Dynamics of shallow wakes on gravel-bed floodplains: dataset from field experiments

Abstract

Abstract. Natural dynamics of river floodplains are driven by the interaction of flow and patchy riparian vegetation, which has implications for riverbed morphology and diversity of riparian habitats. Fundamental mechanisms affecting the dynamics of flow in such systems are still not fully understood due to a lack of experimental data collected in natural environments that are free of scaling effects present in laboratory studies. Here we present a detailed dataset on hydrodynamics of shallow wake flows that develop behind solid and porous obstructions. The dataset was collected during a field experimental campaign carried out in a side branch of the gravel-bed Tagliamento River in Northeast Italy. The dataset consists of thirty experimental runs in which we varied the diameter of the surface-mounted obstruction, its solid volume fraction, and the porosity at the leading edge, the object's submergence, and the approach velocity. Each run included: (1) measurements of mean velocity and turbulence in the longitudinal transect through the centreline of the flow with up to 25–30 sampling locations, and from 8 to 10 lateral profiles measured at 14 locations; (2) detailed surveys of the free surface topography; and (3) flow visualizations and video-recordings of the wakes patterns using a drone. The field scale of the experimental setup, the precise control of the approaching velocity, configuration of models, and the natural gravel-bed context for this experiment makes this data set unique. Besides enabling the examination of scaling effects, these data also allow the verification of numerical models and provide insight into the effects of driftwood accumulations on the dynamics of wakes. Data are made available as open access via the Zenodo portal (Shumilova et al. 2020) with DOI https://doi.org/10.5281/zenodo.3968748 .