Dam Breach Analysis and Damage Assessment of Nova Kakhovka Dam using Satellite data and 1D and 2D Hydrodynamic Modeling

Abstract. A dam is a man-made structure that crosses a river or other body of water intending to hold water and create a reservoir. When a dam fails, it results in the loss of lives and economic devastation, which directly depends on factors like water depth, velocity, warning time, and the presence of people in the affected area. Dam failure necessitates the use of dam-break modeling, which evaluates the flood characteristics such as the discharge and timing of flood waves resulting from the dam's breach. This study focuses on examining the two breach scenarios of the Kakhovka dam located in Ukraine. The analysis utilized the HEC-RAS software, a widely recognized tool for hydraulic modeling. Multiple breach parameters, including breach width, breach depth, and breach time, were considered to evaluate their impact on downstream flooding. The model is utilized to assess the potential outcomes of a dam break in downstream areas, including factors such as water level rise, travel time of flood waves, flow velocity, and other parameters. The resulting flood plain was also mapped using GIS tools to show the extent of flooding. Damage assessment for the downstream area was also done by using remote sensing based LULC. The study estimated 35962 m³/sec of peak discharge from the 300-meter dam breach scenario and the flood extent (823 km²) from this scenario also matched with the actual situation as observed by remote sensing data. These estimations help in understanding and managing the risks associated with structural failures.