Effects of thermo-erosion gullying on hydrologic flow networks, discharge and soil loss

• Published in: Environmental Research Letters
• Main Authors: Etienne Godin, Daniel Fortier, Stéphanie Coulombe
• Format: Article in Journal/Newspaper
• Language: English
• Published: IOP Publishing 2014
• Subjects: permafrost; hydrologic connectivity; arctic hydrology; ice-wedges; gullies; wetland; Environmental technology. Sanitary engineering; TD1-1066; Environmental sciences; GE1-350; Science; Q; Physics; QC1-999; Arctic; Bylot Island; Canada; Nunavut; The Gully; glacier*; Ice; wedge*
• Online Access: https://doi.org/10.1088/1748-9326/9/10/105010; https://doaj.org/article/b63eaaa74203494da4fc5657f41fa4e3

Thermo-erosion gullies in continuous permafrost regions where ice-wedge polygons are widespread contribute and change the drainage of periglacial landscapes. Gullying processes are causing long-term impacts to the Arctic landscape such as drainage network restructuring, permafrost erosion, sediment transport. Between 2009 and 2013, 35 gullies were mapped in a polygon terrace in the valley of the Glacier C-79 on Bylot Island, Nunavut (Canada), one of which was monitored for its hydrology. A gully (R08p) initiated in 1999 in a low-center polygon terrace. Between 1999 and 2013, 202 polygons over a surface of 28 891 m ^2 were breached by gullying. Overall, 1401 polygons were similarly breached on the terrace in the valley before 2013. R08p is fed by a 1.74 km ^2 watershed and the hydrological regime is characterized by peak flows of 0.69 m ^3 s ^−1 and a cumulative volume of 229 662 m ^3 for 2013. Historic aerial photography from 1972 and recent field surveys showed a change in the paths of water tracks and an increase in channelized flow in the gully area from none to 35% of the overall flow path of the section. The overall eroded area for the studied gullies in the valley up to 2013 was estimated at 158 000 m ^2 and a potential volume close to 200 000 m ^3 . Gullying processes increased drainage of wetlands and the hydrological connectivity in the valley, while lowering residence time of water near gullied areas.