Rain, rain, don’t go away

If we can ensure our plots and streets are designed well, it can go a long way in preventing flooding, says Anupama Mohanram

The recent flooding in many neighbourhoods in the city is a clear indicator of lack of a focussed plan to channel or collect our rain water. This has caused a lot of inconvenience to us, leave alone the fact that we were not able to collect this pure water for future use.

Although long-term Government intervention is needed to change this situation, we can all make a conscious effort to look at our plots, streets and neighbourhoods as smaller hubs that we can try to make better.

Looking back in time, decentralised rain water harvesting systems planned and maintained by local communities were common. The step wells of Gujarat and Rajasthan bear testimony to such planning. Shallow wells were popular as it was easy to visually identify water levels, and they were an indicator of water availability for the community during various times of the year. This translated to the conscious use of water. Rain water systems were planned taking into account ground slope, soil structure, and the communities’ needs.

In today’s context, to start with, there are a few measures we can all take within our individual plots:

1. Ensure 100% of rain water from our rooftops is planned to be captured directly for domestic use. Rain water filters at base of down pipes will ensure adequate filtration. Roof slopes and water pipes should be checked and cleaned periodically.

2. Ensure all the rainwater that falls on the ground is either percolated into the ground or led into a natural pond (if space permits) or a well.

One way to facilitate percolation is to minimise the amount of hard surface or paving on the ground. It is also imperative that rain water pipes designed for percolation are planned taking into account the terrain as well as the type of soil present to ensure maximum percolation into the ground. In case of places with high water table, wells or ponds could be used after providing adequate slopes on ground.

A rainwater harvesting structure harnessing rooftop water. Photo: C.V. Subrahmanyam 

3. Construct channels covered with grates at entry points to the plot to ensure any water from outside due to level differences is arrested at the gate. This can then be connected to a pond or well within the plot.

Looking outside our plots, we should ensure the roads and streets abutting our homes are planned with adequate slope to storm drains along the sides. This water can be collected at neighbourhood level into localised wells or tanks.

Also it is imperative for new home buyers to check that adequate provisions have been made to collect and channelise rain water within their plot or community rather than focussing only on the total built up area.

If we can each ensure our plots, streets and neighbourhoods are designed well, it can go a long way in preventing flooding, appreciating the rain and also effectively use our rain water.

The author is the founder of Green Evolution, a sustainable architecture firm.

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