Dam Break Flood Inundation Modeling for Mount Coffee Dam

Abstract

Dam break analysis is crucial for investigating future effects posed to human life and property by a sudden release of water to the inundation area of a dam.Every constructed as well as proposed dams need to be analyze for the possibility of dam break because even with advanced technology,failure cannot be rooted out based on the huge level risks associated with it.This study aims at establishing the worst-case scenario at the Mt.Coffee dam as a result of overtopping.The impacts are determined using numerical 1-dimensional software (MIKE 11).The flood condition is prompted by the Probable Maximum Flood (PMF) of the basin which is inputted as a time dependent external boundary condition into the reservoir.Accuracy in this study is vital to instituting foundation for further investigations on Emergency Action Plan and Risk Management among others.Efficient dam break analysis relies on high precision of breach parameter.To arrive at this result,two widely used and well recommended breach prediction parameter methods are used in this research.The Federal Energy Regulatory Committee (FERC) and Froelich-2008 regression breach prediction methods are compared to yield outflow hydrographs,travel time of flood from the onset of the overtop to downstream locations,travel time from peak outflow to inhabited locations downstream,velocity of flood,water levels,and attenuation in discharge downstream of the dam break.The sensitivity of the breach is also tested by interchanging prediction parameters such as breach width,breach formation time,and breach slope channel.By establishing the inflow design flood,it has been proven that the Mount Coffee dam has a high possibility of failure due to the inadequacy of spillway capacity.