Water, water everywhere...........

I wrote this article some years ago but the main facts remain valid to date. The facts and figures are from various books published on rainwater harvesting by Centre for Science and Environment

I took over as XO, ------ towards the end of May 2001. Soon I found out that during get togethers, I was being cornered by quite a few of the lovely ladies of -------. However, it was more due to my inability to provide sufficient water than for my conversational skills. During the handing over, I had been told that there is an acute shortage of water in the Base and one of my main jobs during the tenure would be liaison with the Water department of the PWD to ensure that we got sufficient amount of water. I was told that everything possible has been tried and there was no solution to this shortage unless a new bigger pipeline from water pumping station was commissioned. However, I realized that a bigger pipeline is not a solution as PWD had only a limited supply of water and could not supply any more water to us.

This still left the problem of finding a source of water to alleviate the shortage. This led me to carry out some reading on water harvesting. The monsoons had commenced soon after my arrival at Goa and I found there was an enormous amount of rainwater available. It seemed criminal that in a place (Goa) which receives one of the highest average rainfalls in India (3005 mm compared to the national annual average of 1170 mm), there should be such an acute shortage of water. Compare this to the fact that if you had a hectare of land in barmer, one of India’s driest place, which receives only around 100 mm of water in a year, you could collect as much as one million litres of water. This is enough to meet the drinking and cooking water requirements of 182 people at 15 litres a day. Even if you are not able to catch all that water, you could , with rudimentary technology, capture at least half a million litres a year. Imagine then the amount of water available to us in our 250 acre campus with 3000 mm of annual rains (Rainwater calculator here).

However, there are a couple of things peculiar to rainwater.

-One, few of us realize the stupendous amount of water available to us because of the speed with which water, the most fluid of substance disappears. More so, In -----, an efficient drainage system ensures that the water drained out to sea as fast as possible. This gave no time for the water to seep into the ground and allow the groundwater table to be recharged. This was evident in the decreasing yield of our bore wells with some of them going dry.

-Two, it does not matter how much rain you get, if you do not capture it you will still be short of water. It is unbelievable but true that Cherrapunji which gets 11000 mm of annual rainfall, still suffers from serious drinking water shortage.

-Three, India receives most of its rainfall in just 100 hours out of 8760 hours in a year. If you don’t catch the water in these 100 hours, you will remain short of water.

-Four, the harvested water has to be stored for future use.

Even our ancestors recognized these facts and followed one of these means

-They harvested the rainwater directly by collecting water from rooftops, and stored in tankas built in the courtyards.

-Water collected from open community lands was stored in artificial wells called kundis.

-Harvested rainwater from monsoon runoff by capturing water from swollen streams during the monsoon and stored it in zings in ladakh, ahars in Bihar, johads in Rajasthan and eris in Tamil Nadu., to name a few.

Having got a glimpse of the enormous and undeniable potential of rainwater harvesting, I decided to work on it. I found that the rainwater drains had to be stopped and the flow of water had to be restricted to give it time to seep into the ground and recharge the groundwater. To ensure this, we stopped all the drains by building earthen dams across them by re directing the water to flow into sunken ponds excavated at couple of places. I am grateful to the members of the ship’s company who helped me in this exercise because it was an voluntary exercise and the excavation etc was done at the cost of a few thousand rupees.

With the first rain, a pond of 50 m by 50 m dug to a depth of six feet was full in the first hour of the rain and I had the pleasure of swimming in it. We found an abandoned bore well shaft and directed the excess water down that shaft. The water was allowed to seep into the ground. Although this would lead to recharging the ground water, no immediate benefit was available to ------ (At the end of the monsoon, the yield of the borewells was seen to be higher although we did not have any means to accurately calculate the yield). It was therefore decided to build concrete reservoirs to store the water and use it to supplement the Base’s water supply after suitable treatment (Never managed to finish this project. Actually couldn’t manage to start it also as I was transferred soon thereafter)

However, what we did manage was to collect roof water at Dhobi ghat as all the essentials like storage tank and filtration unit were available there. Eaves gutter and the pipes were fitted and it was found that during the monsoons, the water tanks at Dhobi ghat were always overflowing. A similar project was carried out in CO’s residence – ------ House where the rainwater was collected in a 25000 l ground tank and thereafter pumped to one of the bathrooms (Hampi, if you are reading this, now you know why you have rainwater in your bathroom, at least during monsoons)