Novel applications of isotope hydrology for sustainable water resource management in small islands

?
Small island states are among the most hydrologically vulnerable regions globally, facing escalating threats to freshwater availability and quality as a consequence of climate change. The combination of limited land area, the accelerated hydrological cycling, complex geological formations, and restricted aquifer capacity contributes to a heightened sensitivity to extreme meteorological events. These factors pose significant challenges to the accurate assessment and sustainable management of water resources.?This research initiative introduces a dual isotope hydrology framework aimed at addressing critical data limitations that currently constrain vulnerability assessments in island environments. Integrated stable isotope studies have demonstrated that stormwater infiltration can substantially reorganize aquifer isotopic signatures, thereby revealing latent vulnerabilities in groundwater systems. Despite these advances, the diverse hydrological regimes of island states are not yet adequately characterized. Resolving this requires addressing the main constraint in the limitations of traditional stables isotopes, that while highly effective for identifying water sources, cannot independently resolve the timescales of water movement.?To overcome this limitation, this CRP proposes a dual integrated isotope study that combines traditional stable isotope tracers of water, specifically δ18O and δ2H, with the application of the short-lived radionuclide 35S. This integrative approach enables the temporal resolution of recent recharge events and facilitates the identification of aquifer responses to storm activity. Through this approach, the CRP aims to address key data gaps, advance the understanding of groundwater recharge dynamics, and contaminant transport mechanisms under conditions of climatic stress in island contexts. The insights generated will inform the development of scientifically robust strategies for enhancing water security in small island states.