http://hdl.handle.net/10388/12188

Streich, S. (2019). The hydrological functions of a mountain valley-bottom peatland under drought conditions http://hdl.handle.net/10388/12188

Mountain wetlands act as a sponge, storing water during wet periods and releasing water during dry periods. They are of particular interest as they have been shown to help mitigate downstream hydrological events, such as droughts and floods. Previous studies in northern wetlands have indicated the timing and magnitude of wetland runoff is inconsistent, with atmospheric and environmental conditions playing a key role in the production of wetland runoff. However, little work has been done to study the factors that influence flow between wetlands and streams systems in mountain valley-bottom regions. During the spring and summer of 2017, runoff dynamics of the Sibbald Research Wetland, a peatland in the Canadian Rocky Mountains, were analysed using a water balance approach and application of the Spence (2007) hydrological functions model. This model states that a peatland can store, transmit or contribute water to its outlet. An additional hydrological function, evapotranspiration, was added to this model to account for storage loss. Results show that the peatland was able to maintain outlet baseflow throughout the study period, despite a severe regional drought. Furthermore, the peatland transmitted water to its outlet when abundant ground frost was found in the upper 50 cm peat, whilst contributing water during the frost-free period. Additionally, large precipitation events initiated flows into peat storage which were quickly followed by runoff generation to the stream. Evapotranspiration occurred daily and accounted for the largest loss of storage from the system. This research indicates the importance of mountain peatlands in regulating streamflow during severe drought and during high precipitation events, as well at the importance of frozen ground and precipitation in determining the hydrological functioning of mountain peatlands. Moreover, this research underlines the need for further study in mountain peatlands across elevation gradients and for a variety of climatological and meteorological conditions as these controls on hydrological function may differ between peatland biophysical states and with atmospheric conditions.

Masters, University of Saskatchewan, Mountain Water Futures

http://hdl.handle.net/10388/12188