Des Moines River IA 04-LDM-1020

upper end of Red Rock Reservoir (W line S34 T77N R20W Marion Co.) to confluence with South R. in S12 T77N R22W Warren 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
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Cycle: 2020
Release Status: Final
Overall IR: 4 - Water is impaired or threatened and a TMDL has been completed or is not needed.
Trend: Unknown
Created: 9/11/2020 6:14:55 AM
Updated: 10/13/2020 6:45:02 AM

Use Support

Class A1

Recreation - Primary contact

Partially Supported

Bacteria: Indicator Bacteria- E. coli

Support Level

Partially Supported

Impairment Code

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

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

Class BWW1

Aquatic Life - Warm Water Type 1

WINOFI

Biological: low aquatic macroinvertebrate IBI

Support Level

Further Investigation Needed

Impairment Code

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

Cause Magnitude

Moderate

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2014

Impairment Rationale

Low Biotic Index

Data Source

Biological monitoring: Iowa DNR WQMA

Class HH

Human Health -

Not Assessed

General Use

General Use water -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 use was assessed as "partially supported" due to levels of indicator bacteria (E. coli) that exceeded state water quality standards. The Class BWW1 aquatic life use remains assessed as "partially supported" based on biological sampling data. All other designated uses were "not assessed". Note: A TMDL for bacteria was approved by U.S. EPA in March 2010. Because this TMDL covers all the identified impairments in this segment, this segment was moved to IR Category 4a (TMDL approved).

Assessment Explanation

Sources of Data:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
USACE	12	WQ	CY 2016-2018	17770003	Des Moines River at S35
Iowa DNR	6	BIO	See Below	918	Des Moines River	Des Moines – DS1

Class A1 - Indicator Bacteria:

Site ID	Data Source ID	# Samples / # Years	2016 Geometric Mean	2017 Geometric Mean	2018 Geometric Mean	Annual Geometric Mean Violation	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
17770003	12	34 / 3	162.48	112.45	148.47	Yes	11	32%	Yes	Monitored	Partial

Class A - pH:

Site ID	Data Source ID	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
17770003	12	65 / 3	8.895	8.24	8.25	0	0%	No	Monitored	Full

Class BWW1 - Conventional 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
17770003	12	Ammonia	65 / 3	1.22	0.08	0.02	0 / 0	0% / 0%	No	Monitored	Full
17770003	12	Dissolved oxygen	65 / 3	16.7	10.6	10.4	NA / 0	NA / 0%	No	Monitored	Full
17770003	12	pH	65 / 3	8.895	8.24	8.25	0 / NA	0% / NA	No	Monitored	Full
17770003	12	Temperature	65 / 3	28.8	16.6	18.5	0 / 0	0% / 0%	No	Monitored	Full

Class BWW1 - Biological Sampling:

Benthic Macroinvertebrates:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage/Thermal	BM Sample Gear	BMIBI score	BMIBI Class	47f BMIBI BIT	BMIBI Pass/ Fail
918	9/24/13	11655	47f	MS/WW	ArtSub	34	Fair	51	Fail
918	8/27/12	11655	47f	MS/WW	Anchored ArtSub	13	Poor	51	Fail

Overall:

Community	Assessment Type	Assessment Result	Support Level	Earned IR Category	Actual IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Fail (0/2)	Partial	3bu	3bu	Assessment is evaluated because it included samples not collected in the last five years and the drainage area of the samples site was larger than the calibrated range.

Class HH - No Data

Monitoring and Methods

Assessment Key Dates

8/27/2012

Biological Monitoring

9/24/2013

Biological Monitoring

1/4/2016

Fixed Monitoring Start Date

12/3/2018

Fixed Monitoring End Date

3/1/2010

TMDL Completed

Methods

150

Monitoring data more than 5 years old

210

Fixed station physical/chemical monitoring (conventional pollutants only)

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

420

Indicator bacteria monitoring