Author(s): Tawatchai Tingsanchali; Williams M. Putuhena
Linked Author(s): Tawatchai Tingsanchali
Keywords: No Keywords
Abstract: The flood flow conditions in the Cimanuk river and its Kertasemaya flood plain as a result of an assumed sudden breaching of a river dike are determined by using two mathematical models. The first mathematical model is aone dimensional (1-D) model used to compute the flood flow condition along the 100.6 km reach of the Cimanuk river from Rentang weir to the river mouth at Java sea. The 1-D model utilizes the Saint Ven ant equations and the node and branch computation technique. The outflow through the breached dike section is computed by using a free flow weir equation and is used as the upstream input to the second model which is a two-dimensional (2-D) fl ood plain model. The 2-D model computes the flood depths, velocities and spreading of inundated area over the flood plain. The 1-D river flow model is calibrated using the river flood data in April and May 1981 and January and Mar ch 1985 and verified with the data in January and M arch 1986. The Manning n of the 1-D model is found to be from 0.025 to 0.032. For the 2-D model, the Manning n value of 0.05 is recommended based on the ground and vegetation conditions in the flood plain. Both models are app lied to compute flood flow in the river and its flood plain under a given flood condition of 50year return period. Sensitivity analyses have been carried out to determine the effects of Manning n on the computed results.
Year: 1991