Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Walnut Creek IA 04-RAC-1120

mouth (S13 T78 R25W Polk Co.) to Interstate 35/80 in S33 T79N R25W Polk Co.

Assessment Cycle
2002
Result Period
1998 - 2000
Designations
Assessment Methodology
Assessment Type
Monitored
Integrated Report
Category 0
Legacy ADBCode
IA 04-RAC-0020_1
Overall Use Support
Partial
Aquatic Life Use Support
Partial
Primary Contact Recreation
Not assessed
Documentation
Assessment Comments

Assessment is based on results of a DNR/UHL biocriteria sampling in 1998 (fish IBI= 48 (fair), BM-IBI= 53 (fair)).

Basis for Assessment

SUMMARY:  The Class A (primary contact recreation) uses remain "not assessed."  The Class B(LR) aquatic life uses remain assessed as "partially supported."  EXPLANATION:  The Class A uses remain "not assessed" due to lack of relevant water quality information upon which to base an assessment.   The aquatic life uses remain assessed as "partially supported" based on results of IDNR/UHL biological monitoring conducted on this stream segment in 1998 (see assessment for the 2000 report above).   These data are less than five years old and, according to IDNR's methodology for Section 305(b) assessments, are thus appropriate for characterizing current water quality conditions.

Monitoring and Methods
Assessment Key Dates
8/26/1998 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 Moderate
  • Bank or Shoreline Modification/Destabilization
  • Channelization
  • Habitat Modification (other than Hydromodification)
  • Hydromodification
  • Removal of Riparian Vegetation
  • Urban Runoff/Storm Sewers
  • Moderate
  • Moderate
  • Moderate
  • Moderate
  • Moderate
  • Moderate
Other habitat alterations Aquatic Life Support Moderate
  • Bank or Shoreline Modification/Destabilization
  • Channelization
  • Habitat Modification (other than Hydromodification)
  • Hydromodification
  • Removal of Riparian Vegetation
  • Urban Runoff/Storm Sewers
  • Moderate
  • Moderate
  • Moderate
  • Moderate
  • Moderate
  • Moderate