Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

McLoud Run IA 02-CED-508

Alternate name(s) for this segment: Cold Stream

mouth (SW 1/4 S16 T83N R7W Linn Co.) to headwaters in SW 1/4 S5 T83N R7W Linn Co.

This is a DRAFT assessment
Draft assessments may change without notice
Cycle
2026
Current Phase
Public Comment
Overall IR
5 - Water is impaired or threatened and a TMDL is needed.
Trend
Declining
Trend Comment
Continued fish kills.
Created
10/27/2025 3:09:33 PM
Updated
12/19/2025 8:30:56 AM
Use Support
Class A1
Recreation - Primary contact
Not Supported
Support Level
Not Supported
Impairment Code
5p - Impairment occurs on a waterbody with a presumptive A1 or B(WW1) use.
Cause Magnitude
High
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
2014
Impairment Rationale
Geometric mean criterion exceeded
Data Source
Special project/study
TMDL Priority
Tier IV
Class BWW1
Aquatic Life - Warm Water Type 1
Not Supported
Support Level
Not Supported
Impairment Code
4a - Pollutant-caused impairment. TMDL has been completed.
Cause Magnitude
High
Status
Continuing
Source
Urban Runoff/Stormwater
Source Confidence
N/A
Cycle Added
2002
Impairment Rationale
Pollutant-caused fish kill
Data Source
Fish kill investigation: Iowa DNR
Support Level
Not Supported
Impairment Code
5b - Biological impairment or pollutant-caused fish kill - unknown source. No administrative action.
Cause Magnitude
High
Status
Continuing
Source
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
2006
Impairment Rationale
Pollutant-caused fish kill
Data Source
Fish kill investigation: Iowa DNR
TMDL Priority
Tier IV
Support Level
Not Supported
Impairment Code
5b - Biological impairment or pollutant-caused fish kill - unknown source. No administrative action.
Cause Magnitude
High
Status
Continuing
Source
Spills/Dumping: Accidental release/spill
Source Confidence
N/A
Cycle Added
2014
Impairment Rationale
Adverse impacts on plant/animal communities
Data Source
Fish kill investigation: Iowa DNR
TMDL Priority
Tier IV
Class HH
Human Health -
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 levels of indicator bacteria (E. coli) that exceeded state water quality criteria. The presumptive Class BWW1 use was assessed as "not supported" due to multiple fish kill investigations. All other designated uses were "not assessed." Note: The previous impairment of this stream was due to fish kills related to high-temperature stormwater from summer precipitation events in the primarily urban watershed of McLoud Run. A TMDL for these thermal impacts was prepared by DNR and approved by U.S. EPA in 2007. Because, however, this TMDL did not address the potential causes of more recent fish kills (e.g., discharge of chlorinated water to the stream), this aquatic life use remains Section 303(d)-impaired and in Category 5b of Iowa's Integrated Report.

Assessment Explanation

Data Sources:

Data Source

Data Source ID

Data Type

Data Age

Site ID

Site Name

Site Description

Iowa DNR

6

WQ

CY 2010-2011

15570003

McLoud Run

Cedar Rapids
Iowa DNR6BIOSee Below1427McLoud RunCedar Rapids


Presumptive Class A1 - Indicator Bacteria: 2010-2011

Site ID

Data Source ID

# Samples / # Years

2010 Geometric Mean

2011 Geometric Mean

Annual Geometric Mean Violation

# Violations

% Violations

Significantly >10% Violations

Assessment Type

Support Level

15570003

6

23 / 2

889

1282

Yes

22

96%

Yes

Evaluated

Not


Presumptive Class BWW1 – Fish Kill Assessment:

BioNet Site ID

Date

Drainage Area (mi2)

Ecoregion

Major Drainage/ Thermal

Fish per mile

47c REMAP 25 % fish per mile

>47c REMAP 25 % fish per mile?

47c expected fish taxa

Fish Taxa Present % (>50% to pass)

1427

07/20/2023

4.12

47c

MS/WW

2714

2992

No (Fail)

4/12

33% (Fail)

The presumptive Class BWW1 use remains in Category 5b following a 2023 fish kill follow-up assessment that found the resident fish community to be below ecoregion expectations. The aquatic life use is designated as a BWW1 (warm water) stream, however the fish community from this stream more closely resembles a community from a cold water stream and is also a listed trout stream on the Iowa DNR fisheries trout stream web page. The WQMA section is currently evaluating the proper aquatic life designation for this stream.


A total of 10 fish kills occurred in this segment from 1997-2018. For more information on those historic fish kills, see previous IR assessments for this segment for view the fish kills in the Iowa Fish Kill Database -
https://programs.iowadnr.gov/adbnet/Segments/508

Details about the September 2024 fish kill caused by chlorinated water can be found here: https://programs.iowadnr.gov/fishkill/events/1071

Details about the January 2024 fish kill caused by chlorinated water can be found here: https://programs.iowadnr.gov/fishkill/Events/1052

Details about the April 2023 fish kill caused by chlorinated water can be found here:https://programs.iowadnr.gov/fishkill/events/1036

Monitoring and Methods
Assessment Key Dates
5/18/2010
Monitoring Start
7/25/2011
Monitoring End
4/3/2023
Fish Kill
1/1/2007
TMDL Completed
1/23/2024
Fish Kill
9/16/2024
Fish Kill
7/20/2023
Biological Monitoring
Methods
140
Incidence of spills and/or fish kills
150
Monitoring data more than 5 years old
330
Fish surveys
420
Indicator bacteria monitoring