Des Moines River IA 04-LDM-1012
from confluence with Cedar Cr. (S33 T75N R17W Mahaska Co.) to dam of Red Rock Reservoir in S19 T76N R18W Marion Co.
This is a Legacy Assessment. Prior to 2004, assessments were developed under a methodology that pre-dated the Integrated Report guidelines.
Assessment Cycle
1996
Result Period
1992 - 1994
Designations
Assessment Type
Monitored
Integrated Report
Category 0
Legacy ADBCode
IA 04-LDM-0020_3
Overall Use Support
Partial
Aquatic Life Use Support
Partial
Fish Consumption
Fully
Primary Contact Recreation
Fully
Documentation
Assessment Comments
Basis for Assessment
Had 1 viol in 14 samples for fecal coliform bacteria (=7% violation =FS). Only violations of Class B WQ criteria were copper (1 of 8 samples = 12% viol) and mercury (6 of 9 samples = 67 % viol). Sources of both metals are unknown and are probably naturally occurring. In addtion, despite rel large % of Hg violations, Hg levels in fish are <<FDA action level of 1.0 ppm. Problem with gas supersaturation remains as described in Lutz (1993) and Lutz (1995); thus, assess aquatic life use as PS; cause (100: unknown toxicity) and source (8800: upstream impoundment) from 1994 report remain valid.
Monitoring and Methods
Assessment Key Dates
Methods
| 420 | Water column surveys (e.g. fecal coliform) |
| 140 | Incidence of spills and/or fish kills |
| 230 | Fixed station physical/chemical (conventional plus toxic pollutants) |
| 260 | Fish tissue analysis |
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 |
|---|---|---|---|---|
| Unknown toxicity | Overall Use Support | High |
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| Unknown toxicity | Aquatic Life Support | High |
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