A Synthesis of Three Decades of Eco-Hydrological Research at Scotty Creek, NWT, Canada

Abstract

Abstract. Scotty Creek, Northwest Territories (NWT), Canada, has been the focus of eco-hydrological research for nearly 20 three decades. Over this period, field and modelling studies have generated new insights into the thermal and physical mechanisms governing the flux and storage of water in the wetland-dominated regions of discontinuous permafrost that characterizes much of the Canadian and circum-polar subarctic. Research at Scotty Creek has coincided with a period of unprecedented climate warming, permafrost thaw, and resulting land cover transformations including the expansion of wetland areas and loss of forests. This paper synthesizes field and modelling studies at Scotty Creek, and highlights the key 25 insights of these studies on the major water flux and storage processes operating within and between the major land cover types. This paper also provides insights into the rate and pattern of the permafrost thaw-induced land cover change, and how such changes will affect the hydrology and water resources of the study region.

Opposing Effects of Climate and Permafrost Thaw on CH4 and CO2 Emissions From Northern Lakes

“…Permafrost conditions strongly influence peatland hydrology and thus the hydrological connectivity of lakes to their surrounding landscape in this region (Quinton et al, 2019). Widespread permafrost precludes deeper groundwater flow but also blocks shallow flow paths and much peatland runoff enters hydrologically isolated depressions rather than connecting with lakes (Quinton et al, 2019;Vitt et al, 2000). Consequently, with less permafrost in warmer climates, there is increased connectivity of lakes with the surrounding peatlands, while lake position in the landscape determines the potential for regional groundwater recharge or discharge (Hokanson et al, 2019).…”

“…Permafrost expanded southward after the Holocene thermal maximum and reached its maximum extent following the Little Ice Age, ∼1,000 years ago (Pelletier et al, 2017). Permafrost conditions strongly influence peatland hydrology and thus the hydrological connectivity of lakes to their surrounding landscape in this region (Quinton et al, 2019). Widespread permafrost precludes deeper groundwater flow but also blocks shallow flow paths and much peatland runoff enters hydrologically isolated depressions rather than connecting with lakes (Quinton et al, 2019;Vitt et al, 2000).…”

A Semianalytical Interface Model of Soil Freeze/Thaw and Permafrost Evolution

“…The domain height is 3 m for all models and all scenarios, and a fixed temperature (−0.1°C) is imposed at the base of the soil profile. The surface temperature was based on two time series constructed from data collected at the Scotty Creek Research Station (SCRS, a field site located in discontinuous permafrost peatlands approximately 70 km south of Fort Simpson in the Northwest Territories; Quinton et al., 2019): the first, a representative of a stable peat plateau, and the second, a degrading permafrost body with a lateral talik. The water table was initially at a depth of 10 cm below the ground surface, and mass flux at the surface was applied seasonally, with an average ET rate (−1.728×10 −3 mm/day) applied in spring/summer and an average recharge rate (2.076×10 −3 mm/day) in the fall.…”

Mechanisms of Discontinuous Permafrost Thaw in Peatlands

“…The SC study basin was established in 1999, and is an ideal location for the study of permafrost degradation because it includes permafrost in different stages of degradation including stable permafrost, isolated and connected taliks, and permafrost‐free wetlands (R. Connon et al., 2018). The peat deposit in this study site ranges from 2 to 8 m in thickness, and overlays clay, silt/clay, and low‐permeability glacial till (Quinton et al., 2019). High permeability near‐surface peat soils drain readily when the water table is below the ground surface, leaving a relatively dry insulating surface peat layer that preserves permafrost underlying peat plateaux (Quinton et al., 2009).…”