Water Resources Monitoring in the Yellowstone River at Corwin Springs, Montana, 2022

The Greater Yellowstone Inventory and Monitoring Network monitors water quality and analyzes river discharge (flow) in the Yellowstone River each year. The river has relatively high water quality. It is ecologically important in the region and a popular cold-water fishery destination.

Upstream view from the monitoring location on the Yellowstone River at Corwin Springs, Montana, in October 2022.

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The Yellowstone River Site

The Yellowstone River, a tributary of the Missouri River, is the longest undammed river in the lower 48 states at 1,080 km (671 mi). Headwaters begin in the Absaroka Range from its North Fork on Younts Peak, Wyoming. It flows northwest through Yellowstone National Park, where it feeds and drains Yellowstone Lake and runs through Yellowstone Falls and the Grand Canyon of the Yellowstone. The river then exists the park near Gardiner, Montana (Figure 1 and Figure 2).

The Yellowstone River supports a variety of agricultural, municipal, and recreational uses, as well as ecological processes that are vital to the region. For example, the Yellowstone River headwaters and tributaries attract anglers as a cold-water fishery destination. Downstream, the river is a source of irrigation water for agriculture and drinking water for municipalities, including Laurel and Billings, Montana, and towns eastward into North Dakota.

The Greater Yellowstone Inventory and Monitoring Network monitors water quality and discharge (flow) in the Yellowstone River at Corwin Springs, Montana. This monitoring station is located 12 km (7.5 mi) downstream from Gardiner, Montana, and the Yellowstone National Park boundary. A 14 km (8.7 mi) segment (MT43B001_011) of the Yellowstone River within the park from the Wyoming border to the park boundary and a 7.7 km (4.8 mi) segment (MT43B001_010) from the park boundary to Reese Creek were listed in Section 303(d) of Montana's 2018 Water Quality Integrated Report (MTDEQ 2019). The 14 km segment was listed for ammonia, copper, nitrate + nitrite as N (NO3 + NO2 as N), sediment, and arsenic levels that exceed state drinking water standards. Both listed segments of the Yellowstone River are upstream of our water monitoring location.

Figure 1. Yellowstone River watershed boundary for the water monitoring location at Corwin Springs, Montana.

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Figure 2. An overview of the Yellowstone River monitoring location (denoted by the yellow star) relative to the Yellowstone National Park boundary and the city of Gardiner, MT.

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Water Flow in the Yellowstone River

The U.S. Geological Survey (USGS) operates a gaging station (USGS Gage 06191500) on the Yellowstone River at Corwin Springs, MT, and has daily flow data dating back to 1890. A portion of the discharge record spanning from 1894 to 1910 is missing.

The Yellowstone River shows a characteristic snow-driven hydrograph, where average peak flows are greater during spring runoff compared to other times of the year. The average of annual peak flows between 1890 and 2021 is 16,747 cubic feet per second (cfs), occurring on average on 8 June (day 159 of the year; Figure 3). Minimum annual daily flows over this same period of record averaged 651 cfs.

In June of 2022, the Yellowstone River and its tributaries, including those throughout Yellowstone National Park’s Northern Range, experienced a 500-year flooding event. Water flows in the Yellowstone River in 2022 tracked with the long-term mean (1890–2021) until mid-June, when the combination of heavy rainfall and warming overnight temperatures accelerated snow melt on already-saturated soils. The resulting flood produced discharge values 17,000 cfs higher than the previous record (Marrs et al 2022) since records began in 1890. Flows peaked at 43,300 cfs on 13 June (day 164 of the year; Figure 3).

Precipitation records indicate that this location experienced at least double the amount of precipitation compared to the 30-year average (1991–2020) in the ten weeks prior to the flooding (April through June). In July, precipitation was 50% below the 30-year average (Figure 4). Despite this unprecedented flooding, the Yellowstone River at Corwin Springs flow values returned to the historical average (1890–2021) by July and dropped below the historical average (1890–2021) by August 2022. Minimum flow in 2022 was 382 cfs.

