Identification and analysis of step-pool morphometry : a study of geometric relations and spatial distributions in step-pools, following automated identification of bed morphology from a longitudinal profile
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- Institutt for geografi 
Global warming might increase water and sediment inputs to some river systems, and a better understanding of bed morphology and hydraulic resistance is required to adapt to future flows. The natural formation and morphometry of step-pools is valuable to understand such that river restoration projects can better replicate the necessary hydraulic resistance. Morphometry and spatial organization in the bed structure of a 1.8km long section of Vekveselva, Norway, is analysed to study characteristic dimensions and patterns of regularity in step placement. Step spacing is compared to those of random sequences, and relations between mean step properties are analysed. A custom algorithm is designed to automatically and objectively extract step-pool sequences. Results show that (1) step-locations are more clustered together than random distributions on some neighbourhood scales, and (2) the distribution of step spacings is statistically significantly different from a Poisson distribution. Large scale regularity (3) cannot be illustrated in morphometric relations between mean step properties such as step height, step spacing and local slope, indicating that local bed morphology affects step formation more than forced hydraulic deposition. No reach-scale trends in step formation can be shown.