Water samples are collected from major rivers in Yellowstone National Park on a regular basis. Measurements of the chloride concentrations provide an estimate of the total heat discharge from the Yellowstone volcanic system. Changes in the chloride concentrations over time help scientists to understand how heat released from the subsurface relates to magmatic and tectonic activity.

Hydrologic Data from the U.S. Geological Survey

The USGS provides provisional real-time stream-flow data from the major rivers draining Yellowstone National Park. 

• Stream discharge and temperature at Tantalus Creek, Norris Geyser Basin, provides data that helps to verify eruptions of geysers within the basin.
• Provisional real-time stream-flow data of the major rivers draining Yellowstone National Park, provided by the USGS.

The map below includes the locations for gauge stations throughout the Yellowstone National Park area.
 

Map of gauge stations where stream-flow measurements are made around Yellowstone National Park. (Public domain.)

List of Gauge Stations by Area

1. Firehole River near West Yellowstone, YNP
2. Firehole River near Old Faithful, YNP
3. Gibbon River at Madison Junction, YNP
4. Madison River near West Yellowstone, YNP
5. Tantalus Creek at Norris Junction, YNP
6. Yellowstone River at Yellowstone Lake Outlet, YNP
7. Soda Butte Creek at Park Boundary at Silver Gate, YNP
8. Soda Butte Creek near Lamar Ranger Station, YNP
9. Lamar River near Tower Falls Ranger Station, YNP
10. Boiling River at Mammoth, YNP
11. Gardner River near Mammoth, YNP
12. Yellowstone River at Corwin Springs, MT
13. Henrys Fork near Ashton, ID
14. Falls River AB Yellowstone Canal, Near Squirrel, ID
15. Snake River AB Jackson Lake at Flagg Ranch, WY