Riverton IA 05-NSH-1413

Fremont County S19T68NR41W 1 mi. NW of Riverton.

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.
Trend: Unknown
Created: 1/6/2022 2:19:38 PM
Updated: 2/17/2022 3:04:50 PM

Use Support

Class BLW

Aquatic Life - Lakes and wetlands

Fully Supported

Class HH

Human Health -

Not Assessed

Impairment Delistings

No delistings for this assessment cycle.

Documentation

Assessment Summary

The Class BLW use remains assessed as "fully supported” based on information from the DNR Wildlife Bureau. All other designated uses were “not assessed.” This assessment was the same as that developed for the previous assessment/listing cycles (not impaired).

Assessment Explanation

Class BLW -

The Class BLW aquatic life use remains assessed (evaluated) as "fully supported” based on results of previous assessments.According to the local DNR Wildlife Biologist, Riverton normally has very good water quality but can receive considerable sedimentation from extremely heavy local rains. This wetland can also be inundated from high river flows in the East Nishnabotna and/or West Nishnabotna rivers when extremely heavy rains occur higher in their watersheds. Based on this information, the previous identification of "siltation" as impairing the aquatic life uses of this wetland was potentially an error. The assessment category for this wetland is "evaluated." In terms of Section 305(b) reporting, "monitored assessments" are based primarily on recent, site-specific ambient monitoring data and thus have relatively high confidence. "Evaluated assessments" are those based on data older than five years or other than site-specific ambient monitoring data (e.g., desktop models or questionnaire surveys of fish and game biologists [=best professional judgment]) and thus have relatively lower confidence.

Class HH - Fish Tissue sampling: No Data

In general, Iowa wetlands are not managed for recreational fisheries; thus, fish contaminant monitoring is not typically conducted at these waterbodies.

Monitoring and Methods

Assessment Key Dates

None listed

Methods

120

Surveys of fish and game biologists/other professionals