204 10 65.2 0.0170 629.8 0.54 880.4 250.6 0.67 557.7 -72.1 0.5 1652-0204 1652-0617 10 70.8 0.0170 631.9 0.54 877.9 246.0 0.67 556.1 -75.8 0.5 1652-0617 1652-0616 10 40.9 0.0170 631.9 0.54 881.9 250.0 0.67 558.7 -73.2 0.5 1652-0616 1652-0208 10 182.0 0.0170 633.7 0.54 878.8 245.1 0.67 556.7 -77.1 0.5 1652-0208 1652-0211 10 264.8 0.0120 642.7 0.62 726.2 83.5 0.67 460.0 -182.7 0.5 1652-0211 1652-0212 10 198.2 0.0090 648.8 0.69 624.7 -24.1 0.67 395.7 -253.0 0.5 1652-0212 1652-0217 10 305.6 0.0060 650.1 0.81 516.2 -133.9 0.67 327.0 -323.1 0.5 1652-0224 1652-0223 8 286.1 0.0180 58.9 0.21 493.8 434.9 0.67 312.8 253.9 0.5 1652-0223 1652-0624 8 63.6 0.0020 58.8 0.39 147.5 88.7 0.67 93.4 34.6 0.5 1652-0624 1652-0222 8 104.2 0.0250 58.8 0.19 591.1 532.3 0.67 374.5 315.7 0.5 1652-0222 1652-0221 8 129.7 0.0200 58.8 0.20 529.7 471.0 0.67 335.6 276.8 0.5 1652-0221 1652-0220 8 315.8 0.0090 58.8 0.25 347.1 288.4 0.67 219.9 161.1 0.5 1652-0220 1652-0219 8 80.5 0.0010 59.3 0.41 131.1 71.8 0.67 83.1 23.8 0.5 1652-0219 1652-0218 8 281.4 0.0100 60.3 0.24 367.8 307.5 0.67 233.0 172.7 0.5 1652-0218 1652-0217 8 342.4 0.0080 61.3 0.26 333.4 272.0 0.67 211.2 149.8 0.5 1652-0217 SD1707 12 315.7 0.0050 713.0 0.62 929.9 216.9 0.75 685.1 -27.9 0.6 Ebony Ln Back Yard Pipeline (PCH to Ebony)

Page 3 of 4 ends

Red highlight - Pipeline capacity is exceeded. 248th St

Page 4 of 4 ends

APPENDIX F

HARBOR HILLS PRIVATE SEWER SYSTEM

TECHNICAL MEMORANDUM

TECHNICAL MEMORANDUM
To: Jenn Howell
From: Kim Alexander
Date: August 8, 2024
Subject: Harbor Hills Private Sewer System
Background
Psomas has been working with the City on the preparation of the City’s Sewer System Master Plan. As part of the master planning process, we have identified buildout capacity constraints along the 10-inch pipeline running through residential back yards between Pacific Coast Highway (PCH) and Ebony (back yard pipeline). In addition to capacity constraints, this pipeline was constructed in the 1930s and has structural damage identified in CCTV review. The alignment through back yards creates maintenance and access issues. A proposed capital improvement project would replace the approximately 2,800 LF of deficient pipeline aligned through back yards with 9,800 LF of pipeline located within roadways, including new pipelines to redirect flows. This Capital Improvement Project (CIP) is identified as CIP #1 in the City of Lomita 2025 Sewer System Master Plan (Master Plan).

CIP #1 will require long-term planning, including a preliminary design level analysis to determine project feasibility and the optimum alignment. As such, the Master Plan provides a near-term alternative to divert a portion of the flow upstream of the deficient pipelines to the Los Angeles County Sanitation District trunk sewer along Western Avenue, thus increasing available capacities of these existing pipelines and eliminating pipeline deficiencies. This diversion improvement is designated as DIV #1 and documented in the Master Plan with the location illustrated on Figure 1, attached.

Harbor Hills Sewer
The sewer basin tributary to the back yard pipeline includes the 301-unit Harbor Hills Public Housing Development (Harbor Hills), owned by the Los Angeles County Housing Authority.

Sewer plans obtained for Harbor Hills (Attachment A) were discovered early in the master planning process and it was determined that the site discharges to the north, toward the back yard pipeline as illustrated on Figure 1. The Harbor Hills on-site sewers are included in the Los Angeles County Consolidated Sewer Maintenance District’s (CSMD) online mapping shown in green on Figure 2.

