Dam-Break Flood in a Natural Channel: A Case Study, Aslantas Dam

Authors: Nuri MERZİ, Nurünnisa USUL, Mustafa MOLU

Abstract: Although dams are very safe structures, they can fail. Since they store a tremendous amount of water in their reservoirs, failure of a dam generally results in an unforgettable disaster. Therefore, inundation maps with different dam failure scenarios should be obtained. To obtain these maps, computer models simulating these events, both for breaching of the dam and routing of the flow through the downstream reach, can be used. Solution methodologies were presented for a dam-break case for Aslantas Dam on the Ceyhan River by using one of the well known dam-break models, DAMBRK. The spillway capacity of Aslantas Dam was found to be safe for an overtopping failure in the presence of a probable maximum flood (PMF). In computations for the piping failure case, i.e., dam breaching occurring initially at the two thirds level of the dam's height, the outflow hydrograph through the breaching dam attained a peak value of 47 999 m3/s. Levees protecting the Ceyhan Plain were found to be safe for the overtopping scenario in the presence of PMF. On the other hand, levees were found to be insufficient for the piping case.

Keywords: Dam-break, breach, reservoir routing, hydraulic routing, piping , DAMBRK, Aslantas Dam, Ceyhan River.