Re: [Paddlewise] Tides and Current Speed

Craig Jungers wrote:

> All I am after is someone who has gathered data on a relatively simple 
> tidal narrows indicating just how fast the current ramps up to full 
> flow. I'm pretty sure it's closer to a rounded square wave than the nice
>  clean sine wave shown on all the tables with graphical representation
> of current speed.

The curves in my Tides and Currents program for locations on the lowetr
Columbia River are clean sine waves for some locations and skewed sine
waves for others, all drawn from NOAA data and modeling.  I would not
characterize any of them as rounded square waves, but they are not for
spots like the ones of interest to you.

I agree a rounded square wave is a better representation of reality than a
sine wave for typical tidal narrows spots.  Certainly folks who have
waited around for "high slack" near Nakwakto Rapids and similar passes know
that, know to compensate from the NOAA (etc.) graphs.  I think all you
need to do is broaden the centers of those plots a bit and you are good to go.

I thought you said you wanted the max current as a function of the "tidal
range."  The max current will not be a simple prediction from tidal range,
for the reasons I cited last post, principally area of the basin on the
upstream side of the narrows.  But you read the post, so you already know
that, I expect.

-- 
Dave Kruger
Astoria, OR
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