Geomorphic Process from Topographic FormData & Models

The repeat topographic datasets used here are digital surface models (DSMs) derived using automated photogrammetry from photographs captured via aerial overflights during May 2002, 2009, and 2013. During overflights, discharge from Glen Canyon dam was held steady at 226 m3/s, and all subsequent analyses presented here apply to stages above this constant low flow discharge. DSMs are unique from traditional digital elevation models (DEMs) in that DSMs are not processed to remove vegetation. To compute geomorphic change during the inter-survey period, we used the Geomorphic Change Detection 6 software (http://gcd.joewheaton.org; see Wheaton et al., 2010). We assessed elevation uncertainty in the DSMs and found that uncertainty was spatially variable and significantly influenced by both surface slope and roughness, and thus employed a fuzzy inference system (FIS) to estimate DSM uncertainty on a pixel-by-pixel basis. Full details on the theory and implementation of FIS error modeling can be found in Wheaton et al., 2010, 2013, Kasprak et al., 2015, and Bangen et al., 2016. These data and models are associated with the journal manuscript: Kasprak A., Caster J., Bangen S., and Sankey J., 2017, Geomorphic process from topographic form: automating the interpretation of repeat survey data in river valleys: Earth Surface Processes and Landforms v. (online), doi: 10.1002/esp.4143, https://dx.doi.org/10.1002/esp.4143.