Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Beaver Creek IA 04-UDM-1235

from confluence with Slough Cr. to confluence with unnamed tributary in S29 T84N R28W Boone Co.

Assessment Cycle
2008
Result Period
2004 - 2006
Designations
Class A1 Class B(WW-2)
Assessment Methodology
Assessment Type
Evaluated
Integrated Report
Category 2a
Legacy ADBCode
IA 04-UDM-0120_0
Overall Use Support
Fully
Aquatic Life Use Support
Fully
Primary Contact Recreation
Not assessed
Documentation
Assessment Comments

Assessment is based on results of IDNR/UHL biological (biocriteria) monitoring in 2001: FIBI = 38 (fair), BMIBI = 65 (good). 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 Class B(WW2) aquatic life uses are assessed (evaluated) as "fully supported"  based on results of IDNR/UHL biological (biocriteria) sampling in 2001.   The 2001 sampling data are now more than five years old; therefore, this assessment is now considered "evaluated" instead of "monitored".  

EXPLANATION:  The assessment of the Class B(WW2) aquatic life uses was based on data collected in 2001 as part of the IDNR/UHL stream biocriteria project.   The 2001 FIBI score was 38 (fair) and the BMIBI score was 65 (good).   The aquatic life use support was assessed as Fully Supported (=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 habitat FIBI BIC for this ecoregion is 32 and the BMIBI BIC for this ecoregion is 62.

Monitoring and Methods
Assessment Key Dates
7/25/2001 Biological Monitoring
7/25/2001 One-time Chemical 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
150 Monitoring data more than 5 years old
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
Siltation Aquatic Life Support Not Impairing
  • Agriculture
  • Bank or Shoreline Modification/Destabilization
  • Channelization
  • Grazing related Sources
  • Habitat Modification (other than Hydromodification)
  • Pasture grazing - Riparian
  • 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