Climate and Abstraction Impacts on Atoll environments

The CAIA project aims to improve the understanding of climate variations and human impacts on atoll groundwater resources and identify technical and practical management tools that can be used by Government and communities to strengthen water security.

Small Island Resources

Small island atoll states have limited and vulnerable groundwater resources. With the CAIA project, groundwater resources will be assessed in two different atoll environments, Bonriki in Kiribati and Vaitupu in Tuvalu, using hydrogeological investigations techniques and groundwater modelling.

 

Assessment

The assessment of these resources coupled with the development of a sustainable yield concept for a freshwater lens under predicted climate and abstraction pressures will improve the resilience of Pacific Islands Communities in the future.

 

Freshwater Lens

The groundwater on atolls is often described as a ‘lens’ of freshwater ‘floating’ on more dense brackish water. This very thin and fragile freshwater resource relies on being regularly recharged by rainfall. Concerns over the salinisation of these fragile water sources due to rises in sea level, changes in climate variability and extremes, and human activities are increasingly raised by atoll communities and governments.

Threats to Groundwater 

Whilst rises in sea level pose a longer term threat to freshwater lenses, the more immediate threats are from over abstraction and inappropriate land use activities, including poor sanitation practices, intensive cropping or animal husbandry in unsuitable locations. It is expected that population pressure and climate impacts will place the limited groundwater resources of atoll countries under an ever increasing threat.