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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Hydrology and Remote Sensing Laboratory » Research » Research Project #442598

Research Project: Watershed Legacy N – Source Determination and Influencing Factor Assessment

Location: Hydrology and Remote Sensing Laboratory

Project Number: 8042-13610-030-051-I
Project Type: Interagency Reimbursable Agreement

Start Date: Sep 19, 2022
End Date: Sep 19, 2027

The overall goal of this project is to identify sources of legacy nitrate in fields and watersheds and to assess conservation options to capture and treat these sources. This project will obtain data and process understanding that can be utilized by the SWAT+ modeling team to improve the algorithms and assumptions concerning groundwater transit times in different regions of the U.S. Phase 1 will involve point in time watershed sampling, acquisition of additional data, and development of a plan for the next phase. In Phase 2, we will synthesize the data streams and examine the variance of input sources and the possible factors affecting delivery of legacy N to stream and surface waters. While nitrogen is typically delivered via groundwater, overland flow provides much of the phosphorus and sediments to surface waters. Thus, throughout the project, the team will consult regularly with the Legacy P and Legacy Sediment teams to coordinate efforts to maximize synergies, to share data streams on one platform, and to address competing processes in nutrient delivery so that we can advance a more holistic understanding and simulation of processes going forward.

1. Evaluate previously acquired WLTP project measurements and initial findings on land use, soil properties, drainage characteristics and known flow pathways, cropping systems, and conservation implementation to ascertain which watersheds across the country require further investigation. 2. Assess the influence of drainage management systems on the dynamics of nitrate delivery to waterways. 3. Consider the additional sites in under varying agronomic practices. 4. Coordinate with identified watersheds and collect point in time samples (monthly or more frequently depending on watershed attributes and weather). 5. Interface with ongoing isotopic tracer studies at various locations in assessment of multi-transient tracer approaches in assessing uncertainties. 6. Increase collaboration with USGS National Water Quality Program to assess nitrate and MESA dynamics in the larger tributaries within the Mississippi basin. 7. Meet with modeling teams and share initial results to discern next steps for improvements 8. Develop Phase 2 proposal for the project.