Environmental Challenges (Aug 2021)
Application of modified managed aquifer recharge model for groundwater management in drought-prone water-stressed Barind Tract, Bangladesh
Abstract
The core challenge of Barind Tract (BT), located in the northwest region of Bangladesh, is to make water available for agricultural, drinking, domestic, and other uses and ultimately for the survival of flora and fauna. Over extraction of groundwater for irrigation, less rainfall, fewer sources of surface water, high temperature, and thick top clay that limits the natural recharge are the major causes of continuous depletion of groundwater level (GWL) in the BT, which demands managed aquifer recharge (MAR) technique as the modified form matching with the lithology as well as the aquifer condition of the area. So, the study aimed to design, construct a recharge well (RW) and a water filtration unit as a specific MAR method to evaluate their performance for groundwater recharging through rooftop rainwater harvesting in the Barind Multipurpose Development Authority (BMDA) Mohanpur office campus, Rajshahi under the BT region. In this view, necessary data and information like rainfall, GWL, lithology, and other information related to the study were collected from the BMDA Mohanpur office and field investigation. Lithological samples of the Mohanpur office campus were collected through drilling arrangement, and grain sizes of the aquifer samples were analyzed in the laboratory, then designed the RW and installed at the BMDA Mohanpur office campus accordingly. A water filtration unit was designed considering the average maximum daily rainfall. Rooftop rain waters were collected from the office building and a training shed near the uPVC pipeline, filtered through the sand-gravel filtration media of the filtration unit, and finally recharged to the groundwater through RW. GWL fluctuation of the observation well (OW) installed near the RW was monitored using Auto Water Level Recorder (AWLR). Performances were evaluated based on groundwater recharge, GWL fluctuation with the rainfall, and quality of water. The study found that groundwater recharging occurred significantly, groundwater level rose when rainwater was infiltrated into the groundwater, and water quality parameters remained within the acceptable limit for drinking use according to standards like Bangladesh Drinking Water Standard (2005) and WHO (2008).
