The groundwater resource of our country is now under serious threat due to over-exploitation, pollution, industrialization and improper management. The recharge shaft is an efficient and economic method for recharging groundwater. In this study, the effect of variable thickness of coarse sand (CS), gravel (G) and
pebble (P) layers of the filtration unit of the recharge shaft on the recharge rate and the sediment concentration of effluent water was evaluated. An experiment was carried out with laboratory-scale models having varying depths of CS, G and P layers in five different thickness combinations, viz. 1 : 1.5 : 3, 1.5 : 1 : 3, 3 : 1 : 1.5, 3 : 1.5 : 1, 1 : 1 : 1 (CS : G : P). These models were operated with six different treatments having varying concentrations of turbid water, similar to the sedimentation level of the surface run-off ranging from 6 to 16 g/l. It was observed that higher thickness of CS resulted in reduction of the recharge rate, but improved the filtration
of the effluent. Overall, considering both the recharge rate and sediment concentration of the effluent, the filtration layer thickness ratio of 1.5 : 1 : 3 (CS : G : P) would be the optimal design of the filtration unit to facilitate higher recharge and perform better filtration of the turbid water.