Revised Total Maximum Daily Loads for Indicator Bacteria, Project I – Twenty Beaches and Creeks in the San Diego Region (Including Tecolote Creek)

Introduction

On February 10, 2010 the San Diego Water Board adopted Resolution No. R9-2010-0001, an Amendment to the Water Quality Control Plan for the San Diego Region to Incorporate the Revised Total Maximum Daily Loads for Indicator Bacteria, Project I - Twenty Beaches and Creeks in the San Diego Region (Including Tecolote Creek). This TMDL Basin Plan amendment was subsequently approved by the State Water Resources Control Board on December 14, 2010, the Office of Administrative Law (OAL) on April 4, 2011, and the United States Environmental Protection Agency (USEPA) on June 22, 2011. Under state law, this TMDL Basin Plan Amendment became fully effective on April 4, 2011, the date of OAL approval.

Revisions to Bacteria TMDLs in the San Diego Region

As part of the 2024/2025 Basin Plan Triennial Review, the San Diego Water Board has identified a project to update the region’s bacteria Total Maximum Daily Loads (TMDLs).

Additional information on this project can be found at: Water Recreation (REC-1) Water Quality Objectives

Why Bacteria in Water Matters

Fecal bacteria originate from the intestinal biota of warm-blooded animals. The presence of fecal indicator bacteria in the ocean and creeks can indicate the existence of human pathogens, which may pose health risks to individuals who come into contact with the water. Most strains of fecal indicator bacteria do not cause illness (i.e., they are not pathogens); rather, they indicate the presence of fecal contamination. However, pathogens often co-occur with indicators of fecal contamination. Fecal indicator bacteria have been historically used as indicators of human pathogens because these bacteria are easier and less costly to measure than the pathogens themselves.

Background

In 2003, the San Diego Water Board began work on a project to address bacteria pollution in various waterbodies across the region. This decision was based on the 2002 Clean Water Act Section 303(d) List of Impaired Waters, which showed that elevated bacteria levels were the most common cause of water quality problems in the San Diego Region. To address this, the Board made bacteria-impaired waterbodies a top priority for developing Total Maximum Daily Loads (TMDLs).  That TMDL project identified sources of fecal indicator bacteria and regulatory steps the Board would take to reduce chronic fecal contamination in many of our waters.

The first version of the project, called Bacteria TMDLs Project I, was adopted in December 2007. However, it was later withdrawn from State Water Board consideration in December 2008 to resolve several issues and make significant revisions.

The revised version, now called Revised Bacteria TMDLs Project I, expanded the scope to include Tecolote Creek and a total of twenty beaches and creeks in the region.

PUBLIC DOCUMENTS

Documents associated with the adoption of this TMDL are available for review at the San Diego Water Board Office. To request a file review please contact the Regional Board receptionist at (619) 516-1990, or email rb9_records@waterboards.ca.gov. Please include the project ID # 650426 with your request.

Documents available for public review include, but are not limited to:

• State Water Resources Control Board Resolution No. 2010-0064
• Resolution No. R9-2010-0001 and Basin Plan Amendment (adopted February 10, 2010)
• Final Technical Report and Appendices (dated February 10, 2010)