Figure 3. Summary of the average daily discharge (in cfs) in the Yellowstone River at Corwin Springs, Montana (USGS 06191500), for calendar year 2022 and for the period of record (1890–2021). The 25th and 75th percentiles of daily discharge are also presented.

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Figure 4. Calendar year 2022 monthly air temperature and precipitation departures from 30-year averages (1991–2020) at Mammoth, Montana (COOP Station ID 243378).

Figure was constructed using www.climateanalyzer.org

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Downstream view at the monitoring location on the Yellowstone River, June 2022.

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Water Quality in the Yellowstone River

The Yellowstone River has relatively high water quality and much of the watershed upstream from the monitoring location is managed within federal lands. We sampled the Yellowstone River for water chemistry and core water quality parameters eight times from March to November in 2022. Core water quality parameters include temperature, specific conductance, dissolved oxygen, pH, and turbidity.

Water chemistry contained low levels of dissolved nutrients. Ammonia as nitrogen (NH₃ as N) was below detection levels on all sampling dates except on 23 March and 21 November 2022 when concentrations of 0.11 mg/L and 0.18 mg/L were detected, respectively (reporting limit is 0.05 mg/L). Nitrate + nitrite as nitrogen (NO₃ + NO₂ as N) levels were between < 0.01 mg/L and 0.28mg/L and averaged 0.11 mg/L across all sample dates (reporting limit is 0.01 mg/L). Total suspended solids (TSS) and total phosphorus (P) concentrations tend to be higher with higher flows (Figure 5 and Figure 6). TSS and total P concentrations were at their annual maxima during the 16 June 2022 sampling event, which occurred three days after the historic flood on 13 June 2022.

Additional analytes were tested on the samples collected on 28 June 2022 following the flood on 13 June 2022. At that time, total petroleum hydrocarbons (TPH) were below the detection levels (reporting limit is 1 mg/L). TPH represent several hydrocarbons derived from crude oil, including the constituents of gasoline. Coliform bacteria (E. coli) were present at 10 CFU per 100 mL, a level regarded as “unsafe” by the Montana Department of Environmental Quality. E. coli contamination can indicate the water supply has been in contact with human or animal sewage. More information about E. coli can be found here.

Figure 5. Daily discharge (in cfs; solid line) in the Yellowstone River at Corwin Springs, Montana (USGS Gage 06191500), in 2022 shown with concentrations of total suspended solids (brown circles) summarized from water collected during 2022 monthly sampling.

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Figure 6. Daily discharge (in cfs; solid line) in the Yellowstone River at Corwin Springs, Montana (USGS Gage 06191500), in 2022 shown with concentrations of total phosphorus (orange circles) summarized from water collected during 2022 monthly sampling.

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Trace metals (such as arsenic, zinc, mercury, and lead) have been detected and are often naturally present at measurable concentrations in Yellowstone National Park waters (Elliott and Hektner 2000). Total arsenic concentrations tend to be lower with higher flows. In 2022, total arsenic levels in the Yellowstone River at Corwin Springs did not exceed the Montana chronic aquatic life criteria (0.15 mg/L) but did exceed human health surface water standards (0.010 mg/L; Figure 7). Due to arsenic naturally originating in Yellowstone National Park (Planer-Friedrich et al. 2007), Montana DEQ has determined a separate annual median nonanthropogenic arsenic standard for the Yellowstone River. On the segment of the Yellowstone River from the Montana/Wyoming border to Mill Creek, in which the Corwin Springs sampling location is monitored, this standard is 0.028 mg/L (MTDEQ 2019a, b; MTDEQ 2020).

Figure 7. Daily discharge (in cfs; solid line) in the Yellowstone River at Corwin Springs, Montana (USGS Gage 06191500), in 2022 and concentrations of total arsenic (circles) summarized from water collected during 2022 monthly sampling. The black, dotted line is the MTDEQ nonanthropogenic annual mean flow criterion (0.028 mg/L). MTDEQ aquatic life chronic criterion is the solid, black line (0.15 mg/L). The black, dashed line is the MTDEQ human health surface water criterion (o.010 mg/L).

