Water Resources Role in Location of Achaemenid Settlements in the Sistan Plain

For a long time, the Sistan Plain has been one of the important areas for men’s settlement due to abundant of water resources. However, this relation between water resources and settlements has not been comprehensively studied so far. Hence, the present survey aims to study the reciprocal relation between the Achaemenid settlements and natural environment in areas specially based on water component. The research has been carried out through the descriptive-analytical and historical method using GIS software. To reach the research goals after checking the environmental conditions, six variables including water resources types, distance from water resources, land slope, soil type, geology and settlements area were studied and the obtained results indicated the effective role of the surface water resources in settlement placement and extents. The presence of water resources, gentle land slopes and consequently ease of water flow down to the different areas of the plain, the potential to build branching canals to keep the suitable distance from the river which are the characteristics of alluvial fans, as well as settlement on the alluvial terrace to avoid flood hazards are among the factors which turned the area into population absorbing center despite the absence of aquifers and heavy dependence on surface water resources.