Terms like global warming and rainwater harvesting are comparatively new in our daily parlance. But global climate change has been going on from the day our planet came in to being. Yes we were not there to experience the intense vagaries of climate. Similarly, Rainwater harvesting has been going on since centuries, particularly in the water deficit areas of the country with no particular name for the process. The environmental jargon is such that it makes simple processes sound complicated. Harvesting sounds as if some crop is being harvested. The environmentalists perhaps felt more comfortable in calling it harvesting than collecting.
Those who come from water deficit areas like the habitats on the Himalayan ridges and slopes, high altitudes, deserts or the rocky parts of peninsular India will recollect how their grannies use to place large vessels to collect rain water after the first showers. The first showers were avoided as they contained dust particles. In Uttaranchal the sloping roofs made of slabs of slate had a tin channel running all around the edge. The channel had one or two outlets from where the rain water would gush out. Instead of a down pipe a portion of the channel projected for two three feet straight overlooking the courtyard. Rainwater as it poured out from these outlets was collected in huge brass vessels covered with muslin cloth. It worked as a strainer plus lid for the stored water.
In a water deficit area where each drop of water matters the water so collected was used for days to wash clothes. In addition while it rained soaped clothes like bed sheets etc. were put near the vessel to be washed and cleaned by the spill off.
This is what rainwater harvesting is about. Now with advent of sciences like environmental engineering the scientists have to make their living and people will not buy the idea unless high sounding terms are prefixed. Perhaps it is a kind of brand management!
Rainwater collection by a household can be considered as rainwater harvesting on a micro-scale, similar but on a larger scale which could be termed as water harvesting on a macro-scale has been practiced elsewhere in the Himalayas. In Spiti, the famous rainless and cloudless terrain, supposed to be a desert but surprisingly agriculturally rich district of Himachal Pradesh, an ingenious system is in use since centuries. Kul or diversion channels are made from nearby ice bodies, locally termed glaciers, though strictly speaking none of them are a glacier.
These stone-lined, 'kutchha' channels carry water from the melting ice straight to large pond in the village. Further flow of water from the pond to fields is regulated as per the need and entitlement or water rights. Earlier the system was managed by the people. Of late the state government has taken over. While in the hands of the society the maintenance of the Kuls or cleaning at the head of the Kul at the glacier was done by the people. Water rights were decided as per the labor done by a family. Now since the government's take over in the name of equality no one gets water, because kuls are never repaired for want of funds, availability of labor or similar reasons.
Similar methods are used in the northeast Himalayas where springs are tapped and water is carried to fields through bamboo channels. This is common in Meghalaya especially in Khasi and Jaintia hills. Bamboos of various diameters are used as conduits of water from the spring straight to the crops. The arrangement is such that only a trickle of water reaches the crops of black pepper or betel leaf. In other words this is a 200 year old 'drip irrigation' system.
Water starved Thar Desert has been practicing rainwater harvesting since 4500 BC. Efforts were made to ensure that not even a drop of water is wasted. It was also ensured that rainwater must not be allowed to be lost into oblivion of the sand. Along the pre-defined routes the Caravan travelers built 'Kuis' or 'Beris'- structures that collect rainwater and do not permit evaporation. As the construction techniques improved better designed 'Kundis' or 'Kunds' were made, which are still used even today to store water. These wells are made in the topographic lows and rain water reaches them through drains which are lined with local clays and kept meticulously clean. In addition there are 'Chandela' and 'Bundela' tanks with stairs to reach even when water level went low. These tanks are always surrounded by beautiful gardens.
A common factor for all above methods is that our ancestors knew the value of water and developed ingenious ways to conserve it.
With concrete jungles developing fast in place of forests, population bursting at the seams, and the shrewd private operators trying to bottle and sell whatever water can be grabbed scarcity of water is becoming a serious problem. The problem is compounded by fact that most urban areas water used for washing the cars and irrigating the lawns is the same which is used for drinking as well. Because availability of water is cheap the concept of saving water does not exist in the mindset of the government or the society. Millions of litres of water is leaked out daily through the water supply pipes. Households do not hesitate to use water guzzling showers and other devices. All because water is almost free.
Subsurface water is like a Bank Account. If money is continuously withdrawn without any deposits the account is bound to be in red. Same way large chunks of aquifers are becoming bank corrupt because of less recharge and more withdrawal.
How best a family can help in recharging the water account and what the society and government can contribute is all what we would be reading through this column in the forthcoming weeks.