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Water temperature is monitored continuously by the USGS at the Corwin Springs station (USGS Gage 06191500). Daily water temperature averages in 2022 tracked with the average daily water temperatures in the previous five years (2017–2021) until late July, when temperatures rose above the five-year average (Figure 8). The maximum daily water temperature reached in 2022 (21.9°C) was 1°C above the average daily maximum water temperature from 2017–2021 (20.9°C; Figure 9). Montana Fish, Wildlife and Parks regulates cold water fishing closures when water temperatures exceed 73.0°F (22.8°C) at any time of the day for three consecutive days (Montana Rule 12.5.507). The maximum temperature recorded in 2022 at the Corwin Springs station was 21.9 °C on 11 August (day 223 of the year).

Figure 8. Summary of the average daily water temperature in the Yellowstone River at Corwin Springs, Montana (USGS Gage 06191500), in 2022 and for 2017–2022.

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Figure 9. Summary of the daily maximum water temperature in the Yellowstone River at Corwin Springs (USGS Gage 06191500) in 2022 and from 2017–2022. Current Montana Fish, Wildlife & Parks drought policy states that angling closures may be enacted to protect cold-water fish species when daily maximum water temperatures reach at least 73°F (22.8°C; represented by the dashed line) for three consecutive days or when flows drop below minimum levels.

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2022 Water Quality Results

Table 1 shows water quality lab results and Table 2 shows water quality field results for the Yellowstone River at Corwin Springs, MT, in calendar year 2022. All Data for current and previous years can be accessed in the NPS Data Store. Data can also be downloaded from the Water Quality Portal using "11NPSWRD_WQX-YELL_YS549.7M" as the SiteID in the "Advanced" menu.

Table 1. Water chemistry lab parameter results (in mg/L) for Yellowstone River at Corwin Springs, Montana. All samples were processed at Energy Laboratories in Billings, Montana. For results with a less than symbol (i.e., < 0.05), the number represents the reporting limit (in mg/L), which is the threshold value that many analystical labs consider to be the lowest reportable value for an individual analyte; the reporting limit may be higher than the detection limit, and the analyte may be present in the sample but at concentrations less than the lab reports on. Sampling events include regular samples (Reg) and replicate samples (Rep) for comparison. Field blanks were also performed and were processed using certified inorganic free deionized water. All field blank samples were below the detection limit and not reported here unless noted.

Table of water quality lab results for the Yellowstone River at Corwin Springs, Montana

Water Chemistry Lab Parameters	23 March Reg	02 May Reg	16 June Reg	16 June Rep	28 June Reg	01 August Reg	15 August Reg	04 October Reg	21 November Reg	21 November Rep

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Table 2. Water quality field parameter results for the Yellowstone River at Corwin Springs, Montana. These samples were collected onsite using a YSI Exo1 sonde, and each value represents an average of four measurements taken across the stream sampling width.

Table of 2022 water quality field parameters for the Yellowstone River at Corwin Springs, Montana.

Core Water Quality Field Parameter	23 March	02 May	16 June	28 June	01 August	15 August	04 October	21 November

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A crane, reel, and DH-95 suspension sampler are used to collect water samples when the river is non-wadeable. Photograph taken at the monitoring location on the Yellowstone River at Corwin Springs, Montana.

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Monitoring Methods

Water Chemistry

The Greater Yellowstone Inventory and Monitoring Network collects water samples monthly during ice-free periods generally following depth- and width-integrated protocols outlined in the U.S. Geological Survey (USGS) National Field Manual for the Collection of Water-Quality Data.

Samples are usually collected from a bridge-board or crane, reel, and DS-95 suspension sampler. In wadeable depths and low flow, we use a 1 L, hand-held DH-81 sampler affixed to a 1 m wading rod. At multiple locations along a cross section of the river we collect water using vertically integrated sampling techniques. Samples from the 1 L bottle are mixed into an 8 L churn splitter; we use the churn splitter to homogenize and dispense a representative subsample into laboratory-provided bottles. These bottles are then shipped overnight to an EPA-certified commercial lab for processing.

