Cedar Lake IA 04-LDM-1101

Madison County S19T76NR27W near Winterset.

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.

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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: Unknown
Trend: Stable
Created: 12/28/2021 11:18:02 AM
Updated: 1/27/2022 6:57:45 AM

Use Support

Class BLW

Aquatic Life - Lakes and wetlands

Not Assessed

Class C

Drinking Water -

Fully Supported

Class HH

Human Health -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class C use was assessed (monitored) as "fully supported" based on compliance monitoring. All other designated uses were “not assessed.” Note: A TMDL for nitrate at Cedar Lake was prepared by DNR and approved by EPA in 2005. A TMDL for atrazine at Cedar Lake was prepared by DNR and approved by EPA in 2010.

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	22610005	Cedar Lake

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
22610005	6	Ammonia	9 / 3	0.0012	0.1559	0.04	NA	0 / 0	3	NO	Evaluated	Full
22610005	6	Dissolved Oxygen	9 / 3	5.1	15.2	8.1	0	NA / NA	3	NO	Evaluated	Full
22610005	6	pH	9 / 3	8.1	9	8.5	0	NA / NA	3	NO	Evaluated	Full
22610005	6	Temperature	9 / 3	20.4	27.9	25.1	0	NA / NA	3	NO	Evaluated	Full

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
22610005	6	Inorganic nitrogen (nitrate and nitrite)	9 / 3	0.03	6.34	2.78	1.3	0	NO	Evaluated	Full
22610005	6	pH	9 / 3	8.1	9	8.5	8.4	0	NO	Evaluated	Full

Class C - City drinking water program compliance reports from years 2016 through 2019:

The Class C use was assessed as "fully supported" due to a lack of violations from the Winterset Municipal Waterworks during the period 2016 through 2019.

Class HH: No Data

Monitoring and Methods

Assessment Key Dates

5/29/2018

Fixed Monitoring Start Date

8/24/2020

Fixed Monitoring End Date

6/6/2005

TMDL Completed

3/19/2010

TMDL Completed

Methods

222

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

270

PWS chemical monitoring (ambient water)

275

Drinking water compliance reports