Rapid urbanisation and developmental pressure are plagued with uncertainties in the future. This will impair any urban water management strategies that are insensitive to these factors. Hence, there is a need to develop processes that are robust, adaptable and sustainable to the future pressures. This calls for a paradigm shift in managing urban and peri urban water bodies. One of the solutions to the urban water crisis is through rainwater harvesting - capturing the runoff.

What is RAIN WATER HARVESTING ?

Rain water harvesting is collection and storage of rain water that runs off from roof tops, parks, roads, open grounds, etc. This runoff can be either stored or recharged into the ground water. Under the existing project it is proposed to channelize the rain water from roof tops and other areas into the lake. A rainwater harvesting system to revive the urban lakes consists of the following components:

• Catchment from where water is captured and stored or recharged
• Conveyance system that carries the water harvested from the catchment to the storage/recharge zone
• Storage tanks and/or various recharge structures



Rainwater harvesting can be harvested from the following surfaces




Rooftops: If buildings with impervious roofs are already in place, the catchment area is effectively available free of charge and they provide a supply at the point of consumption.




Paved and unpaved areas i.e., landscapes, open fields, parks, stormwater drains, roads and pavements and other open areas can be effectively used to harvest the runoff. The main advantage in using ground as collecting surface is that water can be collected from a larger area. This is particularly advantageous in areas of low rainfall and is proposed to recharge the lakes tanks and ponds to store rainwater. The harvested rainwater can not only be used to meet water requirements of the city, it also recharges groundwater aquifers



Stormwater drains: Most of the residential colonies have proper network of stormwater drains. If maintained neatly, these offer a simple and cost effective means for harvesting rainwater.


Rainwater Harvesting in Hyderabad (Andhra Pradesh)


• Rainwater harvesting has been made mandatory in all new buildings with an area of 300 sq m or more. Tentative for enforcing this deadline was June 2001.