This story is Part I of a two-part series on the Tanana River Watershed. See Part II here.
What do a St. Patty’s Day party and a sub-Arctic river have in common? An abundance of green dye, which acts as a festive element for the first and a scientific tool for the second.
A group of Alaskan scientists used this green dye as a tracer in studying the intersection of glaciology and hydrology in subarctic rivers, and recently published their findings in Geophysical Research Letters. They found that glacial meltwater interacts with rivers and groundwater across the landscape in complex ways, which has implications for the life the landscape supports—including humans.
I spoke with the study’s lead scientist, Anna Lilijedahl, over Skype at opposite ends of our days. Anna, who was attending a conference in Oxford, sat on her hotel room bed in a sweatshirt that read “Yukon River Camp,” and I huddled in a sweater at my desk in Fairbanks, Alaska, listening as she talked to me about the sub-arctic Interior Alaska landscape I grew up in.
Small rivers are difficult to sample in winter, she told me, because of the thickness of the ice build-up. “Little channels of water run through it like a spider web, you can hear it in the ice if you listen,” she said.
From listening to wintertime trickles to trekking across glaciers, Lilijedahl and her team have engaged intensely with the Tanana River watershed, a major tributary of the Yukon River. Internationally important to subsistence lifestyles, remote northern travel, and commercial salmon fisheries, the river flows over 2,000 miles through Alaska and Canada before draining into the Bering Sea.
Lilijedahl’s study involved extensive surveys on Jarvis Glacier, snow machine travel in the mountains, and probing frozen rivers to gauge their flow. What I noticed the most about Lilijedahl during our conversation was how she uses hydrology to bring people closer to their landscape, and to one another.
“We’re really excited about her work because it has a big impact not only on our community, but also for the agency,” said Jeff Durham, program director of Salcha-Delta Soil and Water Conservation District, a state agency that works with local landowners and government agencies to manage natural resources in nearly four million acres of Interior Alaska. The project constituted a collaboration between the University of Alaska Fairbanks, where Lilijedahl is based, the Salcha-Delta Soil and Water Conservation District, which provided logistical and backcountry support, and researchers from both the U.S. Geological Survey and a research branch of the U.S. Army.
According to Durham, this collaboration has drawn both attention and funding to the project. One proposal reviewer from the National Science Foundation wrote a letter naming this partnership as a hallmark of the scientific process, emphasizing that scientists should work with local agencies, not just live in the halls of academia. “It’s a great opportunity for us to jump in with her and get a lot of information. We can look forward toward what will happen with the water table and our community,” Durham said.
As he drove through Interior Alaska, Durham talked to me by phone about what he calls the “boom and bust town” of Delta Junction, a small community near Jarvis Creek where you can leave a chainsaw in the back of your truck at the grocery store and it won’t be stolen. As Jarvis Glacier continues to melt, and eventually disappear, Delta Junction’s aquifer may dry up. When this happens, wells, which are a major resource in an area without municipal water, will run dry. According to Lilijedahl, the watershed’s glaciers are so diminished that the amount of water in aquifer storage is already decreasing.
Lilijedahl gave a presentation about her research findings in Delta Junction, surprising its residents with the importance of far-away Jarvis Glacier to the aquifer. Lack of understanding about the connection between mountain glaciers and lowland water resources is common, says Lilijedahl. Her paper in Geophysical Research Letters concludes that “high-latitude mountain glaciers represent an overlooked source to subarctic river discharge and aquifer recharge.” She calls the Jarvis Creek watershed a “proxy watershed” and believes the relationship between glacial melt and aquifer recharge exposed by her research will hold true for other subarctic regions in Alaska, Canada, and beyond.
“The fact that she’s worked so closely with a local natural resource agency, shared information, made an effort to come into the community—that’s the key in what Anna’s doing,” said Durham. “She brings complicated information into our community and makes it palatable. It’s easy to have those conversations in the halls of academia. Having them with someone who doesn’t have the background is the real challenge.”
With regards to Jarvis Glacier and Delta Junction’s water resources, the future is coming. When will the water levels drop? In Durham’s lifetime or his children’s? As water pours from Jarvis Glacier into the aquifer, it melts the permafrost and carves the aquifer deeper, increasing water storage capacity and releasing carbon stored in the permafrost. This process raises a host of future research questions for Lilijedahl. “How much permafrost have we really thawed because of this increase in glacial melt?” she wonders. “This melt brings old carbon stored for thousands and thousands of years into the river, and in contact with bacteria.” Typically, attention is focused on glacial melt’s contribution to sea level rise, she says, but there are several directions in which to explore the impact on the terrestrial ecosystem.
Alaska is ground zero for climate change, according to Durham. “It’s obvious that the Jarvis is drying, we can see that from a visual standpoint. It’s a canary in a coal mine, and that’s why this work is so important,” he said. He expects the state to see impacts from temperature rise before other places. “How will we build, and how will we deal with what has been built?” he wonders.
Melting permafrost has impacts all over Alaska, Durham says. Roads undulate, the ground becomes unstable, and the ultimate consequences for towns and infrastructure are still unknown. One consequence for Delta Junction’s infrastructure may actually be positive: stable through the year, Jarvis Creek discharge has a temperature of 6°C, the signature temperature of aquifer water in the watershed. Though it sounds chilly, this is actually warm, especially relative to winter temperatures in the region. Lilijedahl thinks that people in Delta Junction could use the water as heat source to warm their homes.
With major changes to life imminent in Delta Junction and other places in Alaska, partnerships between scientists and local agencies will lead the way in research and future mitigation efforts. As the landscape changes, the only choice is to draw closer to it, and to one another.