The creek (or, in Los Angeles, river*) was very clear, and somewhat reminiscent of the awful swamp in Lord of the Rings (without the corpses):
And yes, those are the Sawtooths in the background:
*You've seen the Los Angeles River in chase sequences in movies. Concrete channel with either no water or a few puddles. In 1920s L.A. high school yearbooks, "Yours until the Los Angeles River wets its bed."
Not much elevation difference, but enough to remind you what the differential does to a weak water bottle.