Iowa DNR

Water Quality Assessments

Impaired Waters List

Maple River IA 06-LSR-1581

mouth (S17, T83N, R44W, Monona Co.) to confluence with unnamed tributary approximately 1 mile east of Danbury in SW 1/4, NE 1/4, S26, T86N, R42W, Woodbury Co.

Assessment Cycle
Release Status
Result Period
1996 - 1998
Assessment Type
Integrated Report
Category 0
Legacy ADBCode
IA 06-LSR-0070_1
Overall Use Support
Aquatic Life Use Support
Fish Consumption
Not assessed
Assessment Comments

The assessment is based on results from the August 1997 DNR/UHL biocriteria sampling near Ida Grove (Fish IBI=39, BM IBI=70) and on the results from an IDNR stream use assessment conducted in October 1995 near Ida Grove.

Basis for Assessment

SUMMARY:  The Class B(WW) aquatic life uses are considered "fully supported / threatened."  Fish consumption uses remain "not assessed."  EXPLANATION:  The assessment of support of the Class B(WW) uses developed for previous reports (see above) was based, in part, on results of DNR quarterly water quality monitoring near Mapleton (station 911040).   Data from this station, however, were last collected from October 1991 through September 1993 and are thus considered too old (greater than five years) for characterizing current water quality conditions.   As part of DNR's expanded water quality monitoring program, monthly monitoring at the Mapleton station began in October 1999.   Results from this monitoring will allow development of an updated assessment of support of beneficial uses for the 2002 report.   The current assessment is based primarily on results from the August 1997 DNR/UHL biocriteria sampling near Ida Grove.   Based on a comparison to results of ecoregion reference site sampling, the fish community was rated "fair) (Fish IBI=39), and the benthic macroinvertebrate community was rated "good" (BM IBI=70).   These results suggest that the aquatic life uses are "fully supported / threatened."  This assessment is also based on results from a DNR stream use assessment conducted in October 1995 near Ida Grove (see assessment for the 1998 report above).   Results of this stream use assessment also suggest that the Class B(WW) aquatic life uses are "fully supported / threatened."  Fish consumption uses remained "not assessed" due to the lack of recent fish tissue monitoring in this river reach.

Monitoring and Methods
Assessment Key Dates
330 Fish surveys
380 Quan. measurements of instream parms-- channel morphology-- floodplain-- 1-2 seasons-- by prof
315 Regional reference site approach
320 Benthic macroinvertebrate surveys
220 Non-fixed station physical/chemical monitoring (conventional pollutant only)
Monitoring Levels
Biological 3
Habitat 3
Physical Chemistry 3
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