Hello and thank you for your report, and apologies for the late reply. This looks to me like a native aquatic garter snake, which are found in this area. They are harmless to people. You can learn more about Oregon's snakes from the OR Dept of Fish and Wildlife: https://www.dfw.state.or.us/wildlife/living_with/docs/LivingWSnakes.pdf
Regards,
Lindsey

Lindsey Wise
May 23, 2022, 5:40 a.m.