There is a trail of sorts along the west bank of the Duwamish River that takes one underneath the 14th St. Bridge. Along the trail you can see 7 foot tall fennel and the remnants of homeless hangouts; the odd assortment clothes, food packaging and charred wood. In these photos you can begin to get a sense of the level of disrepair on the bridge. Link to the Bridge Project webpage is here.
At low tide on the Duwamish River even small, pleasure boats seem to stir up the muck, for lack of a better word. You can see discoloration in the wake as it reaches shoreline.