Joint Water Pollution Control Plant Effluent Outfall Tunnel Western Avenue Boring
Summary
SCH Number
2025110204
Public Agency
Los Angeles County Sanitation District
Document Title
Joint Water Pollution Control Plant Effluent Outfall Tunnel Western Avenue Boring
Document Type
NOE - Notice of Exemption
Received
Posted
11/6/2025
Document Description
The project consists of emergency boring/drilling along Western Avenue of up to fourteen exploratory boreholes for the Joint Water Pollution Control Plant Effluent Outfall Tunnel Project to aid in the investigation of a partial tunnel breach that took place on July 9, 2025. Access into the breached tunnel is currently prohibited by Cal OSHA and boring/drilling effort down to the tunnel elevation (up to 365 feet below ground surface) is the only method to investigate the current tunnel condition. A potential void was found over the tunnel breach and emergency investigation and repair will be required to prevent potential additional settlement of the surrounding areas. After the boring/drilling campaign is completed, the boreholes will be abandoned in accordance with the Los Angeles County and California Well Standards.
Contact Information
Name
Patricia L Horsley
Agency Name
Los Angeles County Sanitation Districts
Job Title
Environmental Planner
Contact Types
Lead/Public Agency
Phone
Email
Location
Cities
Los Angeles
Counties
Los Angeles
Regions
Southern California
Other Location Info
The project is located along the tunnel alignment in Western Avenue, approximately 600 feet south of Weymouth Place in the City of Los Angeles.
Notice of Exemption
Exempt Status
Emergency Project
Type, Section or Code
Sec. 21080(b)(4); 15269(b)(c)
Reasons for Exemption
The project includes emergency repairs to a publicly owned service facility necessary to maintain service essential to public health, safety or welfare.
Exempt Status
Statutory Exemption
Type, Section or Code
Section 21080(b)(4) of the Public Resources Code
Reasons for Exemption
The project is necessary to prevent or mitigate an emergency.
County Clerk
Los Angeles
Attachments
Notice of Exemption
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