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Water Monitoring


The Upper Yellowstone Watershed is infrequently tested for water quality and, when it is, it is tested in very few locations. In response, the local community and scientists are coming together to test water quality for themselves, and share that information for the public good. In commemoration of the 2016 fish kill, in July 2018, we launched what we believe is the largest water quality test on a stretch of a community of average Joe's and Jane's. The protocol we use has been created by the scientific community in conjunction with state and federal agencies and we publish it here for feedback and educational purposes. Most importantly, we provide the data itself at no cost to the public.

Show me the Data!

PROVISIONAL DATA, SUBJECT TO REVISION: data are provisional and subject to revision until they have been thoroughly reviewed and received final approval. Provisional data may be inaccurate due to instrument malfunctions. Subsequent review based on field inspections or quality control measures may result in significant revisions to the data. Data users are cautioned to consider the provisional nature of the information before using it for decisions that concern personal or public safety or the conduct of business that involves substantial monetary or operational consequences. Raw data files may be obtained by emailing

Interpreting the Data

There are many ways to use the above data, in conjunction with other data sets, in order to understand the water quality health of the watershed. Here are just a few:

Orthophosphates (or Reactive Phosphorus) (more info at and

  • 0.01 - 0.03 mg/L: the level in uncontaminated water

  • 0.025 - 0.1 mg/L - level at which plant growth is stimulated

  • 0.1 mg/L - maximum acceptable to avoid accelerated eutrophication

  • > 0.1 mg/L - accelerated growth and consequent problems

Ammonia (more info at

  • NH3 is the principal form of toxic ammonia. It has been reported toxic to freshwater organisms at concentrations ranging from 0.53 to 22.8 mg/L. Toxic levels are both pH and temperature dependent. Toxicity increases as pH increases and as temperature increases. Plants are more tolerant of ammonia than animals, and invertebrates are more tolerant than fish. Hatching and growth rates of fishes may be affected. In the structural development, changes in tissues of gills, liver, and kidneys may also occur. Toxic concentrations of ammonia in humans may cause loss of equilibrium, convulsions, coma, and death.

  • Rainbow trout fry can tolerate up to about 0.2 mg/L while hybrid striped bass can handle 1.2 mg/L.

Nitrates (more info at

  • Indirectly effects aquatic organisms. Higher nitrate concentrations contribute to increases in algae blooms which then decreases the amount of dissolved oxygen needed by aquatic insects, fish and amphibians.


pH (more info at

  • Optimal range in the Upper Yellowstone watershed is a pH between 6-8

  • Harmful effects become noticeable for e.g. trout when the pH of water falls below 5.0 or rise above 9.6

Dissolved Oxygen (more info here)

  • Water temperature and atmospheric pressure affect the capacity of water to hold dissolved oxygen. Cold water at high atmospheric pressure holds more dissolved oxygen than warm water at low atmospheric pressure. Oxygen levels also are affected by the degree of light penetration (turbidity, color and water depth) and the degree of water turbulence or wave action. Dissolved oxygen (D.O.) is reported as milligrams of oxygen per liter of water (mg/L) which can be called parts by weight per million (ppm).

  • Trout and stoneflies, for example, require high dissolved oxygen levels. Trout need water with at
    least 6 mg/L D.O. Warm water fish like bass and bluegills survive nicely at 5 mg/L D.O. and some organisms like carp and bloodworms can survive on less than 1 mg/L D.O.  The oxygen demand of aquatic plants and cold-blooded animals also varies with water temperature.  A trout uses five times more oxygen while resting at 80˚ F (26.7˚ C.) than at 40˚ F (4.4˚ C).

For a detailed guide to interpreting Water Quality Data see this report from Rutgers. For more information on the impact of water quality to agricultural irrigation see this study from Penn State's extension.

Testing Protocols

Field Technicians, fly fishing guides, local citizen scientists and students collected samples from the following major locations on the Yellowstone River (bold) and tributaries (bullets) on the Upper Yellowstone Watershed.

