Subtopic: Overview of groundwater recharge estimation and artificial recharge techniques
Question Statement:
Which of the following techniques and structures are widely adopted for artificial groundwater recharge in hard-rock agricultural watersheds?
Options:
(A) Percolation tanks constructed across seasonal natural streams to impound surface runoff and induce vertical infiltration
(B) Recharge shafts excavated through low-permeability topsoil layers to guide silt-free surface water into underlying permeable strata
(C) Check dams and nala bunds built across low-order drainage channels to retard runoff velocity and promote percolation
(D) Subsurface drainage tile pipes placed beneath the impermeable layer to pump saline leachate directly into deep fresh aquifers
Answer Key:
A, B, C
Step-by-Step Solution & Explanation
• Percolation tanks, recharge shafts, and check dams/nala bunds are standard, effective artificial recharge structures recommended by the Central Ground Water Board (CGWB) for hard-rock areas (A, B, and C are correct).
• Pumping drainage leachate into deep aquifers causes severe contamination of freshwater reserves (D is incorrect).