Effect of recharge from a check dam and river bank filtration on geochemical and microbial composition of groundwater
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ORIGINAL PAPER
Effect of recharge from a check dam and river bank filtration on geochemical and microbial composition of groundwater S. Parimalarenganayaki & K. Brindha & K. Sankaran & L. Elango
Received: 12 August 2014 / Accepted: 23 January 2015 # Saudi Society for Geosciences 2015
Abstract Check dams are often constructed across the rivers to store excess runoff and to improve groundwater recharge. Quality of groundwater around the check dam depends on the chemical and biological characteristics of the water stored in the check dam. The aim of this study is to determine the benefits due to changes in chemical and microbial composition of groundwater during the process of recharge. This study was carried out in and around a check dam constructed across Arani River, Tamil Nadu, India, where people depend on groundwater reserves for domestic and irrigation requirements. Water samples were collected from the river and surrounding wells and were analysed for chemical and microbial contents. WQI based on the chemical composition indicates that the groundwater was good in this area, but microbes such as Escherichia spp., Salmonella spp., Shigella spp. and Clostridium spp. were present. However, the microbial quality of groundwater is far better than the water stored in the check dam. Hence, production wells can be planned at a distance of about 400 m in the east so that the bank filtrate will take at least 60 days to reach the well. This will considerably reduce the microbial load and also the cost of post-treatment. Thus, river bank filtration may be adopted near the check dams so as to maximise well yield and to achieve natural filtration. This
S. Parimalarenganayaki : L. Elango (*) Department of Geology, Anna University, Chennai 600025, India e-mail: [email protected] L. Elango e-mail: [email protected] K. Brindha International Water Management Institute, South East Asia Office, Vientiane, Lao PDR K. Sankaran Centre for Biotechnology, Anna University, Chennai 600025, India
will also enable to use a portion of water that otherwise would be lost due to evaporation from the dam. Keywords Check dam . Drinking water quality . Geochemistry . Microbes . Managed aquifer recharge . River bank filtration . Water quality index
Introduction Groundwater is the largest freshwater resource, and 85 % of the rural population in India depends on it. The use of groundwater for domestic water supply is considered advantageous as infiltration of surface water results in removal of suspended materials and other substances. Agricultural activities also mostly depend on the use of groundwater especially in southern part of India. Extraction of groundwater for irrigation where it is slowly renewed is the main cause for depletion (Hertig and Gleeson 2012). Groundwater depletion and its impact are more obvious at the regional scale in agriculturally important parts of India (Hertig and Gleeson 2012). Check dams are often constructed across rivers as a method of managed aquifer recharge (MAR) to mitigate this problem. Different meth
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