Long Creek IA 05-GRA-1364

mouth (S8 T69N R28W Decatur Co.) to confluence with East Long Cr. in S36 T71N R27W Clarke 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.

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Cycle: 2016
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: Stable
Created: 9/20/2016 2:14:32 PM
Updated: 9/21/2016 9:14:01 AM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Assessed

Class BWW2

Aquatic Life - Warm Water Type 2

Fully Supported

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(WW-2) aquatic life uses are assessed (monitored) as "fully supported" (IR 2a) based on results of USGS chemical/physical monitoring in 2012-2014 and IDNR/SHL biological sampling in 2001, 2010 and 2014. This assessment is based on results of (1) USGS chemical/physical water quality monitoring at Long Creek near Van Wert, during the 2012-2014 period, and (2) IDNR/SHL biological sampling in 2001, 2010 and 2014.

Assessment Explanation

[Note: Prior to the 2008 Section 305(b) cycle, this stream segment was designated only for Class B(LR) aquatic life uses. Due to changes in Iowa’s surface water classification that were approved by U.S. EPA in February 2008 (see http://www.iowadnr.com/water/standards/files/06mar_swc.pdf), this segment is now presumptively designated for Class A1 (primary contact recreation) uses. The stream remains designated for aquatic life uses (now termed Class B(WW2) aquatic life uses). Thus, for the current assessment, the available water quality monitoring data will be compared to the applicable Class A1 and Class B(WW2) water quality criteria.]

The Class B(WW-2) aquatic life uses are assessed (evaluated) as “fully supporting" based on biological data collected in 2001, 2010 and 2014 as part of the IDNR/SHL stream biocriteria project. The 2001 FIBI score was 38 (fair) and the BMIBI score was 51 (fair). The 2010 FIBI score was 41 (fair) and the BMIBI score was 61 (good). The 2014 FIBI score was 16 (poor) and the BMIBI score was 52 (fair). The aquatic life use support was assessed (evaluated) as fully supported (=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 33 and the BMIBI BIC for this ecoregion is 41. This segment passed the FIBI BIC 2/3 times and passed the BMIBI BIC 3/3 times in the last 14 years.

This aquatic life assessment is now considered "evaluated" 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 over a recent five-year period to be considered “monitored”. This segment had multiple samples collected in the previous 14 years; however, the multiple samples were not collected during a recent five-year period. Despite this change in assessment methodology and type, this waterbody remains in IR Category 2a

Results of chemical/physical water quality monitoring at the Long Creek near Van Wert by USGS also suggest “full support” of the aquatic life uses. Monitoring showed no violations of Class B(WW2) water quality criteria for 11 Ammonia samples (maximum = 0.2 mg/L), 11 Dissolved Oxygen samples (minimum = 7 mg/L), 11 pH samples (range = 7.7 to 8.2), 11 Temperature samples (maximum = 31.1° c), 11 Chloride samples (maximum = 7.6 mg/L), or 11 Sulfate samples (maximum = 34.4 mg/L) occurred during monitoring from May 2013 to August 2013. According to U.S. EPA guidelines for Section 305(b) water quality assessments (U.S. EPA 1997b, page 3-17), the EPA guidelines allow up to 10% violations of these conventional parameters before impairment of water quality is indicated. Thus, these results thus suggest “monitored/full support” of the Class B(WW2) aquatic life uses.

Monitoring and Methods

Assessment Key Dates

5/9/2013

Fixed Monitoring Start Date

8/7/2013

Fixed Monitoring End Date

8/30/2010

Biological Monitoring

10/11/2001

Biological Monitoring

7/16/2014

Biological Monitoring

Methods

150

Monitoring data more than 5 years old

220

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

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

330

Fish surveys

380

Quantitative physical habitat assessment