Field investigation and hydrological modelling of a sub-arctic wetland system by SLURP and WATFLOOD

• Main Author: Jing, Liang
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2009
• Subjects: Arctic; Hudson Bay; Hudson; Churchill; Climate change; Subarctic
• Online Access: https://research.library.mun.ca/9163/; https://research.library.mun.ca/9163/1/Jing_Liang.pdf

The wetlands existing as bogs, fens, swamps, marshes and shallow water comprise 14% of Canadian land. Recently, there are growing research interests in the hydrological characteristics of arctic and subarctic wetland systems in the need for more efficiently conserve wetlands and assess climate change related impacts. This research targeted the Deer River watershed near Churchill, Manitoba, which presents a typical subarctic wetland system in the Hudson Bay Lowlands. An extensive field investigation was first conducted from 2006 to 2008 to facilitate in-depth understanding of the wetland hydrology; and two semi-distributed hydrological models, SLURP and WATFLOOD, were employed to simulate the hydrologic cycle in the targeted subarctic wetland. -- The 28-year historic data (1978 - 2005) revealed a steady elevation of mean temperature and accumulative precipitation in the summertime (late June - early October). The 3-year field observation (2006-2008) also provided evidence to indicate a warming climate in the watershed. Frost table, soil moisture and streamflow were monitored and analyzed to advance the acknowledgement of the climatic, geographical and hydrological characteristics of the subarctic wetlands. The frost tables at the monitored transects were declining and reciprocal at their distances to the stream channels because of the subsurface flow within organic layer moving towards the stream and accelerating the thaw of frozen soil. Following the major recharge period during the snowmelt, soil moisture contents in the shallow layers of the wetland kept declining over time throughout the summer. The water discharges were low before September due to low precipitation and strong evapotranspiration as well as expansion of storage capacity of the organic soil layers, and then gradually increased due to the intensive precipitation in the fall. All the monitored streams showed prolonged responses to precipitation due to the combined effects of shallow impermeable frost table, porous soil, and varied soil storage ...