Integrated resistivity and water chemistry for evaluation of groundwater quality of the Gulf of Aqaba coastal area in Saudi Arabia

• Published in: Geosciences journal (Seoul, Korea) Vol. 20; no. 3; pp. 403 - 413
• Main Authors: Batayneh, Awni T., Al-Taani, Ahmed Abdulkareem
• Format: Journal Article
• Language: English
• Published: Seoul The Geological Society of Korea 01.06.2016; Springer Nature B.V; 한국지질과학협의회
• Subjects: Aquifers; Coastal aquifers; Coastal areas; Coastal zone; Crop yield; Earth and Environmental Science; Earth Sciences; Electrical resistivity; Gravel; Groundwater; Gulfs; Irrigation water; Rocks; Saline water; Salinity; Seawater; Water chemistry; Water depth; Water quality; Water wells; Wells; 지질학; Saudi Arabia; salinity; electrical conductivity; Wenner-Schlumberger electrical array; Gulf of Aqaba coast
• DOI: 10.1007/s12303-015-0053-y
• ISSN: 1226-4806

The most productive lands in the coastal area of Saudi Gulf of Aqaba lie in Wadi Humeidah, where irrigation relies predominantly on groundwater. Crop yields have been lately reduced due to increased salinity of groundwater and have led to abandonment of some wells adjacent to the Gulf area. Geophysical and geochemical investigations were combined to assess seawater-contaminated zones in the shallow coastal groundwater aquifer and to identify subsurface geologic formation. The prevalence of Ca 2+ , Na + , Cl – and SO 4 2– suggests that weathering of surrounding rocks is potentially the major source of ions. Characterization of aquifer conditions up to a depth of 60 m showed that the groundwater aquifer is composed of three zones with vertically different resistivity values. The surface layer with resistivity of 30–1000 ohm-m, represents the alluvial sand and gravel. The second layer with lower resistivity values ranging from 0.6 to 70 ohm-m, indicates saline-to-brackish-to-slightly fresh water saturated rocks. The third layer extending up to a depth of 60 m is dominated by resistivity values of several hundred to several thousand ohm-meters, reflecting the basement rocks. While the groundwater is generally brackish, the salinity content varied spatially with TDS values that decreased in the northeast direction. The variations in TDS are related to multiple sources and primarily dependent on dissolution of saltbearing sediments, exploitation rate, over-irrigation with salty water, aquifer-bearing strata and the location of wells. Groundwater aquifers in the vicinity of the coastline were found to have been impacted by saline water. The central east area has a type of groundwater that is relatively less brackish.