Page - 126 - in Book of Full Papers - Symposium Hydro Engineering

during the incident and later as part of the recovery; (b) hydrologic, hydraulic, and operation analysis models and methods used for the analyses; (c) strategies for development, review, and coordinated use of the models and methods by a large team of analysts; and (d) problems faced and solutions found as the models were configured, calibrated, and applied to provide information to design staff and influence interim operation decisions required throughout the response and recovery efforts. 2. PROJECT FEATURES AND HISTORICAL PERFORMANCE The original design of Oroville Dam, including selection of types and capacities of spillways and placement of the Flood Control Outlet (FCO) Spillway chute and Emergency Spillway relative to the embankment, and the details of a tightly-integrated operation policy, were the result of more than thirteen years of hydrologic and hydraulic (H&H) engineering and operation studies. An initial design and operation policy was proposed in 1953 and refined in 1955 with results from a scaled physical-model study [2]. To accommodate updated operational requirements by the United States Army Corps of Engineers (USACE), the 1955 design was revised in 1958 and again in 1962. A physical modeling study of the revised spillway concept was carried out in 1962 by the United States Bureau of Reclamation (USBR). To address issues identified then, the FCO Spillway chute and the Emergency Spillway were configured as two separate structures [3]. The Oroville Project consists of the main dam, two saddle dams, a flood control outlet structure, an emergency spillway with concrete weir upstream of an unlined hill slope, and a hydropower plant. 126