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January 17, 2019

All that rain does not make hydro-geologists happy

For many town dwellers, the rains — apart from the initial showers that cool the air, get rid of the dust — are a nuisance. Even the threat of rain is enough to create mild panic. A society which never thinks much of the next person turns to total ‘me thinking’ when the skies open up. The thoughts are either I need to be elsewhere or there is money to be made here. From newspaper vendors to malls, as people opt to go home early or stay in their cars on the road rather than window shop and have coffee the rains are a loss. There are a few who gain though. You cannot risk having only Sh100 worth of petrol in your car and end up in a traffic gridlock. Public transport also often raise charges. The problem with this kind of thinking is that it is all short term. We cannot wait for the rains to end, so that we can continue with whatever we usually do. What many do not realise is that there has been a fundamental shift in the way the rains and other elements of the weather that make up our climate has changed

Between 1900 and 1930, the average rainfall in November month was 82.8mm; between 1990 and 2012 this average had risen to 95.8mm. Whereas historically April has been the wettest month followed by May then November, since 1990, November has edged out May to become the second wettest month. While we still imagine that the period October to December are the ‘short rains’, the reality is that there may soon be more rains in the ‘short rainy season’ than the ‘long rainy season’.

For a country that has a net deficit of water, this may sound like finally someone has answered our prayers, but it is not that simple. In order to benefit from the rain we have to manage the water well and think through where the water ends up and how we use it.

Because of gravity and other laws of physics, rain falls into the ground, and without much prompting finds its way either underground or to the ocean. As a stream or a river, there is now much regulation of what you can or cannot do with the resource and from a health perspective, the benefits and dangers of fast moving water are easy to see. It is the water that seeps into the ground around us that is a little harder to understand. Beneath the top layer of all soil are rock formations of various types. Any water will percolate between the soil spaces into these rock formations where if sufficient amounts collate then an aquifer, a usable deposit of water is created. Hydro-geologists, scientists who study rock formations in relation to water, get very excited when they find aquifers. But it is rare to find a group of very excited hydro-geologists, because around the world most of the largest aquifers in the world are in retreat, shrinking as man uses up water at a rate more than it is being replenished. Kenya being part of Africa is always in a worse condition than the world average, given that to start with we had less.

From a health perspective the implications are grave. The study of water is critical because there are many diseases that are associated with water. For healthy lives, we require just enough water, not too little, which leads to problems with hygiene, or too much when water becomes a conduit for disease to move quickly from person to person. Where the hydro-geologists meet the doctor is when the ground that holds the water becomes the home where diseases lurk waiting to attack. This is what happens at the onset of the rains and continues as the skies open up. The water table rises, that is, water held by the soils begin to rise closer to the surface. This is fine if you are a farmer and want to plant crops; but not a good thing when you live a slum where pit latrines are everywhere. The water table can rise to the point where the pit latrines are essentially floating on water. For any worms, parasites, bacteria and viruses that might have been contained by dry surroundings of a pit latrine, the rains provide little rivers where they can float to the surface or across contaminating wells, poorly maintained pipes carrying drinking water. A lot of rains then become a health issue especially in urban areas where not a lot of planning to promote health goes on. Where many people live with poor sanitation rain can become a curse, yet they need clean water to wash away disease. The solution to such problems is for doctors in public health, engineers and hydro-geologists to work together mapping out where the risks are highest and what should be done.


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