How the Park Service Samples the Madison River near West Yellowstone, Montana

The National Park Service's Greater Yellowstone Inventory and Monitoring Network samples the Madison River near West Yellowstone, Montana, every month while the river is free of ice. It generally follows the depth- and width-integrated methods of the U.S. Geological Survey's National Field Manual for the Collection of Water-Quality Data.

Collecting the water

• Wadeable flows. A 1-litre hand-held DH-81 sampler on a 1-metre wading rod.
• Too deep to wade. A DH-95 suspension sampler lowered on a reel from a bridge board or crane on the bridge.

Sampling from the bridge with a bridge board, reel and DH-95 suspension sampler when the Madison is too deep to wade. NPS.

Water is collected at several points across the river, each sampled through the full depth. The litre bottles are emptied into an 8-litre churn splitter, which mixes the water and dispenses a representative subsample into the laboratory's bottles. These go overnight to an EPA-certified commercial lab.

Readings in the river

At four representative points across the river, a hand-held multi-parameter instrument (for example, a YSI EXO 1 sonde) measures temperature, specific conductance, dissolved oxygen, pH and turbidity directly in the water. How these core measurements are taken, and why nutrients and suspended solids are tested, is set out in the network's approved regulatory water-quality monitoring protocol (O'Ney 2006).

A hand-held multi-parameter instrument in use on the Lamar River in Yellowstone National Park. NPS.

River flow

Discharge and water-temperature data for the sampling location are published by the U.S. Geological Survey's National Water Information System under station 06037500, east of West Yellowstone.

Sources

• National Park Service, Greater Yellowstone Inventory and Monitoring Network, "Water Monitoring Methods for the Madison River near West Yellowstone, Montana," part of Water Resources Monitoring in the Madison River near West Yellowstone, Montana, 2021. https://www.nps.gov/articles/000/madison-river-water-monitoring-methods.htm
• Protocols and standard operating procedures: NPS DataStore Collection 7853, https://irma.nps.gov/DataStore/Collection/Profile/7853
• O'Ney 2006, Greater Yellowstone Network Regulatory Water Quality Monitoring Protocol: https://irma.nps.gov/DataStore/Reference/Profile/628938
• USGS National Water Information System: https://waterdata.usgs.gov/nwis/uv