Dale Maffitt Reservoir IA 04-RAC-1119

Polk County S31T78NR25W at SW edge of Des Moines.

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: 2 - Some of the designated uses are met but there is insufficient data to determine if remaining designated uses are met.
Trophic: Mesotrophic
Trend: Stable
Created: 12/28/2021 1:07:49 PM
Updated: 2/1/2022 2:17:30 PM

Use Support

Class A1

Recreation - Primary contact

Fully Supported

Class BLW

Aquatic Life - Lakes and wetlands

Fully Supported

Class C

Drinking Water -

Not Assessed

Class HH

Human Health -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class A1 use remains assessed (monitored) as “fully supported.” The Class BLW use remains assessed as “fully supported.” In terms of nutrient condition and water transparency, this lake continues to demonstrate exceptional water quality. While the Class BLW assessment was evaluated, the class will remain "fully supported". 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	WQ	CY 2018-2020	22250002	Dale Maffitt Reservoir

Class A1 - Indicator Bacteria: No Data

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
22250002	6	9 / 3	8.2	9.7	8.6	1	3	NO	Evaluated	Full

Class A1 - Lake TSI's

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Minimum Value	Maximum Value	Median Value	Median TSI Violation?	Assessment Type	Support Level
22250002	6	Chlorophyll a TSI	9 / 3	15	59	36	NO	Monitored	Full
22250002	6	Secchi TSI	9 / 3	38	50	44	NO	Monitored	Full
22250002	6	Total Phosphorus TSI	9 / 3	34	46	37	NA	NA	NA
22250002	6	Inorganic suspended solids	9 / 3	0.6	4	0.7	NA	NA	NA

Class BLW - Conventional 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
22250002	6	Ammonia	9 / 3	0.0012	0.0172	0.01	NA	0 / 0	3	NO	Evaluated	Full
22250002	6	Dissolved Oxygen	9 / 3	7.3	10.1	8.3	0	NA / NA	3	NO	Evaluated	Full
22250002	6	pH	9 / 3	8.2	9.7	8.6	1	NA / NA	3	NO	Evaluated	Full
22250002	6	Temperature	9 / 3	21.5	28.9	26	0	NA / NA	3	NO	Evaluated	Full

Class C - Conventional Parameters:

Site ID	Data Source ID	Parameter Name	# Samples / # Years	Minimum Value	Maximum Value	Mean Value	Median Value	# Violations	Violates Significantly >10% Rule?	Assessment Type	Support Level
22250002	6	Inorganic nitrogen (nitrate and nitrite)	9 / 3	0.02	0.29	0.06	0.03	0	NO	Evaluated	Full
22250002	6	pH	9 / 3	8.2	9.7	8.6	8.4	1	NO	Evaluated	Full

Class HH: No Data

Monitoring and Methods

Assessment Key Dates

5/29/2018

Fixed Monitoring Start Date

8/24/2020

Fixed Monitoring End Date

Methods

120

Surveys of fish and game biologists/other professionals

222

Non-fixed-station monitoring (conventional during key seasons and flows)

340

Primary producer surveys (phytoplankton/periphyton/macrophyton)