I use a Lowrance HDS Pro sonar to collect environmental data (variables) for my ecological survey. Beside some basic data it would be useful to involve the bottom composition data, distinguishing the different (e.g. muddy, sandy, gravel or rip-rap) sediment types of the longitudinal sampling sites. However, the 'returns range' either PeakSV, E1 or E2 seem rather refer to the depth than the quality of bottom. How returns range values can refer to sediment type? Is it possible to use returns range values or any other data to develop - at least a relative - variable, which can refer to the composition of the waterbed at the sampling site?

My expiriences with bottom hardness overlay show that it's tool limited because in deep lakes hard bottom is in bigest deep- as overlay, but in fact water pressure compressed sediment on top of the bottom, below- is very soft bottom layer. It's possible to view on SideScan Layer too- brighter parts of bottom on deep.
Second thing- fishing equipement isn't for bottom composition true analize. This need low frequenzy transducers, more output power form sonar module- to get penetration thru sediments and strong returns for much more advanced software than RM.