Muri Beach erosion remedial works

7 January 2019

After recent heavy downpour Nukupure Beach in Muri was scoured severely again after the same erosion occurred during heavy rainfall in April. Natural drainage channels were overwhelmed during the heavy rainfall and overland flow (moving flood waters) was seen across Muri village. 

“A holistic approach is required for the area, in fact the whole island needs a drainage and stormwater control overhaul and Infrastructure Cook Islands (ICI) are working towards improving this area” says an ICI spokesperson.  The heavy rainfall we have experienced three times this year is highlighting the predictions by climatologists that long term climatic events will be characterised by less frequent but more intense rainfall events.  “We can expect the same rainfall to keep happening in the foreseeable future therefore we have to adapt to this expectation in our development.  We cannot keep filling in wetlands and lowlands, we need to build accommodation higher, harvest rooftop rainwater, and we need to invest in a drainage system but one that works to ensure reduced sedimentation to the marine environment.  Simply clearing stream banks is not a good idea as this does not allow the capturing of sediments before storm water enters the lagoon”.

In remediating Nukupure Beach, three organisations have plans for the area.  Two activities have been planned for already by the Mei Te Vai Project and Muri Environment Care.  The two activities plan for beach replenishment and stabilisation work.  “Due to these plans, ICI has decided it would be best to save money and mined sand and wait for these two plans to be carried out.   The beach erosion is not a safety hazard for anyone, it is just an eyesore at the moment however, remedial work on the rugby field is taking place in order to allow for the sports field to be used safely” says the spokesperson.    

After the most recent erosion at Nukupure, ICI engineers are designing a measure to divert stormwater away from the main rugby field area and with suitable retention measures.  Better measures upstream of the area will need to be made to alleviate the pressure downstream in the long term.

Across the world, it is standard for infrastructure to be built to withstand what is termed ten year rain events not one hundred year events.  In defining the two events, ten year events have a 10% chance of occurring in a given year whereas a one hundred year event has a 1% probability of occurring in a single year.  To build all infrastructure to cater for a one hundred year event is unaffordable and we know that Small Island Developing States such as the Cook Islands can struggle to cater even for ten year events. 

ICI asks for everyone to consider best practices when planning their developments and will be producing a development guide to provide clear directions on development under the ICI Ridge to Reef Project.  Employing best practices will be encouraged through the guide based on where development standards are heading to, to ensure the best outcomes for the community.