High-resolution 3-D monitoring of evolving sediment beds

Key Points We describe a new technique for measuring the topography of evolving beds. The new technique was applied to a bridge scour experiment. The main advantage is the high spatiotemporal resolution. A new photogrammetric technique has been developed for monitoring the morphology of evolving stream beds. A pair of commercial cameras is used to record the evolution of the bed, and a computational approach that consists of a set of computer‐vision and image‐processing algorithms is employed to analyze the videos and reconstruct the instantaneous 3‐D surface of the bed. Time‐ and space‐resolved measurements are obtained to generate accurate representations of the bed. The required setup for the implementation of the technique is relatively simple and minimally intrusive. A thorough description of the algorithms that were used and detailed instructions for the implementation of the technique is provided. High‐resolution measurements of a gravel bed in a clear‐water, bridge scour experiment were carried out to demonstrate the operation and validate the capabilities of the technique. The new technique shows advantages compared to existing methods in terms of spatial resolution, temporal resolution, simplicity, and cost.