Kajian Perubahan Muka Air Pada Saluran Bendung MoyanKabupaten Musi Rawas Provinsi Sumatera Selatan

Abstract

The Deras II Irrigation Area covering an area of 928 hectares has 2 (two) permanent weirs as a source of irrigation water, namely the Moyan weir and the Aur weir built in 1984/1985 and 1987/1988. Administratively, this irrigation area covers the area of Sumber Hartadistrict. The water source for the Moyan weir comes from the Deras River. At first, the upstream part of the Moyan Weir contained idle land in the form of a swamp, at this time the swamp was used again by farmers to become rice fields whose water source came from the river (upstream Weir Moyan). With this water withdrawal, it has an impact on the flow of water entering the Moyan intake to be reduced, therefore it is necessary to conduct a study of discharge that can be used by farmers at the upstream of the weir so that the water supply at the Moyan intake willdroping of water. For the regulation of the water, the Deras II (Moyan Weir) Irrigation Area of water use management activities are carried out.The simulation results with the HEC-RAS program at the station in the channel reviewed downstream of the Moyan weir with an existing discharge of 0.024 m3/second, it can be seen that the water level rises only as high as 8 cm, there is no significant increase in water level in the Moyan weir channel, so it can be said that there is no overflow in the downstream channel of the Moyan weir.While the simulation results with a discharge of 1.413 m3/second with a return period of 5 years (R5), the condition of the upstream channel of the Moyan weir has a significant increase in water level of 75 cm, but the increase in water level is not significant enough in the Moyan weir channel, so it can be said that there is no overflow in the upstream channel of the Moyan weir.