Middle Fork Grand River IA 05-GRA-1378

IA/MO line to trib S13T68NR30W Ringgold

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: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown
Created: 9/17/2020 10:25:26 AM
Updated: 10/19/2020 6:57:58 AM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Supported

Bacteria: Indicator Bacteria- E. coli

Support Level

Not Supported

Impairment Code

5p - Impairment occurs on a waterbody with a presumptive A1 or B(WW1) use.

Cause Magnitude

Moderate

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2014

Impairment Rationale

Geometric mean criterion exceeded

Data Source

TMDL monitoring: Iowa DNR

TMDL Priority

Tier III

Class BWW2

Aquatic Life - Warm Water Type 2

Partially Supported

Biological: low fish & invert IBIs- cause unknown

Support Level

Partially Supported

Impairment Code

5b-t - Biological - tentative

Cause Magnitude

Moderate

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2006

Impairment Rationale

Low Biotic Index

Data Source

Biological monitoring: Iowa DNR WQMA

TMDL Priority

Tier IV

Temperature: Thermal Modifications

Support Level

Further Investigation Needed

Impairment Code

3b - Use potentially impaired based on an evaluated assessment.

Cause Magnitude

Moderate

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2016

Impairment Rationale

Significantly > 10% of samples fail to meet criterion

Data Source

Ambient monitoring: Iowa DNR-continuous

General Use

General Use water -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class A1 use remains assessed as “not supported” due to violations of state water quality criteria for indicator bacteria (E. coli). The Class BWW2 use remains assessed as “partially supported” based on biological sampling data and on continuous dissolved oxygen and temperature monitoring data.

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	397	Middle Fork Grand River	Mt. Ayr – REMAP #114
Iowa DNR	6	BIO	See Below	864	Middle Fork Grand River	Mount Ayr – MFGR1
Iowa DNR	6	BIO	See Below	865	Middle Fork Grand River	Mount Ayr – MFGR2
Iowa DNR	6	WQ	CY 2011	11800001	Middle Fork Grand River	Mount Ayr – MFGR1
Iowa DNR	6	WQ	CY 2011	11800002	Middle Fork Grand River	Mount Ayr – MFGR2
Iowa DNR	6	WQ	CY 2011	16800002	Middle Fork Grand River	Mt. Ayr – REMAP #114

Presumptive Class A1 - Indicator Bacteria:

Site ID	Data Source ID	# Samples / # Years	2011 Geometric Mean	Annual Geometric Mean Violation	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
16800002	6	12 / 1	1435	Yes	12	100%	Yes	Evaluated	Not
11800001	6	12 / 1	1085	Yes	12	100%	Yes	Evaluated	Not
11800002	6	12 / 1	956	Yes	12	100%	Yes	Evaluated	Partial

Presumptive 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
16800002	11	15 / 1	8.8	8.3	8.2	0	0%	No	Evaluated	Full
11800001	11	19 / 1	8.4	8	8.1	0	0%	No	Evaluated	Full
11800002	11	15 / 1	8.6	8.2	8.1	0	0%	No	Evaluated	Full

