2020 assessment for Hickory Creek

Hickory Creek IA 04-RAC-1141

mouth (S17 T79N R27W Dallas Co.) to confluence with unnamed tributary in S16 T79N R27W Dallas Co.

2020
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 2016 - 2018
Stream/River Water Quality Data	CY 2016 - 2018
Lake Water Quality Data	CY 2014 - 2018
Biological Sampling Data	CY 2014 - 2018*
Fish Kill Data	CY 2014 - 2018
Fish Tissue Sampling Data	CY 2014 - 2018
Continuous Dissolved Oxygen Sampling Data	CY 2014 - 2018
*Biological sites sampled in both 2013 and 2017 were also assessed.

Open Segment Map
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Overall IR

3 - Insufficient data exist to determine whether any designated uses are met.

Trend

Unknown

Created

10/7/2020 12:10:58 PM by

Updated

10/13/2020 9:58:04 AM by

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Assessed

Class BWW2

Aquatic Life - Warm Water Type 2

WINOFI

Biological

Support Level

Further Investigation Needed

Impairment Code

3b - Use potentially impaired based on an evaluated assessment.

Cause Magnitude

Moderate

303(d) Listing Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

1996

Impairment Rationale

Potential Impairment

Data Source

Special project/study: Iowa DNR

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 remains assessed as "partially supported" based historical biological sampling data and habitat assessment. All other designated uses were "not assessed".

Assessment Explanation

Presumptive Class A1 - No Data

Class BWW2 - Biological Sampling:

The aquatic life use was assessed as "partially supported" due to (1) relatively low diversity (7 species; 2 families) for streams in this (47b) sub-ecoregion, (2) presence of less than a majority of the expected fish taxa (5 of 11) for streams in this sub-ecoregion, and (3) indications on field sheet of relatively poor quality aquatic habitats despite the lack of significant threats to the physical characteristics of the river reach assessed. Additional sampling with more a more effective gear type is still needed to better determine the status of the aquatic communities. The field sheet from the 1994 assessment indicates the presence of relatively high quality aquatic habitats and field notes indicated that effective seining was hindered by rocks and snags.

Monitoring and Methods

Assessment Key Dates

5/10/1994

DNR Stream Use Assessment

Methods

150

Monitoring data more than 5 years old

330

Fish surveys