Evaluasi Kapasitas Sungai Haruyan Hilir Kabupaten Hulu Sungai Tengah Provinsi Kalimantan Selatan dengan Menggunakan HEC-RAS 5.0.3

Abstract

The Haruyan Hilir watershed has an area of 94.41 km2 with a river length of 35.24 km and most of the river basin is forest. The Haruyan Hilir River crosses the Tabudarat Hulu Village, Hulu Sungai Tengah Regency, South Kalimantan. The river border is very densely populated and the Haruyan River is a river that often runs out during the rainy season. This situation is very detrimental to the people who live in the area around the Haruyan Hilir River . There is a need to analyze the existing capacity of the river to find out how high the flooding is .Flow profile analysis is carried out with the application of HEC-RAS 5.0.3, while to analyze the design flood discharge using the synthetic unit hydrograph Nakayasu. The design of the Haruyan Hilir River flood discharge uses a design flood of 2 years return period = 267,100 m3 / sec, 10 years return period = 400,401 m3 / sec, and 20 years return period = 437,188 m3 / sec. In the existing condition at the return of 2 years found 55 overflowing cross-section stakes. With these conditions, it proves that the Haruyan Hilir River is a river that is always flooded during the rainy season.