100 more rainwater harvesting sites to be established

Islamabad:The civic agency will constitute a team of experts to identify 100 more sites for launch of rainwater harvesting projects to be funded by the Federal Flood Commission.

It has already announced that out of 100 rain harvesting projects launched in the recent past, 90 projects have been completed. Now addition of 100 more projects will help save rainwater and utilize it for various purposes in the capital city.

Initial details revealed that eight factors would be considered while identifying sites including surface slope, drainage network, settlement, road and land cover, soil, geology, and runoff volume.

According to the experts, the suitable place for rain harvesting in residential units can be a paved area like a terrace or courtyard of a building, or an unpaved area like a lawn or open ground. A roof made of reinforced cement concrete (RCC), galvanised iron or corrugated sheets can also be used for water harvesting. The areas selected for earlier rainwater harvesting projects in Islamabad appeared suitable and are now providing desired results. The process is still under way because there are also some aspects that are yet to be addressed.

There are three main types of rainwater harvesting system: direct pumped, indirect pumped, and indirect gravity. In certain situations it may be possible to have a purely gravity system; though such occasions are rare.

An official has said "Islamabad has vast tracks of land including ravines that can be turned into water reservoirs for each sector for garden use. The soil for rain harvesting should be fertile and instead of saline or sodic. Sandy soil usually makes water harvesting infeasible as it renders high infiltration, and thus runoff does not occur. Ultimately, even with a large quantity of rainwater pouring in, the water cannot be conserved in the sandy soil."