The important feature of GPR use that is to be mentioned - it can examine the structure of the bottom. I.e. there is possible to find underwater items located inside the bottom stratum. Also GPR can provide an information about the thickness of bottom silt or bottom ground, and its volume structure. The same exploration is very problematic if made by other means.
In the summer 2012 VIY3-300 GPR was examined as sub-bottom profiler. The tests were made in Kyiv, Ukraine. GPR was placed in a plastic tub and moved across the surface of the fresh water lake. The survey window number of 166 ns corresponds to the depth of 2.7 meters.
The signal reflected from the bottom is clearly visible on the profile. Compensation of the signal attenuation along increasing depth reached 60 dB. That indicates the water condition in an urban area. Fluctuation of GPR signal in the upper part of the profile is caused by the ripples on the water surface.
This GPR profile can be downloaded here: http://viy.ua/download/sample/Water_01.zip