Buffer dam guarantees irrigation water flow for scheme

The Northern Midlands Irrigation Scheme has reached an important construction milestone with a new drop structure successfully installed within the tailrace at the Poatina Power Station.

The drop structure will enable water diversion into the Poatina buffer dam during periods of high water flow.

This enables the scheme’s flow rate to be delivered even when the Poatina Power Station is not operating at full capacity, ensuring irrigators receive the water they need.

Tasmanian Irrigation CEO Mike Sylvester said cooperation and support from Hydro Tasmania has been invaluable.

“The successful completion of works is an example of outstanding collaboration between Tasmanian Irrigation and Hydro Tasmania, which facilitated a 16-day planned shutdown of the Poatina Power Station aligned to our project critical path,” Mr Sylvester said.

“The partnership approach was instrumental in maintaining project momentum and avoiding potentially significant scheduling delays.

Hydro’s willingness to coordinate the power station shutdown allowed us to complete this complex installation work safely and efficiently.

“Completing the works in the shortest time possible, to keep the power station outage to a minimum, also relied on input from head contractor Hazell Bros.

Hazell Bros substituted a pre-cast solution for manufacture of the drop structure instead of cast-in-situ concrete.

Twin 400 tonne cranes were used to lift the pre-cast concrete panels into place.

The project remains on track with completion of the Poatina buffer dam expected in October, and first water to be delivered from the scheme in time for the summer 2026/27 irrigation season.

“This scheme will deliver reliable water where and when it’s needed, giving farmers the confidence to invest now in their farm businesses,” Mr Sylvester said.

“Irrigation is transforming Tasmanian agriculture, creating economic value and expanding farm production to meet the growing demand for Tasmania’s premium produce.

“The Northern Midlands Irrigation Scheme will deliver 25,500 megalitres of water across 7000 hectares of farmland.

The $217.9 million scheme is jointly funded by the Australian Government through the National Water Grid Fund ($108.98 million), the Tasmanian Government ($72.26 million), and Tasmanian irrigators through the purchase of water entitlements ($36.72 million).