Effect of watershed dam on groundwater level (Lavar earth dam)

The managed recharge of groundwater is a stable and newfound technique which has already produced successful results and is expected to solve many of the problems of water resources, particularly in arid and semiarid areas. Artificial recharge of aquifers is considered as a strategy for the improvement of groundwater resources and their storage capacity to compensate for the damages inflicted on them. In Iran, funds are annually allocated to artificial recharge projects. Assessing the effects of these projects on aquifers is important, since positive results can expand the implementation of these projects. This investigation was carried out in the Lavar-e- Fin plains. The aim of this study was to evaluate the effects of a dam on groundwater. We estimated groundwater level before and after construction of an earthen dam. We used library data, data collected by the Ministry of Energy and information recorded during fieldwork. We used water level data from 6 piezometric wells drilled by Regional Water Company of Hormozgan Province and monthly precipitation data during the period from 1995 to 2015. All piezometric wells were located downstream of the dam. The effect of the earthen dam on groundwater level changes were analyzed over a 20-year period and for before and after construction of the dam. The general trend of groundwater level and water level changes in each piezometer well was descending, despite the positive influence of the earthen dam. The results showed that the dam lowered the rate of water level drop. The average precipitation in the 9 years prior to the construction of the dam was 182 mm, while the average rainfall in the next 11 years was 155 mm. In general, the results of this study showed that in spite of the recent droughts and increased uptake of groundwater, Laver dam has had a positive effect on the water level of the aquifer. Although the dam has not been able to compensate for all the losses due to overharvesting, it has reduced the severity of the decline to a large extent.