Drainage Ditch 61 IA 06-LSR-1953

from Trumbull Lake to headwaters

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: 7/29/2019 7:41:53 AM
Updated: 7/29/2019 7:43:33 AM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Assessed

Class BWW1

Presumptive Use

Aquatic Life - Warm Water Type 1

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" due to the lack of data for indicator bacteria (E. coli) upon which to base an assessment. The presumptive Class B(WW1) aquatic life uses remain assessed as “fully supported” based on results of chemical/physical water quality monitoring during 2005. The source of data for this assessment is the results of DNR/SHL water quality monitoring conducted as part of TMDL development from March through September 2005 at station 11210001.

Assessment Explanation

The presumptive Class B(WW1) aquatic life uses remain assessed (evaluated) as “fully supported” based on results of DNR/SHL TMDL-related water quality monitoring conducted in 2005 at station 11210001. Results of this monitoring showed no violations of Class B(WW1) water quality criteria for conventional parameters dissolved oxygen or pH in the 12 samples collected or for ammonia in the 11 samples collected from March-September 2005. One of the 12 samples violated the Iowa criterion water temperature:the water temperature of the sample collected on August 9, 2005 was 32.7 C, thus exceeding the water temperature criterion of 32 C. According to U.S.EPA guidelines for Section 305(b) water quality assessments (U.S.EPA 1997b, page 3-17), the percentage of violations at this station during the 2004-2006 period for temperature (8%) does not suggest a water quality impairment. These guidelines allow up to 10% violations of conventional parameters such as dissolved oxygen, pH, and water temperature before impairment of water quality is indicated. The violation of the criteria for water temperature is likely related to naturally-occurring conditions (bright sunshine, warm air temperatures, and a small prairie stream) and does not reflect the influence of anthropogenic pollutants.

Monitoring and Methods

Assessment Key Dates

3/31/2005

Fixed Monitoring Start Date

9/27/2005

Fixed Monitoring End Date

Methods

150

Monitoring data more than 5 years old

220

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