KAJIAN DEBIT BANJIR DAN TINJAUAN TERHADAP KEHANDALAN KAPASITAS ALUR ALAMI SUNGAI AESESA KABUPATEN NGADA PROPINSI NUSA TENGGARA TIMUR

• Main Author: Leda, Alexander
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/5386
• Institution: Institut Teknologi Bandung

<b>Abstract:<p align="justify"> <br /> <br /> Aesesa River has a very ideal potential to be developed as a water source for either have irrigation agriculture area or its other potential like dry farming area, husbandry and fishery. The main problem on Aesesa River is often of flood taken place, so it is need to be analyzed both flood discharge and reliability of river cannel capacity.<p align="justify"> <br /> <br /> <br /> The study was done in this research concerning a flood discharge based on rain data with Snyder Hydrograph and Nakayasu Hydrograph method. The analysis of River natural channel capacity by using HEC-RAS software and its capacity reliability toward flood discharge load, analysis with concept of a Safety Factor (level-1) and Second moment analysis (level-2) <br /> <br /> Flood discharge analysis with Snyder's method resulted design flood as follows : two-year-return-period (Q2) = 1,206 m3/second, five-year-return-period (Q5) = 1,346 m3/second, ten-year-return-period (Q 10) = 1,426 m3/second, twenty-year-return-period (Q2o) = 1,495 m3/second, fifty-year-return-period (Q50) = 1,577 m3/second and one hundred-year-return-period (Qioo) = 1,636 m3/second.<p align="justify"> <br /> <br /> <br /> The HEC-RAS model simulation result, with Q2 up to Q20 Input, toward twentieth of cross-section on Aesesa river, conclusion that river joints segment in upstream in Alorongga Village has not experienced over bank. While on downstream in Nila Village as long as 1.90 km was identified over bank. On two-year-return-period (Q2) =1,206 m3/second, some cross-section were still capable of accommodating flood discharge but for the twenty-year-return-period (Q20) =1,495 m3/second, chanel capacity of downstream segment in Nila Village was not longer capable of accommodating flood recharge. Minimum bank full capacity = 1,186 m3/second on cross-section 6 and maksimum = 1,478 m3/second on cross-section 6<p align="justify"> <br /> <br /> <br /> Toward load Q20 =1,495 m3/second , the existing capacity reliability on Aesesa river natural channel with Second moment analysis method (level-2) for normal distribution probability is 39.82 %, and risk of failure (overbank) is 60.18%.<p align="justify"> <br /> <br /> <br /> For short term, the flood control conducted with embankment while long term can be build a dam for reduced the flood peak, also able to supply the raw water for its other need. Flood control strategy with embankment can increased reliability from 39.82% to 95.15% and risk of failure decreased from 60.18% to 4.85%. <br /> <br /> <br />