Arroyo Hondo east of San Jose
Arroyo Hondo creates the deepest gorge in the bay area, a land feature that is dramatically visible from airplanes. Like many Arroyos, this one also has access problems. The put-in is along a remote road on the east side of Mt. Hamilton and currently uncontested, although parking is sparse. The take-out is on Calaveras reservoir, where boating is officially forbidden.
The county maintains a dirt road that crosses this creek near the gauge that measures Arroyo Hondo flows (AHD), but the road is gated far away from the river, and the climb out of the canyon makes it an unattractive take-out.
The original AWA California river inventory claimed that this run is 8 miles long, but it is actually about twice that. Reports also said it contains class V drops with some tough portages and a high (perhaps 60') waterfall that fortunately has an easy carry.
A group of us ran this on December 26th at 225 cfs on the AHD gauge. We all thought that flow was very acceptable, possibly on the lower end of a medium flow for hardshells. This was enough water to get through most of the rocks while retaining eddies in between, and not pushy.
The window of opportunity is very short on this run, because the flows rise and drop quickly. The gauge is towards the end of the run. We guessed 3-4 hours for water to arrive at the gauge from put-in.
If you are interested in this run, it would be a very good idea to have a shuttle driver, and to scout the put-in and take-out in advance so you (and your driver) are familiar with the logistics. The shuttle is long and winter daylight hours are short. Nevertheless we saw one parking spot near put-in that seemed legal, but we did not see any legal parking spots near the reservoir.
For put-in on Kincaid Road, it would be wise to suit up in advance, so as not to linger near the bridge over Isabel Creek, because rumors say that boaters are not welcomed there. For take-out, the best alternative seems to be a boat ramp near a lighted building, then up a dirt road west of the dam. Cellphone signals are not available on the reservoir. (nor presumably anywhere in the gorge) so the best plan might be to wait until dark to cross the main reservoir, and ask your shuttle driver to arrive shortly thereafter.
This run has plenty of hazards, including willow mazes, undercut rocks, and a logjam. Boat cautiously. On our 2010 trip all hazards could be avoided or portaged, at least at the flow of 225-250 that we had. The run is long, so get an early start!
Map of Rivers