Little Sioux River IA 06-LSR-1567

from confluence with Willow Cr. near Washta (S30 T90N R41W Cherokee Co.) to Highway 3 at Cherokee in S26 T92N R40W Cherokee 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: 5/31/2019 9:56:49 AM
Updated: 7/30/2019 11:07:17 AM

Use Support

Class A1

Recreation - Primary contact

Not Assessed

Class BWW1

Aquatic Life - Warm Water Type 1

Not Assessed

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 fish consumption uses remain assessed (monitored) as "fully supported" based on results of DNR fish tissue monitoring near Washta (Cherokee Co.) in 2012, 2014, and 2016. This assessment is the same as that used for the adjacent downstream segment (IA 06-LSR-1566). The Class A1 (primary contact recreation) uses and the Class B(WW1) aquatic life uses remain "not assessed" due to the lack of water quality data upon which to base an assessment.

Assessment Explanation

Fish consumption uses are assessed (monitored) as "fully supported" based on the 2012, 2014 and 2016 DNR fish tissue sampling on the Little Sioux River south of Washta. This site has been sampled for whole-fish common carp since 1994 on an every-other-year basis as part of RAFT trend monitoring. The results from the 2012, 2014 and 2016 samplings show low levels of the primary contaminants (chlordane, PCBs and mercury) in the composite whole-fish samples of common carp: 2012 sample: mercury: 0.062 ppm; total PCBs: <0.09 ppm; and technical chlordane: <0.03 ppm; 2014 sample: mercury: 0.05 ppm; total PCBs: <0.24 ppm; and technical chlordane: <0.06 ppm. The results of the 2016 sampling are similar with all contaminant levels in the composite sample of whole-fish common carp well-below advisory thresholds: mercury: 0.06 ppm; total PCBS: <0.06 ppm, and chlordane: 0.03 ppm. The existence of, or potential for, a fish consumption advisory is the basis for Section 305(b) assessments of support of fish consumption uses in Iowa’s rivers and lakes. The fish contaminant data generated from the 2012, 2014, and 2016 fish tissue sampling conducted at this river segment show that the levels of contaminants do not exceed any of the advisory trigger levels, thus indicating no justification for issuance of a consumption advisory for this waterbody.

Monitoring and Methods

Assessment Key Dates

9/1/2016

Fish Tissue Monitoring

8/12/2014

Fish Tissue Monitoring

9/24/2012

Fish Tissue Monitoring

Methods

260

Fish tissue analysis