Evaluation of watershed ecosystem health by using spatial modeling

The aim of this study is to identify healthy watersheds and characterize relative watershed health at the small watershed scale. Water balance for the watershed health assessment was investigated for Nakdong River Basin in South Korea using Soil and Water Assessment Tool (SWAT), which is a physically based hydrologic model. In order to predict the reliable available water quantity of the basin, the SWAT model was established by dividing the basin into 195 subbasins and the water resource facilities of 5 multi-purpose dams and 6 multi-function weirs were considered. The SWAT model was spatially calibrated (2005-2009) and validated (2010-2015) using daily observed water quantity data at the seven stations. For the calibrated model, patterns and simulations of hydrology will be evaluated by analyzing the hydrologic responses (infiltration, evapotranspiration, streamflow, percolation, soil moisture, baseflow, and groundwater recharge) and influences of blue-green water change. The watershed analysis will be carried out to assess the watershed health.