Sunday, May 27, 2012

Gradient (ft/mile): elevation vs. distance plots

The Local Anchorage Creeks:
The Mat-Su Regulars (Little Su, Upper Willow, Kings Magic Mile)
The Talkeetna Fly-in Creeks (Disappointment, E Fork Iron Ck, Damnation):

The mid-Alatna Valley Creeks:
The Arrigetch Creeks:

I have been using Spruceboy's USGS maps over Google Earth to estimate gradient, then R to make some contour plots of local steep runs and some creeks in the Arrigetch-Alatna Area. Too satisying.

I should have gone paddling, but no, I made these graphs instead.

They are pretty informative and suggest that the Arrigetch offers up the closest to California style granite creeks we have in Alaska. What makes the Arrigetch unique is the paucity of glaciers combined with steep glacial carved terrain, much of it above tree line and so wood free.

It looks like the two local boofy-creeks, Lower Ingram and Upper Willow, aren't as overall steep as they feel, while the granite boulder garden creeks, Little Su and Kings, are steep. This holds for Disappointment and E Fork Iron, too, as Disappointment is not as overall steep as East Fork Iron Creek, surprisingly, but is bigger volume and more pool drop. So pool drop, ledgy creeks hide their steepness on these gradient plots, while boulder garden creeks tend to be steepest.

All the kayakers already know this, of course, and this is just like a little homework assignment to see that clearly.

The Aiyagomahala Creek (aka Hot Springs Creek or South Arrigetch Creek) is super steep at top where it's full of slabs and slides and waterfalls. Just above its hot springs it's a boulder garden, like Magic Mile. Upper Awlinyak, I have not yet seen, but I expect that it is a gorge full of granite blocks, like the the Deceptive Pass branch of Awlinyak. Arrigetch Creek is least known to me. It's hidden in the bushes and glimpses I get of it are broken gneiss, rather than boulders.

All the little Alatna Valley creeks offer up a bunch of variety. None seem too hard for beginners, except the inner gorge of Nahtuk, which I have seen and expect to be Class III+ if not IV. Unakserak and Kutuk look like class II, maybe some wood, and Pingaluk is Class III (walked that a couple years ago). Awesome game trails in the Pingaluk. So a basecamp in the Alatna valley offers everything from Class I on the Alatna to Class VI in the Arrigetch, all in a ten mile radius.


  1. The first time I ran the Little Su. I was suprised at the steepness of that one section, I believe after Death Ferry, and went up with my GPS and found that it is indeed really steep in places. Those charts are great Roman, thanks for compiling all of this useful information for other boaters like myself to use.

  2. My pleasure Mark. Hope you're buttboat is treating you better.


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