Photogrammetry Techniques Used to Investigate River Processes and Novel Vegetation Management Methods; Luke Javernick

¹River Science

 

 

Flow regulation and water abstractions may change the complex relationship between river hydraulics, morphology, and riparian vegetation. As a result, rivers are likely to decrease their dynamics, increase the amount of vegetation, and modify their habitat structure. Flood events may provide a natural mechanism for removal of invasive vegetation and re-creation of natural floodplain habitats. This work used digital photogrammetry (Structure-from-Motion) to evaluate and quantifying how gravel-bed braided rivers naturally control vegetation encroachment through morphological processes and the impact of both naturally occurring and manipulated avulsions. Flume experiments evaluated low-, medium-, and large-flood events and documented morphological changes and impacts to vegetation at four intervals during the experiments. Vegetation dynamics are highly variable and depends on local morphological changes and bank erosion. Results showed that small flood events with manipulated avulsion can produce similar vegetation removal and morphologic changes as large floods without avulsion. These observations suggest that river managers and restoration efforts can have greater impacts on degraded or vegetation encroached rivers despite lower flow rates.