2024 assessment for Elk Creek

Elk Creek IA 01-TRK-176

confluence with Steeles Br. (S26 T91N R4W Clayton Co.) to confluence with unnamed tributary in S13 T90N R4W Delaware Co.

2024
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 2020 - 2022
Stream/River Water Quality Data	CY 2020 - 2022
Lake Water Quality Data	CY 2018 - 2022
Biological Sampling Data	CY 2018 - 2022*
Fish Kill Data	CY 2018 - 2022
Fish Tissue Sampling Data	CY 2018 - 2022
Continuous Dissolved Oxygen Sampling Data	CY 2018 - 2022
*Biological sites sampled in both 2017 and 2021 were also assessed.

Open Segment Map
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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

12/12/2023 10:28:53 AM by

Updated

5/9/2024 1:12:40 PM by

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

303(d) Delistings for this Cycle

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class BWW2 use was assessed as "fully supported" based on biological sampling data and a DNR Fisheries Bureau summary on trout reproduction. All other designated uses were "not assessed."

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	BIO	See Below	1144	Elk Creek	Greeley

Presumptive Class A1 – No Data

Class BWW2 - Biological Sampling:

Fish:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage/Thermal	Riffle Stream?	FIBI score	FIBI Class	52bFIBI BIT	FIBI Pass/Fail
1144	7/14/21	22.6	52b	MS/WW	NA	54	Excellent	52	Pass

Overall Assessment:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Fish	Evaluated	Pass (1/1)	FS
Overall	Evaluated	Pass	FS	1	Assessment was evaluated because it was based on single FIBI score.

Class BWW2: Natural Trout Reproduction:

Even though Elk Creek is classified as a BWW2 stream, based on the January 2024 trout reproduction in Iowa streams summary prepared by the DNR Fisheries Bureau, the Class BWW2 aquatic life use of Elk Creek was assessed as "fully supported." According to the updated summary, this stream was placed in Category I: streams that exhibit consistent natural reproduction and maintain a wild population of one or more trout species without any stocking.

Monitoring and Methods

Assessment Key Dates

7/14/2021

Biological Monitoring

1/1/2024

Biological Monitoring

Methods

315

Regional reference site approach

330

Fish surveys