The City of South Gate (City) is in Los Angeles County, approximately seven miles south of the downtown area of the City of Los Angeles. With growing concerns about Sanitary Sewer Overflows (SSO) and in compliance with the Sanitary Sewer Systems and Monitoring and Reporting Program, the City recently updated an internal program audit report that completed a Sewer System Management Plan (SSMP).
The plan recommended that the City continue to evaluate and rehabilitate the sewer pipeline systems’ remaining 7% of concrete piping that had not been lined or replaced. This includes evaluating the remaining VCP piping in identifying structural damage, such as cracks or joint displacement.
Scope of Work
LEE + RO will perform inspections consisting of pipe cleaning, closed circuit television (CCTV), and structural integrity evaluation for all remaining unlined concrete sewer main, which consist of 7.3 miles or about 38,500 linear feet. Services include:
Design Services
LEE + RO will evaluate the extent of the risk associated with sewer pipeline rehabilitation and repairs. This evaluation will discuss the potential impact on sewer service interruptions, community safety, daily residential needs, and limited roadway access to local businesses.
Surveying
For the replacement segments, assumed to be 5% of the total project length of 7.3 miles, the surveying base map is a prerequisite for preparing design drawings.
Utilities and Potholing
Utility research is a due diligence effort during design to avoid costly change orders during construction. It involves looking up utility provider’s details along the alignment in Underground Service Alert (USA) Dig Alert’s Design Lookup database.
LEE + RO will mark the requested potholes on the design plans created using the survey and utility bases map.
Concept Alignment Options
For the replacement project, the existing sewer mains can be replaced with new pipes in the same trench or replaced with a parallel trench.
Street Restoration
For the replacement project, LEE + RO will develop the trench detail based on existing soil conditions following the City’s standards.
Sewer Main Pipe Cleaning and CCTV Survey Inspection
Sewer main pipeline inspections will be performed per the standardized guidelines and requirements specified under NASSCO PACP.
Pipe Rehabilitation and Replacement:
For the three pipeline segments, LEE + RO will perform a pipeline risk assessment under the NASSCO PACP guidelines to determine the current conditions, structural integrity, and usable remaining duration and verify if pipeline removal and replacement method is applicable or if CIPP lining method is a viable option in prolonging the durability and usefulness of the existing pipeline.