Application of the RSPARROW Modeling Tool to Estimate Total Nitrogen Sources to Streams and Evaluate Source Reduction Management Scenarios in the Grande River Basin, Brazil

Abstract

Large-domain hydrological models are increasingly needed to support water-resource assessment and management in large river basins. Here, we describe results for the first Brazilian application of the SPAtially Referenced Regression On Watershed attributes (SPARROW) model using a new open-source modeling and interactive decision support system tool (RSPARROW) to quantify the origin, flux, and fate of total nitrogen (TN) in two sub-basins of the Grande River Basin (GRB; 43,000 km2). Land under cultivation for sugar cane, urban land, and point source inputs from wastewater treatment plants was estimated to each contribute approximately 30% of the TN load at the outlet, with pasture land contributing about 10% of the load. Hypothetical assessments of wastewater treatment plant upgrades and the building of new facilities that could treat currently untreated urban runoff suggest that these management actions could potentially reduce loading at the outlet by as much as 20–25%. This study highlights the ability of SPARROW and the RSPARROW mapping tool to assist with the development and evaluation of management actions aimed at reducing nutrient pollution and eutrophication. The freely available RSPARROW modeling tool provides new opportunities to improve understanding of the sources, delivery, and transport of water-quality contaminants in watersheds throughout the world.

Effects of return flows on stream water quality and availability in the Upper Colorado, Delaware, and Illinois River Basins

“…The SPARROW tool has been used for a variety of water-resources applications. SPAR-ROW models have been developed to quantify and improve the understanding of long-term mean annual nutrient and (or) sediment sources, fate, and transport in many areas of the United States [46,[51][52][53][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70] and elsewhere [71][72][73][74]. SPARROW has also been used to model total dissolved solids [39,47] and total organic carbon [75].…”

Ammonium Nitrogen Streamflow Transport Modelling and Spatial Analysis in Two Chinese Basins

“…Hybrid empirical and mechanistic models based on regression, such as the SPARROW model, can be used to conduct studies at different spatial scales on nutrient transport with smaller input datasets, such as data on nutrient load, nutrient sources, and landscape properties. Since it was first established by the U.S. Geological Survey (USGS) [13], SPARROW has been extensively applied in North America [14][15][16][17][18][19][20][21][22][23][24], Asia [25][26][27][28][29][30], New Zealand [31,32], Spain [33,34], and Brazil [35] with satisfactory performance. SPARROW has been employed in studies on regions of various sizes, from 153 km 2 [36] to 3.2 million km 2 [37].…”