Analysis of immersed geological formations for Bekhmeh dam reservoir/ Erbil

Geological formations areas measurements for immersion level have been got for the Bekhmeh dam reservoir depending on the digital elevation model (DEM) with resolution (10 m) and Global Mapper-GIS software, which deal with the spatial analysis and get the spatial data of the landforms. The immersed area of each geological formation was determined separately for all levels, from the minimum level (380m) to the maximum one (600m) above the sea level, with (1 m) interval According to these measurements, Aqra-Bekhme and Shiranish formations have the highest value of the immersed areas, with immersion area (46386) m2 and (33183) m2, respectively, which form (19.6%) and (14.01%) respectively of the total immersed area of the reservoir. These two formations were immersed at most of the immersion levels. Those formations consist of hard rocks with low solubility.The lowest value of the immersed area was for (Naopardan and Chile Formation) with an area (79) m2, which forms (0.03%) of the total immersed area; followed by Chia Gara, Barsarin, and Nokelekan formations with an immersed area of (164) m2, which form (0.07%) of the total immersed area .Those formations were immersed at the last three immersion levels (570-600m). The soluble and friable unit, which cause an engineering problems, has low value of the immersed area. That unit represented by Fat'ha Formation, which has an immersed area of (16399) m2, and forms (6.92 %) of the total immersed area. In addition, it is far away from the dam body with (1472) m. These characteristics qualifies this location for reconstruction the dam.