Current and Recent Research Projects
Climate Change Impacts on Water
Groundwater Response to Extreme Weather Events in Various Hydrogeological Regimes across Southern British Columbia (MSc, Nott, 2024). Across the Pacific Northwest, drought and precipitation extremes are becoming stronger and more frequent. Few studies have explored groundwater responses to extremes in mountainous regions. Here, well and catchment scale approaches are used to determine the responses across different hydroclimatological and hydrogeological contexts by: (1) analyzing groundwater levels in observation wells on the South Coast of British Columbia (BC), and (2) analyzing catchment responses in three integrated hydrological models. Across the South Coast, two distinct styles of groundwater responses are identified, as a function of hydraulic connectivity to the Fraser River, with aquifers hydraulically connected to the Fraser River likely being more drought resilient during summer due to the influence of the river’s freshet. Model results show that catchment aquifers are sensitive to extreme events; greater consecutive dry days deplete aquifers while atmospheric rivers provide substantial recharge. Catchment boundary conditions and hydrogeological characteristics ultimately determine aquifer response to extremes.
Characterizing Atmospheric Rivers and the Effects of Extreme Precipitation on Nitrate in Agricultural Settings (MSc, Greenblat, 2024). This study characterized the isotopic composition of extreme precipitation and surface waters and explored the relation between extreme precipitation and nitrate in southwest British Columbia. Atmospheric river (AR)-derived precipitation was isotopically depleted compared to non-ARs, but not distinct enough to be manifested in surface waters. The d-excess values of precipitation and surface waters varied seasonally and suggest that winter precipitation from high elevation contributes to summer surface waters. In the North Alouette Watershed (NA), surface water nitrate concentrations are low (~1.0 mg/L) and vary minimally after extreme precipitation events. In the Abbotsford Sumas Aquifer (ASA), nitrate in groundwater is elevated (~3.6 mg/L), but no relationship with extreme precipitation events was observed. At both locations, the sampling frequency was likely too low. However, numerical modelling of nitrate transport during extreme events suggests rapid mobilization in the ASA, while in the NA, nitrate remains stored in the vadose zone.
Aquifer-Stream Hydraulic Connectivity
Groundwater - Surface Water Exchange Dynamics in Low- Gradient and Tidally Influenced Streams in the Lower Fraser Valley (PhD, Mitton, in progress) The study aims to build an understanding of groundwater-surface water exchanges in tidally influenced and low-gradient stream systems, and how hydrogeological and hydrological processes interact to drive hydrological variability. A main goal is to link aquifer and stream dynamics mechanistically to environmental response metrics (e.g., hydraulic-habitat, geochemical, and biological variables) to support management decisions related to the evaluation of potential impacts of hydrological alteration (e.g., groundwater pumping) and the determination of environmental flow needs (EFNs) in groundwater dependent, low- gradient, and tidally influenced streams.
Investigating Temperature Dynamics and Evaluating Thermal Infrared (TIR) Remote Sensing in the North Alouette River, British Columbia (MSc, Antesz, 2024). This study compared drone- and satellite-based thermal infrared (TIR) methods for measuring stream temperature, and used in-situ streambed temperatures and stable isotopes to characterize the thermal and hydrologic regimes of the North Alouette River in southwestern British Columbia. The drone-derived temperatures closely matched in-situ measurements during low-flow conditions and when the sun was not directly overhead. The spatial unmixing technique applied to Landsat data accurately represented the temperatures of the stream under low atmospheric moisture conditions. The thermal and hydrologic regimes of the river are closely linked. Streambed temperatures varied seasonally with stream stage, but downstream locations warmed more than upstream during the summer. The isotopic composition of the river water became gradually enriched from May through the summer, peaking in September and October, before shifting back to more depleted signatures in November, reflecting the seasonal variation in contributions from the headwaters and likely groundwater in the valley bottom.
Risk to Water Quality and Quantity
A Forensic Analysis of Groundwater Depletion in British Columbia (MSc, Shotayo, 2026). Groundwater depletion is a global problem that results in declining groundwater levels and potential impacts to streamflow. This study focuses on the evolution of groundwater depletion in British Columbia. First, a forensic analysis of groundwater depletion is conducted in several small aquifers that have experienced declining trends in groundwater levels in an attempt to identify change points and their causes. Second, the evolution of a small watershed, Bertrand Creek Watershed in the Fraser Valley, is simulated from 1937 to present day to quantify the effect of pumping on the water balance.
An Exploration of Groundwater Recession Rates in British Columbia Aquifers (MSc, Ludwig, in progress). Groundwater recession is a natural process whereby groundwater levels decline when recharge rates are exceeded by aquifer drainage rates. In British Columbia, the end of the recession period typically occurs in late summer when the fall rains begin. However, in recent years, the recession period has lengthened due to persistent summer drought conditions. This study explores the range of recession rates across BC using provincial observation well data. Numerical models are run to explore the impact of pumping individual wells as well as the cumulative effects of pumping on recession rates.
