Missouri River IA 06-WEM-1722

from confluence with Omaha Creek Ditch (SW 1/4 S6 T86N R47W Woodbury Co. at river mile 715.8 (near Browns Lake)) to confluence with Big Sioux R. at river mile 734.0 at Sioux City Woodbury 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.

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Cycle: 2020
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown
Created: 10/7/2020 8:21:15 AM
Updated: 10/16/2020 12:53:17 PM

Use Support

Class A1

Recreation - Primary contact

Partially Supported

Bacteria: Indicator Bacteria- E. coli

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

2016

Impairment Rationale

Listing by adjacent state

Data Source

Ambient monitoring: adjacent state

TMDL Priority

Tier III

Class BWW1

Aquatic Life - Warm Water Type 1

Partially Supported

Flow Alteration: Hydrologic Modification

Support Level

Partially Supported

Impairment Code

4c - Non-pollutant caused impairment. No TMDL needed.

Cause Magnitude

Moderate

Status

Continuing

Source

Hydromodification: Dam Release

Source Confidence

Moderate

Cycle Added

1992

Impairment Rationale

Adverse impacts on plant/animal communities

Data Source

Special project/study

Habitat Alterations: Channel Modifications

Support Level

Partially Supported

Impairment Code

4c - Non-pollutant caused impairment. No TMDL needed.

Cause Magnitude

Moderate

Status

Continuing

Source

Hydromodification: Habitat Modification

Source Confidence

Moderate

Cycle Added

1992

Impairment Rationale

Adverse impacts on plant/animal communities

Data Source

Special project/study

Class HH

Human Health -

Fully Supported

General Use

General Use water -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 use remains assessed as "partially supported" based on the bacteria impairment of recreational use identified by the Nebraska Department of Environmental Quality. The Class BWW1 use remains assessed as "partially supported" based on information from local fisheries biologists on impacts related to flow modification and habitat alterations in this segment of the Missouri River. The Class HH use remains assessed as "fully supported" based on fish tissue sampling data.

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	FT	See Below	150	Missouri River W of Sergeant Bluff
USGS	11	WQ	CY 2010-2012	06486000	Missouri River at Sioux City, IA

Class A1:

The Class A1 primary contact recreation use remains assessed as "partially supported" based on the bacteria impairment identified for this assessment segment by the state of Nebraska. A TMDL for the Nebraska impairment in this segment of the Missouri River was approved by EPA in 2007. Because Iowa DNR did not participate in the preparation of this TMDL, this impairment is appropriate for Category 5a of Iowa's Integrated Report.

Class BWW1:

The Class BWW1 aquatic life use remains assessed as "partially supported" (IR Category 4c, non-pollutant stressor) based on the assessment developed for the 1998, 2000, and 2002 reports (i.e., habitat alterations and flow modifications that resulted from development of the river for navigation uses in the mid-Twentieth Century). This assessment was developed in consultation with the Missouri River fisheries biologist for the state of Nebraska.

Class BWW1 - Conventional Parameters: Historical

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
06486000	11	Dissolved oxygen	13 / 2	9.5	8.3	8.3	NA / 0	NA / 0%	No	Evaluated	Full
06486000	11	pH	14 / 2	8.5	8.2	8.2	0 / NA	0% / NA	No	Evaluated	Full
06486000	11	Temperature	230 / 3	30.7	16.2	18	0 / 0	0% / 0%	No	Evaluated	Full

Class HH – Fish Tissue Sampling:

Site ID

Date

Species Name

Biopart

# in sample

chlordane result

chlordane violation (>0.6)?

PCBs result

PCBs violation (>0.2)?

Hg result

Hg violation (>0.3)?

Assessment Type

Support Level

150

8/4/15

flathead catfish

plug

0.080

Monitored

Full

150

8/29/13

channel catfish

fillet

<0.2

<0.6

0.11

Evaluated

Full

150

8/8/13

flathead catfish

plug

0.301

Yes

Evaluated

Partial

Monitoring and Methods

Assessment Key Dates

1/21/2010

Non-fixed Monitoring Start Date

12/17/2012

Non-fixed Monitoring End Date

8/8/2013

Fish Tissue Monitoring

8/29/2013

Fish Tissue Monitoring

8/4/2015

Fish Tissue Monitoring

Methods

120

Surveys of fish and game biologists/other professionals

150

Monitoring data more than 5 years old

220

Non-fixed station physical/chemical monitoring (conventional pollutant only)

260

Fish tissue analysis

860

Other Agencies/Organizations provided monitoring data