Hydrological dynamics of surface waters in the Pire River microbasin, using Soil and Water Assessment Tool (SWAT)

Abstract

The Pire river microbasin is located in the Central American dry corridor, belonging to one of the twelve subbasins of the municipality of Condega. The area under study has an area of 109 km2 and houses about 8,900 inhabitants; it is considered as the most densely populated area in the municipality. 70% of the territory in the micro-basin has a forest vocation and the remaining 30% corresponds to agriculture. In 2015, the Nicaraguan Institute for Territorial Studies (INETER) shows that thickets represent 50% of the total territory, grasslands (37.6%), annual cultivation (7.43%), latifoliate forest (4.7%) and populated center (0.27%), showing that the soils are not being used according to their vocation. To assess the influence of land use on surface water hydrological dynamics, the water and soil assessment tool (SWAT) was used; developed and tested by the ARS (USDA) for hydrological simulation and prediction of soil-related processes; 55 hydrological response units (HURs) were obtained on which water production, sediments, overflow were estimated. The highest generation HURs of sediments and overflow are located in Ultisol soils covered by thickets on slopes greater than 500 meters.