Digital mapping of riverine waterway hydrodynamic and geomorphic features

This paper proposes an innovative, non-intrusive method for mapping waterway characteristics in riverine areas. The technique uses photogrammetry to provide quantitative information about the dry area in the vicinity of the waterways (banks and floodplain) and image processing algorithms to characterize the flow. Riverside images of a riverine area are decomposed into quasi-planar areas and ortho-rectified and re-assembled to obtain a panoramic ortho-view of the area of interest. Morphological features of interest (such as river bank positions, flood plain edges, mud deposits, vegetation and erosion patterns) are then identified on the ortho-view and mapped digitally. Image sequences of the river flow are recorded, allowing a surface velocity analysis to be obtained through Large Scale Particle Image Velocimetry (LSPIV). Finally, the mapped elements and the surface velocities are displayed together in a GIS-like visualization. Through the presentation of a case study of a flood event at a culvert site, this paper demonstrates the capability of the technique to monitor characteristics of waterways over time. The method is inexpensive (a conventional video or digital camera can be used), fast and requires minimum preparation. It can be applied in such important river-related research areas as morphodynamic and sediment transport studies. It also fosters an improved understanding of the coupling between the river and its banks, which is essential for river restoration and eco-habitat studies. The present methodology is readily available for implementation in routine bridge inspections, fitted with an easy-to-use graphical interface. Copyright (C) 2009 John Wiley & Sons, Ltd.