West Nishnabotna River IA 05-NSH-1445
from confluence with West Fork West Nishnabotna R. (NW 1/4 S18 T79N R39W Shelby Co) to confluence with Elk Cr. in S36 T81N R38W Shelby Co.
Assessment Comments
Assessment is based on results of 1994 Biocriteria sampling.
Basis for Assessment
Changed the assessment of support of the Class B(LR) aquatic life uses from PS to FST due to results of the August 1994 DNR biocriteria sampling that showed this reach of the W. Nishnabotna to support a fish community typical of the Class B(LR) streams in this region (9 spp; 4 fams were captured). Thus, despite the considerable habitat alterations in this reach, the composition of the fish community strongly suggests that the Class B(LR) water quality standards are fully supported (5 of the 7 fish taxa expected in streams of the Loess Hills and Rolling Prairies (47e) subecoregion were captured during the biocriteria sampling, thus suggesting that the Class B(LR) uses are FST). The number of fish per species, however, was unusually low (approximately 10). Follow-up monitoring is needed to determine the status of the aquatic communities and to determine whether the Class B(LR) uses may be impaired.
Assessment Key Dates
| 8/9/1994 | Biological Monitoring |
Methods
| 320 | Benthic macroinvertebrate surveys |
| 330 | Fish surveys |
| 380 | Quan. measurements of instream parms-- channel morphology-- floodplain-- 1-2 seasons-- by prof |
| 220 | Non-fixed station physical/chemical monitoring (conventional pollutant only) |
| 315 | Regional reference site approach |
Monitoring Levels
| Biological | 3 |
| Habitat | 3 |
| Physical Chemistry | 1 |
| Toxic | 0 |
| Pathogen Indicators | 0 |
| Other Health Indicators | 0 |
| Other Aquatic Life Indicators | 0 |
| # of Bio Sites | 1 |
| BioIntegrity | Fair |