A software library for quantifying regional-scale nitrogen transport within river basin systems

A software library for quantifying nitrogen fate and transport at the regional-scale is presented as a tool for managing river basin systems. The tool is based on the United States Geological Survey (USGS) SPAtially Referenced Regression on Watershed attributes (SPARROW) model and implements the prediction portion of SPARROW to quantify overland and in-stream losses of nitrogen within a river basin system. The intention of the software library is to serve as an Application Programmers Interface (API) that can be used to construct analysis and visualization tools that address a variety of management scenarios. By leveraging the API along with other existing open source and freely available software libraries for visualization, numerical methods, and network algorithms, it is possible to produce decision support tools that relate pollution sources to downstream loadings. These tools can be used by water resource managers to understand how hypothetical regional-scale changes to the landscape (e.g. land use change) might impact water quality conditions. The use of the model API is demonstrated with a case study that addresses three potential management questions regarding nitrogen fate and transport in the Upper Neuse River Basin of North Carolina.