Tidal Restoration and Wetland Creation at the Kooragang Nature Reserve (Tomago, NSW)
Client: Department of the Environment and Climate Change (National Parks and Wildlife Service)
The Water Research Laboratory has been working with National Parks and Wildlife Service (NPWS) to restore tidal flushing and create a wetland in the Kooragang Nature Reserve. The wetland is being created to compensate for migratory wading bird habitat destroyed elsewhere in the lower Hunter River estuary.
Over several years WRL has been working with NPWS to develop, implement and monitor the restoration project. Led by Dr William Glamore, WRL has been involved in several stages of the project including:
- Initial wetland design (i.e. determining the wetland size/shape and tidal flushing extent)
- Hydrodynamic modelling of the existing and restored environments
- On-ground works to contain tidal flows to the designated areas (i.e. levees, culverts, etc)
- Soil, groundwater and surface water testing
- Development, testing and installation of a modified SmartGate system
- Wetland restoration trials
- Development of on-going monitoring programs including remote camera surveillance
The site is a large cleared floodplain with a large levee bund on the perimeter which excludes tidal flushing. Over the past 40 years the site has been used for agricultural and military purposes but is now part of the internationally recognised Kooragang Nature Reserve.
Numerical modelling of the site indicated that upstream landholders would be affected by the tidal waters if full tidal flushing was restored. To adequately control the tidal flushing, 4 SmartGate systems were installed. These gates automatically control tidal flushing based on real-time water level measurements. A range of culvert and levee structures were also installed around the site to control the extent of tidal flushing. Soil, groundwater and surface water measurements were undertaken to assist with the investigation.
In October 2008 the SmartGates were officially commissioned and tidal flushing was restored to >100 hectares. A detailed monitoring program is underway to determine the impact of the restoration works on surface water, groundwater, soils, flora and fauna. As part of the monitoring program a digital camera was installed on an 18 m pole. The camera provides high resolution images 5 times per day. Analysis of the images assists in counting birds, determining the salt marsh extent and assessing the evolution of the site with time. Further work is currently ongoing.
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