Document Type

Thesis

Degree Name

Master of Science (MSc)

Department

Geography & Environmental Studies

Faculty/School

Faculty of Arts

First Advisor

Dr. Brent B. Wolfe

Advisor Role

Graduate Coordinator

Second Advisor

Dr. Roland Hall

Advisor Role

Professor

Abstract

Northern lake-rich landscapes are vulnerable to increases in surface air temperatures and are changing in dynamic ways. Current meteorological records indicate that some of the greatest warming in the past century has occurred in the Hudson Bay Lowlands (HBL). As the HBL is an extensive wetland consisting of hundreds of thousands of shallow lakes and ponds, it is difficult to anticipate the long-term implications that climate change will have on pond water balance. To develop and implement long-term monitoring of hydrological conditions, sampling of pond water isotope composition has occurred during the past six years in Wapusk National Park (WNP), located in the HBL. This research is part of a collaboration among WNP, Wilfrid Laurier University and the University of Waterloo and is designed to establish standard operating procedures that will be incorporated into hydrological monitoring protocols for sampling ponds within the Park.

Previous studies have implemented long-term hydrological monitoring programs in thermokarst landscapes using water isotope tracers. Water isotope tracers are an excellent tool for characterizing spatial and temporal variability of pond water balances. Here, we use water isotope tracers (18O and 2H) on 16 ponds in WNP, northern Manitoba, employed over a six-year sampling period. Water isotope samples were collected three times each year during 2010 – 2015 (early, mid- and late ice-free season) to evaluate seasonal and annual patterns of pond water balance, and their drivers. An isotope framework based on evaporation pan data was developed to provide reliable and accurate means for interpreting water isotope compositions. A coupled-isotope tracer method was applied to obtain estimates of the isotope composition of input water (dI) and evaporation to inflow (E/I) ratios. Results provide insight into meteorological and catchment conditions influencing the seasonal, annual and spatial variability in pond water balance. Generally, dI values indicate pond water balances during the monitoring interval are influenced mainly by rainfall. E/I ratios reveal that ponds in the coastal fen and peat plateau ecozone are more influenced by mid-season evaporation and are more susceptible to pond-level drawdown than those in the boreal spruce ecozone. Higher than climate normal precipitation during 2014 and 2015 offset mid-ice-free season evaporation in most ponds. These results indicate that pond hydrological responses to climate change are likely to be complex and are related to catchment characteristics and ice-on and ice-free precipitation amounts. Data from the water isotope framework will be shared with Parks Canada as a tool for future monitoring. Ongoing monitoring will provide key hydrological metrics for current pond water balance conditions to monitor future responses to climate change.

Convocation Year

2017

Convocation Season

Fall

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