CGRG Bibliography of Canadian Geomorphology
Search Results
Author : Beltaos, S.; and Prowse, T.
Date : 2001.
Title : Climate impacts on ice-jam flooding of the Peace-Athabasca Delta.
Publication : Annual Scientific Meeting of the Canadian Geophysical Union. May 14-17, 2001, University of Ottawa, Ottawa.
Issue :
Page(s) :
Abstract
The Peace-Athabasca Delta (PAD) in northern Alberta is one of the world’s largest and biologically productive freshwater deltas. Previous work has shown that the combined effects of flow regulation after 1971, and climatic variations have inhibited the formation of ice jams that cause flooding of the delta, and especially of the perched basins, leading to considerable reduction in habitat. The issue of climate change, whose impact on the hydroclimatic regime of the delta is likely to be significant, underscores such concerns. The hydraulic and climatic conditions that produce major ice jams on the lower Peace, and thence flooding, have been delineated via numerical modelling and analysis of local breakup processes. They include: (a) spring flows > 4000 m 3 /s at the Peace Point hydrometric station; and (b) sufficiently rapid runoff to ensure that the ice does not decay significantly prior to breakup. Consequently, ice-jam flood events can be predicted if daily flow hydrographs and climatic inputs are given. This type of information can be generated by hydrological modelling, using GCM or RCM outputs. Though preferable, this approach must await the implementation and calibration of an appropriate hydrological model for the Peace River basin. A less quantitative, more empirical, approach is to use surrogate indices for ice jamming potential based on past climatic records. These can then be examined for future climatic scenarios using daily temperature and precipitation output of GCMs (or RCMs). Two indices that appear to predict past ice-jam events are accumulated snow precipitation over the winter months, and rate of accumulation of degree-days of thaw during early spring. Daily GCM output has been examined for current and future conditions (2070-2099). This paper examines the predicted altered frequency of ice jamming and the implications for the ecosystem health of the PAD.
Bibliography of Canadian Geomorphology