Source: UNISDR Disaster Risk Reduction
When an underwater volcano erupted about 65 kilometres north of Tonga’s main island, Tongatapu, in January 2022, it sent ash high into the atmosphere and triggered a tsunami that struck the archipelago nation with waves as high as 15 metres. While the waves killed four people directly in Tonga, the eruption and consequent tsunami smashed into residential and non-residential buildings alike, damaged other infrastructure such as submarine cables, and contaminated water supplies with ashfall.
Tonga
is one of the most disaster-prone countries in the world.
85,000 people
in Tonga affected by the 2022 volcano eruption.
The event also highlighted how Tonga must quickly build more resilience into its infrastructure and economy if it wants to improve the quality of life for its roughly 100,000 population.
The country is a lower-middle income nation, constrained by its geographic isolation, small market size, and high cost of basic services. A Pacific archipelago of 172 islands, whose nearest neighbours – Fiji and Samoa – are more than 700 kilometres away, Tonga is highly dependent on climate sensitive-sectors such as agriculture, fisheries, and tourism. Its economy is sensitive to external shocks.
Cyclones, tsunamis, and volcanoes cause serious damage every time they hit Tonga, and yet – in recent years – the Pacific nation has experienced more extreme weather events than usual. Cyclone Gita, a category 4 tropical cyclone which hit Tonga in February 2018, was one of the most powerful storms to hit Tonga in decades, killing two, destroying at least 171 homes, and damaging more than 1,100 others.
This immense vulnerability to multiple natural hazards – and the dangers of cascading impacts – led Tonga to become one of four countries – together with Bhutan, Chile, and Madagascar – pioneering the Global Methodology for Infrastructure Resilience Review. Developed by the UN Office for Disaster Risk Reduction (UNDRR) and the Coalition for Disaster Resilient Infrastructure (CDRI), the methodology helps countries to identify and prioritise the strategies that will build their infrastructure resilience through a five-step approach.
1
Stakeholder mapping
- Key ministries, regulators and operators in infrastructure development
- Cross-sector coordination mechanisms
Review of existing policies and regulations
- Policies and regulations shaping infrastructure resilience
- Integration of disaster risks in national plans and strategies
Identification of vulnerabilities (Stress Testing)
- Data collection on hazards and vulnerabilities
- Multi-hazard resilience testing of infrastructure systems
Principles for resilient infrastructure
- Infrastructure resilience assessment using the UNDRR Resilience Principles
- Identification of resilience-building interventions
Development of an Implementation plan
- Results validation and prioritization
- Implementation plan with assigned responsibilities
“The infrastructure resilience review process is already helping us to do that,” he said.
Advancing Infrastructure Resilience in Tonga
- The process
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The process
In 2021, Tonga enacted the Disaster Risk Management (DRM) 2021 Act, replacing the Emergency Management Act 2007, signaling a new ambition to manage risk instead of reacting to disaster.
After the 2022 volcano eruption, it also connected quickly with international partners. With World Bank support, it upgraded its ports, roads, and an airport, making them more resilient to storm surges, floods, and high winds. The Asian Development Bank has also helped with grants to help the country recover from disasters and health emergencies, including the COVID-19 pandemic.
The infrastructure resilience assessment approach in the Global Methodology, provided Tonga with the opportunity to take a holistic look at their infrastructure and risk, identify the gaps, and then fill them.
Stress-testing of Critical Infrastructure against Identified Hazard, Tonga
In the first phase, a technical working group was set up with representatives from 21 departments and agencies across six ministries. Supported by this working group, the review process began with a kick-off meeting that included key stakeholders for infrastructure development, disaster risk reduction, and sectoral operations. Next, in phase two, it reviewed existing policies and regulations, assessing the extent to which they address disaster risks and support infrastructure resilience.
In the third phase, stakeholders conducted stress tests and gap analysis on ten critical infrastructure functions against a range of hazards, including cyclones, droughts, underground water / seawater intrusion, tsunamis, volcanic eruptions, non-communicable diseases, land degradation and erosion, floods, sea level rises, and cybersecurity breaches. By identifying these vulnerabilities, interdependences, and cascading risks, the participants were able to seriously consider the economic impacts and interdependences of different hazards throughout.
Fourth, Tonga’s current resilient infrastructure practices were assessed against the UNDRR Principles for Resilient Infrastructure. These six principles set out the key conditions for sustainable infrastructure resilience. They support the Sendai Framework for Disaster Risk Reduction and Sustainable Development Goals, as well as the G20 Principles for Investing in Quality Infrastructure.
Finally, stakeholders drafted an implementation plan, consolidating the findings and providing a road map for enhancing infrastructure resilience.
“By prioritising resilience, the country can support sustainable economic growth, adapt to climate change, and protect communities, while minimising economic and human losses.”
- Water sector
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Water sector
One of the sectors examined was the water sector, including a deep dive analysis. Water is everywhere in a small island development state (SIDS) like Tonga, of course, but securing a stable supply remains difficult. Water in Tonga comes from ground water and rainwater, which are both vulnerable to impacts from climate change.
Rising sea-levels mean that many assets are at risk of flooding, while soil erosion is also a threat. When sea levels rise, salt water can enter some freshwater supplies, reducing the available water for drinking.
