Bennett Creek IA 02-IOW-6263

From confluence with unnamed tributary (T83N R15W Sec31 Tama County) to headwaters (T82N R16W Sec16 Tama County)

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 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.

Open Segment Map
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Cycle: 2022
Release Status: Final
Overall IR: 3 - Insufficient data exist to determine whether any designated uses are met.
Trend: Unknown
Created: 1/12/2022 6:26:01 AM
Updated: 1/12/2022 9:48:18 AM

Use Support

Class A2

Recreation - Secondary contact

WINOFI

Bacteria: Indicator Bacteria- E. coli

Support Level

Further Investigation Needed

Impairment Code

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

Cause Magnitude

Moderate

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2010

Impairment Rationale

Potential Impairment

Data Source

Ambient monitoring: USGS

Class BWW2

Aquatic Life - Warm Water Type 2

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A2 use was assessed (evaluated) as "WINOFI" based on levels of indicator bacteria (E. coli) that exceeded state water quality criteria and the number of samples. All other designated uses were "not assessed." Note 1: A TMDL covering the bacteria impairments for all segments, with the segment code prefix "IA 02-IOW" in the Iowa River Basin, was approved by EPA in 2018. Note 2: USGS issued a report in 2009 summarizing water quality for this stream and other streams sampled in 2006 on the Meskwaki Indian Reservation (see http://pubs.usgs.gov/sir/2009/5105/).

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
USGS	11	WQ	CY 2006	05451773	Bennett Creek near Tama

Class A2 - Indicator Bacteria: Original assessment data updated to A2 criteria and assessed accordingly. The A1 E. coli (4a) impairment was moved to the (3b) WINOFI list under the A2 criteria.

Site ID	Data Source ID	# Samples / # Years	2006 Geometric Mean	Annual Geometric Mean Violation	# Violations	% Violations	Significantly >10% Violations	Assessment Type	Support Level
05451773	11	6 / 1	2564	Yes	3	50%	NA	Evaluated	WINOFI

Class BWW2 – No Data

Monitoring and Methods

Assessment Key Dates

4/24/2006

Non-fixed Monitoring Start Date

12/4/2006

Non-fixed Monitoring End Date

3/9/2018

TMDL Completed

Methods

150

Monitoring data more than 5 years old

240

Non-fixed station physical/chemical (conventional + toxicants)

420

Indicator bacteria monitoring