Performance of MAR model for stormwater management in Barind Tract, Bangladesh

Abstract Bangladesh is a riverine country, but its north-western part, popularly known as Barind Tract, is mostly drought-prone and faces scarcity of water. Because of very limited surface water resource, groundwater is the main source of water for drinking and irrigation purposes. The increasing demand and withdrawal of groundwater result permanent depletion of groundwater level (GWL). Due to low infiltration capacity the monsoon rainwater cannot percolate through thick surface clay layer (Barind Clay of Pleistocene age). So an attempt is made in the present study for artificial recharge of aquifer by adopting Managed Aquifer Recharge (MAR) model through recharge well (RW) and recharge shaft (RS) installed in Khari (canal) bed for infiltrating flowing rainy season storm water. The study also compares performance and effectiveness of application of conventional MAR model with the modified engineering model as viable adaptive menu to restore the depleting GWL. The conventional MAR model has functioned well initially, but recharge rate (RR) has gradually reduced (1.5–2.5 L/min) from the initial stage (28.64–48.0 L/min) due to clogging of the recharge units with clay (Barind Clay). To improve the recharge capacity, modification of the engineering design in MAR model has been adopted and their performance have been assessed. In modified MAR model, it is possible to replace clogged sand layer any time even during storm water surge in the Khari. Performance was more effective with increased amount of recharge than that of conventional one in the long run. Moreover, the groundwater quality has improved due to dilution process, and found suitable for drinking purpose within acceptable and allowable limits of BDWS (2005) and WHO (2008). Finally, in-depth research activities and regular monitoring and maintenance are necessary for fruitful operation of MAR model to elevate the water scarcity for drinking and irrigation purposes in the area.