INFLUENCE OF LAND USE CHANGE ON THE MAGNITUDE OF THE RUNOFF COEFFICIENT IN THE UPPER KAPUAS RIVER BASIN

The increase in population in the upper Kapuas Hulu River Basin will also increase the need for land. This increase in land demand can cause land use changes, affecting the runoff coefficient. Based on the reasons above, research was conducted to determine the effect of changes in land use on the magnitude of the runoff coefficient in the upstream part of the Kapuas River Basin from 2012 to 2017 and 2017 to 2022.The runoff coefficient calculation uses the U.S. Forest Service, Hassing, Kodoatie, and Syarief methods. Each method uses different parameters to determine the results. Data processing is carried out using a Geographic Information System (GIS).The analysis and calculations show that the runoff coefficient values obtained in the Upper Kapuas River Basin using the U.S. Forest Service method in 2012, 2017, and 2022 are 0,133, 0,136, and 0,145. The Hassing method results are 0,308, 0,309, and 0,312, and the Kodoatie and Syarief method results are 0,156, 0,167, and 0,173. This value shows that the Upper Kapuas River Basin is in reasonably good condition because the runoff coefficient value is far below 1.