The correct option is (c).
Explanation
Check-dams are small, low-level barriers built across the direction of water flow on shallow rivers, streams, or drainage lines. They are a fundamental component of watershed management and rainwater harvesting systems.
- Statement 1 is Incorrect:
The primary objective of a check-dam is to impound surface runoff to facilitate infiltration. This process significantly increases groundwater levels through recharge, rather than decreasing them. - Statement 2 is Correct:
Check-dams obstruct the immediate surface runoff of rainwater. By holding water in the catchment area, they prevent it from flowing away wastefully, allowing it to percolate into the subsoil. - Statement 3 is Correct:
By creating a barrier, check-dams reduce the velocity of water flow. Lower water velocity reduces the kinetic energy available to detach and transport soil particles, thereby effectively reducing soil erosion.
Key Takeaway:
Check-dams are vital for groundwater recharge and soil conservation, serving to retain surface runoff and reduce the velocity of water flow.