Journal - ASR Limited: Coastal and Marine Consulting

Monday

Jan022012

Dr. Jose C. Borrero Seminar

Dr. Jose C. Borrero of ASR Limited (New Zealand) describes his recent field work and modeling the formation and source of Garbage Gyres.

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Adam Daigian

Monday, January 2, 2012

Thursday

Oct132011

Oil Spill from Rena, Bay of Plenty, New Zealand

Numerical modelling and Field Survey

The 47,000 tonne container vessel "Rena" ran aground on the Astrolabe Reef, off the North Island of New Zealand on Wednesday 5 of October. As of today, traces of oil have been reported along the Bay of Plenty shore, streching from Mount Manganui to Maketu, and also extensively on Motiti Island. The Rena is located at 37.5416 S, 176.425 W and is firmly aground on the Astrolabe Reef. A week since the incident, an estimated volume of 300,000 litres of fuel has leaked into the sea.

On Thursday 13^th of October, ASR Marine Consulting and Research sent two teams of scientists led by Edward Atkin and Laurent Lebreton to survey the extent of the oil spill in order to validate the numerical model that forecast the oils slicks movements.

The teams surveyed 60 km of coast from Mount Manganui to Matata with 14 transects spaced every 5 km. At each transect, teams took images of the beached oil dispersal, evaluated the relative concentration of oil on the beach and interviewed local residents, asking “when the oil firstly appeared and how much oil has already been cleaned up?” These surveys took place during Thursday’s outgoing tide from 9.00 am to 3.00 pm.

The following map shows the results of the survey overlaid with the numerical model of the oil’s extent, at the time of the survey. The field observations matched the numerical model showing beached oil from Mount Manganui to South of Papamoa Beach; as well as on the rocky point between the Maketu estuary and Waihi Estuary. The highest concentration of oil was found at Papamoa beach with an approximately 1km stretch of beach heavily covered with oil.

The following shows the forecast for the next few days with oil progressively leaving the affected part of the coast. The strong westerly wind should push the oil more offshore and further down the coast during the coming weekend. The forecast extends out to Sunday 16^th. An updated simulation will be made available as further data becomes available.