Iowa DOT to implement flood mitigation measures for Iowa 175 near Onawa
June 25th, 2011 by Ric Hanson
AMES, Iowa – June 24, 2011 – The Iowa Department of Transportation (DOT) will be
implementing flood mitigation measures along Iowa 175 to help keep the road open as
long as possible. This road is an important transportation connection between Onawa,
Iowa, and Decatur, Neb., as well as other communities along the Interstate 29
The success of these mitigation strategies remains dependent on the level of
continued rising river and ground water levels. They are being deployed at this time
due to the increased release of water by the U.S. Army Corps of Engineers, which is
projected to raise river water elevations from .5 to 1 foot. Those levels would
cause inundation of portions of the roadway.
Preliminary sandbagging will be performed this weekend along the shoulders of the
roadway in lower-lying areas. Starting Monday, additional measures will be taken to
address a rise in river water levels of up to 1 foot.
If water levels exceed 1 foot, conditions will be created within the overall basin
area that will make it impossible to contain the water and keep the roadway open. In
that event, the roadway will be closed.
An additional benefit of these mitigation strategies is the fact that it may allow
the roadway to be reopened sooner, if closed.
Next week, contractor employees will be placing sandbags and concrete barrier wall
along the west side of Cashew Avenue. In addition, sandbags and barrier wall will be
placed along the north side of Iowa 175. The lowest-lying areas will be the target
of the sandbagging effort.
The Iowa DOT has already strengthened the shoulders of the north side of Iowa 175 at
certain locations to help mitigate damage to the roadway surface.