Iowa DNR

Water Quality Assessments

Impaired Waters List

Floyd River IA 06-FLO-1552

mouth to West Branch Floyd R. in S2, T91N, R46W, Plymouth Co.

Assessment Cycle
Release Status
Result Period
1996 - 1998
Assessment Type
Integrated Report
Category 0
Legacy ADBCode
IA 06-FLO-0010_0
Overall Use Support
Aquatic Life Use Support
Fish Consumption
Not assessed
Assessment Comments

Assessment is based on results of IDNR ambient monthly water quality monitoring near James in 1998 & 1999.

Basis for Assessment

SUMMARY:  Assessed support of the Class B(WW) aquatic life uses as "fully supported."  Fish consumption remain "not assessed."  EXPLANATION:  The assessment of support of the Class B(WW) uses was based on results of water quality monitoring during the 1998-1999 biennial period at the DNR monthly monitoring station on the Floyd River near James (station 950110).   Results of this monitoring show no violations of Class B(WW) criteria for pH, dissolved oxygen, or ammonia nitrogen in the 23 samples analyzed during the biennial period; no violations of Class B(WW) chronic criteria for toxic metals occurred in the two samples analyzed during the biennial period.   Thus, the Class B(WW) aquatic life uses were assessed as "fully supported."  Although not designated for Class C (drinking water) uses, this river reach tends to have high levels of nitrate, with levels in 14 of the 23 samples collected during the biennial period exceeding the 10 mg/l MCL (mean=12.1 mg/l; max.=17.0 mg/l; SE=0.7).   Levels of total phosphorus were also relatively high, with a mean level of 0.48 mg/l (SE=0.03; N=23) for the 1998-1999 biennial period.   The results of the DNR stream use assessments conducted in September 1990-upon which previous assessments were partially based - are now considered too old (greater than five years) to be useful for assessing current water quality conditions.   Fish consumption uses were not assessed due to lack of fish tissue monitoring for this river reach.

Monitoring and Methods
Assessment Key Dates
230 Fixed station physical/chemical (conventional plus toxic pollutants)
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