South Raccoon River IA 04-RAC-1183

from confluence with Middle Raccoon R. (S9 T78N R29W Dallas Co.) to confluence with Brushy Cr. in S22 T79N R31W Guthrie 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: 2 - Some of the designated uses are met but there is insufficient data to determine if remaining designated uses are met.
Trend: Unknown
Created: 11/1/2023 8:12:28 AM
Updated: 1/25/2024 10:54:22 AM

Use Support

Class A1

Recreation - Primary contact

WINOFI

Bacteria: Indicator Bacteria- E. coli

Support Level

Further Investigation Needed

Impairment Code

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

Cause Magnitude

High

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2008

Impairment Rationale

Geometric mean criterion exceeded

Data Source

TMDL monitoring: Iowa DNR

Class BWW1

Aquatic Life - Warm Water Type 1

Fully Supported

Class HH

Human Health -

Not Assessed

Impairment Delistings

Cycle Added	Class	Cause	Data Source	Rationale
2016	Class BWW1	Fish Kill: Caused By Fertilizer Spill	Biological monitoring: Iowa DNR WQMA	New data: recovery of fish community from pollutant-caused fish kill

Documentation

Assessment Summary

The Class A1 use was assessed as "WINOFI" due to levels of indicator bacteria that violated state water quality criteria. The Class BWW1 use was assessed as "fully 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	181	South Raccoon River	Nations Bridge County Park - Stuart
Iowa DNR	6	BIO	See Below	1266	South Raccoon River	Redfield (REMAP #407)
Iowa DNR	6	BIO	See Below	1297	South Raccoon River	Dale (REMAP #335)
Iowa DNR	6	WQ	CY 2005	11250001	South Raccoon River	Site 32 at Redfield

Class A1 – Indicator Bacteria: 2005

Site ID	Data Source ID	# Samples / # Years	2005 Geometric Mean (4 samples)	Annual Geometric Mean Violation	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
11250001	6	4 / 1	6734	Yes	4	100%	NA	Evaluated	WINOFI

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
1297	8/18/21	279.0	47f	MS	Hess	48	Fair	51	Fail
181	7/29/20	330.3	47f	MS	Hess	53	Fair	51	Pass
1266	7/16/20	374.0	47f	MS	Hess	65	Good	51	Pass

Fish:

Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	Riffle Stream?	FIBI score	FIBI Class	47f FIBI BIT	FIBI Pass/Fail
1297	8/18/21	279.0	47f	MS	NA	45	Fair	36	Pass
181	7/29/20	330.3	47f	MS	NA	54	Good	36	Pass
1266	7/16/20	374.0	47f	MS	NA	27	Fair	36	Fail

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Monitored	Pass (2/3)	Full
Fish	Monitored	Pass (2/3)	Full		Assessment was monitored because it was based on two
Overall	Monitored	Pass	Full	1	or more samples collected in a recent 5-year period.

Class BWW1 – Fishkill Assessment:

The Class BWW1 use assessment based on the 2014 fish kill placed this segment in Category 5b. The fish kill was caused by a “pollutant” or was suspected to be caused by a “pollutant”; therefore, the Class BWW1 use was considered impaired. Because the source of the pollutant was not identified and/or the enforcement actions taken against the responsible party have not been resolved, the Class BWW1 use was placed in Category 5b.

Based on DNR IR methodology, if DNR biological sampling is conducted such that the simple majority of sampling events within a recent five-year period show “full support” of the aquatic life use, the fish kill impairment will be delisted due to existence of “new data” and the assessment will be moved to a non-impairment (“fully supported”) category (IR 1). A simple majority of FIBI scores (2/3) in this segment from 2020 and 2021 passed the 47f FIBI BIT; therefore, the category 5b pollutant caused fish kill was delisted.

Details about the 2014 fish kill can be found here: https://programs.iowadnr.gov/fishkill/Events/874

Class HH – No Data

Monitoring and Methods

Assessment Key Dates

8/18/2021

Biological Monitoring

5/26/2005

Monitoring Start

6/23/2005

Monitoring End

4/11/2014

Fish Kill

7/16/2020

Biological Monitoring

7/9/2020

Biological Monitoring

Methods

140

Incidence of spills and/or fish kills

150

Monitoring data more than 5 years old

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

330

Fish surveys

420

Indicator bacteria monitoring