Minnesota Water Resources Conference - Water Resources Center ...

BOOK OF ABSTRACTS
Wednesday, Tuesday, October 24 28 23
Concurrent Sessions VI 3:00–4:30
Track D: Flood Reduction and Riverine Habitat, continued
Non-Invasive Solution to Prevent Flooding in the North Platte River at North Platte, Nebraska to Allow
for Increased River Flows During the Migratory Season
Rocky Keehn, Short Elliott Hendrickson, Inc., rkeehn@sehinc.com
In April 2007 SEH began plans and specification of a project to increase flow rates through about two miles
of the North Platte River in Nebraska upstream of the Highway 83 Bridge north of North Platte, Nebraska for
the Platte River Recovery Implementation Program (PRRIP). The PRRIP started in 1997 when the states of
Colorado, Wyoming and Nebraska and the Department of Interior came together in a unique partnership to
develop a shared approach to managing the Platte River. Water users from the three states and conservation
groups joined the effort and together, these stakeholders developed an innovative approach to better manage
the Platte for the health of the ecosystem and the people that depend on it. The PRRIP is the culmination of
that planning effort and is focused on implementing this shared vision for restoration on the Platte. One of the
Program elements is enhancing, restoring and protecting least tern, piping plover, and whooping crane habitat
lands which includes doing a “pulse” flow which are a result of controlled flow releases from Kingsley Dam
during the migratory season.
The SEH project was to be the first construction project to be completed by the PRRIP to allow for the pulse
flows to occur in the river during key migratory times. The project (as identified in a previous study not
completed by SEH) was to be an over one-half million dollar “ditch” improvement project which should prevent
flooding of several homes upstream of the Highway 83 bridge north of North Platte, Nebraska during the pulse.
flow. During the initial reconnaissance stages of the project to collect survey data, it was discovered that the
original proposed project would not be able to be completed due to issues with the landowners and permit
requirements. SEH then began a revaluation of the original project components to determine if the goal of the
project, which was to allow for an increase flow in the river, could still be accomplished.
The project went from an engineered project (ditches) to one in which the problem was addressed through a
better understanding of the river flow system and the removal of the main problem that was reducing the flow,
phragmites (an invasive species that grows to over six feet tall and is as thick as a jungle and is blocking natural
flow path over sandbars and in floodplains in several rivers in Nebraska). The presentation will focus on several
areas including: discussion on correct data collection requirements (relate story of how stakeholders used in the
original study were not the right group to meet with), looking at non-invasive solutions to projects (phragmite
project eradication by helicopter which started in the fall of 2007 verses re-digging a bunch of channels), cost
savings of the project ( final project will save about $500,000) and impacts of invasive species on flow rates in
rivers which can impact flooding, flood studies and other natural species (very interesting results in HEC-RAS
modeling in the reach).
Minnesota Water Resources Conference, October 27–28, 2008 82