Rock Creek IA 01-MAQ-3

from unnamed tributary in SW 1/4 NE 1/4 S30 T81N R6E Clinton Co. (upstream from PCS Nitrogen) to unnamed tributary in S23T81NR5E Clinton 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: 1 - All designated uses are met.
Trend: Stable
Created: 11/1/2023 8:13:11 AM
Updated: 1/29/2024 2:00:08 PM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Fully Supported

Class BWW2

Aquatic Life - Warm Water Type 2

Fully Supported

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class A1 use was assessed as "fully supported" based on water quality monitoring data. The Class BWW2 use was assessed as "fully supported" based on water quality monitoring data.

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
LTRMP	17	WQ	CY 2020-2022	99990002	Rock Creek, Camanche

PresumptiveClass A1 - Indicator Bacteria: No Data

PresumptiveClass A1 – pH:

Site ID	Data Source ID	# Samples / # Years	Minimum Value	Maximum Value	Mean Value	# Violations	Violations needed for impairment	Violates Significantly >10% Rule?	Assessment Type	Support Level
99990002	17	40 / 3	4.9	8	7.5	2	7	NO	Mon	Full

Class BWW2 - Binomial Parameters:

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Minimum Value	Maximum Value	Mean Value	# Violations	# Acute / Chronic Violations	Violations needed for impairment	Violates Significantly >10% Rule?	Assessment Type	Support Level
99990002	17	Dissolved Oxygen	40 / 3	7.4	14.5	10.3	0	NA / NA	7	NO	Mon	Full
99990002	17	pH	40 / 3	4.9	8	7.5	2	NA / NA	7	NO	Mon	Full
99990002	17	Temperature	40 / 3	0.7	22	13	0	NA / NA	7	NO	Mon	Full

Class BWW2 - Toxic Parameters:

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Maximum Value	Mean Value	Median Value	# Acute / Chronic Violations	>1 Acute / Chronic Violation	Assessment Type	Support Level
99990002	17	Ammonia	40 / 3	0.004	0	0	0 / 0	NO	Mon	Full

Monitoring and Methods

Assessment Key Dates

1/10/2020

Monitoring Start

11/9/2022

Monitoring End

Methods

200

Physical/Chemical Monitoring