CGRG Bibliography of Canadian Geomorphology
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Author : Branfireun, B.A.; and Roulet, N.T.
Date : 2000.
Title : The influence of inter-annual climate variability on boreal catchment hydrology.
Publication : Annual Scientific Meeting, Canadian Geophysical Union, Banff, Alberta, May 23-27, 2000.
Issue : Abstract.
Page(s) :
Abstract
Current investigations of catchment-scale hydrological processes are based upon increasingly short-term, small-scale empirical studies. These types of studies are crucial to furthering our mechanistic understanding of hillslope hydrology, but are incapable of revealing the influence of longer term climatic controls on hydrological regimes. The influence of inter-annual variability in precipitation on the hydrology of a small boreal headwater catchment was studied over a two year period. The first year had lower than average precipitation marked by a particularly dry spring, resulting in a completely different hydrological regime from the following year, which had higher than average precipitation. The spring runoff event was completely absent in the dry year due to a 19% smaller than average snowpack and a dry April. The small spring recharge, coupled with 30% less summer rainfall than the wet year, resulted in up to 20% lower upland soil moistures, a virtual absence of saturated upland soil conditions, and peatland water tables that were routinely more than 10 cm below the peat surface. The increased catchment storage capacity and lack of hydrological connectivity in the dry year resulted in 68% less total runoff from the catchment than in the wet year, reversals of peatland groundwater hydraulic gradients and the absence of runoff mechanisms observed under the wetter conditions in the second year. The high degree of inter-annual variability in hydrological interactions among catchment units demands careful consideration in any study of not only catchment hydrology, but also biogeochemical cycling in the boreal landscape.
Bibliography of Canadian Geomorphology