Simulation of Groundwater from Qaemshahr- Juibar Catchment under Performance of Alborz Irrigation and Drainage Network

Incorrect management in Watersheds causes disorder of natural balance in groundwater resource and problems from water drawdown and consequences caused by non- optimum use of these water resources. In this research, in order to investigate the effect of construction of Alborz irrigation canals network on water table of Qaemshahr-Juibar Watershed and determination of maximum permissible water withdrawal from groundwater by water users associations of the region, in the condition of the performance Alborz network, the MODFLOW model was used. Besides the seepage water conveyance canals, recharge and discharge from the aquifer by Talar and Siahrood rivers, wells, return flow, rainfall and evaporation were all considered in the model. The model was run for a period time octobr 2004 to September 2004 in unsteady flow condition and was calibration with comparing observed and simulation water level. For model validation observations data for octobr 2008 to September 2008 was used the amount of RMSD was 0.2. after examined the model, the aquifer was evaluated in three scenarios: 1) Aquifer condition before alborz irrigation and drainage network performance, 2) after performance and 3) withdrawal groundwater optimal conditions. The results showed, after Alborz design performance, Rise of water table it was 3 meter for one year. And the possibility of creasing withdrawal from ground water resources was 96 million cubic meter per year.