Analisis Pengaruh Perubahan Penggunaan Lahan Terhadap Debit Puncak Sub Das Kali Dengkeng Tahun 2010 Dan 2020

This research was conducted in the Kali Dengkeng sub-watershed which is one part of the Hulu Bengawan Solo watershed. The Kali Dengkeng sub-watershed is divided into three parts, namely upstream, middle and downstream. This study has two objectives, namely, to estimate the peak discharge of the Kali Dengkeng sub-watershed in 2010 and 2020 and to analyze the effect of land use changes on the peak discharge. This research method uses secondary data analysis method. The analysis used is in the form of the influence of land use changes on the peak discharge of the Kali Dengkeng sub-watershed in 2010 and 2020. Changes in land use that occurred between 2010 and 2020, namely forests decreased by 64.36 km2, settlements increased by 56.23 km2, swamps increased an area of 0.28 km2, rice fields decreased by 27.9 km2, open land increased by 3.14 km2 and dry fields increased by 32.86 km2. From the results of scoring using the cook method, the upstream sub-watershed has a runoff coefficient value of 31.525% in 2010 and 34.344% in 2020, the middle sub-watershed has a coefficient value of 37.429% in 2010 and 37.529% in 2020, the sub-watershed The downstream has a runoff coefficient value of 41.93% in 2010 and 42.652% in 2020. There is an effect of land use change on the increase in the runoff coefficient. The results of the calculation of the peak discharge in the upstream sub-watershed in 2010 amounted to 21.442 m3/second and the peak discharge in 2020 was 13.144 m3/second, the peak discharge in the middle part of the sub-watershed in 2010 was 29.491 m3/second and the peak discharge in 2020 was 24.628 m3/second. , the peak discharge of the downstream sub-watershed in 2010 was 25.203 m3/second and the peak discharge in 2020 was 15.291 m3/second. The increase in the runoff coefficient of 3.64 affects the increase in peak discharge of 4.767 m3/second if the rainfall intensity for each part of the sub-watershed based on the average rainfall intensity is 27.62 mm/hour. However, the intensity of rainfall, which tends to decrease in 2010-2020, has resulted in the estimated peak discharge amounting to a decrease of 23.07 m3/second