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Water: Nonpoint Source Success Stories

Mississippi Success

Story 1  |  Story 2  |  State Water Quality Site  Exit EPA Disclaimer



  Contact   Primary Sources of Pollution
  • agriculture (animal operations, crops)
  • forestry
  Primary NPS Pollutants
  • Sediment
  • Nutrients
  Project Activities
  • conservation tillage
  • streambank stabilization
  Results
  • retention of more than 3,500 tons of soil annually
Muddy Creek Watershed Demonstration Project:
BMPs Retain 3,500 Tons of Soil per Year

 

Winding its way through the northern part of Tippah County, Mississippi, Muddy Creek eventually flows into Tennessee. The creek's drainage area encompasses a total of 67,070 acres, of which approximately 42 percent is in cropland, 31 percent in pastureland, and 25 percent in forest. Four dairy, 300 timber, 100 livestock, and 20 swine operations are also in the watershed. The main agricultural products are soybeans and corn. Classified as a Fish and Wildlife area, Muddy Creek is designated as suitable for secondary contact recreation, such as wading and occasional swimming. Of primary concern to the local population and the neighboring population in Tennessee was the amount of sediment and nutrients emptied by this creek into the Hatachie River in Tennessee, designated as a Wild and Scenic River.

Water quality and land use assessments were performed in the watershed, and 3 of the 10 tributaries were identified as having the most agricultural operations. The land use assessment evaluated the average soil erosion rate and the magnitude of the animal operations in the watershed. The average soil loss from cropland and pastureland in the watershed was estimated at 12.2 tons per acre per year. This amount of sediment entering the watershed gave it a designation as a priority watershed on the state's priority watershed list for agricultural nonpoint source pollution.

Installing best management practices

To address these concerns, the Muddy Creek Watershed Demonstration Project was initiated by establishing demonstration farms and agricultural best management practices (BMPs). Conservation tillage was widely promoted and accepted throughout the watershed. The purpose of conservation tillage is to reduce ground disturbance before crop planting, so that less soil and pollutants leave the field and enter the receiving stream.

Other BMPs included grade stabilization structures (pipes), a pond, more than 2,500 feet of diversion (a constructed ridge diverting the flow of water), fencing, critical area planting (pine trees), and streambank protection. Streambank stabilization BMPs included earthwork, vegetative cover, and rock riprap.

Dramatic reductions in erosion

As a result of the BMPs installed, more than 3,500 tons of soil is being retained on the land each year. The BMPs dramatically reduced the amount of annual soil erosion and the subsequent flow of sediment into the Muddy Creek watershed.

 



Story 1  |  Story 2  |  State Water Quality Site  Exit EPA Disclaimer



  Contact   Primary Sources of Pollution
  • agriculture (animal operations, crops)
  • forestry
  Primary NPS Pollutants
  • Sediment
  • Nutrients
  Project Activities
  • conservation tillage
  • streambank stabilization
  Results
  • retention of more than 3,500 tons of soil annually

Roebuck Lake Demonstration Project:
Slotted-Board Risers Installed to Save Topsoil & Improve Water Quality

 

Roebuck Lake is a 580-acre lake in the Bear Creek watershed in the central part of LeFlore County, Mississippi. Its watershed encompasses an area of 11,200 acres. Roebuck Lake has tremendous potential as a multiple-use recreational lake because some 101,500 people live within a 25-mile radius. In the past the lake was well known for water-skiing, swimming, boating, and fishing, but currently these uses have decreased.

The water quality in Roebuck Lake is degrading because of the inflow of pollutants from cropland fields. Drainage from approximately 8,100 acres of delta cropland flows into the lake, leaving deposits of silt, pesticides, and fertilizer and other plant nutrients. Erosion occurring from these erodible cropland acres is excessive, at an average rate of 8 tons per acre. Based on available data, the lake was designated in the state's 305(b) water quality report as only partially supporting its fish and wildlife classification because of agricultural nonpoint sources of pollution.

Installing slotted-board risers

A number of partners came together to address these concerns: the Mississippi Department of Environmental Quality; U.S. Department of Agriculture, Natural Resources Conservation Service; Mississippi Soil and Water Conservation Commission; Environmental Protection Agency; and Mississippi Cooperative Extension Service. The project included installing grade-stabilization structures called slotted-board risers (SBRs) on a selected cotton farm site. The practice involves placing a pipe at the edge of the field just after harvesting, with slotted boards placed in front of the pipe, and allowing the field to flood. Valuable topsoil and expensive nutrients are retained on the field, allowing them to be used during the next growing season

Significant reductions

During the winters of 1997 and 1998, automated storm water monitoring equipment was used to calculate the loading reductions resulting from the use of the SBRs. Because most of the rainfall runoff was contained on-site and did not produce a discharge, reduction percentages were high. Most of the trapped rainwater evaporated or was absorbed into the soil. The results included reductions of 99.8 percent total suspended solids, 89.4 percent total organic carbon, 100 percent total Kjeldahl nitrogen, 90.7 percent ammonia nitrogen, 96.3 percent nitrate/nitrite, and 97.1 percent total phosphorus. Overall, the grade stabilization structures are saving 4,950 tons of topsoil per year.

The SBR practice continues to prove that it is a very cost-effective approach to saving topsoil while at the same time improving the lake's water quality. Many farmers have installed SBRs on their fields since the project was initiated. It is still too early to determine what long-term effects these best management practices (BMPs) will have on Roebuck Lake's water quality. It is hoped that through this demonstration and through subsequent field days, farmers and the public will take what they have learned and apply it to their lands. If this occurs, it is possible that Roebuck Lake could once again support its fish and wildlife designated use.

 

Story 1  |  Story 2  |  State Water Quality Site  Exit EPA Disclaimer
Wetlands, Oceans & Watersheds | Watershed Protection

 


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