Grannis Creek IA 01-VOL-322

mouth (S30 T93N R7W Fayette Co.) to west line of S36 T93N R8W Fayette Co.

Assessment Cycle

2022

Release Status

Final

Data Collection Period

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 2018 - 2020
Stream/River Water Quality Data	CY 2018 - 2020
Lake Water Quality Data	CY 2016 - 2020
Biological Sampling Data	CY 2016 - 2020*
Fish Kill Data	CY 2016 - 2020
Fish Tissue Sampling Data	CY 2016 - 2020
Continuous Dissolved Oxygen Sampling Data	CY 2016 - 2020
*Biological sites sampled in both 2015 and 2019 were also assessed.

Overall IR Category: 5 - Water is impaired or threatened and a TMDL is needed.
Trend: Unknown

Created: 1/6/2022 11:28:22 AM
Updated: 2/14/2022 7:17:42 AM

Assessment conducted in accordance with Iowa's 2022 IR methodology

Use Support

Class A1

Recreation

Primary contact

Presumptive Use

Not Supported

Impairments

Support Level

Not Supported

Impairment Code

5p - Impairment occurs on a waterbody with a presumptive A1 or B(WW1) use.

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2014

Impairment Rationale

Geometric mean criterion exceeded

Data Source

Watershed project monitoring

TMDL Priority

Tier III

Class A2

Recreation

Secondary contact

Fully Supported

Class BCW1

Aquatic Life

Cold Water Type 1

Fully Supported

Class HH

Human Health

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class A1 use was assessed as “not supported” due to levels of indicator bacteria (E. coli) that exceeded state water quality criteria. The Class A2 use was assessed as "fully supported” based on indicator bacteria (E. coli) monitoring data. The Class BCW1 use was assessed as "fully supported" based on water quality monitoring data and on the trout reproduction in Iowa streams summary prepared by the DNR Fisheries Bureau. 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	WQ	CY 2012-2014	15330005	Grannis Cr @ Fox Road (GRA10)

Presumptive Class A1 - Indicator Bacteria: Historical

Site ID	Data Source ID	# Samples / # Years	2012 Geometric Mean	2013 Geometric Mean	2014 Geometric Mean	Annual Geometric Mean Violation	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
15330005	6	24 / 3	267	152	203	Yes	10	42%	Yes	Evaluated	Not

Class A2 - Indicator Bacteria: Historical

Site ID	Data Source ID	# Samples / # Years	2012 Geometric Mean	2013 Geometric Mean	2014 Geometric Mean	Annual Geometric Mean Violation	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
15330005	6	24 / 3	267	152	203	No	2	8%	No	Evaluated	Full

Class BCW1 - Conventional Parameters: Historical

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Acute / Chronic Violations	% Acute/ Chronic Violations	Significantly >10% Violations	Assessment Type	Support Level
15330005	6	Ammonia	16 / 2	0.16	0.06	0.05	0 / 0	0% / 0%	No	Evaluated	Full
15330005	6	Chloride	16 / 2	33	31	31	0 / 0	0% / 0%	No	Evaluated	Full
15330005	6	Dissolved oxygen	24 / 3	10	8.5833	8	NA / 2	NA / 8%	No	Evaluated	Full
15330005	6	pH	24 / 3	8.63	8.32	8.34	0 / NA	0% / NA	No	Evaluated	Full
15330005	6	Temperature	24 / 3	17.2	11.0042	11.5	0 / 0	0% / 0%	No	Evaluated	Full

Class BCW1 – Trout Natural Reproduction:

Based on the January 2021 summary of trout reproduction in Iowa streams prepared by the DNR Fisheries Bureau, the Class BCW1 coldwater aquatic life use of Grannis 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.

Class HH - No Data

Monitoring and Methods

Assessment Key Dates

4/4/2012

Non-fixed Monitoring Start Date

11/6/2014

Non-fixed Monitoring End Date

1/1/2021

Biological Monitoring

Methods

120

Surveys of fish and game biologists/other professionals

220

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

330

Fish surveys

420

Indicator bacteria monitoring