Class BWW2 - 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
16800002	11	Ammonia	15 / 1	0.12	0.06	0.05	0 / 0	0% / 0%	No	Evaluated	Full
11800001	11	Ammonia	15 / 1	0.1	0.06	0.05	0 / 0	0% / 0%	No	Evaluated	Full
11800002	11	Ammonia	15 / 1	0.07	0.06	0.05	0 / 0	0% / 0%	No	Evaluated	Full
16800002	11	Chloride	15 / 1	97	62	54	0 / 0	0% / 0%	No	Evaluated	Full
11800001	11	Chloride	23 / 1	54	25	21	0 / 0	0% / 0%	No	Evaluated	Full
11800002	11	Chloride	15 / 1	76	38	31	0 / 0	0% / 0%	No	Evaluated	Full
16800002	11	Dissolved oxygen	15 / 1	13.8	10.9	10.2	NA / 0	NA / 0%	No	Evaluated	Full
11800001	11	Dissolved oxygen	19 / 1	12.8	9.8	9.7	NA / 0	NA / 0%	No	Evaluated	Full
11800002	11	Dissolved oxygen	15 / 1	15.2	10.2	9.9	NA / 0	NA / 0%	No	Evaluated	Full
16800002	11	pH	15 / 1	8.8	8.3	8.2	0 / NA	0% / NA	No	Evaluated	Full
11800001	11	pH	19 / 1	8.4	8	8.1	0 / NA	0% / NA	No	Evaluated	Full
11800002	11	pH	15 / 1	8.6	8.2	8.1	0 / NA	0% / NA	No	Evaluated	Full
16800002	11	Sulfate	15 / 1	34	28	28	0 / NA	0% / NA	No	Evaluated	Full
11800001	11	Sulfate	23 / 1	27	19	21	0 / NA	0% / NA	No	Evaluated	Full
11800002	11	Sulfate	15 / 1	33	24	23	0 / NA	0% / NA	No	Evaluated	Full
16800002	11	Temperature	15 / 1	33.2	19.3	18.9	1 / 0	7% / 0%	No	Evaluated	Full
11800001	11	Temperature	19 / 1	29.5	16.8	12.5	0 / 0	0% / 0%	No	Evaluated	Full
11800002	11	Temperature	15 / 1	34.9	20.3	17.1	2 / 0	13% / 0%	No	Evaluated	Full

Class BWW2 - Biological Sampling:

Benthic Macroinvertebrates:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage/Thermal	BM Sample Gear	BMIBI score	BMIBI Class	40a BMIBI BIT	BMIBI Pass/ Fail
865	8/24/11	29	40a	MO/WW	LowFlow ArtSub	35	Fair	41	Fail
397	9/9/10	9	40a	MO/WW	ArtSub	32	Fair	41	Fail

Fish:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage/Thermal	Riffle Stream?	FIBI score	FIBI Class	40a FIBI BIT	FIBI Pass/ Fail
397	8/25/11	9	40a	MO/WW	NA	20	Poor	33	Fail
864	8/24/11	42	40a	MO/WW	NA	15	Poor	33	Fail
865	8/24/11	29	40a	MO/WW	NA	10	Poor	33	Fail
397	9/8/10	9	40a	MO/WW	NA	27	Fair	33	Fail

Overall:

Community	Assessment Type	Assessment Result	Support Level	Earned IR Category	Actual IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Fail (0/2)	Partial
Fish	Evaluated	Fail (0/4)	Partial
Overall	Evaluated	Fail	Partial	3bc	5bt	Assessment is evaluated because it used samples that were not collected in the last five years.

Class BWW2 – Continuous Monitoring:

The results of continuous dissolved oxygen (DO) and temperature monitoring suggest impaired water quality conditions. The lowest DO concentration recorded in 81 days of continuous monitoring was 3.8 mg/L. The daily DO minimum concentration failed to meet the 24-hour DO criterion (4 mg/L) and the 16-hour DO criterion (5 mg/L) in 2 of 81 days each. The percentages exceeding the 24-hour and 16-hour DO criteria (2.5%) were less than (passing) the 10% impairment threshold used to assess conventional water quality parameters. The associated statistical analysis confidence level for the 24-hour analysis result was high (>90%). The maximum stream temperature recorded during the sensor deployment period was 39.8 degrees (C). The temperature criterion for warmwater interior streams (32 C) was exceeded in 52 of 81 days. The percentage exceeding (64.2%) was greater than (failing) the 10% impairment threshold with high statistical confidence (>90%). Based on these data, the BWW2 aquatic life use is assessed as impaired for stream temperature. The assessment type is “evaluated” because it is based on data collected from a single year within the current data assessment period. In order to meet the requirements for a “monitored” assessment, the DNR’s continuous monitoring assessment methodology requires monitoring data from two or more years within the assessment period.

Monitoring and Methods

Assessment Key Dates

9/8/2010

Biological Monitoring

8/24/2011

Biological Monitoring

8/25/2011

Biological Monitoring

3/30/2011

Non-fixed Monitoring Start Date

10/25/2011

Non-fixed Monitoring End Date

Methods

150

Monitoring data more than 5 years old

220

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

222

Non-fixed-station monitoring (conventional during key seasons and flows)

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

330

Fish surveys

420

Indicator bacteria monitoring