Australia's oil and gas industry may need to care for Aboriginal heritage offshore in the same way as when working onshore and Woodside's operations around the World Heritage listing-nominated Burrup Peninsula are especially sensitive.
Scientists working in partnership with the local Murujuga Aboriginal Corporation have found ancient Aboriginal artefacts in the waters of the Dampier Archipelago that were once dry land.
Murujuga is the traditional Aboriginal name for the Dampier Archipelago and surrounds and includes the Burrup Peninsula: home to Woodside's North West Shelf and Pluto LNG plants.
The Australian and WA governments are preparing to nominate Murujuga for World Heritage listing due to the more than one million petroglyphs, or ancient rock art, found onshore.
The Deep History of Sea Country research project found 269 artefacts in shallow water off Cape Bruguieres that radiocarbon dating indicated were at least 7000 years old. An ancient freshwater spring that is now underwater in Flying Foam passage yielded more finds.
Flinders University scientist Chelsea Wiseman said dry land once extended 160km from the current Pilbara coast and Aboriginal people would have lived there for generations.
"Our discovery demonstrates that underwater archaeological material has survived sea-level rise, and although these sites are located in relatively shallow water, there will likely be more in deeper water offshore," Wiseman said.
"Australia is a massive continent, but few people realise that more than 30 per cent of its landmass was drowned by sea-level rise after the last ice age,
"This means that a huge amount of the archaeological evidence documenting the lives of Aboriginal people is now underwater,
"The ancient coastal archaeology is not lost for good; we just haven't found it yet."
Murujuga Aboriginal Corporation chief executive Peter Jeffries said the discoveries added to the story of Aboriginal people in the Pilbara.
"Further exploration could unearth similar cultural relics and help us better understand the life of the people who were so connected to these areas of land which are now underwater," Jeffries said.
"With this comes a new requirement for the careful management of Aboriginal sea country as it's not automatically protected by current heritage legislation."
Flinders University associate professor Jonathan Benjamin said artefacts found in the sea are often relatively well preserved compared to finds on land. Many of the stone tools found off the Pilbara coast had sharp edges that indicated the sea had not moved them a great distance.
Make archaeology part of the project
Benjamin said it was standard practise in Europe to consider submerged ancient history. He worked on a study of an area in the English Channel dredged for aggregate where archaeologists found Neanderthal stone tools in the dredged material.
"Why wouldn't we consider ancient archaeology around this continent as well in our planning and consent phase, especially now that we've demonstrated beyond a shadow of a doubt that it does exist?" Benjamin said.
"I'm not anti-industry, I don't want to stop any progress and development, but I want to work with industry...just as I want to work with traditional owners that have potentially a spiritual connection to this stuff,
"We're not just purely here to make money and extract the resources, but I understand that's the economy we live in."
Benjamin said any offshore development should have a heritage management plan that considered ancient artefacts as well as more recent shipwrecks, that legislation does protect.
He said it would be best if geologists, geomorphologists and archaeologists worked together from the early stages of a project. High-resolution marine geophysics and analysis of geotechnical cores would help locate areas where artefacts could have survived.
"The sooner all industry around Australia engages with this the less of a problem it will be for them," Benjamin said.
Scarborough pipeline approval under appeal
The two finds are to the east of the route of a pipeline Woodside plans to build to take gas from its Scarborough field to the Pluto LNG plant.
Benjamin said the WA Environmental Protection Authority and Woodside were told about the finds last year.
The Murujuga Aboriginal Corporation said in a submission to the EPA dated September 2019 and obtained by Boiling Cold that it understood the pipeline proposal included "both direct (removal of submerged rock are during dredging) and indirect impacts."
A Woodside spokesperson said no rock art, or petroglyphs, would be damaged within Woodside's areas of operation.
"Woodside welcomes the Deep History of Sea Country Project study, which took place outside these areas, and which indicates the potential for artefacts rather than rock art," the spokesperson said.
"The proposed Scarborough dredging will not impact any igneous (volcanic) rock, which is the type of rock on which Murujuga rock art has been found."
Woodside acknowledged a potential for submerged heritage and conducted extensive onshore and nearshore archaeology and ethnographic cultural heritage and geotechnical surveys, the spokesperson said.
"These surveys have not identified submerged heritage materials,"
"These surveys identified one nearshore archaeological site within the Pluto LNG foundation lease area which remains intact and protected."
In January, the EPA recommended to Environment Minister Stephen Dawson that he give environmental approval to the nearshore part of the pipeline route in State jurisdiction.
The Appeals Convenor Emma Gaunt is investigating two appeals against the EPA's recommendation.
Gaunt said the matter was a priority for her office and her recommendation would be sent to Minister Dawson, who makes a decision that includes economic and social issues as well the environment.
A presentation Woodside made in Karratha recently stated the company expected a decision mid-year.
Woodside is currently reviewing the Deep History of Sea Country research, a company spokesperson said, and would engage with the MAC and the researchers to understand the new findings.
"Woodside will continue to work with key stakeholders to protect heritage and minimise any impacts both onshore and offshore, including for the proposed Scarborough and Pluto Train 2 development activities," the spokesperson said.
The Woodside spokesperson said the Murujuga Aboriginal Corporation had provided feedback about its cultural heritage management and dredging plans and made a submission to the EPA. The company was consulting with MAC about the issues it raised.
In the September 2019 submission to the EPA MAC called for the regulator to direct Woodside to identify potential submerged Aboriginal heritage sites in the pipeline project area and develop plans to protect them.
Benjamin said Woodside might have underestimated the potential impact of submerged archaeology.
"I expect they are not underestimating it now after this discovery has been made," he said.
Main image: Archeological dive in the Dampier Archipelago. Source: Flinders University