When I used to go to DCHS, there was one man-made item that was left there semi-permanently and which I thought was not only acceptable but a great addition: A length of PVC pipe that had been shoved into one of the sources of hot water on the cliff, allowing for the hot water to fall like a shower about 15' to the creek below. It made that area of the creek also warm, and we could choose the temp of the water we wished to be in, in the creek, by just moving closer or further from that area in the creek. Plus, the "shower" doubled as a great hot water message for the shoulders, back, etc. It was better than a jacuzzi jet.
Is that "shower" still there?