Turkey River IA 01-TRK-149

from confluence with Volga R. (Clayton Co.) to west line of S9 T93N R5W Clayton Co. (two stream miles downstream from Big Spring Trout Hatchery).

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
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Cycle: 2016
Release Status: Final
Overall IR: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown
Created: 4/7/2016 11:01:08 AM
Updated: 9/29/2016 7:40:31 AM

Use Support

Class A1

Recreation - Primary contact

Not Supported

Bacteria: Indicator Bacteria- E. coli

Support Level

Not Supported

Impairment Code

5a - Pollutant-caused impairment. TMDL needed.

Cause Magnitude

Slight

Status

New

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2016

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Watershed project monitoring

TMDL Priority

Tier III

Class BWW1

Aquatic Life - Warm Water Type 1

Fully Supported

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 Class A1 (primary contact recreation) uses are assessed (monitored) as not supporting (IR Category 5a) based on bacterial monitoring from 2012-2014. This is a new impairment for this assessment segment. The Class B(WW1) aquatic life uses are assessed (monitored) as "fully supported" (IR Category 2a) based on results of water quality monitoring during the 2012-2014 period. Fish consumption uses remain “not assessed” (IR Category 3a) due to the lack of monitoring data upon which to base an assessment. The source of data for this assessment is the results of water quality monitoring from April 2012 to November 2014 at Highway 13 (STORET station 15220045, aka, TR28).

Assessment Explanation

The Class A1 (primary contact recreation) uses are assessed (monitored) as "not supported" based on levels of indicator bacteria that slightly exceed state water quality criteria. The geometric mean of indicator bacteria (E. coli) in the three recreation seasons (March-November) of the 2012-2014 period were as follows: 2012: 109 orgs/100 ml., 2013: 413 orgs/100 ml, and 2014: 62 orgs/100 ml. Seven of the 24 samples exceeded Iowa’s single sample maximum criterion of 235 orgs/100 ml. The 2012 and 2014 geometric means are below the Class A1 standard of 126 orgs/100 ml. Only the 2013 geometric mean exceeded this criterion. According to IDNR’s assessment/listing methodology, if a recreation season geometric mean is greater than 126 orgs/100 ml., the primary contact recreation uses are assessed as impaired (see pgs 3-33 to 3-35 of U.S. EPA 1997b). Thus, the Class A1 (primary contact recreation) uses of this segment are assessed as “not supported”.

Results of chemical/physical water quality monitoring from 2012 through 2014 do not suggest impairment of the Class B(WW1) aquatic life uses. Monitoring at station 15220045 at Hwy. 13 showed no violations of Class B(WW1) water quality criteria for ammonia, dissolved oxygen, pH, or chloride in the approximately 20 samples analyzed. Thus, the Class B(WW1) aquatic life uses are assessed (monitored) as “fully supported”.

Fish consumption uses remain “not assessed” due to the lack of monitoring data upon which to base an assessment.

Monitoring and Methods

Assessment Key Dates

4/4/2012

Fixed Monitoring Start Date

11/5/2014

Fixed Monitoring End Date

Methods

220

Non-fixed station physical/chemical monitoring (conventional pollutant only)

420

Indicator bacteria monitoring