Total Maximum Daily Load  (TMDL) Program

Louisiana New Vision Program

Louisiana TMDL Process Information

TMDL Water Quality Modeling

  • TMDL Program Brochure
  • LDEQ Developed TMDL Reports and Models for Louisiana
  • Ultimate Biochemical Oxygen Demand Analysis
  • Water Quality Surveys for TMDL Development
    • 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.

Ambient Water Quality Data

The Louisiana Department of Environmental Quality collects ambient surface water data at approximately 125 sites across the state each month. This data is used for establishing water quality criteria or standards, assessment of conditions, and development of Total Maximum Daily Loads (TMDLs). TMDLs are one means of establishing water quality discharge permit limits and Nonpoint Source Pollution reduction recommendations for the protection and improvement of surface water quality in Louisiana.

Over 600 monitoring sites have been established since 1958 but not all sites are currently in use. Data has been collected at some of these sites since the inception of the program; however, most sites were established more recently. In 1998 the department established a rotating basins monitoring program in order to expand the coverage of our monitoring efforts. Under this plan approximately 100 sites are selected each year for monitoring once a month. In addition, 21 sites on 16 water bodies are monitored every month of every year as long-term trend sites.

The public may also obtain the data by contacting Public Records. Please provide Public Records with site numbers obtained from Ambient Water Quality Monitoring Sites and parameters of interest from Ambient Water Quality Parameters.  For questions regarding Louisiana's ambient water quality monitoring program please contact the Water Planning and Assessment Division, Water Quality Standards and Assessment section.

Ambient Water Quality Data online query tool

TMDL Public Participation

USEPA TMDL Information

Other Helpful Links


For questions concerning Louisiana's TMDL program, please contact Chuck Berger. Phone: 225-219-3217

e-mail: Click on TMDL Contact