Mauritius Groundwater: The Hidden Risks of New Borehole Drilling

Mauritius relies heavily on groundwater to meet the needs of its population, agriculture, and industry. As surface water sources come under increasing pressure, new boreholes — deep wells drilled into underground aquifers — are being developed across the island. But water experts and environmental specialists are raising the alarm about the risks this expansion could bring if not carefully managed.

Aquifers are underground layers of rock or sediment that hold water. Mauritius has several key aquifer zones, particularly in the northern and coastal regions of the island. These reserves have taken thousands of years to accumulate and are not easily replenished. Over-extraction, or drilling in the wrong locations, can cause water tables to drop, meaning pumps must work harder and communities can lose access to clean water.

One of the most serious concerns is saltwater intrusion. In coastal areas, if groundwater is pumped out faster than it is naturally replenished by rainfall, seawater can seep into the aquifer and contaminate it with salt. Once this happens, the water becomes unusable for drinking or irrigation and the damage can be very difficult — sometimes impossible — to reverse.

There are also risks associated with the quality of drilling itself. Boreholes that are poorly constructed or inadequately sealed can act as a direct pathway for surface pollutants — including agricultural chemicals, industrial runoff, and sewage — to reach underground water reserves. Given that Mauritius has significant sugarcane farming activity and growing industrial zones, this is a real and present danger.

The Central Water Authority (CWA), the state body responsible for water supply and distribution in Mauritius, oversees licensing for borehole drilling. However, critics argue that oversight needs to be strengthened to keep pace with the growing number of private and public drilling projects across the island.

Climate change adds another layer of complexity. Mauritius has experienced increasingly erratic rainfall patterns in recent years, with longer dry spells reducing the natural recharge of aquifers. This makes sustainable management of groundwater even more critical, as the island can no longer rely on historically predictable rainfall to replenish what is extracted.

What this means: For ordinary Mauritians, the stakes are straightforward — groundwater feeds household taps, irrigates food crops, and supports industries that employ thousands of people. If aquifers are damaged through reckless drilling or over-extraction, the cost of finding alternative water sources would be enormous, and some communities — particularly in rural or coastal areas — could face serious shortages. Stronger regulation, proper environmental impact assessments before drilling begins, and public monitoring of water table levels are seen as essential steps to protect this hidden but vital resource.

Source: Le Defi Media