That's a fairly ominous yellow caution sign. I wondered what that fine print Orange County County Ordinance 2-5-43(b) meant. So, I looked it up and here it is:

Sec. 2-5-43. Bicycles. (b) Unsafe Operation. No person shall operate a bicycle in any manner that endangers any person or animal or at a speed that is greater than is reasonable or prudent, having due regard for other users and the surface, width, and grade of the road or trail, and in no event in excess of ten (10) miles per hour, unless a greater speed is posted.

I made my way to the Villa Park Dam cache and then headed into the Santiago Oaks Regional Park with the plan to get the Some Dam Cache cache at the Barham Ridge Lookout. On my way I spotted this spillway spot and it felt like it needed a cache.

When I got back I discovered I illegally parked (the No Parking sign was/is completely covered by plants), but the EV-Geomobile was still there so there's no more to that story.

There's parking in the Santiago Oaks Regional Park and there's likely parking near the trailhead I used, just a bit farther away. The trail up to the cache from the park is steep, hence the aforementioned warning sign. It's a slight grade coming from the trailhead I used.