SWATS Status, EF 30s Progress, and Potential Changes

Description

Several of the original SWATS systems have been in use for nearly two decades, whereas new installations at the Extended Facilities in the 30s (EF30s) were installed about four years ago. Some of the original SWATS systems have experienced sensor or electronics failures, which is not uncommon for the sensors being used. Several of the sensors were replaced in the EF13 (Central Facility) system in 2006. The EF30s systems are awaiting the completion of the ingest process; the raw data from those newer systems has been collected and archived for a few years now. A recent comparison study of several manufacturer's soil moisture sensors performed by Oklahoma State University indicates that the sensor used in the SWATS (Campbell Scientific CS299L Matric Potential Sensor) exhibits the poorest response to the range of soil moisture encountered in the study, but had a relatively low failure rate over thee years. The SGP SWATS seem to show more sensitivity than the 299L sensors in the study. It seems prudent to update the SWATS sensors to the more sensitive Stevens Water Hydra Probe or the Delta-T Theta Probe; these probes would first be installed at two new SGP Extended Facilities presently in the planning stage and possibly alongside the present SWATS at the Central Facility, to allow a comparison.