
State-of-the-Art Modeling Could Help Improve Gulfs Water
QualityBy Jennifer
Arnold September 27, 2001State-of-the-art
techniques--combining remote sensing and environmental modeling--can help
Mississippi Delta farmers choose the best management practices (BMPs) to reduce
the amount of eroded sediments that enter oxbow lakes and rivers in the
7,000-square-mile, cotton-producing Delta. Oxbow lakes are formed when a river cuts a new path across a large bend,
usually during flooding, isolating a U-shaped section of the river. Because of
the large amount of agricultural farmland in the Mississippi Delta, BMPs have a
great impact on sediment reaching the numerous oxbow lakes and rivers of the
Delta and ultimately the Gulf of Mexico. Agricultural Research Serviceagricultural engineer Ron Bingner and ARS agronomist Seth Dabney with the
National
Sedimentation Laboratory, Oxford, Miss., conducted a watershed modeling
analysis of a Delta farm. Bingner also worked with ARS hydraulic engineer Jurgen Garbrecht using
TOPAZ--topographic parameterization.
TOPAZ uses
Geographic Information Systems data and computer technologies to define and
analyze land surface, watershed configuration and drainage features. The tool
correctly identifies the remotely sensed land characteristics. TOPAZ-derived information is needed to ensure that accurate data is
available to run AGNPS 2001, the Agricultural Non-Point Source Pollution
Modeling System. AGNPS predicts soil erosion and nutrient transport/loadings
from agricultural watersheds for real or hypothetical storms. This analysis showed that combining cover crops with no-tillage systems can
reduce by up to 65 percent the amount of sediment leaving farms. Adding holding
ponds can decrease sediment losses by as much as 90 percent. This modeling
technology can help U.S. Department of Agriculture's
Natural Resources Conservation Serviceand Extension personnel in Mississippi aid farmers in evaluating and selecting
BMPs that are economically feasible as well as beneficial. ARS is the U.S. Department of
Agricultures chief scientific research agency. U.S. Department of Agriculture |