A COMPARISON OF HIGH-RESOLUTION TOPOGRAPHIC SURVEY METHODS TO ASSESS THE GEOMORPHIC EVOLUTION OF A [FORESTED] RIVER BEND : A SUITABILITY ANALYSIS

Topographic surveys of fluvial landforms provide valuable insights into ecological, environmental, infrastructure, and contaminant management. Study sites that require high-resolution surface models favor terrestrial laser scanning (TLS); however, this industry- and research-standard approach is unsuitable for budget-limited or large scale studies. A promising novel approach to high-resolution geospatial data collection, close range digital photogrammetry (CRDP), provides rapid and cost-effective results.In this study, we compare the use of TLS and CRDP to monitor the spatial patterns of erosion and deposition along a point bar in White Clay Creek, Newark, DE. A robust evaluation of the differences between CRDP and TLS surface models, as observed by conducting a time-series of annual surveys using both methods in tandem over three years and using variograms to quantify their spatial variability, shows that 1) the two methods produce dissimilar digital elevation models because 2) each method models bare earth, dry vegetation, and green vegetation differently. As such, 3) the resultant DEM’s-of-Difference between the two methods do not agree. Our preliminary results suggest that, at our field site, TLS-based DEMs accurately and precisely model the ground surface elevation of all land cover types tested, whereas CRDP does not. While TLS and CRDP produce statistically different surface models, the full suite of survey design considerations (i.e. desired spatial resolution, total project budget, and total billable field time) does not rule out CRDP as a heuristic survey method viable for real world applications