Spatial dynamic model of land use land cover change on hydrological response characteristics in the Upper Ciliwung Sub-Watershed

Abstract

Ciliwung Watershed is one whose state is critical. This condition causes the expansion of residential areas upstream of Ciliwung. Land use and land cover change affect a region’s hydrological characteristics. As a hydrological model, the SWAT (Soil and Water Assessment Tools) can predict the hydrological watershed characteristics affected by land use. This study aims to assess the land use change influence on hydrological characteristics and variations in inflow and outflow to develop the ideal recommendations for land use in the Ciliwung sub-watershed using system dynamics. The main river channel is constructed based on the watershed delineation process results, the watershed boundary consisting of 27 sub-watersheds. Due to average monthly discharge, the impact of land use change on hydrological characteristics in 2011, 2016, and 2020 were 65.01, 63.59, and 64.31 m3/second, respectively. The hydrological characteristics of all HRUs generated revealed that the Q max was 13,09 m3/s, and the Q min was 0.18 m3/s. In upstream Ciliwung, based on an inflows and outflows analysis, there were variations in 2011-2016 and 2016-2020. Based on the calibrated simulation results, the coefficient of determination (R2) was 0.8, and NSE was 0.78. The resulting R2 and NSE values indicate excellent model performance in the validation results. The ideal scenario is the intervention scenario on land use and population demography since it can reduce runoff. Runoff is the water that flows over the surface because the soil has reached its maximum infiltration capacity.