Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Pleasant Creek Lake IA 02-CED-459

Linn County S31T85NR8W 4 mi. NNW of Palo.

Cycle
2022
Release Status
Final
Overall IR
2 - Some of the designated uses are met but there is insufficient data to determine if remaining designated uses are met.
Trophic
Eutrophic
Trend
Stable
Created
12/17/2021 10:24:38 AM
Updated
1/7/2022 7:53:22 AM
Use Support
Class A1
Recreation - Primary contact
Fully Supported
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 as “fully supported.” The Class BLW use was assessed as “fully supported.” 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 2019-2020

21570001

Pleasant Creek Beach (Pleasant Creek State Park)

Iowa DNR

6

WQ

CY 2016-2020

22570001

Pleasant Creek Lake

Class A1 - Indicator Bacteria:

Site ID

Data Source ID

# Samples per Year (2018/ 2019/2020)

2018 Geometric Mean

2019 Geometric Mean

2020 Geometric Mean

Violates Annual Geometric Mean?

# 2018 SSM violations / SSM Violations needed for impairment

# 2019 SSM violations / SSM Violations needed for impairment

# 2020 SSM violations / SSM Violations needed for impairment

Violates Annual SSM Significantly >10% Rule?

Assessment Type

Support Level

21570001

6

0/15/13

NA

34

33

NO

NA

2 / 4

2 / 4

NO

Monitored

Full

22570001

6

3/3/3

5

5

5

NO

0 / NA

0 / NA

0 / NA

NO

Evaluated

Full

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

22570001

6

15 / 5

7.6

8.8

8.2

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

22570001

6

Chlorophyll a TSI

15 / 5

35

76

57

NO

Monitored

Full

22570001

6

Secchi TSI

15 / 5

41

70

60

NO

Monitored

Full

22570001

6

Total Phosphorus TSI

15 / 5

37

71

57

NA

NA

NA

22570001

6

Inorganic suspended solids

15 / 5

0.6

9.8

1

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

22570001

6

Ammonia

15 / 5

0.0003

0.232

0.05

NA

0 / 0

4

NO

Monitored

Full

22570001

6

Dissolved Oxygen

15 / 5

3.4

12.1

8.3

2

NA / NA

4

NO

Monitored

Full

22570001

6

pH

15 / 5

7.6

8.8

8.2

0

NA / NA

4

NO

Monitored

Full

22570001

6

Temperature

15 / 5

20.1

26.9

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

22570001

6

6

29.66

86.5%

1.10

17.0%

NO

Evaluated

NA

Class HH – No Data

Monitoring and Methods
Assessment Key Dates
6/22/2016
Fixed Monitoring Start Date
9/16/2020
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)
340
Primary producer surveys (phytoplankton/periphyton/macrophyton)