Sunday, December 7, 2014

The river

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I live next to a river and have about 1300' of frontage on it.  It forms the northern boundary of my land, and is quite pretty.   At this time of year it rises and lowers pretty fast, and pretty dramatically.  I can get 9 to 10 vertical feet of water rise on this river over a 6 hour period.  It's the closest thing I've come across to a flash flood sort of situation in washington state.

It's caused by very, very heavy rainfall that hits the mountains to the east of me.  This river is the drainage for an area that in the fall, winter and spring will get 5 to 10 inches of rain in a 24 hour period, over and over again.

The worst combination is when we get colder weather, and a few feet of snow.  Follow that with warmer weather and heavy rain on top of that snow.  At first the snow just sheds the water, but if there's enough rain, all of the snow and all of the rain all come down the valley at once.

One of the local indian tribes is looking to relocate their reservation because of this sort of pattern; they expect it to worsen over the next few decades, and I cannot blame them for not wanting to be washed out to sea.

Mostly I can watch the river do its thing without it bothering me.  Sure, my fields may get some water on them, but nothing there is hurt by the seasonal flooding, and maybe it helps the soil.  it's been happening for thousands of years.


The only issue i've got is in the corner of my property with the red circle.  The river is coming down a straight section there and hitting the bank pretty hard, eroding it.  What's there is hard blue clay -- pretty water resistant stuff, but every year it looks like it loses a few feet.

here's a closeup of the  river bank, and the red line is where the shortline used to be at some point in the past.  The tree that is at the top is actually about 25' out from the bank, on its own little island.  It'll be floating downstream pretty soon.

Traditionally the cure for this sort of erosion would be to reinforce the bank; dump rocks or rip-rap or  other stuff into the river at that point to make it resistant to the water, or at least slow the process down, but that practice is now outmoded.  I can do something like put coconut husks there (really.  that's what they will approve) or I can plant stuff according to the department of ecology.  But I got a more interesting suggestion from the corps of engineers.

"Well, you know what an ecology block is, right?"  yes, the large concrete blocks that they make at concrete plants when they have extra concrete.  But I thought I couldn't put those (or any other impervious stuff like rocks) into the river.  "You don't put them in the river, you stack them at the edge, and if they happen to fall into the river because of flooding erosion, well, that's too bad.

I guess it's all in how you look at it.

1 comment:

Nick Keenan said...

I'm starting to worry that you haven't posted since this.