First one looks to me like Oregon or Sierra. Dorsal stripe does not look distinct enough to be Mountain or Valley.
It is hard to tell though.
Without better pics, the only way to tell (between Oregon and Sierra) is locality: http://www.shastaherps.org/map/AquaticGarter.svg
(above map won't work in IE < 9 but works in almost every other browser - Oregon is subspecies of Aquatic)
Herp in Shasta County often?
Based on the map, I'm calling it an Oregon Garter.
My wife's family has a farm and some land in Shasta Co., so we try to get up there a several times a year to chill out and get a good dose of nature. Whenever I'm up there, I can't help but do a little herping, mostly on their property, but I've ventured out to some other locales. The way I look at it is, whenever I'm hiking--I'm herping, and I try to do a lot of hiking when I'm up there during the spring, summer, and fall.
I want to make my way up there pretty soon, as things are starting to warm up. When I plan my next trip, I'll post to see if anyone in the area wants to do a little snake snooping.