Lytle Creek IA 01-NMQ-95

mouth (Jackson Co.) to confluence with Buncombe Creek in S24 T87N R1E Dubuque 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 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
View assessment methodology in new window

Cycle: 2024
Release Status: Final
Overall IR: 3 - Insufficient data exist to determine whether any designated uses are met.
Trend: Unknown
Created: 11/1/2023 8:12:46 AM
Updated: 12/4/2023 10:45:43 AM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Assessed

Class BWW1

Aquatic Life - Warm Water Type 1

WINOFI

Biological: loss of native mussel species

Support Level

Further Investigation Needed

Impairment Code

3b-c - Use potentially biologically impaired based on calibrated IBI metrics.

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2002

Impairment Rationale

Loss of >50% of native mussel species

Data Source

Special project/study

Class HH

Human Health -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class BWW1 use was assessed as "WINOFI" based on results of a 1998-99 statewide assessment of freshwater mussels in Iowa streams. 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	22	Lytle Creek	Zwingle

Presumptive Class A1 – No Data

Class BWW1 - Biological Sampling:

Benthic Macroinvertebrates:

Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	BM Sample Gear	BMIBI score	BMIBI Class	47f BMIBI BIT	BMIBI Pass/Fail
22	7/21/20	57.3	47f	MS	Hess	56	Good	51	Pass

Fish:

Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage	Riffle Stream?	FIBI score	FIBI Class	47f FIBI BIT	FIBI Pass/Fail
22	9/30/22	57.3	47f	MS	NA	60	Good	36	Pass
22	7/21/20	57.3	47f	MS	NA	52	Good	36	Pass
22	7/26/19	57.3	47f	MS	NA	44	Fair	36	Pass

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Evaluated	Pass (1/1)	Full
Fish	Monitored	Pass (3/3)	Full	1	Assessment was monitored because the assessment used multiple
Overall	Monitored	Pass	Full		samples collected in the last five years.

Class BWW1 – Freshwater Mussel Sampling:

Freshwater Mussel Survey	# Freshwater Mussel Species	Avg. # Freshwater Mussel Species Increase/Decrease	Avg. % Freshwater Mussel Species Increase/Decrease	Assessment Type	Support Level	IR Category
1984-85 (Frest 1987)	3
1998-99 (Arbuckle et al. 2000) 3 sites	0	-3	-100%	Evaluated	WINOFI	3bc
As presented by Arbuckle et al. (2000), the potential causes of declines in species richness of Iowa's freshwater mussels include siltation, destabilization of stream substrate, stream flow instability, and high instream levels of nutrients (phosphorus and nitrogen). Their study also suggested the importance of stream shading provided by riparian vegetation to mussel species richness.

Class HH – No Data

Monitoring and Methods

Assessment Key Dates

9/30/1984

Biological Monitoring

9/30/1999

Biological Monitoring

9/30/2022

Biological Monitoring

7/26/2019

Biological Monitoring

7/21/2020

Biological Monitoring

7/22/2020

Biological Monitoring

Methods

120

Surveys of fish and game biologists/other professionals

150

Monitoring data more than 5 years old

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

330

Fish surveys