Maritime·Cook Islands Ports Authority (CIPA)·—·Cook Islands Ports Authority (CIPA)

Avatiu Port Cook Islands Climate-Proofed Wharf

50-year design life · wharf raised 0.5m with 0.5m further adaptive capacity · rock armour extended 92m

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Key insight

Building in adaptive capacity (the ability to raise the wharf a further 0.5m) at design stage costs marginally more but eliminates the need for a full rebuild as sea levels rise — a key design principle for long-lived coastal infrastructure.

Transferability to UK: MediumAdaptive port design principles (designing for incremental height increases as sea levels rise, flexible fendering systems) are directly applicable to UK coasta

Avatiu Port on Rarotonga, Cook Islands — handling 90% of the island's food imports — was rebuilt with a 50-year climate-resilient design: wharf deck raised 0.5m with capacity for a further 0.5m uplift as sea levels rise, rock armour breakwater extended 92m, and fendering systems designed for height adjustment. Avoided an estimated NZ$20m in emergency repair costs.

Climate drivers

Sea level riseStorms and high winds

Impacts

→Coastal erosion→Storm surge→Port structural failure

Adaptation measures

  • Wharf height increase
  • Rock armour breakwater extension
  • Raised mooring bollards
  • Adaptive fendering system
  • Harbour dredging

Assets affected

Port structuresPort servicesBreakwater

Investment

US $24.6m (£16.1m); 84% ADB financed

Band: £10m–£100m

Delivery period

—

  • The Cook Islands are highly vulnerable to tropical cyclones, which bring storm surges and high winds that seriously deteriorate the structural integrity of coastal infrastructure .
  • Sea levels are also rising, having risen 14cm on Rarotonga, the Cook Islands’ most populated island, from 1993 to 2024, which has significantly increased the island’s risk of coastal flooding . By the end of the century, the Cook Islands are likely to experience over 100 days of flooding annually .
  • Avatui Port, a 260m long facility, handles 90% of Rarotonga’s food imports and all its fuel supply . More severe and frequent climatic events had been increasing the likelihood of catastrophic damage to the port, which would have left the island population’s supply of food at risk .
  • To adapt to these increasing hazards, the wharf has been reinforced with updated infrastructure that is more resilient to waves and erosion, and designed with the capacity to be raised as sea- levels continue to rise.

Ref: ID_09 · Cook Islands Ports Authority (CIPA) · Curated & verified by HIVE

Transferability to UK: Medium

Adaptive port design principles (designing for incremental height increases as sea levels rise, flexible fendering systems) are directly applicable to UK coastal ports and harbour infrastructure.

UK contexts

UK island and remote community portsCoastal port infrastructure facing sea level riseAssociated British Ports managed facilities

Applicable to UK coastal

Transfer to other sectors (AI)