I'm by no means a geologest, but I do cave with a lot of them. The area around Glennwoood has held cavers interest for many years now. There are quite a few different hot springs in the Glennwood area, from Dotsero, to South Glennwood canyon, with several up valley toward Aspen. They could all stem from the same heat source several miles below the surface. Over geological time, they have moved around some as erosion and other forces change their outlets. The area that is most active right now is around the pool area of the river. That area, even during high water is considered flat water, if memory serves my right. So I'm not sure how much scouring the river causes right there compared to in the canyon, where the river bed sees a more constant change in flow and rock movement. The canyon is basically a large fault that the river has followed for a long time. As the river and springs intermix as the canyon was cut, many caves were formed due to the mixing of spring and ground waters. Caves were formed throughout the canyon in the soft and easily dissolved limestone deposits in the canyon. Yes a very interesting topic in deed.