People interested in the temperature and amount of water in the Madison River are going to have a new steady source of information this spring and summer.
After a 40-year hiatus, the U.S. Geological Survey stream gauge at Varney Bridge south of Ennis is back online.
The new gauge is the result of a multi-faceted partnership between the Madison River Foundation, Montana Bureau of Mines and Geology, PPL Montana, the Madison Conservation District and the USGS.
The main benefit of the gauge will be simply to provide data to help people make better decisions about managing the river, said Sunni Heikes-Knapton, Madison Watershed Coordinator.
“You can’t make decent management decisions without decent information,” she said.
The USGS operates more than 200 stream gauges around the state, said surface water specialist Wayne Berkas. The oldest gauge is on the Missouri River at Fort Benton and has been operating since the 1880s.
Stream gauge information provides an historic record of stream flows and temperatures, which can provide important data about floods, droughts and the relationship between water levels and river health.
“A long, historic record is really nice to have,” Berkas said.
The Varney gauge was first set up in 1952 and operated until 1963. It was back on line from 1968 to 1970 and hasn’t run since.
The only other active stream gauge between Hebgen Lake and Ennis Lake is just upstream of where the West Fork of the Madison hits the main river.
“If you look at what we know about river flows, we had no information at all from the gauge above the West Fork at the old Kirby place to down stream to Madison Dam,” said Richard Lessner, executive director for the Madison River Foundation.
That fact became important a couple of summers ago when PPL Montana, which operates Hebgen and Madison Dam, pulsed flows out of Hebgen Lake in an effort to keep water in Ennis Lake and temperatures in the river cooler below Madison Dam. However, the water PPL pulsed out of Hebgen Lake wasn’t showing up in Ennis Lake and no one really knew why, Lessner said.
With the Varney gauge operating, PPL will be able to better track how their flows out of Hebgen impact the river near Ennis, he said.
The gauge will also help scientists figure out how groundwater near the river impacts stream flows and vice versa, Heikes-Knapton said.
The Montana Bureau of Mines and Geology is currently doing a groundwater study below Ennis Lake, she said. The data collected by the Varney gauge will help them track the water inputs into the river and how that impacts groundwater downstream.
The gauge will also be useful for help correlating river flows with other surface water features in the area, Heikes-Knaption said.
The gauge is located on land owned by the Granger Ranch, which is involved in restoring the upper reaches of O’Dell Creek on their land.
For instance, will high flows in O’Dell Creek occur at the same time as high flows in the Madison River or will fluctuation in flows in the Madison River result in a fluctuation of flows in O’Dell Creek.
The gauge will operate for about eight months out of the year at a cost of about $11,000 annually, Berkas said. Getting the station up and going this year was about $13,600 and the Madison Conservation District and their partners donated $7,600 and the USGS came to the table with $6,000, he said.
Access to the information generated by the gauge will be posted online at mt.water.usgs.gov.