Authors / CoAuthors
Halas, L. | Magee, J. | Gibson, D. | Clarke, J.D.A. | Lawrie, K.C.
Abstract
In this study, a 1 m resolution LiDAR Digital Elevation Model (DEM) has been used for predictive flood modelling and flood-risk assessment that will inform recharge studies. To produce accurate predictions of flood inundation and calculations of flood volume, the DEM was initially levelled to the Darling River floodplain by subtracting interpolated floodplain elevation trend surface from the DEM. This produces a de-trended floodplain surface. Secondly, the levelled DEM surface was adjusted to the water level reading at the Darling River gauging station (Site 425012), upstream of Weir 32, at the time when the LiDAR was acquired. Flood extents were derived by elevation slicing of the adjusted levelled DEM up to any chosen river level. River-level readings from historical and current events were extracted from the NSW Office of Water real time river data website. The flood-depth dataset is an inverted version of the flood extent grid. Predicted flood depth and extent were classified by depth/elevation slice ranges of the adjusted de-trended DEM with 25 and 50 cm increments. Predicted flood extents have been validated by comparisons to satellite images from the 1990 floods, and photographs of inundation from recent flood events. In all cases imagery and photo validation proved that predicted extents are accurate. The flood-risk predictions were then applied to a number of river level scenarios. These included (1) examination of the extent of flooding at the highest historical level; (2) determination of the river level required to completely inundate the Coonambidgal Formation scroll plain in the GWMAR1 study area (probable maximum recharge potential) and (3) an assessment of flood impacts in 0.5 m increments from 5.5 to 7 m of river level rise at the Site 425012 gauging station. In summary, this flood modelling methodology has been used to predict the extent and depth of water coverage across the Darling floodplain under different scenarios.
Product Type
nonGeographicDataset
eCat Id
71331
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
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Keywords
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- External PublicationConference Paper
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- flood
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- DEM
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- GIS
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- mapping
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
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2010-01-01T00:00:00
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