"Pilot Study for Collection of Bridge Scour Data"

In Reply Refer To:                                  March 30, 1987
WGS-Mail Stop 415


Subject:  PUBLICATIONS--"Pilot Study for Collection of Bridge
                        Scour Data" by Robert D. Jarrett and
                        Jeanne M. Boyle

We are pleased to distribute this report which provides
information on the collection of data on scour around bridge
piers.  Scour around bridge piers is a serious problem on many
rivers.  Bridge failure commonly is attributed to undermining of
piers by scour.  A pilot study was conducted for the Federal
Highway Administration (FHWA) at selected bridge sites in Colorado
to develop and test guidelines for collecting scour data onsite
during high flows.  These guidelines potentially could be used to
conduct bridge-scour studies in conjunction with normal high-flow
measurements.  The methods tested are compatible with equipment
and procedures commonly used in the U.S. Geological Survey (USGS)
streamflow-gaging program.  Two alternative approaches for future,
proposed scour studies are indicated.  The type of approach
selected would depend on the objectives of the scour study and the
flow conditions in the study area.

FHWA and USGS personnel recognize that additional verification of
existing scour-prediction techniques around bridge piers is
required and that an improved understanding of scour processes is
needed.  Minimal onsite data presently are available for
understanding scour around bridge piers.  The FHWA recognizes that
complimenting existing flood measurements at bridge sites with
additional pier scour data would be very cost effective and would
utilize a valuable resource.

Several States have recently approached USGS Districts about our
interest in conducting scour studies.  The Office of Surface Water
is developing some guidance material in the form of typical
proposals and suggestions for work that might be considered.  We
will furnish this material to the Regional Surface Water
Specialists soon.

Additional copies of the report may be obtained from Patricia A.
Griffith, Water Resources Division, Colorado District, Mail Stop
415, Lakewood, Colorado.

                                   Verne R. Schneider
                                   Chief, Office of Surface Water


WRD Distribution:  FO-LS, SL