Canyons are inherently risky. Flash floods occur without notice on sunny days. Technical skills & surrounding topography knowledge required yet does not eliminate risk.
Closer than Yosemite
Overview: A class 3BII canyon with as many as a half dozen short rappels, max height 50 ft.
Warning: This is a technical, class 3 canyon. Only experienced canyoneers should attempt this, you will need a complete set of technical gear (helmet, harness, rope, descender, etc) and the ability to build your own anchors (30 ft of webbing, quick links, etc). Canyoneering is a dangerous sport, avoid any time there is even the remote chance of rain or a flash flood. If you have low body mass, the potholes are cold and we got wet not quite waist deep, so be prepared. I am not responsible if you get in way over your head and get trapped!! Note: a few of the rope pulls could be tricky, so be careful.
Conditions: We did this on an 80 degree day in Phoenix and I thought it was nice in the canyon and a little warm on the climb out. My partner was quite cold in the canyon. I didn't think a wetsuit was necessary, but I was the one carrying all the gear and probably warmer because of it. The potholes were slippery but small and escapable without requiring special techniques or gear.
Hike: Park along the road and hike uphill until you reach the side drainage that allows access. Descend down the gully dodging catclaw and cactus. Continue downstream in the dry creek bed until the canyon slots up. You reach a slot in which there are several shallow potholes. Avoid them or slog through. You will soon encounter your first technical section. You can elect to rap up to 3 of the drops, else choose some class 4 or easy 5 climbs to get around these first few drops. Continue a little bit further downstream, maybe a quarter mile, and you will have pound out a few short 15-20 ft raps and then a multi drop sloping 50 foot rappel that is possibly downclimbable, but what the heck, rappel it! We found 3 bomber anchors in good condition but at two of the 5 rappels I had to build anchors using natural features. Please avoid bolting this canyon, it is not necessary. A final 15 footer and you are done with the technical stuff. An old jeep road can be taken from the creekbed on right LDC and goes back up to the highway and your vehicle.
Water Sources: Several potholes but nothing you'd want to drink
Camping: Not along the highway!
Check out the Official Route and Triplogs.