Data Collection Activities

This chapter discusses the data collected and used to assess the failure at Rat Creek. For the analyses conducted, the reconnaissance team used a variety of datasets to develop the figures and quantities presented in this chapter. The pre-failure LiDAR and derived 3.3 ft (1 m) bare-earth DEM used herein were sourced from the USGS West Coast El Nino LiDAR Project Area using the USGS 3DEP LiDAR Explorer. Following coordination with Caltrans, a field reconnaissance was conducted by the investigation team at the Rat Creek Highway 1 crossing on February 25, 2021. Field reconnaissance involved observations at the construction site, upstream reaches of Rat Creek, terrestrial LiDAR scans, acquisition of low-altitude UAV imagery, and cleaning, logging, and sampling of a terrace exposure within Rat Creek. Planet 4-band satellite imagery at 3 m resolution was used in the analyses presented.