Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Silver Creek IA 01-WPS-363

from Crystal Cr. (aka Clear Cr.) (S23 T81N R3E Clinton Co.) to confluence with Negro Cr. in S27 T82N R3E Clinton Co.

Assessment Cycle
2002
Result Period
1998 - 2000
Designations
Assessment Methodology
Assessment Type
Monitored
Integrated Report
Category 0
Legacy ADBCode
IA 01-WPS-0070_2
Overall Use Support
Threatened
Aquatic Life Use Support
Threatened
Documentation
Assessment Comments

Assessment is based on results of (1) 1997 DNR Fisheries Bureau survey in DeWitt city park and (2) DNR 1998 Biocriteria sampling: Fish IBI= 40(fair), BM-IBI= 55(fairly good).

Basis for Assessment

SUMMARY:  The Class B(LR) aquatic life uses remain assessed as "fully supported / threatened" (minor impacts).   EXPLANATION:  The aquatic life uses remain assessed as "fully supported / threatened" based on results of the biological monitoring conducted on this stream segment in 1997 and 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
7/22/1998 Fixed Monitoring End Date
8/1/1997 Fixed Monitoring Start Date
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
Other habitat alterations Overall Use Support Not Impairing
  • Agriculture
  • Bank or Shoreline Modification/Destabilization
  • Channelization
  • Habitat Modification (other than Hydromodification)
  • Hydromodification
  • 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
  • Habitat Modification (other than Hydromodification)
  • Hydromodification
  • Not Impairing
  • Not Impairing
  • Not Impairing
  • Not Impairing
  • Not Impairing
Siltation Overall Use Support Not Impairing
  • Agriculture
  • Bank or Shoreline Modification/Destabilization
  • Channelization
  • Habitat Modification (other than Hydromodification)
  • Hydromodification
  • Not Impairing
  • Not Impairing
  • Not Impairing
  • Not Impairing
  • Not Impairing
Siltation Aquatic Life Support Not Impairing
  • Agriculture
  • Bank or Shoreline Modification/Destabilization
  • Channelization
  • Habitat Modification (other than Hydromodification)
  • Hydromodification
  • Not Impairing
  • Not Impairing
  • Not Impairing
  • Not Impairing
  • Not Impairing