Tuesday, December 20, 2022

Middle Roadside Falls

Continuing from the previous post, a short walk or drive south on the Columbia River Highway brings us to the next seasonal waterfall. "Middle Roadside Falls", which is another of the 'meh' names I made up just so I'd have some titles for blog posts. This one might be the tallest of the five waterfalls in the area, assuming you trust any of the height numbers I've been coming up with, which I'm not sure I do. The top (189.14' - 198.31') and bottom (64.93' - 86.06') points I came come up with once again give a height number that seems to be on the high side. As in 100-130 feet high, or technically 103.08 - 133.38, although I doubt the second decimal place is significant. I guess what I'm trying to figure out is whether my LIDAR-assisted guessing is any more accurate than the old-fashioned kind, and what I'm doing wrong if it isn't.

On the subject of whether to believe state GIS systems, the unnamed stream here (like the others nearby) appears on a state map of barriers to migratory fish. Which is technically true, but the entry here is just for the long culvert under the street, with no mention at all of the maybe-130' waterfall about a foot or two upstream of the pipe. So if anyone's divvying up habitat grant money sight unseen based on that dataset, it could lead to some really odd projects getting approved. At least the map has you click through a EULA first, agreeing that the data comes "as is" and isn't guaranteed to be accurate or complete or useful for any purpose whatsoever, which I guess is nice because nobody ever clicks though EULAs without reading them.

(The same dataset insists there's an 8' waterfall on Johnson Creek just west of Bell Ave. in Milwaukie, complete with a midcentury fish ladder, that as far as I can tell doesn't actually exist. But I haven't yet gone looking for it in person, and I may need to go do that just to be extra sure.)

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