The State Government is considering an $80 million plan to increase the capacity of Lake Argyle by 10 times the volume of Sydney Harbour.
The extra water would be used to attract billions of dollars in investment to develop 100,000ha of agricultural land in the east Kimberley and Northern Territory as part of the Ord River Irrigation Scheme.
Water levels in Lake Argyle would rise 4m under the plans, which are well advanced after positive findings from government commissioned pre-feasibility study which included input from consulting engineers GHD.
Capacity would rise from 10,670 gigalitres to 15,500gl — Sydney Harbour has a volume of about 500gl — by building a barrier wall across one of four spillways leading off Lake Argyle.
The wall would be built 4m higher and downstream from the existing 6m-high barrier across Spillway Creek, which many sightseers cross when visiting Lake Argyle from Kununurra.
Under the plan, the old barrier would be submerged and the road and bridge raised.
Ord East Kimberley Expansion Project director Peter Stubbs said work should start within the next few years to prevent private investment stalling and Australia missing out on a golden chance to develop the north.
“I wouldn’t say it is a long-term plan, it is relatively short,” he said.
“If development is going to go ahead into the NT, at Cockatoo Sands and other sites, we are going to need more water.”
Shire of Wyndham East Kimberley president John Moulden last week told The Kimberley Echo he hoped Prime Minister Kevin Rudd’s flying visit to Lake Argyle would include an announcement about the plan to increase the lake’s capacity.
“I had hoped for an announcement on that today, but maybe there is more to come ... because it is certainly one of the things that will need to be addressed before we get full production out of this system,” he said.
Cr Moulden said he felt the $10 million pledge made by Mr Rudd to start native title discussions between traditional owners and the NT Government fell short of his expectations.
The plan to raise the spillway recognises that although Lake Argyle has massive reserves, water levels must stay high to keep turbines at the hydroelectricity plant operating efficiently so environmental flows into the Ord River are not reduced.
There is about 15,000ha of agricultural land on the irrigation scheme and a Chinese-backed company is developing another 15,000ha under a lease agreement with the State Government.
Other sites earmarked for development include 6000ha known as Cockatoo Sands and 30,000ha at Bonaparte Plains, formerly Ning Bing.
The WA, NT and Federal governments have signed a memorandum of understanding on extending the irrigation scheme into the NT, where Chinese developer Kimberley Agricultural Investments has made no secret of its desire to access more land.
The irrigation channel stops just 6km from the border, but the NT Government must resolve native title issues with the traditional owners before it can be extended.
WA Agriculture Minister Ken Baston met the NT’s project leader Lorraine Corrowa and Miriuwung Gajerrong Corporation leaders in Kununurra this week to discuss progress.
Mr Baston urged the Federal Government to provide seed capital to advance the project on the NT side of the border.
He said the State Government would fund detailed assessment work on the Bonaparte Plains site under the $297.5 million Seizing the Opportunity budget initiative.
Mr Stubbs said it was important for the NT Government and the Miriuwung Gajerrong Corporation to have an in principle deal on development in place by next year, and to have land in the marketplace by 2015 to give investors confidence.
KAI needs land in the NT to achieve the scale required to make its plans to build a high-tech sugar mill feasible.
It is expected to meet the bulk of the cost of extending the irrigation scheme as part of overall investment which could top $1.5 billion.