Iowa DNR

Water Quality Assessments

Impaired Waters List

Indian Creek IA 03-SSK-943

mouth (S32 T80N R20W Jasper Co.) to confluence of East Indian and West Indian creeks in S16 T82N R22W Story Co.

Assessment Cycle
Result Period
1998 - 2000
Assessment Methodology
Assessment Type
Integrated Report
Category 0
Legacy ADBCode
IA 03-SSK-0040_0
Overall Use Support
Aquatic Life Use Support
Assessment Comments

Assessment is based on results of IDNR ambient monthly monitoring near Colfax in 2000 & 2001.

Basis for Assessment

SUMMARY:  The Class B(LR) aquatic life uses are assessed as fully supported."  The source of data for this assessment is the results of IDNR monthly ambient monitoring conducted in 2000 and 2001 on Indian Creek at a bridge 4.8 miles north of Colfax and 1.8 miles east of Green Castle in Jasper County (station 10500001).   EXPLANATION:  Results of monitoring at the IDNR station show no violations of Class B(WW) criteria for pH or ammonia nitrogen (maximum value = 0.40 mg/l) in the 24 samples analyzed during the 2000-2001 biennial period and no violations of Class B(LR) chronic criteria for toxic metals in the four samples analyzed, or for pesticides and other toxic organic compounds in the six samples analyzed, during the biennial period.   One sample, however, contained a level of dissolved oxygen that violated the Class B(LR) water quality criterion.   The sample collected on December 20, 2000, contained 4.9 mg/l of dissolved oxygen, thus slightly violating the Class B(LR) criterion of 5.0 mg/l.   According to U.S.  EPA guidelines for Section 305(b) reporting (U.S.  EPA 1997b:  page 3-17), however, a violation frequency for conventional parameters (including dissolved oxygen) of 10% or less does not suggest an impairment of aquatic life uses.   Thus, the Class B(LR) aquatic life uses were assessed as "fully supported."

Monitoring and Methods
Assessment Key Dates
9/17/2001 Fixed Monitoring End Date
10/18/1999 Fixed Monitoring Start Date
230 Fixed station physical/chemical (conventional plus toxic pollutants)
Monitoring Levels
Biological 0
Habitat 0
Physical Chemistry 0
Toxic 0
Pathogen Indicators 0
Other Health Indicators 0
Other Aquatic Life Indicators 0
# of Bio Sites 0
BioIntegrity N/A