BY PETER MAKWANYA
Recently, Zimbabwe has been experiencing heavy downpours in most parts of the country. The rains have come as a blessing to the rain-starved citizens including the dry areas that had gone for years without normal rainfall. The incessant rains could have escaped many people’s rain-water harvesting techniques, but have gone a long way in replenishing the underground water reserves.
Underground water reserves have a special place in sustainable development, especially in a changing climate where the absence of reliable rainfall patterns have resulted in water scarcity throughout the country. Although the seepage of large amounts of run-off water differs with the nature and make-up of landscapes, there are telling signs that most underground water reservoirs have been sustainably and sufficiently fed. The boosting of the underground water reserves reduces water-related conflicts at community or national levels, thereby normalising and mending human relations. In the face of climate change, water security and food security are guaranteed.
Underground water reserves are estimated to hold more quantities of water than water stored on the surface of the earth. These are fresh water sources flowing beneath the rocks and sediments underground. In rural communities, these underground water sources readily provide fresh water which can be tapped for sustainable gardening, small-scale irrigation and a wide range of household uses.
These are necessary interventions to fight water scarcity in the face of climate change. As the earth continues to warm with increasing intensity, surface water is normally lost due to evaporation, overuse through small and large-scale irrigation, including brick-moulding and expansion of human settlements.
Wild and domestic animals also need this precious liquid in large quantities in order to survive.
Underground water reserves which can be accessed through digging wells, drilling boreholes and springs have dominated human livelihoods in the face of climate change.
The reliability of underground water is that it is usually found anywhere underground except for a few areas beneath the earth surface.
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Many underground water sources have high quality water reserves that humans can depend on as climate change impacts negatively on the reliability of water supplies on the earth’s surface. More fresh water is drawn from underground to support a wide range of human activities, the rising population and irrigation.
In the context of climate change, fresh water on the surface disappears or gets depleted. The only certain and reliable water in the face of limited precipitations and high evaporation is underground water.
In the face of climate change-driven heat waves, trees lose leaves and the shed that used to provide the cooling effect on ponds and support aquatic creatures like frogs, reptiles, birds and animals is also gone, leaving them exposed and vulnerable.
As the impacts of climate change are felt, with many communities focusing their attention on underground water reserves, their water tables can also decrease. Although we are not clear about the quantities of underground water, even faced with overexploitation, these resources remain the people’s only hope.
The amount of water stored underground varies from place to place depending on the climate and geological make-up. Underground water sources also need to be recharged and replenished through seasonal precipitations.
They are also naturally discharged through the flowing of ground water springs, streams, wetlands and sea evaporations.
Therefore, even in its abundance, underground water needs to be protected and conserved. The withdrawals people make through irrigation or human consumption also contribute to reducing the amount of water stored underground.
In the wetter regions of Zimbabwe, both underground and surface water is mostly replenished by large amounts of rainfall and rain-water seeping down through the soil to the watertable, occurring consistently over large areas.
In dry regions, underground water is mostly charged locally by water leaking into the ground from temporary streams and ponds, which only flow after particularly heavy rains. Therefore, the leaking of streams and ponds contributes to underground water in many vital ways.
The effects of global warming are reducing the amount of rainfall, but heavy downpours could actually be good for increasing ground water recharge overally.
Heavy rainfall and floods, resulting from weather patterns such as El-Nino or La Nina can boost underground reserves significantly in the face of climate change.
These heavy downpours are usually captured through flooding and stored underground where water can later be withdrawn for human consumption and irrigation during the dry seasons or years of droughts.
Sometimes, pumping more underground water can create room to accommodate greater seasonal recharges needed to boost the watertable.
After the country received massive amounts of rainfall, it doesn’t mean that water use restraint, stewardship and conservation should not be practised.
The culture of conserving water should be practised so that communities have enough reserves even in the face of global warming. Surface water should always be safeguarded for sustainable development ecosystemic protection despite that there is underground water as plan B.
Safeguarding also includes discouraging human practices like contaminating water through industrial chemicals that also affect underground water reserves.
Groundwater sources and the boosted ecosystems work hand-in-hand. If groundwater is polluted the ecosystems will be compromised.
The wetlands, forest vegetation, aquifers, flora and fauna need to be safeguarded so that underground water reserves remain safe and uncontaminated.
Forests and vegetation withdraw large amounts of water for moisture preservation from underground water sources, vital in the establishment of carbon sinks to store large amounts of carbon underground to fight climate change.
- Peter Makwanya is a climate change communicator. He writes in his personal capacity.
