Dethridge wheel

Lore & Background

John Stewart Dethridge, as Victorian State and Water Supply Commissioner, developed the Dethridge wheel in 1910 to accurately measure water flow at irrigation sites in Australia, particularly in New South Wales and Victoria. The wheel was designed to regulate water use for sustainable irrigation, especially given Australia's vulnerability to drought. It was used continually through the 20th century and into the 21st century, with a memorial erected in Griffith, New South Wales in 1965 to commemorate the wheel and the Murrumbidgee Irrigation Area.

The wheel functioned by allowing water to pass under it, causing it to spin; the speed of rotations was measured to provide data on water volume. It was described as simple by faculty at Darmstadt University of Applied Sciences. In the 1950s, a quarterly review of irrigated dairy farms in Victoria noted that figures for water used had to be treated with reserve due to measurement difficulties even where Dethridge wheels were installed. The wheel was also used in the Murray-Darling Basin Area, which encompasses the Murray and Darling rivers.

Reader's Guide

The Dethridge wheel's significance lies in its role as a foundational tool for water measurement in irrigation, particularly in Australia, where it helped regulate water use in drought-prone regions. It was used in several countries and remained prevalent throughout the 20th century. However, by the early 21st century, it began to fall into obsolescence due to inaccuracies and environmental concerns. Research showed that the wheel's design caused water loss, with observations in Northern Victoria finding about 990 gigalitres of water lost annually. It was replaced by newer technologies such as FlumeGate and Total Channel Control systems, which aimed to provide more accurate measurement and reduce leakage. Despite this, the Dethridge wheel was also studied for potential use as a low head hydroelectric power generator, offering effects similar to a Zuppinger Wheel. Its legacy includes continued appreciation in Australia, and it was used as late as 1999 by CSIRO Land and Water to measure drainage volumes in Griffith, New South Wales. The transition to automation sparked controversy, with negative feedback from irrigators leaving the Victorian Government confused.

Did You Know?

• The Dethridge wheel was invented in 1910 by John Stewart Dethridge, the Victorian State and Water Supply Commissioner.
• A memorial to the Dethridge wheel was erected in Griffith, New South Wales, Australia in 1965.
• In the early 21st century, the Dethridge wheel was experimented with as a low head hydroelectric power generator.
• By 2002, Dethridge wheels were being replaced by FlumeGate technology as part of the Total Channel Control system in northern Victoria.