Giant dams could be built in parts of north Queensland and the Northern Territory to turn those areas into major national agricultural food bowls and generate significant economic benefits, a CSIRO report says.
The Federal Government welcomed the report, saying the dams could revolutionise food production and help drought-proof rural areas.
The CSIRO’s “world-leading initiative” mapped three key river systems — the Mitchell River in far north Queensland, Western Australia’s Fitzroy River and the Greater Darwin area in the Northern Territory — to identify the best sites for potential irrigated agricultural development.
The CSIRO report suggested several dams could be built in Queensland and the Northern Territory and said there were good conditions in Western Australia for irrigated agriculture through harvesting aquifers.
The assessment of Western Australia’s Fitzroy River did not undertake any new analysis of any new dam designs, nor was the potential for major dams to mitigate flooding along the river investigated.
CSIRO project leader Chris Chilcott said almost 400,000 hectares across the catchments could be suitable for irrigated agriculture.
“It’s about the possible, so we’re not proposing those dams,” he said.
“What the report does — and what the work for us has done — is it shows what’s possible, how much land, how much water, and where do they come together that would allow developments to happen.
“And then it allows people to make decisions about how they might do that.”
Federal Resources Minister Matthew Canavan said the dams, if built, could significantly increase Australia’s food production.
“Right now we irrigate just over two million hectares in the whole country,” Senator Canavan said.
“In the Murray-Darling Basin it is about 1.5 million hectares, so 400,000 hectares is really a lot to irrigate into farm production.
“It’s only a small part in single digits of percentages of the area of these catchments.
“But in terms of being able to boost our farm production as a nation, boost our food production, [and] if you take the potential of growing Asian economies, it’s a big deal for the country.”
Senator Canavan said the process would take years, if not decades to implement.
“We’ve always said our northern Australian agenda was not something for an electoral cycle, it’s not something for us to deliver in just three years … it was something to set the country up, set the north up for decades,” he said.
Four dams proposed in Queensland
In far north Queensland, the Mitchell River, which flows between Mareeba and Kowanyama in the Gulf of Carpentaria, the construction of four dams at Pinnacles, Rockwood, Nulinga and near Chillagoe would see an extra 140,000 hectares of year-round crop irrigated.
Queensland Natural Resources Minister Anthony Lynham said he had not seen the CSIRO report, but in principal, he supported the development of northern Australia.
“I’d like to see the economics of it. And let’s see if it stacks up,” Mr Lynham said.
“And look, if you’re relying on the Federal Government to support it, you’ll be waiting a long time.”
Senator Canavan said the Pinnacles dam would be the largest one of the four proposed in Queensland and according to the CSIRO would cost $755 million to build.
“Investing in dams is one of the key ways we can make our country more resilient from drought,” Senator Canavan said.
“In the Mitchell River, the consensus view is that there won’t be much change to rainfall patterns due to climate change.”
Senator Canavan said the region’s climate made it ideal for more farming and the proposed $755 million Pinnacles dam project could have massive benefits for helping farmers during drought.
“If we had had the Pinnacles dam there right now, they would be growing sorghum cotton seed and molasses that could be trucked to these drought-affected areas in Queensland to provide relief,” he said.
“In parts of western and central Queensland they’ve been gripped by drought for years — this area in the Mitchell River has not had drought for most of those years.
“So that would be an important cog in our overall agricultural supply chain.”
The report found WA’s Fitzroy catchment has the potential to support 160,000 hectares of a single irrigated dry-season crop in 85 per cent of years, with 55,000 hectares of coastal land suitable for lined aquaculture ponds.
It found there were streams, wetlands and riparian areas which remained of critical importance to Indigenous people, providing both cultural significance and nutritional food.
It also acknowledged Indigenous communities along the Fitzroy catchment retained significant growing rights and interests in land and water resources.
In the Darwin catchments, a combination of major dams, farm-scale, off-stream storage and groundwater were identified as being able to potentially support up to 90,000 hectares of dry-season horticulture and mango trees.
Two potential dams were proposed at Arrows and in the upper Adelaide River to release a possible 436 gigalitres of water across the region.
Federal Infrastructure, Transport and Regional Development Minister Michael McCormack said the findings could be a major coup for the regions.
“$5.3 billion annual economic activity [and] 387,000 hectares of additional crops,” he said.