بررسي تاثير استحصال و پخش سيلاب بر صنايع آب زيرزميني دشت گربايگان

Effect of floodwater spreading and consumption on groundwater resources in Gareh Bygone Plain.

The artificial recharge of groundwater (ARG) is a proven method of increasing the water level in unconfined aquifers. Although the ARG activities at the Kowsar Station have been proven successful due to an 8 fold increase in the area of irrigated farm fields, quantitative studies are lacking. We have been monitoring floodwater discharge and diversion to our ARG system and the piezometric level since 1992. These data were used to establish a relationship between the ARG events and the water table variations at the study site. Firstly, the water tables (WTL) at the time of recharge, and for 3 months after it, were grouped and the equipotential lines for the aquifer were constructed. Then the same data were grouped according to the months corresponding with the minimum and maximum pumping. It was observed that all piezometer, showed a rise in WTL for 3 months during the Oct. - Feb. period if there was an ARG event. The trend was reversed when there was heavy pumping during the irrigation season; thus the aquifer was sinking. The general trend in the area indicates an overdraft from the aquifer. It is interesting to note that the WTL in piezometer No. 2, which is located in the center of the ARG systems, shows a gradual rise, in spite of the opposite observation in other 3 piezometers. The lowest WTL is observed in piezometer No. 4, which is located at the center of irrigated fields.