Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Brown Creek IA 04-UDM-1305

mouth (NW 1/4 S24 T99N R34W Emmet Co.) to IA/MN state line.

Assessment Cycle
2002
Result Period
1998 - 2000
Designations
Assessment Methodology
Assessment Type
Evaluated
Integrated Report
Category 0
Legacy ADBCode
IA 04-UDM-0400_0
Overall Use Support
Partial
Aquatic Life Use Support
Partial
Documentation
Assessment Comments

Assessment is based on occurrence of a fish kill in September 1998.

Basis for Assessment

SUMMARY:  The general aquatic life uses remain assessed (evaluated) as "partially supported" due to occurrence of a fish kill.   EXPLANATION:  The previous (2000) assessment of the aquatic life uses was based on the occurrence of a fish kill in 1998 (see assessment for the 2000 report above).   According to IDNR's assessment methodology for Section 305(b) reporting, occurrence of a single pollution-caused fish kill within the most recent three-year period indicates ongoing impairment of the aquatic life uses.   The absence of a fish kill in the three-year period following a fish kill suggest that impacts from the kill have likely dissipated.   Because the most recent pollution-caused fish kill occurred on this stream segment prior to the most recent three-year period (1999, 2000, 2001), but occurred no more than six years ago, the aquatic life uses remain assessed as "partially supported."  Due to the age of the kill (more than three years old), however, the confidence level for this assessment should be considered relatively low.

Monitoring and Methods
Assessment Key Dates
8/27/1998 Fishkill
Methods
140 Incidence of spills and/or fish kills
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
Causes and Sources of Impairment
Causes Use Support Cause Magnitude Sources Source Magnitude
Organic enrichment/Low DO Overall Use Support Moderate
  • Agriculture
  • Intensive Animal Feeding Operations
  • Moderate
  • Moderate
Organic enrichment/Low DO Aquatic Life Support Moderate
  • Agriculture
  • Intensive Animal Feeding Operations
  • Moderate
  • Moderate
Unionized Ammonia Overall Use Support Moderate
  • Agriculture
  • Intensive Animal Feeding Operations
  • Moderate
  • Moderate
Unionized Ammonia Aquatic Life Support Moderate
  • Agriculture
  • Intensive Animal Feeding Operations
  • Moderate
  • Moderate