27 Aug Simon Hunter
Simon Hunter is a Senior Environmental Scientist with the Water and Wetlands Team, NSW Office of Environment and Heritage, Sydney. Since 2013, Simon has lead the ecological assessment work for the NSW Healthy Floodplains Project across six northern valleys in NSW’s Murray-Darling Basin – the Gwydir, Border Rivers, Upper Namoi, Lower Namoi, Macquarie, and the unregulated Barwon-Darling River valley. Simon has worked on a range of wetland projects for the NSW Office of Environment and Heritage, including the NSW Wetland Recovery Program and the Rivers Environmental Restoration Program (2006-2010). Simon holds a Master of Science and Technology (Spatial Information), University of New South Wales (2009) and a Bachelor of Applied Science – Resource and Environmental Science, University of Canberra (1997).
Protecting Flood Connectivity in the Upper Namoi River Valley Floodplain to Enhance the Health and Resilience of Floodplain Wetlands and Riverine Ecosystems
The Upper Namoi Valley floodplain including the rich black alluvial soils of the Liverpool Plains is one of the most fertile and productive agricultural areas in Australia.
Floods support agricultural production and replenish wetlands, including the nationally significant Goran Lake which provides refuge for migratory waterbirds travelling from the northern hemisphere.
Since the 1960’s, flood works have been constructed to protect broadacre cropping that has replaced historic sheep grazing and the Plains Grass grasslands of the Liverpool Plains. These uncoordinated works have enhanced agricultural land; however, they may also have altered overland flow patterns and impacted the resilience of wetlands, riverine vegetation and habitats.
To protect the passage of flood water to wetlands and riverine ecosystems of this highly productive cropping region, a valley-wide floodplain management plan was developed by the Department of Industry – Water and the Office of Environment and Heritage under the NSW Healthy Floodplains Project. The plan uses management zones and rules to co-ordinate the development of new flood works and amendments to existing flood works. Funding for the project was provided by the Australian Government’s Sustainable Rural Water Use and Infrastructure Program as part of the implementation of the Murray-Darling Basin Plan.
The ecological criteria used in the plan to maintain flood connectivity across the floodplain from the Liverpool Range in the south-east to Narrabri in the north-west will be presented. In addition, an ecological and cultural protection zone covering 9,000 hectares will be described and is included in the plan to satisfy the environmental protection provisions of the Water Management Act 2000.
Focus will be on the approach taken to incorporate advancements in ecological knowledge and technology, including LiDAR derived Digital Elevation Models, hydraulic modelling and satellite imagery, to ensure a healthy Upper Namoi floodplain and maintaining flood connectivity to the Lower Namoi floodplain.
Valley-wide floodplain management plans in NSW’s northern Murray-Darling Basin: protecting and maintaining floodplain and wetland connectivity
The fertile soils and water resources made abundant during floods contribute to floodplains being some of the most productive lands in Australia. In rural floodplains in the northern Murray-Darling Basin, levee banks and other flood works have been built to further enhance agricultural productivity. These works have improved land used for grazing, dryland and irrigated cropping. However, when built in an uncoordinated way these works can change over-bank flood behaviour, including impacting on flood connectivity to floodplain wetlands that depend on flooding to maintain their ecological character. To protect the passage of flood water through 5.2 million hectares of flood-prone country, six rural floodplain management plans are being prepared for the northern valleys of the Murray-Darling Basin in NSW. The Department of Primary Industries, Water and the Office of Environment and Heritage are working together as part of the NSW Healthy Floodplains Project to make these plans under the Water Management Act 2000. The plans use management zones and rules to co-ordinate the development of new flood works and amendments to existing flood works. Funding for the project is provided by the Australian Government’s Sustainable Rural Water Use and Infrastructure Program as part of the implementation of the Murray-Darling Basin Plan in NSW. This presentation will provide examples from the plan made for the Gwydir Valley, including detailing the criteria used to map management zones across the extent of major flooding. Focus will be on the hydraulic criteria used to develop the floodway network and the ecological criteria used to protect riverine-floodplain connectivity important for conveying water to flood-dependent ecological assets. Key to the team’s success has been leveraging improvements in computers used for two-dimensional hydraulic modelling, liaising with officers managing licensed environmental water deliveries and using best-available ecological data and LiDAR derived Digital Elevation Models.