Tapped lakes as sediment traps in an Arctic delta

• Published in: Proceedings of the International Association of Hydrological Sciences
• Main Authors: J. Walker, M. McGraw
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2015
• Subjects: Environmental sciences; GE1-350; Geology; QE1-996.5; Arctic; Ice; permafrost; wedge*; Alaska
• Online Access: https://doi.org/10.5194/piahs-367-407-2015; https://doaj.org/article/d0f47aa64df5419ea49aa4115e808196

Lakes within the Colville River delta in northern Alaska, USA, vary in size from small ponds created by ice-wedge growth to thaw lakes that are as much as three kilometres long and ten metres deep. As the river migrates, lake edges are breached and the lakes are drained. Such lake tapping is aided by permafrost thaw and ice wedge melt and, in the case of the larger lakes, by wave action within them. Once a lake is tapped, it drains rapidly creating a deep scour hole at its entrance and from then on it is subject to the varying stages and discharge of the river. During flooding, when the river is transporting its largest amount of sediment, the tapped lakes become settling basins and rapidly fill. The Colville River delta has lakes in all stages from freshly breached to those that are now being destroyed by channel migration.