|Residential roofs account a maximum of 15% of a city's footprint. Private residential plots about 30%. While this a must tap in terms of rainwater harvesting, why neglect the remaining 70%?|
Currently, our civic agencies treat rainwater like the plague, encouraged more to draining it away as quickly as possible. What little benefit we get currently is perhaps a result of their (and our) sloppiness.... clogged drains, illegally created structures, etc, creating check dams allowing some of this rain to percolate into the soil. But why cant we address both these issues of recharge and drainage simultaneously? Consider creating holding ponds (opposite to closing lake, tanks and valleys), and percolating channels (instead of concrete lined drains and canals) for a start.
|Bangalore city's rainfall distribution. The current demand is close to the|
rainfall potential on private residential plots, but what about tomorrow?
The truth is that in most of our cities and towns, a large percentage of the water need is met by drawing it from the ground. When this is not countered by adequate replenishment of these reservoirs through appropriate harvesting it leads to depletion of the ground water table. What compounds this is that water is used by industry, institutions and commerce too.... a lot of this not met by the civic agency's supply!
|A city like Bangalore has the potential to host nearly twice its|
current population if only it harvests the annual rains well
We are back to what a city's administrative bodies can do. We need to look at a city as a very large community on a very large parcel of land. Where rain falls should become the responsibility of the group that is in charge of that area. So, like when rain falls on private residences they have to harvest, similarly, if it falls on roads or parks it should become the responsibility of the municipality, or, when it falls on a govt institution's land they should be. Get the remaining land holders like the defence establishments, religious institutions and industry to do their bit. They are a part of a city's dynamic aren't they? The city water supply authority (in Bangalore) has taken some steps, like the proposal for the rejuvenation of lakes to serve as alternative reservoirs, or the proposal to treat sewage and loop it back for consumption, to address the city's growing water need. However, we need a clear and comprehensive water plan, that can cover a wide spread harvesting / recharge plan, that lists out separate maintenance, appropriate treatment, public accounting and specific responsibilities of all groups concerned. We are all players in this community that we call a city, and we all need to do our bit to share the responsibility.