Water Table Depth
OC Sensor
Description
An "OC" sensor allows automated measurement of the level of the water table at a particular location. Data is collected every 12 hours. The Water Table Pressure (OC) sensor consists of a pressure transducer placed near the bottom of a 15-foot deep PVC pipe, drilled with holes to allow the water table level to stabilize within it. Higher pressure readings equate to water table levels closer to the surface of the pavement.
Manufacturer
Campbell Scientific CS425- Druck PDCR 1830-8389.
Location and Quantity
OC sensors have been installed in several test cells.
Current Status
Some "OC" sensors continue to function.
MnROAD Database Table
OC data can be found in MnROAD database tables: MNR.OC_COAX_RAW_VALUES, OC_TRANS_RAW_VALUES.
Open Stand Pipe - OS
Description
An "OS" sensor allows measurement of the level of the water table at a particular location. Data for the original installations was collected manually at various times. More recent installations are automated with an "OC" sensor and collected once every 12 hours. The Open Standpipe (OS) sensor consists of a 15-foot deep PVC pipe, drilled with holes to allow the water table level to stabilize within it. Originally, measurements were obtained by lowering a water-sensing probe into the pipe. More recent installations have included automated pressure "OC" transducers inserted into the bottom of the tube. See the "OC" description for more details.
Manufacturer
OS are fabricated by MnROAD staff.
Location and Quantity
OS sensors were originally placed 25 feet from the roadway centerline (just beyond the shoulder). More recent installations have included an OS sensor underneath the centerline of the roadway.
There was originally one OS sensor installed in each of the 40 MnROAD test cells. Newer test cells have added additional OS sensors.
Current Status
Manual readings of the OS sensors ceased after March 2002. Some newer test cells have "OC" sensors installed to automate the measurements.
MnROAD Database Table
Manual OS data can be found in MnROAD database table: MNR.OS_MANUAL_VALUES.