Design and operation of Torrumbarry Weir

Torrumbarry Weir

Torrumbarry Weir is located between Echuca and Swan Hill on the River Murray.

The State Rivers and Water Supply Commission of Victoria constructed the original Weir and lock for the River Murray Commission. Construction was completed in 1924. The original Weir consisted of a series of steel trestles that were guided along a concrete slab extending the full width of the river. The trestles were placed and removed using a cable driven by a steam-powered winch. The height of the weir pool was adjusted by manually adding or removing horizontal wooden drop boards on the upstream side of the trestle frame. This is the same construction as the existing Mildura Weir.

On 27 May 1992, a significant leak was discovered under the footings of Torrumbarry Weir. Detailed inspection revealed a hole under the weir approximately 20 m wide by 5 m deep. Urgent repairs were made to allow the weir to continue to operate while a range of options was considered for its repair or replacement. The final decision was to replace the existing weir.

Between 1993 and 1996, the new Torrumbarry Weir was designed and constructed. The Prime Minister, the Honourable Mr. John Howard, officially opened the weir on 12 March 1997. The new structure was built for $33 million, being built below budget and within the original timeframe.

Purpose

The purpose of Torrumbarry Weir is to allow the diversion of flows for irrigation, particularly into the Cohuna, Kerang and Swan Hill areas of Victoria. The National Channel carries water from the Torrumbarry weir pool to farms in the adjacent areas.

The National Channel has a capacity of 4 400 megalitres per day. The Torrumbarry Irrigation System delivers an average of 500 000 megalitres per year to approximately of 120 square kilometres.

Farming activities utilising irrigation include dairy farms, fat lambs, beef cattle, stone fruit, grapes and vegetables. The annual gross value of the local agricultural products is about $130 million.

The Catchment

The Torrumbarry Weir and Lock 26 are located 1 638 km from the mouth of the River Murray, and 892 km from the source. It takes approximately 16 days for Murray flood flows originating from rainfall at the eastern end of the Murray-Darling Basin on the Great Dividing Range to reach Torrumbarry Weir.

Torrumbarry Weir is located 74 river kilometres downstream of Echuca, and 133 river kilometres upstream of Swan Hill. The weir pool level at Torrumbarry determines the river level as far upstream as Echuca during the fully regulated mode of operation.

Major tributaries of the River Murray upstream of Torrumbarry Weir include the Kiewa, Ovens, Goulburn and Campaspe rivers.