The Flume Trail, as its name suggests, follows the path of an old wooden flume [remnant shown at left] that was used to carry water from various creeks draining the Crags to the town of Castella, near the Park Headquarters.
The lower part of the trail can be accessed from the western end of the Indian Creek Nature Trail Loop. A few hundred yards "counter-clockwise" from the upper bridge, a sign marks the start of the Flume Trail. This is a great hike on hot days as it is heavily shaded.
Hiking west the trees seem to have dark brown or almost black trunks, especially after a rain, but on the way back it looks like a totally different forest — the trees look green with their moss-covered bark and you'd swear that you'd never hiked along here before.