Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Spring Lake IA 04-RAC-1152

Greene County S25T84NR30W 3 mi NW of Grand Junction.

Cycle
2022
Release Status
Final
Overall IR
4 - Water is impaired or threatened and a TMDL has been completed or is not needed.
Trophic
Eutrophic
Trend
Stable
Created
12/28/2021 1:33:22 PM
Updated
2/4/2022 7:20:10 AM
Use Support
Class A1
Recreation - Primary contact
Not Supported
Support Level
Not Supported
Impairment Code
4a - Pollutant-caused impairment. TMDL has been completed.
Cause Magnitude
High
Status
Continuing
Source
Other: Sediment Resuspension
Source Confidence
High
Cycle Added
2004
Impairment Rationale
Narrative criteria violation: aesthetically objectionable conditions
Data Source
Ambient monitoring: Iowa DNR-lakes
Class BLW
Aquatic Life - Lakes and wetlands
Fully Supported
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 “not supported” due to poor water transparency caused mainly by inorganic suspended solids that violated Iowa’s narrative water quality standard protecting against aesthetically objectionable conditions. The Class BLW use was assessed (monitored) as "fully supported." All other designated uses were “not assessed.” Note: A TMDL for turbidity at Spring Lake was prepared by DNR and approved by EPA in 2006. Because the primary Section 303(d) impairment identified for the current assessment/listing cycle (turbidity) was addressed by the TMDL, this waterbody was placed in IR Category 4a (impaired; TMDL approved).

Assessment Explanation

Data Sources:

Data Source

Data Source ID

Data Type

Data Age

Site ID

Site Name

Site Description

Iowa DNR

6

WQ

CY 2016-2019

22370001

Spring Lake Max Depth

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

22370001

6

12 / 4

8

8.9

8.5

0

4

NO

Monitored

Full

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

22370001

6

Chlorophyll a TSI

12 / 4

26

73

59

NO

Monitored

Full

22370001

6

Secchi TSI

12 / 4

67

83

74

YES

Monitored

Not

22370001

6

Total Phosphorus TSI

12 / 4

60

77

67

NA

NA

NA

22370001

6

Inorganic suspended solids

12 / 4

0.6

21.4

5

NA

NA

NA

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

22370001

6

Ammonia

12 / 4

0.0003

0.1141

0.02

NA

0 / 0

4

NO

Monitored

Full

22370001

6

Dissolved Oxygen

12 / 4

8.5

11.2

9.5

0

NA / NA

4

NO

Monitored

Full

22370001

6

pH

12 / 4

8

8.9

8.5

0

NA / NA

4

NO

Monitored

Full

22370001

6

Temperature

12 / 4

14.9

28.6

23.5

0

NA / NA

4

NO

Monitored

Full

Class BLW - Lake Planktonic Cyanobacteria:

Site ID

Data Source ID

# Samples

Maximum Cyanobacteria Wet Mass

Maximum Cyanobacteria % Composition

Median Cyanobacteria Wet Mass

Median Cyanobacteria % Composition

Median Cyanobacteria Concentration = 75th Percentile

Assessment Type

Support Level

22370001

6

6

21.23

79.6%

6.75

71.1%

NO

Evaluated

NA

Class HH: No Data

Monitoring and Methods
Assessment Key Dates
5/16/2016
Non-fixed Monitoring Start Date
8/20/2019
Non-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)
420
Indicator bacteria monitoring