– Source:Mauritius’s water supplies are running very low. As a small island, it is affected by tropical cyclones, rising temperatures, rising sea levels, and a warming ocean. Rainfall levels have decreased by 8% over the last 10 years.
The country’s reservoirs are currently only about 38.2% full, down from 92.6% in February 2024. The population has increased from 479,000 in the 1950s to over 1.26 million in 2022. The bigger demand for water has placed pressure on already strained resources.
Droughts in Mauritius are predicted to become more severe and frequent. This will trigger serious water shortages that will disrupt farming and affect the livelihoods and wellbeing of local communities. The current water shortages have already affected big water users – business, industry and agriculture – in the central plateau and coastal regions.
These problems are part of a broader trend across small island developing states. Mauritius has put in place stringent restrictions against using water to wash cars, pavements or buildings, or to water gardens or fill swimming pools. There are fines of 50,000 Mauritian rupees (US$1,162) to 200,000 rupees (around US$4,653) for people who do not comply.
Irrigating sugar cane has also been suspended, even though this is vital for the island’s economy.
However, these restrictions won’t be enough to solve the water shortages. We are part of a team of researchers from Mauritius, France, the United States and Kenya. In Mauritius, we’ve researched ways that the country can adapt its water systems to climate change.
We looked into whether it would be helpful to capture river runoff – water from rivers that flows into the sea when it rains. We identified water-stressed areas, rivers, settlements, and the elevation and slope of land across the island. We then combined this information with an analysis of rainfall trends over 89 years (from 1931-2020) and other factors.
Our research recommends that the government build 10 reservoirs in places where they can harness natural water flows. These could in total store 500,000 cubic metres of water which would supply people during dry times.
Although this is about two days’ worth of the current amount of water used, during severe water shortages, if water restrictions were also put in place, the reservoirs would provide a useful amount to tide people over.
Rainwater wastage on small islands
Small tropical islands like Mauritius mostly rely on rivers, streams and groundwater for their water supplies. But pumping too much groundwater out through boreholes can deplete it. Water infrastructure is also old and in 2020 alone, 60% of water was lost from leaking pipes.
Water is often supplied to drought stricken areas by water trucks. But this is very costly and the trucks can’t carry enough water to meet everyone’s needs. It’s not a permanent solution.
On the other hand, when it rains on small islands, rivers get full fast and much of the rainwater is wasted by flowing into the sea. Mini reservoirs strategically located all over Mauritius could capture seasonal peak river flows.
Based on our local knowledge of the pricing for the construction of such mini reservoir systems, we estimate that ten of these would cost about US$100 million. This is a large amount for a small island nation, but the reservoirs would help the country during the dry months. Having more reservoirs dotted throughout the country would also make water systems easier to manage.
What needs to happen next
Our research highlights that Mauritius must move fast and use several different approaches to bolster its water security.
First, we recommend that the government of Mauritius should look into blended finance to raise the money needed for the reservoirs. For example, it could get public concessional funding from entities like the Green Climate Fund, where part of the finance is a loan and part is a grant that does not need to be repaid.
The Mauritius government could also look for technical assistance and co-financing arrangements from multilateral institutions such as regional development banks.
Using solutions inspired by nature and involving communities can help to build long-term resilience to drought. For example, if community members get together to clean up and restore wetlands, this will help the soil retain more water when it rains. Growing urban forests can also help.
In built-up areas, water-sensitive urban design, such as green roofs, permeable pavements and rain gardens, can help water soak into the ground to refill underground aquifers.
Working with local communities to save water at home is key, because homes in Mauritius are where most water is used. For example, leaking water pipes are a prominent issue in ageing water systems that haven’t been upgraded. Fixing leaks and community-led water conservation initiatives can save large amounts of water.
The government of Mauritius needs to set up policies that enable partnerships with the private sector. Grant funding from international climate initiatives should be combined with investment from the private sector to adapt the country’s water systems. For example, raising the height of the country’s dam so that it can store more water needs to be investigated.
In densely populated urban centres like Port Louis, it is critical to install smart water management technologies. These include smart water meters that prevent water waste by transmitting information about water levels and leaks to a water utility, and remote sensing and geographic information systems that monitor how much water is being used, and where it’s being wasted.
These, and infrastructure upgrades like replacing old and leaking pipes and expanding rainwater harvesting networks, can cut a lot of wastage.
Coping with escalating drought crises in small island developing states demands a blend of innovative infrastructure development, solutions that are based in nature (like rainwater harvesting), the support and active involvement of local communities, and strong governance.
By fostering international collaboration and support, these vulnerable regions can build greater resilience and secure a sustainable water future.
The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.
By Jay Doorga, Lecturer, Université des Mascareignes (UdM) And
Natalie Sum Yue Chung, PhD Candidate, Center for Policy Research on Energy and the Environment, Princeton University
