Future Water Erosion Research and Model Development Needs, USDA-ARS-National Sedimentation Laboratory

There is a critical need for an improved understanding and quantification of the processes that control: the movement of water across the landscape; the detachment and transport of soil and sediment; and the morphologic adjustment of channels. Research is needed that will use an integrated approach to watershed management through the development and testing of innovative practices and computational models based on a scientific understanding of hydrogeomorphic processes at the test-plot, farm, watershed, and river-basin scales. Field and laboratory, short- and long-term experiments are needed to fill technology and knowledge gaps in USDA erosion models concerning: ephemeral gully and soil pipe erosion; transport of eroded sediments and of sediments introduced by reservoir sediment management actions; and stream system physical integrity. New findings are needed to develop new computer modeling components that optimize conservation measure design and placement for existing technology at the field-scale (i.e., Revised Universal Soil Loss Equation, Version 2, RUSLE2), watershed-scale (i.e., Annualized Agricultural Non-Point Source model, AnnAGNPS), and channel-scale (i.e., CONservational Channel Evolution and Pollutant Transport System, CONCEPTS). Innovative experimental designs are needed to capture spatiotemporal topographic, agronomic and climatic information to develop and enhance state-of-the-art computer simulation/prediction models for sustainable agriculture. Long-term monitoring combined with new field experiments can be used to investigate the long-term sustainability of surface and groundwater resources in the Lower Mississippi River Valley. Research at the USDA-ARS National Sedimentation Laboratory includes developing new knowledge and methodologies to quantify soil detachment and sediment transport, transformation, storage, and delivery. This is accomplished through experiments that: determine the functional relations among erosion variables (i.e., rainfall, soil moisture, soil texture, bulk density, organic matter, vegetation); quantifies the surface and subsurface processes controlling erosion and deposition; and, quantifies the effects of mixed-particle sizes and bed forms on roughness and sediment transport. This research is then translated into technology to quantify and evaluate management effects on watershed physical processes. Erosion prediction technology needs the development of a GIS-based management system and a machine learning approach that facilitates database acquisition and input file development, output visualization, and supports multiple scales of focus, including: watersheds, farm fields, and streams. New computer model components are needed to simulate non-uniform sediment transport and stream morphologic adjustment at sub-reach scales. Conceptually, every system has a pattern. The research program at the National Sedimentation Laboratory seeks to understand and transform the scaled evolutionary pattern into a mathematical structure that is robust and effective to determine conservation management towards sustainable agriculture.