Analisis Debit Andalan DAS Tanggul untuk Kebutuhan Air Minum Berdasarkan Pemodelan Hujan Limpasan Menggunakan Software HEC HMS

Abstract

The research was conducted in the DAS Tanggul which passes through 6 districts namely Sumberbaru, Tanggol, Jombang, Umbulsari, Kencong and Semboro. Data processing begins with rainfall consistency test using RAPS or Rescaled Adsjusted Partial Sums method and then calculates the average rainfall of Tanggul DAS using the Polyghon Thiesen method. Rainfall runoff modeling using HEC HMS is carried out using the SCS CN method. Calibration is carried out by comparing the observation discharge in 2020 with modeling data in 2020. The calibration results showed NSE value of 0.56 and R2 of 0.53. Validation result using data in 2021 showed NSE 0,56 and R2 0,725. Maninstay discharge (Q90) is calculated using the weibull method which refers to the SNI 2015. Discharge with a probability ratio of 100% on Tanggul DAS is 1.70 m3/s and discharge with probability ratio of 90% (Q90) is 3.72 m3/s. Based on the results of the calculation of water needs in Sumberbaru, Tanggul, Kencong, Umbulsari, Jombang and Semboro obtained the average water requirement in 2043 for 6 district water requirements is 0.955 m3/s so that DAS Tangkul can be recommended as one of the alternative sources of raw water to meet water needs.