Correct Option
The correct option isIt reduces the seepage of rainwater into the soil.
Explanation
Groundwater recharge is primarily driven by the process of infiltration, where rainwater seeps through porous soil layers to replenish underground aquifers. The rate of recharge depends heavily on the permeability of the surface material.
Statement Analysis:
- Concrete chemically reacts with rainwater. is Incorrect: Concrete is a chemically stable construction material. While it may undergo minor weathering over long periods, it does not chemically react with rainwater in a way that consumes the water or prevents it from existing as liquid water.
- It reduces the seepage of rainwater into the soil. is Correct: Concrete and asphalt are impervious (impermeable) surfaces. They physically seal the soil surface, preventing water from percolating downward. Instead of infiltrating, rainwater flows over the surface as runoff, which is directed into drains and sewers rather than recharging the groundwater table.
- It significantly increases the rate of evaporation. is Incorrect: While concrete surfaces can absorb heat and potentially increase local evaporation rates (Urban Heat Island effect), the primary hydrological impact causing low recharge is the physical barrier to infiltration, not the loss of water volume through evaporation.
- It contaminates the water with saline compounds. is Incorrect: While urban runoff from concrete surfaces often carries pollutants (oil, grease, heavy metals), this explains the quality degradation of water bodies, not the reduction in the quantity of groundwater recharge.
Key Takeaway:
Concrete acts as an impervious surface that blocks infiltration, converting potential groundwater recharge into surface runoff.