Brophy Creek IA 01-WPS-358

mouth (S1 T80N R4E Clinton Co.) to confluence with Cherry Cr. in S17 T81N R5E Clinton Co.

Open Data Collection Period Modal

For purposes of developing stream/river water quality assessments for integrated reporting, three years of water quality data are typically used for both conventional pollutant parameters (e.g., indicator bacteria) and the less frequently monitored toxic parameters (e.g., toxic metals). Since the 2004 IR cycle, DNR has used a three-year data gathering period for streams, rivers, and beaches. For most assessments, the use of three years of data increases the number of samples upon which the decision on use support is based and helps address the problem of weather-related year-to-year fluctuations in water quality.

Due to the lower sampling frequency in Iowa’s ambient lake, biological, fish kill, and fish tissue monitoring programs, five years of data are used for developing IR assessments and for identifying Section 303(d) listings.

Data Type	Data Timeframe
Beach Sampling Data	CY 2012 - 2014
Stream/River Water Quality Data	CY 2012 - 2014
Lake Water Quality Data	CY 2010 - 2014
Biological Sampling Data	CY 2010 - 2014*
Fish Kill Data	CY 2010 - 2014
Fish Tissue Sampling Data	CY 2010 - 2014
Continuous Dissolved Oxygen Sampling Data	CY 2010 - 2014
*Biological sites sampled in both 2009 and 2013 were also assessed.

Open Segment Map
View assessment methodology in new window

Cycle: 2016
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown
Created: 9/15/2016 10:25:40 AM
Updated: 11/30/2016 7:55:06 AM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Assessed

Class BWW1

Aquatic Life - Warm Water Type 1

Partially Supported

Biological: low aquatic macroinvertebrate IBI

Support Level

Partially Supported

Impairment Code

5b-v - Biological - verified

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2006

Impairment Rationale

Low Biotic Index

Data Source

Biological monitoring: Iowa DNR WQMA

TMDL Priority

Tier IV

Class HH

Human Health -

Not Assessed

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" (IR 3a) due to the lack of information upon which to base an assessment. The Class B(WW1) aquatic life uses are assessed (monitored) as “partially supported” based on data collected in 2012, 2013 and 2014 as part of the IDNR/SHL follow-up sampling project. Fish consumption uses (Class HH) remain "not assessed" (IR 3a) due to the lack of fish contaminant monitoring in this stream segment.

Assessment Explanation

This monitored biological assessment was based on data collected in 2012, 2013 and 2014 as part of the IDNR/SHL follow-up stream sampling project. A series of biological metrics which 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 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 2012 FIBI score was 50 (fair) and the BMIBI score was 57 (good). The 2013 FIBI score was 64 (good) and the BMIBI score was 39 (fair). The 2014 FIBI score was 54 (good) and the BMIBI score was 44 (fair). 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 biological impairment criteria were determined from a statistical analysis of data collected at stream ecoregion reference sites from 1994-2008. The FIBI BIC for this ecoregion is 36 and the BMIBI BIC for this ecoregion is 51. This segment passed the FIBI BIC 3/3 times and passed the BMIBI BIC 1/3 times in the last five years (2010-2014).

This aquatic life assessment is now considered "monitored" based on a change in the 2010 IDNR assessment methodology. IDNR now requires a segment have two or more biological samples collected from the segment in multiple years between over a recent five-year period to be considered “monitored”. This segment had multiple samples collected in the last five years (2010-2014). This waterbody remains in IR Category 5b and moves from sub-category 5b-t (tentative/evaluated) to sub-category 5b-v (verified/monitored) and remains on Iowa’s 2016 Section 303(d) list of impaired waters.

Fish consumption uses remain "not assessed" (IR 3a) due to the lack of fish contaminant monitoring in this stream segment.

Monitoring and Methods

Assessment Key Dates

8/14/2012

Biological Monitoring

9/30/2013

Biological Monitoring

10/2/2014

Biological Monitoring

Methods

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

330

Fish surveys

380

Quantitative physical habitat assessment