An interdisciplinary swat ecohydrological model to define catchment-scale hydrologic partitioning

Abstract

Land use and climate change have long been implicated in modifying ecosystem services,such as water quality and water yield, biodiversity, and agricultural production.To account for future effects on ecosystem services, the integration of physical, biological,economic, and social data over several scales must be implemented to assess theeffects on natural resource availability and use. Our objective is to assess the capabilityof the SWAT model to capture short-duration monsoonal rainfall-runoff processesin complex mountainous terrain under rapid, event-driven processes in a monsoonalenvironment. To accomplish this, we developed a unique quality-control gap-filling algorithm for interpolation of high frequency meteorological data. We used a novel multilocation,multi-optimization calibration technique to improve estimations of catchmentwidehydrologic partitioning. We calibrated the interdisciplinary model to a combinationof statistical, hydrologic, and plant growth metrics. In addition, we used multiple locationsof different drainage area, aspect, elevation, and geologic substrata distributedthroughout the catchment. Results indicate scale-dependent sensitivity of hydrologicpartitioning and substantial influence of engineered features. While our model accuratelyreproduced observed discharge variability, the addition of hydrologic and plantgrowth objective functions identified the importance of culverts in catchment-wide flowdistribution. The results of this study provide a valuable resource to describe landscapecontrols and their implication on discharge, sediment transport, and nutrient loading.This study also shows the challenges of applying the SWAT model to complex terrainand extreme environments. By incorporating anthropogenic features into modeling scenarios,we can greatly