Iowa DNR
Iowa DNR
ADBNet
Water Quality Assessments
Impaired Waters List

Black Cat Creek IA 04-EDM-980

mouth (S24 T96N R29W Kossuth Co.) to north line of S5 T97N R30W Kossuth Co.

Cycle
2018
Release Status
Final
Overall IR
3 - Insufficient data exist to determine whether any designated uses are met.
Trend
Unknown
Created
5/14/2019 1:15:14 PM
Updated
5/14/2019 1:20:54 PM
Use Support
Class A1
Recreation - Primary contact
Not Assessed
Class BWW2
Aquatic Life - Warm Water Type 2
WINOFI
Impairment Code
3b-c - Use potentially biologically impaired based on calibrated IBI metrics.
Cause Magnitude
Slight
Status
New
Source
Unknown: Source Unknown
Source Confidence
N/A
Cycle Added
2018
Impairment Rationale
Low Biotic Index
Data Source
Biological monitoring: Iowa DNR WQMA
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 the lack of information upon which to base an assessment. The Class B(WW2) aquatic life uses are assessed (evaluated) as “partially supporting” based on data collected in 2005, 2011 and 2015 as part of the DNR/SHL stream biological sampling projects.

Assessment Explanation

This evaluated biological assessment was based on data collected in 2003, 2005 and 2011 as part of the DNR/SHL stream sampling projects. A series of biological metrics which reflect stream water quality and habitat integrity were calculated from the biological sampling data. The biological metrics are based on the numbers and types of benthic macroinvertebrate taxa and fish species collected in the stream sampling reach. The biological metrics were combined to make a fish community index of biotic integrity (FIBI) and a benthic macroinvertebrate index (BMIBI). The indexes rank the biological integrity of a stream sampling reach on a rising scale from 0 (minimum) to 100 (maximum). The 2015 FIBI score was 30 (fair) and the 2003 BMIBI scores were 38 (fair) and 61 (good). The 2005 stream REMAP FIBI score was 31 (fair) and the 2006 BMIBI score was 61 (good). The 2011 FIBI score was 51 (good) and the BMIBI score was 64 (good). The aquatic life use support was assessed as partially supporting (=PS), based on a comparison of the FIBI and BMIBI scores with biological impairment criteria (BIC) established for previous Section 305(b) reports. The non-riffle habitat FIBI BIC for this ecoregion is 32 and the BMIBI BIC for this ecoregion is 62. This segment passed the FIBI BIC 1/3 times and passed the BMIBI BIC 1/4 times in the past 12 years. The biological impairment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2008.

This aquatic life assessment is now also considered "evaluated" based on a change in the 2010 DNR assessment methodology. DNR now requires a segment have two or more biological samples collected from the segment in multiple years between 2012 and 2016 to be considered “monitored”. This assessment required the use of samples collected in the previous 12 years (2005-2016) for completion. According to DNR’s assessment/listing methodology, impairments based on “evaluated” assessments are of lesser confidence and are thus not appropriate for Section 303(d) listing (Category 5 of the Integrated Report). DNR does, however, consider these impairments as appropriate for listing under either Category 2b or 3b of the Integrated Report (waters potentially impaired and in need of further investigation).

Monitoring and Methods
Assessment Key Dates
9/9/2015
Biological Monitoring
8/16/2005
Biological Monitoring
8/15/2011
Biological Monitoring
7/28/2015
Biological Monitoring
Methods
150
Monitoring data more than 5 years old
315
Regional reference site approach
320
Benthic macroinvertebrate surveys
330
Fish surveys
380
Quantitative physical habitat assessment