Estimation of Natural and Artificial Recharge of Shahreza Plain Groundwater in Isfahan Using CRD and Hantush Models

Cumulative Rainfall Departure model (CRD) is widely used for estimation of ground natural recharge. This model is based on the groundwater balance and it requires random parameters. Moreover, an increase in the static level under artificial recharge facility is simulated using diffusion equations. Since Shahreza Plain is located in an arid and semi-arid area and given that rainfall is the major recharge source in such regions, in this study CRD model is applied in order to estimate natural recharge of Shahreza Plain groundwater. The amount of groundwater basin fed by rainfall was estimated about 177.2 million cubic meters using the CRD model. Also, by investigating and comparing available artificial recharge plans in Shahreza Plain it was known that in Kohrouyeh Project due to high soil permeability the increase in water table depth was higher than other projects and it achieves the maximum level of the water table within less time. By investigating the course of groundwater quality change in upstream and downstream boreholes of artificial recharge plans and given dewatering periods, we found that artificial recharge plans are generally effective in improving groundwater quality in the direction of groundwater movement but these changes are not significant. Hence, it is demonstrated that groundwater change mostly depends on the groundwater drop.