1998 vegetation in Pools 4, 8, 13, and 26 and La Grange Pool of the UMRS

Yin, Y., H. Langrehr, T. Blackburn, M. Moore, J. Winkelman, R. Cosgriff, and T.
Cook. 2001. 1998 annual status report: Submersed and rooted floating leaf vegetation
in Pools 4, 8, 13, and 26 and La Grange Pool of the Upper Mississippi River System.
U.S. Geological Survey, Upper Midwest Environmental Sciences Center, La Crosse,
Wisconsin, May 2001. LTRMP 2001-P001. 9 pp. + Appendix + Chapters 1 5

ABSTRACT

Aquatic vegetation was investigated in five navigation pools in the Upper Mississippi
River System using a new protocol named "stratified random sampling" or SRS protocol
for the first time in 1998. The five pools were Pools 4, 8, 13, and 26 of the Upper
Mississippi River and La Grange Pool of the Illinois River. The results on submersed
aquatic vegetation and rooted floating leaf aquatic vegetation were summarized in this
report. The percent frequencies of submersed aquatic vegetation in shallow water areas
(œ 3 m deep at flat-pool condition) in the five pools were 36.6%, 47.6%, 42%, 6.1%, and
0%, respectively. The aquatic area strata that were directly influenced by the flow in the
main channel, such as the main channel borders and secondary channels, had lower
percent frequencies of submersed aquatic vegetation than the aquatic area strata that were
less directly influenced by the flow in the main channel, such as the contiguous and
isolated backwaters. The percent covers of rooted floating leaf vegetation were 4.1%,
7.5%, 6.5%, 0.9%, and 0%. The majority of aquatic vegetation that was recorded in Pool
26 was from one isolated backwater area. Aquatic vegetation was not recorded at any of
the sampling sites in La Grange Pool.

KEYWORDS

Annual report, aquatic, floating leaf, Illinois River, La Grange, LTRMP, Mississippi
River, submersed vegetation