Pacific Island groundwater and future climates: First-pass regional vulnerability assessment

Project completed 2015

Background


Figure 1. Low Carbonate island:
Maiana atoll, Kiribati.
Photo courtesy of T. Falkland, 2014.

Islands in the Pacific region rely heavily on groundwater. For many Pacific islands, groundwater is the only reliable source of fresh water throughout the year. Sea-level rise and changes in rainfall patterns are likely to put water resources – already under pressure from increasing populations and pollution – at further risk, threatening the long-term viability of communities and islands.

Geoscience Australia completed a desktop analysis to better understand the vulnerability of fresh groundwater systems to future climates for 15 Pacific Island countries and territories including: Cook Islands, Federated States of Micronesia, Fiji, Kiribati, Nauru, Niue, Palau, Papua New Guinea, Republic of Marshall Islands, Samoa, Solomon Islands, Tonga, Tuvalu and Vanuatu. This study involved extensive consultation with Pacific Island groundwater hydrology experts. Where possible, this project has drawn on in-country expertise and consultation with the Applied Geoscience and Technology Division (SOPAC) of the Secretariat of the Pacific Community.


Figure 2. Volcanic island:
Rarotonga, Cook Islands.
Photo courtesy of T. Falkland, 2014.

This project forms part of the Australian Government's Pacific-Australia Climate Change Science and Adaptation Planning (PACCSAP) Program administered by the Department of the Environment.

Objectives

The objectives of this project were to:

  1. Support adaptation investment decisions in the Pacific region by developing a regionally consistent hydrogeological classification
  2. Assess the potential future climate impacts on groundwater for islands in the Pacific region
  3. Identify key regional data gaps and inconsistencies in the Pacific region relevant to hydrogeology.

Figure 3. Regional map of
hydrogeological island types
across the Pacific.

Outcomes

As part of this project, Geoscience Australia has developed a:

  1. Consistent approach for assessing groundwater potential vulnerability to low rainfall periods and sea-level rise across the Pacific region at an island scale.
  2. Hydrogeological typology for the Pacific region, with islands classified as: low-carbonate, limestone, volcanic, composite and complex island types.
  3. Regionally consistent spatial database of island hydrogeological and physical characteristics. These baseline data can be utilised and added to for future regional vulnerability assessments.

A key finding of this project is that low-carbonate islands are identified as the most vulnerable type of island to low rainfall periods and mean sea-level rises. Complex islands are the least vulnerable to both of these scenarios.

Outputs

Download the final report, figures and regional maps:

  1. Final report: Pacific Island Groundwater and Future Climates - First-Pass Regional Vulnerability Assessment
  2. Selected report figures
  3. Groundwater vulnerability to periods of low rainfall (2035-2064) (A0 Sheet 1)
  4. Groundwater vulnerability to periods of low rainfall (2070-2099) (A0 Sheet 2)
  5. Groundwater vulnerability to sea-level rise (2035-2064) (A0 Sheet 3)
  6. Groundwater vulnerability to sea-level rise (2070-2099) (A0 Sheet 4)
  7. Hydrogeological island types (Regional) (A0 Sheet 5)
  8. Hydrogeological island types (Country scale) (A0 Sheet 6)

Download the data package containing:

  1. Pacific Island Groundwater Vulnerability to Future Climates Dataset
  2. Pacific Island Groundwater Vulnerability to Future Climates Dataset: Data Dictionary
  3. Pacific Island Groundwater Vulnerability to Future Climates Dataset: Metadata