Analisis Efektivitas Waduk Ciawi Menggunakan Model SWAT Sebagai Upaya Pengendalian Banjir DAS Ciliwung

Abstract

Management of the upstream watershed was significant factor because it had a role as the water catchment area to decrease the surface flow and potential flood. Ciliwung watershed had been gaining attention because the Indonesia central government, which is Jakarta, was located in the downstream of that watershed frequently flooded. The Ciawi Reservoir construction program on the upstream watershed was expected could help to recover that issue. The aim of this research was to analyse the effectiveness of Ciawi Reservoir by hydrology response that obtained by apply the SWAT model. The scenario of reservoir modelling was made on the hydrology simulation that had been formed, so the alteration of hydrology response that happened before and after the reservoir model applied could be known. There were 28 subbasins and 516 HRUs with 9 types of landuse, 3 soil types, and 5 slope classes on Sub Ciliwung Hulu watershed. The reservoir modelling with 15 scenarios indicated the alteration of flow discharge that specifically observed on outlet point 1 (Katulampa). The highest total discharge derivation was 158.626 m3 s-1 (34%), while the highest peak discharge derivation was 27.07 m3 s-1 (47.79%), and the best KRS value was 28.326 with good category. Based on the obtained result, the scenario of reservoir modelling managed to minimize the flow rate, so it could be said that the construction of Ciawi Reservoir was considered effective enough.