Very-high-resolution mapping of river-immersed topography by remote sensing

Denis Feurer, Jean-Stéphane Bailly, Christian Puech, Yann Le Coarer, Alain A. Viau
2008 Progress in physical geography  
Remote sensing has been used to map river bathymetry for several decades. Non-contact methods are necessary in several cases: inaccessible rivers, large-scale depth mapping, very shallow rivers. The remote sensing techniques used for river bathymetry are reviewed. Frequently, these techniques have been developed for marine environment and have then been transposed to riverine environments. These techniques can be divided into two types: active remote sensing, such as ground penetrating radar
more » ... bathymetric lidar; or passive remote sensing, such as through-water photogrammetry and radiometric models. This last technique -which consists of fi nding a logarithmic relationship between river depth and image values -appears to be the most used. Fewer references exist for the other techniques, but lidar is an emerging technique. For each depth measurement method, we detail the physical principles and then a review of the results obtained in the fi eld. This review shows a lack of data for very shallow rivers, where a very high spatial resolution is needed. Moreover, the cost related to aerial image acquisition is often huge. Hence we propose an application of two techniques, radiometric models and through-water photogrammetry, with very high-resolution passive optical imagery, light platforms, and off-the-shelf cameras. We show that, in the case of the radiometric models, measurement is possible with a spatial fi ltering of about 1 m and a homogeneous river bottom. In contrast, with through-water photogrammetry, fi ne ground resolution and bottom textures are necessary.
doi:10.1177/0309133308096030 fatcat:56fszkkyyzcodjiex4bvsnfsxy