Hydrological and Hydraulic Analysis of Wanggar River Flow

Abstract

Rivers are one of the natural resources to be utilized for human life, including the provision of irrigation water, raw water, industry, transportation and others. Rivers can cause problems if the flow exceeds the capacity of the river. Therefore, in this study, hydrological and hydraulic analysis was carried out on the Wanggar River to determine the hydraulic capacity and the possibility of flooding. This research has two important parts, namely hydrological analysis and hydraulic analysis. Hydrological analysis has two sub-sections, namely the planned rainfall and discharge analysis. The planned rainfall is calculated by various distribution methods, namely Gumbel, Normal, Log Normal, and Log Pearson III distributions. Furthermore, testing was carried out using the statistical parameter method, Chi Square and Smirnov-Kolommogrov. The calculation results show that the frequency analysis that passes the three tests is Log Pearson III. The results of the Pearson Log III were then calculated using the ITB-1, ITB2, Snyder and Nakayasu methods. Then the result of the discharge plan is chosen which is closest to the Creager graph. The calculation result of 100 year flood discharge is 2,169 m3/s. Hydraulic analysis is carried out by finding the velocity of the critical shear stress and the critical shear stress. The critical shear velocity obtained by the Scobey method is 0.93 m/s and the critical shear stress is obtained by the Shield method of 9.49 N/m2.