|Shields Jr, Fletcher|
Submitted to: Journal of Hydraulic Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 24, 2009
Publication Date: May 1, 2010
Citation: Shields Jr, F.D. 2010. Aquatic Habitat Bottom Classification Using ADCP. Journal of Hydraulic Engineering. 136(5): 336-342. Interpretive Summary: Physical characteristics of riverine aquatic ecosystems vary continuously in time and space, and measuring the habitat quality of a given river segment usually requires collection of a large amount of data. An existing, widely used, commercially-available device for measuring river depths and velocities using acoustic echoes from the bed and from particles suspended in the water was used to classify bed sediment types by recording the strength of echoes from the bed. Mean signal strength from soft, muddy beds was consistently 10 to 20 dB lower than mean signal strength from noncohesive (gravel or sand) beds. Sand beds produced a wide range of signal strengths that were apparently related to the presence or absence of bed forms (dunes) and bed movement. These results will be useful for advancing the use of widely-available, relatively low cost technology for monitoring the quality of river habitats.
Technical Abstract: Description of physical aquatic habitat often includes data describing distributions of water depth, velocity and bed material type. Water depth and velocity in streams deeper than about 1 m may be continuously mapped using an acoustic Doppler current profiler from a moving boat. Herein we examine the potential of using the echo signal strength from the bed as an indicator of bed material type. Mean signal strength from soft, muddy beds was consistently 10 to 20 dB lower than mean signal strength from noncohesive (gravel or sand) beds. Sand beds tended to have larger site-to-site variation (means -30 to -19 dB) than for fines (-43 to -38 dB) or gravel (-23 to -20 dB).