ABSTRACT: Identifying the roles of river regulation and variability of climate and river discharge on hydro-ecological dynamics of the Peace-Athabasca Delta: insights gained from a 1,500 year perspective.

CGRG Bibliography of Canadian Geomorphology
Search Results

Author :

Date :

Title :

Publication :

Issue :

Page(s) :

Abstract

We are using multiproxy paleolimnological analyses, coupled with dendroclimatic records, to assess the roles of river regulation for hydroelectric production on the Peace River and variability of climate and river discharge onhydroecological conditions of the Peace-Athabasca Delta, Canada. Landscape analyses of lake sediment records do not detect an effect of hydroelectric regulation, but provide unprecedented insight into this highly dynamic ecosystem. For example, results from an upland, perched basin provide evidence for 18th century drought that exceeds dryness experienced during the past few decades. Analyses of laminated sediments from an oxbow lake adjacent to a distributary of the Peace River similarly indicate an extended interval without major river-flooding during the 1700s. In contrast, evidence from several lowland ponds documents a multi-centennial high-water stand of Lake Athabasca at this time and throughout the Little Ice Age (LIA, ~AD 1600-1900). These reconstructions suggest snowmelt-dominated runoff in the eastern Rocky Mountains sustained greater summer discharge in the Peace and Athabasca rivers and higher levels in Lake Athabasca during the LIA, whereas an arid climate led to low water levels in the upland areas of the delta. Preliminary results also suggest that post-LIA hydroecological conditions, which reflect a shift to a rainfall-dominated runoff regime, may be analogous to conditions that prevailed during the Medieval Warm Period. These long-term perspectives are essential to inform ecosystem stewardship in light of continued reduction in glacial meltwater supply and warming.

Bibliography of Canadian Geomorphology