Comparing groundwater recharge in sprinkler and furrow irrigated farms using unsaturated zoon modeling

For sustainable use and vulnerability assessment of aquifers, the groundwater recharge estimation is necessary. In Iran where located in a semi-arid region, the groundwater recharge is closely dependent on the return flow from irrigation. Therefore, determining the proportion of the return flow in recharge from different irrigation methods is essential for better management of groundwater resources. In this study in Neyshabour watershed, the recharge amount of two different irrigation methods (furrow and sprinkle irrigation) were estimated using soil moisture measurement in 2 wells of a wheat farm with 6 meters depth. In each well, the REC sensors were installed with 0.5 meter intervals and two sensors were also installed in 0.15 and 0.3 m depths. Using these sensors, the soil moisture was daily measured during 173 days. Then these values were used to simulate the unsaturated flow in these points using the 1D HYDRUS package. The model in each point was calibrated and implemented to estimate the drainage amount underneath the 6 meter depth soil layers. The drainage amount from 6 meters soil layer during 173 days in the furrow irrigation was 80 mm and in the sprinkle irrigation was negligible.