Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Iowa Lake IA 06-LSR-1602

Osceola County S9T100NR39W 4 mi NNW of Harris.

Cycle
2024
Release Status
Final
Overall IR
3 - Insufficient data exist to determine whether any designated uses are met.
Trophic
Hypereutrophic
Trend
Unknown
Created
11/14/2023 3:28:41 PM
Updated
2/5/2024 9:31:52 AM
Use Support
Class BLW
Aquatic Life - Lakes and wetlands
WINOFI
Impairment Code
3b - Use potentially impaired based on an evaluated assessment.
Cause Magnitude
Moderate
Status
New
Source
Multiple Sources
Source Confidence
Low
Cycle Added
2024
Impairment Rationale
Potential Impairment
Data Source
Biological monitoring: Iowa DNR Fisheries
Impairment Code
3b - Use potentially impaired based on an evaluated assessment.
Cause Magnitude
Moderate
Status
New
Source
Agriculture
Source Confidence
Low
Cycle Added
2024
Impairment Rationale
Potential Impairment
Data Source
Ambient monitoring: Iowa DNR-shallow lakes & wetlands
Class HH
Human Health -
Not Assessed
Impairment Delistings
No delistings for this assessment cycle.
Documentation
Assessment Summary

The Class BLW use was assessed (evaluated) as "WINOFI" based on information from the DNR Water Quality Bureau and Fisheries Bureau. All other designated uses were “not assessed.”

Assessment Explanation

Class BLW -

The Class BLW aquatic life use was assessed (evaluated) as "WINOFI" based on information from the Iowa DNR Fisheries Bureau. According to local DNR fisheries Biologist, this lake has excessive turbidity and little to no aquatic plant life. Turbidity issues likely due to excessive nutrients and/or high densities of common carp. Additionally,accordingto Water Quality Bureau Monitoring Staff, this system suffers from high turbidity and significantalgal blooms. The assessment category for this wetland of "evaluated" indicates that the assessment is based entirely on "best professional judgment." In terms of Section 305(b) reporting, "monitored assessments" are based primarily on recent, site-specific ambient monitoring data and thus have relatively high confidence. DNR considers waterbodies identified as "impaired" based on "monitored assessments" as candidates for the state's Section 303(d) list. "Evaluated assessments" are those based on data older than five years or other than site-specific ambient monitoring data (e.g., questionnaire surveys of fish and game biologists [=best professional judgment]) and thus have relatively lower confidence. DNR does not consider waterbodies identified as "impaired" based on "evaluated assessments" as candidates for the state's Section 303(d) list.

Class HH - Fish Tissue sampling: No Data

In general, Iowa wetlands are not managed for recreational fisheries; thus, fish contaminant monitoring is not typically conducted at these waterbodies.

Monitoring and Methods
Assessment Key Dates

None listed

Methods
120
Surveys of fish and game biologists/other professionals