Iowa DNR
Iowa DNR

ADBNet

Water Quality Assessments
Impaired Waters List

Keg Creek IA 06-WED-1686

mouth (S6 T71N R43W Mills Co.) to confluence with Little Keg Cr. in S27 T75N R42W Pottawattamie Co.

Assessment Cycle
2002
Result Period
1998 - 2000
Designations
Assessment Methodology
Assessment Type
Monitored
Integrated Report
Category 0
Legacy ADBCode
IA 06-WED-0010_1
Overall Use Support
Partial
Aquatic Life Use Support
Partial
Documentation
Assessment Comments

1997 Biocriteria: BM-IBI= 49(fair). 2001 Biocriteria: Fish IBI= 0(poor), BM-IBI= 63(good).

Basis for Assessment

The assessment was based on data collected in 1997 and 2001 as part of the DNR/UHL stream biocriteria project.   A series of biological metrics which reflect stream water quality and habitat integrity were calculated from the biocriteria sampling data.   The biological metrics are based on the numbers and types of benthic macroinvertebrate taxa and fish species that were collected in the stream sampling reach.   The biological metrics were combined to make a fish community index of biotic integrity (F-IBI) and a benthic macroinvertebrate index (BM-IBI).   The indexes rank the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum).   The 1997 and 2001 Fish IBI scores were 0 (poor) and 0 (poor); the 1997 and 2001 BM-IBI scores were 50 (fair) and 63 (good), respectively.  The aquatic life use support was assessed as partially supporting (=PS), based on a comparison of the F-IBI and BM-IBI scores with biological assessment criteria established specifically for the 2002 Section 305(b) report.  The biological assessment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2001.

Monitoring and Methods
Assessment Key Dates
8/2/2001 Fixed Monitoring End Date
8/2/2001 Biological Monitoring
7/30/1997 Fixed Monitoring Start Date
Methods
320 Benthic macroinvertebrate surveys
330 Fish surveys
220 Non-fixed station physical/chemical monitoring (conventional pollutant only)
315 Regional reference site approach
380 Quan. measurements of instream parms-- channel morphology-- floodplain-- 1-2 seasons-- by prof
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 Poor
Causes and Sources of Impairment
Causes Use Support Cause Magnitude Sources Source Magnitude
Other habitat alterations Overall Use Support Moderate
  • Channelization
  • Hydromodification
  • Moderate
  • Moderate
Other habitat alterations Aquatic Life Support Moderate
  • Channelization
  • Hydromodification
  • Moderate
  • Moderate
Siltation Overall Use Support Moderate
  • Channelization
  • Hydromodification
  • Moderate
  • Moderate
Siltation Aquatic Life Support Moderate
  • Channelization
  • Hydromodification
  • Moderate
  • Moderate