Water: Nonpoint Source Success Stories
Louisiana (Section 319I - 1994)
Louisiana's goal is to work with agencies at all levels to address all categories of nonpoint source pollution through statewide education and targeted watershed projects. The state uses a committee made up of some 18 state and federal agencies to implement both statewide and watershed projects to reduce nonpoint source pollution and improve water quality.
BMPs Replace Mudding-In for Growing Rice
In the Mermentau River Basin, most of the land is used for agriculture, and rice is the major crop produced there. When Louisiana discovered that 75 percent of the waters draining into the Mermentau River Basin did not meet their designated uses, the state decided to act on the water quality problems caused by rice production. According to the 1992 water quality inventory, 12 of the 16 water quality management subsegments were either not meeting or only partially meeting their designated uses. These problems stemmed from rice production, a major agricultural commodity in the state. Data showed that levels of organic carbon, nutrients, and sediment all increased during the spring rice planting season, while dissolved oxygen declined to levels as low as 0.2 to 0.5 mg/L.
Section 319 cooperative agreements in FY 1988 and 1989 and again in FY 1990 and 1992 allowed the Louisiana Department of Environmental Quality (LDEQ) to address these water quality problems by establishing a rice demonstration project to evaluate four alternative best management practices.
LDEQ contracted with Louisiana State University (LSU) Agricultural Center to evaluate alternatives to the - traditional practice of "mudding-in." Mudding-in is a cultural practice that has been used in southwest Louisiana for generations to control red rice. This rapidly spreading, non-harvestable weed chokes out desirable rice plants. In mudding-in, also called dragging or muddy water planting, farmers plow the flooded fields and release the water immediately. This practice takes along sediment and other undesirable materials.
The alternative BMPs are:
- Water planting in previous crop residue;
- Retention of flood water in a closed levee system during and after soil disturbing activities;
- Clear water planting into a prepared seedbed; and
- Mudding-in with the use of vegetated filter strips.
LSU found that using alternative BMPs over two years decreased sediment loading from 20 to 63 percent and organic carbon by as much as 92 percent. Working cooperatively with the SCS and ASCS, LDEQ began educational programs and technical assistance to encourage rice farmers to adopt the new management practices. The LSU Agricultural Center reviewed the BMPs and will put more emphasis on solving water quality problems associated with rice production in Louisiana. By 1994 a total of 39,779 acres of rice had been planted with the new BMPs. One of the latest project components, funded with FY 1991 section 319 monies, is to correlate results from BMP implementation with in-stream and edge-of-field water quality data to estimate how load reductions translate into water quality improvement.