Warrumbungle Raingarden

Protecting the Castlereagh River through best practice stormwater management

Two raingardens have been installed on Robertson Street, Coonabarabran to collect and slow stormwater while removing pollutants through a constructed biofiltration system.  This project will assist in protecting the Castlereagh River from erosion and contaminants contained in stormwater.  

The Castlereagh River is at the very heart of Coonabarabran and is integral to the recreation, amenity and ecology of the town.  The river has suffered from the negative effects of urbanisation over many years with severe bank erosion, weed infestation and influx of nutrients, sediments and other pollutants from stormwater run-off.  This project has involved the removal of woody weeds including willow, poplar and elm, rock armouring of a section of riverbank and the construction of two raingardens to collect, filter and slow stormwater prior to it entering the Castlereagh River.

This project targeted the rehabilitation of a severely eroded section of riverbank at the termination of Robertson Street, Coonabarabran.  The issue had resulted from stormwater collecting in the Robertson Street catchment, flowing through the kerb and gutter and resulting in high velocity water flows moving overland towards the river.  This resulted in severe erosion and river bank slumping.

To address the issue, the riverbank was rock armoured with the gully erosion leading to the river filled in to original soil levels with imported soil.  This addressed the symptoms of the problem but not the cause being the high velocity stormwater flows exiting Robertson Street.

In order to ensure that the problem would not reoccur two large raingardens have been installed to collect the stormwater as it exits the kerb and gutter on Robertson Street.  These raingardens have multiple benefits including:

• Collect and slow stormwater
• Filter stormwater to remove pollutants
• Installation of native riparian zone plant species
• Return filtered water to the river at reduced velocities

It is envisaged that this successful pilot project will pave the way for similar works in the region in the future.

For further information please contact:

Mick Callan
Project Support Officer
Environment & Waterways Alliance
PO Box 20
Bathurst NSW 2795
P: 02 6333 2323
M: 0400 968 201
mick.callan@lls.nsw.gov.au

-or-

Warrumbungle Shire Council
Technical Services
14-22 John Street
Coonabarabran NSW 2357
P: 02 6849 2000