Geologists of Jackson Hole's video: Flood plain dynamics along rivers in the western USA

Presented by Mike Merigliano, University of Montana Although we rarely see it happen, rivers move. They not only move water and sediment downstream, their channels shift side-to side, meanwhile storing sediment in flood plains and terraces. In a natural system, today's fish habitat could well be an ideal place for birds tomorrow or centuries from now, as channels and flood plains trade places in time and space.  Channel migration rates and related flood-plain creation, storage, and loss can be measured using the areal distribution of cottonwood ages.  This information indicates the stability of channel and flood plain systems, including vegetation, and in turn, animals that depend on riparian vegetation. Much of the plant diversity on flood plains and terraces follows the topography and soil characteristics laid down by the river over time. This presentation will show many examples of dynamic flood plains and channels, the corresponding vegetation, and conservation issues related to flow-regulated and bank-stabilized rivers in the arid western United States, including the upper Snake River. The humankind-imposed constraints on the natural migration of rivers within their flood plains has enormous implications for those living near them, alongside them, and certainly downstream from them.