Snake River Water Quality at Moose, Wyoming

Water quality in the Snake River headwaters is considered very high quality and the river is valued for its natural, cultural, and recreational contributions to the region. We sampled the Snake River at Moose, WY, for water chemistry and core water quality parameters monthly from May to November in 2021. Core water quality parameters include temperature, specific conductance, dissolved oxygen, pH, and turbidity.

Results in 2021 were comparable to previous years and indicative of high-quality waters; samples contained low levels of dissolved and total nutrients. Trace metals such as arsenic, copper, and iron have been detected in the watershed and are naturally present in measurable concentrations. Fluctuations in these trace metals are driven by discharge during runoff. Total iron levels were greatest during times of peak flow in the month of May and exceeded the Wyoming Chronic Aquatic Life Criterion for total recoverable iron
(1 mg/L). Arsenic levels increase during low flow months but were detected in concentrations below the Wyoming Chronic Aquatic Life Criterion (0.15 mg/L).

Maximum daily water temperatures in summer 2021 exceeded the Wyoming Department of Environmental Quality surface water quality standards (WY DEQ 2018) guidance for cold water fish temperature (20°C or 68°F) on 20 days. Temperatures above 20°C were detected on 14 July and intermittent exceedances of 20°C extended through 15 August. Air temperatures during that same time averaged 29.7°C (85.4°F).

Daily discharge (in cfs; blue line) from USGS Gage 13013650 (Snake River at Moose, WY) shown with concentrations of total iron (Fe; circles) summarized from water collected during monthly sampling during 2021. The Wyoming Chronic Aquatic Life Criterion is represented by the horizontal black line (1.0 mg/L total extractable iron).

NPS

Daily discharge (in cfs, solid blue line) from USGS Gage 13013650 (Snake River at Moose, WY) shown with mean (orange dotted line) and maximum (brown dash and dotted line) daily water temperatures (°C) summarized from USGS water temperature data collected during snow-free periods of 2021. The Wyoming DEQ cold water fish criterion is represented by the horizontal dashed line (20°C).

NPS

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2021 Water Quality Lab Results

The following two tables contain water quality lab results for the Snake River at Moose, WY, from May through July and August through November, respectively. Download tabular data here for these tables.

Table 1. May through July 2021 monthly water chemistry lab results (in mg/L) for the Snake River below Jackson Lake at Moose, WY. All samples were processed at Energy Laboratories in Billings, MT. Reporting limit (in mg/L) is the threshold value that many analytical labs consider to be the lowest reportable value for an individual analyte; this value may be higher than the maximum detection limit. ND = non-detectable result. Naturally occurring exceedances of the Wyoming Chronic Aquatic Life Criterion are labeled with "EX" after the value. Values followed by an "H" indicate the analysis was performed after holding time for this analyte (e.g., ortho-phosphate has a 48-hour holding time) but within 24 hours of method holding times. Some sampling events included a replicate or blank sample where indicated; blank samples are processed using certified inorganic free deionized water. 

Monthly water quality lab results May to July 2021 for the Snake River at Moose, WY

Water Chemistry Lab Parameters (Snake River, Moose, WY) (mg/L)	Reporting Limit (mg/L)	5/17/2021	6/23/2021	7/19/2021	7/19/2021 Replicate Sample

Table 2. August through November 2021 monthly water chemistry lab results (in mg/L) for the Snake River below Jackson Lake at Moose, WY. All samples were processed at Energy Laboratories in Billings, MT. Reporting limit (in mg/L) is the threshold value that many analytical labs consider to be the lowest reportable value for an individual analyte; this value may be higher than the maximum detection limit. ND = non-detectable result. Naturally occurring exceedances of the Wyoming Chronic Aquatic Life Criterion are labeled with "EX" after the value. Values followed by an "H" indicate the analysis was performed after holding time for this analyte (e.g., ortho-phosphate has a 48-hour holding time) but within 24 hours of method holding times. Some sampling events included a replicate or blank sample where indicated; blank samples are processed using certified inorganic free deionized water. 

Monthly water quality lab results, August to November 2021 for the Snake River at Moose, WY.

Water Chemistry Lab Parameters (Snake River, Moose, WY) (mg/L)	Reporting Limit (mg/L)	8/13/2021	9/18/2021	9/18/2021 Replicate Sample	10/20/2021	11/9/2021	11/9/2021 Replicate Sample

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2021 Water Quality Field Results

Download tabular data here for this table.

Table 3. Monthly (2021) water quality field parameter results for the Snake River below Jackson Lake at Moose, WY.

Monthly water quality field results for the Snake River at Moose, WY.

Water Quality Field Parameters (Snake River, Moose, WY)	5/17/2021	6/23/2021	7/19/2021	8/13/2021	9/18/2021	10/20/2021	11//9/2021

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More Data

Data prior to 2016 are available at the Water Quality Portal using GRTEWQ01 for the project and 11NPSWRD_WQX-GRTE_SNR02 as the site identifier for the Snake River at Moose, WY.