Jenn Howell

Page 2 of 3 ends

August 8, 2024
2 Further review of the tributary basin was conducted to define the area tributary to the proposed flow diversion location (DIV #1) and calculate the amount of flow that could potentially be diverted away from the back yard pipeline. The review of as-built plans (Attachment A) found that the neighborhood located immediately west of Harbor Hills discharges through the Housing Authority site via the on-site sewers. These private/on-site sewers are illustrated by yellow dashed lines on Figure 1. As a result, City sewer flows are being routed through City pipelines, then through the private/on-site pipelines within LA County Housing Authority property, then back to City pipelines. The areas within the City that are tributary to the Harbor Hills on-site sewers are illustrated in Figure 3 based on the as-built plan research.

City sewer flow through the Harbor Hills on-site system has been estimated based on the tributary land use data and flow factors developed in the Master Plan. The City flow through Harbor Hills is summarized in Table 1 below. This flow is in addition to the on-site flow from Harbor Hills, also summarized in Table 1.

Table 1: Flow Through Harbor Hills On-Site Sewer
Land Use
Residential
Units Acres
ADWF
(gpm)1
PDWF
(gpm)2
Off-Site
Commercial 0 6.6 7.2 12.3
Low Density Residential 120 20.9 17.5 31.5
Total Off-Site 120 27.5 24.7 43.8
On-Site
Harbor Hills Housing 301 27.0 20.9 37.6
Total 421 54.5 45.6 81.4
(1) Existing average dry weather sewer flow
(2) Existing peak dry weather sewer flow
Recommendations
The GIS mapping available through the CSMD shows the identified tributary areas routed away from Harbor Hills, contrary to the as-built plans. The neighborhood located to the west of Harbor Hills is shown discharging toward Eshelman Avenue as shown on Figure 2.

Additionally, the pipeline along Western Avenue, adjacent to Harbor Hills, is shown discharging to the south (Figure 2). The CSMD designates the Harbor Hills on-site pipelines in their GIS mapping as “Non-CSMD Sewers.” As such, these sewers are not being maintained by the CSMD on behalf of the City, and it is doubtful the Housing Authority is maintaining them.

Jenn Howell

Page 3 of 3 ends

August 8, 2024
3 The Harbor Hills on-site sewers carrying City flows are illustrated Figure 1 and Figure 3.

The following is recommended for the continued reliability and maintenance of these sewers to serve City flows:

1. Meet with CSMD to discuss corrections to their GIS mapping and the Harbor Hills on-site sewers carrying City sewage.

2. Contact Harbor Hills and/or the Los Angeles County Housing Authority to determine existing maintenance practices, if any.

3. Conduct closed-circuit television (CCTV) inspection and condition assessment of the on-site sewers carrying City sewage. This can be done by CSMD or a private company.

4. Coordinate with the Los Angeles County Housing Authority for the City to discuss financial arrangements for City acquisition of these sewers along with a right-of-way for access.

5. Coordinate with the CSMD to add these sewers to their service area for ongoing inspection and maintenance.

Enclosures:

Figures 1 through 3, Attachment A
Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
Legend
DIV #1
Back Yard Pipe Basin
County Pipeline
Out of Service County Pipe
261st Street Western Ave. BACK YARD PIPE
262nd Street
SMP DIV #1
Flow Diversion Alternate
Diversion Location
Harbor
Hills
Housing
Harbor Hills
On-Site Sewers
Carrying City
Sewage
Harbor
Hills
Housing LACSD Trunk Sewer
FIGURE 1
Flow Diversion Improvement / Harbor Hills Sewer
PCH Eshelman Ave.

FIGURE 2
CSMD On-line GIS Mapping Flow Direction
on As-Built Plans
HARBOR
HILLS
Eshelman Ave.

HARBOR
HILLS
Sources: Esri, HERE, Garmin, USGS, Intermap, INCREMENT P, NRCan, Esri Japan, METI, Esri China (Hong Kong), Esri Korea, Esri (Thailand), NGCC, (c) OpenStreetMap contributors, and the GIS User Community
Legend
Harbor Hills Tributary
Back Yard Pipe Basin
County Pipeline
Out of Service County Pipe
263rd Street 262nd Street
Harbor
Hills
Housing
Harbor Hills
On-Site Sewers
Carrying City
Sewage
Harbor
Hills
Housing LACSD Trunk Sewer Harbor Hills Sewer
FIGURE 3
Area Tributary to Harbor Hills On-Site Sewer

ATTACHMENT A

AS-BUILT SEWER PLANS
HARBOR HILLS HOUSING SEWER PLANS (1939)
1 2
3 4
16 21
Western
193'
Western
223'
Western
248'

185'

LATER REVERSED FLOW
(TRACT NO. 25201)
TRACT NO. 25201 SEWER PLANS (1966)

Lomita City CouncilOctober 15, 2024

Lomita City Council
October 15, 2024