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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Watershed Physical Processes Research » Research » Research Project #442612

Research Project: Watershed Legacy Sediment Assessment

Location: Watershed Physical Processes Research

Project Number: 6060-13000-029-022-I
Project Type: Interagency Reimbursable Agreement

Start Date: Sep 16, 2022
End Date: Sep 15, 2027

The objectives of the proposed study are: 1. Explore tools used to identify and document sources of legacy sediment in agricultural watersheds; 2. Enhance large-scale analytical remote-sensing and GIS techniques and tools to identify legacy sediment sources; 3. Assess legacy sediment remobilization in the Goodwin Creek and Little Washita River CEAP watersheds; and 4. Assess the dynamics between sediment and nutrients for legacy sediment pools (banks and ponds) within Goodwin Creek and Missisquoi River watersheds. ----------------------- 5. Develop regional and national relationships between legacy sediment stored in reservoirs and climate, landscape and reservoir attributes.

I. To delineate probable sources of soils and sediments at the watershed scale, test: (1) GIS techniques applied to remote sensing products (e.g., 3DEP aerial lidar data, NHDPlus Hires hydrography data, LCMAP land cover data, SSURGO soils data, etc.), and (2) a suite of sediment tracing methods. Use reconnaissance techniques (e.g., UAS, walks, or others) to develop a watershed-scale channel conditions database for follow-up analysis using methods such as BANCS. The developed tools will be tested on the ARS Goodwin Creek, MS, and Little Washita River, OK, CEAP watersheds, and the Missisquoi River watershed, VT, which have historic data available on channel adjustment, reservoir sedimentation, or phosphorus concentrations in fluvial sediments. II. Using, among others, tools from Goals 1 and 2, enhance existing databases with data from eroding legacy sediment areas within the ARS Goodwin Creek, MS, and Little Washita River, OK, CEAP watersheds. These areas should cover at least two different sediment source types (e.g., upland, channel, or reservoir/pond). Use collected data for process understanding and begin development of enhancements, and initial testing, of ARS computer modeling technology that span the full range of sediment sources and transport, fate, and delivery processes, e.g., RUSLE-AnnAGNPS-CONCEPTS. III. Collect N and P data from eroding legacy sediment pools within the ARS Goodwin Creek, MS, CEAP watershed. Enhance and update the existing (dating from 2010) data set of channel adjustment and bank material phosphorus concentrations of the Missisquoi River watershed, VT, with current adjustment, phosphorus, and nitrogen data. Use these data sets to improve process understanding of N and P remobilization at eroding legacy sediment sites. ---------------------- IV. Using a combination of echosounders determine sedimentation rates of reservoirs constructed as part of USDA Watershed Programs across a broad range of geographic, climate, topographic, land use, soil, and reservoir parameters. Collect cores for grain size analysis, N and P concentrations, and sediment dating. Combine these new data with previously published studies into a comprehensive database of small reservoir sedimentation. Use this database to develop regional and national relationships between reservoir sedimentation and climate, geography, topography, soil, land use, and other parameters.