Tunis:If it were up to me, I would stop building dams and let water resume its natural cycle,” said Dr Raoudha Gafrej, an international expert and consultant on integrated water resources management and climate change adaptation.
“The storage of surface water must not be at the expense of the recharge of the groundwater table, and humans must not deprive other plant and animal species of their right to fresh water,” explained the scientist, who advocated, in an interview with TAP TV respect for the natural water cycle.
For Gafrej, not retaining rainwater does not mean losing water; on the contrary, it favours the recharging of aquifers, thereby restoring the water cycle and renewing groundwater reserves. “This helps to reduce flooding, combat erosion and, of course, provide more water during hot periods by recharging the water table during periods of heavy rainfall”.
Gafrej believes we should be more concerned about the state of groundwater, which, once over-exploited, is very slow to replenish, if at all.
Surface water is provided naturally, in stable quantities on Earth, thanks to a perfect natural cycle. The Earth has received the same amount of water since its creation. What has changed with climate change is the distribution of this water among the continents.
The run-off water must be allowed to resume its course to replenish the water table, which is the largest reservoir of fresh water on Earth, because a drop in its level could jeopardise food security, basic water supplies and resilience to climate change,” she pointed out. She condemned the uncontrolled drilling of deep wells, the number of which has reached 30,000 in Tunisia.
On the issue of climate change, Gafrej stressed the importance of run-off water for marine ecosystems, photosynthesis and food security.
On another level, the expert pointed out that allowing runoff to find its way into the oceans can only be beneficial for people and biodiversity.
“This water is vital because it carries the mineral salts needed by phytoplankton, the micros
copic algae responsible for photosynthesis in the ocean, as produced by vegetation on land.
These marine organisms are at the base of the food chain for fish, marine mammals and shellfish. They also produce large quantities of oxygen, which dissolves in the water and then finds its way into the air we breathe thanks to the exchange of gases between the ocean and the atmosphere.
“Almost 50% of the oxygen we breathe is produced by phytoplankton, which also absorb around 25% of atmospheric and anthropogenic CO2 (due to human activity),” says Gafrej, explaining the importance of these organisms for life on Earth and their dependence on the water that circulates around the planet.
According to scientists, marine phytoplankton fix as much CO2 from the atmosphere as all terrestrial plants, and are therefore vital in reducing the greenhouse effect and rising temperatures caused by human activity.
Source: Agence Tunis Afrique Presse