Tanks for Platypus is Yarra Ranges Council’s program to install rainwater tanks on homes across the Monbulk Creek catchment, in Upwey, Tecoma, Belgrave, Belgrave Heights, Belgrave South and Selby. Water Studio is the engineer the program relies on for technical advice, particularly on charged tank systems.
Why tanks help platypus
Monbulk Creek has two problems for platypus. In summer its flows drop critically low, which limits food. In storms, runoff from roofs and roads sends sudden high flows down the creek that can flood young platypus in their burrows.
The tanks catch roof water that would otherwise rush down the drains, and use it for flushing toilets. They are also smart: they can release stored water to keep the creek flowing through dry spells, and draw down ahead of heavy rain so they have room to catch the runoff. Melbourne Water shared the network’s first release of environmental water as a milestone for the project.
The program is part of the Monbulk Creek Smart Water Network, jointly funded by the Australian Government, Melbourne Water and the Victorian Government, with support from the University of Melbourne, South East Water and Yarra Ranges Council.
Charged systems need an engineer
On many hills properties the downpipes can’t run straight into the top of a tank. A charged system solves this: the downpipes run below ground and connect to a pipe that stays full of water, so when it rains the water rises back up into the tank under the pressure of the water behind it.
The Building and Plumbing Commission has withdrawn the deemed-to-comply solution for charged tank systems. Without it, each charged connection needs a performance solution: an engineer has to show from first principles that the system will work and sign it off.
At the Puffing Billy Railway site in Belgrave, Water Studio inspected the site, checked the charged line hydraulically and added a flush-out point so the line can be drained when it needs cleaning. The flushed water is directed away from the tank and the building so it can’t undermine either. After inspecting the finished installation, Water Studio signed off the performance solution.
Getting a simple solution back
A simple charged tank connection shouldn’t need an engineer. It adds cost and time to every install, and programs like this one depend on getting many tanks in the ground. Through Jamie Tainton’s board role with ALDE (Association of Land Development Engineers), Water Studio is working with the Building and Plumbing Commission, DEECA and Master Plumbers to get a deemed-to-comply solution back in place.
About Tanks for Platypus on the Yarra Ranges Council website, including how Monbulk Creek property owners can take part.