The glaciers that provide stream flow and cool temperatures for some of the region’s most threatened salmon are disappearing.
“This is probably the largest decline in glacier area and volume recorded in the North Cascades over the last 30 years,” said Oliver Grah, water resources program manager for the Nooksack Indian Tribe.
Glacier-fed rivers, such as the Nooksack, depend on enough glacier melt to produce sufficient stream flows and cool temperatures for salmon to spawn. Researchers are concerned that, due to climate change, the low- and mid-elevation glaciers on Mount Baker will be gone by the turn of the century.
“Probably glaciers at higher altitudes will persist, but there won’t be enough glacier mass up there to produce enough melt to sustain the stream flows and cool stream temperatures we have now in late summer,” Grah said.
Already the Nooksack River is impaired by high temperatures and sediment, leading to a decrease in salmon productivity. The river is recognized as “water quality impaired” under the federal and state clean water acts.
“Healthy salmon stocks are vitally important to the Nooksack Indian Tribe; it’s ingrained into our identity, our culture,” said Gary MacWilliams, the tribe’s natural resources director.
For the past four years, tribal natural resources staff has been working with glaciologist Mauri Pelto to measure Mount Baker’s glaciers to determine the rate of accumulation compared to melt, or ablation.
“Most of the glaciers on Mount Baker are receding,” Grah said. “The line between snow accumulation and glacier ablation is moving higher in elevation. Glacier area and mass are declining.”
Preliminary results suggest that valley glaciers on Mount Baker have receded more than 1,000 feet in the last 30 years. The Mazama Glacier in the upper Nooksack River watershed has receded almost 2,000 feet. Low- to mid-elevation glaciers have receded on the order of 700 feet during this time.
With last summer’s record high temperatures and drought, the research team saw drastic differences from previous years in exposed ice, retained snowpack, runoff and sediment loads from the glaciers.
“Most or all of this year’s snow accumulation on the low- to mid-elevation glaciers disappeared,” Grah said. “Little of previous years’ snow remained as well at the upper most elevation of the low to mid-elevation glaciers. Most of these glaciers had exposed ice over most of their areas by the end of September.”
The tribe has contracted the University of Washington and Western Washington University to model glacier behavior and the hydrology of the Nooksack River under different climate change scenarios. Preliminary results show that stream flow conditions experienced this year are very similar to the modeled flows.
“Assuming climate in the future is similar to environmental conditions this year, we have a good idea of what to expect in the future,” Grah said.
These conditions will further impede the Nooksack Indian Tribe’s ability to harvest sustainable populations of salmon for ceremonial, cultural, subsistence and commercial uses.
“We need to plan now for this changing climate to promote salmon survival and a resilient riverine ecosystem in the future to protect our treaty rights,” MacWilliams said.
For more information, contact: Oliver Grah, water resources manager, Nooksack Tribe, 592-5140 Ext. 3139 or [email protected]; Kari Neumeyer, information officer, NWIFC, 360-528-4406 or [email protected].