Iowa DNR

Water Quality Assessments

Impaired Waters List

West Nishnabotna River IA 05-NSH-1441

from confluence with Silver Cr. (S21, T71N, R41W, Mills Co.) to confluence Farm Cr. in S9, T73N, R40W, Mills Co.

Assessment Cycle
Release Status
Result Period
2002 - 2004
Class B(WW)
Assessment Type
Integrated Report
Category 2a
Legacy ADBCode
IA 05-NSH-0080_1
Overall Use Support
Aquatic Life Use Support
Fish Consumption
Not assessed
Assessment Comments

Assessment is based on results of IDNR/UHL ambient monthly water quality monitoring near Malvern from 2002-04.

Basis for Assessment

SUMMARY:  The Class B(WW) aquatic life uses are assessed (monitored) as "fully supported" based on results of ambient chemical/physical water quality monitoring from 2002 through 2004.   Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this river segment.   This assessment is based on results of IDNR/UHL monthly ambient water quality monitoring conducted during the 2002-2004 assessment period east of Malvern (STORET station 10650001 (formerly station 822310)).  

EXPLANATION:  Monitoring at the IDNR/UHL station near Malvern showed no violations of Class B(WW) water quality criteria during the 2002-2004 assessment period for dissolved oxygen, pH, and ammonia-nitrogen in the 36 samples analyzed.  In addition, levels of pesticides in the seven samples analyzed, and levels of toxic metals in the ten samples analyzed, were all below the respective Class B(WW) criteria.   These results suggest "full support" of the Class B(WW) aquatic life uses.  

Fish consumption uses remain "not assessed" due to the lack of fish tissue monitoring in this river segment.

Monitoring and Methods
Assessment Key Dates
12/6/2004 Fixed Monitoring End Date
1/7/2002 Fixed Monitoring Start Date
230 Fixed station physical/chemical (conventional plus toxic pollutants)
Monitoring Levels
Biological 0
Habitat 0
Physical Chemistry 3
Toxic 3
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