Lake Icaria IA 05-NOD-1398

Adams County S10T72NR34W 4 mi N of Corning.

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 2016 - 2018
Stream/River Water Quality Data	CY 2016 - 2018
Lake Water Quality Data	CY 2014 - 2018
Biological Sampling Data	CY 2014 - 2018*
Fish Kill Data	CY 2014 - 2018
Fish Tissue Sampling Data	CY 2014 - 2018
Continuous Dissolved Oxygen Sampling Data	CY 2014 - 2018
*Biological sites sampled in both 2013 and 2017 were also assessed.

Open Segment Map
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Cycle: 2020
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: 8/25/2020 1:17:46 PM
Updated: 10/15/2020 7:40:37 AM

Use Support

Class A1

Recreation - Primary contact

Partially Supported

Turbidity

Support Level

Partially Supported

Impairment Code

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

Cause Magnitude

Slight

Status

Continuing

Source

Other: Sediment Resuspension

Source Confidence

Moderate

Cycle Added

2014

Impairment Rationale

Narrative criteria violation: aesthetically objectionable conditions

Data Source

Ambient monitoring: Iowa DNR-lakes

Class BLW

Aquatic Life - Lakes and wetlands

WINOFI

Turbidity: Suspended Solids

Support Level

Further Investigation Needed

Impairment Code

3b - Use potentially impaired based on an evaluated assessment.

Cause Magnitude

Moderate

Status

Continuing

Source

Other: Exotic Species

Source Confidence

Moderate

Cycle Added

2016

Impairment Rationale

Adverse impacts on plant/animal communities

Data Source

Biological monitoring: Iowa DNR Fisheries

Class C

Drinking Water -

Not Assessed

Class HH

Human Health -

Fully Supported

General Use

General Use water -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 uses are assessed (monitored) as “partially supported” due to aesthetically objectionable conditions caused by poor water clarity. The Class BLW uses are assessed (monitored) as “fully supported.” The Class C uses remain “not assessed” due to a lack of enough monitoring data. Class HH uses are assessed (monitored) as "fully supported" based on results of fish tissue monitoring. Note: A TMDL for siltation at Lake Icaria was prepared by DNR and approved by EPA in 2003. Since all impairments for Lake Icaria were addressed in the TMDL, it will be listed as Category 4a for the current assessment/listing cycle.

Assessment Explanation

Sources of Data:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	WQ	CY 2014-2018	22020001	Lake Icaria	Lake Deep Point
Iowa DNR		FT	See Below	59	Lake Icaria

Class A1 - Indicator Bacteria: No Data

Class A1 - pH:

Site ID	Data Source ID	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
22020001	6	14 / 5	8.6	8.1	8.2	0	0%	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
22020001	6	Chlorophyll a TSI	15 / 5	31	73	59	NO	Monitored	Full
22020001	6	Secchi TSI	15 / 5	51	77	64	NO	Monitored	Full
22020001	6	Total Phosphorus TSI	15 / 5	49	76	61	NA	NA	NA
22020001	6	Inorganic suspended solids	15 / 5	1	11	3	NA	NA	NA

Although the index value for Secchi is below the impairment trigger of 65 for this assessment cycle, Lake Icaria was listed as partially supporting its Class A1 uses due to aesthetically objectionable conditions. Based on DNR's methodology, the median TSI value for Secchi must be 63 or less for two consecutive assessment/listing cycles before a lake can be removed from the state's Section 303(d) list (IR Category 5). Therefore, Lake Icaria will remain listed as "not supported" for the 2020 assessment/listing cycle.

Class BLW - Conventional Parameters:

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Acute / Chronic Violations	% Acute/ Chronic Violations	Significantly >10% Violations	Assessment Type	Support Level
22020001	6	Ammonia	14 / 5	0.328	0.12	0.09	0 / 0	0% / 0%	NO	Monitored	Full
22020001	6	Dissolved oxygen	15 / 5	9.99	6.62	7.1	NA / 3	NA / 20%	NO	Monitored	Full
22020001	6	pH	14 / 5	8.6	8.1	8.2	0 / NA	0% / NA	NO	Monitored	Full
22020001	6	Temperature	15 / 5	28.6	24.2	24.1	0 / 0	0% / 0%	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 Wet Mass = 75th Percentile	Assessment Type	Support Level
22020001	6	11	48.547	98.9 %	21.321	93.4 %	NO	Evaluated	NA

Class C - Conventional Parameters:

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
22020001	6	Inorganic nitrogen (nitrate and nitrite)	15 / 5	1.8	0.53	0.2	0	0%	NO	Monitored	Full

The Class C uses are not assessed due to the lack of data sufficient for developing a valid assessment of support of the Class C uses.

Class HH - Fish Tissue Sampling:

Site ID

Date

Species Name

Biopart

# in sample

chlordane result

chlordane violation?

PCBs result

PCBs violation?

Hg result

Hg violation?

Assessment Type

Support Level

9/3/10

channel catfish

fillet

<0.03

<0.09

0.0322

Evaluated

Full

9/3/10

largemouth bass

fillet

0.21

Evaluated

Full

Note: The City of Corning applies copper sulfate (an algaecide) to Lake Icaria in the event of an algae bloom (Iowa Water Web).

Monitoring and Methods

Assessment Key Dates

6/16/2014

Fixed Monitoring Start Date

8/26/2018

Fixed Monitoring End Date

9/3/2010

Fish Tissue Monitoring

1/30/2003

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)