Rising groundwater levels problem in urban areas: a case study from the central area of Madinah City, Saudi Arabia

Abstract

In this research, the hydrogeological conditions in the central area of Madinah city, Saudi Arabia, were investigated in an attempt to gain insight into the shallow groundwater table rise problem that has recently been observed in this important location. Four wells were drilled in the study area, and soil samples were collected during the drilling process for lithological characterization. Water level in each well was recorded, and water samples were collected from the wells and analyzed for all important water quality parameters including temperature, pH, turbidity, electrical conductivity, dissolved oxygen, total dissolved solids, biochemical oxygen demand, bacteriological parameters (total coliform, fecal coliform, E. coli), major anions and cations, heavy metals, BTEX compounds and organophosphorus pesticides. In addition, geophysical loggings were conducted on two of the wells and a pumping test was conducted on one of the wells. Results revealed that the hydrogeological features in the study area consist of a top impervious layer, followed by a productive confined aquifer that extends over basement complex bedrock. Water quality analyses showed that the groundwater in the study area is not contaminated by leakage from different sources, indicating that these sources are not major contributors to SWTR. Most likely, the partial blockage of groundwater flow by large infrastructure in the study area is responsible for the SWTR. Results obtained from this research provide useful information regarding the hydrogeology of an important area and can aid authorities in preparing well-founded scientific plans to deal with SWTR problem including the appropriate reuse of excess water.