TMDL Investigations

The San Diego Water Board works collaboratively with stakeholder groups to address impaired water bodies throughout the region. The development steps of a TMDL investigation include assessing the water body, defining total loads, developing allocations, and implementation plans to address the water quality impairment(s).

A TMDL investigation may result in adopting a TMDL as a Basin Plan amendment, or alternative restoration plans may be identified to address water quality impairments. Some examples of alternative plans include use of existing permits such as the Regional MS4 Permit, investigative orders, and cleanup and abatement orders. TMDL projects that currently are under development.

TMDL Projects
Santa Margarita River Estuary
Tijuana River


Lagoons Investigations:
TMDLs for Impaired Lagoons, Adjacent Beaches, and Agua Hedionda Creek


Many of the TMDL investigations in and around San Diego Bay resulted in adopted enforcement orders in lieu of adopted TMDLs as Basin Plan amendments. Additional information on San Diego Bay sites can also be found in GeoTracker.

San Diego Bay Investigations:
Downtown Anchorage (Laurel Hawthorn Central Employment)
Mouth of Chollas Creek
Switzer Creek (Tenth Avenue Marine Terminal)