COUPLING SWAT AND WETQUAL FOR IMPROVED N, P, AND C PROCESSING IN WETLAND DOMINATED AGRICULTURAL WATERSHEDS

The major goal of this project is to create a model for improved representations of nitrogen (N), phosphorus (P), and carbon (C) cycles/processes in wetland rich watersheds, so that assessment of conservation practices impacts, BMP allocations, land use/cover (LULC) change and water quantity/quality nexus, TMDL development, etc., can be better carried out.The latest version of the Soil Water Assessment Tool, SWAT+, and the wetland nutrient cycling model, WetQual, will be fully coupled, resulting in a coupled model called SWAT+Wet in order to achieve this goal.This goal will be accomplished through the following five specific objectives:Add carbon transport module to SWAT+. SWAT+ currently has N, P and sediment transport modules. Although it has a C cycle in the soil, it lacks C transport processes in both subwatershed and streams.Improve forest ecosystem dynamics in SWAT+ following Yang and Zhang (2016).Improve representation of non-floodplain wetlands in SWAT+. We will follow the methodology of Evenson et al. (2016).Couple SWAT+ & WetQual models (SWAT+Wet). This requires modifications in WetQual processes and parameterization for improved compatibility between the two models.Validate the SWAT+Wet model in several wetland dominated watersheds.