Evaluation of Depositional Environment and Aquifer Condition in Barind Area, Bangladesh Using Gamma Ray Well Log Data

Abstract The depositional environment and aquifer condition of the Barind area of Bangladesh were studied using gamma ray log data Attempts were made to evaluate the aquifer potentiality, either single or multi-layer considering thickness, depth of occurrence and viability of exploitation Study indicates that sedimentation occurred in floodplain to point or channel bar environment In the sandy layer in the western part of the study area less matured coarser sediments were transported from shorter distance The area is covered by 3 0-47 5 m thick semi-impervious clay-silt layer of Pleistocene to Recent age and is characterized mostly by single aquifer within the depth range of 9 0-51 5 m below ground level But in the eastern, southeastern, southern, northeastern and northern parts aquifer system of Plio-Pleistocene age is multiple layered (two-four) with thickness of 5 0-42 5 m at different depth levels In the northern and southern parts of the Central Barind Tract and the Atrai valley potential aquifers occur at different depths shallow (up to 30 0 m from GL) and intermediate (30 0-50 0 m from GL), and deep (> 50 0 m from GL) The southeastern part of the Tract is more potential for deeper aquifers than other parts Usually, the average discharge of a well in the area is 2 cusec (56 6 Ips) but as result of innovated and cost effective drilling and construction DTWs produce desired discharge of 3 cusecs (84 9 Ips) with reasonable specific drawdown, increased specific yield and better well performance (with 2 9 times more specific capacity) Central part of the area with T<500 m2/day refer to as suitable for development of water supply and pump use, but the rest the area with T=500->1000 m2/day indicate good development potentiality for irrigation and water supply