Rainwater harvesting can also improve the eco-system and health. It can reduce river and stream erosion by managing storm water run-off. The fear of chlorine and the need for purification is taken care of
As per the Indian Meteorological Department, the current monsoon season has seen normal rainfall and, in fact, excess rainfall in some parts of the country. However, the apathy towards conservation of excess rainwater is writ large across the country.
In the national capital alone, approximately 69 billion litres of rainwater hit over 140 sq km area of rooftops in the city, with an average of 490 mm rainfall annually. However, how much of this water is actually conserved is a matter of concern, as only 300 to 400 establishments including schools and residential colonies have properly implemented rainwater harvesting. The city is still not serious given the fact that there is no active monitoring to ensure the implementation of the rainwater harvesting facilities in new structures.
According to the projections of The Central Ground Water Board, ground water recharge can be doubled if establishments and households have rainwater-harvesting facilities and the same are properly implemented everywhere.
Add to this, the Government establishments instead of setting examples for the citizens are being questioned for allowing excess rainwater to go waste. The Delhi Metro Rail Corporation in July 2013 admitted before the National Green Tribunal that 42 out of its 105 elevated stations do not have rainwater harvesting facility resulting in eight crore litres of rain water being wasted every monsoon.
Given the massive depletion of groundwater table, this kind of waste is unaffordable. At the same time there are examples to the contrary. The city of Chennai which once reeled under water shortages is now self-sufficient due to the stringent application of rainwater harvesting guidelines for new as well as old structures. Yet, many smaller cities are not faring better due to the absence of requisite infrastructure as well as the will to prevent excess rainwater run off.
For example, Aurangabad received 300 mm rainfall since June 1 or 10,000 crore litres of water, which is more than the city’s annual requirement, but 80 per cent of the same has not been conserved and gone down the drain due to absence of any harvesting facilities.
Given the horizontal expansion of cities where vacant land is being developed for housing layouts, ensuring water security is of critical importance and needs to be an in-built feature of the layout. On an average, for a housing layout of 100 people located on a two-hectare area, 40 lakh litres of water is needed annually and this two-hectare area receives on an average of 1,000 mm rainfall. Given this, efforts are needed to ensure conservation of at least 80 per cent of this rain water to recharge the ground water table and, thereby, ensure water security for the inhabitants.
In addition, rainwater harvesting can help conserve municipal water by reducing the amount of water needed for toilet flushing and outdoor watering. According to the estimates, less than three per cent of municipally-treated water is actually used for drinking. The rest goes down the toilet, washing cars or watering the gardens. The home-owners can employ usage of rain water for alternate applications and reduce their daily municipal water use by approximately 30 per cent.
Rainwater harvesting can also improve eco-system, health and reduce river and stream erosion by means of managing storm water runoff.
There are other benefits to rainwater usage as it contains none of the chlorine found in centralised municipal water supplies, and needs little, if any, purification or disinfection. The water is naturally soft, sodium and mineral-free making it ideal for bathing and washing. In addition it does not produce scale on appliances and eliminates the need for salt-producing, water-softening devices.
Although an exhaustive legislation is in place in India to further rainwater harvesting and its implementation but the same is rendered toothless due to erratic and half-hearted execution. In order to improve execution of rainwater harvesting, the Government can involve NGOs, especially for information gathering and awareness generation.
In many States, the incentives are limited to nominal rebates in property taxes and or subsidies in setting up the rainwater harvesting structures. The Government needs to plan much more imaginative incentives such as linking the benefit to discounted water and or electricity bill every month.
The impetus to popularise the concept on a nationwide basis would need far greater efforts on the part of the Government. In fact certain State Governments such as those of Tamil Nadu, Rajasthan and Maharashtra resort to penalties such as disconnection of water connection to the building that does not implement rainwater harvesting facilities.
Such stringent steps may seem retrograde in nature but are important to ensure proper implementation.