Little Sioux River IA 06-LSR-1577

from confluence with Ocheyedan R. at Spencer (S13 T96N R37W Clay Co.) to confluence with Milford Cr. in NW 1/4 S14 T98N R37W Dickinson 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: Stable
Created: 12/30/2021 11:26:19 AM
Updated: 1/25/2022 3:43:26 PM

Use Support

Class A1

Recreation - Primary contact

Not Supported

Bacteria: Indicator Bacteria- E. coli

Support Level

Not 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 BWW1

Aquatic Life - Warm Water Type 1

Fully Supported

Class HH

Human Health -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 use was assessed as "not supported" due to levels of indicator bacteria that violated state water quality criteria. The Class BWW1 use was assessed as "fully supported" based on biological sampling data, continuous dissolved oxygen monitoring data, and water quality monitoring data. All other designated uses were "not assessed."

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	WQ	CY 2012-2014	10210002	Little Sioux River	US of Spencer (US1)
Iowa DNR	6	BIO	See Below	923	Little Sioux River	Spencer – US1

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
10210002	6	22 / 3	112	144	217	Yes	11	50%	Yes	Evaluated	Not

Class A1 - pH:

Site ID	Data Source ID	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
10210002	6	32 / 3	8.9	8.3	8.3	0	0%	No	Evaluated	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
10210002	6	Ammonia	32 / 3	1.1	0.17	0.05	0 / 0	0% / 0%	No	Evaluated	Full
10210002	6	Chloride	33 / 3	41	28	28	0 / 0	0% / 0%	No	Evaluated	Full
10210002	6	Dissolved oxygen	33 / 3	20	12	12.3	NA / 0	NA / 0%	No	Evaluated	Full
10210002	6	pH	32 / 3	8.9	8.3	8.3	0 / NA	0% / NA	No	Evaluated	Full
10210002	6	Sulfate	33 / 3	150	91	94	0 / NA	0% / NA	No	Evaluated	Full
10210002	6	Temperature	33 / 3	29.7	11.7	12.3	0 / 0	0% / 0%	No	Evaluated	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	47a BMIBI BIT	BMIBI Pass/ Fail
923	9/13/16	536	47a	MO/WW	Hess	70	Good	54	Pass
923	8/2/16	536	47a	MO/WW	Float ArtSub	70	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
923	9/13/16	536	47a	MO/WW	NA	51	Good	43	Pass

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Pass (2/2)	Full
Fish	Evaluated	Pass (1/1)	Full
Overall	Evaluated	Pass	Full	1	Assessment was evaluated because the drainage area of the sample site was larger than the calibrated range.

Class BWW1- Continuous DO Monitoring:

Site ID	Data Source ID	# Days Monitoring (2016/2017/2018/ 2019/2020)	DO Criteria Type	# 2016 violations / Violations needed for impairment	# 2017 violations / Violations needed for impairment	# 2018 violations / Violations needed for impairment	# 2019 violations / Violations needed for impairment	# 2020 violations / Violations needed for impairment	Violates Annual Significantly >10% Rule?	Assessment Type	Support Level
			24 hr	5/11	NA	NA	NA	NA	No
923	6	70/0/0/0/0	16 hr	0/11	NA	NA	NA	NA	No	Evaluated	Full

Class HH - No Data

Monitoring and Methods

Assessment Key Dates

1/1/2012

Fixed Monitoring Start Date

9/8/2014

Fixed Monitoring End Date

8/2/2016

Biological Monitoring

9/13/2016

Biological Monitoring

Methods

150

Monitoring data more than 5 years old

210

Fixed station physical/chemical monitoring (conventional pollutants 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