UlanBatori wrote:My sympathies to Chennai residents. Wonder if there is any way to route floodwater into places where it will replenish ground water. For much of the year Chennai and much of TN suffers from water shortage. I hear that California has been experimenting with flooding grape and other orchards and letting the water stand until it seeps in, and the initial results per Scientific America are that the grapes have flourished quite well in pilot tests elsewhere. Indian agriculture naturally depends on rain, but perhaps more should be done now, with so much of the surface taken up with construction. I know, I know... bad thing to be discussing while people are drowning, but that is when the rain water is available..
OTOH, what does this do to the famously fragrant canals of Chennai I wonder - isn't this an opportunity to demand a good cleanup, following the natural flushing? Floodwater is no fun, I know - it leaves a thick layer of gross mud even where it is not 50% sewage. I had the joy of trying to clean out the crawl space below my house in the past few weeks following a VERY MINOR flooding from rain runoff - and I am not even 10% of the way into it, already suffering from dust ingestion despite masks etc. Seems so EZ until one tries it on one's hands and knees in a 3-foot high space using a flashlight ...
First iteration of cleanup leaves the concrete floor still with a thick layer of mud...
These "200-year deluges" are becoming more frequent - or more recognized and reported - around the world. So planners and urban managers have to take these into account, and rainwater redirection I hope is part of that.
Ulan Batoriji - this topic is close to the heart of any non profit seeking non governmental non landmafia person in any Indian city
"Borewell recharging" or "rainwater harvesting" is a demand made of residents of plots exceeding certain area in Bengaluru, Kerala. The former consists of channeling all rainwater into a kiler pit that needs to be at least 30 feet deep - going through the subsoil rock into the "real" subsoil water region. Of course sham holes can be dug of lesser depth. Rain water harvesting is a way by which the city corporation can blame residents for flooding. It is a useless exercise for small plots. Pipes get clogged by leaves and overflow with the first rains and stagnant water after the last rain breeds mosquitoes.
The real issue is the the city corporation, development and state govt officials of cities like bengaluru and chennai for decades have lined their pockets by encroaching on water bodies and water channels in the form of selling that land to developers.
For example Bengaluru had something like 200 lakes - which are saucer shaped depressions in the ground with little channels ("rivers that run only in the rainy season") that connected up the lakes - so that rainwater first fills the lakes and the channels allow overflow into a more distant lake. In the dry season the lakes maintain the grounddwater levels.
What they have done in Bengaluru (and Chennai, I am told) is to sell the lake beds for building and "development" and once the lake bed is built over the channels are permanently dry and they can be built over as well. Everyone in the city knows this, but no one has taken the trouble to inform the rainclouds and the water of this little inconvenient fact. The rain continues to collect in the saucer shaped depressions - and floods the buildings there up to several feet. the overflow water - having nowhere else to flow, flows on the roads. Meanwhile the population, having suddenly been exposed to the joys of plastic wrapping on everything simply dump the plastic on local dumps. Those dumps get washed into drains and drains if any, get clogged. Thus we get the modern Indian city. Of course I hear that this same model is followed in cities across the world - but that does not concern me.
Bengaluru actually has thriving (and some upmarket) residential locations like "CT bed. CT bed sounds so cute for the techie who has moved in from outside Bengaluru and paid 2 crore for a flat. CT bed is actually "ChennammaneKere Tank Bed" 'Chennamma's lake bed". There are dozens of localities built on lakes in Bangalore and Chennai. The local government bodies who know no planning and who have made loads of money have simply allowed this construction to occur and those areas become lakes once again. There is no easy short term solution. Removal of the corrupt builder-government nexus is necessary, but it is easier said than done