Corwin Springs

Carter's Bridge

Ninth Street - Yellowstone Angler

Big Creek Diversion

Tom Miner Creek

Six Mile Creek

Eight Mile Creek

Gardiner River

Grey Owl

Mallard's Rest 

Pine Creek Stem

Dan Bailey / Paradise Campground - Angler's West

Sphinx Creek

Rock Creek

Little Trail Creek

Landslide Creek 

LaDuke Spring 

Spring Creek

Bassett Creek

Mulherin Creek

Cedar Creek

Slip and Slide Creek

Joe Brown Creek

Donahue Creek

Big Creek

Dry Creek 

Goldmeyer Creek

Reedfly Farm Stem & Big Creek - Reedfly Farm

Fridley Creek 

Mill Creek - Sweetwater Fly Shop

Strawberry Creek @ East River Rd

McDonald Creek 

Pine Creek 

Deep Creek 

Pool Creek 

Suce Creek @ East River Rd

Airport Stem Sample 

Pine Creek by trailhead

Big Creek & Dry Creek - Mountain Sky

Emigrant Gulch Pre-Diversion

Strawberry Creek

Suce Creek

Emigrant Creek - Sage Lodge

Emigrant Creek at East River Road

Sheep Creek

How To Collect Samples

How To Collect Samples

Tributary Grab Sample Protocols

  • When retrieving samples from the mouth of the any given tributary it is crucial that these samples not be contaminated or influenced by flowing water of the Yellowstone.

    • Samples should be taken at least 10 feet from any water flowing in the main stem of the river.

    • Avoid taking samples in any back-eddies, seams, or mixed water.

  • Taking the Sample

    • First locate the place you will take the sample. Try and find a location that meets the above parameters as well as in a representative area of the tributary mouth (center of trib. from each bank)

    • Second, rinse the entire jar with the water flowing in the tributary.

    • Thirdly, make sure that your footing is not stirring up any sediment or contaminating the sample area.

    • Finally dip the entire jar into the tributary and retrieve sample by filling jar fully underwater then tilting and raising it from the water simultaneously.

    • Screw on cap tightly.

  • Recording Information

    • Either in a smart phone or notebook, record the tributary that you just sampled and the time (hh:mm) and date (MM-DD-YY).

    • If you have a thermometer, please record the initial temperature of the water sample.


Main Stem Grab Sample Protocols

  • Individuals taking grab samples at main stem locations will use the same process of collection as the tributary samples, besides the fact that the sample will be main stem water.

  • The only difference is the individual will be reaching over the side of the boat to collect the sample instead of exiting the boat and walking into the tributary.

  • Refer to Tributary Grab Sample Protocols above for specific sampling techniques.


Transportation of Samples

  • If transporting by car, samples must be kept in a cooler with no ice and transported to either “26” FAS or Emigrant FAS drop off sites.

  • Transportation by boat is still TBD. Testing of the best method is currently underway.


Pickup / Drop Off Site Protocols

  • Drop sites will be at every fishing access site/ pull off between the mouth of the Gardiner River and Carters Bridge.

    • These drop sites will be marked with a wooden steak painted orange.

    • These sites will be within 100ft of the boat ramps/ pull offs.

  • Dropping the Sample

    • Individuals dropping off a sample will locate orange marker.

    • Perpendicularly to the marker, the sample will be sunk under the water by placing a rock in the mesh bag with the sample container.

      • This is done so that the water sample maintains its temperature while waiting to be transported to the lab.

    • Where the sample is placed should be in a safe location where samples will not float away, be crushed, taken, etc.  

  • Once sample is secure, send a verification text to the YERC technicians including the information that you recorded:  Tributary/time/ date/ temperature (if taken).

Have Questions? Call YERC Technicians Ryan Cornwall: Cell: (425) 677-4586, Abby Schmeichel: Cell: (717) 725-3011, or Tatiana Tilley: Cell: (214) 870-5171

Testing Samples

How To Test Samples

Tools of the Trade


Appendix: Tools

  • Collection Bottle

  • Hach Analyzer DR900

  • Reagents (Ph, Ammonia, Phosphates, Nitrates, Heavy Metals)

  • Analysis vile beakers (fits in to Hach Analyzer)

  • Pipette for transferring water from collection bottle to testing bottle

  • Internet Connection for uploading data from the Hach analyzer to the Microsoft Cloud

  • Microsoft PowerBI for creating visual reports of the data stored on Microsoft's Cloud

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