Profile Resolving In-Situ Soil Moisture Sensor
The ability to acquire time series measurements of in-situ soil moisture in continuous profile has long been desired in numerous applications...
from waste site remediation monitoring to dam and levee health surveillance, early warning of landslide potential to improved irrigation management, as well as monitoring of land-atmosphere interactions for input to climate models.
Transcend Engineering has invented a sensing technology called PRISMS, for "Profile Resolving In-Situ Soil Moisture Sensor," that provides long-term time series monitoring of spatially resolved profiles of soil water content in the unsaturated zone.
PRISMS combines advances in the processing of TDR data with innovations in the physical sensing apparatus. These advancements enable high temporal (and thus spatial) resolution of reflectance continuously along the inside surface of a borehole using a waveguide that is permanently emplaced in contact with the adjacent soils.
PRISMS is in use by pioneering researchers investigating the role of soil moisture dynamics in important terrestrial processes. Development of PRISMS has been supported through funding from the US Department of Energy's Office of Science through a Small Business Innovation Research (SBIR) grant.
HOW PRISMS WORKS
PRISMS uses the principle of Time Domain Reflectometry (TDR) to measures soil water content. Conventional TDR probes only provide a single measurement of an average volume. Unlike conventional TDR, PRISMS provides detailed profiles of water content along waveguides up to two meters in length.