A handheld, multi-parameter instrument is used to collect water quality parameters: temperature, specific conductance, dissolved oxygen, pH, and turbidity. This photograph was taken on the Lamar River in Yellowstone National Park.

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River Discharge

Discharge (river flow estimates) and water temperature data from the Yellowstone River sampling location are available online from the U.S. Geological Survey's National Water Information System and listed under station USGS 06191500. The station is near Corwin Springs, MT.

Greater Yellowstone Network Water Resources Protocols

Read the full protocols and standard operating procedures for water quality and discharge here.

Protocols and Standard Operating Procedures

Source: Data Store Collection 7853. To search for additional information, visit the Data Store.

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Water Quality Criteria for the Yellowstone River

Under the Clean Water Act, the surface waters in Yellowstone National Park are classified as Outstanding National Resource Waters. Under the Montana Water Classification System, these waters, located wholly within national park boundaries, are designated as A-1, or Outstanding Resource Waters in Montana (Administrative Rules of Montana 17.30.617). Exiting the park at Gardiner, MT, the Yellowstone River has been classified as B-1. Water bodies classified as B-1 are suitable for drinking (after conventional treatment); full contact recreation; growth and propagation of salmonid fishes and associated aquatic life; waterfowl; and furbearers; and agricultural and industrial water supply.

Yellowstone River water quality monitoring results are compared to the following federal and state water quality standards:

EPA National Recommended Water Quality Criteria

Environmental Protection Agency (EPA). 1987. Quality criteria for water 1986 [The Gold Book]. EPA440/5-86-001. U.S. EPA, Office of Water Regulations and Standards, Washington D.C.

Montana Numeric Water Quality Standards – MT DEQ Circular DEQ-7

Administrative Rules of the State of Montana 17.30.617: OUTSTANDING RESOURCE WATERS -- DESIGNATION

Montana Department of Environmental Quality Final 2020 Water Quality Integrated Report

Montana Department of Environmental Quality, Demonstration of Nonanthropogenic Arsenic Levels: Yellowstone River, Montana (2019)

Montana Department of Environmental Quality, Derivation of the Nonanthropogenic Arsenic Standards for Segments of the Upper and Middle Yellowstone River (2019)

Montana Department of Environmental Quality, Addendum to Derivation of the Nonanthropogenic Standards for Segments of the Upper and Middle Yellowstone River (2020)

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Past Findings

2021 Water Resources Monitoring in the Yellowstone River at Corwin Springs, MT
2019 Water Resources Monitoring in the Yellowstone River at Corwin Springs, MT

Citations

Elliott, C. R., and M. M. Hektner. 2000. Wetland resources of Yellowstone National Park. Yellowstone National Park, Mammoth, Wyoming.

Mars, A. T. Rautu, D. Thoma, A. Rodman, M. Tercek, and A. Ray. 2022. When the River Breaks. Park Science, Volume 36, Number 2, Winter 2022.

Montana Department of Environmental Quality (MTDEQ). 2019a. Demonstration of nonanthropogenic arsenic levels: Yellowstone River, Montana. Helena, MT: Montana Dept. of Environmental Quality

Montana Department of Environmental Quality (MTDEQ). 2019b. Derivation of the nonanthropogenic arsenic standards for segments of the upper and middle Yellowstone River. Helena, MT: Montana Dept. of Environmental Quality.

Montana Department of Environmental Quality (MTDEQ). 2020. Addendum to derivation of the nonanthropogenic standards for segments of the upper and middle Yellowstone River. Helena, MT: Montana Dept. of Environmental Quality.

Planer-Friedrich, B., J. London, R. B. McCleskey, D. K. Nordstrom, and D. Wallschläger. 2007. Thioarsenates in geothermal waters of Yellowstone National Park: Determination, preservation, and geochemical importance. Environmental Science & Technology 41: 5245–5251.

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Article created by the Greater Yellowstone Inventory and Monitoring Network, 2024.