Mumbai needs 1 . 4 × 10 12   L of water annually. Its effective surface area is 600   km 2 and it receives an average rainfall of 2 . 4   m annually. If 10 % of this rain water is conserved, it will meet approximately

Step-by-step solution

Surface area over which rain is A = 600   km 2 = 600 × 10 3 2   m 2 = 6 × 10 8   m 2 Average rainfall, h = 2 . 4   m Volume of water received by rain, V = A × h = 6 × 10 8 × 2 . 4   m 3 Water conserved = 10 % of volume received by rain = 6 × 10 8 × 10 100 × 2 . 4   m 3 = 1 . 44 × 10 8   m 3 = 1 . 4 × 10 8 × 10 3   L = 1 . 4 × 10 11   L Percentage of total water consumption received by rain is = 1 . 4 × 10 1