DRAFT 2026 assessment for Waterman Creek

Waterman Creek IA 06-LSR-1620

mouth (S26 T94N R39W O'Brien Co.) to confluence with Epping Cr. in S36 T97N R40W O'Brien Co.

This is a DRAFT assessment

Draft assessments may change without notice

2026
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 2022 - 2024
Stream/River Water Quality Data	CY 2022 - 2024
Lake Water Quality Data	CY 2020 - 2024
Biological Sampling Data	CY 2020 - 2024*
Fish Kill Data	CY 2020 - 2024
Fish Tissue Sampling Data	CY 2020 - 2024
Continuous Dissolved Oxygen Sampling Data	CY 2020 - 2024
*Biological sites sampled in both 2019 and 2023 were also assessed.

Open Segment Map
View 2026 assessment summary page

Overall IR

5 - Water is impaired or threatened and a TMDL is needed.

Trend

Stable

Current Phase

Public Comment

Created

10/27/2025 3:10:13 PM by

Updated

1/7/2026 10:07:41 AM by

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Fully Supported

Class BWW2

Aquatic Life - Warm Water Type 2

Not Supported

Organic Enrichment: Low Dissolved Oxygen

Support Level

Not Supported

Impairment Code

5a - Pollutant-caused impairment. TMDL needed.

Cause Magnitude

Slight

303(d) Listing Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2024

Impairment Rationale

Significantly > 10% of days fail to meet 24-hour criteria

Data Source

Watershed project monitoring

TMDL Priority

Tier III

Biological: low aquatic macroinvertebrate IBI

Support Level

Not Supported

Impairment Code

5b-v - Biological - verified

Cause Magnitude

Moderate

303(d) Listing Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

Low

Cycle Added

2024

Impairment Rationale

Low Biotic Index

Data Source

Biological monitoring: Iowa DNR WQMA

TMDL Priority

Tier IV

303(d) Delistings for this Cycle

No delistings for this assessment cycle.

Documentation

Assessment Summary

The presumptive Class A1 use was assessed as “fully supported” based on pH monitoring data. The Class BWW2 use was assessed as “not supported” based on biological sampling data and water quality monitoring data.

Assessment Explanation

Data Sources:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	WQ	CY 2022-2022	12710006	Waterman Creek-Sutherland
Iowa DNR	6	WQ	CY 2022-2023	14000484	Waterman Creek
Iowa DNR	6	WQ	CY 2023-2023	14000569	Waterman Creek
Iowa DNR	6	BIO	See Below	255	Waterman Creek	Sutherland
Iowa DNR	6	BIO	See Below	1340	Waterman Creek	Waterman Prairie Complex (North)
Iowa DNR	6	BIO	See Below	1417	Waterman Creek	Waterman Prairie Complex (South)

Presumptive Class A1 - Indicator Bacteria: No Data

Presumptive Class 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
12710006	6	10 / 1	7.6	8.4	8	0	3	NO	MONITORED	FULL
14000484	6	9 / 2	7.7	8.4	8.1	0	3	NO	MONITORED	FULL
14000569	6	7 / 1	7.8	8.3	8	0	3	NO	EVALUATED	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
12710006	6	Dissolved Oxygen	10 / 1	3.87	14.45	8.29	3	NA / NA	3	YES	MONITORED	NOT
14000484	6	Dissolved Oxygen	9 / 2	6.3	13.3	9.5	0	NA / NA	3	NO	MONITORED	FULL
14000569	6	Dissolved Oxygen	7 / 1	6.2	10.3	8.5	0	NA / NA	3	NO	EVALUATED	FULL
12710006	6	pH	10 / 1	7.6	8.4	8	0	NA / NA	3	NO	MONITORED	FULL
14000484	6	pH	9 / 2	7.7	8.4	8.1	0	NA / NA	3	NO	MONITORED	FULL
14000569	6	pH	7 / 1	7.8	8.3	8	0	NA / NA	3	NO	EVALUATED	FULL
12710006	6	Temperature	10 / 1	8.265	25.425	19.871	0	NA / NA	3	NO	MONITORED	FULL
14000484	6	Temperature	9 / 2	16.4	28.7	20.4	0	NA / NA	3	NO	MONITORED	FULL
14000569	6	Temperature	7 / 1	19.2	26.6	22.4	0	NA / NA	3	NO	EVALUATED	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
12710006	6	Ammonia	9 / 1	0.13	0.05	0.02	0 / 0	NO	EVALUATED	FULL

Class BWW2 - Biological Sampling:

Benthic Macroinvertebrates:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage/ Thermal	BM Sample Gear	BMIBI score	BMIBI Class	47a BMIBI BIT	BMIBI Pass/Fail
1417	8/22/23	139.0	47a	MO/WW	Surber	56	Good	54	Pass
1340	8/21/23	130.0	47a	MO/WW	Surber	56	Good	54	Pass
1417	7/27/23	139.0	47a	MO/WW	Hess	49	Fair	54	Fail
1340	7/20/23	130.0	47a	MO/WW	Surber	53	Fair	54	Fail
1340	9/21/22	130.0	47a	MO/WW	Surber	43	Fair	54	Fail
1340	8/15/22	130.0	47a	MO/WW	Surber	50	Fair	54	Fail
1340	7/20/22	130.0	47a	MO/WW	Hess	50	Fair	54	Fail
255	7/19/21	125.1	47a	MO/WW	Surber	33	Fair	54	Fail

Fish:

BioNet Site ID	Date	Drainage Area (mi2)	Ecoregion	Major Drainage/ Thermal	Riffle Stream?	FIBI score	FIBI Class	47a FIBI BIT	FIBI Pass/Fail
1417	8/22/23	139.0	47a	MO/WW	NA	45	Fair	43	Pass
1340	8/21/23	130.0	47a	MO/WW	NA	43	Fair	43	Pass
1340	8/15/22	130.0	47a	MO/WW	NA	52	Good	43	Pass
255	7/19/21	125.1	47a	MO/WW	NA	35	Fair	43	Fail

Overall:

Community	Assessment Type	Assessment Result	Support Level	IR Category	Reason
Benthic Macroinvertebrates	Monitored	Fail (2/8)	Not
Fish	Monitored	Pass (3/4)	Full		Assessment was monitored because the samples used to complete
Overall	Monitored	Fail	Not	5bv	the assessment were collected in a recent five-year period.

Class BWW2- Continuous DO Monitoring:

Site ID	Data Source ID	# Days Monitoring (2022)	# Days Monitoring (2023)	DO Criteria Type	# 2022 Violations / Violations needed for impairment	# 2023 Violations / Violations needed for impairment	Violates Annual Significantly >10% Rule?	Assessment Type	Support Level
				24 hr	63/18	22/16	Yes
14000484		128	113	16 hr	63/18	22/16	Yes
				24 hr	NA	1/15	No
14000569	6		97	16 hr	NA	4/15	No	Monitored	WINOFI

Monitoring and Methods

Assessment Key Dates

8/22/2023

Biological Monitoring

7/19/2021

Biological Monitoring

7/20/2022

Biological Monitoring

8/15/2022

Biological Monitoring

9/21/2022

Biological Monitoring

5/3/2022

Monitoring Start

8/28/2023

Monitoring End

8/21/2023

Biological Monitoring

7/27/2023

Biological Monitoring

7/20/2023

Biological Monitoring

Methods

200

Physical/Chemical Monitoring

315

Regional reference site approach

320

Benthic macroinvertebrate surveys

330

Fish surveys