Gate to Upper Mill Creek only open between July 1st and November 1st. Bikes are allowed on this trail only on even-numbered days. Usage fee of $3 per vehicle is required upon leaving the canyon. Well worth it.
Big Water is towards the top of Mill Creek Canyon and provides access to a number of higher trails.
It is also very nice buffed out singletrack in its own right.
There are two trails starting at the parking lot. The trail to the right is Lower Big Water and the left Big Water Trail (Upper).
The trails climb though stands of old-growth pine and aspens. Buffed-out singletrack, bridges, creeks, and a gentle climb up to the intersection between the Big Water Trail, Wasatch Crest trail, and Dog Lake trails.