More than you ever thought you wanted to know about the Tualatin:
"The dam," which provides a diversion of Tualatin River water to Oswego Lake, is, perhaps 1/2 mile downstream from I-205. Be prepared to paddle upstream, hard, if you approach it during high, winter water.
Originally, freight was steamboated up the Willamette to Sucker Creek, (now prettily known as Oswego Creek,) the outlet of Oswego Lake. From there, merchandise was portaged up to the lake, then transported via apparently very skinny steamboats across the lake and through the artificially created narrow diversion canal to the Tualatin and, from there, upriver to Hillsboro, Forest Grove, etc. Unfortunately, this engineering scheme was accomplished just about the same time that railroads arrived and made it all economically non-competitive. Reportedly, between the endless oxbows and snags, walking was almost faster than riding the boat. Check out the book "Willamette Landings." Fun reading if you enjoy exploring the area's history.
Every year or two, some yahoos boat over this dam intentionally or accidentally. During late summer low water you can paddle up to it from upstream and step over it. During higher, winter water, you'll discover how deadly low-head dams and their reversal waves can be. Oregon and the West don't seem to have nearly as many of these as the Midwest and East Coast. I don't recall any fatalities but I guess we've been lucky. It's only been a year, I think, since the last pair of Darwin-wannabes accidentally tried it. There's a fish ladder around it. There's also private property all around it and no good, safe, legal way to pass it.
Downstream from the dam, toward "the ballpark" and West Linn, the river is hit-and-miss flat water and rapids. I've seen a gorgeous Wonacott wood strip canoe crunched shortly downriver of the dam during low, rocky water. That same stretch is bouncy and fun during the winter. There's a reasonable takeout on the left bank at Borden Road, but where do you put in, safely and legally? From there downriver to the mouth it's mostly rocky during low water. It's mostly big waves with unforgiving intervals in-between during high water. The first two canoe teams I know who tried it ended up swimming. One of them had their new canoe rescued by a powerboat just before it went over Willamette Falls.
With advanced skill levels and bomb-proof "Tupperware" plastic boats it's probably not as "deadly" as it once seemed but it's still not a place for the inexperienced.
Coho salmon, steelhead, and trout all inhabit the Tualatin system. "Nowadays," they're pretty much all protected from fishing as endangered populations and illegal to pursue but I see them now and then on the river and keep cheering for their resurgence. I suspect the main Tualatin (Can you say "Lee's Falls?") and Gales Creek are the primary spawning tributaries but Dairy Creek, McKay Creek, Johnson Creek, Beaverton Creek, what's left of Scoggins Creek and, certainly, much-abused Fanno Creek and Tualatin's Hedges Creek are original homes to some of the most gorgeous, big, black-spotted cutthroat trout you'd ever hope to meet. ("I've seen 'em." ) :wink: