ANALISIS PERKIRAAN DEBIT ALIRAN PADA DAERAH ALIRAN SUNGAI UNDA BERBASIS SISTEM INFORMASI GEOGRAFIS (SIG)

Abstract

The limited flow data is an obstacle that often occurs in the analysis of water availability. To obtain this data, nowadays there are many prediction models for flow discharge. Remote sensing technology can improve the development of conventional rainfall–runoff relationship model studies. With this technology, it can help predict the runoff discharge for each Sub-watershed. The Unda watershed is one of the potential watersheds in the province of Bali. The flow discharge analysis was carried out using the overlay method by overlaying the land use map and the soil type map in the Unda watershed so as to obtain the CN value, then proceed with calculating the predicted flow rate using the SSCN method. From the analysis in the last ten years there have been fluctuations in discharge, where the largest discharge ever occurred was 10,569 m3/s in 2013 in the Telagawaja sub-watershed and the lowest was 0.079 m3/s in the Tanah sub-watershed in 2010. For the Telagawaja sub-watershed in the last ten years the average discharge -the average is 8.068 m3/s, Masin sub-watershed 0.963 m3/s, Tanah sub-watershed 0.163 m3/s, Nyuling sub-watershed 0.705 m3/s, Kaun sub-watershed 1.653 m3/s, Yeh Batah sub-watershed 0.564 m3/s Unda is 1.722 m3/s, and Sangsang sub-basin is 0.764 m3/s.