Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Prairie Creek IA 02-IOW-6396

mouth (S31 T77N R5W Johnson Co.) to the Lone Tree wastewater treatment plant outfall (NE1/4 S16 T77N R5W Johnson Co.)

Cycle
2024
Release Status
Final
Overall IR
5 - Water is impaired or threatened and a TMDL is needed.
Trend
Unknown
Created
11/1/2023 8:14:10 AM
Updated
1/17/2024 1:02:12 PM
Use Support
Class A1
Recreation - Primary contact
Not Assessed
Class BWW1
Aquatic Life - Warm Water Type 1
Not Assessed
General Use
General Use water -
Not Supported
Support Level
Not Supported
Impairment Code
5a - Pollutant-caused impairment. TMDL needed.
Cause Magnitude
High
Status
Continuing
Source
Municipal Wastewater Treatment Plant
Source Confidence
High
Cycle Added
2010
Impairment Rationale
Narrative criteria violation: wastewater impacts
Data Source
UAA surveys: Iowa DNR
TMDL Priority
Tier IV
Impairment Delistings
No delistings for this assessment cycle.
Documentation
Assessment Summary

The General Use of this stream was assessed as "not supported" due to impacts of poorly-treated wastewater discharged to the stream that resulted in a violation of Iowa’s narrative water quality criteria (IAC 61.3(2)). The basis for assessment were the results of a Use Attainability Analysis (UAA) conducted by Iowa DNR staff in 2006. All other designated uses were "not assessed."

Assessment Explanation

The identification of the impairment of the general use for this assessment segment was based on results of observations and biological monitoring conducted by DNR staff on September 26, 2006 as part of a UAA for Prairie Creek in Johnson County near the outfall of the Lone Tree WWTP. The following comments from the UAA are relevant to this assessment (see http://programs.iowadnr.gov/uaa/search.aspx):

“The effluent coming from the Lone Tree WWTP discharge pipe smelled strongly of sewage. The creek and the creek bed at site (539-3) near the outfall smelled of sewage. There was a white fungus found in the creek at this site. The water in the creek was a milky color in places. It should be noted that upstream of the WWTP discharge pipe, there was no smell and the water in the creek was clear. At the downstream sites, the creek appeared normal. No white fungus was observed and the creek did not smell of sewage.” (http://programs.iowadnr.gov/uaa/resources1/uaa/136/Prairie%20Creek%20-%20Recreation%20UA-UAA.doc)

These comments suggest poor water quality conditions and potential violations of several of Iowa's narrative water quality standards (IAC 61.3(2)) designed to protect the general use of Iowa's surface waters (e.g., livestock and wildlife watering, aquatic life and non-contact recreation):

--such waters shall be free from substances from point source dischargers that will settle to form sludge deposits;

--such waters shall be free from floating debris, oil, grease, scum and other materials from wastewater discharges or agricultural practices in amounts sufficient to create a nuisance;

--such waters shall be free from materials from wastewater discharges or agricultural practices producing objectionable color, odor, or other aesthetically objectionable conditions;

--such waters shall be free from substance attributable to wastewater discharges or agricultural practices in concentrations or combinations which are acutely toxic to human, animal, or plant life.

Based on the information from the September 2006 UAA, the general use of this stream segment was assessed as "not supported" due to water quality impacts from poorly-treated domestic sewage. Waters assessed as “not supported” are considered appropriate for addition to Iowa’s Section 303(d) list of impaired waters.

Monitoring and Methods
Assessment Key Dates
9/26/2006
Biological Monitoring
Methods
120
Surveys of fish and game biologists/other professionals
150
Monitoring data more than 5 years old
175
Occurrence of conditions judged to cause impairment
330
Fish surveys
375
Qualitative physical habitat assessment