Seite - 81 - in Book of Full Papers - Symposium Hydro Engineering

 Faiz Makdisi, Ph.D., P.E., D.GE  Paul Schweiger, P.E., P.Eng, CFM The Board of Consultants held their first meeting on March 1-3, 2017, with the Spillway Recovery Team and dam safety regulators. Between March and December 2017, the Board of Consultants met 14 times to review the designs and to inspect construction in the field. The Board of Consultants completed written reports following each meeting, providing comments and recommendations to the Spillway Recovery Team, DSOD, and FERC, which DWR then made available to the media and the general public. OER also participated in a Risk Assessment Workshop conducted by the United States Army Corps of Engineers in April 2017 and in a Potential Failure Mode Analysis workshop in May 2017 conducted by DWR. These two workshops focused on the safety of the FCO Spillway chute and the Emergency Spillway. 5. LAKE OROVILLE OPERATIONS Following the 2017 incident, DWR used the damaged FCO Spillway chute intermittently between February and May 19, 2017, to pass reservoir inflows to avoid using the unreliable Emergency Spillway. On May 12, DWR completed a Near-Term Lake Oroville Operations Plan to support the final 2017 closure of the spillway (FCO) gates in the second half of May, and to use the Hyatt Powerplant releases to lower the reservoir to Elevation 214 m (700 ft) by November 1, 2017. The objective of this operations plan was to minimize the likelihood of using either spillway during the rest of the 2017 construction season, and to also minimize the need for using the Emergency Spillway at all during the 2017-2018 Winter Flood Season. On October 16, 2017, DWR completed a Lake Oroville 2017/2018 Flood Control Season Operations Plan targeted to limit flows on the FCO Spillway chute and to prevent any flow through the Emergency Spillway. The 2017/2018 Plan was based on hydrologic and hydraulic analyses using historical precipitation, snowpack, and reservoir data. It was also developed to balance the competing needs of dam safety versus downstream flood safety. The 2017/2018 Plan incorporates a low initial reservoir elevation target to be held during the Winter Flood Season and uses reservoir set points where increasing releases would be made from the Hyatt Powerplant and the FCO Spillway chute to avoid the use of the Emergency Spillway. The 2017/2018 Plan allows the reservoir to pass the Standard Project Flood without releases on the Emergency Spillway and without a discharge greater than 2800 m3/s (100,000 ft3/s) on the FCO Spillway chute. 81