Canadian Canoe Routes

River gradient and river grades
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Author:  DCamp [ September 2nd, 2008, 9:48 pm ]
Post subject:  River gradient and river grades

I was wondering if anyone had any opinions on what typical river gradients are for a given grade. I know that gradient is a rough measure for grade, since the actual grade is largely dependent on local conditions.

I am curious because I am looking into a trip which I don't have any info on. The river looks OK on good resolution GoogleEarth images, but it is a relatively steep river (braided, ranges from about 5 to 10 m/km gradient).

Author:  paddlenorth [ September 3rd, 2008, 12:32 pm ]
Post subject:  Re: River gradient and river grades

Total volume makes a big difference. I think the Colorado River through the Grand Canyon is around 10-15 ft/mile, but the river is so big, these rapids are enormous.

It makes a huge difference if the river is a constant grade, versus the other extreme, pool and drop (nearly flat paddling with rapids/falls in between.) A truly braided river always has a fairly constant grade because the river bed is sand and gravel.

I don't know B.C. rivers, but I would look for a similar size river with a similar gradient in B.C. that people do paddle nearby,
these is easy to do using Google Earth.

I'd look at the aerial photos and topos to look at the number of rapids. 5-10m/km is steep by my experience, but not out of the question. On a steep gradient I'd rather see lots of rapids rather than only a few, b/c few rapids means they're likely falls.

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