The Effect of the Development of New Irrigation Systems to Watertable Changes Using System Dynamics Case study: Neyshabour basin

Today, widening the gap between supply and demand serious attention to the principles of allocation and management of water supply and water demand is inevitable is necessary.In this regard Vensim model based on the theory of dynamic systems for planning and management of water resources and uses in the catchment of Nishapur in the KhorasanRazavi province were used. Finally policy scenarios are based on the proposed model was implemented. Results analysis of running various scenarios over the next 25 years in Nishabur plain to study the aquifer water level changes due to pressur irrigation systems development was done, so that the development of the first scenario (normal rainfall conditions) showed an increase in annual acreage about 1.38, acreage constant 0.95 and reduce the acreage of about 0.77 m drop in water table of the aquifer will see annual drowdown in aquifer levels over the course of the simulation and reality (about 0.87 m), respectively, an increase of 58 percent, an 8 percent increase and 12% decrease at will. So if fixing reduced acreage of agricultural land and ground water storage can be increased somewhat, and the severe decline in aquifer water level to prevent, however, the use of pressurized irrigation systems coupled with increased acreage loss of aquifer water level will be intensified.