Iowa DNR

Water Quality Assessments

Impaired Waters List

Ioway Creek IA 03-SSK-954

mouth (S12 T83N R24W Story Co.) to confluence with unnamed tributary in NW 1/4 S9 T85N R25W Boone Co.

Assessment Cycle
Result Period
2002 - 2004
Class B(LR)
Assessment Methodology
Assessment Type
Integrated Report
Category 1
Legacy ADBCode
IA 03-SSK-0060_0
Overall Use Support
Aquatic Life Use Support
Assessment Comments

Assessment based on 2002 REMAP data: FIBI = 45 (fair), BMIBI = 80 (excellent) and on 2000 biocriteria data: FIBI = 51 (good), 43 (fair), 41 (fair); BMIBI = 74 (good), 74 (good). FIBI ave = 45, BMIBI ave = 76. Non-riffle FIBI BIC = 32, BMIBI BIC = 62.

Basis for Assessment

SUMMARY:  The Class B(LR) aquatic life uses are assessed (monitored) as "fully supported" based on results of (1) IDNR/UHL biological (biocriteria) sampling in 2000 and (2) IDNR/UHL biological (REMAP) sampling in 2002.  

EXPLANATION:  The assessment was based on data collected in 2000 as part of the DNR/UHL stream biocriteria project and in 2002 as part of the DNR/UHL 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 that were 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 2000 FIBI scores were 51 (good), 43 (fair), 41 (fair) and the BMIBI scores were 74, 74 (good).   The 2002 FIBI score was 45 (fair) and the BMIBI score was 80 (excellent).   The FIBI average was 45 and the BMIBI average was 76.   The aquatic life use support was assessed as fully supporting (= FS), 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 non-riffle FIBI BIC for this ecoregion is 32 and the BMIBI BIC for this ecoregion is 62.

Monitoring and Methods
Assessment Key Dates
7/18/2002 Biological Monitoring
7/18/2002 One-time Chemical Monitoring
7/14/2000 Biological Monitoring
7/14/2000 One-time Chemical Monitoring
7/13/2000 Biological Monitoring
7/12/2000 Biological Monitoring
7/12/2000 One-time Chemical Monitoring
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 4
Habitat 4
Physical Chemistry 1
Toxic 0
Pathogen Indicators 0
Other Health Indicators 0
Other Aquatic Life Indicators 0
# of Bio Sites 4
BioIntegrity Good