It is important to design systems holistically connecting the whole hydrological cycle and link it to urban water needs, feels water expert S. Vishwanath
As we enter an era of higher water demand our ways of managing water have necessarily to adapt to the new situation. The utility that supplies piped water to Bangalore has recently been nominated for a national award for its role in adopting and promoting rainwater harvesting in a major way.
The city utility has come to the conclusion that depending on piped water supply from a single source is simply not sufficient. Multiple sourcing and management of water is the order of the day. Rainwater harvesting is seen as one additional way of supplementing the water requirements of the city as well as recharge the aquifers from where many source their water.
Water and sanitation utility institutions have to morph themselves into water managers from water providers. Skill-sets within the institution will no longer be limited to civil engineering but will call upon hydro-geologists, social community workers, legal advisers, hydrologists, waste water recycling specialists, public health specialists and ecologists.
Urban water has to be placed in the broader water and nutrient cycles. The monsoons are coming to an end in another month in this part of the world. They have by and large filled up all the large and many of the small dams on the rivers. That is good news especially for energy generation and for agriculture. Have they filled the numerous tanks and lakes in the basins from where the city draws water? Have they filled the urban tanks and lakes for the water to last another six months to a year? Have they filled the aquifers in the city where numerous wells and borewells will pump water out in summer?
Left derelict and unmanaged, most of the tanks and the aquifers will stay unfilled; if de-silted and with channels cleaned, they will fill up. The key therefore is to design systems holistically connecting the whole hydrological cycle and link it to the urban water cycle.
Aquifers are great water banks below our feet. They can be best compared to sponges capable of holding lots of water. By paving the city we deprive them of their ability to fill up during the rains. Only by de-silting and then ensuring that our lakes fill with storm-water and by adopting scientific rainwater harvesting for artificial recharge can we allow water into the voids and cracks in the earth.
This multiple understanding and management of water also happens at lower units of the city such as in apartments or in neighbourhoods and sometimes even in individual homes. Water knowledge/water literacy therefore becomes a skill-set that society has to value in future.
While the environmental aspect of water needs knowledge the social aspect of it cannot be denied. Society must ensure that universal access to water and sanitation, especially by the socially and economically vulnerable sections, is high on the priority list of our planners and managers.
It is in a time of relative abundance that planning is most needed but unfortunately it is at this time that one is most complacent. While “making hay when the sun shines” is an old proverb, “harvest water when it rains” is a newer and much needed one in modern times. In this multi-disciplinary and participative approach lies water salvation, and that is water wisdom.
Keywords: Rainwater harvesting