Soap Creek IA 04-LDM-1032

mouth (S35 T71N R12W Wapello Co.) to confluence with Little Soap Cr. in S1 T70N R13W Davis 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
View assessment methodology in new window

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: 5/14/2019 2:23:20 PM
Updated: 5/14/2019 2:25:26 PM

Use Support

Class A1

Presumptive Use

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

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class B(WW1) aquatic life uses are assessed (monitored) as "fully supported" based on results of DNR/SHL biological sampling in 2010 and 2013. The Class A1 (primary contact recreation) and Class HH (human health/fish consumption) uses remain "not assessed" due to the lack of data upon which to base an assessment.

Assessment Explanation

The presumptive Class B(WW1) aquatic life uses are assessed (monitored) as “fully supporting” based on biological data collected in 2010 and 2013 as part of the DNR/SHL stream biocriteria project. The 2010 FIBI score was 51 (good) and the BMIBI score was unavailable. The 2013 FIBI score was 35 (fair) and the BMIBI score was 52 (fair). 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 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 2/2 and BMIBI BIC 1/1 times in the past seven years.

This aquatic life assessment is now considered "evaluated" based on a change in the 2010 DNR assessment methodology. DNR now requires a segment have two or more biological samples collected from the segment in multiple years over the most recent five-year period to be considered “monitored”. This segment had multiple samples collected in the previous seven years (2010-2016).

The Class A1 (primary contact recreation) and Class HH (human health/fish consumption) uses remain "not assessed" due to the lack of data upon which to base an assessment.

Monitoring and Methods

Assessment Key Dates

10/4/2010

Biological Monitoring

10/10/2013

Biological Monitoring

Methods

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

330

Fish surveys

380

Quantitative physical habitat assessment