Welcome to the Minderoo Weirs Project website. The team for the Minderoo Weirs Project (the “Project”) has developed this website to provide information on the Project’s purpose and the benefits it will bring.
MINDEROO
WEIRS PROJECT
The Minderoo Weirs Project involves the construction of 10 weirs, visible as 40m long low-lying accumulations of natural rock at points along the 600 km long Ashburton River.
The 10 weirs slow the flow of a small amount of water at the end of the river flow, meaning that water on the surface stays there for longer, increasing the amount of water reaching groundwater stores, called aquifers.
By increasing the amount of water stored naturally in the aquifer, fresh water that was previously released to the ocean can be used for purposes that care for and improve the Ashburton River and the land surrounding it, which can deliver environmental benefits.
LEAKY WEIRs
WHAT are leaky weirs?
Leaky weirs are a simple way to increase the amount of water that is stored underground. The weirs are not dams, they do not stop the flow of water.
They work by slowing the flow of water, meaning that water on the surface stays there for longer. This extra time means water has more chance of seeping into the earth, increasing the amount of water reaching groundwater stores, called aquifers.
Leaky weirs are used in types of Managed Aquifer Recharge (MAR) schemes. MAR schemes use different methods to get water into natural underground aquifers where it can be stored.
the river bed
Where do leaky weirs get built?
The Ashburton River has natural high points, called riffles. These riffles, or high points in the riverbed, already help create pools towards the end of a river flow. Leaky weirs are positioned to enhance these naturally occurring riffles.
HOW do leaky weirs get built?
The weirs will be built when the Ashburton River is dry which means the construction works will not block the river flow.
During construction there will be some ground disturbance on the surrounding land, to enable access of machinery and materials to site. Plans will be put in place to ensure the nearby trees and plants are protected.
PROJECT TIMELINE
Section 18 notice given
for 10 weirs
Application made to review the Minister’s decision to refuse the Section 18 consent in State Administrative Tribunal
Appeal allowed, with the matter to be sent back to the State Administrative Tribunal for a fresh hearing
Hearing provisionally listed in the State Administrative Tribunal
Minister refused the Section 18 consent
State Administrative Tribunal affirmed the Minister's 2019 decision to refuse the Section 18 consent. That decision was appealed to the Court of Appeal of the Supreme Court of Western Australia.
Mediation between FFPL, BTAC and the Minister to occur
Other developments
in the river
—
Telegraph weir
Existing leaky weir constructed in 2010 with
support of Thalanyji.
—
Nanutarra Bridge
Bridge crossing the Ashburton River.
—
MINDEROO BRIDGE
Steel and concrete bridge including columns in the riverbed.
—
SCOTTY's WALL
Weir known as Scotty’s Wall, built in 1959, to prevent sea water migrating upstream.
—
GAS PIPELINES
Five gas pipelines in the Ashburton River, requiring the excavation of the riverbed and banks.
—
Sand And
Shingle Mining
Since 2010, river sand, shingle and rock has been excavated and quarried from the riverbed and banks at numerous sites along the river.
HOW WILL THE WATER BE USED?
The Minderoo Weirs
Project will make more groundwater available.
Of the water that is pumped out and used, most of it will be used for agricultural and environmental purposes.
The primary objective for using the additional water is to deliver environmental benefits by enabling activities that will improve and protect the natural ecosystems in the area and broader region, through the improvement of the land and soils to improve biodiversity, agriculture productivity and store additional carbon in soils.
A smaller proportion of the available water may also be used for industrial water and for the Town of Onslow. This is because water supplies in the Pilbara are limited, which can create a barrier to development and concern in local communities.
FAQs
Will the Minderoo Weirs Project dry out the river?
No, the River will still run as usual and only a very small amount of water is slowed down at the end of the flow when it is held up at the weir, and slowly seeps into the ground and around the weir on the way to the Ocean.
Can FFPL pump out all the water from the aquifer?
No. FFPL does not intend to pump all the water from the aquifer. The pumping of water from the aquifer will also be regulated by the water licence issued by the Department of Water.
Why does FFPL want to do this project?
FFPL wants to construct the weirs to make more water available. Of the water that is naturally stored, pumped out and used, the majority of it will be used for agricultural and environmental purposes.
A smaller proportion of the available water may also be used for industrial water and for the Town of Onslow. This is because water supplies in the Pilbara are limited, which can create a barrier to development and concern in local communities.
How do we know these weirs will work?
A leaky weir (Telegraph Weir) was constructed in the Ashburton River in 2010, and since then it has been working to slow down the end of the river flow, to give the water time to seep into the ground and into the aquifer.