Iowa DNR

Water Quality Assessments

Impaired Waters List

Helmer Creek IA 01-WPS-1948

mouth (T85N R04W Sec30) to headwaters (T86N R04W Sec31 NE) Jones Co.

Assessment Cycle
Release Status
Data Collection Period
Overall IR Category
3 - Insufficient data exist to determine whether any designated uses are met.
8/30/2016 12:45:06 PM
11/30/2016 8:06:04 AM
Assessment conducted in accordance with Iowa's 2016 IR methodology
Use Support
Class A1
Not Assessed
Class BWW1
Biological: low fish IBI
Support Level
Water in Need of Further Investigation (WINOFI)
Impairment Code
3b-u - Use potentially biologically impaired based on uncalibrated IBI metrics.
Cause Magnitude
Unknown: Source Unknown
Source Confidence
Cycle Added
Impairment Rationale
Low Biotic Index
Data Source
Biological monitoring: Iowa DNR WQMA
General Use
Not Assessed
Impairment Delistings
No delistings for this assessment cycle.
Assessment Summary

The presumptive Class A1 (primary contact recreation) uses remain "not assessed" (IR 3a) due to the lack of information upon which to base an assessment.   The presumptive Class B(WW1) aquatic life uses remain assessed (evaluated) as “partially supporting” (IR 3b-u) based on results of IDNR/SHL biological sampling in 2005.  

Assessment Explanation

The presumptive Class B(WW1) aquatic life uses remain assessed (evaluated) as "partially supporting" based on data collected in 2005 as part of the IDNR/SHL stream REMAP project.   A series of biological metrics that reflect stream water quality and habitat integrity were calculated from the biocriteria sampling data.   The biological metrics are based on the numbers and types of fish species collected in the stream sampling reach.   The biological metrics were combined to make a fish community index of biotic integrity (FIBI).   The index ranks the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum).   The 2005 FIBI score was 27 (fair).   Data were unavailable to calculate the BMIBI score due to damaged sustained to the sampling equipment by beaver activity.   The aquatic life use support was assessed (evaluated) as partially supporting (=PS), based on a comparison of the FIBI score with the biological impairment criteria (BIC) established from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2008.   The non-riffle habitat FIBI BIC for this ecoregion is 44.   Even though this site failed to meet the FIBI BIC, it is uncertain as to whether or not this segment is meeting the aquatic life criteria because it is a small headwater stream and doesn’t fall in the calibrated watershed size.   Additionally, because these data are now considered too old (greater than five years) to accurately characterize current water quality conditions, the assessment category is considered “evaluated” (indicating an assessment with relatively lower confidence) as opposed to "monitored" (indicating an assessment with relatively higher confidence).  

This assessment is considered “evaluated” (of lower confidence) due to the lack of a biological assessment protocol for headwater streams.   Prior to the changes in Iowa’s surface water classification that were approved by U.S.  EPA in February 2008, this stream was classified only for general uses due to the inability of the stream to support a viable aquatic community at low-flow conditions.   IDNR’s existing biological assessment protocol, however, was calibrated to aquatic life reference conditions in larger wadeable streams with perennial flow.   The aquatic environment of most headwater streams is one of extremes in water quality.   Consequently, intermittent headwater streams tend to have biological diversity that is low relative to more stable aquatic environments of larger streams with perennial flow.   Thus, the use of biological assessment methods developed for the ecologically more stable and diverse streams will likely overstate the existence of impairment in headwater streams.   For these reasons, headwater stream reaches that show a failure to meet regional expectations for aquatic biota (fish or aquatic macroinvertebrates) will not be added to Iowa’s Section 303(d) list of impaired waters (Category 5 of the Integrated Report).   The assessment type for these assessed waters will be considered "evaluated" (indicating an assessment with relatively lower confidence) as opposed to “monitored" (indicating an assessment with relatively high confidence).   Such waters will be placed in either Category 2b or 3b of the IR and thus will be added to the state’s list of “waters in need of further investigation”.

Monitoring and Methods
Assessment Key Dates
8/31/2005 Biological Monitoring
150 Monitoring data more than 5 years old
315 Regional reference site approach
330 Fish surveys
380 Quantitative physical habitat assessment