Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Winnebago River IA 02-WIN-831

from confluence with Pike Run (S25 T99N R24W Winnebago Co.) to the Iowa/Minnesota state line

Assessment Cycle
2008
Result Period
2004 - 2006
Designations
Class A1 Class B(WW-2)
Assessment Methodology
Assessment Type
Monitored
Integrated Report
Category 5b
Legacy ADBCode
IA 02-WIN-0020_2
Overall Use Support
Partial
Aquatic Life Use Support
Partial
Primary Contact Recreation
Not assessed
Documentation
Assessment Comments

Assessment is based on results of IDNR/UHL biological (biocriteria) monitoring in 2006: FIBI = 32 (fair); BMIBI = 46 (fair). Non-riffle habitat FIBI BIC = 32, BMIBI BIC = 62.

Basis for Assessment

[Note:  Prior to the current (2008) Section 305(b) cycle, this stream segment was designated only for Class B(LR) aquatic life uses.   Due to changes in Iowa’s surface water classification that were approved by U.S.  EPA in February 2008 (see http://www.iowadnr.com/water/standards/files/06mar_swc.pdf), this segment is now presumptively designated for Class A1 (primary contact recreation) uses.   The stream remains designated for aquatic life uses (now termed Class B(WW2) aquatic life uses).   Thus, for the current (2008) assessment, the available water quality monitoring data will be compared to the applicable Class A1 and Class B(WW2) water quality criteria.]

SUMMARY:  The presumptive Class A1 (primary contact recreation) uses are "not assessed" due to the lack of information upon which to base an assessment.   The aquatic life uses are assessed (monitored) as "partially supported"  based on results of IDNR/UHL biological (biocriteria) sampling in 2006.

EXPLANATION:  The assessment of the Class B(WW2) aquatic life uses was based on data collected in 2006 as part of the IDNR/UHL stream biocriteria project.  The 2006 FIBI score was 32 (fair) and the BMIBI score was 46 (fair).   The aquatic life use support assessment was assessed as Partially Supporting (=PS), 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 habitat FIBI BIC for this ecoregion is 32 and the BMIBI BIC for this ecoregion is 62.

Monitoring and Methods
Assessment Key Dates
9/19/2006 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 Fair
Causes and Sources of Impairment
Causes Use Support Cause Magnitude Sources Source Magnitude
Cause Unknown Aquatic Life Support Slight
  • Source Unknown
  • Slight
Other habitat alterations Aquatic Life Support Not Impairing
  • Bank or Shoreline Modification/Destabilization
  • Habitat Modification (other than Hydromodification)
  • Not Impairing
  • Not Impairing