Page - 110 - in Book of Full Papers - Symposium Hydro Engineering

weathered to decomposed rock previously mapped within the chute itself had been scoured away. Figure 4 A. Geologic map of FCO Spillway Chute showing initial concrete failure location [6]. B. Aerial photo showing pre-1960s-construction exploration locations [5]. However, on the right side of the chute’s scour hole, there was an area of intensely-weathered rock that continued to ravel into the scour hole during the Spring 2017 FCO Spillway releases. These disparate exposures raised questions about the continuity of rock weathering and indicated that the presence of cross- 110