THE Southern Grampians Shire Council (SGSC) have taken some steps to control pond weed at the Hamilton Botanic Gardens, after some locals had expressed disappointment in the cleanliness and safety of some of its features.
The historical Thomson Fountain, now accompanied by the new rose garden display, had reports from residents to have looked dirty and slimy, whilst the Duck Pond under the bridge at the Gardens reported to have had an excessive amount of Duckweed (Lemna minor).
The common pond weed is a free-floating freshwater aquatic plant, formed on the surface of a slow-moving or stationary water body in nutrient rich conditions.
Duckweed is a native plant and can serve as an important food source for birds and aquatic animals and can have many benefits such as removing heavy metals like lead, copper, zinc and arsenic very efficiently from waters with non-lethal concentrations.
However, with a rapid growth rate, full coverage of a pond or dam by Duckweed can cause significant problems such as stopping oxygen diffusion, shading out all submerged vegetation preventing further growth, causing fish and other aquatic life death, and providing a breeding ground for mosquitos.
While some residents took their concerns to a Hamilton Community Facebook page, others claim to have spoken directly to the Council about the issue that has persisted for many years.
“Everything in moderation. It’s overgrown,” one wrote.
“Needs to be cleaned out and so do the lily pads or whatever they are.
“(It’s) not a natural waterway so you have to maintain it.”
“Duckweed can turn completely red, which is a big OHS issue, particularly as children may think its dirt and step on it,” one resident told The Spectator.
“Visitors expect to see water in a pond, not slime and pond weed,” another comment read.
“I appreciate all the volunteers who have done so much work at these places but if you can’t see any water, it’s a waste of time.”
An excessive amount of Duckweed can change the water chemistry to favour harmful algae and bacteria.
If left untreated, Duckweed can render the water unusable and make treatment far more costly than if initially dealt with.
A SGSC spokesperson said the Council had already started to undertake maintenance works on the duck pond with more planned in the near future to control the site.
“(Council) recently pulled a huge number of lilies out of the pond and began work to aerate the water,” they said.
“Finchetts plumbing will be adding an aerator system (this week) which should fix the problem.
“All in all, the issue is very much in hand and work should be complete soon.”
