Middle Fork South Beaver Creek IA 02-CED-563

mouth (N 1/2 S28 T89N R17W Grundy Co.) confluence with unnamed tributary in NE 1/4 S28 T89N R18W Grundy Co. (upstream from Grundy Co.Rd. T13).

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: 4 - Water is impaired or threatened and a TMDL has been completed or is not needed.
Trend: Unknown
Created: 11/1/2023 8:12:25 AM
Updated: 2/1/2024 7:38:59 AM

Use Support

Class A1

Presumptive Use

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

Moderate

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2022

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Watershed project monitoring

Class BWW1

Presumptive Use

Aquatic Life - Warm Water Type 1

Not Supported

Biological: low Biological Integrity

Support Level

Not Supported

Impairment Code

4a - Pollutant-caused impairment. TMDL has been completed.

Cause Magnitude

Moderate

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

1998

Impairment Rationale

Adverse impacts on plant/animal communities

Data Source

Biological monitoring: Iowa DNR WQMA

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class A1 use was assessed as “WINOFI” due to violations of Iowa water quality criteria for indicator bacteria (E. coli). The presumptive Class BWW1 use was assessed as "not supported" based on biological sampling data. Note: A TMDL for sediment and phosphorus impacts was prepared by DNR and approved by EPA in October 2007. Because all Category 5 impairments identified for this segment were addressed by the TMDL, this segment was placed in (and remains in) Category 4a of Iowa's Integrated Report.

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	259	Middle Fork South Beaver Creek	Wellsburg (REMAP #45)
CRWQ	23	WQ	CY 2020-2022	99990079	Middle Fork South Beaver Creek

Presumptive Class A1 - Indicator Bacteria:

Site ID

Data Source ID

# Samples per Year (2020/ 2021/2022)

2020 Geometric Mean

2021 Geometric Mean

2022 Geometric Mean

Violates Annual Geometric Mean?

# 2020 SSM violations / SSM Violations needed for impairment

# 2021 SSM violations / SSM Violations needed for impairment

# 2022 SSM violations / SSM Violations needed for impairment

Violates Annual SSM Significantly >10% Rule?

Assessment Type

Support Level

99990079

5/5/5

383

265

228

YES

4 / NA

Eval

WINOFI

Presumptive Class A1 - 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
99990079	23	13 / 3	6.11	8.37	7.9	1	4	NO	Mon	Full

Presumptive Class BWW1 - Binomial 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
99990079	23	Chloride	15 / 3	14.9	48.5	22.5	NA	0 / 0	4	NO	Mon	Full
99990079	23	Dissolved Oxygen	12 / 3	6.4	11.9	8.5	0	NA / NA	4	NO	Mon	Full
99990079	23	pH	13 / 3	6.11	8.37	7.9	1	NA / NA	4	NO	Mon	Full
99990079	23	Sulfate	15 / 3	16.1	37.1	25.7	0	NA / NA	4	NO	Mon	Full
99990079	23	Temperature	15 / 3	2.8	23.7	16.5	0	NA / NA	4	NO	Mon	Full

Presumptive Class BWW1 – Biological Sampling

Benthic Macroinvertebrates:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	BM Sample Gear	BMIBI score	BMIBI Class	47c BMIBI BIT	BMIBI Pass/Fail
259	8/14/01	22	47c	MS	Art Sub	35	Fair	52	Fail

Fish:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	Riffle Stream?	FIBI score	FIBI Class	47c FIBI BIT	FIBI Pass/Fail
259	8/14/01	22	47c	MS	No	64	Good	44	Pass

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Fail (0/1)	Not
Fish	Evaluated	Pass (1/1)	Full
Overall	Evaluated	Fail	Not	4a	Assessment was evaluated because it was based on a single sample.

Monitoring and Methods

Assessment Key Dates

6/2/2020

Monitoring Start

8/14/2001

Biological Monitoring

8/23/2022

Monitoring End

10/1/2007

TMDL Completed

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

860

Other Agencies/Organizations provided monitoring data