FLOOD01312

• County: Statewide
• Title: Multi-Objective Flood Mitigation Plan for Vermillion River Basin-South Dakota
• Date: 1/1/1994
• Prepared For: South Dakota
• Prepared By: FEMA
• Floodplain - Doc Type: Flood Mitigation/Flood Warning/Watershed Restoration

IX'Pular, and many additional activities are avail-
able at East Vermillion Lake, which receives a
heavy influx of visitors from the Sioux Falls met-
ropolitan area. Basin residents go down to the
MisSQuri River for boating, swimming, camp-
ing, and picnicking because recreation
resources and access are more readily avaiJ.
able there than along the Vermillion River.

THE #lTUATION

Like all bodies of water, the Vermillion River
naturally overflows its banks from time to
time. This results in acute and chronic flood-
ing that is typical of many rural, agricultural
basins throughout the country. The low topo-
graphic relief; local land use practices; the rates
of preripitltion, ev.Jporation.transpiration, and
runoff; freeze/thaw cycles. and groundw31er
tables all contribute to the intensity of floods.
The ll00dwaters inundate farmlands. impede
agricultur.lI drainage and community storm-
water runoff, damage roads., and enter homes
and hu~i~ Measured in monetary terms,
most of the damage is done to agricultural

operations, and some is suffered by the small
tOwns that dot the fanning landscape.
It is commonly believed that flooding in
the Basin is getting worse. but there is really
no way to compare present conditions to floods
that occurred 15, SO, or 200 years ago. In all
probability. some human activities have con.
tributed to the flood proo\em-unsui.tahle

land use practices, people Jiving in lhe rivers
tloodplains and low areas, and natural flood
storage areas (wetlands) that haV(' been
drained. for example. It is also possible that a
meteorological "wet cyde~ is taking place.
Probably the true "cause" is some combination
of all these things, and others.
Ovt'r the pa~t few decades. many attempts
have bten m.Jde to al\evi.ate the nO\.'>din~ in the
Vennillion Ilasin; many other ideas have been
suggested but not adopted or carried out. The
river h.u been channelized from about II miles
below Centervillc to 2 miJes above Vennillion.
There are over 50 milcs offevees on both sidcs
of the lower Vennillion River from Vermillion
to about 2: miles above LongCrcek. East Vennil~

.

lion Dam was built on the East Fork to provide
irrigation and recreation. but it has little flood
control capacity. Several smaller dams have
been built on the' forks and tributaries of the
Vermillion River, mw.tly to impound water
rather than to control flooding. In 1983 the
U.s. Soil Conservation Service finished a plan
{or i.mprovements in the Turkey and Clay

Creek watersheds in the lower part of the
Basin, but it was not implemented because
there was no lexal sponsorship. 1n 1987 the
Corps of Engineers began a 5+yea~ study of
Basin flooding, but no cost-effective solutions
\:hat met the Corps' criteria were found.
At the same time, the residents' concern
about other water-related is.~ucs has been grow'
i.ns. too. The U.$. Geological Survey and the
South Dakota Geological Survey examined the
quantity and quality of groundWOlter in Turner
County in J 990. Tht' Statewide Comprehensive
Outdoor Recreation Plan, completed in 1992,
outlined ways to handle growing pressure on
South Dakota's recreational resources. espe-
cially lakes. streams, and wetlands. The area is