DESIGN ANALYSIS OF FILLING VOID D2 WITH BINUNGAN RIVER WATER AT PT BERAU COAL KALIMANTAN TIMUR

• Main Author: Hasanah, Sarah
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/71522
• Institution: Institut Teknologi Bandung

the activity will leave voids. Environmental issue in void are common in the quality of post-mining lake water which contain acid. Management of pit lakes is needed to meet environmental quality standards by accelerating the period of acid oxidation in rocks. One of the option is to put river water into the void so that can speed up void D2 filling. Binungan site D2 voids are filled using Binungan river water during flood conditions. The watershed chosen to fill the void must know the flood characteristics by calculating the flood event from the rainfall data analysis. By using BMO1 station rainfall data for the period 2005-2021, a Gumbell distribution plan rainfall of 83.08 mm was obtained, which resulted in a plan rainfall intensity of 11.43 mm/hour. The topography and land use data of the Binungan watershed resulted in a catchment area of 136 km2 and a river length of 35 km. Binungan watershed land characteristics are secondary dry forest with a slope of 0.04%. Then the results of rainfall intensity and watershed area will be obtained synthetic unit hydrograph soil conservation service (SCS). After that, a simulation of the calculation model was carried out with HEC RAS software to obtain the relationship between the discharge and the water level in the cross section of the canal at various channel dimensions with water inflow level at +4 and +5 masl. By analyzing rainfall data, it was found that flood events ranged from 30-120 days at return periods of 2, 5, and 10 years with the peak water level at RS4000 during floods at elevation +6 masl. The option of filling void D2 from the Binungan River can be carried out at the level of +4 masl at RS4000 east of void D2 with the dimensions of the channel bottom width of 3.5-4 meters for one year with many events 30 times from rainfall intensity.