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United States Department of Agriculture

Agricultural Research Service

Research Project: Managing Water and Sediment Movement in Agricultural Watersheds

Location: Watershed Physical Processes Research

Project Number: 6060-13000-026-00-D
Project Type: In-House Appropriated

Start Date: Mar 13, 2017
End Date: Mar 12, 2022

Objective:
1. Develop new knowledge and methodologies to quantify soil detachment and sediment transport, transformation, storage, and delivery. 1a: Determine functional relations among variables (i.e., rainfall, soil moisture, soil texture, bulk density, organic matter, vegetation) with soil erosion. 1b: Quantify the surface and subsurface processes controlling erosion and depositional features. 1c: Quantify the effects of mixed-particle sizes and bed forms on roughness and sediment transport. 2. Improve knowledge of processes controlling surface and groundwater movement in agricultural watersheds, and their associated quantification. 2a: Quantify processes governing groundwater recharge and sustainable groundwater use for aquifers in agricultural watersheds. 2b: Assess the use and management of floodplain water bodies for providing ecosystem services in order to support their use as a sustainable source of water for agriculture. 2c: Quantify the processes partitioning components of the water budget in upland catchments of the Lower Mississippi River Basin. 3. Translate research into technology to quantify and evaluate management effects on watershed physical processes. 3a: Develop a GIS-based erosion prediction management system that facilitates database acquisition and input file development, output visualization, and supports multiple scales of focus, including: watersheds, farm fields, and streams. 3b: Develop technologies and tools to evaluate the benefits of conservation practice plans within and among fields, streams, and watersheds. 3c: Develop new computer model components to simulate non-uniform sediment transport and stream morphologic adjustment at subreach scales. 4. As part of the LTAR network, and in concert with similar long-term, land-based research infrastructure in the Midsouth region, use the Lower Mississippi River Basin LTAR site to improve the observational capabilities and data accessibility of the LTAR network and support research to sustain or enhance agricultural production and environmental quality in agroecosystems characteristic of the Midsouth region. Research and data collection are planned and implemented based on the LTAR site application and in accordance with the responsibilities outlined in the LTAR Shared Research Strategy, a living document that serves as a roadmap for LTAR implementation. Participation in the LTAR network includes research and data management in support of the ARS GRACEnet and/or Livestock GRACEnet projects. 4a: Develop the Lower Mississippi River Basin LTAR location addressing issues of long-term agroecosystem sustainability specific to the region, participating in the Shared Research Strategy, and contributing to network-wide monitoring and experimentation goals. 4b: Enhance the LMRB CEAP watershed long-term data sets and integrate with other long-term data sets in the LMRB to address agroecosystem sustainability at the basin scale. 5. Increase knowledge and understanding of the processes governing movement, storage, and quality of water in the Mississippi River Valley Alluvial Aquifer, and develop technologies to enhance the sustainability of water resources for agriculture.

Approach:
In the Lower Mississippi River Valley, groundwater extraction for irrigation has outpaced aquifer recharge, and precipitation is expected to fall in fewer, higher intensity events, thereby increasing runoff and stream peak discharges. This will impact erosion patterns and rates, destabilize streams with consequent loss of arable land, adversely impact ecosystem services, and reduce reservoir usability. These are not only regional but also national concerns. There is a critical need for 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. This research 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 will be conducted 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. Findings will be used to develop new computer modeling components to optimize conservation measure design and placement for the RUSLE, AnnAGNPS, and CONCEPTS computer simulation models. Long-term monitoring combined with new field experiments will investigate the long-term sustainability of surface and groundwater resources in the Lower Mississippi River Valley.

Last Modified: 09/22/2017
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