THE HARMIN RESERVOIR (IRAQ) COASTAL DYNAMICS

Abstract

The Hamrin reservoir, located on the Diyala River (left tributary of the Tiger River), differ for its unusual shape, large surface area and small depth, a significant level fl uctuations in the long-term dynamics and great depth of drawdown, and intense siltation. Intensive siltation of the reservoir caused by the arrival of material from solid river fl ow and from hollow (basin) slopes in which bottom reservoir is located. In rainy season the material moved through the temporary streams channels and deposited on alluvial fans at the foot of the slopes. In winter and spring seasons of reservoir’s full filling, at high water-level and under the process of wave increasing the various forms of underwater and above-water coastal forms of relief are developed. In dry summer season part of water area is dry out. Accumulative processes develop under low level of wave action; at that a big role belongs to soaking of sandy-clay material which composes the lower parts of the underwater coastal slopes. Drained part is involved in agricultural productivity. Annual renewal of the coastal relief induce the activity and abrasion-accumulation, anthropogenic double quick erosion and natural slope processes, so the rate of banks retreat is not reduced. Anthropogenicnatural reservoir system is still on the stage of activation, when stable relations between elements of new relief and environmental factors not yet formed, so the intensity of banks re-formation is not reduced, and siltation of the reservoir will be continued.