Ocheyedan River IA 06-LSR-1638

mouth (S13 T96N R37W Clay Co.) to confluence with Little Ocheyedan R. in S28 T98N R39W Osceola 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: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Stable
Created: 9/22/2020 12:30:25 PM
Updated: 10/16/2020 3:17:50 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

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2008

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Ambient monitoring: Iowa DNR-rivers

TMDL Priority

Tier III

Class BWW2

Aquatic Life - Warm Water Type 2

WINOFI

Biological: low fish & invert IBIs- cause unknown

Support Level

Further Investigation Needed

Impairment Code

3b-c - Use potentially biologically impaired based on calibrated IBI metrics.

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2006

Impairment Rationale

Low Biotic Index

Data Source

Biological monitoring: Iowa DNR WQMA

General Use

General Use water -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 primary contact recreation use remains assessed as "partially supported" due to 2012-2014 levels of indicator bacteria that violated state water quality criteria. The Class BWW2 aquatic life use remains assessed as "partially supported" based on 2003, 2012, and 2013 biological sampling data. 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	WQ	CY 2012-2014	10210001	Ocheyedan River near Spencer (US2)
Iowa DNR	6	BIO	See Below	354	Ocheyedan River	Spencer – REMAP #59
Iowa DNR	6	BIO	See Below	929	Ocheyedan River	Spencer - US2

Class A1 - Indicator Bacteria:

Site ID	Data Source ID	# Samples / # Years	2012 Geometric Mean	2013 Geometric Mean	2014 Geometric Mean	Annual Geometric Mean Violation	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
10210001	6	22 / 3	149	264	209	Yes	10	45%	Yes	Evaluated	Partial

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
10210001	6	Ammonia	32 / 3	1.7	0.15	0.05	0 / 0	0% / 0%	No	Evaluated	Full
10210001	6	Chloride	33 / 3	38	26	25	0 / 0	0% / 0%	No	Evaluated	Full
10210001	6	Dissolved oxygen	33 / 3	17.1	11.2	11.4	NA / 0	NA / 0%	No	Evaluated	Full
10210001	6	pH	32 / 3	8.6	8.1	8.1	0 / NA	0% / NA	No	Evaluated	Full
10210001	6	Sulfate	33 / 3	300	137	120	0 / NA	0% / NA	No	Evaluated	Full
10210001	6	Temperature	33 / 3	27.9	11.7	13	0 / 0	0% / 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	47a BMIBI BIT	BMIBI Pass/ Fail
929	10/8/13	426	47a	MO/WW	ArtSub	45	Fair	54	Fail
929	8/14/12	426	47a	MO/WW	ArtSub	61	Good	54	Pass

Fish:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage/ Thermal	Riffle Stream?	FIBI score	FIBI Class	47a FIBI BIT	FIBI Pass/ Fail
354	7/24/03	409	47a	MO/WW	NA	28	Fair	43	Fail

Overall:

Community	Assessment Type	Assessment Result	Support Level	Earned IR Category	Actual IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Fail (1/2)	Partial
Fish	Evaluated	Fail (0/1)	Partial
Overall	Evaluated	Fail	Partial	3bc	3bc	Assessment is evaluated because it included samples not collected in the last five years.

Monitoring and Methods

Assessment Key Dates

1/9/2012

Fixed Monitoring Start Date

9/8/2014

Fixed Monitoring End Date

7/24/2003

Biological Monitoring

8/14/2012

Biological Monitoring

10/8/2013

Biological Monitoring

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

330

Fish surveys

420

Indicator bacteria monitoring