Rio Grande Creek IA 06-BSR-6458

from mouth (T98N R44W Sec2) to headwaters (T99N R44W Sec25 NE)

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: 1/7/2022 11:26:09 AM
Updated: 1/7/2022 11:29:19 AM

Use Support

Class A1

Presumptive Use

Recreation - Primary contact

Not Assessed

Class BWW1

Presumptive Use

Aquatic Life - Warm Water Type 1

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

Insufficient water quality information available to assess use support.

Assessment Explanation

Presumptive Class A1 - No Data

Presumptive Class BWW1 – Fish kill Assessment:

The presumptive Class BWW1 use previously resided in IR Category 3b based on the assessment developed for the 2011 fish kill. Because no additional fish kills were reported in this segment for at least 10 years post fish kill (2021), the IR Category for the fish kill assessment was changed from 3b to 3a (not assessed). DNR believes that any impact from the fish kill from which the impairment was based has likely dissipated.

Details about the 2011 fish kill can be found here:https://programs.iowadnr.gov/fishkill/Events/829

Monitoring and Methods

Assessment Key Dates

None listed

Methods

None listed