Iowa DNR

Water Quality Assessments

Impaired Waters List

Beaver Creek IA 02-CED-555

mouth (S34, T90N, R14W, Black Hawk Co.) to confluence with South Beaver Cr. in S25, T90R, R17W, Butler Co.

Assessment Cycle
Release Status
Result Period
1996 - 1998
Assessment Type
Integrated Report
Category 0
Legacy ADBCode
IA 02-CED-0400_0
Overall Use Support
Aquatic Life Use Support
Fish Consumption
Not assessed
Assessment Comments

Stream use assessment in 1992.

Basis for Assessment

SUMMARY:  Assessed support of the Class B(WW) aquatic life uses as "fully supported / threatened."  Fish consumption uses remaind "not assessed."  EXPLANATION:  The previous assessment of support of the Class B(WW) uses ("fully supported / threatened"; see assessment for the 1998 report above) was based primarily on the results of a DNR stream use assessment in July 1992.   The results of this stream assessments, however, are greater than five years old and are thus considered too old to be useful for assessing current water quality conditions.   Results of DNR quarterly water quality monitoring from the station located approximately 3.5 miles NNW of Cedar Falls during the 1998-1999 biennial period showed no violations of water quality criteria to protect the Class B(WW) aquatic life uses:  no violations of state water quality criteria conventional or toxic parameters (dissolved oxygen, pH, and ammonia-nitrogen) occurred in the 8 samples collected during this monitoring period; neither of the two samples analyzed for toxic metals showed violations of these criteria.   As noted in the previous (1998) assessment, however, this portion of Beaver Creek has threats to full support of aquatic life uses.   Although water quality conditions appear to fully support the designated aquatic life uses, follow-up biological monitoring is needed to determine the status of the aquatic communities and habitats and to better determine the degree to which the Class B(WW) uses are supported.   This assessment was based on results of quarterly monitoring.   Results from stations monitored monthly or more frequently, however, are preferred for Section 305(b) assessments in order to improve the accuracy and confidence level of the assessement.   As part of DNR's expanded water quality monitoring program, monthly monitoring at the Cedar Falls station began in October 1999.

Monitoring and Methods
Assessment Key Dates
7/1/1992 DNR Stream Use Assessment
330 Fish surveys
375 Visual observation-- may not quantify some parameters-- single season-- by prof.
150 Monitoring data more than 5 years old
Monitoring Levels
Biological 3
Habitat 3
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