Abstract: A method for determining a length of a pile which includes the steps of affixing a plurality of sound sensors in a vertical array adjacent to the pile, generating an elastic wave adjacent the pile such that the elastic wave propagates through or from the pile, radiating the elastic wave from the pile such that the sound sensors receive the radiated elastic wave, and analyzing the radiated elastic wave so as to determine the length of the pile. The elastic wave can be radiated so as to create upwardly propagating waves and downwardly propagating waves within the pile. The radiated elastic waves can also produce refracted elastic waves along a length of the pile and diffracted elastic waves at a bottom of the pile. The data from the radiated elastic waves is analyzed so as to be determinative of the length of the pile.

Abstract: A method and apparatus for measuring bottom scour adjacent a foundation structure extending into the bottom of a stream of flowing water is disclosed. An elastic wave source is used for transmitting elastic waves through the water, the scour zone, and the bottom adjacent the foundation structure. The elastic waves are transmitted directly to an array of receivers and indirectly through the foundation structure to produce refracted signals that also travel to the receivers. The array of receivers are adapted for substantially vertical positioning such that a portion of the receivers will sense elastic waves that travel through the water above the scour, a portion will sense elastic waves that travel through the scour, and a portion will sense elastic waves that travel through the bottom adjacent the structure. Means are utilized for recording the time required for the elastic waves to reach each receiver to measure the depth of scour next to the foundation structure.