Cook Islands coastal calculator sums up climate change adaptation with new harbour

After close to a decade of being without a harbour, the island of Mangaia in the Cook Islands cut the ribbon to a new climate resilient harbour this year, an outcome of the Pacific Adaptation to Climate Change Project (PACC).

In 2005 Cyclones Meena and Nancy destroyed the harbour, making life harder for the islands residents. If there were rough conditions for the island, ships would not berth at the harbour and depart without bringing goods ashore, goods that ranged from building supplies, food supplies and fuel.

Since the newly renovated harbour was launched, no ships have had to turn back. But of course, the real test is the next cyclone or any unusual and extreme tidal surge.

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Above: The opening of the harbour.

"Before this new harbour, we had to rely on calm weather if ships were to come in and, on average, you would get a ship every second or third month; the alternative was to air freight goods in, which was costly," said Mr. Paul Maoate, an engineer with Infrastructure Cook Islands.

What is unique about this harbour is it was built to be climate resilient. To help this happen, a Cook Islands Coastal Calculator was developed, which took into account a range of different scenarios to help guide the design of the harbour renovation so it would be as climate resilient as possible.

Developing the Cook Islands Coastal Calculator took several months in the making as a wide range of information had to be programmed into the formula such as key measurements in distance of beach to the reef, the slope of the reef, the main features on the beach, the intensity and frequency of storms, the contour of the reefs as well as results of a bathymetry study.

Over the course of two years all necessary information was collated and input into a formula to generate the calculations.

"Based on this, the harbour in Mangaia is prepared to withstand the possible extreme conditions that could impact it, however in 50 years time or so we will need to revisit it and upgrade, but we have this in place for now making it as resilient and safe as possible," said Maoate.

"One of the best things about this coastal calculator is that its' database includes all the islands of the Cook Islands, from Mangaia in the south to Penrhyn in the north. This means that we can easily use this calculator for the building of other coastal infrastructure in any of our 15 islands. We've already used it to design a new wharf for the island of Manihiki."

The wharf design has also worked with the natural surroundings, choosing to use the raised tidal reef flats and cliff edges surrounding the harbour to break waves and absorb the wave energy instead of building sea walls.
"This design is so much safer, we've not only worked with what we already have in terms of the tidal reef environments, we have also amended the design so the wave action doesn't cause whirlpools within the harbor itself. This was the case when renovations first began in Mangaia," said Maoate.

"After the 2005 cyclones there was an initial attempt to renovate the harbour but we had to redesign that as there was so much that needed to be fixed."

Safety in this new design is evident in the wave action that no longer creates whirlpools during rough weather, fishermen now have an area where waters are calmer so they can berth in times of rough seas and children and families are now able to use this area as a swimming and picnic area.

"We see so many benefits from this, now it is easier to get cargo and can help drive economic stimulation. It can also act as a place for the community to come together for recreational activities and one of the very first things we noticed was a lot more fishermen went out. This new harbour has made a difference in Mangaia."

The PACC Project in the Cook Islands will be showcased during the Third International Conference on Small Island Developing States in Apia this month. A special side event launching the 'Vital Harbour', a short film on the project, followed by a panel discussion will be held on Wednesday 3 September from 11 – 12.30pm in the Manono Media Centre Conference Room 1 at the UNSIDS venue. Those attending the UNSIDS conference are invited to attend.

The Pacific Adaptation to Climate Change (PACC) Project began in 2009 and ends in December this year. PACC covers 14 Pacific island countries, including the Cook Islands, helping to adapt to climate change by targeting one of the three key areas of food security and production, water resource management and coastal protection.

PACC is a multi-million dollar activity funded by the Global Environment Facility and the Government of Australia. The United Nations Development Programme (UNDP) is the implementing agency and the Secretariat of the Pacific Regional Environment Programme (SPREP) is the implementing partner, responsible for coordination and overall project management.
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