THE ROLE OF PALEOMORPHO DYNAMIC OF THE KARKHEH RIVER IN SPATIAL STRUCTURE OF THE AZADEGAN PLAIN

One of the main characteristics of Azadegan plain in the west of Khuzestan province is active instability of geomorphic features of Karkheh River This instability caused extensive variations in the sedimentary setup in the western parts of this plain, such as buried and abandoned river beds, which are repeated over time. Therefore, these variations should be studied in more details in the upper Holocene, since they can help us to better understand the changes and sedimentation details to reduce the environmental hazards in the region. Morpho dynamic characteristics of this river in the flood plains of Khuzestan are influenced by the sedimentation conditions, climatic changes, and hydraulic base levels of the Persian Gulf and in this context the two dynamic river systems of Karoun and Karkheh in Khuzestan are very important to be studied in much detail (Ramesht, 22, 1382). These rivers have been changed the routes in the past in Khuzestan and consequently caused complex sedimentation systems. The morphologic characteristics of these rivers indicate their longitudinal profiles are higher than the main level of the flood plain of Khuzestan. The Karkheh River changed its route in Hamidieyeh position about 100 yrs ago and at the present is running by Sosangard City in Khuzestan. Diopin (2011) studied the routes of the Karkheh, Karoun and Jarhi Rivers in Khuzestan and he found a good correlation among these river dynamics and human developments in this province. He found four different routes for Karkheh River in his study. The objective of this study was to further lighten the route changes and dynamics of the Karkheh River which will help us to better manage the spatial settings and predict the environmental risk in the province.