PERENCANAAN BENDUNG TIPE MERCU BULAT UNTUK MENDUKUNG DAERAH IRIGASI PEMATANG GUBERNUR KOTA BENGKULU

Abstract

Pematang Gubernur of Bengkulu city has good irrigation area, but since the last three years, 300 hectares of agricultural land is no longer cultivated because water demand for irrigation area is not up to the last rice terraces. It is caused by a weir not functioning optimally. This research aimed to plan the dimensions of the weir to be suitable to the nowadays condition of Pematang Gubernur’s hydrology. Hydraulic calculations done by using primary data and secondary data. The primary data used is the width of the river, the depth of the river, the river base elevation. Secondary data which achieved is network schmea. Apron floor calculation use lane method, meanwhille the calculation of weir head, stilling basin, intake gates, flushing gate and weir stability use mathematics equation. Discharge use on calculation is 37,29 m3/s with a return period of 100 years. The weir use rounded weir head with radius rounded head is 1,512 m and 1,68 m height. The effective width of the weir is 4,796 m. the stilling basin planned is the type vlughter with a length of 6,711 m. The length of the floor surface is 13,79 m. Width of intake gate dan flushing gate are 1 m with 1m in high. The design has passed the requirement of slide stability, shear stability, eccentricity stability and soil bearing capacity.