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 2016 - 2018
Stream/River Water Quality Data	CY 2016 - 2018
Lake Water Quality Data	CY 2014 - 2018
Biological Sampling Data	CY 2014 - 2018*
Fish Kill Data	CY 2014 - 2018
Fish Tissue Sampling Data	CY 2014 - 2018
Continuous Dissolved Oxygen Sampling Data	CY 2014 - 2018
*Biological sites sampled in both 2013 and 2017 were also assessed.

Open Segment Map
View assessment methodology in new window

Cycle: 2020
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown
Created: 9/15/2020 10:15:16 AM
Updated: 10/14/2020 1:54:03 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 -

Partially Supported

Fish Consumption Advisory: Mercury

Support Level

Partially 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

General Use

General Use water -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class BWW1 use remains assessed as "partially supported" based on biological sampling data. The Class HH use remains assessed as "partially supported" based on fish tissue sampling data and due to the existence of a one meal per week mercury fish consumption advisory. All other designated uses were "not assessed".

Assessment Explanation

Sources of Data:

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
Iowa DNR	6	FT	See Below	136	West Fork Des Moines River	SE of Bradgate
Iowa DNR	6	FT	See Below	276	West Fork Des Moines River	Gotch Park - Humboldt

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	Und	23	Poor	32	Fail

Overall:

Community	Assessment Type	Assessment Result	Support Level	Earned IR Category	Actual IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Fail (0/1)	Partial
Fish	Evaluated	Fail (0/1)	Not
Overall	Evaluated	Fail	Partial	3bu	3bu	Assessment is evaluated because it included samples not collected in the last five years and the drainage areas of the sites were larger than the calibrated range.

Class HH – Fish Tissue Sampling:

Seg ID	Site ID	Date	Species Name	Biopart	# in sample	Hg result	Hg violation (>0.3)?	Assessment Type	Support Level
1220	276	8/2/2011	walleye	plug	3	0.143	No	Evaluated	Full
1222	136	8/24/2010	walleye	fillet	3	0.37	Yes	Evaluated	Partial
1222	136	9/4/2009	walleye	fillet	5	0.328	Yes	Evaluated	Partial
A one meal/week consumption advisory for mercury exists on this segment of the West Fork Des Moines River – see Iowa Consumption Advisories The existence of a mercury consumption advisory for this segment of the West Fork Des Moines River indicates that the fish consumption use should be assessed as “partially supporting”.

Monitoring and Methods

Assessment Key Dates

8/17/2005

Biological Monitoring

9/4/2009

Fish Tissue Monitoring

8/24/2010

Fish Tissue Monitoring

8/2/2011

Fish Tissue 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