Recreational boating impact investigations - Upper Mississippi River System, Pool 4, Red Wing, Minnesota

Field investigations were undertaken to document physical and
water quality impacts associated with recreational boating
activities in upper Pool 4 of the Upper Mississippi River System. 
The study documented high erosion rates irrespective of geomorphic
position in the Main Channel and development of a diurnal
turbidity plume in the littoral zone.  A comparison of commercial
tow, wind, and recreational boat surface wave characteristics,
along with other observations and the use of a control channel
provided the perspective necessary to determine relative
responsibility for the observed impacts.  Recreational boating was
found to be the contributing influence most responsible for the
high shoreline erosion rates documented along the Main Channel and
was found to be directly responsible for the development of the
diurnal turbidity plume in the Main Channel's littoral zone on
weekends and holidays.  Other applicable literature findings were
reviewed and potential impacts to the river habitat and biota
associated with recreational boating activity were identified. 
Federal, State, and local government agencies responsible for
managing the Upper Mississippi River System should respond to the
findings of this report by implementing programs to protect the
river from recreational boating impacts.