Delaware’s Indian River Inlet Bridge OK after Irene

The Indian River Inlet Bridge remains safe following Hurricane Irene, according to an inspection conducted by The Delaware Department of Transportation.

Bridge inspectors completed both a fathometer survey and visual pier inspection Tuesday. A fathometer survey details the elevations of the channel bottom, including the area around the piers and the existing scour holes near the piers. 

Bridge Management Engineer Doug Finney explained the process.

“A fathometer is a device used to measure the depth of water using ultrasound waves,” he said. “The survey is done by recording water depths on a grid pattern over the area of interest.  This is used to determine the general shape of the channel bottom. For our bridge, this was done over the complete width of the inlet, extending 200 feet upstream and downstream from the bridge.”

The inspection confirmed that there are no significant changes to the channel bottom near the existing piers.

The survey of the channel bottom is the critical inspection to perform after a storm since it is the wave and tidal action that can cause scour around the piers, potentially causing instability.  DelDOT conducts this type of survey annually and after any significant storm event.   

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