Since 2007, ROC has dedicated resources to marine habitat rehabilitation at our Cliff Head facilities. The Cliff Head project comprises: an offshore, unmanned oil production platform located in the Commonwealth Waters; an onshore processing plant; and two subsea pipelines that connect the platform and the onshore processing plant. Offshore, the two subsea pipelines run parallel within 5–30 metres of each other and cross extensive seagrass meadows.
Following advice from the Western Australian Environmental Protection Authority, the Western Australian Minister for the Environment established a set of Ministerial conditions for the site. As a result, ROC formulated a Seagrass and Seabed Monitoring Programme, which began in 2007.
During the 2009 survey, 40 seagrass meadows were monitored. A team of three divers was employed to perform survey work to assess:
- the condition of the seabed (signs of sediment build-up or erosion, and scouring); and
- the type, density and cover of macrophytes (seagrass and algal species) along the edge of, and colonising, the impact area.
In addition, other observations were recorded through video footage, photos, mud maps and detailed notes of each site. These records were used in post-survey analysis to provide comparative information regarding changes in appearance and stability of seagrass meadows.
The results showed that the total seagrass loss attributed to the installation of the pipeline to be within the 'best case scenario' and demonstrated a net recovery of seagrass across the project area since 2007. In two years time, ROC intends to conduct a final survey.