Mississippi River IA 01-NEM-76
from Lock & Dam 10 at Guttenberg (Clayton Co.) to confluence with Wisconsin R across from McGregor Clayton Co.
Assessment Comments
008714 (1117MBR/US EPA) downstream of Guttenberg. Special study conducted by Wisconsin DNR in summer 1997.
Basis for Assessment
Used assessment of support of fish consumption uses developed for the 1996 report (=FS). Continue to assess overall support as FST due to known threats to water quality from nonpoint sources and exotic species. Also, used results of special study conducted by the Wisconsin DNR (Sullivan and Endris, January 1998) that showed low levels of dissolved oxygen (<3.0 mg/l) in the main channel of the Mississippi River during late June/early July 1997 during a period of high water temperatures and low river flow from Pool 9 downriver to Pool 12. Based on results of a study of the sediment oxygen demand in areas with and without zebra mussels, concluded that high densities of zebra mussels in the river were responsible for the low DO conditions; decomposition of phytoplankton is also believed to contribute to this problem.
Assessment Key Dates
Methods
| 260 | Fish tissue analysis |
Monitoring Levels
| Biological | 0 |
| Habitat | 0 |
| Physical Chemistry | 0 |
| Toxic | 0 |
| Pathogen Indicators | 0 |
| Other Health Indicators | 0 |
| Other Aquatic Life Indicators | 0 |
| # of Bio Sites | 0 |
| BioIntegrity | N/A |
| Causes | Use Support | Cause Magnitude | Sources | Source Magnitude |
|---|---|---|---|---|
| Organic enrichment/Low DO | Overall Use Support | Not Impairing |
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