Since the 1980s, Flathead Lake Biological Station ecologists and other researchers have been rigorously studying Nyack Flats, a remarkable floodplain brimming with prehistoric insects, some living underground

Story & photography by Butch Larcombe

It’s about 9 a.m. on a grand late-fall morning when Phil Matson steers the maroon-colored SUV off U.S. Highway 2, crosses the railroad tracks and pulls up to a wooden gate. Ahead is a hayfield, with a spectacular backdrop of larch-studded mountains.

On the map, this spot, about a 20-minute drive southeast of West Glacier, is known as Nyack Flats. To the scientists, researchers and others at the Flathead Lake Biological Station, this tight mountain valley bisected by the Middle Fork Flathead River is an ecological treasure.

Since the 1980s, the folks from the research station on Flathead Lake’s east shore have been making regular treks up to Nyack Flats, lured from the lake by what they say is one of the most biologically intact floodplains in the world. Due to the decades of research activity by the station crews and others from points far and wide, this remote area is also likely one of the most studied floodplains in the world.

The station maintains and monitors a string of 20 monitoring wells in the Nyack, scattered across miles of private and public land. The wells provide a glimpse into what lies beneath in the aquifer, a subterranean realm of water, gravel and mysterious bugs, some of which exist without light and little oxygen.

The bugs — stoneflies — are a focus of much of the floodplain research. The stoneflies are an indicator species, an environmental bellwether.

“If they are present in an area, then you have a pretty healthy, intact floodplain ecosystem,” says Rachel Malison, a stream ecologist and post-doctoral researcher at the biological station. She and others, including principal investigator Gordon Luikart, are in the midst of a four-year project studying the ecology and genetics of stoneflies in floodplain ecosystems. The study is being paid for by a grant from the National Science Foundation.

Matson uses a laptop computer to download information from a sensor pulled from a monitoring well.

Malison oversees a team that spends six months a year at a camp on the floodplain, sleeping in canvas wall tents and gathering stoneflies from the Middle Fork, the connected aquifer and other sites, including Glacier National Park and the North Fork of the Flathead.

As Malison and other researchers note, the broader Glacier area is not the only place where stoneflies are found. But with its natural river flows, surrounding wilderness and a floodplain largely unaffected by development, the Nyack, unlike spots in Alaska or in the lofty reaches of Glacier, is more easily studied and has a long history of research, boosting its scientific value.

Despite being largely surrounded by tall peaks and wild land, the Nyack is, at least relatively, not remote. Hundreds of cars, trucks, motor homes and other vehicles zip through the valley on Highway 2, even when it’s not tourism season.

Parallel to the highway are the rails of the BNSF Railway main line that crosses northern Montana, connecting Chicago, the Twin Cities and the oilfields of North Dakota with the West Coast cities of Seattle and Portland. One some days, dozens of trains rumble through the Nyack, ferrying all sorts of cargo, including crude oil, a fact that concerns researchers and some Flathead-area residents. If even a few of those oil-hauling tanker cars were to tumble into the Middle Fork, a spill could wreak far-reaching environmental havoc.

But so far, the stoneflies don’t seem to be bothered by the highway or rail traffic. Researchers have identified 40 to 50 species in the Middle Fork itself and, remarkably, six or more species that live only below ground in the aquifer, often with very little oxygen. How those mysterious invertebrates exist and adapt to changing conditions is a focus of the stonefly project.

A BNSF Railway train made up of tanker cars rumbles through the Nyack. Researchers and others fear the impact of a possible spill from the tanker cars.

The study of stoneflies in the Nyack and elsewhere in the region got its start with Jack Stanford, the long-time director of the biological station, who retired a couple of years ago. Back in the 1980s, Stanford was poking around U.S. Forest Service property in the Nyack, armed with a drilling rig.

Ruth and John Dalimata, whose family has lived in the area since 1941, recall spotting the drilling activity. “John went over to see what he (Stanford) was doing it and that’s how it got started.” The “it” is the drilling of monitoring wells on the Dalimata property and eventually a lease agreement that allows station personnel and others to access the property for research purposes. Another private landowner in the Nyack has a similar agreement. The station has also reached an agreement with the Forest Service for the placement and monitoring of wells.

The Middle Fork in the Nyack area has long been designated a federal Wild and Scenic River. There are plenty of people interested in the river and its environment, including the Dalimatas.

“Jack (Stanford) found and identified a prehistoric bug out there while he was pumping out his wells,” Ruth recalls. “We called them hellgrammites. He called them stoneflies. I hate to admit it, but he was right.”

Stoneflies are far from the only research subject on the Nyack floodplain. Bob Hall, a stream ecologist and professor at the biological station, has landed funding to study how nitrogen is processed in the river and aquifer. Floodplains, he says, are complex systems that attract and hold not only tiny bugs, but all sorts of plant life and large animals, such as grizzly bears.

On a global scale, gravel-bed floodplains are threatened by a variety of forces, including dams, water diversion, agriculture, flood-control efforts, human development, transportation corridors, and climate change.

Hailey Jacobson closes up a primitive cabin used by volunteers as a kitchen and makeshift laboratory.

With all those threats, the untrammeled Nyack is critical to station scientists. Matson, a research specialist, makes monthly trips to the monitoring wells, where he maintains and calibrates equipment and records the fundamental factors that provide a long-term record of environmental conditions. Such a record is the bedrock of much scientific research.

On this crisp morning, the first stop for Matson is a monitoring well and a weather station in the middle of the hayfield just a few hundred yards from Highway 2. The first task involves measuring the barometric pressure at the site, information he will use to calibrate sensors at the wells.

Using a laptop computer and other devices, Matson removes the cap from the well and pulls on thin cables, eventually bringing a black tube — a dissolved oxygen monitor — to the surface. In this process, he points out a pale, pinkish larva of a stonefly that has been pulled from the depths.

This process will be repeated at other wells on the floodplain, some in the streambank areas scoured periodically by flooding, others in stands of dense, old-growth forest. Some of the sensors rest in the Middle Fork itself or in nearby creeks. Simply put, the monitors “give you clues to the biological activity that’s going on down there,” Matson says.

Matson has been doing monthly Nyack trips since 2013. In the winter, his equipment list includes skis and snowshoes to navigate deep snow and waders for crossing unfrozen creeks. In the summer, he adds bear spray to his gear.

He admits the work can turn tedious, especially in the depth of winter. But then the guy who grew up on the South Side of Chicago and was lured west as a college student recalls the sightings of elk, bears and wolf tracks near one of the wells. And there is the value of the scientific study in this remarkable Montana setting.

“I’ve probably been up here 100 times,” he figures. “That’s kind of neat to say.”

MAIN PHOTO: Phil Matson, a research specialist with the Flathead Lake Biological Station, winterizes a precipitation monitor at the weather station at Nyack Flats.