- Airborne LiDAR Bathymetry has not frequently been applied to shallow water riverbed mapping.
- In addition to depth, water clarity often prevents the use of ALB.
- A pilot project on the Yakima River demonstrated that ALB was an effective methodology.
Using airborne LiDAR to map the sea floor has been successfully accomplished for over 25 years. One of the key issues is clarity of the water. This requirement has prevented the use of Airborne LiDAR Bathymetry – ALB from being used in most riverine mapping projects.
In this relatively short paper from 2005 the authors describe a very successful pilot application of ALB to mapping the Yakima River in Washington state. Flow was controlled in such a way as to allow for settling of sediment producing a very clear water column. Maximum water depth was only 4.5 meters making the use of sonar or other traditional survey methods very difficult and dangerous. In addition these methods only produce transects or cross sections which then have to be interpolated.
In general the results were very promising under the controlled conditions that were established. The 2m x 2m ALB coverage provided much more detail than traditional methods. Comparison with ground truth revealed some issues, such as the presence of large boulders, but overall the pilot project demonstrated that it was feasible to apply ALB to shallow riverbed mapping projects.