High resolution DEMs created from high precision instruments (e.g. total station, LiDaR) have become ubiquitous in the field of fluvial geomorphology. They allow a diverse range of spatially explicit analyses including 2D hydraulic models, floodplain vegetation dynamics and time series topographic change. While previous studies have assessed the quality of individual survey instruments, the intercomparison of survey technologies across a diverse range of stream reach types has not yet been examined. In this study, we quantified the relative quality of bare earth topography derived from an array of ground-based and remotely sensed survey techniques as well as quantified the effort and cost in conducting the surveys. Over the summer of 2010, six sample reaches of varying habitat complexity were surveyed in the Lemhi River Basin, Idaho, USA. Complete, separate topographic surveys were attempted at each site using rtkGPS, total station, discrete return ground-based LiDaR, and infrared multi-return airborne LiDaR. The precision and accuracy of derived bare earth DEMs was evaluated relative to total station point data. Significant DEM differences (i.e. 95% confidence limit) between pairwise techniques were calculated using propagated DEM errors approximated by fuzzy inference systems. The results are helpful for understanding the strengths and weaknesses of different approaches in specific conditions, and how a hybrid of data acquisition methods can be used to build a more complete representation of channel topography.
Available at: http://works.bepress.com/joseph_wheaton/90/