Evaluation of Geomorphology Maps Efficiency in Site Selection FloodWater Spreading Suitable Areas in Ivar Watershed

Iranian due to the special geographical position, topography and climate, among arid regions of the world.Water is the limiting factor in the areas of human activity. Major part areas of human activity, development of renewable natural resources, agriculture, industry and urban development concentrated on quaternary deposits. Floodwater spreading in addition to preventing erosion and flood damage, caused economic prosperity of these areas. Determine the floodwater spreading appropriate place is required to full understanding of distribution location characteristics like infiltration, slope, thickness of alluvium, percolation coefficient. In this study was investigated the relationship between ivar Watershed geomorphological units and floodwater spreading the appropriate regions. Thus, the region Geomorphological map were provided using aerial photographs interpreting, satellite images and topographic maps. To geomorphological map evaluation, this map of floodwater spreading prone areas based on main criteria four, sub criteria eight and index twenty-four selection and using decision support systems was obtained in ivar compared and accordance with a talent were defined for floodwater spreading geomorphology work units.The results showed that all the land in the foothills of the units are in a class very poor and poor. Fans lands in alluvial geomorphology units with percent 20.7 and the average area of the new and old alluvial units are located with percent 34.5. As a result, new, old alluvial terraces and alluvial fans the most percent overlap are allocated for flood water spreading prone areas. More flood water spreading prone areas have been the quaternary units Qt1, Qt2, Qf1 and Qa1 the cause of it can be positioned units in the margins of areas main channel the consist this units of clay, silt, sand and gravel and putting these units areas at lower altitudes and in low slopes mention. According to easily geomorphologic maps in areas lacking information sub surface, geomorphological maps can be used as a suitable criterion for determining the floodwater spreading regions in areas information lacking.