I stopped by Swift Creek in northern Whatcom County a couple weeks ago while heading elsewhere. I have several posts on Swift Creek that can be found by clicking on the label I assigned it. Whatcom County has a set of reports for those that want more info: http://www.whatcomcounty.us/513/Swift-Creek.
I took a short walk along the creek upstream of Goodwin Road. This reach like essentially all reaches of the creek has been agrading from the huge sediment load from the active landslide in the watershed and stream excavations have taken place to keep the stream passing under the Goodwin Road crossing as well as the Oats Cole Road crossing further downstream.
Sediment piles on bank
Cobble of serpentinezed mafic rock starting to crumble as veins expand from wetting and drying
More sediment removal stockpiles.
The reach above Goodwin Road is gravel and sand but there are pockets of fine sediment deposition.
This is the bad stuff: fine grained and thus subject to getting in the air and full of asbestos form minerals as well as poor chemistry for plant growth.
Whatcom County has been doing extensive planning on mitigating this natural slow disaster that has broad land use impacts. A proposal has been developed for building sediment capture basins. That scheme has funding in the Governor's budget and was funded in the State House budget. Funding was not in the Senate budget in May, but I have not been able to confirm if that still is the case.