Water Surveys


The Water Surveys Section was initially created as a part of the TMDL Program, sponsored by the Environmental Protection Agency (EPA). In 1972, the Clean Water Act (CWA), 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 and evaluated by DEQ's modelers. Environmental Scientists employ several methods of collecting data such as:

  • water quality (in-situ measurements and sample collection)
  • stream geometry
  • time-of-travel studies
  • discharges
  • stream flow

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.


The Water Surveys Section collaborates with LDEQ's Non-Point Source Section to help plan and execute several water quality projects through field data assessment and sample collection. Section 319 of the Clean Water Act required that the states develop a plan to reduce and control various types of NPS pollution, which comes in the form of agriculture and urban runoff, home sewage systems and many other sources. Water Surveys is tasked with reconnaisance of accessible and representative sites for each project, as well as adhering to monthly or bi-monthly water sample and flow measurement collection schedules. Their efforts provide a qualitative and quantitative  assessment of a waterbody and help identify potential "hotspots" for non-point source pollution. With the help of Louisiana Department of Agriculture and Forestry (LDAF) and the implementation of Best Management Practices (BMPs), LDEQ is hoping to educate local entities of how their land use practices can adversely affect local waterbodies.

Bayou Chene - NP2012014 - Bayou Chene is listed as impaired for not meeting its designated use for fish and wildlife propagation due to low dissolved oxygen concentrations stemming from numerous agricultural practices. View the Watershed Implementation Plan here.

Queue de Tortue - NP2013001 - Bayou Queue de Tortue is fully meeting primary and secondary contact recreation uses but is impaired for fish and wildlife propagation because of high concentrations of nutrients, total suspended and dissolved solids, low dissolved oxygen, turbidity and mercury in fish. Agricultural practices are the suspected sources. View the Watershed Implementation Plan here.

Bayou Lafourche - NP2013003
Bayou Louis - NP2013005
Boston Canal - NP2013006

Comite River - NP2013010 -
Comite River was selected by LDEQ, USDA, and LDAF as one of Louisiana's priority waterbodies to partially and/or fully restore by October 2022. Comite River is impaired for primary and secondary contact recreation because of fecal coliform. Suspected sources are on-site sewage treatment plants and sanitary sewer overflow. 

Big Creek North - NP2015002 - Louisiana's 2016 Integrated Report indicated that Big Creek was not supporting its designated use for fish and wildlife propagation (FWP); however, it was fully meeting SCR and PCR uses. The suspected cause of NPS impairment is turbidity from agricultural practices. BMPs are in the early stages of developmentas of April 2018.

Bayou des Cannes - NP2015003 -
Louisiana's 2014 Integrated Report indicated the bayou was not supporting its designated use for fish and wildlife propagation (FWP); however, it was fully meeting SCR and PCR uses. Currently, suspected causes of impairment include nitrate-nitrite, low dissolved oxygen, total phosphorus, and turbidity, due to agricultural and natural sources. BMPs to be implemented include irrigation land leveling, grade stabilization structures, residue management, irrigation water management/dry seeding of rice, and shallow water for wildlife. 

Hemphill Creek - NP2016002 - Louisiana's 2016 Integrated Report indicated that Hemphill Creek was not meeting its PCR designated use due to high concentrations of fecal coliform. The suspected sources include livestock and sewage discharge in unsewered areas. Since partnering with LDAF, LDEQ will continue long-term monitoring in conjunction with LDAF's implementation of BMPs. The addition of nutrient data will inform LDEQ's nutrient management strategy group of the state of nutrients in this watershed and will support the fecal coliform data by providing valuable information about the overall health of the watershed.  

Bayou Vermilion - NP2016003

Lake Providence - NP2017001

Bayou de Portage - NP2017002
- During LDEQ's ambient water quality monitoring of a site located on Bayou Portage, data collected indicated that dissolved oxygen, turbidity, and fecal coliforms violated the state's standards for fish and wildlife propagation and for primary and secondary contact recreation. Agriculture practices dominated by surgarcane, pasture, rice and aquaculture are suspected contributors.


Bayou Grosse Tete - NP2018001

Bayou Maringouin - NP2018002

NEW VISION PROJECTS - CLEAN WATER ACT SECTION 303(D)Natalbany River - Subsegment 040503

Yellow Water River - Subsegment 040504

For information on LDEQ's Long-Term Vision for Assessment, Restoration, and Protection Program, click here.


Video courtesy of Smith-Root

Evaluation of Dissolved Oxygen in Inland Rivers and Streams within Louisiana's Southern Plains Terrace and Flatwoods (SPTF) Ecoregion - DEQ is conducting a Use Attainability Analysis (UAA) in the SPTF ecoregion to determine appropriate water quality criteria to support the fish and wildlife propagation designated use. 

An ecoregion is a relatively homogeneous area of similar ecological characteristics such as:

  • climate
  • land use
  • soils
  • potential natural vegetation
  • hydrology
  • other ecologically relevant variables

Because of the similarity and homogeneity of ecological characteristics within an ecoregion, an ecoregional approach provides a framework for determining appropriate water quality standards by water body type on a regional basis.

Data collected at designated reference sites in the SPTF ecoregion will help develop ecoregion-wide dissolved oxygen criteria.