Sensor Information
*Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. government.
Data Acquisition System
Sensors at the site are read with two Campbell Scientific, Inc., CR10X dataloggers and peripheral devices powered by battery and solar panels. The dataloggers are equipped with digital cellular modems for dial-up data acquisition. The sensors are currently read every 15 minutes, with the data collected daily by a USGS computer in Golden, Colorado. Data are sometimes downloaded more frequently by user initiated dial-up to the dataloggers.
Precipitation Gauge
Rainfall Chart | Rainfall DataThe site is equipped with one 8-inch-diameter tipping bucket rain gauge that is calibrated to 0.01 inch (0.254 mm) of rainfall per tip.
Piezometers (ground water pressure sensors)
In 2003, the site was equipped with three vibrating-wire piezometers installed in sand packs just above the basal slip surface of the landslide. In late 2006, 12 additional piezometers were installed at various depths in two boreholes near the locations of the original piezometer installations. These piezometers were installed using the grout-in method, wherein the piezometers are embedded in a bentonite-Portland cement column in the borehole. Two additional standpipe piezometers, one each in two boreholes, were installed in sand packs to monitor water levels and for possible future hydrologic testing at the site. Because groundwater pressures near the basal slip surface are the most critical with respect to landslide movement, only the data from the three piezometers near the base of the slide are reported in this web site. Groundwater pressures are reported as pressure head, in meters of water. The piezometers (Slope Indicator, Inc. model 52611020) have a pressure range of 0-35 m of water, a resolution of ±0.025% full scale, and accuracy of ±0.1%. The piezometer data displayed on this site have been compensated for temperature, but have not been adjusted for barometric pressure variations.
Extensometers (movement sensors)
In 2004, cable-extension transducers were installed and attached to downhole extension cables originally installed in three borehole in 2003. Landslide movement overrides the downhole cable at the basal slip zone, pulling the cable into the borehole an amount approximately equal to the slide movement. The cable-extension transducers attached to the cable convert this movement to an electrical signal read by the datalogger. The electric signal is converted to centimeters of movement by the datalogger. The cable-extension transducers (Celesco, Inc., model PT8101) have a range of 0-152 cm, with a stated accuracy of ±0.10% full range. Resolution of movement is approximately 0.5mm with the Campbell Scientific, Inc. CR10x datalogger used to record the data.
Other Sensors
Other sensors deployed at the site but not currently included in this web site report are an air-temperature sensor, four shallow soil-moisture sensors, and a vibrating-wire piezometer used to record barometric pressure variations.
