What is a TMDL?
Section 303(d) of the Federal Clean Water Act requires states to establish maximum limits of pollutant(s) that streams, rivers, lakes, and oceans can accept before their beneficial uses such as swimming, fishing, and industrial uses are impaired. Such limits are referred to as Total Maximum Daily Loads (TMDL). Section 303(d) also requires the implementation of control measures over a predetermined schedule to meet the water quality objectives.
How is a TMDL developed?
A TMDL is developed by determining the maximum daily load of a pollutant that a waterbody can assimilate and meet Water Quality Standards. This load is then allocated to point source discharges, nonpoint source discharges, and a margin of safety reserve (to account for technical uncertainties).
Following development of a draft, a TMDL is noticed for public comment. After making any appropriate modifications in response to the public comment, the TMDL is sent to the United States Environmental Protection Agency for approval. Once approved, the state is required to implement the TMDL so the waterbody will meet Water Quality Standards. The TMDL is implemented through existing programs, such as NPDES permits for point source discharges and nonpoint source control programs, to achieve the necessary pollutant reductions.
How is it decided which waterbodies need TMDLs?
Each state identifies waterbodies within its boundaries which are not meeting Water Quality Standards and the reason why (for example, excess nutrients). For example, both Malibu Creek and the Santa Monica Bay have been named as requiring TMDLs.
Who is responsible for meeting these water quality standards?
The quality of our receiving waters has deteriorated due to expanding populations and continued urbanization. We are all responsible and the only way to change course is for us to begin changing our behaviour. By implementing best management practices (BMPs) at home and at work, we can each make a difference and preserve our natural habitat for future generations.
TMDL Updates:
On March 19, 2003, the State Water Resources Control Board approved a resolution adopted by the California Regional Water Control Board, Los Angeles Region which established a TMDL for bateria during wet weather at Santa Monica Bay beaches. The Santa Monica Bay Beaches Wet-Weather Bateria Total Maximum Daily Load Draft Implementation Plan has been prepared in response to this resolution in order to achieve compliance. Please click on the link below to view the Draft Implementation Plan. http://www.ladpw.org/wmd/nsmb/ADV_031505_DIP_Draft_Implementation_Plan.pdf.