At the end of the spillway the water is send upward. This is a way to dissipate the energy of the water coming down and avoid digging a hole or eroding the river itself. This appears to be a common feature in most spillways.
http://media.fishreports.com/reports/img-20170303-78a7bb40.j...
Hard to comprehend how massive those blocks are...
Juan (blancolirio) posed a very good time-lapse/montage (including footage from the DWR) that shows the entire repair project. The audio has comments from Keiwit's executive project director of the repair project about the insane amount of material and work that was needed.