PERENCANAAN ULANG BANGUNAN PELIMPAH (SPILLWAY) PADA BENDUNGAN BAGONG KABUPATEN TRENGGALEK

Abstract

Bagong Dam is a rock-fill type dam that was built for flood control in Trenggalek district and as a reservoir for irrigation water during the dry season. In this calculation, it is found that the flood discharge tracking analysis is Q100 = 164.742 m3/second, Q1000 = 182.419 m3/second, and QPMF = 394.425 m3/second, with water elevation above the crest +328.67 meters. This spillway is designed with a overflow spillway type which includes from the launch channel, and the energy reducer channel using a USBR type III stilling pool. With the results of the channel analysis the maximum water level occurs at the QPMF return period of 2, 355 meters with a maximum flow speed of 22.78 m2/second and a froude value at the end of the channel of 7.126. Analysis The stability of the spillway is controlled using overturning control, shear control, and control of the bearing capacity of the soil, all of which are safe for spillway structures. Furthermore, for the reinforcement of the walls and floor of the channel using the highest wall, namely the energy absorber wall as high as 8 meters and on the channel wall the amount of reinforcement D13-200 is obtained which is controlled in an empty and flooded channel. As for the floor of the channel of reinforcement D13-300 are assumed to be in a flooded state. The construction cost for the construction of the spillway is Rp. 241.483.929.346.