Designing Research to Improve Runoff and Erosion Control Practices: Example, Grass Hedges

Soil and water conservation research often focuses on a better understanding of the principles, processes, and mathematics of the system but stops short of the important goal of developing improved control practices. Also, acquisition of accurate and pertinent data for improved models and relationships is often lacking. Studies to develop grass hedges as an erosion-control practice illustrate a productive research approach that provided both effective methodology and useful data. Experiences reported from scientists throughout the world provided a foundation from which to start. Indoor flume studies showed that grasses with tall, stiff stems were necessary to withstand concentrated flows. Tests were developed to evaluate plant stem strength. Sediment trapping effectiveness for different grasses of various hedge widths for different sediments at several flow rates was evaluated in a specially designed outdoor flume. Hedges were planted on standard erosion plots to test them under natural and simulated rainfall conditions. Stiff-grass hedges were then installed on a variety of cropland and critical area conditions to study their performance in field situations. Acquired data were used to improve erosion prediction relationships for conservation planning. The results were then incorporated into interim standards for stiff-grass hedges as an erosioncontrol practice to be used by action agencies. The effort to further improve this practice continues by researchers and scientists throughout the United States and many other parts of the world.