Page - 143 - in Book of Full Papers - Symposium Hydro Engineering

making; (2) the lack of certainty about near-future inflows to Lake Oroville due to uncertainty about the weather; (3) the lack of certainty about behavior of the never- used Emergency Spillway, with unstable terrain; and (4) the risk of misunderstanding or misinterpreting model results as critical decisions were made. Solutions included: (1) the use of cloud computing, with parallel model runs on multiple servers in the Amazon cloud; (2) analysis with ensemble forecasts, coupled with sensitivity analysis with varying inflow hydrograph properties; (3) constant monitoring and reporting to modelers of observed changes to the spillways so model inputs could be adjusted; and (4) careful communication of results by DWR and consultant experts. KEY WORDS ANALYSIS, APPURTANANT STRUCTURE, BEHAVIOR, CAVITATION, CHUTE, CONCRETE DAM, CONSTRUCTION, CREST, DAM, DAM OPERATION, DAMAGE, DESIGN, DISCHARGE, ENERGY DISSIPATOR, FAILURE, FLOOD CONTROL, FLOW, FCO SPILLWAY, GAUGE, GEOLOGICAL INVESTIGATION, HYDRAULIC MODEL, HYDROLOGY, MAIN SPILLWAY, MATHEMATICAL MODEL, NUMERICAL MODEL, MODEL, OPEN CHANNEL, OPERATION, OUTLET DISCHARGE, OUTLET STRUCTURE, PERFORMANCE, PHYSICAL MODEL, PLUNGE POOL, POPULATED AREA, POPULATION DISPLACEMENT, PROTECTIVE MEASURES, REGULATION, REPAIR, RESERVOIR, RESERVOIR OPERATION, RUNOFF, SAFETY, SIDE SPILLWAY, SLOPE STABILITY, SPILLWAY 143