Dethridge’s invention, the Dethridge wheel – accurate for its time – measured the irrigation water taken and, in theory if not always in practice, ensured water was fairly distributed.
The practice of jamming the wheel, colloquially known as “spragging”, was not uncommon, allowing an irrigator to “steal” water by reducing the number of revolutions. (There are also references to raising the wheel axle for the same purpose.)
One cunning orchardist, known for his dislike of officialdom and being told what to do when it came to sourcing his water and food, often visited the Northern Rivers in western New South Wales.
There, while stringing (illegal) gill nets across its broad reaches, he would regularly snare freshwater turtles.
Having been foiled in his attempts at spragging with timber, steel and rope, he resorted to a natural sprag: “This should do the trick,” he was heard to say as yet another unwitting turtle, tucked in its shell, made the ultimate sacrifice at the stifled turn of a Dethridge wheel.
Another inventive landowner spragged his wheel with a fish.
He might have succeeded, had the fish – purchased from a local fishmonger – not been a saltwater variety, easily identified by the water bailiff during his rounds.
The demise of the water bailiff in modern-day electronic irrigation control is widely seen as the loss of an important point of rural tattle, social exchange, and farming contact.
