Upper Midwest Environmental Sciences Center
2001 Results in Pool 11 of the Upper Mississippi River
Sampling Efforts
Sampling began on June 25 and concluded July 25, 2001. Of the 568 sites targeted for sampling, 564 were sampled (Figure 5). Four sites were located too close to the lock and dam to be sampled safely.
Submersed Aquatic Vegetation
Submersed aquatic vegetation (SAV) was found at low frequencies poolwide compared to Pools 4, 8, and 13. The only exception was isolated backwaters where SAV was present in 73.3% of sampled sites (Table 4; Figure 6). The SAV was present in 26.2% of contiguous backwater sites and present between 9% and 12% in impounded, main channel border, and secondary channel areas. A total of 13 submersed aquatic species were found in Pool 11, with the highest species richness occurring in contiguous backwater and isolated areas.
Sago pondweed was the most abundant species poolwide (9.2%), followed by coontail (9.1%), and Eurasian watermilfoil (2.3%). Sago pondweed dominated most of the main channel border and impounded areas (7.7% and 9.8%, respectively), while coontail was most abundant in secondary channels and contiguous and isolated backwaters (7.8%, 20%, and 73.3%, respectively). The SAV was notably sparse in the lower pool (downstream from river mile 593), as 14% of sites were too deep to sample.
Rooted Floating-Leaf Vegetation
White waterlily, American lotus, and yellow pond-lily were the rooted floating-leaf species recorded in Pool 11. Rooted floating-leaf species were sparse poolwide, covering only 1.7% of sampled aquatic areas. Percent cover and frequency were highest in isolated backwaters (8% and 46.7%, respectively). Of the three species recorded, the American lotus and white waterlily were most abundant. Yellow pond-lily was found at only 0.2% of sites poolwide.
Content manager: Danelle Larson
Page Last Modified: April 17, 2018