Middle River IA 04-LDM-1086

from confluence with Clanton Cr. (S28T76N R25W Warren Co.) to confluence with Bush Branch in S8 T75N R29W Madison 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 2014 - 2016
Stream/River Water Quality Data	CY 2014 - 2016
Lake Water Quality Data	CY 2012 - 2016
Biological Sampling Data	CY 2012 - 2016*
Fish Kill Data	CY 2012 - 2016
Fish Tissue Sampling Data	CY 2012 - 2016
Continuous Dissolved Oxygen Sampling Data	CY 2012 - 2016
*Biological sites sampled in both 2011 and 2015 were also assessed.

Open Segment Map
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Cycle: 2018
Release Status: Final
Overall IR: 2 - Some of the designated uses are met but there is insufficient data to determine if remaining designated uses are met.
Trend: Unknown
Created: 5/15/2019 9:04:25 AM
Updated: 5/15/2019 9:12:05 AM

Use Support

Class A1

Recreation - Primary contact

Not Assessed

Class BWW1

Aquatic Life - Warm Water Type 1

Fully Supported

Class HH

Human Health -

Fully Supported

General Use

General Use water -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 (primary contact recreation) uses remain "not assessed" due to the lack of information upon which to base an assessment. The Class B(WW1) aquatic life uses are assessed (monitored) as "fully supported” based on results of biological sampling in 2012, 2015 and 2016. Fish consumption uses are assessed (evaluated) as "fully supported" based on results of fish contaminant monitoring in 2014. Sources of data for this assessment include (1) results of DNR/SHL biological sampling conducted in 2012, 2015 and 2016 as part of the stream biocriteria project, and (2) results of U.S. EPA/DNR fish contaminant (RAFT) monitoring in 2014.

Assessment Explanation

The Class B(WW1) aquatic life uses are assessed (evaluated) as "fully supported” based on results of DNR/SHL biological sampling conducted on this stream segment in 2012, 2015 and 2016. The 2016 FIBI score was 50 (fair) and the BMIBI score was 71 (good). The 2015 FIBI score was 48 (fair) and the BMIBI scores were 50 (fair) and 60 (good). The 2012 FIBI score was 40 (fair) and the BMIBI score was 63 (good). The aquatic life use support was assessed as fully supporting (=FS), 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 2/3 times and passed the BMIBI BIC 3/4 times in the last five years.

This aquatic life assessment is now considered "monitored" 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 over a recent five-year period to be considered “monitored”. This segment had multiple samples collected in the previous five years (2012-2016).

Fish consumption uses areassessed (monitored) as “fully supported” based on results of U.S.EPA/DNR fish contaminant monitoring southwest of Winterset in 2014. The composite samples of fillets from channel catfish and tissue plugs from flathead catfishhad low levels of contaminants. Levels of primary contaminants in the composite sample of channel catfish fillets were as follows: mercury: 0.08 ppm; total PCBs: <0.06 ppm; and technical chlordane: <0.05 ppm. The average level of mercury in the five flathead catfish analyzed was 0.068 ppm. These levels of contaminants are far below Iowa DNR/Iowa Dept. of Public Health consumption advisory thresholds and thus suggest “full support” of fish consumption uses.

Monitoring and Methods

Assessment Key Dates

9/9/2016

Biological Monitoring

10/13/2015

Biological Monitoring

7/16/2012

Biological Monitoring

7/23/2014

Fish Tissue Monitoring

8/27/2015

Biological Monitoring

Methods

260

Fish tissue analysis

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

330

Fish surveys

380

Quantitative physical habitat assessment