Upper Iowa River IA 01-UIA-245

from confluence with unnamed tributary (NE 1/4 S21 T100N R12W Howard Co.) to IA/MN state line in S11 T100N R14W Howard 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: 3 - Insufficient data exist to determine whether any designated uses are met.
Trend: Unknown
Created: 7/31/2019 2:36:25 PM
Updated: 8/27/2019 1:09:38 PM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Assessed

Class BWW1

Aquatic Life - Warm Water Type 1

Not Assessed

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 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(WW1) aquatic life uses are considered "not assessed" (IR 3a) due to the age of the biological data upon which the previous assessments of these uses ("fully supported") were based. Fish consumption uses are considered "not assessed" (IR 3a) due to the age of the data.

Assessment Explanation

The presumptive Class A1 (primary contact recreation) uses remain “not assessed” due to the lack of data for indicator bacteria upon which to base an assessment. Upstream sites on the Upper Iowa River are monitored by as part of the Upper Iowa River Watershed Project, but these sites are located approximately five miles into Minnesota and are thus are too far removed to be useful for assessing the Class A1 uses of this segment in Iowa.

The Class B(WW1) aquatic life uses also remain “not assessed.” The most recent (2004) assessment of the Class B(WW) uses for this stream segment (“fully supported”) was based on results of biological monitoring conducted as part of an DNR stream use assessment in 1995. Because the data upon which this assessment was originally based have aged beyond 10 years--and are thus are considered too old to characterize current water quality conditions--the Class B(WW1) uses of this segment are now considered "not assessed".

Fish consumption uses are considered "not assessed" (IR 3a) due to the age of the data.

Note: Historical fish consumption data. The composite samples of fillets from smallmouth bass and golden redhorse (Moxostoma erythrurum) collected near Lime Springs in 2006 were analyzed only for mercury. These samples were collected as part of RAFT follow-up monitoring to better define the boundaries of the existing fish consumption advisory issued in 2006 for the Upper Iowa River from the Lower Dam upriver to the county road W20 bridge NW of Decorah. The level of mercury in the composite sample of golden redhorse fillets was 0.22 ppm. The level of mercury in the composite sample of smallmouth bass fillets was 0.25 ppm. The existence of, or potential for, a fish consumption advisory is the basis for Section 305(b) assessments of the degree to which Iowa’s lakes and rivers support their fish consumption uses. The results from the 2006 sampling near Lime Springs suggest that levels of mercury in fish from this segment of the Upper Iowa River are below DNR/IDPH advisory trigger levels. Thus, the fish consumption uses are assessed as “fully supported.”

Monitoring and Methods

Assessment Key Dates

6/21/2006

Fish Tissue Monitoring

Methods

260

Fish tissue analysis