North Raccoon River IA 04-RAC-1139

from County Road M54 (S24T88N R36W Sac Co.) to confluence with Drainage Ditch 101 in S36 T91N R36W Buena Vista 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 2020 - 2022
Stream/River Water Quality Data	CY 2020 - 2022
Lake Water Quality Data	CY 2018 - 2022
Biological Sampling Data	CY 2018 - 2022*
Fish Kill Data	CY 2018 - 2022
Fish Tissue Sampling Data	CY 2018 - 2022
Continuous Dissolved Oxygen Sampling Data	CY 2018 - 2022
*Biological sites sampled in both 2017 and 2021 were also assessed.

Open Segment Map
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Cycle: 2024
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown
Created: 11/1/2023 8:12:29 AM
Updated: 4/19/2024 10:27:49 AM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Supported

Bacteria: Indicator Bacteria- E. coli

Support Level

Not Supported

Impairment Code

5a - Pollutant-caused impairment. TMDL needed.

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2010

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Ambient monitoring: Iowa DNR-rivers

TMDL Priority

Tier II

Class BWW1

Aquatic Life - Warm Water Type 1

Not Supported

Biological: low aquatic macroinvertebrate IBI

Support Level

Not Supported

Impairment Code

5b-t - Biological - tentative

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2006

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 use was assessed as "not supported" due to levels of indicator bacteria (E. coli) that violated state water quality criteria. The Class BWW1 use was assessed as "not supported” based on biological sampling data. All other designated uses were "not assessed." The presumptive Class A1 use of this segment resided in Category 4a from 2010-2022; however, the 2008 Raccoon River TMDL did not include this segment.

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	WQ	CY 2012-2014	10810002	North Raccoon River US of Sac City (US1)
Iowa DNR	6	BIO	See Below	143	North Raccoon River	Raccoon River Greenbelt – Sac City
Iowa DNR	6	BIO	See Below	1157	North Raccoon River	Sac City – REMAP #443

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
10810002	6	22 / 3	70	148	274	Yes	9	41%	Yes	Evaluated	Not

Presumptive 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
10810002	6	33 / 3	9	8.26	8.3	0	0%	No	Evaluated	Full

Class BWW1 - Binomial 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
10810002	6	Ammonia	33 / 3	1.7	0.18	0.05	0 / 0	0% / 0%	No	Evaluated	Full
10810002	6	Chloride	33 / 3	140	63	63	0 / 0	0% / 0%	No	Evaluated	Full
10810002	6	Dissolved oxygen	33 / 3	17.3	10.7	10.2	NA / 0	NA / 0%	No	Evaluated	Full
10810002	6	pH	33 / 3	9	8.26	8.3	0 / NA	0% / NA	No	Evaluated	Full
10810002	6	Sulfate	33 / 3	410	173	170	0 / NA	0% / NA	No	Evaluated	Full
10810002	6	Temperature	33 / 3	29.5	11.3	9.8	0 / 0	0% / 0%	No	Evaluated	Full

Class BWW1 - Biological Sampling:

Benthic Macroinvertebrates:

Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	BM Sample Gear	BMIBI score	BMIBI Class	47b BMIBI BIT	BMIBI Pass/Fail
143	9/24/19	328	47b	MS	Hess	65	Good	62	Pass
1157	9/18/17	330	47b	MS	Hess	54	Fair	62	Fail
143	8/13/15	328	47b	MS	Hess	62	Good	62	Pass

Fish:

Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	Riffle Stream?	FIBI score	FIBI Class	47b FIBI BIT	FIBI Pass/Fail
143	9/24/19	328	47b	MS	Yes	62	Good	53	Pass
1157	9/18/17	330	47b	MS	No	72	Excellent	32	Pass

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Pass (2/3)	Full
Fish	Evaluated	Pass (2/2)	Full		Assessment was evaluated because one of the samples used
Overall	Evaluated	Pass	Full	5bt	to complete the assessment was greater than five years old.

Class HH – No Data

Monitoring and Methods

Assessment Key Dates

9/24/2019

Biological Monitoring

1/9/2012

Monitoring Start

9/8/2014

Monitoring End

8/13/2015

Biological Monitoring

9/18/2017

Biological Monitoring

Methods

150

Monitoring data more than 5 years old

200

Physical/Chemical Monitoring

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

330

Fish surveys

420

Indicator bacteria monitoring