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Use of fathometers and electrical-conductivity probes to monitor riverbed scour at bridge piers

Water-Resources Investigations Report 94-4164
By:  and 
https://doi.org/10.3133/wri944164

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Abstract

Two methods, a fathometer system and an electrical- conductivity probe system, were developed to monitor scour at bridge piers. The scour-monitoring systems consisted of a sensor (fathometer or electrical- conductivity probe), power supply, data logger, relay, and system program. The fathometer system was installed and tested at a bridge over the Leipsic River at Leipsic, Delaware, and at a bridge over Sinepuxent Bay near Ocean City. Maryland. Field data collected indicate that fathometers can be used to identify and monitor the riverbed elevation if post processing of the data and trends in the data are used to determine the riverbed location in relation to the transducer. The accuracy of the system is approximately the same as the resolution of the fathometer. Signal scatter can be a major source of error in the data. The electrical- conductivity probe system was installed and tested at a bridge over the Pamunkey River near Hanover, Virginia. The approximate elevation of the riverbed is determined by comparing conductivities of the surface-water flow with conductivities of submerged bed material from sensors located in each. Field data collected indicate that an electrical- conductivity probe, as tested, has limited usefulness in identifying and monitoring the riverbed elevation during high flows. As the discharge increases, the concentration of sediment in the surface-water flow increases, especially near the riverbed. Conductivities, measured at the sensors in the surface-water flow could not be distinguished from conductivities measured at the shallowest sensor in the submerged bed material.

Suggested Citation

Hayes, D.C., Drummond, F., 1995, Use of fathometers and electrical-conductivity probes to monitor riverbed scour at bridge piers: U.S. Geological Survey Water-Resources Investigations Report 94-4164, iv, 17 p. :ill., map ;28 cm., https://doi.org/10.3133/wri944164.

Publication type Report
Publication Subtype USGS Numbered Series
Title Use of fathometers and electrical-conductivity probes to monitor riverbed scour at bridge piers
Series title Water-Resources Investigations Report
Series number 94-4164
DOI 10.3133/wri944164
Year Published 1995
Language ENGLISH
Publisher U.S. Geological Survey ; USGS Earth Science Information Center, Open-File Reports Section [distributor],
Description iv, 17 p. :ill., map ;28 cm.
Additional publication details