Assessment of shallow aquifer salinity in the Aqaba Coastal plain using ERT method: a case study of Maqnah region, northwestern Saudi Arabia
Journal Article
Batayneh, Bahkaly M., & Awni T. . 2015
Magazine \ Newspaper:
Environmental Earth Sciences
Volume Number:
74
Pages:
2105-2114
Publication Abstract:
An electrical resistivity tomography survey has
been conducted along the eastern coast of the Gulf of
Aqaba in order to assess the salinity of the coastal shallow
aquifer. The study area is extended from Ra’s Shikh Humayd
to the town of Maqnah, northwest of Saudi Arabia.
Eight electrical profiles were conducted using the Wenner–
Schlumberger configuration. The total length of each profile
was 360 m providing an expected maximum depth of
penetration of about 50 m. All electrical profiles were
conducted perpendicular to the coast and directed in the
west–east direction. The inversion of the electrical data
provided a clear two-dimensional image of the subsurface
in the area that reflected the variations in the resistivity of
the shallow aquifer system. The subsurface is composed of
three layers: the upper layer corresponds to the dry alluvial
and gravel deposits that have resistivity values in the range
between 40 and 1400 X m. The second layer is the
saturated zone of the alluvial sediments which represents
the coastal aquifer in the study area. The resistivity value of
the saturated zone is in the range of 0.15 to 25 X m. The
lower layer in the subsurface stratification is the resistive
bedrock which has resistivity values of more than
100 X m. It is composed of Pleistocene–Miocene sediments.
The extension of saline water body has been mapped
along all electrical profiles. The interpretation of the
resistivity models shows that the salinity of the groundwater
in the area is strongly related to three main factors:
(1) the closeness to the coast; (2) closeness to wadis and
low areas which allow saline surface water to infiltrate into
the shallow aquifer and; (3) the abundance of gypsum
outcrop in the vicinity. This last factor emphasizes the
important effect of the local geological setting on the
salinity of groundwater; the abundant supply of leached
gypsum contributes to the salinity of the shallow aquifer.