Results of Hydrologic Monitoring of a Landslide-Prone Hillslope in Portland's West Hills, Oregon, 2006-2017

The West Hills of Portland, in the southern Tualatin Mountains, trend northwest along the west side of Portland, Oregon. These silt-mantled mountains receive significant wet-season precipitation and are prone to sliding during wet conditions, occasionally resulting in significant property damage or casualties. In an effort to develop a baseline for interpretive analysis of the groundwater response to rainfall, an automated monitoring system was installed in 2006 to measure rainfall, pore-water pressure, soil suction, soil-water potential, and volumetric water content at 15-minute intervals. The data show a cyclical pattern of groundwater and moisture content levelswet from October to May and dry between June and September. Saturated soil conditions tend to last throughout the wet season. This release presents data collected from January 10, 2006, through January 23,2017. Three files are included with this release. Two comma separated value (csv) files contain monitoring data for the time-periods described by their file name, for example 20061106_20170123.csv contains data for the period between November 11, 2006 and January 23, 2017. A read-me file (readme.docx) describes the sensor naming convention used for column names in the data files.