Would any of these show the depth of lakes in great detail? i.e. a LiDAR at 25cm, will it show the detail of the lake bed?
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sonar (Echo Sounding) is better than lidar for this if the device sending the sonar can be accurately measured with location (gps).en.wikipedia.org/wiki/Sonar#Echo_sounding– Mapperz ♦Commented Jun 15, 2020 at 21:41
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Standard LiDAR collectors do not do a good job at measuring water depth; they aren't designed to. The pulses are often either reflected in a different direction or absorbed by the water feature. The only pulses are returned to the sensor are those that are perpendicular to the water's surface. Except for some very shallow features in relatively clear water, the pulse returned often represents the surface.
To map a lake bed you would want to conduct a bathymetric survey, using sensors designed for that specific purpose. The sensor would use wavelengths optimized for penetrating surface water and its contaminants. Even then its effectiveness is limited. The best results from a bathymetric LiDAR sensor I've heard of is only up to two times Secchi depth.
