However, the erosion debris field reveals how materials became collision shatter instruments from the significant forces of hydraulic turbulence in the blowout flow (canyon). Thus, all of the broken spillway concrete, all of the highly fractured weathered rock, and even ultimately "shattered" pieces of the amphibolite essentially "jackhammered" a "fresh rock erosion" down the canyon.
Throughout all of the geologic reports, the definition of "fresh rock" and "adequate bedrock" applied to the hard amphibolite (and was noted as Amphibolite).
The article discussed “building an angled flip just above the collapse site”, not at the end of the spillway.