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dc.contributor.authorFrazier, Paul
dc.contributor.authorRyder, Darren
dc.contributor.authorSouthwell, Mark
dc.contributor.authorYing Tsoi, Wing
dc.contributor.authorButler, Gavin
dc.contributor.authorCarpenter-Bundhoo, Luke
dc.contributor.authorHill, Ronnie
dc.contributor.authorvan der Veer, Nathalie
dc.contributor.authorBurch, Linden
dc.contributor.authorMace, Nathalie
dc.date.accessioned2022-12-05T03:35:32Z
dc.date.available2022-12-05T03:35:32Z
dc.date.issued2017
dc.identifier.urihttp://hdl.handle.net/10072/419961
dc.description.abstractThe Gwydir catchment, located in the northern Murray Darling Basin, extends from the Great Dividing Range west to the Barwon River. Downstream of Moree, the system fans out into a broad alluvial nearterminal floodplain. Numerous anabranches and distributary channels characterise the lower half of the Gwydir catchment, with the Mehi River and Moomin Creek to the south, and the lower Gwydir River, Gingham watercourse and Carole Creek to the north. These channels support wetland and floodplain assets including the Lower Gwydir, Gingham and Mallowa wetlands. Commonwealth environmental watering targets channel, wetland and floodplain assets with expected environmental outcomes downstream (west) of Tareelaroi Weir on the Gwydir River. Commonwealth environmental water was delivered to the channels of the lower Gwydir system and wetlands throughout the water year. While delivery to the Gingham and Lower Gwydir wetlands were a combination of both Commonwealth and State managed Environmental Contingency Allowance (ECA) water, in channel deliveries and deliveries to the Mallowa system were solely Commonwealth environmental water. This report considers the combined influence of both Commonwealth and State managed environmental water. These flows aimed to consolidate and protect the ongoing environmental recovery achieved to date in anticipation of a potentially low rainfall and inflow period. Environmental water was used to offset the component of consumptive extraction taken during several supplementary flow events and was also delivered to the Gingham and Lower Gwydir wetlands following natural flooding to maintain water levels, vegetation health and support waterbird and frog breeding. Environmental water was also delivered to the Mallowa system to provide connection and associated aquatic habitat and support vegetation communities. Key Outcomes Ecosystem functioning • Environmental water increased longitudinal connectivity in the Gwydir, lower Gwydir and Mehi River channels and was responsible for all significant flow in Mallowa Creek during 2016-17 • A total area of 3,234 ha of the Gingham and Gwydir wetlands was inundated in Spring 2016 as a result of a large unregulated flow event • In the Mallowa system, 901 ha of wetland was inundated with Commonwealth environmental water during 2016-17 • Semi-permanent wetland vegetation species such as water couch, spike-rush, tussock rush, lignum and river cooba, and floodplain species such as coolibah and river red gum were maintained during the 2016-17 water year. Water Quality • Environmental water deliveries improved water quality through the dilution of variables such as pH and conductivity and water nutrients such as nitrogen and phosphorus • Water column primary production appeared to be driven by temperature rather than high nutrient concentrations during 2016-17. Biodiversity • Environmental water influenced eight of the ten ecosystem types monitored in the LTIM project in the 2016-17 water year, including five riverine types, two floodplain types and one lacustrine type • Environmental flows maintained water levels in the Gingham Waterhole, which contains the only known local population of the olive perchlet, a threatened native fish species • Breeding and recruitment of native fish species was evident, with the threatened freshwater catfish recruiting for the first time in the LTIM project. Large scale breeding and recruitment of exotic species, carp and goldfish were also noted • Environmental water helped to increase invertebrate diversity and densities in wetland sites, providing food resources of native fish, waterbirds and frogs • 72 waterbird species were surveyed in 2016-17 across the lower Gwydir system. This represents the highest waterbird richness recorded in the project to date. Resilience • Environmental water helped maintain the condition of core wetland vegetation and conditions suitable for waterbirds and frogs to complete their breeding cycle • Low flow watering actions in March 2016 supported fish communities which had recovered during the wetter condition in 2016-17. Implications for Commonwealth environmental water management • The findings from the 2016-17 water year suggest that the current practice of using environmental water based on natural flow cues is working in the lower Gwydir river system, and more broadly that the long-term environmental watering strategy being employed in the Gwydir river system continues to be effective • A viable population of the threatened olive perchlet exists in the Gingham waterhole. This population should present a target for future environmental water delivery to try and maintain suitable conditions in the waterhole and promote their dispersal to other nearby waterholes if possible • Invertebrate communities and primary production respond to flow differently in the Gingham and Lower Gwydir wetlands. Both systems should be targeted with environmental water to promote regional scale biodiversity and productivity. Repeated wet-dry cycles in the Gwydir wetlands stimulated microinvertebrate productivity to densities 15 times higher than the permanently inundated Gingham sites. This suggests multiple dry phases within the water year can stimulate microinvertebrates as an important food source for larval fish. • The association shown between increased river discharge and activity of freshwater catfish and Murray cod during the 2016-17 monitoring period provides an opportunity to inform a different approach to environmental water management in the lower Gwydir Basin. In future years, environmental water may be able to be released to stimulate and facilitate similar patterns of fish movement during August to November (breeding season). Releases could take the form of a short sharp stimulus flow pulse (below bankfull) in mid-August followed by a gradual decline in flow to a point where the main channel and primary benches remain inundated. This would provide a stimulus for fish breeding and allow access to breeding habitat.en_US
dc.languageEnglishen_US
dc.publisherDepartment of Climate Change, Energy, the Environment and Wateren_US
dc.publisher.placeArmidale, Australiaen_US
dc.publisher.urihttps://www.dcceew.gov.au/water/cewo/publicationsen_US
dc.relation.ispartofpagefrom1en_US
dc.relation.ispartofpageto20en_US
dc.subject.fieldofresearchEnvironmental managementen_US
dc.subject.fieldofresearchcode4104en_US
dc.titleCommonwealth Environmental Water Office Long Term Intervention Monitoring Project Gwydir River System Selected Area – 2016-17 Annual Evaluation Reporten_US
dc.typeReporten_US
dcterms.bibliographicCitationFrazier, P; Ryder, D; Southwell, M; Ying Tsoi, W; Butler, G; Carpenter-Bundhoo, L; Hill, R; van der Veer, N; Burch, L; Mace, N, Commonwealth Environmental Water Office Long Term Intervention Monitoring Project Gwydir River System Selected Area – 2016-17 Annual Evaluation Report, 2017, pp. 1-20en_US
dcterms.licensehttp://creativecommons.org/licenses/by/3.0/au/en_US
dc.date.updated2022-12-05T01:12:25Z
dc.description.versionVersion of Record (VoR)en_US
gro.rights.copyright© Copyright Commonwealth of Australia, 2017. Commonwealth Environmental Water Office Long Term Intervention Monitoring Project Gwydir River System Selected Area is licensed by the Commonwealth of Australia for use under a Creative Commons By Attribution 3.0 Australia licence with the exception of the Coat of Arms of the Commonwealth of Australia, the logo of the agency responsible for publishing the report, content supplied by third parties, and any images depicting people. For licence conditions see: http://creativecommons.org/licenses/by/3.0/au/en_US
gro.hasfulltextFull Text
gro.griffith.authorCarpenter-Bundhoo, Luke P.


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