A Morphological Approach to Evaluating Risk to Freshwater Resources in Coastal Deltas (PhD, Anderson, 2023). Coastal deltas house more than 335 million people worldwide in some of the largest population centers in the world, including growing megacities such as Shanghai, Dhaka, and Bangkok. These populations often rely heavily upon groundwater resources to meet domestic, agricultural, and industrial water demands—making the sustainability of fresh groundwater resources critical to ensuring the longevity of coastal communities. This research uses morphodynamic modeling to simulate the formation of coastal deltas and explore how delta morphology impacts hydrogeologic characteristics within deltas. Data from deltas around the world are used to create 207 unique models that span the full range and combination of fluvial and marine influences. Simulated landforms depict the characteristics expected in fluvial, wave, and tidal influenced deltas; these landforms are used to generate spatially varying permeability profiles for each simulated delta. A distance-based sensitivity analysis shows that deltaic permeability, hydraulic gradient, and groundwater flow rates are sensitive to changes in delta morphology and geomorphic characteristics. Two-dimensional density-dependent groundwater flow and solute transport modeling is used to simulate the horizontal fresh-saline water distribution within the shallow subsurface in representative fluvial, wave, and tidal deltas. The volume of saline water in the shallow subsurface within deltas is estimated to vary between 36% and 89% of the total groundwater volume, depending on the morphodynamic influences and the amount of recharge the delta receives. Results show that deltas located in dry climates are most susceptible to salinity and that wave or fluvial delta are especially susceptible. The generic groundwater models of the three delta types are used to understand the vulnerability of 55 real deltas to groundwater salinization through lateral saltwater intrusion. The result of this research provides an initial estimate of the amount of freshwater within deltas, identifies where salinity is most likely to occur within a delta, and suggests which delta types are most vulnerable to groundwater degradation.
An Integrated and Data-driven Modeling Approach to Reconstruct Tsunami Inundation and Groundwater Salinization (MSc, Bartlett, 2025). An important consequence of tsunami inundation on a coastline is the salinization of aquifers. Tsunami-related salinization may yield groundwater unusable for several years. Key variables of uncertainty related to the effects of tsunamis on groundwater include tsunami inundation extent and flow depth. Thus, this problem requires methodologies from both the paleoseismological and hydrogeological disciplines. This study applies inverse and forward tsunami modeling techniques to better constrain inundation relating to the 1964 Alaska tsunami at Port Alberni, British Columbia, Canada. A combination of these methods suggests inverse tsunami modeling, which can be applied to older events in the sedimentary record, underestimates inundation depth compared to forward modeling. The first geologically constrained tsunami inundation map at Port Alberni is generated, and these results are used as input parameters for unsaturated and saturated zone hydrogeological modeling. This modeling suggests that groundwater resources in Port Alberni should be monitored for a minimum of two years following inundation.
Groundwater Drought: Developing Quantitative Indicators and Mapping Drought Susceptible Aquifer - Stream Systems in British Columbia (MSc, Gullacher, 2022). Aquifers in mountainous regions can be susceptible to periods of drought, but the aquifer response to drought is complex due to groundwater – surface water interactions. In this study, early season and drought season core indicators of groundwater drought are derived from groundwater level, streamflow and climate data. The indicators are informed by the response mechanism of the aquifer-stream system, with two end-members: recharge-driven or streamflow-driven. Generalized additive models are used to determine which combinations of predictor variables for specific regions in British Columbia are associated with summer groundwater levels. Additionally, the Standardized Groundwater Level Index is used to identify wells that had pronounced responses to drought. Drought susceptibility mapping of aquifers in the Okanagan Basin was completed using aquifer hydraulic diffusivity and well density. The classification identified five aquifers that are highly susceptible to drought. The combination of indicators and the aquifer drought susceptibility map can be used for drought-related decision-making in British Columbia.
Hydrogeochemistry
Investigation of the Speciation of Arsenic and Selenium in Pyrites and Implications for Element Mobilization During Oxidation of Arsenic- and Selenium-Bearing Pyrites (PhD, J. Ross-Lindeman, 2024). Arsenic and selenium can be harmful to human, animal, and plant health so it is important to understand how these elements accumulate in the environment. A process known to release these elements is the oxidation of pyrites with substituted arsenic and/or selenium. Previous studies on arsenic and selenium focused on their mobility once released, however, there has been less research on their mobilization during pyrite oxidation. This study examines arsenic and selenium mobilization from pyrite oxidation. Samples containing pyrites with arsenic and/or selenium were characterized through geochemical and mineralogical (XRD, SEM, synchrotron XANES and micro-XRF) analyses. Laboratory-scale oxidation experiments were conducted on the pyritic samples to determine arsenic and selenium mobilization rates from pyrite oxidation. Reaction path models were also run to better understand the processes in the experiments. The characterization study corroborates previous findings that arsenic and selenium occur in the -1 oxidation state substituting for sulfur in pyrite. Furthermore, it demonstrates that XANES of arsenic- and selenium-pyrites have intrinsic features which differentiate the arsenic or selenium substituting for sulfur from oxidized arsenic and selenium species. The oxidation study finds that arsenic is initially mobilized at a faster rate than sulfate when pyrite is oxidized. Arsenic mobilization rates appear to slow over time, but this decrease in rate may be because arsenic is depleted at the pyrite surface. Selenium may be mobilized at a similar rate to sulfate but findings from this study are inconclusive and further work is needed for confirmation. The modeling study shows that model results for arsenic mobilization from oxidation of arsenic-pyrite are clearly different than experimental results. Model results for selenium are inconclusive because of the limited experimental results. The difference between model and experimental results for arsenic are because the models do not account for faster arsenic mobilization rates relative to sulfate. More experimental data on arsenic- and selenium-pyrite oxidation is clearly required to develop more comprehensive models. Moreover, more experimental data on arsenic and selenium mobilization rates during pyrite oxidation will facilitate the development of procedures for long-term monitoring and remediation.
