Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Flint Creek IA 02-ICD-6308

from confluence with unnamed tributary (T71N R04W Sec21 Des Moines Co.) to headwaters (T71N R05W Sec23 NW Henry Co.)

Cycle
2018
Release Status
Final
Overall IR
3 - Insufficient data exist to determine whether any designated uses are met.
Trend
Unknown
Created
7/22/2019 11:47:33 AM
Updated
7/22/2019 11:50:01 AM
Use Support
Class A1
Recreation - Primary contact
Not Assessed
Class BWW1
Aquatic Life - Warm Water Type 1
WINOFI
Impairment Code
3b - Use potentially impaired based on an evaluated assessment.
Cause Magnitude
Moderate
Status
Continuing
Source
Agriculture: Crop Production
Source Confidence
High
Cycle Added
2010
Impairment Rationale
Pollutant-caused fish kill
Data Source
Fish kill investigation: Iowa DNR
General Use
General Use water -
Not Assessed
Impairment Delistings
No delistings for this assessment cycle.
Documentation
Assessment Summary

The presumptive Class A1 (primary contact recreation) uses remain "not assessed" due to a lack of information upon which to base an assessment. The Class B(WW1) aquatic life uses remain assessed as "partially supported" due to a fish kill in July 2009.

Assessment Explanation

The kill occurred on or before July 31, 2009 and was attributed to aerial spraying of the pesticides Cobalt and Laredo. Approximately 542 fish were killed along 1.6 miles of Flint Creek two miles northeast of New London. The value of the fish was estimated to be $7342.74. Updated information shows that DNR sought and received restitution for this fish kill.

According to DNR’s assessment/listing methodology, the occurrence of a single pollutant-caused fish kill, or a fish kill of unknown origin, on a waterbody or waterbody reach during the most recent assessment period indicates a severe stress to the aquatic community and suggests that the aquatic life uses should be assessed as “impaired.” If a cause of the kill is identified, and the cause is either known, or suspected, to be a “pollutant,” the assessment type is considered “monitored” and the affected waterbody is a candidate for Section 303(d) listing. If, however, a consent order has been issued to the party responsible for the kill and monetary restitution has been sought for the fish killed, the affected waterbody will be placed in IR Category 4d (impaired but TMDL not required). DNR feels that (1) TMDLs should not be required for kills caused by a one-time illegal or unauthorized release of manure or other toxic substance where enforcement actions were taken and (2) enforcement action is more appropriate, efficient, and effective for addressing a spill-related impairment than is the TMDL process. Thus, this assessment segment was placed in Category 4d of Iowa’s 2012 Integrated Report. According to Iowa DNR’s assessment/listing methodology, if no additional fish kills have occurred over at least a five-year period, the assessment of impairment should be considered “evaluated” (i.e., of lower confidence), and the waterbody segment should be moved from IR Category 4d to IR Category 3b (list of waters in need of further investigation). This, this assessment was moved from IR Category 4d (impaired; TMDL not required) to IR Category 3b (potentially impaired).

Monitoring and Methods
Assessment Key Dates
7/31/2009
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