Iowa DNR
ADBNet

Water Quality Assessments

Impaired Waters List

Prairie Creek IA 03-SSK-6598

from mouth (SE1/4 S34 T85N R25W) to headwaters in the NW1/4 S33 T85N R26W.

Assessment Cycle
2020
Release Status
Final
Cycle Period
2016 - 2018
Overall IR Category
5 - Water is impaired or threatened and a TMDL is needed.
Trend
Unknown
Created
9/28/2020 12:48:57 PM
Updated
10/9/2020 1:40:41 PM
Assessment conducted in accordance with Iowa's 2020 IR methodology
Use Support
Class A1
Not Supported
Bacteria: Indicator Bacteria- E. coli
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
Volunteer monitoring
TMDL Priority
Tier III
Class BWW1
Not Assessed
General Use
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. 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 2008-2012

908022

Prairie Creek

Site SC-13


Presumptive Class A1 - Indicator Bacteria:

Site ID

Data Source ID

# Samples / # Years

2008-2012 Geometric Mean

Annual Geometric Mean Violation

# Violations

% Violations

Significantly >10% Violations

Assessment Type

Support Level

908022

6

9 / 5

1070

Yes

9

100%

Yes

Evaluated

Partial


Presumptive Class BWW1 - No Data

Monitoring and Methods
Assessment Key Dates
5/10/2008 Fixed Monitoring Start Date
5/12/2012 Fixed Monitoring End Date
Methods
420 Water column surveys (e.g. fecal coliform)
830 (VOL.) Bacteriological water column sampling by quality-assured volunteers
150 Monitoring data more than 5 years old
220 Non-fixed station physical/chemical monitoring (conventional pollutant only)