Water: Let’s not duck our responsibilities

Originally posted on October 21, 2016


With the North East monsoon starting, it would be a good time to reflect again on water and we hope it would not be like the cliché of pouring water on a duck’s back. President Maithripala Sirisena disclosed this week that while about 40% of Sri Lanka’s people did not have access to fresh drinking water, a shocking reality was that in cities and urban areas about 45% of the fresh water supplies were being wasted. The President assured that with hundreds of millions of rupees being allocated for irrigation and fresh water projects all the people would have access to fresh water within two years.

While we hope for showers of blessings on this mission we need to consider ways in which we could help save fresh water because world experts have predicted that within the next few decades many countries would face major shortages of fresh water and may even go to war to gain control of supplies, as they did in Afghanistan and Iraq to gain control of fossil fuel supplies.

Sri Lanka has been blessed with 16 major rivers in addition to canals and streams. But besides wasting fresh water supplied on taps we have been polluting some of our rivers with industrial companies being among the main offenders.

Just as little drops of water make the mighty ocean every eco-friendly citizen or family could make a contribution towards saving water which is essential for life, for instance while washing our hands or utensils we need not open the tap fully but halfway or less. We could also cut down on our shower bath time by about five minutes. Water used for washing food items could be collected in pans and used to water the plants. If each eco-friendly citizen could save about 10 litres of fresh water daily then thousand citizens would be saving 10,000 litres and 10,000 citizens could save 100,000 litres.

Some enterprising citizens have gone to the extent of installing equipment for rain water harvesting. Yesterday the Daily Mirror published an article by a veteran agriculture academic Dr. C.S. Weeratne on “Rainwater Harvesting” and how the world relied on it for centuries. According to him and Sociologist Prof. Siri Hettige rain is the primary source of water. The mean annual rainfall in the south-west of the island varies from 2,500 to 5,000 mm, and in the north-west and south-east, it is around 1,250 mm. Some of the rainwater goes into the soil. Depending on the nature of the soil surface and its depth, a portion of this water is retained in the soil, and the rest percolates down into the ground water. The water that does not percolate runs off and enters water bodies such as lakes, rivers and reservoirs

Dr. Weeraratne says Sri Lanka receives around 100 billion cubic metres of rain and around 40% of it runs-off. Around 35% of the run-off is used for irrigation and generation of hydro-power and the balance which is about 65% of the run-off escapes to the sea. Thus, nearly 26 billion cubic metres of water is wasted.

Water that falls on a roof of 1,000 sq. metres in Colombo (average rainfall is 2,000 mm), during one year would be around 2,000 cubic meters. The actual cost of this amount of water would be around Rs.90,000. The rainwater that falls on the roofs of extensive buildings such as hospitals, schools, and housing complexes could be collected in tanks in the premises itself. Water thus collected could be used for numerous domestic purposes. Instead of using chlorinated water suitable for drinking to wash vehicles, water plants and clean toilets, using rainwater for these activities would reduce water bills and save purified water, which could be used for drinking purposes. Once the collection system is installed there is no additional cost involved except on pumping of collected water to the main water supply system.  So let us save water before one we might have to say, we do not have even a drop to drink.

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