Development of Strategy for SWAT Hydrologic Modeling in Data-Scarce Regions of Peru

Abstract

In this study, methods were developed to create and evaluate the performance of the Soil and Water Assessment Tool (SWAT) in southern Peru where commonly used input data sources were not available. Soil classes were defined based on regional soil taxonomy and suitability maps combined with soil profiles. Local land cover and remotely sensed satellite data were used to develop a land cover database. Water balance analysis of the reservoir as well as satellite evapotranspiration data were used for model performance assessment. Results showed that these strategies provided reliable predictions of hydrology in this region, with the uncertainty quantified based on the range of inputs. Overall, this semiarid watershed was base flow driven and average annual surface runoff contribution to streamflow was less than 9%. Assessment of water pathways and their uncertainties based on the uncertainty of estimated inputs also showed that 62% of precipitation was removed by evapotranspiration with up to 16% uncertainty. The methods introduced in this study can be applied to other data-scarce watersheds, and findings provide insights on the hydrology of the Peruvian Andes region.