Disasters in the Pacific cause average annual direct losses of over US$200 million, spread over a combined population of less than 10 million people, making this region extremely vulnerable to hazards and climate change. Ecosystem-based adaptation (EbA) uses a multi-sector/multi-scale approach to reduce vulnerability to natural hazards, to bolster ecosystem services, and to protect biodiversity through sustainably managing ecosystems. Evidence from developed countries shows that EbA can be more cost effective than infrastructure in reducing risk, making it attractive for developing countries with limited resources. However, (EbA) has been underutilised and understudied in the Pacific.

In the wake of two major flood events and a cyclone in 2012, this research project conducted an assessment of disaster risk reduction actions for flooding in the Ba and Penang River catchments in Viti Levu, Fiji to identify the most cost-effective management options for communities and households. The analysis accounted for the biophysical and socioeconomic impacts of flooding, the costs, benefits, and feasibility of management, and the potential impacts of climate change.

At the foundation of this study was an extensive socioeconomic survey that quantified the direct and indirect costs of flooding in the Ba River and Penang River catchments. In addition to estimated damages, this survey found that crop damages accounted for over 80% of the total damages recorded. The researchers developed hydrological models of the two river catchments to forecast future flood damages and to evaluate the effect of infrastructure development and ecosystem-based adaptation on future flood damage. Next, the project team incorporated likely impacts from climate change, before conducting a comprehensive cost-benefit analysis (CBA) to systematically assess adaptation options.

In the course of this research, local practitioners were trained in research methods and data interpretation to build capacity and promote sustainability. Among the outputs of this project is a CBA framework to support decision makers to consider ecological and social resilience in policy and planning. The full results of the evaluation of EbA for disaster risk reduction in Fiji are available in the final report.

Results

According to this research, annual losses from flooding will increase by an estimated 90% with moderate climate change and by nearly 275% with severe climate change, by 2090. For perspective, damages from a 1-in-50 year flood, which is the estimated return period of the January 2012 event, are projected to cause between FJ$76.5 and FJ$153 million in damages in the Ba River Catchment under these two scenarios. There is clear need for investment in adaptation and disaster risk reduction measures.

Communities can take hard, soft, and ecosystem-based approaches (EbA) to reduce flood-related disaster risk. For EbA, these mitigation options include planting riparian buffers, afforesting the upper catchment, and planting floodplain vegetation. Hard options include reinforcing riverbanks, dredging rivers, and raising houses.

The cost-benefit analysis revealed that while not all EbA interventions offer good value for money, such approaches often produce greater net benefits than hard options, particularly when accounting for climate change. Upland afforestation typically provides the greatest benefits overall because trees not only reduce the damages from flooding but also produce large quantities of monetised ecosystem services such as fruits, firewood, and carbon sequestration. Riparian planting does not provide the highest level of protection from flooding, but the low cost of implementation coupled with the ecosystem services means that it has the highest impact per dollar spent on mitigation. The benefits of river dredging exceed the costs under the moderate and extreme climate-change scenarios; however, the cost of re-dredging on a frequent basis is high relative to the benefits, particularly in the Ba River catchment. Neither reinforcing riverbanks nor raising houses was found to be economically viable in the two study catchments.

Outcomes

This work has led to greater understanding and use of ecosystem-based adaptation, and increased use of cost-benefit analysis in options analysis for climate change adaptation in Fiji. For example the major regional Coral Triangle Initiative is now promoting EbA as well as the Fiji government (ICM) and Wildlife Conservation Society in Melanesia, partly due to the influence of this work. Some of the suggested EbA options (e.g. afforestation) are already being implemented in the Ba and Penang river catchments. Training and use of CBA has been increasing in the region, including through this project, and the CBA Guide has been an integral part of these trainings. The CBA framework developed in this project and set out in the CBA Guide (see below) has already been utilised by a US$4 million USAID project on disaster risk reduction and climate change adaptation in nine Pacific countries.

While it is too early to assess the benefit of risk reduction and measures implemented during the lifetime of this project, that a Ba flood in February 2014 resulted in less than expected damage is a positive sign.

The project team area now exploring options for applying the framework developed under this project to other sites in Fiji and Solomon Islands, and to trial a rapid assessment approach.

Resources

Evaluating Ecosystem-Based Adaptation for Disaster Risk Reduction in Fiji - Full report and executive summary

A Guide to Cost-Benefit Analysis for Natural Resource Management in the Pacific. There is a wide variety of guides and manuals on CBA across the globe. However, up to now there has been no guide that brings together the steps of CBA with an emphasis on the Pacific region. This guide fills that gap. It aims to support Pacific government and non-governmental organisations in their CBA activities, and to support training and capacity development in this area. The guide is also intended to standardise approaches to CBA by the agencies involved − SPC, SPREP, PIFS, USP, GIZ, UNDP − so that practitioners receive consistent advice and support. The Guide was developed in partnership with the Secretariat of the Pacific Environment Programme (SPREP), and it has been used as a manual for economic analysis training in several Pacific islands.

To date, two academic papers have been produced by this project and submitted to journals, on the following topics:

• Assessing Adaptive Capacity In Pacific Island Communities: The 'Pacific Adaptive Capacity Analysis Framework'
• Economic Impacts Of Climate Change On Flooding In Fiji

CDKN funding: £318,000

Lead: University of South Pacific, Fiji; Prof. Bill Aalbersberg and Dr. Dan Orcherton

Partners: Adam Daigneault and Suzie Greenhalgh, Land care Research, New Zealand.