Central City Ponds IA 01-WPS-348

Linn County S3T85NR6W near Central City.

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
View assessment methodology in new window

Cycle: 2020
Release Status: Final
Overall IR: 3 - Insufficient data exist to determine whether any designated uses are met.
Trophic: Unknown
Trend: Stable
Created: 9/3/2020 8:51:44 AM
Updated: 10/16/2020 1:11:29 PM

Use Support

Class BLW

Aquatic Life - Lakes and wetlands

Not Assessed

Class HH

Human Health -

WINOFI

Fish Consumption Advisory: PCBs

Support Level

Further Investigation Needed

Impairment Code

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

Cause Magnitude

Slight

Status

Continuing

Source

Unknown: Source Unknown

Source Confidence

N/A

Cycle Added

2010

Impairment Rationale

Potential fish consumption advisory; additional sampling needed

Data Source

Fish contaminant monitoring: Iowa DNR

General Use

General Use water -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class HH use remains assessed (evaluated) as "partially supported" based on results of fish contaminant monitoring. All other designated uses are “not assessed.”

Assessment Explanation

Sources of Data:

Data Source	Data Source ID	Data Type	Data Age	Site ID	Site Name	Site Description
Iowa DNR	6	FT	See Below	234	Central City Ponds

Class BLW – No Data

Class HH - Fish Tissue Sampling:

Site ID

Date

Species Name

Biopart

# in sample

chlordane result

chlordane violation?

PCBs result

PCBs violation?

Hg result

Hg violation?

Assessment Type

Support Level

234

7/30/07

largemouth bass

fillet

0.0788

Evaluated

Full

234

9/14/07

yellow bullhead

fillet

<0.13

<0.231

0.0526

Evaluated

Full

The level of total PCBs in the sample of yellow bullhead, however, exceeds the DNR/IDPH trigger level of 0.2 ppm for a one meal per week consumption advisory. The existence of, or potential for, a fish consumption advisory is the basis for Section 305(b) assessments of the degree to which Iowa’s lakes and rivers support their fish consumption uses. According to the DNR/IDPH advisory protocol, two consecutive samplings that show contaminant levels are above the trigger level in fillet samples are needed to justify issuance of an advisory. Thus, additional monitoring will be conducted at Central City Ponds to determine whether an advisory is needed for this waterbody. According to DNR’s assessment methodology, the occurrence of contaminant above an advisory trigger level suggests that “full support” of the fish consumption use is “threatened” and should be placed in category 3b.

Monitoring and Methods

Assessment Key Dates

9/14/2007

Fish Tissue Monitoring

7/30/2007

Fish Tissue Monitoring

Methods

150

Monitoring data more than 5 years old

260

Fish tissue analysis