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 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.
Trend: Unknown
Created: 12/20/2021 1:35:16 PM
Updated: 1/6/2022 9:11:33 AM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Supported

Bacteria: Indicator Bacteria- E. coli

Support Level

Not 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

Recreation - Secondary contact

Not Supported

Bacteria: Indicator Bacteria- E. coli

Support Level

Not 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

Not Supported

Biological: low aquatic macroinvertebrate IBI

Support Level

Not Supported

Impairment Code

5b-v - Biological - verified

Cause Magnitude

Slight

Status

New

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2022

Impairment Rationale

Low Biotic Index

Data Source

Biological monitoring: Iowa DNR WQMA

TMDL Priority

Tier IV

Class HH

Human Health -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class A1 and the Class A2 uses remain assessed as “not supported” due to levels of indicator bacteria that exceeded state water quality criteria. The Class BCW1 use was assessed as "not supported" based on biological sampling data. 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	BIO	See Below	360	Waterloo Creek	Dorchester – REMAP #63
Iowa DNR	6	BIO	See Below	802	Waterloo Creek	Dorchester
Iowa DNR	6	WQ	CY 2012-2014	190050003	Waterloo Creek	Site 26

Presumptive Class A1 - Indicator Bacteria: 2012-2014

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	Not

Class A2 - Indicator Bacteria: 2012-2014

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 current 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. As described in the 2014 assessment of this stream segment, the Class A2 use was previously assessed as "impaired". Thus, the Class A2 use will remain in Category 5a 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:

Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	BM Sample Gear	CBI score	CBI Class	CBI BIT	CBI Pass/ Fail
802	9/1/20	34.2	52b	MS	Hess	56	NA	60	Fail
360	7/16/19	23.2	52b	MS	Hess	48	NA	60	Fail
802	8/10/16	34.2	52b	MS	Hess	51	NA	60	Fail

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Monitored	Fail (0/3)	Not		Assessment was monitored because the assessment used multiple
Overall	Monitored	Fail	Not	5bv	samples collected in a recent five year period to complete the assessment.

Class BCW1 – Trout Natural Reproduction:

In contrast to the Benthic Macroinvertebrate data, based on the January 2021 trout reproduction in Iowa streams summary 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 both 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

4/3/2012

Non-fixed Monitoring Start Date

10/7/2014

Non-fixed Monitoring End Date

1/1/2021

Biological Monitoring

9/1/2020

Biological Monitoring

7/16/2019

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

380

Quantitative physical habitat assessment

420

Indicator bacteria monitoring