Prairie Rose Lake IA 05-NSH-1462

Shelby County S36T79NR38W 6 mi SE of Harlan.

Open Data Collection Period Modal

For purposes of developing stream/river water quality assessments for integrated reporting, three years of water quality data are typically used for both conventional pollutant parameters (e.g., indicator bacteria) and the less frequently monitored toxic parameters (e.g., toxic metals). Since the 2004 IR cycle, DNR has used a three-year data gathering period for streams, rivers, and beaches. For most assessments, the use of three years of data increases the number of samples upon which the decision on use support is based and helps address the problem of weather-related year-to-year fluctuations in water quality.

Due to the lower sampling frequency in Iowa’s ambient lake, biological, fish kill, and fish tissue monitoring programs, five years of data are used for developing IR assessments and for identifying Section 303(d) listings.

Data Type	Data Timeframe
Beach Sampling Data	CY 2018 - 2020
Stream/River Water Quality Data	CY 2018 - 2020
Lake Water Quality Data	CY 2016 - 2020
Biological Sampling Data	CY 2016 - 2020*
Fish Kill Data	CY 2016 - 2020
Fish Tissue Sampling Data	CY 2016 - 2020
Continuous Dissolved Oxygen Sampling Data	CY 2016 - 2020
*Biological sites sampled in both 2015 and 2019 were also assessed.

Open Segment Map
View assessment methodology in new window

Cycle: 2022
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trophic: Eutrophic
Trend: Stable
Created: 12/30/2021 4:08:31 PM
Updated: 3/24/2022 2:11:23 PM

Use Support

Class A1

Recreation - Primary contact

Not Supported

Bacteria: Indicator Bacteria- E. coli

Support Level

Not Supported

Impairment Code

5a - Pollutant-caused impairment. TMDL needed.

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2012

Impairment Rationale

Single-sample maximum criterion exceeded in significantly > 10% of samples

Data Source

Beach monitoring: Iowa DNR WQMA

TMDL Priority

Tier II

Algal Growth: Chlorophyll a

Support Level

Not Supported

Impairment Code

4a - Pollutant-caused impairment. TMDL has been completed.

Cause Magnitude

Moderate

Status

Delisted

Source

Natural: Internal Nutrient Recycling (Primarily Lakes)

Source Confidence

Moderate

Cycle Added

2004

Impairment Rationale

Narrative criteria violation: aesthetically objectionable conditions

Cycle Delisted

2022

Delisting Rationale

TMDL preparation and approval

Data Source

TMDL monitoring: Iowa DNR

Turbidity

Support Level

Not Supported

Impairment Code

4a - Pollutant-caused impairment. TMDL has been completed.

Cause Magnitude

Slight

Status

Delisted

Source

Agriculture

Source Confidence

Moderate

Cycle Added

2004

Impairment Rationale

Narrative criteria violation: aesthetically objectionable conditions

Cycle Delisted

2022

Delisting Rationale

TMDL preparation and approval

Data Source

TMDL monitoring: Iowa DNR

Class BLW

Aquatic Life - Lakes and wetlands

Fully Supported

Class C

Drinking Water -

Fully Supported

Class HH

Human Health -

Fully Supported

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 by algae blooms and non-algal turbidity. In addition, violations of the state's water quality standard for indicator bacteria also suggested an impairment at Prairie Rose Lake. The Class BLW use was assessed (monitored) as “fully supported.” The Class C (drinking water) use was assessed (monitored) as “fully supported.” The Class HH (fish consumption) use was assessed (monitored) as “fully supported” based on fish tissue sampling data. Note: A TMDL for algae and turbidity at Prairie Rose lake was prepared by DNR and approved by EPA in 2020. Not all Section 303(d) impairments identified for the current assessment/listing cycle (E. coli) are addressed in the TMDL. Thus, this waterbody remains in IR Category 5a (impaired; TMDL required.)

