CBSE Class 10 Answered

There are several advantages:

i) Greater quantity can be stored as ground water.

ii) Ground water is relatively less vulnerable to pollution

iii) Ground water has distinct health advantage as an alternative for lower sanitary quality surface water 

iv) Ground water is usually of high bacteriological purity and is free of pathogenic organisms.

v) Ground water needs little treatment before use.

vi) There is no conveyance losses in ground water based supplies.

vii) Ground water does not evaporate easily

viii) Ground water reservoirs are environment friendly and economically viable proposition.

In addition the sub-storage reservoirs have advantages of being free from the adverse effects like inundation of large surface area, loss of cultivable land, displacement of local population, substantial evaporation lossesand sensitivity to earthquakes. No gigantic structures are needed to store water.  The structures required for recharging ground water reservoirs are of small dimensions and cost effective, such as check dams, percolation tanks, surface spreading basins, pits, etc.