Attenuation and Bottom-Reverberation Measurements in the Brazos River

Abstract

The use of high-frequency acoustic techniques for detection and study of submerged objects and geological features in rivers can be limited by both attenuation and reverberation. These parameters were measured in a pilot study of the lower reaches of the Brazos River near Houston, Tex. The attenuation was due to the suspended particulate matter carried by this muddy river. At a frequency of 200 kHz and for a particulate concentration of 0.025% by weight, the attenuation was found to be 1.5 dB/100 yd. Reverberation from the bottom sediment was measured at a frequency of 85 kHz as a function of transducer grazing angle. The reverberation data are interpreted as a scattering strength per unit area of bottom insonification and fall in the range of scattering strengths reported by others for fine mud. [This work was supported by the Office of Naval Research.]