International Science and Technology Journal

This study aims to calculate the breach parameters and the maximum flow resulting from the hypothetical collapse of the Wadie Al-Qatara Dam, using two collapse approaches: overturning and seepage through the dam body. Based on the obtained results, the maximum rainfall intensity for a storm recurring every 1000 years in the watershed behind the dam is found to be 790.6 mm, causing surface runoff of 500 Bm3, with a peak time of 17.77 hr. The most severe scenarios for the collapse of the Wadie Al-Qatara Dam include overturning due to water accumulation behind it at a level of 236.2 m, resulting in a flow of 48.6x103m³/sec and taking 3.6 hr, for the collapse. The second most dangerous collapse approach from the seepage through the dam body at water level of 234.3m, causing a maximum flow of 29.6x103 m³/sec over a time of 3.52 hr. In both scenarios, a flood wave with a height ranging from 34 to 36 m, will be generated, heading directly towards the secondary dam and causing its destruction. Subsequently, the western part of Benghazi city will be submerged with water rising up to 3 m, leading to significant destruction and losses for the residents of those areas. In conclusion, recommend conducting studies for all possible dam collapse scenarios in Libya using modern technologies, developing a comprehensive emergency plan, installing flow and level measurement devices on watercourses, including dams, and rearranging the area within the boundaries of the Wadie Al- watershed. Additionally, a comprehensive evacuation plan should be developed to inform residents promptly in the event of a dam collapse, specifying evacuation routes and destinations. Keywords: Earth fill dam breach parameters, Maximum out flow Failure, Wadie Al-Qatara Dam.