Abstract: Disclosed is a method of detecting the bottom of a waterbody in the presence of overlying submersed aquatic vegetation (SAV) and of characterizing physical attributes of that overlying vegetation. A narrow-beam hydroacoustic transducer is mounted on a mobile survey boat in a vertically-downward orientation. A rapid series of short pulses (pings) are generated by the transducer as the boat traverses a predetermined path within the waterbody. Raw hydroacoustic echo-level data is digitally recorded along with position data generated by some electronic position measurement system. The methodology for processing the raw signal is implemented in a digital computer algorithm which extracts hydroacoustic signal features and applies classification decision rules which were developed based on common physical characteristics of aquatic environments containing SAV. An apparatus for carrying out this method is also disclosed.