Analysis of water balance conditions as the impact of climate and land-use changes in Kapuas Watershed, Indonesia

Abstract

The Kapuas River is located in the West Kalimantan province and is the longest river in Indonesia. Climate change has an impact on the frequency and intensity of hydro-meteorological disasters. This study aims to analyze the spatial and temporal distribution of the water balance in the Kapuas watershed using the water balance equation. The data used is the monthly rainfall and evapotranspiration data for the years 1901–2019 from the CHIRPS and CRU data as well as the Kapuas watershed land cover data. Based on the study conducted, the Kapuas watershed experienced a significant increase in the dry month, but the trend of the magnitude of the dry month decreased but not significantly. The lowest average potential evapotranspiration occurred in DJF, which ranged from 2.8 to 3.2 mm / day, while the highest average potential evapotranspiration occurred in March-April-May (MAM), which ranged from 3.2 to 3.6 mm / day. The Kapuas watershed always experiences a water surplus, with the lowest water surplus occurring in July. Swamp forest in the southwestern and northeastern part of the Kapuas watershed has decreased in area, this is because the swamp forest has turned into agricultural land and plantations, so this condition has an effect on a significant increase in the incidence of dry months in the Kapuas watershed.