FAQs

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, non-point 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 non-point source control programs, to achieve the necessary pollutant reductions.

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Water Resources

1. 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, non-point 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 non-point source control programs, to achieve the necessary pollutant reductions.

2. 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.

3. 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 behavior. 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.