FLOOD CONTROL ANALYSIS OF BATANG BANGKO RIVER, SOUTH SOLOK DISTRICT

Batang Bangko, South Solok Regency has a river with a length of 11.90 km. Batang Bangko is a flood-prone area, especially the Koto Baru area of Sungai Pagu Subdistrict, due to the dense population living in the Batang Bangko edge area which causes the absence of infiltration reservoirs. In planning the dimensions of Batang Bangko, an average rainfall calculation is carried out using the average method of 2 [two] rainfall stations, namely the muara labuh rain station and the padang aro station. This study aims to determine the amount of discharge that occurs in Batang Bangko, planning the arrangement of the river by normalising the river, and planning the dimensions of the river in analysing the flood water level. The type of research carried out is the calculation of the 10 [twenty] annual rainfall plan using the average of the Normal Distribution method, the Log Normal method, the Log Person III method and the Gumbel method. In planning the normalisation of Batang Bangko River through literature study, data collection, hydrological analysis and hydraulics analysis. And for the calculation of discharge plans used Hasper and Rational methods. The results of the two methods concluded that the flood discharge used was the Rational method with a return period of 10 years, namely (Q10) 31.39 m3 / sec.The river cross section is trapezoidal. For the trapezoidal cross section, the base width is 15 metres, the top width is 37.02 metres with a height of 3.61 metres with a slope of 45°.