- Title
- Channel incision and sand compartmentalization in an Australian sandstone basin subject to high flood variability
- Creator
- Erskine, W. D.
- Relation
- International Symposium on Sediment Dynamics in Changing Environments. Sediment Dynamics in Changing Environments (Christchurch, NZ 1-5 December, 2008) p. 283-290
- Relation
- http://www.iahs.info
- Publisher
- International Association of Hydrological Sciences
- Resource Type
- conference paper
- Date
- 2008
- Description
- Wollombi Brook in the Hunter Valley, New South Wales, Australia, is characterised by high flood variability on a global scale (Flash Flood Magnitude Index of at least 0.86). Channel incision has occurred throughout the 2000-km² basin since initial European settlement in the early 1820s. On the main stream, discontinuous incision occurred in the upper basin in a 7-km long reach and was caused by the localised exceedence of a valley-floor slope threshold by a large flood in 1927. Since then, 900 000 m³ of valley fill has been eroded by knick-zone migration and subsequent channel widening, but the whole sand fraction has been deposited immediately downstream in a sand slug or intermediate floodout. Between 1927 and 1982, incision moved 7 km upstream, but has since stabilised due to engineering works. Non-synchronous incision of tributaries was recorded between 1838 and 1977, but the generated sand often did not reach the main stream because of deposition in intermediate floodouts/sand slugs on the tributaries. Incision of the largest tributary, Congewai Creek, was initiated by a catastrophic flood in June 1949, and was integrated with the main stream downstream of the intermediate floodout. Sand from Congewai Creek and Wollombi Brook, downstream of their junction, was transported continuously out of the basin until 1996 when channel recovery from the catastrophic 1949 flood was accelerated by substantial vegetation colonization and sand anchorage.
- Subject
- Wollombi Brook, NSW, Australia; chain of ponds; floodouts; sand slugs; sand compartment; channel recovery
- Identifier
- uon:6190
- Identifier
- http://hdl.handle.net/1959.13/802744
- Identifier
- ISBN:9781901502848
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