2018 assessment for Elk River

Elk River IA 01-MAQ-8

mouth (Clinton Co.) to North Branch Elk River (S10 T83N R6E Clinton Co.)

2018
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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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

5/8/2019 2:41:09 PM by

Updated

5/8/2019 2:45:06 PM by

Use Support

Class A1

Recreation - Primary contact

Not Assessed

Class BWW1

Aquatic Life - Warm Water Type 1

Fully Supported

Class HH

Human Health -

Not Assessed

General Use

General Use water -

Not Assessed

303(d) Delistings for this Cycle

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(WW) aquatic life uses remain assessed (monitored) as "fully supported" based on results of biological sampling in 2012 and 2013. Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this stream reach. The source of data for this assessment is the results of DNR/SHL biological sampling near Teeds Grove in 2012 and 2013.

Assessment Explanation

This monitored aquatic life assessment was based on data collected in 2012 and 2013 as part of the DNR/SHL stream biological sampling project. 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 2012 FIBI score was 53 (good) and the BMIBI score was 52 (fair). The 2013 FIBI score was 53 (good) and the BMIBI score was 56 (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 FIBI BIC for this ecoregion is 36 and the BMIBI BIC for this ecoregion is 51. This segment passed the FIBI BIC 2/2 times and passed the BMIBI BIC 2/2 times in the last five years. The biological impairment criteria were determined from a statistical analysis of biological data collected at stream ecoregion reference sites from 1994-2008. This aquatic life assessment is now considered "monitored" because this segment had two or more biological samples collected in multiple years over the last five-year peiod.

The Class A1 (primary contact recreation) and Class HH (fish consumption) uses remain "not assessed" due to the lack of water quality or fishcontaminant monitoring in this stream reach.

Monitoring and Methods

Assessment Key Dates

8/12/2013

Biological Monitoring

8/13/2012

Biological Monitoring

Methods

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

330

Fish surveys

380

Quantitative physical habitat assessment