Mississippi River IA 01-NEM-75

from Lock & Dam 11 at north side of Dubuque (Dubuque Co.) to Lock & Dam 10 at Guttenberg (Clayton 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: 12/30/2021 1:11:59 PM
Updated: 1/27/2022 7:01:07 AM

Use Support

Class A1

Recreation - Primary contact

Fully Supported

Class BWW1

Aquatic Life - Warm Water Type 1

Not Supported

Metals: Aluminum

Support Level

Not Supported

Impairment Code

5* - 303(d)-impaired last cycle; fully supporting this cycle; potential de-listing.

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2006

Impairment Rationale

Violations of acute criterion

Data Source

Ambient monitoring: adjacent state

TMDL Priority

Tier IV

Class HH

Human Health -

Fully Supported

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 use was assessed as "fully supported" based on water quality monitoring data. The Class BWW1 use was assessed as “fully supported” based on water quality monitoring data. The Category 5 impairment for acute violations of the aluminum criteria was moved from 5a to 5* (303d impaired last cycle; fully supported this cycle; potential de-listing). Should the aluminum sample results pass the criteria in the 2024 IR cycle, the Category 5 aluminum impairment will be de-listed. The Class HH use was assessed as "fully supported" based fish tissue sampling data and water quality monitoring data.

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
IEPA	10	WQ	CY 2018-2020	99990018	Mississippi River
Iowa DNR	6	FT	See Below	56	Mississippi River	at Guttenberg
Iowa DNR	6	FT	See Below	144	Mississippi River	downstream of Guttenberg

Class A1 - Indicator Bacteria: No Data

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
99990018	10	9 / 2	6.7	9.2	7.9	1	3	NO	Evaluated	Full

Class BWW1 - Conventional 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
99990018	10	Ammonia	9 / 2	0.05	0.35	0.14	NA	0 / 0	3	NO	Evaluated	Full
99990018	10	Chloride	12 / 3	12.8	23.8	18	NA	0 / 0	4	NO	Monitored	Full
99990018	10	Dissolved Oxygen	8 / 2	6.4	13.9	9.6	0	NA / NA	3	NO	Evaluated	Full
99990018	10	pH	9 / 2	6.7	9.2	7.9	1	NA / NA	3	NO	Evaluated	Full
99990018	10	Sulfate	12 / 3	21.9	90	33.9	0	NA / NA	4	NO	Monitored	Full
99990018	10	Temperature	9 / 2	0	24.3	13	0	NA / NA	3	NO	Evaluated	Full

Class BWW1 - Toxic Parameters:

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Acute / Chronic Violations	>1 Acute / Chronic Violation	Assessment Type	Support Level
99990018	10	Aluminum	12 / 3	2760	561.1	321	1 / 1	NO	Monitored	Full
99990018	10	Arsenic	12 / 3	1.39	0.9	0.96	0 / 0	NO	Monitored	Full
99990018	10	Cadmium	12 / 3	1.5	1.5	1.5	0 / 0	NO	Monitored	Full
99990018	10	Chromium	12 / 3	3.69	1.27	0.59	0 / 0	NO	Monitored	Full
99990018	10	Copper	12 / 3	5	1.9	1.7	0 / 0	NO	Monitored	Full
99990018	10	Lead	12 / 3	2.5	2.3	2.5	0 / 0	NO	Monitored	Full
99990018	10	Nickel	12 / 3	3.39	1.36	1.04	0 / 0	NO	Monitored	Full
99990018	10	Phenols	12 / 3	6.1	4.1	4.5	0 / 0	NO	Monitored	Full
99990018	10	Selenium	12 / 3	2.5	2.2	2.5	0 / 0	NO	Monitored	Full
99990018	10	Silver	12 / 3	1.5	1.5	1.5	0 / 0	NO	Monitored	Full
99990018	10	Zinc	11 / 3	7.3	3.3	2.5	0 / 0	NO	Monitored	Full

Class HH-F - Toxic Parameters:

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Maximum Value	Mean Value	Median Value	Number of Non - Detects	Mean Value > Criterion or MCL	Assessment Type	Support Level
99990018	10	Arsenic	12 / 3	2.28	1.22	1.25	0	NO	Monitored	Full
99990018	10	Cadmium	12 / 3	1.5	1.3	1.5	10	NO	Monitored	Full
99990018	10	Chromium	12 / 3	4.6	1.6	1.2	1	NO	Monitored	Full
99990018	10	Copper	12 / 3	5	1.9	1.7	1	NO	Monitored	Full
99990018	10	Nickel	12 / 3	6.24	2.14	1.76	0	NO	Monitored	Full
99990018	10	Phenols	12 / 3	6.1	4.1	4.5	5	NO	Monitored	Full
99990018	10	Selenium	12 / 3	2.5	2.2	2.5	9	NO	Monitored	Full
99990018	10	Zinc	11 / 3	21.6	8.3	7.3	1	NO	Monitored	Full

Class HH - Fish Tissue Sampling:

Site ID	Biopart	Year	Species	# in sample / # of samples	Avg Length (cm)	(Avg) Hg (ppm)	Chlordane (ppm)	Sum PCBs (ppm)
56	tissue plug	2020	largemouth bass	20	32.7	0.244
56	tissue plug	2020	northern pike	20	60.0	0.19
56	tissue plug	2020	sauger	35	31.1	0.142
56	tissue plug	2020	shovelnose sturgeon	10	49.3	0.056
56	tissue plug	2020	walleye	15	43.6	0.207
56	tissue plug	2020	yellow perch	20	22.3	0.082
144	fillet	2015	common carp	4	54.9	0.15	0.02	0.06
Support Level	Full

Monitoring and Methods

Assessment Key Dates

6/22/2020

Fixed Monitoring Start Date

9/21/2016

Fixed Monitoring End Date

9/18/2015

Fish Tissue Monitoring

7/1/2020

Fish Tissue Monitoring

Methods

230

Fixed station physical/chemical (conventional plus toxic pollutants)

260

Fish tissue analysis

860

Other Agencies/Organizations provided monitoring data