Title :
Remotely sensed determination of flood surface gradients for hydrological modelling of semi-arid floodplains
Author :
Benger, Simon N.
Author_Institution :
Appl. Ecology Res. Group, Univ. of Canberra, ACT, Australia
Abstract :
The wetland and riparian communities associated with most inland Australian rivers rely on periodic flooding and drying cycles for their healthy maintenance and ecological functioning. Community composition, structure and location are determined primarily by elevation and hence access to flood waters. As most inland rivers are heavily regulated, determination of the timing and size of environmental flow releases from water storages is essential for the proper management of these areas. Modelling of flood surface gradients across large floodplains is one means used to determine which areas of the floodplain and consequently which vegetation communities will be flooded for a given environmental flow release. Traditionally, these gradients have been determined by cell-based analysis using aerial photography and contour maps. Various Landsat TM derived water detection algorithms and L-band SAR backscatter thresholding techniques were explored to detect floodwater boundaries during flooding of a large wetland area on the Macquarie River in central western New South Wales, Australia. These were used in conjunction with a Digital Elevation Model of the area in a GIS environment to model the flood surface gradient and determine the relationships between elevation, flooding and distance from flood entry point. Results showed that automated determination of the flood surface gradient from the satellite imagery achieved better results than manual cell-based analysis and facilitated more accurate modelling of the effects of flow releases. The development of such techniques will permit better use of water resources for sustainable management of important wetland and riparian communities in the future.
Keywords :
backscatter; ecology; floods; geographic information systems; hydrological techniques; radar detection; remote sensing by radar; rivers; synthetic aperture radar; vegetation mapping; water resources; water storage; Australia; GIS; L-band SAR backscatter thresholding techniques; Landsat TM; Macquarie river; aerial photography; cell-based analysis; central western New South Wales; community composition; contour maps; digital elevation model; drying cycles; ecological functioning; environmental flow release; flood surface gradient; flood surface gradients; flood waters; floodplains; floodwater boundaries detection; graphical information system; hydrological modelling; inland Australian rivers; periodic flooding; remotely sensed determination; riparian communities; satellite imagery; semi-arid floodplains; sustainable management; synthetic aperture radar; vegetation communities; water detection algorithms; water resources; water storages; wetland area; wetland communities; Australia; Biological system modeling; Environmental management; Floods; Photography; Rivers; Satellites; Timing; Vegetation mapping; Water storage;
Conference_Titel :
Geoscience and Remote Sensing Symposium, 2003. IGARSS '03. Proceedings. 2003 IEEE International
Print_ISBN :
0-7803-7929-2
DOI :
10.1109/IGARSS.2003.1294642