San Diego Region - Total Maximum Daily Loads (TMDLs)

Introduction

The Total Maximum Daily Load (TMDL) program is required under Clean Water Act (CWA) Section 303(d). There are streams, lakes and coastal waters within this Region that do not meet certain water quality standards. CWA Section 303(d) addresses these waters by requiring states to identify the waters and develop total maximum daily loads (TMDLs) for them. A TMDL is a quantitative assessment of water quality problems, contributing sources, and load reductions or control actions needed to restore and protect bodies of water. The TMDL approach does not replace existing water pollution control programs. It provides a framework for evaluating pollution control efforts and for coordination between federal, state and local efforts to meet water quality standards. TMDLs are adopted as amendments to the Basin Plan. More information is available in the TMDL Program Fact Sheet.

TMDLs Adopted by Regional Board

• Chollas Creek Diazinon TMDL adopted August 14, 2002
• Rainbow Creek Nitrogen and Phosphorus TMDLs adopted February 9, 2005
• Shelter Island Yacht Basin Dissolved Copper TMDL adopted February 9, 2005
• Chollas Creek Copper, Lead, and Zinc TMDLs adopted June 13, 2007
• Indicator Bacteria TMDLs
  • Revised Project I - Twenty Beaches and Creeks in San Diego Region (including Tecolote Creek)
    adopted February 10, 2010
  • Project II - Baby Beach in Dana Point Harbor and Shelter Island Shoreline Park in San Diego Bay adopted June 11, 2008
• Los Peñasquitos Lagoon Sediment TMDL adopted June 13, 2012

TMDLs in Process

• San Diego Bay Marine Sediments TMDLs
  • Mouth of Chollas Creek
  • Seventh Street Channel (Paleta Creek)
  • Switzer Creek
  • B Street/Broadway Piers
  • Downtown Anchorage
  • Naval Station Submarine Base
• TMDLs for Impaired Lagoons, Adjacent Beaches, and Agua Hedionda Creek
• Tijuana River and Estuary

Websites

For more information on TMDLs:

The U.S. Environmental Protection Agency has a webpage on the TMDL Program under section 303(d) of the Clean Water Act. Information on this page includes: status of 303(d) lists, TMDL program documents, TMDL Federal Advisory Committee, TMDL lawsuit information, and other links.

Region 9 of the EPA covers Arizona, California, Hawaii, Nevada, the Pacific Islands subject to U.S. law, and approximately 140 Tribal Nations. EPA Region 9's webpage on TMDLs also includes the status of California's 303(d) list and several finalized TMDLs.