DAMMING JAMES BAY: II. IMPACTS ON COASTAL MARSHES

The damming of James Bay as proposed by the grand Canal Scheme will influence the hydrology of the coastal marshes. The salinity regime of two James Bay marshes were compared to understand the processes that govern salinity in the zone near mean high water (mhw) and to predict changes that may result from this proposed impoundment. Data suggest that sites along southern James Bay would be minimally affected because of the current low level of salinity. The northern marshes would, however, experience significant changes, as their primary source of salt is from saline tidewater. A simulation of the vertical salt and water fluxes at a northern location predicts a rapid reduction in the chloride concentration at mhw, which should approach the present values for southern James Bay in about 10 years. Above mhw, the salt will be leached quickly, so that within four years the surface chloride concentration will be reduced to the level currently found in southern James Bay.     

Progress in Canadian Geomorphology and Hydrology 1996–2000

Since 1996, a broad range of publications has been produced by Canadian geomorphologists and hydrolo‐gists. These publications have been distributed in journals with national and international circulations. Although there remains a major focus on the study of observable processes in fluvial, aeolian, coastal and slope environments there is also a strong, historical component to explanations oflandforms, landform assemblages and sedimentary sequences. Some of these histories have incorporated the effects of high‐magnitude (catastrophic) events, some of which may have no modern analogues. Perspectives on the interactions among microclimatic variables, including changes induced by human actions, continue to evolve. Forest clearance and its effects on evaporation rates, water‐table levels and timing ofsnowmelt, the human use of wetlands and release of methane and carbon dioxide, will continue to demand the attention of scholars interested in explaining future climatic scenarios. Depuis 1996, un large éventail de publications a été produit par les géomorphologues et hydrologues du Canada. Ces travaux ont été diffusés dans des revues nationales et internationales. Bien qu'il y ait encore une attention privilégiée portée à l'étude des processus observables dans des environnements fluviaux, éoliens, côtiers et de pente, il existe aussi une importante composante historique dans l'explication des formes du paysage et de leurs assemblages ainsi que des séquences sédimentaires. Certaines de ces reconstitutions historiques ont incorporé les effets d'événements de haute magnitude (catastrophique), dont certains n'ont peut‐être pas d'analogues modernes. Les points de vue sur les interactions entre les variables microclimatiques, et notamment les changements d'origine anthropique, continuent d'évoluer. Le recul des forêts et ses effets sur les taux d'évaporation, le niveau des nappes phreatiques et le calendrier de la fonte des neiges, l'utilisation humaine des zones humides et l'émission de méthane et de gaz carbonique, continueront d'exiger l'attention des spécialistes qui se penchent sur l'explication des scénarios climatiques futurs.     

DAMMING JAMES BAY: I. POTENTIAL IMPACTS ON COASTAL CLIMATE AND THE WATER BALANCE

The proposed grand Canal project calls for the damming of James Bay and the diversion of its water southward. This first part of a two-part study models some potential impacts on the climate, water balance, and growth patterns in the James Bay coastal zone. Use is made of a linear relationship of Bowen ratio and temperature, developed from studies of coastal wetlands in southern and northwestern James Bay and central Hudson Bay. It is hypothesized that changing James Bay into a fresh-water lake and disrupting its coastal currents would result in a delayed Bay ice melt of unknown length in the spring. Allowing a delay to vary between 0 and 30 days results in the prediction of lesser evaporation and greater water surplus. These differences in magnitude increase with the length of delayed melt, but in all cases are most strongly evident during the peak of the growing season. Colder and wetter conditions would have a strong ecological impact on all coastal areas of western and southern James Bay. In the northwest this could change the species composition of coastal flora, cause forests to retreat from the coast, and result in the growth of permafrost there.