Des Moines River IA 04-UDM-1223

from confluence with Pilot Cr. near Bradgate (S1 T92N R31W Pocahontas Co.) to confluence with Cylinder Cr. in NW 1/4 S28 T94N R31W Palo Alto 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
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Cycle: 2022
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown
Created: 12/28/2021 3:35:19 PM
Updated: 1/13/2022 1:34:24 PM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Assessed

Class BWW1

Aquatic Life - Warm Water Type 1

WINOFI

Biological: low fish & invert IBIs- cause unknown

Support Level

Further Investigation Needed

Impairment Code

3b-u - Use potentially biologically impaired based on uncalibrated IBI metrics.

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2008

Impairment Rationale

Low Biotic Index

Data Source

Biological monitoring: Iowa DNR WQMA

Class HH

Human Health -

Not Supported

Fish Consumption Advisory: Mercury

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

2014

Impairment Rationale

Fish consumption advisory in effect: no more than 1 meal/week

Data Source

Fish contaminant monitoring: Iowa DNR

TMDL Priority

Tier IV

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class BWW1 use was assessed as "WINOFI" based on biological sampling data. The Class HH (fish consumption) use remains assessed as “not supported” due to the existence of a one meal per week mercury fish consumption advisory in this segment. 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	509	West Fork Des Moines River	West Bend – REMAP #177

Class A1 - No Data

Class BWW1 - Biological Sampling:

Benthic Macroinvertebrates:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage/Thermal	BM Sample Gear	BMIBI score	BMIBI Class	47b BMIBI BIT	BMIBI Pass/ Fail
509	8/17/05	1956	47b	MS/WW	ArtSub	53	Fair	62	Fail

Fish:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage/Thermal	Riffle Stream?	FIBI score	FIBI Class	47b FIBI BIT	FIBI Pass/Fail
509	8/17/05	1956	47b	MS/WW	Undetermined	23	Poor	32	Fail

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Fail (0/1)	Not
Fish	Evaluated	Fail (0/1)	Not		Assessment was evaluated because the drainage area of the
Overall	Evaluated	Fail	WINOFI	3bu	sampling site was greater than the calibrated range.

Class HH - Fish Tissue Sampling:

Support Level

Not

A one meal/week mercury consumption advisory for any predator fish exists on this segment. Based on IR Methodology, the Class HH (fish consumption) use was assessed as “not supported.”

Monitoring and Methods

Assessment Key Dates

8/17/2005

Biological Monitoring

Methods

150

Monitoring data more than 5 years old

260

Fish tissue analysis

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

330

Fish surveys