Teton Dam and South Fork Dam: Validating the Life Loss Methodology in LifeSim through Case Studies on Large Dams

The U.S. Army Corps of Engineers (USACE) has developed methodology to estimate potential life loss from flooding, which is built into the software program LifeSim. Life loss estimates from LifeSim are a component of the risk assessment process used by USACE in its Dam and Levee Safety programs to estimate infrastructure risk and make decisions on managing that risk at the portfolio level. Validation studies provide a measure of confidence and improved understanding of the potential uncertainties in life loss modeling.
LifeSim estimates the redistribution of population in response to a flood using various warning and mobilization curves. To determine the percentage of population at risk (PAR) within an area that is warned and mobilized over time, several parameters are used within LifeSim to estimate the probable values of warning and mobilization percentages at each time step. These parameters include when hazards are identified and warnings will be issued (hazard identification and delays), how long it will take for the warning to become effective (warning diffusion), and the rate at which PAR will mobilize in response (mobilization). These parameters were adjusted in two ways: (1) validating the software by fine-tuning input parameters to match the events that occurred and (2) validating standardized USACE processes by utilizing built-in or preset LifeSim parameters based on case history research.(Continued)