Location: Hydrology and Remote Sensing Laboratory
Project Number: 8042-13610-030-104-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2026
End Date: Apr 30, 2029
Objective:
Demonstrate an integrated, watershed-scale modeling framework that leverages existing datasets, geospatial products, and previously developed atmospheric, hydrologic, and agricultural models to improve understanding of nitrogen transport, evaluate conservation practices, and provide science-based decision support for sustainable agricultural production and water-quality protection in the Chesapeake Bay watershed.
Specific objectives are to:
1. Develop an integrated watershed database and modeling framework that leverages existing datasets and previously developed atmospheric, hydrologic, and agricultural models to improve understanding of nitrogen transport, evaluate conservation practices, and provide science-based decision support for sustainable agricultural production and water-quality protection in the Chesapeake Bay watershed.
2. Quantify watershed-scale nitrogen transport using existing models and datasets. Integrate poultry ammonia emission estimates, atmospheric transport and deposition (NOAA HYSPLIT), watershed nitrate loading (SWAT) using groundwater lag-time information (MESA tracer), and geospatial analyses to quantify the relative contributions of atmospheric deposition, groundwater, and surface runoff to nitrogen delivery under representative weather conditions and management scenarios. Evaluate interactions among atmospheric ammonia, legacy nitrogen, and legacy phosphorus that influence downstream nutrient loading.
3. Evaluate conservation and nutrient management scenarios using existing model outputs to assess the watershed-scale benefits of vegetative environmental buffers (VEBs), manure redistribution strategies, and other conservation practices on atmospheric deposition, watershed nitrogen loading, and potential impacts on downstream water quality. Compare alternative conservation scenarios to identify management strategies that improve nutrient use efficiency while reducing environmental impacts. Assess model performance and uncertainty.
4. Evaluate the predictive capability of the integrated modeling framework using observational datasets and standard statistical performance metrics (e.g., root mean square error). Identify key sources of uncertainty and the relative influence of atmospheric and hydrologic transport pathways on watershed nitrogen budgets.
5. Evaluate several models used to predict algal formation from nitrogen sources.
6. Communicate results to producers, NRCS conservation planners, and collaborating scientists to demonstrate the utility of integrated modeling for evaluating conservation practices.
Approach:
This demonstration project will integrate previously developed datasets, geospatial products, and numerical models without conducting additional large field measurements or experimental studies.
1. Compile existing GIS inventories of poultry houses, weather records, land use maps, watershed characteristics, VEB model outputs, groundwater lag-time estimates, and SWAT-derived nitrate loading data for the selected watershed.
2. Use previously developed poultry emission estimates as inputs to the NOAA HYSPLIT atmospheric dispersion model to simulate ammonia transport and deposition under representative meteorological conditions.
3. Integrate atmospheric deposition outputs with existing watershed model results, groundwater lag-time information, land use, and hydrologic datasets to estimate total nitrogen inputs to receiving waters.
4. Apply machine learning techniques to fuse atmospheric, hydrologic, and geospatial datasets and evaluate conservation scenarios, including varying levels of VEB implementation and alternative nutrient management strategies.
5. Assess model performance by comparing integrated model predictions with existing observational datasets using standard statistical measures, including root mean square error (RMSE); ground truth outputs at strategic locations; and conduct sensitivity analyses to identify dominant controls on nitrogen transport.
6. Communicate results through demonstrations, technical reports, and stakeholder meetings with producers, NRCS, conservation planners, and collaborating scientists to illustrate how integrated atmospheric-hydrologic modeling can support conservation planning and watershed management.