|
|
| Total area Population | 437 sq. km |
|
120 lakhs 20 lakhs |
| Daily water supply (Per capita) | 135 litres. |
Rapid and unplanned urbanization, a continuous influx of commuters, coupled with losses during distribution has resulted in the “water crisis” . This has also led to reduction in the water supply to 90 litres per capita per day (lcpd).
Demand and Supply
The gap between demand and supply is widening day by day. At present Mumbai needs 3400 million litres per day (MLD), but it receives only 2950 MLD from the BMC. The problem is expected to aggravate by the year 2021, when demand would exceed 5000 MLD.
Water harvesting Potential
The total amount of water that is received in the form of rainfall over an area is called as the rainwater endowment of that area. Out of this, the amount that can be effectively harvested is called “ the water harvesting potential.”
Water Harvesting Potential == Rainfall (mm) x Collection Efficiency.
Collection efficiency is influenced by runoff coefficient and first flush wastage. [Top]
Water Harvesting Potential of Mumbai
Area of Mumbai = 437 sq. Km.
Annual Avg. Rainfall = 2000 mm
Total rainwater falling over Mumbai
= 437 x 1000000 x 2000 litres
= 874000000000 litres
= 874000 million litres
= 2394.52 MLD
Present Water Supply = 2950 MLD
Even if we assume that 70 % of the area to be developed, 50 % of it to be roofed and we collect 70 % of the water falling over it, the quantity of rainwater that can be harvested works out to be 589.34 MLD. This is a sizeable quantity compared to the water supply of Mumbai. (It may also be reminded that our Middle Vaitarna project is for 455 MLD). [Top]
