Have you recently seen foam in Bear Creek and other tributaries?
If it looks like the foam in the first two photos, never fear! As plants decompose, they release oils that float to the surface of the water. As the water moves downstream over rocks and other obstacles, air is introduced to the water and plant oils, creating a foam. Foam will be found downstream of turbulent creek or river sections.
The foam seen in the last photo is from the presence of detergents in the water. If you see something like this, report a complaint to the Oregon Department of Environmental Quality (https://www.oregon.gov/…/File-Pollution-Complaint.aspx) and inform your local municipality’s water or natural resources department.