Modeling of Groundwater Recharge by Rainwater Harvesting-Wadi Bayer (Case Study)

Wadi Bayer is one of Jordan's desertic areas with very low precipitation and limited water resources. It is a typical example of the Jordanian water scarcity chronic condition. Groundwater recharging strategy is one of the long-term solutions of such water scarcity problem due to harsh climatic conditions and high evaporation rate. The groundwater resources in the area are utilized by the Bedoins for their domestic and cattles' uses. The groundwater is abstracted through three shallow wells drilled in the course of Wadi Bayer. The limited amount of the groundwater in the area is attributed to the limited natural recharge through the wadi bed during the occurrence of floods. In this study, a location of recharging dike was proposed at a distance of 150-200 m to the south-west of the existing wells, its reservoir area was estimated by 0.0285% of the catchment area of Wadi Bayer, which reflects the rare runoff occurrence. A home-made spread sheet model and an HEC-HMS model were used in order to estimate the surface runoff. The alluvium deposits and Rijam formation are the only rock unit groupings in the study area. The permeability of the topmost 2 meters, which form the floor of the reservoir, is 11.82*10-2 cm/sec. The top soil column was tested for permeability in the lab through test pit excavation. Seven boreholes were drilled in the site with different depths ranging from 5 to15m, the permeability test was conducted for different depths, ranging between 7.331* 10-6 and 1.805*10-3. A groundwater model was run using Processing Mode Flow software to indicate the natural recharge in the area due to the filling of the reservoir from flood water, for 30 day- and 15 day- retention periods. It was found that the groundwater table will rise in the range of 0.33 to 1.5 m and 0.11 to 0.90 m for both retention periods, respectively.