Waterloo Creek IA 01-UIA-253

mouth (S35 T100N R6W Allamakee Co.) to IA/MN state line (S9 T100N R6W Allamakee Co.)

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: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown
Created: 8/24/2020 1:26:08 PM
Updated: 10/15/2020 10:42:20 AM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Partially Supported

Bacteria: Indicator Bacteria- E. coli

Support Level

Partially Supported

Impairment Code

5p - Impairment occurs on a waterbody with a presumptive A1 or B(WW1) use.

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2008

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Watershed project monitoring

TMDL Priority

Tier III

Class A2

Presumptive Use

Recreation - Secondary contact

Partially Supported

Bacteria: Indicator Bacteria- E. coli

Support Level

Partially Supported

Impairment Code

5p - Impairment occurs on a waterbody with a presumptive A1 or B(WW1) use.

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2012

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Watershed project monitoring

TMDL Priority

Tier III

Class BCW1

Aquatic Life - Cold Water Type 1

Fully Supported

Class HH

Human Health -

Not Assessed

General Use

General Use water -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class A1 and the presumptive Class A2 uses remain assessed as “partially supported” due to levels of indicator bacteria that exceeded state water quality criteria. The Class BCW1 use remains assessed "fully supported" based on biological sampling data, water quality monitoring data, and also based on the trout reproduction in Iowa streams summary prepared by the DNR Fisheries Bureau. All other designated uses were "not assessed".

Assessment Explanation

Sources of Data:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	BIO	See Below	360	Waterloo Creek	Dorchester – REMAP #63
Iowa DNR	6	BIO	See Below	802	Waterloo Creek	Dorchester
Iowa DNR	6	BIO	See Below	902	Waterloo Creek	Bee4 MN
Iowa DNR	6	BIO	See Below	903	Waterloo Creek	Dorchester (pasture) – Waterloo1
Iowa DNR	6	BIO	See Below	904	Waterloo Creek	Dorchester – Waterloo5
NEIARCD	19	WQ	CY2012-2014	190050003	Waterloo Creek	Site 26

Presumptive Class A1 - Indicator Bacteria:

Site ID	Data Source ID	# Samples / # Years	2012 Geometric Mean	2013 Geometric Mean	2014 Geometric Mean	Annual Geometric Mean Violation	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
190050003	19	21 / 3	112	273	237	Yes	8	38%	Yes	Evaluated	Partial

Presumptive Class A2 - Indicator Bacteria:

Site ID	Data Source ID	# Samples / # Years	2012 Geometric Mean	2013 Geometric Mean	2014 Geometric Mean	Annual Geometric Mean Violation	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
190050003	19	21 / 3	112	273	237	No	2	9.5%	No	Evaluated	Full
Although indicating full support, Iowa DNR’s IR methodology requires that both geometric mean criteria and single-sample maximum criteria be met for two consecutive IR cycles (five years) before a bacteria impairment can be removed. This methodology is designed to prevent impairment flip-flopping with highly variable and weather-influenced parameters such as indicator bacteria. As described in the 2014 assessment of this stream segment, the Class A2 uses were previously assessed as "impaired". Thus, the Class A2 uses will remain assessed as “partially supported” for the current IR cycle.

Class A - pH:

Site ID	Data Source ID	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
190050003	19	14 / 3	8.86	8.49	8.56	0	0%	No	Evaluated	Full

Class BCW1 - 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
190050003	19	Ammonia	14 / 3	0.17	0.06	0.05	0 / 0	0% / 0%	No	Evaluated	Full
190050003	19	pH	14 / 3	8.86	8.49	8.56	0 / 0	0% / 0%	No	Evaluated	Full
190050003	19	Temperature	14 / 3	19.2	14.2	15.6	NA / 0	NA / 0%	No	Evaluated	Full

Class BCW1 - Biological Sampling:

Benthic Macroinvertebrates:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage/ Thermal	BM Sample Gear	CBI score	CBI Class	CBI BIT	CBI Pass/ Fail
802	8/10/16	23	52b	MS/CW	Hess	51	NA	60	Fail
360	7/21/15	23	52b	MS/CW	Hess	76	NA	60	Pass
902	8/1/12	34	52b	MS/CW	Hess	90	NA	60	Pass
903	8/1/12	19	52b	MS/CW	Hess	75	NA	60	Pass
904	8/1/12	34	52b	MS/CW	Hess	49	NA	60	Fail

Overall Assessment:

Community	Assessment Type	Assessment Result	Support Level	Earned IR Category	Actual IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Pass (3/5)	Full	1	1	Assessment is evaluated because samples used to complete assessment weren’t collected in the last five years.

Class BCW1 – Trout Natural Reproduction:

Based on the January 2020 summary of trout reproduction in Iowa streams prepared by the DNR Fisheries Bureau, the Class BCW1 coldwater aquatic life use of Waterloo Creek was assessed as "fully supported". According to the updated summary, this stream was placed in Category I: streams that exhibit consistent natural reproduction and maintain a wild population of one or more trout species without any stocking.

Class HH - No Data

Monitoring and Methods

Assessment Key Dates

8/10/2016

Biological Monitoring

8/1/2012

Biological Monitoring

4/3/2012

Non-fixed Monitoring Start Date

10/7/2014

Non-fixed Monitoring End Date

1/1/2020

Biological Monitoring

7/21/2015

Biological Monitoring

Methods

120

Surveys of fish and game biologists/other professionals

150

Monitoring data more than 5 years old

220

Non-fixed station physical/chemical monitoring (conventional pollutant only)

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

330

Fish surveys

420

Indicator bacteria monitoring