Aquifer salinity and its impact on drinking water and agriculture in Kalia upazila of Narail district

Abstract

In Bangladesh, salinity in coastal aquifer is a common problem which is expected to be exacerbated by climate change and sea-level rise. At present, salinity intrusion due to reduction of freshwater flow from upstream, salinization of coastal groundwater and increase in soil salinity are major concern of Bangladesh. Salinity is a vital issue to the people of southwest region. Due to the presence of salinity in groundwater as well as surface water, the people of the southwest region are suffering from problems related to drinking water, irrigation, agriculture, fisheries and other uses. In this regard, the present research is carried out on Kalia upazila of Narail district which is located in the southwest region of Bangladesh, comprising an area of 317.64 sq km. The research is aimed at evaluating the spatial (i.e. horizontal) as well as vertical distribution of groundwater salinity in the study area and its impacts on drinking water and agriculture. For this purpose, this study used two widely used parameters for evaluating salinity - electrical conductivity (dS/m) and chloride concentration (mg/l) of groundwater at different unions of Kalia upazila from BADC water quality reports from 2004-2007 and interpretation of geophysical log from DPHE. Field visit has been carried out to investigate present condition of salinity and its influences on community. A questionnaire survey has been carried out in the study. The study shows that the eastern and western parts of Kalia upazila have higher salinity trend whereas the north central part is more or less salinity free. The Joynagar union has the highest electrical conductivity of 4.5 dS/m and Mauli union has the lowest electrical conductivity of 0.7 dS/m. For drinking purpose only the DTW water appears to be suitable from salinity. The study also shows that out of 14 unions, water from 7 unions has higher chloride concentration which is beyond acceptable limit for irrigation.