Calibration of an ADP To Estimate Suspended Sand Concentrations in a Large River

SZUPIANY, R.N.; AMSLER, M.L.; GARCÍA, C.M.

Lake Placid, New York, USA.

Conferencia; Hydraulic Measurements and Experimental Methods Conference; 2007

Environmental and Water Resources Institute of ASCE (EWRI) y International Association of Hydraulic Engineering and Research (IAHR).

The standard procedures used for sampling suspended sands in large streams requirethe vessel to be anchored at a proper number of several verticals during a certainperiod of time. These methods are usually time-consuming, rather expensive, andhave a limited spatial resolution. Additionally, a potential risk for the vessel safetyexists in navigable rivers. The acoustic Doppler technology has been recognized as atool that may give quantitative information on suspended sediment concentrationsthrough the acoustic backscattering strength avoiding several drawbacks implicit inthe traditional methods. In this paper a relation between the backscatter acousticintensity recorded by an Acoustic Doppler Profiler (ADP) and suspended sandconcentrations obtained from classic depth-integrated samplings, is presented anddiscussed. The resulting relation compared fairly well with the theoretical straightline slope suggested by the ADP manufacturer. It is concluded that the similaritybetween the suspended sand sizes and the type of particles which present maximumsensitivity to the backscatter acoustic intensity according to the inherentcharacteristics of the ADP instrument used in this case, is a crucial issue to explainthe results consistency.