(a) The water reservoir is a pond in figure (1) and underground water body in figure (2).
(b) Figure (2) has more advantage than figure (1), because the advantages of water stored in the ground are many such as :
(0 It does not evaporate.
(ii) It spreads insufficient availability of dissolved oxygen and nutrients resulted in the death of fish.
(iii) It provides moisture for vegetation over a wide area.
(iv) It is protected from contamination by animal and human wastes.
(v) It prevents breeding of insects.