CGRG Bibliography of Canadian Geomorphology
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Author : Brock, B.; Wolfe, B.; and Edwards, T.
Date : 2008.
Title : Multi-year landscape-scale assessment of hydrological conditions in the Slave River Delta, NWT, using water isotope tracers.
Publication : Water, Weather, and Climate: Science Informing Decisions. Canadian Meteorological and Oceanographic Society 2008 Congress. May 25-29, 2008, Kelowna, British Columbia.
Issue :
Page(s) :
Abstract
Located on the south shore of Great Slave Lake, NWT, the hydrology of the Slave River Delta (SRD) is affected by a complex interplay of factors, including the flow regime of the Slave River and climate. Recent concerns about the impacts of upstream water use, declining river discharge and the effects of climate variability on the hydroecology of the SRD have prompted the need to further understand the crucial role of water in the ecosystem. Measurement of stable isotope (18O, 2H) and suspended sediment data from water samples collected from SRD lakes over three consecutive thaw seasons (2003-2005) provides a unique opportunity to tease apart the roles of the Slave River and climate on SRD hydroecology. While climate conditions were remarkably similar during the study period, the spring break-up period varied significantly, with moderate spring flooding in 2003, an absence of flooding in 2004, and a significant flood in 2005. Floodwater serves as a key hydrological input to lakes in the active delta, where the spatial extent of flooding is positively correlated with discharge on the Slave River. Later in the season, evaporation becomes one of the major factors controlling SRD lakewater balances. Using a coupled isotope tracer method, incorporating admixture of local and advected vapour, end-of-thaw-season lakewater balances are quantified. Results identify that water losses by evaporation exceed input for lakes in the relict delta. Interestingly, lakes in the active delta maintained positive water balances (input > evaporation) over the three year monitoring period, even in the absence of spring flooding (i.e., 2004). This information is critical when considering the implications of naturally- and anthropogenically-induced variations in climate and river discharge, consequent impacts on the hydroecology of the SRD, and resource management decisions for the delta and the nearby community of Fort Resolution.
Bibliography of Canadian Geomorphology