Permafrost hydrogeology

点击翻译按钮获取中文摘要

Increasing temperatures in the Arctic over the past decades has been accompanied by an increase in sub-permafrost and intra-permafrost groundwater discharge to rivers. Hydrometric data from permafrost drainage basins show strong interannual variability in baseflow discharge, although with a long term trend towards increased groundwater discharge. This increased flow can affect seasonal discharge in rivers, the timing and severity of the spring freshet and may also exacerbate the impact of seasonal icing (aufeis) formation on communities and infrastructure. This program will take full advantage of Canada's only accelerator mass spectrometer facility that we recently established at the University of Ottawa, with capabilities for very low level and compound-specific radiocarbon plus associated facilities for noble gas isotopes analysis. The objective of this research program over the next five years is to determine the mechanisms of groundwater recharge and quantify circulation through permafrost watersheds, the impacts of climate variability, and how contaminants are transported through components of these flow systems. Spectral analysis of discharge data shows strong correlations with climate phenomena observed for the western Canadian Arctic, including the solar cycles and El Nio. This collaborative research will integrate spectral and statistical analysis of historical hydrological and climatological data sets with field investigations and laboratory analysis of stable and radioisotopes and noble gases , to build a comprehensive model of the seasonal timing, mechanisms and climate controls on groundwater circulation. Collaboration with northern groups (Yukon College, Gwitch'in Land and Water Board; Yukon Water Survey, Environment Yukon) will continue to provide access, field guides through backcountry terrain, sampling assistance for project HQP and northern knowledge. Sampling to characterize groundwater baseflow during the pre-freshet period and the spring freshet through to freeze-up. Analysis includes isotopes and the carbon system (13C and 14C, DIC, CH4, DOC, acetate and other fractions). This program will contribute new research at contaminated sites to help calculate rates of biodegradation of contaminants in soils. We will measure rates of biodegradation and organic contaminant migration in development-impacted watersheds. HQP in this work gain extensive northern research experience and are exposed to the latest analytical methods in our new Advanced Research Complex (ARC) including radiocarbon by AMS and noble gases. This research program is one of very few considering the groundwater component of permafrost hydrology, and the fate of organic contaminants in these systems. This is of particular relevance to a region experiencing accelerated development at a time of shifting climate regimes.