Craig Jungers wrote: > Does anyone have any links to any data that actually correlates current > speeds with tidal range in a channel? No. Because you also need to consider the momentum associatedof the water mass as it moves toward the constriction ... and the bottom topography ahead of the constriction. In short, there are more variables than just tidal range, although it is certainly an important one. Think on how the flow through a shallow, narrow "overflow channel" will be massively affected by small changes in the height of a large area of deep water adjacent to the channel. If the channel is the only outlet (simplest case; multiple outlets just complicates the math but conceptually is the same game), then a small rise in the water level adjacent can give rise to a huge current in a short time in the shallow channel. But, if the adjacent body of water is small in area, the same rise in height will produce a smaller flow in the channel because a much smaller amount of water needs to get through in a given time. And, variations in channel depth (related to cross section) from location to location will also give different currents through the differing channels for a given rise in tide. Places like Nakwakto Rapids are very narrow and adjacent to large bodies of water ... and they experience helacious currents for a given rise in tide compared to channels not as narrow adjacent to same-area bodies of water. Nakwakto: http://www.mobilegeographics.com:81/locations/4028.html -- Dave Kruger Astoria, OR *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Tue Oct 27 2009 - 21:23:25 PDT
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