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	WQ	CY 2018-2020	21830001	Prairie Rose Beach (Prairie Rose State Park)
Iowa DNR	6	WQ	CY 2016-2020	22830002	Prairie Rose Lake
Iowa DNR	6	WQ	CY 2016-2017	14000214	Pr Rose 1
Iowa DNR	6	WQ	CY 2016-2017	14000215	Pr Rose 2
Iowa DNR	6	FT	See Below	108	Prairie Rose Lake	near Harlan

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

21830001

15/14/14

104

4 / 4

YES

Monitored

Not

22830002

3/3/3

0 / NA

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
14000214	6	13 / 1	7.6	9	8.4	0	4	NO	Monitored	Full
14000215	6	13 / 1	7.5	9.1	8.4	2	4	NO	Monitored	Full
22830002	6	28 / 5	7.4	9.2	8.4	2	6	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
22830002	6	Chlorophyll a TSI	44 / 5	26	79	66	YES	Monitored	Not
22830002	6	Secchi TSI	15 / 5	45	77	67	YES	Monitored	Not
22830002	6	Total Phosphorus TSI	44 / 5	37	82	71	NA	NA	NA
22830002	6	Fixed suspended solids	15 / 5	0.3	7	1.1	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
14000214	6	Ammonia	11 / 1	0.02	0.55	0.09	NA	0 / 0	3	NO	Monitored	Full
14000215	6	Ammonia	11 / 1	0.02	0.64	0.1	NA	0 / 0	3	NO	Monitored	Full
22830002	6	Ammonia	25 / 5	0.0012	0.76	0.08	NA	0 / 0	5	NO	Monitored	Full
14000214	6	Dissolved Oxygen	13 / 1	6.5	12.2	9.8	0	NA / NA	4	NO	Monitored	Full
14000215	6	Dissolved Oxygen	13 / 1	5.9	12.4	9.2	0	NA / NA	4	NO	Monitored	Full
22830002	6	Dissolved Oxygen	28 / 5	3.7	13.5	8.5	3	NA / NA	6	NO	Monitored	Full
14000214	6	pH	13 / 1	7.6	9	8.4	0	NA / NA	4	NO	Monitored	Full
14000215	6	pH	13 / 1	7.5	9.1	8.4	2	NA / NA	4	NO	Monitored	Full
22830002	6	pH	28 / 5	7.4	9.2	8.4	2	NA / NA	6	NO	Monitored	Full
14000214	6	Temperature	13 / 1	10.5	28	20	0	NA / NA	4	NO	Monitored	Full
14000215	6	Temperature	13 / 1	10.1	27.8	20	0	NA / NA	4	NO	Monitored	Full
22830002	6	Temperature	29 / 5	10.4	28.6	22.7	0	NA / NA	6	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
22830002	6	6	12.52932836	96.84%	6.182565206	57.57%	NO	Evaluated	NA

Class C - Conventional Parameters:

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Minimum Value	Maximum Value	Mean Value	Median Value	# Violations	Violates Significantly >10% Rule?	Assessment Type	Support Level
14000214	6	Chloride	29 / 2	10	14	12	12	0	NO	Monitored	Full
14000215	6	Chloride	30 / 2	10	14	12	12	0	NO	Monitored	Full
22830002	6	Chloride	29 / 2	10	16	12	12	0	NO	Monitored	Full
14000214	6	Inorganic nitrogen (nitrate and nitrite)	29 / 2	0.05	3.1	0.8	0.2	0	NO	Monitored	Full
14000215	6	Inorganic nitrogen (nitrate and nitrite)	29 / 2	0.05	3.1	0.8	0.2	0	NO	Monitored	Full
22830002	6	Inorganic nitrogen (nitrate and nitrite)	44 / 5	0.02	3.1	0.6	0.05	0	NO	Monitored	Full
14000214	6	pH	13 / 1	7.6	9	8.4	8.5	0	NO	Monitored	Full
14000215	6	pH	13 / 1	7.5	9.1	8.4	8.4	2	NO	Monitored	Full
22830002	6	pH	28 / 5	7.4	9.2	8.4	8.4	2	NO	Monitored	Full

Class HH - Fish Tissue Sampling:

Site ID	Biopart	Year	Species	# in sample / # of samples	Avg Length (cm)	(Avg) Hg (ppm)	Chlordane (ppm)	Sum PCBs (ppm)
108	tissue plug	2019	bluegill	10	22.9	0.06
108	tissue plug	2019	largemouth bass	10	31.6	0.206
Support Level	Full

Monitoring and Methods

Assessment Key Dates

4/13/2016

Fixed Monitoring Start Date

8/31/2020

Fixed Monitoring End Date

7/1/2019

Fish Tissue Monitoring

12/3/2020

TMDL Completed

Methods

120

Surveys of fish and game biologists/other professionals

222

Non-fixed-station monitoring (conventional during key seasons and flows)

260

Fish tissue analysis

340

Primary producer surveys (phytoplankton/periphyton/macrophyton)

420

Indicator bacteria monitoring