Chapter 28, Problem 6RQ

To determine

The effect on land surface when the pumping of groundwater is greater than the recharge.

Answer to Problem 6RQ

If on a piece of land, the pumping of groundwater is greater than the recharge then the land surface will get lowered.

Explanation of Solution

The land surface where the pumping of groundwater is greater than the recharge then the land surface will go down to a lower level. When the pumping rate of groundwater is higher than the recharge rate, then the water table will drop which will cause lowering of the land surface. This mostly happens when the ground and soil beneath comprises of thick layers of loosely placed soil instead of tightly packed soil. These layers consists of various layers of clay which is compressible. Now as the water is pumped on such a land, the water of the clay expels out and the clay is compacted which causes the lowering of land surface.

Conclusion:

Therefore, if on a land the pumping of groundwater is greater than the recharge then the land surface will get lowered.