View article

Digital elevation models (DEMs) of river channels, built by interpolation between samples of topographic survey points, are widely used to represent surfaces and to derive land-surface parameters. Differencing between successive DEMs permits quantification of change, which in gravel-bed rivers is used to construct a morphological budget of lower bound estimates of sediment flux and bedstability surrogate. Choice of DEM interpolation method strongly influences DEM quality and realistic representation of channel forms. When comparing morphological budgets between multiple contrasting reaches, eg for rapid ecological appraisal, an effective and consistent means of DEM construction is required to avoid digitally generated inconsistencies. An appropriate interpolation method should be suitable for accurate representation of channels contrasting in substrate and hydraulic conditions, surveys of varying data …