Wandering Miramichi rivers, New Brunswick, Canada
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文摘
Six rivers within the Miramichi basin of New Brunswick display long sections with multiple channels that surround semi-permanent islands, linked by single channels. This type of anabranching river may be termed wandering, displaying a similar planimetric pattern to wandering rivers in western Canada. This research addresses three objectives: (1) to provide a detailed description of the location, pattern characteristics and boundary conditions of wandering Miramichi rivers; (2) to compare the pattern characteristics among wandering rivers within the Miramichi basin and to other wandering, meandering and braided rivers; and (3) to investigate formative processes for wandering Miramichi rivers. Wandering rivers within the Miramichi region occur in larger valleys located downstream of an abrupt change in bedrock from resistive to more erosive bedrock lithology. Larger rivers display greater braid indices than smaller rivers. Wandering Miramichi rivers display more similarities to meandering rivers than braided rivers, exhibit an anabranching pattern, yet have characteristics markedly different from anastomosed rivers. Energy levels, mid-channel bar formation, migration rates and width–depth ratios are all within the meandering range, lower than braided and higher than anastomosed. Once anabranches are created, larger rivers apparently maintain a greater number of anabranches because of greater discharge. Wandering Miramichi rivers may represent another anabranching river pattern type, different from anastomosed and previously described wandering rivers.