Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Rice Lake IA 02-WIN-832

Winnebago County S13T99NR23W at SE edge of Lake Mills.

Cycle
2022
Release Status
Final
Overall IR
5 - Water is impaired or threatened and a TMDL is needed.
Trend
Stable
Created
12/22/2021 1:07:33 PM
Updated
2/17/2022 2:45:04 PM
Use Support
Class A1
Recreation - Primary contact
Not Supported
Support Level
Not Supported
Impairment Code
5a - Pollutant-caused impairment. TMDL needed.
Cause Magnitude
Moderate
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
2020
Impairment Rationale
Significantly > 10% of samples fail to meet criterion
Data Source
Ambient monitoring: Iowa DNR-shallow lakes & wetlands
TMDL Priority
Tier IV
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
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
2020
Impairment Rationale
Significantly > 10% of samples fail to meet criterion
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 as "not supported" due to violations of the Class A1 criterion for pH. The Class BLW use was assessed as "not supported" due to violations of the Class BLW criterion for pH. 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 2016-2020

22950001

Rice 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

22950001

6

25 / 5

7.9

12.4

9.2

13

5

YES

Monitored

Not

Class A1 - 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

22950001

6

Chlorophyll a TSI

25 / 5

24

81

57

NO

Monitored

Full

22950001

6

Inorganic suspended solids

15 / 3

0

32

2

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

22950001

6

Ammonia

20 / 4

0.01

0.39

0.07

NA

0 / 1

5

NO

Monitored

Full

22950001

6

Dissolved Oxygen

24 / 5

4.57

17.16

9.42

1

NA / NA

5

NO

Monitored

Full

22950001

6

pH

25 / 5

7.9

12.4

9.2

13

NA / NA

5

YES

Monitored

Not

22950001

6

Temperature

25 / 5

12.6

28.8

21.6

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

22950001

6

Total suspended solids

25 / 5

0.5

40

9

NO

Monitored

Full

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 : No Data

Monitoring and Methods
Assessment Key Dates
5/16/2016
Fixed Monitoring Start Date
9/10/2020
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)