Drainage upgrades for Upper Deakin catchment

By Rodney Woods

A new, low-cost approach to drainage is being rolled out across parts of the Goulburn Valley with works under way near Stanhope.

The natural drainage course is being restored through the Upper Deakin catchment.

Taking advantage of the natural terrain, the new system known as hybrid drainage, is based on declaring drainage courses.

The work is being delivered by Goulburn-Murray Water and Goulburn Broken Catchment Management Authority.

Goulburn Broken CMA sustainable irrigation manager Carl Walters said declaring drainage courses was a cost-effective and more natural way to provide drainage in irrigation areas across the region.

“This type of system costs about a third of what we historically spent on building drains,” Mr Walters said.

“It’s a major shift from building drains, holes in the ground and structures.

“We will now use natural depressions and remove obstructions like roads and channels and other man-made structures to restore natural flow-paths.”

Mr Walters said the shift in approach was prompted by the changing needs of the region’s irrigators.

“We don’t really need to build drains anymore,” he said.

“There’s less irrigation being undertaken which means the irrigation footprint has changed.

“Therefore we have less run-off but when it rains heavily — and it will again — we need to be able to get that water off the land.”

The Upper Deakin catchment is located between Harston and Stanhope and was selected for the program after a strong push from irrigators to improve drainage.

G-MW's drainage program co-ordinator Carolyn Nigro said the new declaring drainage courses-based form of drainage was designed to connect and restore natural drainage lines.

“Traditional drainage hasn’t adapted to the way we irrigate now or to current farm practices,” she said.

“Now we are focused on connecting natural drainage lines and removing obstructions.

“Old drainage used to involve taking tail water from properties but these days people don’t want to waste water because it’s too precious a commodity now and they want to recycle it.”

She said heavy rain in the catchment in December 2017 proved to be a valuable tool and helped inform modelling and confirm potential obstructions to flow.