The development of geoinformatics based framework to quantify gully erosin

In this study a methodological framework is presented using tools and techniques of geoinformatics to quantify gully erosion. The study was conducted in the Fergusson catchment; a sub-catchment of the Daly river, Northern Australia. Various airborne and field based reconnaissance surveys have shown that the catchment in places is severely affected by gully erosion producing large amounts of sediment. The framework applied comprised of Cartosat-1 (2.5 m resolution) stereo imagery 2008, topographic maps 1:20,000, 1 Second (~ 30m) SRTM level 2 DEM, Stereo Aerial Photos of 1948 at the scale of 1:30,000 and Differential GPS data points. Oriented images were produced using Image Analysis software and a Digital Surface Model was generated. Stereo Analyst for ArcGIS software was used for three dimensional visualization of the earth surface and identification and mapping of gullies. Stereo Aerial Photos of 1948 were orthorectified and three dimensional views were generated for each pair of photographs and a map of gullies in1948 was created. GIS based analysis was performed to measure the volumetric changes of gully erosion between 2008 imagery and 1948 aerial photographs. A spatial database was developed incorporating the gully morphological and soil loss information. This study will contribute to the construction of a sediment budget of the Daly River catchment.