This document reports on results of research to develop a method for estimating depth of local scour at bridge piers that would provide an improved estimate from current methodology, i.e., one (or more) based on sand bed streams.
Field measurements of local scour at/near bridge piers were made at six sites in Washington State. These were to verify a method of estimating scour developed by earlier research at the University of Auckland (UAK). Stream flow rates witnessed at the sites were insufficient to compare actual scour with that estimated by the UAK method. That method currently is used for design of bridges in New Zealand.
The UAK methodology was used with field data to identify what scour might be expected under streamflows up to once-in-one-hundred-year discharges. The results of computations are given but they should be used with caution because of the assumed nature of streamflow variables.