Investigation of the effect of changing irrigation methods from traditional to modern on compensating the deficit in Neyshabour plain aquifer using the SWAP model

Decline in groundwater table and annually deficit more than 200 MCM, are the most important challenges in the Neyshabour plain aquifer of Khorasan-e-Razavi province. This research was conducted to study the role of developing the modern irrigation systems on sustainable management of groundwater resources. The effects of existing irrigation practices were evaluated using the Soil-Water-Atmosphere-Plant (SWAP) model. After model calibration, scenario of pressurized irrigation systems development for balancing the recharge and discharge of groundwater was studied. The results showed that change from surface irrigation to pressurized irrigation could cause decrease in water irrigation consumption (0-60%), decrease of deep percolation (2-90%) and improve in water productivity (0-140%). Use of modern irrigation systems for 30% of the total cultivation area of six main crops in the Neyshabour plain can decrease the discharge of groundwater aquifer about 22% without reducing in crop production. This is equal to 43 MCM of groundwater savings in the Neyshabour plain scale. If the results extend to other crops, it is expected that the scenario of pressurized irrigation systems development -without an increase in the area of cultivation- can compensate for 30% of the aquifer deficit in the Neyshabur plain.