Wednesday, March 09, 2016

Collecting rainwater at the family level

There was a time when water cost nothing, but now a large number of families in India pay for the piped water they use. Many of those who do not get piped water pay a lot more for tanker water, which is usually of uncertain quality. Piped water costs as much as Rs 35 per kiloliter in some urban areas. Many families pay as much as a few hundred rupees a month to get water. Under these circumstances, it is logical to think of collecting rainwater for individual families. There is a lot of information on the Web. Visit
The first one is about water collection from a tiled roof in Mangalore. The second is about water collection in Africa. The following article provides additional information.
I would like to focus the rest of this post on drinking water. Water borne diseases continue to be a major problem in India and are the cause of avoidably high infant death rate. India receives an average of about 1 meter of rainfall annually. If we had a funnel with a collecting area of about 1 square meter, we could collect a thousand litres of water a year. How much drinking water do we need? The following article refers to an Indian Standard (BIS 1172, reaffirmed in 1998) which is reported to say that the requirement (per person per day) of drinking water is 5 liters per day, in addition to 5 more liters for cooking.
I can do with a lot less of drinking water per day; I would think of two litres of drinking water per day per person is a reasonable design assumption. Keeping the collecting equipment and the collected water free of dust and other contamination is very important. A few cubic meters of water are what we need to collect and store; doing this at an affordable cost requires a fair amount of trial and error. The challenge is not unsurmountable. A country which has a million students starting engineering college every year can very well meet this challenge. We need to create a good product design leading to local manufacture and to the solution of a vexing problem.

No comments: