Field Day to the Molalla River

I got asked to go up the Molalla River to check out a large log jam that formed a couple months ago following December rainstorm flooding.  It was really interesting because the stream gage on the Molalla River lost a signal during the peak flow event in December, but the data on either side of the missed peak wasn't indicative of a super large flood.

As we drove up the river, everywhere we stopped seemed to confirm the relatively benign flows of December with flow indicators all right at the bankful stage which corresponds to what the stream gage recorded at about a 2.5-3.0 year flood event.  But then we got to Horse Canyon where the log jam formed which was really impressive.  Logs were washed together and piled 30 feet in the air at the entrance to "The Narrows," a natural bedrock constriction of the channel.  Some of the material clearly just floated in, but some of it is standing vertical and I'm not sure how the stream could have had so much power that it stood logs upright!

And the really interesting thing is that as we continued further upstream, there weren't any indicators of hung up logs or stream bank damage or debris flows from tributaries.  It's almost like there was a dam-break episode that released all the material at once and conveyed it in one giant slug of water to the canyon where it all hung up.  But even that theory doesn't hold up because there is no evidence of flow above the bankful width elevation!  Regardless of how it formed, we can see where it ended up and now it's blocking the river and kayakers are complaining and asking the BLM to remove it.

In other news, a few co-workers and I went out for beers after work one day and on another I cooked some amazing ribeye steaks with gorgonzola mashed potatoes!