Sunday, October 19, 2008

Eying rainwater harvesting as water crisis deepens

A girl collecting rainwater from an underground reservoir in Mirpur Photo: STAR
Dhaka - October 20 2008: Harvesting rainwater on the rooftop can be a possible alternative solution to acute water crisis in Dhaka city, experts say.

Many agencies, including the Dhaka Water and Sewerage Authority (Wasa) are studying the feasibility of rainwater harvesting as alternative source of water and a way to recharge the depleted groundwater table.

Mizanur Rahman, senior hydrogeologist, Institute of Water Modelling (IWM), currently conducting a study said, “Rainwater harvesting has immense possibility in Dhaka city. Bangladesh is a country of heavy monsoon. The water that goes down the drain and causes waterlogging every year can serve a better purpose.”

The capital city averages nearly 1,700 to 2,200 mm rainfall per year while the nationwide average is around 2,200 to 2800. Monsoon usually lasts from May to October and there is occasional rainfall also in November.

Dhaka city is situated on around 370 sq km of land with a roof area of 75 sq km as there are around 6,75,000 concrete houses in the city. With the current amount of rainfall IWM estimates that around 149160 million litres of water can be harvested during the monsoon. More >>>