Nov 7 2018

Uncharted Waters: Streamflow modeling project in Southeast Alaska kicks off with stakeholder meetings

a stream gauge attached to a bridge above the Herbert River

An effort to model the watersheds of southeast Alaska is coming to life as one of the AK CASC pilot projects.

Given the complex terrain, variable weather patterns, and extensive network of water systems in the region, a project of this magnitude and challenge has yet to be attempted. With the combined expertise of AK CASC senior scientists Uma Bhatt, Peter Bieniek, and new fellow Rick Lader, the team is taking strides forward.

With the USFS Tongass National Forest, Alaska Department of Natural Resources, National Weather Service, and the Alaska Department of Transportation, AK CASC scientists are working to determine the right questions to ask about freshwater flow dynamics in the region, and how to answer those questions together.

When it comes to collaboratively producing science, Bhatt sees benefits to both stakeholders and researchers. “Having a perspective on what you’re doing from someone outside your specialty immediately makes you look at [a project] differently. It enriches the way you interpret the data, and you see its value,” she says.

Early conversations highlighted some of the most needed model outputs for stakeholders, including estimates of total precipitation variability in coming years, rain and snowfall extremes, and less frequent occurrences like rain on snow events that make travel and transportation dangerous.

KK Prussian, a hydrologist working on culvert and infrastructure design for the US Forest Service, is one of the collaborators helping to shape the project. This group is bringing together climate modelers and those looking at streamflow and resource planning.

“That generally doesn’t happen. It’s hard, but it’s valuable,” Prussian says. “[The researchers] are trying to do something and deliver it in a way that’s useful by bringing stakeholders to the table.”

The resolution of most global climate models of future weather is too coarse to capture the highly varied terrain of southeast Alaska, and the regional-scale climate models necessary for this work have not been available in Alaska until recently.  But even a single grid block of a regional, or downscaled climate model can span 20-kilometers, rendering them little use in making local level planning decisions. Lader's work, with Bhatt and Bieniek, will create climate information with regional variability, including the effects of topography and coastlines, at a resolution that’s useful to planners, land managers, and decision makers.

Refining global climate models down to a 1-kilometer resolution requires supercomputing power and can take months at a time to generate. The data produced will help answer a range of questions, from providing information on small watersheds that like stream sampling stations, tracking sedimentation and landslide events, and looking at winter ice jam patterns, to tracking how changing freeze and thaw patterns affect forest health.

The resulting streamflow tool will also help decision-makers prepare for the rapidly changing climate of Southeast Alaska. Freshwater flow dynamics in Southeast Alaska are expected to dramatically shift over time with changes in precipitation and air temperature. Pinpointing the locations where high ecological value or risk and high rates of change overlap will be essential to stakeholders looking to prioritize infrastructure updates and restoration efforts.

To get involved with this project, contact principal investigator albidlack [at] alaska.edu (Allison Bidlack).