Home Archived January 13, 2017
(i)

Potential Drift Accumulation at Bridges

Purpose and Scope

This report has two main purposes: (1) to provide a general description of drift characteristics and drift-related problems, and (2) to present an example of guidelines to assess the potential for drift accumulation at specific bridges, whether existing or under design.

The first component of the present study is a comprehensive review of the literature on drift and drift-related topics. The primary topics addressed in this literature review are:

Data collection for this study was international in geographic scope. Data were compiled for drift accumulations in 33 States and the District of Columbia; Puerto Rico; Manitoba and Saskatchewan; Malawi; and New Zealand (table 1). State Departments of Transportation in Indiana, Massachusetts, Maryland, South Carolina, and Tennessee cooperated with the USGS in potential-scour studies used as data sources in this study (figure 1). State Departments of Transportation in Arkansas, Delaware, Florida, Georgia, Idaho, New Mexico, North Carolina, Oregon, Pennsylvania, Virginia, and Wisconsin responded to a request for reports on drift accumulations (figure 2). Field studies were conducted in 11 States and the District of Columbia (figure 3). Data on accumulations in other States were obtained from publications and from written and oral communications (figure 4).

Several issues related to drift are outside the scope of this report:

Table 1. Sources of drift data by State [--, no data].

State, province, commonwealth, or country Number of sites of drift accumulation from: Total by State, province, commonwealth, or country

Scour-potential studies

Reports from States Field studies Publications and communications
Alabama -- -- 1 -- 1
Alaska -- -- -- 7 7
Arizona -- -- -- 1 1
Arkansas -- 55 -- 3 58
California -- -- -- 4 4
Delaware -- 1 -- -- 1
Florida -- 2 -- -- 2
Georgia -- 2 3 -- 5
Idaho -- 2 -- 1 3
Illinois -- -- 2 2 4
Indiana 270 -- 12 8 290
Louisiana -- -- -- 12 12
Maryland 122 -- -- -- 122
Massachusetts 54 -- 13 -- 67
Mississippi -- -- 2 2 4
Missouri -- -- -- 1 1
Nevada -- -- -- 2 2
New Mexico -- 23 -- -- 23
New York -- -- 5 4 9
North Carolina -- 2 -- -- 2
North Dakota -- -- -- 1 1
Ohio -- -- -- 1 1
Oklahoma -- -- -- 1 1
Oregon -- 3 -- 1 4
Pennsylvania -- 3 -- 10 13
South Carolina 1,053 -- -- -- 1,053
South Dakota -- -- -- 6 6
Tennessee 802 -- 66 4 872
Texas -- -- 12 11 23
Virginia -- 54 -- 12 66
Washington -- -- 23 5 28
Wisconsin -- 8 4 -- 12
Wyoming -- -- -- 1 1
District of Columbia -- -- 1 -- 1
Puerto Rico -- 3 -- -- 3
Manitoba -- -- -- 3 3
Saskatchewan -- -- -- 1 1
Malawi -- -- -- 1 1
New Zealand -- -- -- 13 13


TOTAL BY SOURCE


2,301


158


144


118


2,721

map with MD, MA, IN, TN, SC highlighted

6K GIF version of this map

Figure 1. Map showing States with potential-scour study data used in
this study.

map of drift sites reported by States

7K GIF version of this map

Figure 2. Generalized map of drift sites reported by States in response
to request.

Field sites studied by author

6K GIF version of this map

Figure 3. Generalized map of drift field-study sites.

previously published drift sites

7K GIF version of this map

Figure 4. Generalized map of drift sites in the United States from
publications and written and oral communications.

previous || table of contents || next

U.S. Department of the Interior, U.S. Geological Survey
Maintainer:webmaster@tn.water.usgs.gov
Last update: Tuesday, 08-Jan-2013 14:46:22 EST
URL: http://tn.water.usgs.gov /publications/FHWA-RD-97-028/purpscop.htm
USGS Privacy Policy || Disclaimer