Rain harvesting the only way out

MUCH TIME AND EFFORT ARE wasted in this country discussing human rights. Only a little of that time is spent discussing the most basic of human needs – water.

When it is discussed, it is usually on the basis that someone is failing to deliver properly. However, I wish to take a different approach,
My inspiration comes from a study done in Chicago, USA, 45 years ago. When asked, most school children did not know that milk comes from a cow. They thought it was a manufactured product sold in a supermarket. They had never seen a cow.

Where does water come from? We all know it just falls out of the sky. If it is underground, it only got there because it fell out of the sky and seeped into the rocks. Take it out faster than it seeps back and there is no water left underground. If our water is to come out of a tap, we have to collect it somehow.

Many Kenyans living in Central and Western provinces may not realise that their annual rainfall is, in fact, pretty much the same as the wettest parts of the UK or Ireland, areas of the world with no water shortfall.

The difference is that there, it rains on many days a year whereas in Kenya the rain comes in two great dollops each year, and most just runs into the ground or down the rivers and into the ocean.

It seems obvious – in Kenya we need to harvest the rainfall and use the water when it is not raining. That means, of course, rectifying the problem of deforestation of the water catchments.

It is an intractable problem which only has either a draconian or a very long-term solution because you have to forcibly remove up to a million people who were given the land by previous governments, and plant a billion trees which take at least 20 years to grow.

However, I am also entitled to ask: Is there anything I can do myself? The answer is a resounding “Yes”. I can easily collect all the rain God sends to fall on my roof. Of course that poses problems – but it also gives opportunities for the enterprising ones among us to find solutions.

THE COLONIAL BRITISH CREATED building regulations to stop people in Nairobi collecting their rainwater from roofs. The reason was that Nairobi (then a swampy area) suffered badly from mosquitoes and Nairobi eye beetles, which bred in the water tanks, and loved feeding on the rotting leaves in the tanks.

The city had a population of only 200,000 and the civic water supply was more than adequate for the city’s needs, so solutions to the insect problem did not need to be found – a good solution was to eliminate the water tanks.

Now the city has a population of three million, perhaps more. The civic water supply is still the same – more than enough for 200,000 people, but woefully inadequate for three million.

Nairobi has a rainfall of 1,000mm a year, but it still officially demands that the rain water falling on the buildings goes to waste. Nobody changed the regulations or asked the question: “How do we stop insects breeding in the tanks and prevent the leaves getting into the tanks and causing the water to go foul?”

For a property with a roof of 100 square metres (say a two-bedroom bungalow) one needs a tank size of about 60 cubic metres (60,000 litres) to collect all the rainwater. Considering that there are two rain seasons a year, how long does 60,000 litres last?

Most families consume around 300 litres a day. That is 200 days supply. So given two normal rain seasons a year, a family can collect enough rainwater for its entire supply.

Why not make a grant system available and require every property owner in Nairobi to install properly designed and approved rainwater harvesting gutters and tanks over a five-year period?