Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Dry Creek IA 06-BSR-1878

mouth (T94N R48W Sec4 Sioux Co.) to headwaters (T97N R45W Sec32) Sioux Co.

Cycle
2024
Release Status
Final
Overall IR
5 - Water is impaired or threatened and a TMDL is needed.
Trend
Unknown
Created
12/8/2023 1:33:32 PM
Updated
1/24/2024 11:21:30 AM
Use Support
Class A1
Recreation - Primary contact
Not Assessed
Class BWW1
Aquatic Life - Warm Water Type 1
Not Supported
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
Impairment Code
3b - Use potentially impaired based on an evaluated assessment.
Cause Magnitude
Slight
Status
New
Source
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
2024
Impairment Rationale
Significantly > 10% of days fail to meet 24-hour criteria
Data Source
Ambient monitoring: Iowa DNR-continuous
Impairment Delistings
Cycle Added Class Cause Data Source Rationale
2006 Class BWW1 Fish Kill: Due To Natural Causes Biological monitoring: Iowa DNR fish kill follow-up New data: recovery of fish community from pollutant-caused fish kill
Documentation
Assessment Summary

The presumptive Class BWW1 use was assessed as “not supported” based on biological sampling data. The apparent lack of fish in portions of this segment, as documented by the 2004-2006 biological sampling data, continues to suggest a severe water quality impact impairment that justifies keeping this segment on Iowa’s Section 303(d) list. However the downstream portion of the segment (downstream of the fish kill event) showed overwhelming amount of recent evidence of fish community recovery, therefore delisting the fish kill for this segment. 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

WQ

2021

393

Dry Creek

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

Overall

Evaluated

Fail

Not

5bt

the sample sites were smaller than the calibrated range.


Presumptive Class BWW1 – Fish kill Assessment:

BioNet Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage/ Thermal

Fish per mile

47a REMAP 25 % fish per mile

>47a REMAP 25 % fish per mile?

2024 IR 47a expected fish taxa

Fish Taxa Present % (>50% to pass)

1401

10/10/22

49.9

47a

MO/WW

6864

496

Yes (Pass)

7/10

70% (Pass)

The presumptive Class BWW1 use previously resided in Category 5b based on a fish kill that occurred in 2003. This segment’s fish community was sampled in 2022 as part of the DNR fish kill follow-up sampling program. The results from this follow-up sampling and comparison to ecoregion averages suggest that the fish community of this segment is similar to non-fish kill impacted streams. Based on the fish kill follow-up sampling results, the Category for the fish kill assessment was changed from 5b to 3a (not assessed).

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

Presumptive Class BWW1- Continuous DO Monitoring:

Site ID

Data Source ID

# Days Monitoring (2021)

DO Criteria Type

# 2021 violations / Violations needed for impairment

Violates Annual Significantly >10% Rule?

Assessment Type

Support Level

24 hr

6/4

Yes

393

6

15

16 hr

3/4

No

Evaluated

WINOFI



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
10/10/2022
Biological Monitoring
6/28/2021
Monitoring Start
7/12/2021
Monitoring End
Methods
140
Incidence of spills and/or fish kills
150
Monitoring data more than 5 years old
200
Physical/Chemical Monitoring
315
Regional reference site approach
320
Benthic macroinvertebrate surveys
330
Fish surveys