Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

High Lake IA 04-UDM-1304

Emmet County S14T98NR33W 4 mi. ESE of Wallingford.

Cycle
2022
Release Status
Final
Overall IR
5 - Water is impaired or threatened and a TMDL is needed.
Trend
Stable
Created
12/30/2021 11:02:53 AM
Updated
2/17/2022 2:48:55 PM
Use Support
Class A1
Recreation - Primary contact
Fully Supported
Class BLW
Aquatic Life - Lakes and wetlands
Not Supported
Support Level
Not Supported
Impairment Code
5a - Pollutant-caused impairment. TMDL needed.
Cause Magnitude
Moderate
Status
Continuing
Source
Agriculture
Source Confidence
Moderate
Cycle Added
2014
Impairment Rationale
Adverse impacts on plant/animal communities
Data Source
Ambient monitoring: Iowa DNR-shallow lakes & wetlands
TMDL Priority
Tier IV
Support Level
Not Supported
Impairment Code
5a - Pollutant-caused impairment. TMDL needed.
Cause Magnitude
Moderate
Status
Continuing
Source
Agriculture
Source Confidence
Moderate
Cycle Added
2014
Impairment Rationale
Adverse impacts on plant/animal communities
Data Source
Ambient monitoring: Iowa DNR-shallow lakes & wetlands
TMDL Priority
Tier IV
Class HH
Human Health -
Not Assessed
Impairment Delistings
No delistings for this assessment cycle.
Documentation
Assessment Summary

The Class A1 use was assessed (monitored) as "fully supported." The Class BLW use was assessed (monitored) as "not supported" (IR 5a) due to high levels of total suspended solids that leads to an impairment of the narrative criteria protecting against undesirable or nuisance aquatic life. High levels of algae at this wetland also suggest impairment due to aesthetically objectionable conditions. All other designated uses were “not assessed.”

Assessment Explanation

  • Data Sources:

    Data Source

    Data Source ID

    Data Type

    Data Age

    Site ID

    Site Name

    Site Description

    Iowa DNR

    6

    WQ

    CY 2017-2020

    22320003

    High Lake

    Class A1 - Indicator Bacteria: No Data

    Class A1 - pH

    Site ID

    Data Source ID

    # Samples / # Years

    Minimum Value

    Maximum Value

    Mean Value

    # Violations

    Violations needed for impairment

    Violates Significantly >10% Rule?

    Assessment Type

    Support Level

    22320003

    6

    20 / 4

    7.13

    10.98

    8.6

    2

    5

    NO

    Monitored

    Full

    Class BLW - Lake TSI's

    Site ID

    Data Source ID

    Parameter Name

    # Samples / # Years

    Minimum Value

    Maximum Value

    Median Value

    Median TSI Violation?

    Assessment Type

    Support Level

    22320003

    6

    Chlorophyll a TSI

    20 / 4

    31

    83

    66

    YES

    Monitored

    Not

    22320003

    6

    Total Phosphorus TSI

    20 / 4

    63

    84

    78

    NA

    NA

    NA

    22320003

    6

    Inorganic suspended solids

    10 / 2

    0.5

    48

    12.8

    NA

    NA

    NA

    The TSI value for Secchi depth is not used to evaluate the attainment of aquatic life use in shallow lakes. Due to the depth of these shallow lakes, TSI values for Secchi depth can be misleading. In some instances, the Secchi disk remains visible at the bottom of the lake and the depth of the lake is recorded as the Secchi depth. In these instances, water clarity may be sufficient to support the Class B(LW) uses, but the index value is limited by the depth of the lake. Thus the combination of total suspended solids and chlorophyll a will be used to determine whether or not the Class B(LW) uses are impaired in these shallow systems.

    Class BLW - Conventional Parameters:

    Site ID

    Data Source ID

    Parameter Name

    # Samples / # Years

    Minimum Value

    Maximum Value

    Mean Value

    # Violations

    # Acute / Chronic Violations

    Violations needed for impairment

    Violates Significantly >10% Rule?

    Assessment Type

    Support Level

    22320003

    6

    Ammonia

    15 / 3

    0.009

    0.655

    0.11

    NA

    0 / 0

    4

    NO

    Monitored

    Full

    22320003

    6

    Dissolved Oxygen

    20 / 4

    4.06

    14.45

    8.53

    1

    NA / NA

    5

    NO

    Monitored

    Full

    22320003

    6

    pH

    20 / 4

    7.13

    10.98

    8.6

    2

    NA / NA

    5

    NO

    Monitored

    Full

    22320003

    6

    Temperature

    20 / 4

    13.5

    28.9

    22

    0

    NA / NA

    5

    NO

    Monitored

    Full

    Class BLW - Protection of Submerged Aquatic Vegetation:

    Site ID

    Data Source ID

    Parameter Name

    # Samples / # Years

    Minimum Value

    Maximum Value

    Median Value

    Median Value = SAV

    Assessment Type

    Support Level

    22320003

    6

    Total suspended solids

    20 / 4

    6

    76

    34

    Yes

    Monitored

    Not

    Guidelines for wetland assessment from the Upper Mississippi River Conservation Committee’s Water Quality Technical Section (2003) state that an average total suspended solids concentration during the growing season of less than 30 mg/L is necessary to provide sufficient water clarity to support the growth of submersed aquatic vegetation in wetlands and shallow lakes. High levels of total suspended solids impede the growth of submersed aquatic vegetation (SAV). Submersed aquatic vegetation is critical to the health of wetland and shallow lake ecosystems. The elimination of SAV can degrade habitat quality such that undesirable aquatic species such as cyanobacteria, common carp and fathead minnows dominate. As such, the suppression of SAV constitutes a violation of Iowa’s narrative water quality criteria protecting against undesirable or nuisance aquatic life.

    Class HH - Fish Tissue Sampling: No Data

    Additional information:

    Additional monitoring of fish and aquatic vegetation populations at High Lake by DNR staff also suggests that the high levels of total suspended solids and algae have adverse effects on fish populations and limit the production of rooted aquatic vegetation in this wetland. These results further indicate that the aquatic life uses of this wetland should be assessed as "not supported."

Monitoring and Methods
Assessment Key Dates
9/22/2020
Fixed Monitoring Start Date
5/15/2017
Fixed Monitoring End Date
Methods
120
Surveys of fish and game biologists/other professionals
222
Non-fixed-station monitoring (conventional during key seasons and flows)
340
Primary producer surveys (phytoplankton/periphyton/macrophyton)