Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Little Maple River IA 06-LSR-1596

mouth (SW 1/4 S34 T90N R39W Ida Co.) to confluence with unnamed tributary in NE 1/4 S20 T90N R38W Buena Vista Co.

Assessment Cycle
2000
Result Period
1996 - 1998
Designations
Assessment Methodology
Assessment Type
Monitored
Integrated Report
Category 0
Legacy ADBCode
IA 06-LSR-0110_0
Overall Use Support
Threatened
Aquatic Life Use Support
Threatened
Documentation
Assessment Comments

Assessment is based on results of 1997 Biocriteria sampling: Fish IBI=39 (fair), BM-IBI=69 (good).

Basis for Assessment

The assessment was based on data collected in 1997 for the Maple River watershed bioassessment project conducted 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 F-IBI score was 39 (fair), and the BM-IBI score was 69 (good).   The aquatic life use support was assessed as fully supported / threatened (=FST), based on a comparison of the F-IBI and BM-IBI scores with biological assessment criteria established specifically for the 2000 Section 305(b) report.   The biological assessment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-1998.

Monitoring and Methods
Assessment Key Dates
8/20/1997 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
  • Grazing related Sources
  • Habitat Modification (other than Hydromodification)
  • Hydromodification
  • Pasture grazing - Riparian
  • Not Impairing
  • Not Impairing
  • 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
  • Grazing related Sources
  • Habitat Modification (other than Hydromodification)
  • Hydromodification
  • Pasture grazing - Riparian
  • Not Impairing
  • Not Impairing
  • Not Impairing
  • Not Impairing
  • Not Impairing
  • Not Impairing
  • Not Impairing