Reservoir storage simulation of Sepaku Semoi Dam Penajam Paser Utara Regancy

Abstract. The Sepaku Semoi Dam is located in East Kalimantan Province. This dam aims to supply raw water supply for the IKN area, North Penajam Paser Regency, and Balikpapan City. Population growth and the Government's plan to move the Country’s Capital City to East Kalimantan Province encourage the high demand for raw water, so that in fulfillment it requires the construction of dams. In addition to being able to supply water continuously, the dam must also be safe from failure due to overtopping. The rainfall used is from the Tropical Rainfall Measuring Mission satellite, with the design flood discharge using the Nakayasu Synthetic Unit Hydrograph method. The mainstay discharge comes from BWS Kalimantan IV. The results of flood routing of the Sepaku Semoi Dam do not have the potential for overtopping with the highest elevation Q1000 + 23.636 m and QPMF + 24.475 m. The need for raw water in the short-term projection is 1.55 m3/s medium term 3.60 m3/s and long term 4.94 m3/s. From the reservoir storage simulation, the largest outflow discharge was obtained with a short-term raw water demand of 2,330,433 m3/0.5 months, a medium-term of 5,164,353 m3/0.5 months, and a long-term of 7,001,073 m3/0.5 months. With this, the highest reliability opportunity in the simulation of short-term raw water needs is 100%, the highest failure is 0%, the medium-term highest reliability is 100%, the highest failure is 92%, and the long-term highest reliability is 71%, the highest failure is 100%.