FLOOD04125

• County: Statewide
• Basin: Statewide
• Title: Interim Procedures for Evaluating Scour at Bridges
• Date: 9/1/1988
• Prepared By: Federal Highway Administration
• Floodplain - Doc Type: Educational/Technical/Reference Information

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Jarrett and Boyle (1986). The main objective ot tnis approach is to estimate
the depth of scour that occurs at a site tor the purpose of evaluating Scour
prediction equations. Measurement techniques are compatible with equipment
and procedures commonly used by the uses and other agencies in streamf1ow-
gaging activities. This "limited,approach" is also being applied in an on-
going USGS national bridie-scour study and other cooperative bridge-scour
studies being conducted by the USGS and some States. Therefore, the scour
data collected for this [==>study area<==) scour study will be compatible
with data base(s) of other scour studies.

Work Plan

The [==>study area<==) scour study will span a period of [==>yrs.,mos.<==].
It the magnitude and frequency of floods during the period are sufficient, the
project objectives should be achieved. [==)number<==) sites will be selected
for data collection. Assuming proper hydrologic conditions, attempts will be
made to collect onsite-highflow data at about [==>fraction<==) of the sites
per year. The r==>sponsoring agency<==) will participate in site selection to
aid in defining potential scour sites. Preferably, a siqniticant number of.
the sites can be located at or near streamflow-gaging stations where discharge
and velocity observations are available. Sites should have either SOIll form
of telemetry or sattelite transmission capabilites or be monitored by hired
station observers to ensure collection of data at or near peak flows. Data
will be collected over a (==>?-year<==) period, which should provide about
[==>??<==) total measurements and about (==>??,==) measurements at each site.

The entire project can be divided into three phases:

Phase I. - Reconnais$8nce, site selection, and site establishment;

Phase I!. - Annual data collection, annual data analysis, and annual
reporting; and

Phase III. - Final data coilection, final data analysis, and complete
final report.

Phase I.--Reconnaissance.

Lite,'ature review

A thorough review of current research, journal article$, and o_her technical
publications relating to bridge scour will be conducted. Special emphasis
will be given to what equations. are being used or recommended tor est1mati~g
scour depths.

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