North River IA 04-LDM-1097

from Co. Rd. R-63 (S16 T77N R24W Warren Co.) to confluence with Badger Cr. in S33 T77N R25W Warren Co.

Assessment Cycle

2022

Release Status

Final

Data Collection Period

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.

Overall IR Category: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown

Created: 12/27/2021 10:32:08 AM
Updated: 1/26/2022 7:41:04 AM

Assessment conducted in accordance with Iowa's 2022 IR methodology

Use Support

Class A1

Recreation

Primary contact

Not Supported

Impairments

Support Level

Not Supported

Impairment Code

5a - Pollutant-caused impairment. TMDL needed.

Cause Magnitude

Moderate

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2008

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Ambient monitoring: Iowa DNR-rivers

TMDL Priority

Tier III

Class BWW1

Aquatic Life

Warm Water Type 1

Not Supported

Impairments

Support Level

Not Supported

Impairment Code

5b-t - Biological - tentative

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2004

Impairment Rationale

Low Biotic Index

Data Source

Biological monitoring: Iowa DNR WQMA

TMDL Priority

Tier IV

Further Investigation Needed

Support Level

Water in Need of Further Investigation (WINOFI)

Impairment Code

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

Cause Magnitude

Slight

Status

New

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2022

Impairment Rationale

Significantly > 10% of days fail to meet 24-hour criteria

Data Source

Ambient monitoring: Iowa DNR-continuous

Class HH

Human Health

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 use was assessed as "not supported" due to levels of indicator bacteria that violated state water quality criteria. The Class BWW1 use was assessed as "not supported” based on biological sampling data and assessed as "WINOFI" based on continuous dissolved oxygen monitoring 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	WQ	CY 2018-2020	10910002	North River near Norwalk
Iowa DNR	6	WQ	CY 2020-2020	14000359	North River at Hwy 28
Iowa DNR	6	BIO	See Below	149	North River	Norwalk
Iowa DNR	6	BIO	See Below	291	North River	Norwalk – REMAP #29

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

10910002

8/7/3

340

280

189

YES

5 / 3

4 / 3

1 / NA

YES

Monitored

Not

14000359

0/0/5

193

YES

2 / NA

Evaluated

Not

Class A - 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
10910002	6	29 / 3	7.2	8.4	7.8	0	6	NO	Monitored	Full
14000359	6	7 / 1	7.7	8.1	7.9	0	3	NO	Evaluated	Full

Class BWW1 - 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
10910002	6	Ammonia	29 / 3	0.02	0.27	0.06	NA	0 / 0	6	NO	Monitored	Full
14000359	6	Ammonia	7 / 1	0.025	0.025	0.02	NA	0 / 0	3	NO	Evaluated	Full
10910002	6	Chloride	30 / 3	9.4	33	14.3	NA	0 / 0	6	NO	Monitored	Full
14000359	6	Chloride	7 / 1	11	16	13	NA	0 / 0	3	NO	Evaluated	Full
10910002	6	Dissolved Oxygen	30 / 3	6.3	13.6	9.7	0	NA / NA	6	NO	Monitored	Full
14000359	6	Dissolved Oxygen	7 / 1	7	13.4	9.9	0	NA / NA	3	NO	Evaluated	Full
10910002	6	pH	29 / 3	7.2	8.4	7.8	0	NA / NA	6	NO	Monitored	Full
14000359	6	pH	7 / 1	7.7	8.1	7.9	0	NA / NA	3	NO	Evaluated	Full
10910002	6	Sulfate	30 / 3	11	31	18	0	NA / NA	6	NO	Monitored	Full
14000359	6	Sulfate	7 / 1	13	31	23	0	NA / NA	3	NO	Evaluated	Full
10910002	6	Temperature	30 / 3	0	27.2	11.9	0	NA / NA	6	NO	Monitored	Full
14000359	6	Temperature	7 / 1	1	27.5	11.8	0	NA / NA	3	NO	Evaluated	Full

Class BWW1 - Toxic Parameters:

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Acute / Chronic Violations	>1 Acute / Chronic Violation	Assessment Type	Support Level
10910002	6	Aluminum	14 / 3	21	2.4	0.57	0 / 0	NO	Monitored	Full
10910002	6	Arsenic	13 / 3	3.2	1.7	1.4	0 / 0	NO	Monitored	Full
10910002	6	Cadmium	13 / 3	0.025	0.025	0.025	0 / 0	NO	Monitored	Full
10910002	6	Chromium	13 / 3	0.91	0.57	0.68	0 / 0	NO	Monitored	Full
10910002	6	Lead	13 / 3	0.15	0.09	0.09	0 / 0	NO	Monitored	Full
10910002	6	Nickel	13 / 3	3.3	2.7	2.8	0 / 0	NO	Monitored	Full
10910002	6	Silver	13 / 3	0.025	0.025	0.025	0 / 0	NO	Monitored	Full
10910002	6	Zinc	13 / 3	4.5	1.6	1.1	0 / 0	NO	Monitored	Full

Class BWW1 - Biological Sampling:

Benthic Macroinvertebrates:

Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	BM Sample Gear	BMIBI score	BMIBI Class	47f BMIBI BIT	BMIBI Pass/ Fail
291	9/5/19	341	47f	MS	Floating Art Sub	67	Good	51	Pass
149	8/17/17	339	47f	MS	Art Sub	44	Fair	51	Fail

Fish:

Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	Riffle Stream?	FIBI score	FIBI Class	47f FIBI BIT	FIBI Pass/ Fail
149	8/17/17	339	47f	MS	NA	24	Poor	36	Fail

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Fail (1/2)	Not
Fish	Evaluated	Fail (0/1)	Not		Assessment was evaluated because the BMIBI assessment was inconclusive
Overall	Evaluated	Fail	Not	5bt	and the FIBI assessment was based on a single sample.

Class BWW1- Continuous DO Monitoring:

Site ID	Data Source ID	# Days Monitoring (2016/2017/2018/ 2019/2020)	DO Criteria Type	# 2016 violations / Violations needed for impairment	# 2017 violations / Violations needed for impairment	# 2018 violations / Violations needed for impairment	# 2019 violations / Violations needed for impairment	# 2020 violations / Violations needed for impairment	Violates Annual Significantly >10% Rule?	Assessment Type	Support Level
			24 hr	NA	NA	5/5	1/4	NA	Yes
291	6	0/0/20/18/0	16 hr	NA	NA	3/5	0/4	NA	No	Evaluated	WINOFI

Class HH – No Data

Monitoring and Methods

Assessment Key Dates

8/17/2017

Biological Monitoring

9/5/2019

Biological Monitoring

1/3/2018

Fixed Monitoring Start Date

12/8/2020

Fixed Monitoring End Date

Methods

222

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

230

Fixed station physical/chemical (conventional plus toxic pollutants)

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

330

Fish surveys

380

Quantitative physical habitat assessment

420

Indicator bacteria monitoring