Water Quality Survey

Jan 01, 2017

The Water Surveys Section was initally created as a part of the TMDL Program, sponsored by the Environmental Protection Agency (EPA). In 1972, the "Clean Water Act", developed by the EPA, implemented pollution control programs such as settling water quality standards for all contaminants in surface waters. Total Maximum Daily Load (TMDL) is the amount of a pollutant a waterbody can assimilate without exceeding the established water quality standard for that pollutant. The Water Survey Section performs intensive surveys on impaired waterbodies of Louisiana, which are listed on the EPA's 303(d) list.


During a survey on a watershed, a wide range of biological, physical and chemical data is collected by Environmental Scientists then evaluated by DEQ's modelers. Environmental Scientists employ several methods of collecting data such as time-of-travel, stream geometry, water quality, disharges, reaeration, stream flow, etc. Assessment of data may eventually result in revisions in the water quality standards set or a delisting of a waterbody deemed to be meeting current standards.