May/June 2021 - 94

flood risk through a combination of
traditional infrastructure (e.g., levee
embankments and flood walls) and
nonstructural approaches. They
include local land use planning
measures and ordinances, flood
warning systems, and evacuation
planning and preparedness. In addition,
communities, states and tribes share
the costs of planning, designing and
building congressionally authorized
flood risk management projects and
usually bear full responsibility for
operating and maintaining these projects,
including levees.
The extrapolated portfolio cost to
Levee-related flooding in Kentucky in April 2011
To prevent overtopping, communities
sometimes place sandbags on top of
levees to increase their height. These
and other flood-fighting efforts can help
prevent a disaster; however, they do not
always succeed. Therefore, they should
be viewed as last-ditch steps rather than
a first line of defense. In addition, flood
fighting in one area may induce flooding
in another area.
Levees can be damaged in several
other ways. For instance, strong river
currents and waves can erode the
waterside surface of a levee. Debris and
ice carried by floodwaters - and even
large objects such as boats or barges -
can collide with and gouge a levee. Trees
growing on a levee can blow over,
leaving a hole where the root wad and
soil used to be. Or burrowing animals
can create holes that enable water to
pass through a levee. If severe enough,
any of these situations can lead to a
weakness that could cause a levee breach.
In the 100-+ years since the Flood
Control Act of 1917, the role of USACE
and the federal government has
changed. The responsibility for flood
risk management, which changed from
communities to the federal government
in the early twentieth century, now has
stabilized as a partnership and shared
responsibility.
94 * DEEP FOUNDATIONS * MAY/JUNE 2021
The most recent Energy and Water
Development and Related Agencies
Appropriations Act (WRDA) for fiscal
year 2021 provides $4.5 million for the
National Levee Safety Program. USACE
will use this to continue its inventory of
known levees systems. This is in addition
to the $15 million appropriated in
2020, but is still far short of the $79
million authorized for the program.
Local communities, states and tribes
share a responsibility with the federal
government to recognize and mitigate
address levee safety issues and improve
evacuation effectiveness for very high,
high and moderate risk levee systems
in the USACE portfolio go through a
wide range of budgetary and planning
processes to make the most costeffective
investment decisions for the
levee portfolio. In 2016, more than $700
million was expended to construct flood
risk management projects, including
new construction and remediation of
dams, levees and channels. Construction
and rehabilitation of levee-related
infrastructure represents about half of
this amount.
A June 2011 breach of Missouri River Levee L-575
May/June 2021

Table of Contents for the Digital Edition of May/June 2021
