Karkhe River, in the above of hydrometer station of Paypol, passes from the middle of the hills and high grounds and enters in to the Khuzestan plain. Karkhe River, at the upstream of the dam axis, changes its direction about 90° and the dam lake is located at the right side of the axis. From the viewpoint of River slight steep, dam lake has a remarkable volume. The steep of reservoir is mild. Steep of the left abutment is too harsh but at the right side it became mild. In the left coast, at the distance of 200 Km to the dam axis, a relatively great flood channel enters into the river and in the downstream also there is a smaller flood channel that the dam power station is located in the left side of it. Besides, there is another flood channel in the upstream of the dam axis, on the right side.