Thomson Bay hydrocarbon site
In August 1997 a fuel leak was detected in the 2-stroke fuel supply bunker located near the fuel jetty in Thomson Bay. It was estimated that approximately 12,000 litres was leaked. This leak was the subject of extensive media coverage at the time.
Following investigation and monitoring, which included a trench dug near the shoreline that confirmed that no free phase product was emerging to contaminate seawater, a diesel leak was also detected in the vicinity of a now removed underground storage tank. Both leaks were found to have entered into the groundwater causing both a dissolved phase hydrocarbon plume and phase separated hydrocarbon (PSH) at the watertable. This water does not form part of the drinking water supply for people or fauna, and does not come into contact with any person.
A strategy of product collection was instigated in 1997 and included the installation of a recovery enhancement trench which removed between 3000 to 6000 litres of fuel. A monitoring program then commenced to detect any further spillages and plume movement. No impact from the plume has been detected in the nearshore marine waters.
The Rottnest Island Authority has maintained the monitoring program and is investigating options to further remediate the affected area.