Reducing the Susceptibility of Flood Supplier Areas in Gondang Micro-Catchment, Bojonegoro, East Java Province: a Flood Disaster Mitigation Effort

Abstract

Abstract Flood disaster mitigation begins with reducing the susceptibility of flood supplier areas. This task can be accomplished by mapping the flood-supplier susceptibility and then deciding on long-term flood mitigation actions following the susceptibility level of the land and the legal status of its area. Pacal reservoir has Gondang as one of its catchment areas. During the rainy season, the spillway releases water immediately because the inflow exceeds capacity. To maximize water storage, reduce Pacal reservoir input, and prevent downstream flooding, the land cover must be improved. This paper will investigate the Gondang micro-flood-prone catchment’s locations and propose mitigation strategies. The legal status of the land is used, as well as Climate Hazards Group Infrared Precipitation with Station data (CHIRPS), Digital Elevation Model (DEM), and Google Imagery from 2014 and 2020. Paimin’s Equation was used to assess the flood risk. The findings indicate that the Gondang micro-catchment is susceptible to flood suppliers on a low to a high level. Changes in land cover during 2014-2020 resulted in alterations to the susceptibility level of the area. The legal status of the area has had an impact on land cover management. The simulation results of reforestation and maintenance of dense forests in forest areas, as well as regreening activities in agricultural areas, can improve land with high susceptibility to moderate levels, which accounts for 20.9% of micro-catchment areas. All of these proposed activities are expected to control the Pacal Reservoir’s inflow during the rainy season by increasing soil infiltration and reducing runoff.