SENSEflux-USGLB: Nitrogen and Phosphorus Loads, Sources and Pathways

SENSEflux-USGLB, the Spatially Explicit Nutrient Source Estimate and Flux for the United States Great Lakes Basin estimates total annual nitrogen and phosphorus loads from the US Great Lakes Basin to the coastline, as well as sources and pathways at 120 meter resolution for an average year during 2008 - 2015 period (ca. 2010). The SENSEflux model uses a GIS and mass balance approach to simulate nutrient fate and transport from point and nonpoint sources across the landscape through rivers to lakes and wetlands. It includes four components: (1) nutrient applications, (2) in situ losses, (3) basin attenuation through surface and subsurface pathways, and (4) stream and lake attenuation. This resource includes 120-meter maps of nitrogen and phosphorus loads, mass balance components (total applied nutrient, crop harvest, basin loss, river uptake, soil and groundwater storage), sources (atmospheric deposition, chemical agricultural fertilizer, chemical nonagricultural fertilizer, manure, septic tanks, nitrogen fixation from legumes, and point sources) and pathways (overland flow, tile drainage, groundwater, septic plumes, point) along with corresponding watershed summaries at the Hydrologic Unit Code 12 (HUC12) and HUC8 levels, as defined in the USGS 2014 Watershed Boundary Dataset. Sources are separated by subsurface (groundwater flow and septic plumes within groundwater) pathway and surface (overland and tile fields) pathway, so total nutrient delivery through a specific nutrient source can be computed as the sum of each source (i.e., gQAgComm + sQAgComm) through the pathways if applicable. Watershed summaries (kg/day) derived from those 120-meter maps (kg/day/cell) using the zonal statistics method with the 'SUM' function. SENSEflux-USGLB is described in full detail in the manuscript and supporting information of Wan et al. (2023) "Important Role of Overland Flows and Tile Field Pathways in Nutrient Transport in Environmental Science & Technology. https://doi.org/10.1021/acs.est.3c03741.