Iowa DNR
Iowa DNR
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Water Quality Assessments
Impaired Waters List

Middle Fork Grand River IA 05-GRA-1378

IA/MO line to trib S13T68NR30W Ringgold

Assessment Cycle
2006
Result Period
2002 - 2004
Designations
Class B(LR)
Assessment Methodology
Assessment Type
Monitored
Integrated Report
Category 5b
Legacy ADBCode
IA 05-GRA-0180_0
Overall Use Support
Not supporting
Aquatic Life Use Support
Not supporting
Documentation
Assessment Comments

Assessment based on 2004 REMAP data: FIBI = 18 (poor), BMIBI = 21 (poor). FIBI BIC = 33; BMIBI BIC = 41.

Basis for Assessment

The assessment was based on data collected in 2004 as part of the DNR/UHL stream REMAP 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 collected in the stream sampling reach.   The biological metrics were combined to make a fish community index of biotic integrity (FIBI) and a benthic macroinvertebrate index (BMIBI).   The indexes rank the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum).   The 2004 FIBI score was 18 (poor) and the BMIBI score was 21 (poor).   The aquatic life use support was assessed as not supporting (= NS), based on a comparison of the FIBI and BMIBI scores with biological impairment criteria (BIC) established for previous Section 305(b) reports.  The biological impairment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2004.   The FIBI BIC for this ecoregion is 33 and the BMIBI BIC for this ecoregion is 41.

Monitoring and Methods
Assessment Key Dates
7/14/2004 Biological Monitoring
Methods
220 Non-fixed station physical/chemical monitoring (conventional pollutant only)
315 Regional reference site approach
320 Benthic macroinvertebrate surveys
330 Fish surveys
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
Cause Unknown Aquatic Life Support Moderate
  • Source Unknown
  • Moderate
Cause Unknown Overall Use Support Moderate
  • Source Unknown
  • Moderate