We’ve past high flow for the year, and the boulder didn’t shift.
On April 15th it was covered,
and on March 23 the water was about the same level as it was today. It’ll take a heck of a season to move that rock downstream.
The railroad bridge in Durango was swept away in the flood of 1911, and was rebuilt high enough to be safe in a hundred-year flood… if the flooded river just carried water. But water high enough to toss this boulder downstream would take out a few trees, and it would float away some of the trailers in the floodplain upstream of the bridge. Next time there’s a big flood, the water won’t take out the bridge like it did in 1911. Instead, the build-up of trailers knocking against the bridge would likely tear it down. The older I get the more it seems that it’s not the journey that’s the problem; it’s the baggage.
We think of streams and rivers as fixed features of the landscape, but they’re not. Trees continually fall into the water because the banks are always moving laterally (unless the streambed is artificially restrained by riprap or levees). A river is constantly shifting because of the way water flows.
Water that flows in a river moves like a corkscrew, twisting in on itself. Water flowing at the bottom of the river is slower because of the friction between the water and the riverbed, while the water on top flows faster. When a river bends, the faster water on the surface pushes against the outer banks and dumps trees into the waterways, while the slower siltier water at the bottom slips to the inner bank and drops some of its sand or gravel.
Most of the waterways we see are controlled by dams, where the high flows are moderated and the trunks are removed from the river. Here we have a natural stream in the spring, sweeping great trees downstream.
This is near the start of our walk, with tree trunks piled at the point of this little instream island.
Next we have this log caught midstream a wee bit upriver.
Big logs collect smaller logs and branches,
and you can see that the water was much higher a few days ago, when the flow around the near side of this tree caught a bole and a lot of small branches.
By midsummer, this torrent of snowmelt will have faded to a babbling brook. This huge trunk will be immovable… until next spring shifts it downstream again. By nature, a stream is a messy, trunk-littered path.
We know that the beavers moved in because of their nighttime handiwork.
and it’s pretty easy to see where they’re staying. It’s a streamside burrow with two entrances that they live in until they build their dam, fill their pond and build a lodge. It’s their starter home.
The main entrance is right in front of you, made of peeled branches woven together.
The other side of the same pile shows a second entrance, while the beaver’s backdoor route is all the way over by the pile of peeled sticks at the far end of the bench of soil. There’s likely an underwater entrance on this end, and a series of underground rooms dug from here to that far pile.
This is the back door entrance on the far end of the bench, with an underwater entrance on the far end as well. The beaver’s first rule of home construction is: always have an alternate exit. Some animals fight off intruders, but beavers build a back door instead.
This pair is in a streamside burrow for now, but they have big plans. At night they’re consumed with construction problems, but during the day when they sleep they might dream of their dam and a litter of kits. Of the day when they have a proper lodge in their own pond.
This might be the beaver’s dream.
(This lovely illustration is from a book written by the Islamic scholar Harun Yahya titled Devotion Among Animals: revealing the work of God Ch.2 Awareness in Animals: One of the dead ends of the theory of evolution, Fig 5.) (I’ve gotten in trouble for using this illustration in lectures because people assume that I must renounce evolution to read antievolution tracts, but honestly, I’ll read anything.)
A pair of beavers started engineering this area this spring. This is the view from one end of their clearing
and this is their clearing from the other end.
Without exception, all of the cottonwoods have been cut to fall at right angles to the river. I think at least 30 big trees–between one and two feet in diameter–have been cut here. There are hundreds of little trees gone, but you don’t notice them because they are taken away.
When they cut big trees, it’s a multi-step process.
First, they sit up on their hind legs and chisel their way around the base of the tree until it topples.
Then they go up to the top of the trees and trim off the branches from the top down.
Sometimes the tree doesn’t fall just the way they intended,
but mostly it goes exactly as planned.
This clear-cut is as deliberate as if someone cut this wood for a lumber mill (although since it’s cottonwood, no one would’ve bought it, and the beaver do a cleaner clear-cut than humans: they don’t leave slash piles that need to be burned).
When you consider that this is a project that likely a new pair started this spring, you can see that ”busy as a beaver” might be nothing but the truth.
I have a particular fondness for beavers. I am probably the only person you know who keeps a stuffed beaver in her bedroom
which is why you’ll hear more about beavers tomorrow.
The cottonwoods beside the stream are leafing out in an unearthly shade of spring green.
They’re almost fluorescent.
There has been an orderly melt this spring, with plenty of cold nights. Runoff is supposed to peak this month, and the water is running clear now.
Six weeks ago at the same spot (March 22) the water was higher and siltier, and there wasn’t any green.
Love that green.
This is our stream, swollen with spring. Right in the foreground is a boulder under the water. There is a dip in the water before the boulder, and a tail of white water behind it… and otherwise it’s hidden.
This is the same place 3 weeks ago. This boulder is why boaters get so good at reading the river.
Three weeks ago you saw it,
and now you don’t.
In some areas, the snowmelt reveals unexpected surprises. This road was closed for the winter, and it’s the first time I’ve been here since fall.
I get a kick out of gravity. It’s so predictable.
This rock is so big it’ll take heavy equipment to move. And when I look up,
it seems like that rock might not be lonely much longer. I move right along, since I definitely don’t want to be standing under this many tons of stone, soil and tree. No thank you.
Across the river, the slope is made up of decomposed shale, which repels water.
It’s a peculiar material, because that water-repelling quality makes it hard for plants to get their roots down. This slope isn’t recently denuded; it’s been that way for ages. It makes for an odd riparian edge.
Another dog joined us back a mile ago, and now I see why: it’s not just fallen rocks that the snow left behind; it’s fallen deer too. This dog has visited this carcass before, I think.
My dog was so happy to be able to help.
Today, the stream looks like a little river.
This is a photo taken three weeks ago from the same location, different lens. The local meltdown is happening fast, and there’s quite a lot more snow in the high country.
This shot was taken where the deer were crossing this winter.
The water has risen, and is rising still.
Meltdown has begun! The streamflow is starting to increase, and the water is brown with silt.
Two weeks ago the creek was still bridged with ice, but now it is running free and starting to rise.
Doesn’t the word redux make you wonder?
re·dux /rɪˈdʌks/ –adjective
| brought back; resurgent: the Victorian era redux. |
[Origin: 1650–60; < L: returning (as from war or exile), n. deriv. (with pass. sense) of redūcere to bring back; see reduce
]
Dictionary.com Unabridged (v 1.1)
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2006. |
We’ve had steady warm wind for a few days, and the snow is disappearing. Yesterday, the stream opened up. Those tracks are from a dog or coyote that’s walking on top of the snow; the deer still can’t get through here.
A week ago, it looked like this:
and I was floundering around to my waist in snow; this week the snow is no more than knee high and it feels as though Spring might be dreaming of waking up.
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