The answer is NO, even with the damaged spillway!! There is so much misinformation and misunderstanding regarding the emergency spillway. The emergency spillway is only there to protect that dam in case of an "act of god" inflow, where the concrete spillway is running at full capacity of 260,000 cfs and the reservoir is continuing to rise above 901. The concrete spillway should be designed to handle the probable maximum flood, which is a calculated inflow hydrograph based on extreme precipitation, saturated watershed and runoff coefficients. This would be routed through the reservoir to determine spillway capacity requirements. This event should be so extreme as to be unlikely to occur in nature. But of course there are "act of god" events that nobody can predict or calculate. For example back to back events without an opportunity to reduce the reservoir flood pool level back down to the rule curve. There is a "controlled spillway maximum" of 150,000 cfs which is just an administrative agreement to control downstream flood levels. The decision to reduce flow in the concrete spillway was not a good one. The operators should have been aware of the consequences of using the emergency spillway and also should have been aware of the foundation conditions along the horizontal section of the chute and the steep section at the end. They had time to start clearing trees below the emergency spillway so they should have had time to determine that there really was only one operational strategy and that was to use the main spillway to prevent the 901 being reached. They will not make that mistake again.With so much attention being paid to the 2005 license renewal requests for armoring the emergency spillway, it seems prudent to ask, "If the primary spillway was not damaged, and running within the operational guidelines during the heavy rains leading up to the overtopping of the emergency weir, would the reservoir level have reached El.901?"
Thanks in advance for anybody here would like to undertake that opportunity.