Analisis Dimensi Dan Jumlah Sumur Resapan Untuk Optimasi Efektifitas Peresapan Aliran Permukaan (Run Off)

The ability of soil to infiltrate water has become very low as a result of land use changes, particularly when areas originally functioning as water infiltration zones are converted into built-up areas. The absence of infiltration areas causes rainfall to be directly discharged into local drainage channels, leading to an increase in surface runoff volume. This study focuses on Batu City, a tourism city that has experienced significant changes in land use. The main objective of this study is to calculate the volume of rainfall to be stored in relation to the development of a five-story building located in Batu City. In this research, the analysis of storage discharge is carried out using the SNI 03-2453-2002 method and the Nakayasu synthetic unit hydrograph method to obtain the maximum storage discharge. The results of the analysis using SNI 03-2453-2002 show that the maximum storage discharge for a 2-year return period is 46.208 m³, resulting in a requirement of 20 infiltration wells, and for a 5-year return period is 52.35 m³, with a requirement of 23 infiltration wells. Meanwhile, the analysis using the Nakayasu method yields a maximum storage discharge of 49.82 m³ for a 2-year return period, requiring 22 infiltration wells, and 56.44 m³ for a 5-year return period, requiring 24 infiltration wells. This study demonstrates that the selection of analytical method influences the estimated design storage discharge and, consequently, the number of infiltration wells required to control surface runoff in highly developed urban areas.