columnBy Edward Byrne
You might or might not know that many boreholes in Harare have either run dry completely or will only pump for short periods at a time. This is undoubtedly a result of so many boreholes being drilled over the past few years as well as the irresponsible usage of borehole water.
The water table has fallen to disastrous levels and is still falling. Ultimately all boreholes will either run dry completely or only produce water for short periods of time with a long recovery period before flow is resumed.
The water table is replenished only by rainfall and this replenishment commences from the level of the water table at the onset of the rains. If one assumes continual normal rainy seasons (and this is a big assumption) and a continuously falling water table due to excessive off-take, even the replenished level will fall from year to year. If evidence is required that the water table is falling continuously consider this:
My borehole ran dry for the first time in November 2008. In 2009 it happened in October, 2010 in September and August in 2011. Before 2008 it was a prolific borehole.
In simple terms demand is ever increasing while supply remains static. Because of this, we all need to take a fresh look at how we use borehole water.
Many people are still maintaining emerald-green lawns despite this dire situation; some are even maintaing their vegetable gardens. This is a luxury that none of us can afford. Watering of lawns and vegetables accounts for approximately 90% of borehole water usage.
For those fortunate enough to still have sufficient water to keep lawns and gardens green, and who utilise that capacity, it is only a matter of time before their boreholes start to deliver water sporadically or not at all.
Remember, those of us with marginal or dry boreholes are paying the price for your profligate use of this precious commodity. None of us get municipal water with any regularity (if at all) and all of us rely on our boreholes or bought water for our domestic requirements,
If evidence of the effect that watering of lawns has on the water table is required, consider this: At midnight (when nobody is irrigating their lawn) my borehole will pump water continuously for 10 minutes. At midday when the sprays are out in force my borehole will produce water for only three minutes.
As a community, the time has come to take concerted action to conserve this precious resource. With concerted action the water table can recover.
I am presenting a short list of suggestions which I hope we can all follow.
Stop watering lawns and vegetable gardens immediately. Remember watering lawns and vegetables is 90% of the problem.
Consider changing your lawn grass from the broad bladed (Durban, Buffalo, Kikuyu) water thirsty grasses to a narrow bladed evergreen.
This will go brown in winter and recover instantly at the onset of the rains. This is after all the natural cycle in Africa.
Water your vegetable garden and flower beds from a watering can.
Wash your car from a bucket.
I hope everyone will give thse recommendation serious consideration and act upon them. For those who have already made this decision, well done and thank you.
I appeal to everyone to please help to spread this message. Once the majority have accepted the necessity of this course of action the rest will follow. The water table can recover but only if everyone plays their part.