Funding the necessary upgrades, however, is a challenge. The Tonga Water Board (TWB) operates without subsidies, making capital investment difficult.
Meanwhile, the lack of a centralised infrastructure database complicates the assessment and management of existing resources. Multiple institutions manage water resources across the archipelago’s 45 or so inhabited islands, doing so with varying levels of expertise. While integrated planning and coordination should be essential for efficiency, the system is fragmented. Integrated planning and management are urgently needed to ensure resilience in the water sector. Equally as importantly, there’s a need for more data and information, and for a better understanding of how to use the already available data, which does not capture all boreholes and rainwater harvesting.
Challenges are even greater on the outer islands. Most villages lack a formalised tariff system, complicating the collection of revenue for repairs and maintenance. Composed of local residents, Village Water Committees (VWCs) play a crucial role, but they often lack financial and other supporting skills. Without structured regulations and trained personnel, infrastructure upkeep is inconsistent.
“But at the same time, it takes four or five hours by boat to reach some of these communities,” he said. “It is not an easy job.” The support system for water infrastructure needs to be planned, designed, and monitored more effectively to become more resilient to hazards, which is an area of need for VWC.
Finally, the water pumping stations are dependent on electricity. This means that if a cyclone damages the power lines and impacts electricity supply, then water supply would also be affected. The disaster responses are complicated by limited standard operating procedures (SOPs) as cyclones, volcanoes, and tsunamis all affect the water infrastructure in different ways. Take a look at how some of the most recent events have affected Tonga’s water infrastructure:
Hazard-related disruptions in Tonga’s water sector
TROPICAL CYCLONES:
Cyclone Gita (2018) damaged water distribution systems and rainwater tanks, while other cyclones have led to extensive system failures.
VOLCANIC ERUPTIONS AND ASHFALL:
The 2022 eruption of Hunga Tonga-Hunga Ha’apai severely impacted water punps and contaminated rainwater tanks, leading to supply disruptions.
DROUGHTS:
Prolonged droughts in 2023 have affected rainwater collection systems, exacerbating water shortages.
TSUNAMIS:
The 2022 tsunami contamined groundwater sources in southern islands and destroyed coastal water infrastructure.
Several resilience measures do exist. Desalination units provide emergency water, even if their maintenance or repairs sometimes fall on untrained community members, causing delays and potential safety issues. Overall, however, these are uneven and insufficient.
Some development support has been provided, but the projects are also unevenly distributed. They tend to focus mostly on the main island, leaving outer islands underserved.
From the Infrastructure Resilience Review, several recommendations emerged:
- Build Village Water Committee capacity by developing management manuals, training, and emergency water plans for climate and disaster events.
- Establish standard procedures for Village Water Committees to capture and share water data, linking it into a centralised system. Procure and distribute the necessary hardware, then train the VWCs in its use.
- Set up processes to coordinate donor projects across the water sector.
- Review the complete water sector for exposure to hazards, including its dependencies on other sectors such as transport, ICT and energy.
- Find ways to improve the management of both rainwater and groundwater.
- Improve water security on the outer islands by increasing water storage volumes, testing new solutions such as hydro panels and mobile desalination units.
- Transport
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Transport
The Infrastructure Resilience Review also looked at transport, given the importance and vulnerabilities of Tonga’s ports, airports, and roads.
On the one hand, Tonga’s geographic isolation makes it highly dependent on its ports and airports for imports of food, fuel, and spare parts. In 2000, the last available energy balance showed that 75 percent of the country’s energy depends on imported petroleum products. Over 98 percent of Tonga’s grid-supplied electricity is generated using imported diesel.
On the other hand, those ports and airports are highly vulnerable to disruption of the other critical infrastructure functions, including transport. The ports and airports both depend on Tonga’s roads, for example, to connect them with the rest of the country.
Multi Hazards Disaster Risk Assessment, ARUP 2021
However, while Tonga’s climate is already tropical, climate change is expected to bring heavier and more frequent rainfall, damaging roads in the low-lying areas. Inadequate drainage will compound this damage, disrupting transport and mobility to the ports and airports.
In turn, this could also disrupt Tonga’s electricity, which relies heavily on diesel imports, as well as the delivery of clean water to remote areas or even – in case of emergencies – access to evacuation centres.
The Roadmap for Infrastructure Resilience has multiple recommendations for improving road transport resilience, including the following:
- Improve data on infrastructure quality to understand better which rural and urban roads are exposed to flooding.
- Produce geohazard maps to enable monitoring of infrastructure resilience and vulnerability.
- Develop mitigation measures based on assessments of the road quality.
- Integrate climate safety factors into road design.
Additionally, the Roadmap for Infrastructure Resilience in the Kingdom of Tonga makes specific priority recommendations for individual sectors, including the development of a national resilient critical infrastructure strategy, the establishment of a critical infrastructure working group, and the establishment of a central disaster data centre.
“The infrastructure resilience review reminds us that we are not passive actors, but that to a much greater extent we are masters of our own destiny,” said Sione Pulotu ‘Akau’ola, CEO for Ministry of MEIDECC.
“In the long run, building resilience into our infrastructure will save us lives, destruction, and economic damage,” he said.
Download the full report:
Roadmap for Infrastructure Resilience in the Kingdom of Tonga