Landslide update

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Number: A26/2016

Date: 21 October 2016

Relevant: Christmas Island

Topic: Landslide Update

On Friday 21st October 2016, the Executive of the Christmas Island Emergency Management Committee (EMC) met to discuss the current Level 2 rockfall restrictions in Flying Fish Cove and active voluntary evacuation order for the Kampong. The Level 2 warning was activated in response to the landslides which occurred on the 13th October 2016 following a period of unprecedented rainfall. Six slips were recorded, including one which was estimated to be 2000m³ in volume.

In attendance was the IOTA contracted geotechnical engineer, who has been on island since Tuesday 18th October 2016 conducting an assessment of the residual rockfall hazards and overall stability of the cliff faces.

In considering whether to lift the restrictions, the following factors were discussed:

  • Public safety;
  • Prevailing and anticipated weather conditions;
  • Access to critical infrastructure at Smith Point; and
  • The available lines of defence, namely:
    • 1 rockfall fence panel has been destroyed in the Cove; and
    • The Madrassa has only one fence and no berm to protect from the high risk area behind it.

Upon consideration of these factors, the following decisions were reached and will take effect immediately;

  • That access to Flying Fish Cove be restored to the public up to the Western edge of the boat ramp. This will enable access to launch/recover boats, whilst keeping members of the public outside the area of risk posed by the damaged rockfall fence panel. Users will not have access to boat trailer parking in this area;
  • There is no access to Smith Point, Tai Jin House, or any area past the Western edge of the boat ramp to members of the general public. The longevity of these restrictions will be advised once a timeline for repair or replacement work to the rockfall fence has been established;
  • That access to Smith Point be restored only to critical operational users of the infrastructure in this area, namely the fuelling facility and waste water plant. Access is only to occur with the express permission of the AFP.
  • The voluntary evacuation order has ceased. Precautionary measures for future rainfall events will be implemented noting the increased risk to the Madrassa, playing fields and basketball court. These areas will be closed during heavy rainfall events; and
  • Access to Murray Road (Drumsite) be restored—a formal risk assessment deemed this area safe.

There is considerable work to be done to address the long term rockfall risk mitigation strategy. This work has been referred to the Disaster Recovery Committee (DRC) for action. The DRC will advise a strategy and timeline for clean-up of landslide debris in the restricted area of the cove.

The landslides are evidence of the impact of sustained heavy rainfall. These weather patterns are expected to continue over the coming months, and further rockfall alerts are likely. The restrictive nature of these warnings is designed to protect the community from this risk. The measures have proven to be effective, ensuring no personnel were in the Cove when the landslide broke through to the car park. Community cooperation with the directions of the EMC thus far has been greatly appreciated, and the Committee will continue to work with residents and stakeholders to develop appropriate responses to these emergencies.

Any questions, concerns or feedback on the Executive’s decisions, or the management of the Level 2 alert should be directed to the IOTA Emergency Management Officer, Jessica Sullivan, via operations@infrastructure.gov.au or mobile 0418 766 703.

Barry Haase
Administrator
Indian Ocean Territories