1. AEG Annual Meeting-Boston
Mitigation Design of Geohazards Caused
by Fire at Hydroelectric Facilities
• W.H. Godwin, CEG William Lettis & Associates
• Don Quigley, GE MACTEC Engineering & Consulting, Inc.
• C. Liu, PE, SFPUC Engineering & Design Bureau
November 1, 2006
2. Introduction
• Purpose
• Case Study
– Early Fire
– Damage Assessment
– Aerial and Field Mapping
– Mitigation Design
– Construction
• Acknowledgements and Questions
6. Early Fire
• Life & Property
–CCSF Life & Property
–Public Life & Property
• Soil & Water Quality
• Special Areas
-Wild and Scenic River
-Heritage Oaks
8. Early Fire
• Conceptual Treatments for:
-Powerhouse
-Residences
-Roads
-Penstock
-Transmission Lines
• Detailed engineering assessment of drainage
and structure protection by SFPUC
30. Mitigation Design
• Design outputs for 11 fences
• Energy ranges from 241kJ to 1575kJ
• Bounce height (90%) range 3 ft to 24ft
• Did not factor in trees as barriers
• Fence Heights of 2 to 4 meters
31. Mitigation Design
Hydrologic Analysis
• 25 year return interval, 24-hour hydrologic
analysis for both pre- and post-fire conditions
• 100 year return interval, 24-hour duration
hydrologic analysis for both pre- and post-fire
conditions
• Calculation of parameters used in the HEC-1
model followed the NRCS methodology.
37. Construction
December-May 2005
• Rock fencing (3131LF)
• Draped mesh, spot bolting
• New access road and culverts
• Hardened Crossings
• Penstock drains and safety lines
• New potable water tanks
