Evaluation of riverbank filtration to improve groundwater quality (Euphrates River, Karbala, Iraq)

Abstract

Groundwater is considered an important source of water supply in Iraq, but the poor quality of water makes it unsuitable for drinking purposes. To enhance the groundwater quality, River Bank Filtration (RBF) method was investigated. It is a natural process in which wells along a riverbank are pumped, causing some of the river water to flow toward these wells. With this technique, water coming from the river is filtrated by soil deposits and then mixed with groundwater, improving its quality. The purpose of this study is to evaluate the implementation of the RBF technique to improve the poor quality of groundwater and get potable water. A study area was selected in Al Hindiyah District within Kerbala City, Iraq. Four wells (W1, W2, W3, and W4) with different distances from the Euphrates River bank (450 m, 720 m, 800 m, and 1950 m), respectively, were selected to examine the groundwater quality. The results were then compared to those for the Euphrates River. In addition, two boreholes (B.H.1 and B.H.2) of about 15 m depth were drilled near the riverbank to assess the soil properties of the studied area. The results showed that the groundwater quality at a depth more than 12 m enhanced as the well’s distance from the river bank decreased and got closer to the river. It was found that the water quality at pumping wells (W1, W2, and W3) is slightly polluted, which makes this area more suitable for groundwater abstraction to provide the best water quality. The poorest water quality was for W4 at 1950 m from the riverbank, which indicates that at this distance the river bank filtration process is eliminated.