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Dam breach or dam break causes release of large quantity of storage water from the reservoir creating major flood wave capable of causing disastrous damage to the downstream residents and property. The preparedness to withstand such an eventuality by predicting the possible extent of inundation of downstream zone and by formulating the emergency action plan can mitigate the disaster. The present study aims at predicting the characteristics of the flood wave such as peak flood stage, peak flood discharge and their times of occurrence and stage and discharge hydrographs at different locations downstream in the river due to Tehri dam-breach flood and also for monsoon flood. NWS-BREACH model is used for Tehri dam on the Ganga river, to predict the breach characteristics and the breach hydrograph. The predicted dam-breach flood hydrograph is routed through the Ganga river system using NWS-FLDWAV model, assuming that all the major tributaries joining the downstream Ganga river are already in flood stat...

The objective of the investigation, reported in this paper, is to study the effect of leakage through the sheet piles of a barrage on the uplift pressures on the barrage floor and the seepage underneath the barrage floor. Finite Element Method has been used to solve two dimensional Laplace Equation for appropriate boundary conditions to obtain the uplift pressures at the key points under the barrage floor for the impervious case as well as for various degrees of perviousness of the sheet piles. The results are presented as a function of KP/Ks, in which Kp is the permeability of the sheet piles and Ks is the permeability of the soil. KP/Ks = 1.0 corresponds to non existence of sheet piles and KP/Ks = 0 corresponds to impervious sheet piles. It has been found that the results for KP/Ks = 0.1 are drastically different from the results for KP/Ks = 0 and as KP/Ks changes from 0.1 to 0.5, the changes in the results are gradual.

The objective of this study is to develop and demonstrate the applicability of a computer code for flood routing in large tree type channel networks. The computer program is based on the implicit-finite difference algorithm recently developed by Nguyen and Kawano (1995). In this method, the system of simultaneous equations resulting from the finite-difference discretization is solved using an efficient double sweep algorithm specially designed for tree type channel networks. The computer code is applied to Ganga River Basin from Haridwar to Farakka barrage. The network consists of 29 channels with a combined length of 10,682 km. Flood routing is carried out with Log Pearson type III inflow hydrographs at the inlets of all the tributaries. The results are discussed in terms of the outflow hydrographs.