The dispersed deluge: Freshwater flow from glaciers and coastal rainforests to the Gulf of Alaska
| Authors: | Andrea Watts, Frances Biles, David V. D'Amore, Richard T. Edwards |
| Year: | 2023 |
| Type: | Science Findings |
| Station: | Pacific Northwest Research Station |
| Source: | Science Findings 257. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 6p. |
Abstract
The coastal zone of southeast Alaska contains thousands of rivers that drain into the Gulf of Alaska. This is the wettest and most topographically varied region in North America. The deluge of freshwater plays a critical role in supporting the Gulf of Alaska’s terrestrial and aquatic ecosystems as well as regional economies. However, the amount, timing, location, and source of freshwater flows into the ocean throughout the year are not well understood.
Two teams of researchers from the USDA Forest Service Pacific Northwest Research Station; U.S. Geological Survey; University of Alaska; and British Columbia Ministry of Forests, Lands and Natural Resource Operations took complementary approaches to learn more. They analyzed measured streamflow from gaged streams statewide and created a model to estimate freshwater flow across the drainage basin. The analysis of statewide streamflows revealed that rainfall, snowmelt, and high-elevation snow and ice storage create streamflow patterns that affect the timing and volume of freshwater flowing through a watershed. At the regional scale, the southeast Alaska drainage basin has a mean annual freshwater discharge of 430 km3, and watershed discharge is affected by its size and streamflow drivers.
Collectively, this information can help managers identify watersheds where streamflow drivers may be vulnerable to climate change and anticipate changes to stream discharge that might affect aquatic resources or infrastructure such as bridges and culverts.