Post-Earthquake Restoration of the Los Angeles Water Supply System

Keywords: Post-earthquake restoration.  Los Angeles Department of Water and Power (LADWP).  Water supply systems.  Discrete event simulation models.  Lifelines.  Restoration models.  Data analyses.  Northridge, California earthquake, January 17, 1994.  Public policy.  Damage.  Distribution.  Inspections.  Repairs.

Abstract: The purpose of this report is to develop a discrete event simulation model of post-earthquake restoration for the Los Angeles Department of Water and Power (LADWP) water supply system.  The utility company’s decision variables are included explicitly, allowing exploration of their effects on the speed of the restoration.  Restoration times are estimated separately for each region within the service area, and uncertainty in the process is modeled explicitly.  Extensive review of the LADWP water organization, water supply system, and post-earthquake restoration process was conducted.  The restoration model provides several different types of output including system and subregion restoration curves; spatial distribution of restoration; material usage; crew usage; average time each customer is without water; and time to restore the system and subregions to 90 (percent), 98 (percent), and 100 (percent).  Ten simulations of the restoration model were run using real damage data from the 1994 Northridge earthquake as input, and the results were compared to the actual restoration that took place following Northridge.