Cooks Chamber Of Commerce Wants Lagoon Algae Removed

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Pacific Islands Development Program, East-West Center With Support From Center for Pacific Islands Studies, University of Hawai‘i

Excavator scraping pushed to remove overgrowth

By Florence Syme-Buchanan

RAROTONGA, Cook Islands (Cook Islands News, Feb. 3, 2016) – The Chamber of Commerce is lobbying for approval from the Rarotonga Environmental Authority to use an excavator to remove some of the algae that’s smothering Muri lagoon floor.

The plan that’s backed by the village aronga mana (traditional chiefs) and Ngatangiia’s member of Parliament will involve clearing half a hectare near the shore.

Chamber president Steve Lyon says this represents less than 5 per cent of the overall lagoon area.

Lyon has a degree in Environmental and Marine Science,and has developed the proposal to test using an excavator to remove the layer of algae from a controlled section of the lagoon.

"This algae is well established, and a trial the Muri community took part in last year showed that removal by hand was not feasible. Therefore we have looked at several other methods and after consideration decided that using an excavator may be the most effective and least impacting method " says Lyon.

"While the lagoon is not a health risk, it does pose an ecological and aesthetic problem that needs to be resolved".

The Chamber president has met with deputy prime minister Teariki Heather and Environment minister Kiriau Turepu to inform them of the proposal and seek approvals.

According to Lyon, the National Environment Service is accepting the proposal is a trial, and has discussed it at a meeting of the Rarotonga Environment Authority.

"We are now awaiting approval from them to go ahead with the trial so we can use that information to develop a proposal and write an EIA to complete a more extensive clearing of the algae."

Once the trial is complete any further work will require an EIA and the public will be able to make submissions on the project.

Lyon says this is not the only proposed solution. Others have suggested the laying of salt on the algae to act as a desiccant, the towing of a dredge to scrape up the algae and using high pressure to blast algae off the lagoon floor.

Lyon understands there will be some objection to the method he’s proposing and says ‘after careful consideration of the risks, leaving the algae in place is just making the situation worse’.

"The lagoon floor needs the chance to rehabilitate, and it will not clear the algae by itself. By clearing the algae the white sand has been shown to re-establish and the lagoon will recover".

He says keeping the area clear will require some ongoing management but research done since last year shows this is possible.

"This is the first stage of the longer term strategy put forward by the Chamber" says Lyon.

He emphasised that work needs to start on establishing waste water reticulation for Muri as the long term solution. Similar problems in other places such as French Polynesia were completely resolved once reticulated waste water systems were introduced.

Tairi te Rangi Tupe Short agrees saying the focus now needs to be on a reticulation system that will fix the problem at the source, and government needs to move quickly on this.

He says digging channels, dredging, scraping, and removing fish-traps are all short term actions that will not solve the problem of nutrients leaching into Muri lagoon.

It’s estimated if government were to commence on a Muri reticulation project now, it would take a minimum of 18 months to get finance and organise installation.

On November 26, 2015, cabinet declared the state of Muri lagoon a national disaster with DPM Heather leading the charge to ‘act now’. He instructed Public Health to place all commercial properties in Muri on notice that their sewerage systems must be compliant by April 16 this year or their businesses would be shut down.

This is the second formal warning given to commercial properties on the Muri foreshore. In April 2014 all were told they would have two years to install waste water systems that met all the criteria.

It’s been disclosed that a staggering number of commercial properties have not made any effort to get upgraded since April 2014.

Over 90% of Muri businesses situated on the foreshore have sewerage systems that don’t meet the required standard and are non-compliant.

Heather gave the assurance in November last year that none would be given an extension after April 16, 2016, as all have had ample time to arrange installation of approved sewerage systems suitable for foreshore commercial properties.

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