What is a good monsoon? 60%,100%,115%? Ahmedabad seems bypassed by ‘Bountiful 2016 monsoon’ headlined in the papers. For all the shouting, we are way behind other states in being water smart.
Rainwater Harvesting is not yet compulsory in all housing societies, despite its success elsewhere. Institutions and new developments are covered by Ahmedabad Municipal Corporation/ Ahmedabad Urban Development Authority bylaws. But, how much actually happens in new concrete jungles with deep parking basements and paved courtyards? And has awareness of minimizing water usage been created at all levels?
80% water consumption is relatively clean water that can be recycled. This quantum increases with lifestyle. Percolated underground it can recharge groundwater to create a self-balancing system that would also reduce AMC gutter overload – possible answer to rising population densities. The remaining 20% water, from toilets, has to be professionally managed by municipalities.
Experts opine that only recharge of both rainwater and domestic water can perhaps meet rising demands. In an earlier era, Ahmedabad experimented with Percolation Wells. 20/30 ft deep, with filter for pollutants, these slowly pour rainwater (domestic too in societies) back into the groundwater table. Although they cannot replace storm water drains, they do help – except when flooding thunderstorms occur.
Mayurbhai Shah’s percolation wells in his private housing societies served as model for those set in empty public spaces, traffic islands, open basements of earlier shopping complexes etc. Over time, siltation happened. Failure to cope spelt death of those wells!
Percolation wells are also possible near bore wells which are biggest culprits in lowering water tables; perhaps work better in rural areas where farmers are more amenable to the responsibility of desilting.
Another defunct experiment was the combining of the cattle trap at society gates with a percolation trench that would trap runoffs from parking spaces and pavements etc to avoid street water logging. Again, lethargy at desilting, private and public, spelt a death knell.
Trenches can route flood water away from buildings and into rivers and streams with minimal erosion. Bio-retention basins in commercial developments, traffic islands, gardens have become a buzzword in containing runoffs, soil erosion and pollutants in rainwater. Aquatic plants and mulch layers trap many pollutants, a clayey layer filters out metals and a deep layer of sand then allow cleaner water to recharge groundwater strata without contamination. Plants stem soil erosion.
In private yards, little rain gardens, ponds with conditioned soil and flood tolerant vegetation can trap runoffs, filtering solids + pollutants before recharge.
The Ahmedabad Municipal Corporation standing committee ordered rainwater harvesting in municipal schools. Some funds were allotted. Action taken?
The school board actually boasted of pipes to reuse rainwater during the monsoon to water plants in the compound? Is that even needed?
Meanwhile, 10 areas identified suitable for percolation wells. And five dysfunctional wells made functional in a would-be Smart City with natural resource depletion, both green cover and ground water.
How Ancient India Coped
Is it not ironic that with an estimated 400 million hectare meters (MHM) of rain, India’s annual requirement at the turn of the century was a quarter of that at 100 MHM?
With a billion plus to cater for today, corresponding demands for agriculture etc. may have gone up, but still nowhere near what is available and allowed to flow off for want of conservation.
The saddest part:
This is a monsoon dependent country with a Hoary Experience in saving up to 66% of precipitation, on an “as is where is” basis; the antithesis of the 20 odd % in magnificently humongous dams inherited from an Occidental culture, showing off its power over Nature.
That famed 66% happened in pre-British India, testified by Major R H Sankey in 1866 when taking charge in Mysore (remember the administration of Tipu Sultan?). He wrote:
“…… to such an extent has the principle of storage been followed that it would now require some ingenuity to discover a site …suitable for a new tank….”.
That then was the dictum of ancient India water conservation:
Store water where it rained.
Since Time Immemorial, hundreds of thousands of reservoirs known by different names testifying their universality dotted the countryside, from the hilltop sources down to the sea, overflow of one flowing down to the next, in natural catchment areas.
The water bodies allowed percolation, supplemented soil moisture, reduced soil / land erosion and maintained atmospheric humidity.
No long canals to make for seepage, siltation, salinity and evaporation that plague our modern dam canals.
Anyone or everyone could sponsor a tank: king, commoner, even the philanthropic village prostitute. The Arthashastra is a mine of information. Water bodies varied in size and depth to irrigate command areas, from ten lowly acres to tens of thousands.
The creation of such massive numbers of water conservation bodies threw up an amazing range of specialized Castes, each expert in different aspects, from stone and earthworks, to reservoir and well construction, weirs, canals and channels, even distribution - usually entrusted to traditionally landless Nirkuttis who had no stake in the water. To this day, descendants of those castes remain the backbone of irrigation and R&B labor gangs.
Maintenance was communal before the monsoon onset. Tanks were drained and cleared; silt removed, distributed as fertilizer within the community. Every household participated, personally or nominees … more like a village mela with all those accouterments too.
Today surveys bemoan the poor penetration of piped water in Kerala – totally overlooking their rich heritage of wells for drinking and irrigation purposes;
Bengal’s legendary prosperity was drowned in malaria and poverty, after the destruction of the 2000+ year old overflow irrigation canals (similar to those of the Nile, no one knows who learnt from whom.) Those broad shallow canals irrigated and fertilized the soil and bred millions of fish feeding off mosquitoes’ larvae: a unique combo of health and plentitude that bred generations of Bengali artists and scientists.
It was these developments from all over the country that powered the India fables.
Desi Jugaad, (Innovation) anyone?