Kiewit will need to construct "transition sidewall" slabs in this section to meet up with the RCC. It will be interesting to see how they perform this "meet up" in the sidewalls.
The other picture below is of the sidewall drain pipe they are preparing in the sidewall rebar. Clearly the original upper spillway will have seepage that requires drainage, besides the existing longitudinal drains for this section. Whether Kiewit connects other newer slab drains to sidewall drain pipe(s) in the upcoming construction should be revealed (perhaps in later seasonal work).
Drone footage has shown that the lower concrete section of the spillway has "open" drain pipe on the outside of the base of the sidewall slabs. It is not clear what the final drain design approach will be for this section. I've been waiting to see more clues.
"wedges" at the sides of the transition slab inferred to be construction "fill concrete".
Sidewall drain pipe being placed in rebar matrix before pour (upper main spillway).
