Details:

Corporate Creators:
United States. Department of Transportation. Federal Highway Administration
Contributors:
Heier, Ammon
Subject/TRT Terms:
[+]
Case Studies Disaster Relief Disaster Resilience Floods Watersheds
Publication/ Report Number:
FHWA-HIF-23-023
Resource Type:
Brief
Geographical Coverage:
Arizona
Corporate Publisher:
United States. Department of Transportation. Federal Highway Administration
Abstract:
The Beaver Dam Wash is a seasonal stream that drains a watershed of over 600 square miles in Arizona, Utah, and Nevada. The area is characterized by high bluffs, erodible soil, and deep river channels, which makes it susceptible to flooding. In 2004-2005, the region experienced an unusually warm winter. Heavy rains swept through the area in early winter. In February 2005, 3.0 inches of rain fell, 2.2 inches above average, making it the fifth-wettest February on record in the region. The rains fell on an above-average snowpack in the surrounding mountains, which was 50% larger than normal. The rain and subsequent mild temperatures quickly melted the snowpack, causing major floods on the Beaver Dam Wash. The flooding damaged residences, businesses, and infrastructure in communities within Mohave County, Arizona. The flood washed out the southern approach to the Beaver Dam Wash Bridge that carries County Road 91. The waters also scoured the piers; uprooted trees, causing further damage; and almost overtopped the bridge. Erosion and the uprooted trees shifted the channel path upstream, which put the bridge in the main channel of the stream and exposed it to greater potential damage. The Beaver Dam Wash Bridge is a critical link in the community of Beaver Dam. It serves homes, a gas station, a convenience store, a railroad maintenance yard, and a firehouse on either side of the bridge. Students living south of the bridge reach an elementary school and a high school located on the north side. Immediately following the storm, Mohave County constructed a temporary access road to the bridge as an emergency repair under the Federal Highway Administration (FHWA) Emergency Relief (ER) program. The bridge was re-opened but was placed under weight restriction and remained at risk of failure from future storms. Mohave County concluded that the bridge repair required resilience upgrades for three reasons. First, the Beaver Dam Wash basin is prone to flooding and hazardous erosion of the banks. Second, the February 2005 flood compromised the bridge’s structural integrity. Third, the flood realigned the stream in a manner that put the bridge at even greater risk in a future flood event.
Format:
PDF
Collection(s):
Federal Highway Administration
Main Document Checksum:
[+]
urn:sha256:b6eb1c0c1b14505816aec4a0976b5eefafe6792d573bf1f92815ace9144f222f
Download URL:
https://rosap.ntl.bts.gov/view/dot/72762/dot_72762_DS1.pdf
File Type:

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