Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

North Skunk River IA 03-NSK-858

from confluence with Middle Cr. (S35 T76N R14W Mahaska Co.) to the Mahaska/Poweshiek county line.

Assessment Cycle
1998
Result Period
1994 - 1996
Designations
Assessment Type
Monitored
Integrated Report
Category 0
Legacy ADBCode
IA 03-NSK-0020_1
Overall Use Support
Threatened
Aquatic Life Use Support
Threatened
Documentation
Assessment Comments

Assessment is based on 1996 biocriteria sampling: fish, 22 spp., 4 fams.; Fish IBI= 36(fair), BM-IBI= 53(fair).

Basis for Assessment

Used results of the DNR biocriteria sampling in October 1996 to assess support of the Class B(LR) aquatic life uses as FST due to (1) presence of a relatively diverse fish community of 22 species from 4 families, (2) presence a majority of the expected fish taxa (6 of 8) for streams in the portion of the Southern Iowa Rolling Loess Prairies subecoregion that drains to the Mississippi River, and (3) lack of violations of Class B(LR) WQ criteria in the sample collected during biocriteria sampling.   Missing fish taxa were stream-dwelling centrarchids and darter spp.

Monitoring and Methods
Assessment Key Dates
10/7/1996 Biological Monitoring
Methods
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
320 Benthic macroinvertebrate surveys
Monitoring Levels
Biological 4
Habitat 4
Physical Chemistry 1
Toxic 0
Pathogen Indicators 0
Other Health Indicators 0
Other Aquatic Life Indicators 0
# of Bio Sites 1
BioIntegrity Fair
Causes and Sources of Impairment
Causes Use Support Cause Magnitude Sources Source Magnitude
Other habitat alterations Overall Use Support Not Impairing
  • Agriculture
  • Bank or Shoreline Modification/Destabilization
  • Channelization
  • Habitat Modification (other than Hydromodification)
  • Hydromodification
  • Not Impairing
  • Not Impairing
  • Not Impairing
  • Not Impairing
  • Not Impairing
Other habitat alterations Aquatic Life Support Not Impairing
  • Agriculture
  • Bank or Shoreline Modification/Destabilization
  • Channelization
  • Habitat Modification (other than Hydromodification)
  • Hydromodification
  • Not Impairing
  • Not Impairing
  • Not Impairing
  • Not Impairing
  • Not Impairing