Adaptive water management in small Islands amidst climate change: addressing drought and Harnessing river runoff in Mauritius

Small islands have long been considered as one of the most drought fragile regions. Analysis of rainfall trends from 1931 to 2020 in Mauritius reveals a significant decline in rainfall, reducing surface and aquifer recharge by up to 22.3% and 24.7%, respectively. This decline, coupled with rising water consumption driven by economic growth and significant distribution losses, has stressed the island's water supply system, causing shortages during some summer months. To enhance resilience, the construction of mini dams and off-channel mini reservoirs are proposed near identified water stress areas to capture water lost to the sea, increasing the water stock capacity by 0.5 Mm3. A Multi-Criteria Decision Making-Analytic Hierarchy Process (MCDM-AHP) model guides the identification of priority areas for these reservoirs. For long-term water resource management, governance, economic, nature-based, legal, and engineering strategies are suggested to ensure sustainability and efficiency. These interventions aim to mitigate the impacts of declining rainfall and rising demand, ensuring a more resilient water supply system for Mauritius.