Iowa DNR

Water Quality Assessments

Impaired Waters List

Little Sioux River IA 06-LSR-1570

from Highway 3 (S26, T92N, R40W, Cherokee Co.) to confluence with Waterman Cr. in S26, T94N, R39W, O'Brien Co.

Assessment Cycle
Release Status
Result Period
1998 - 2000
Assessment Type
Integrated Report
Category 0
Legacy ADBCode
IA 06-LSR-0030_1
Overall Use Support
Aquatic Life Use Support
Fish Consumption
Not assessed
Primary Contact Recreation
Not assessed
Assessment Comments

Assessment is based on results of IDNR monthly ambient monitoring near Larrabee in 2000-2001.

Basis for Assessment

[Note:  For the 2002 report, the previous waterbody segment for the Little Sioux River (IA 06-LSR-0030-1), which extended 38 miles from the Highway 3 at Cherokee (Cherokee Co.) (approximately equal to confluence with Mill Creek north of Cherokee) to the Linn Grove Dam (Buena Vista Co.), was split into two subsegments:  (1) Highway 3 at Cherokee to confluence with Waterman Creek (O'Brien Co.) (IA 06-LSR-0030-1 - this one) and (2) Waterman Creek to the Linn Grove Dam (Buena Vista Co.) (IA 06-LSR-0030-2).   See previous Section 305(b) assessments from this subsegment for the original 38-mile river reach.]

For the 2002 report:  SUMMARY:  The Class B(WW) aquatic life uses are assessed as "fully supported."  Fish consumption uses remain "not assessed."  This assessment is based on results of IDNR monthly ambient monitoring conducted during the 2000-2001 biennial period near Larrabee (station 10180001 (formerly station 911060)).   EXPLANATION:  Monitoring at the IDNR station near Larrabee showed no violations of Class B(WW) water quality criteria during the 2000-2001 biennial period for dissolved oxygen (minimum value = 6.7 mg/l), pH (range = 7.7 to 8.9 units), or ammonia-nitrogen (maximum value = 0.40 mg/l) in the 24 samples analyzed.   In addition, levels of toxic metals in the four samples analyzed, and levels of pesticides in the six samples analyzed, were all below the analytical level of detection.   These results suggest "full support" of the Class B(WW) aquatic life uses.   Fish consumption uses remain "not assessed due to the lack of recent fish contaminant monitoring in this river reach.

Monitoring and Methods
Assessment Key Dates
9/6/2001 Fixed Monitoring End Date
10/6/1999 Fixed Monitoring Start Date
230 Fixed station physical/chemical (conventional plus toxic pollutants)
Monitoring Levels
Biological 0
Habitat 0
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