CGRG Bibliography of Canadian Geomorphology
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Author : Bobba, A.G.; and Prowse, T.
Date : 2002.
Title : Hydrological effects of hypothetical climate change in the arctic watershed, Coppermine River, NWT, Canada.
Publication : American Institute of Hydrology. 2002 Annual Fall Conference, October 13-17, Portland, Oregon.
Issue :
Page(s) :
Abstract
The hydrological sensitivities to long-term climate change of a Coppermine River watershed in the Arctic were analyzed using a watershed runoff model. The model is described by an interdependent tank-cascade of reservoirs using mass balance coupled with linear reservoir concepts. The model is physically based and uses climatological considerations. To perform the sensitivity analyses; hypothetical climate changes were used to alter a current time series of temperature and precipitation. The altered time series were then used as inputs to a calibrated model that translates these inputs into estimates of runoff. Mean annual and seasonal runoff resulting from a range of hypothetical climate changes were compared and evaluated. Snowmelt and net-supply computations are separable from the mass balance determinations and are based on a simple heat balance. Partial area concepts are used to determine recharge and surface runoff. Losses are determined from joint considerations of available energy for actual and potential evapotranspiration, and of available moisture in the soil horizons by using climatological concepts, relevant for large data-poor forested areas. Water balance modeling techniques, modified for assessing climate effects, were developed and tested for the watershed using climate change scenarios from both state-of-the-art general circulation models and a series of hypothetical scenarios. The interaction between surface and subsurface water is discussed in relation to climate change. Results indicated that in general, changes in precipitation had a larger effect on changes in runoff than did changes in temperature. Changes in precipitation had significant effects on runoff during all seasons. Changes in temperature primarily affected the temporal distribution of runoff through the year. Changes in temperature affected the timing of snowmelt and the ratio of rain to snow, and therefore the effects of temperature were particularly significant during the spring and summer seasons. On an annual basis, increases in temperature led only to slight decreases in runoff. Results also indicated that the effects of an increase in mean annual temperature of 1oC on annual runoff could be offset by an increase in annual precipitation of 10 %, and that the magnitude of natural climatic variability was large and might mask the effects of long-term climate changes. These hydrological results raise the possibility of major environmental and socioeconomic difficulties, and have significant implications for future water resource planning and management.
Bibliography of Canadian Geomorphology