Integrated approach of field and geophysical methods for the investigations of subsurface geology and potential sites for the artificial groundwater recharge in the NW part of Jordan
Mohammad Tarawneh, MR Janardhana
In arid and semi-arid regions paucity of surface water resources exerts a great demand for groundwater. Successful application of artificial recharge method to augment the demand for groundwater warrants both direct and indirect approaches in the identification of potential sites for artificial groundwater recharge. The present study involving field studies, core log data, remote sensing technique and electrical resistivity soundings was carried out at the northwestern part of Jordan to identify suitable storage sites for the artificial recharge of the water bearing formations. A suitable storage site offers a great scope to meet the demand of water during the lean periods. Forty-three Vertical Electrical Soundings (VES) using the Schlumberger configuration of electrode array to map the subsurface geology have been conducted with maximum current electrode separations of 600 m. Distribution of the resistivity values at different depths are represented by iso-resistivity and electrical profile maps for different electrode spacing. Correlation of the obtained resistivity values with the geology of the area showed that five to six layers with varying hydrological properties exist in the study area. The study area was divided into three zones based on the feasibility for artificial recharge of groundwater; ‘Most Suitable’, ‘Fairly Suitable ' and ‘Less Suitable’. The southern and southeastern parts of the study area are identified as ‘Most Suitable’ area for the artificial recharge of groundwater as the area is characterized by a huge thickness of alluvium deposits. Water table in this part of the study area is found at greater depths thus signifying its capacity to receive high amounts of recharge water for storage. ‘Fairly Suitable’ area for groundwater artificial recharge is the northern part of the study area as it has medium to large thickness of alluvium deposits and water table at moderate depths. The central part of the study area is ‘Less Suitable’ for artificial recharge of the aquifer as water table is found at shallow depths although the thickness of the alluvium deposit is significant.