Mississippi River IA 01-NEM-77
from Wisconsin R. near McGregor (Clayton Co.) to Lock & Dam 9 near Harpers Ferry Allamakee Co.
This is a Legacy Assessment. Prior to 2004, assessments were developed under a methodology that pre-dated the Integrated Report guidelines.
Assessment Cycle
1998
Result Period
1994 - 1996
Designations
Assessment Type
Monitored
Integrated Report
Category 0
Legacy ADBCode
IA 01-NEM-0040_1
Overall Use Support
Threatened
Aquatic Life Use Support
Threatened
Fish Consumption
Not assessed
Primary Contact Recreation
Not assessed
Documentation
Assessment Comments
Special WQ monitoring conducted by Wisconsin DNR.
Basis for Assessment
Used results of special study conducted by the Wisconsin DNR in summer 1997 that showed low levels of dissolved oxygen in the main channel of the Mississippi River from Pool 9 downriver to Pool 12. Based on densities of zebra mussels in the river, along with a study of sediment oxygen demand in areas with and without zebra mussels, study concluded that high densities of zebra mussels were likely the cause of the low DO. This study suggests an immediate threat to the water quality of the Upper Mississippi River.
Monitoring and Methods
Assessment Key Dates
| 8/1/1997 | Fixed Monitoring End Date |
| 6/1/1997 | Fixed Monitoring Start Date |
Methods
| 220 | Non-fixed station physical/chemical monitoring (conventional pollutant only) |
Monitoring Levels
| Biological | 0 |
| Habitat | 0 |
| Physical Chemistry | 4 |
| Toxic | 0 |
| Pathogen Indicators | 0 |
| Other Health Indicators | 0 |
| Other Aquatic Life Indicators | 0 |
| # of Bio Sites | 0 |
| BioIntegrity | N/A |
Causes and Sources of Impairment
| Causes | Use Support | Cause Magnitude | Sources | Source Magnitude |
|---|---|---|---|---|
| Organic enrichment/Low DO | Overall Use Support | Not Impairing |
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| Organic enrichment/Low DO | Aquatic Life Support | Not Impairing |
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