Dry Creek IA 06-BSR-1878

mouth (T94N R48W Sec4 Sioux Co.) to headwaters (T97N R45W Sec32) Sioux 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
View assessment methodology in new window

Cycle: 2022
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown
Created: 1/3/2022 9:47:32 AM
Updated: 1/10/2022 9:58:16 AM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Assessed

Class BWW1

Presumptive Use

Aquatic Life - Warm Water Type 1

Not Supported

Biological: low fish & invert IBIs- cause unknown

Support Level

Not 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

Fish Kill: Due To Natural Causes

Support Level

Not Supported

Impairment Code

5b - Biological impairment or pollutant-caused fish kill - unknown source. No administrative action.

Cause Magnitude

Moderate

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2006

Impairment Rationale

Non Pollutant-caused fish kill

Data Source

Fish kill investigation: Iowa DNR

TMDL Priority

Tier IV

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class BWW1 use was assessed as “not supported” based on biological sampling data and due to a fish kill investigation. The apparent lack of fish in this segment, as documented by the 2004-2006 biological sampling data, continues to suggest a severe water quality impact and overwhelming evidence of impairment that justifies keeping this segment on Iowa’s Section 303(d) list. 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	BIO	See Below	393	Dry Creek	Hawarden – REMAP #103
Iowa DNR	6	BIO	See Below	470	Dry Creek	Sioux Center – REMAP #144
Iowa DNR	6	BIO	See Below	612	Dry Creek	Hawarden – REMAP #219

Presumptive Class A1 - No Data

Presumptive Class BWW1 - Biological Sampling:

Benthic Macroinvertebrates:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	BM Sample Gear	BMIBI score	BMIBI Class	47a BMIBI BIT	BMIBI Pass/Fail
612	7/12/06	40	47a	MO	Hess	42	Fair	54	Fail
470	7/5/05	9	47a	MO	Hess	40	Fair	54	Fail
393	6/28/04	36	47a	MO	Hess	28	Poor	54	Fail

Fish:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	Riffle Stream?	FIBI score	FIBI Class	47a FIBI BIT	FIBI Pass/Fail
612	7/12/06	40	47a	MO	NA	0	Poor	43	Fail
470	7/5/05	9	47a	MO	NA	0	Poor	43	Fail
393	6/28/04	36	47a	MO	NA	0	Poor	43	Fail

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Fail (0/3)	Not
Fish	Evaluated	Fail (0/3)	Not		Assessment was evaluated because the drainage areas of the sample sites
Overall	Evaluated	Fail	Not	5bt	were smaller than the calibrated range.

Presumptive Class BWW1 – Fish kill Assessment:

The presumptive Class BWW1 aquatic life use assessment based on the 2003 fish kill placed this segment in Category 5b. The fish kill was caused by a “pollutant”or was suspected to be caused by a “pollutant”; therefore, the presumptive Class BWW1 use was considered impaired. Because the source of the pollutant wasnot identified and/or the enforcement actions taken against the responsible party have not been resolved, the presumptive Class BWW1 use was placed inCategory 5b. Due to uncertainty regarding the recovery of the aquatic life following the fish kill, any existing fish kill 5b impairment will remain in Category 5buntil more recent sampling has shown recovery of the aquatic community or the responsible party has paid restitution.

More details about the 2003 fish kill can be found here: https://programs.iowadnr.gov/fishkill/Events/573

Monitoring and Methods

Assessment Key Dates

7/12/2006

Biological Monitoring

7/5/2005

Biological Monitoring

6/28/2004

Biological Monitoring

9/13/2003

Fish Kill

Methods

120

Surveys of fish and game biologists/other professionals

140

Incidence of spills and/or fish kills

150

Monitoring data more than 5 years old

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

330

Fish surveys