Development and Assessment of Watershed Management Indicators Using the Budyko Framework Parameter

This study aims to introduce the Budyko curve's parameter (w) as a watershed quality indicator and establish criteria. Basin-specific (w) was calculated in 183 watersheds based on land use in 2013. Weather data and runoff data were used, and runoff data were calculated using Hydrological Simulation Program-Fortran (HSPF). An estimation model was developed to estimate the w of the unmeasured watershed, and the R-2 of the developed model was 0.917, showing that the modeled value was reliable. A cluster analysis between basin-specific w and impervious area ratio in 2013 was performed to classify watershed quality. w was classified into four grades according to the dendrogram and impervious cover model. Watershed quality in 1975 and 2013 was evaluated using the developed indicators and criteria. The quality grades of 30 watersheds deteriorated, and the deteriorated watershed increased built-up and decreased forest and grass. To evaluate the indicators' applicability, the low impact development (LID) method was applied to HSPF to confirm the indicator and criteria changes. It showed that the watershed to which LID was applied has improved indicator and reduced grade. The indicator developed in this study is expected to be useful for watershed quality assessment and analysis of improvement effects according to watershed management.