Results from the investigations provide information on how agricultural activities, on-site septic systems and other activities impact the Muri lagoon as part of the Mei Te Vai Ki Te Vai project.
The Mei Te Vai Ki Te Vai project was launched by the Cook Islands government in early 2017 to improve the water quality of the lagoons in Rarotonga and Aitutaki.
The project not only involves confirming the source of the issues but also identifying what can be done in the short term and providing a road map for investment.
The project also involves developing a concept design for a long-term wastewater management solution, establishment of a Crown-owned water and wastewater authority and engaging with the community throughout and beyond.
To confirm the source of the issues affecting Muri lagoon – research scientist Doctor Douglas Tait of Southern Cross University along with students Michael Reading and Kylie Maguire are testing the water quality of Muri lagoon as well as the ground water flow to the lagoon.
Doctor Douglas Tait is no stranger to the lagoon as his thesis was based on the Muri area and through his work with the WATSAN unit on the island.
Around five research papers based on the Muri area have been published in scientific journals over the years which have informed the conceptual understanding of the Mei Te Vai Ki Te Vai project management unit.
Doctor Douglas Tait says the current testing his team is conducting is focused on investigating where nutrients enters the lagoon, how much enters the lagoon and how long it stays in the lagoon environment.
They are also investigating ground water flow and how sediments in the lagoon may contribute to algae growth.
Also conducting investigations to find the source of the Muri lagoon issues is principal coastal engineer Matt Blacka and his colleague and drone pilot Chris Drummond from the University of New South Wales.
The pair is investigating the lagoon hydrodynamics using equipment anchored to the lagoon floor to gather information on the currents, wave and flushing of Muri lagoon.
They will also map the slope and depth of the lagoon.
They have also been using a drone to map the area with data gathered to be used to create a 3D model of the Muri lagoon and coastal area.
In particular they will be looking to see how the Muri lagoon and coast has changed and how this has impacted the lagoon.
They have also been conducting coastal hazard mapping in the areas from Tupapa to Nikao.
Mei Te Vai Ki Te Vai Hydro-geologist and Environmental Scientist Anthony Kirk says that results and data from the series of investigations by visiting experts and those being conducted by the Ministry of Marine Resources and PMU will be combined together to give a clearer picture of the Muri lagoon issues and ultimately the best way forward to improve the precious environment.
The public is advised that some testing equipment will remain in the Muri lagoon area and ask that these not be disturbed as scientists continue to gather vital data to help develop a sustainable solution to the Muri lagoon issues.
He says that while preliminary results and reports from the investigations are expected to be available in September – there may be some early remedial dredging works in the Muri lagoon to improve the flow and flush of the lagoon with the Environment Impact Assessment currently with the National Environment Service and Rarotonga Environment Authority.
To stay informed about the Mei Te Vai Ki Te Vai project – visit the projects website www.vaikitevai.com or contact the PMU on 28851 with any queries or to subscribe to the monthly newsletter which is available in both English and Maori.
- Matariki Wilson