OPERATIONAL MAPPING OF THE ENVIRONMENTAL CONDITION OF RIPARIAN ZONES OVER LARGE REGIONS FROM AIRBORNE LIDAR DATA

摘要

Riparian zones maintain water quality, support multiple geomorphic processes, contain significant biodiversity and also maintain the aesthetics of the landscape. Australian state and national government agencies responsible for managing riparian zones are planning missions for acquiring remotely sensed data covering the main streams in Victoria, New South Wales, and parts of Queensland and South Australia. The objectives of this paper are to: (1) assess the ability of LiDAR data for mapping the environmental condition of riparian zones; and (2) provide specifications for capturing and analyzing the LiDAR data for riparian zone mapping at large spatial extents (> 1000 km of stream length). LiDAR derived digital elevation models, terrain slope, intensity, fractional cover counts and canopy height models were used for mapping riparian condition indicators using simple algorithms and more complex object-oriented image analysis. The results showed that LiDAR data can be used to accurately map: water bodies (producer's accuracy velence 93percent); streambed width (Root Mean Square Error (RMSE) velence 3.3 m); bank-full width (RMSE velence 6.1 m); riparian zone width (RMSE velence 7.0 m); width of vegetation (RMSE velence 5.6 m); plant projective cover (RMSE velence 12percent); vegetation height classes (vertical accuracy < 0.20 m); large trees; longitudinal continuity; vegetation overhang; and bank stability (R~(2) velence 0.40). Suitable LiDAR data acquisition specifications are also provided.