A Novel Method for Gaining New Insight on Flows Over Inundated Landscapes

We present a novel approach for detecting surface water flows over flooded terrain. The approach requires a minimum of three stage measurements and can be applied to any inundated surface, across a range of temporal and spatial scales. This method creates new and robust opportunities for field observation and for validation of numerical simulations and remote sensing analyses. In this proof-of-concept study, we found that floodplain free surface gradients were particularly variable during sub-bankfull inundation, including abrupt current reversals. Also, flow direction varied with stage and the rate of change in stage. The "triangular facet" approach provides a new type of mesoscale insight of flow processes over inundated landscapes, highlighting flow complexity. Moreover, the approach provides information on floods that represent a compromise between point velocimeter measurements and satellite remote sensing and it can provide substantial benefits to society by aiding in flood hazard and mitigation assessment and planning.