When I hiked through there ( Horse Spring Campground ) some years ago I did not find the " horse spring ", which I gather is where it got its name. On the west side of the campground I did see some wet ground with grass which indicated some water but it looked like something that would just dry up in the hot months. The upper end of one of the canyon arms of Arrastre Canyon ends up near that camp ground. I found evidence of Cougar presence, and lots of Deer tracks are all over in the more quiet remote ares of those canyons. I also found in a dense grove of very big Oaks a small spring that was clearly used regularly by the local wildlife, with various trails coming to it from different directions