The Load Reduction Strategy (LRS) Adaptation Implements a More Efficient and Effective Strategy to Address the Los Angeles River Bacteria TMDL

There are many sources of bacteria in the environment and although elevated concentrations of traditional fecal indicator bacteria may indicate a higher potential for human health risks, it is exposure to pathogens that can cause illness in recreational water users and threaten or impair beneficial uses. Human waste typically contains a higher concentration of pathogens, as compared to other sources, thereby increasing the risk of gastrointestinal illness (GI) through recreational exposure.

The LRS Adaptation Plan provides an effective framework to address human health risk from pathogen exposure, by focusing on eliminating sources of human waste to the municipal separate storm sewer system (MS4). The Plan helps to streamline efforts across the ULAR agencies and other stakeholders in the watershed.

The LRS Adaptation Plan was submitted to the Los Angeles Regional Water Quality Control Board for review and approval on August 2, 2021.

Access the full Plan here.

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Funded by the Safe, Clean Water Program.
Access additional study reports here.

What Is Contributing to the Problem?

Human sources of bacteria in our waterways that cause disease or sickness in recreators can originate from a variety of common sources, including the following:

Pipe leaking brown water into a channel

Leaking Sewer Pipes &
Sanitary Sewer Overflows

Leaking sewer pipes and sanitary sewer overflows release raw sewage into the environment. Common causes are blockages, line breaks, vandalism, sewer defects, and aging infrastructure.

Leaking/Failing Septic System

Residential septic systems leak/fail due to poor maintenance or design. Failing systems leak raw sewage into surrounding soil and can ultimately end up in nearby waterways.

Septic tank linking into the surrounding ground
Tent housing on the sidewalks of Los Angeles

Homeless Encampments

Homeless encampments can lead to increased trash and human waste entering nearby waterways through bathing or direct deposition.

Illegal Dumping

Illegal dumping refer to the disposal of trash or debris into waterways. These can include human waste contributions..

Tire and other trash dumped illegally in waterway
Storm drain clogged with illegal discharge

Illicit Connections/Illicit Discharges

Illicit connections or discharges refer to connections to the MS4 or discharges into the MS4 that are not authorized. These can include human waste contributions.

Source Investigation Framework

To identify human fecal sources within the high priority, areas of investigation (AOIs), the Group will implement a human waste source investigation (HWSI) with the following steps.

Chart of ULAR's Source Investigation Framework

See Our Monitoring Team in Action

High Priority Areas In The ULAR WMA

The LRS Adaptation Plan prioritizes outfall catchment areas under dry and wet weather conditions utilizing a risk-based GIS desktop analysis of receiving water and outfall water quality conditions, potential presence of sources of human waste, and hydraulic connectivity to receiving waters.

In Partnership with the following:

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