Estimating Landslide Losses to State Highways: a General Approach for a Winter Storm Scenario

ARkStorm is a statewide emergency planning scenario hypothesizing severe storms that entrain huge amounts of moisture from the tropical Pacific and dump it on California over a few days. The storm is projected to be similar to but more intense than storms that have struck California in recent decades, and approach the massive storms of 1861-1862 in total rainfall. Estimating the numbers and impact of landslides from the ARkStorm requires models relating rainfall to the numbers and distribution of landslides and detailed records of the impact of landslides in past storms. Neither of these basic data sets exist. Models that estimate the areas with the greatest susceptibility to landsliding do exist, however. These can be combined with records of landslide damage and areas likely to be damaged and total damage can be projected. Quality of the projection depends on the amount of data. This study is based on landslide damage data developed by Caltrans over the past ten years. This data is enough to develop a general method for estimating landslide damage but not sufficient to give us confidence in the results. The general pattern of statewide landslide susceptibility is similar to the pattern of landslide damage to state highways, as recorded by Caltrans emergency opening and SHOPP repair projects. The amount of damage is correlated with the total statewide annual rainfall. Emergency opening costs are higher in years of greater than average rainfall. SHOPP landslide repair costs show a similar pattern, but lag a year or two behind the rainfall. The authors have extrapolated the incomplete records of damage from landslides in past storms to the ARkStorm. Projecting damage estimates from a short data set leads to significant uncertainty in the result. Using the highest recorded intensity estimates, damage to infrastructure due to landslides triggered by ARkStorm could approach two billion dollars.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; References;
  • Pagination: pp 334-343
  • Monograph Title: Proceedings of the 63rd Annual Highway Geology Symposium (HGS 2012)

Subject/Index Terms

Filing Info

  • Accession Number: 01661552
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 25 2018 10:51PM