Image from this page. More there and lots more if search Arroyo Seco River California and click Images.
Communicated with Keith and Leslie at Jamesburg about this and they say that yes it's the same spot where I and others have walked and swam up to - sometimes hiking there from Tassajara. That makes me wonder about the NY Post article saying the waterfall is 40 feet high. Not the one we see from below. That's ten to fifteen feet as I remember it. So either that's an exaggeration or there's more falls above what we could see from below. As one approaches the falls, they can't be seen. One enters a roughly oval pool maybe 25 feet wide and fifteen feet across and the falls are not straight ahead but over to the left. The pool is surrounded by walls but maybe there's enough rock to sit or stand on over to the right. It's deeper where the falls come in. It's so unusual for there to be a lot of water this time of year. I always called it a National Geographic quality walk/swim. Some neat pools on the way where the creek/river narrows. Recall jumping from boulders into the pools on the way there. There are even larger boulders and pools further downstream from the Horse Bridge that tend to have more people frolicking. Would love to go back there.