The hotter the water temperature in a river the less oxygen that is carried. This can cause problems for certain fish species such as rainbow trout. The slower the river is flowing the more it heats up.
Idaho Power hired Quantum Spatial to map the Snake River using bathymetric lidar. In order to model the velocity of the river the contours of the river bottom must be known.
On of the challenges with topo bathy is the depth of penetration of the laser usually as a result of turbidity of the water. They really won’t know until the data is processed whether they were able to reach the bottom.