Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Dry Run IA 02-CED-554

mouth (S18 T89N R13W Black Hawk Co.) to confluence with unnamed tributary in S23 T89N R14W BlackHawk Co

Assessment Cycle
2004
Result Period
2000 - 2002
Designations
Assessment Methodology
Assessment Type
Monitored
Integrated Report
Category 5b
Legacy ADBCode
IA 02-CED-0390_0
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) sampling in 1999: Fish IBI= 50(fair), BM-IBI= 48(fair).

Basis for Assessment

SUMMARY:  The Class A (primary contact recreation) uses are "not assessed" due to the lack of information upon which to base an assessment.  The Class B(LR) aquatic life uses are assessed (monitored) as "partially supported"  based on results of IDNR/UHL biological (biocriteria) sampling in 1999.   This is the same assessment as that developed for the 2002 reporting cycle.

EXPLANATION:  The Class A uses are "not assessed" due to the lack of monitoring information upon which to base an assessment.

The assessment of the Class B(LR) aquatic life uses was based on data collected in 1999 as part of the DNR/UHL stream biocriteria 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 (F-IBI) and a benthic macroinvertebrate index (BM-IBI).   The indexes rank the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum).   The 1999 Fish IBI score was 50 (fair) and the BM-IBI score was 48 (fair).  The aquatic life use support was assessed as partially supporting (=PS), based on a comparison of the F-IBI and BM-IBI scores with biological assessment criteria established specifically for the 2002 Section 305(b) report.  The biological assessment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2001.

Monitoring and Methods
Assessment Key Dates
10/6/1999 Biological Monitoring
10/6/1999 One-time Chemical Monitoring
Methods
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 0
BioIntegrity N/A
Causes and Sources of Impairment
Causes Use Support Cause Magnitude Sources Source Magnitude
Cause Unknown Aquatic Life Support Moderate
  • Industrial Point Sources
  • Source Unknown
  • Urban Runoff/Storm Sewers
  • Moderate
  • Moderate
  • Moderate