Advances in Tensiometry for Long-Term Monitoring of Soil Water Pressures

Journal Article · Mon Jul 01 04:00:00 UTC 2002 · Vadose Zone Journal

OSTI ID:912164

Singler, Robert Edward; Hubbell, Joel Michael; Gee, G W; Ritter, J C; Ward, A L; Bratton, W L; Caldwell, T G

Soil water pressures, measured over space and time, are needed to predict the direction of water flow and chemical transport in the vadose zone. Advanced tensiometers (ATs), which utilize a water-filled porous cup connected directly to a pressure transducer, can be installed at almost any location and depth using standard drilling techniques such as auger drilling, but these methods can significantly disturb the site. For sites where minimal disturbance is desired, alternate approaches for tensiometer placement have been sought. To test installation techniques and performance longevity, advanced tensiometers were placed into the ground at a test site near Richland, WA using two different installation methods, auger drilling and a drive-cone push technique. The tensiometers were subsequently monitored for nearly 2 yr without refilling or recalibration. The data indicated that tensiometers placed by the auger technique took several months to equilibrate, while the cone push units came to equilibrium within 24 h following their installation. Soil water pressures always remained above -90 cm pressure head (-90 mbar) at depths >90 cm. At the greatest depth (730 cm), positive then negative pressures were observed as the water table was lowered and the soil drained. The results suggest that for our test conditions (coarse sandy soil, no vegetation), soil water pressures stay well within the tensiometer range and unit gradient conditions persist, indicating a draining profile. Advanced tensiometers, placed either by auger or cone penetrometer, provide a robust and reliable method for long-term monitoring of soil water pressure profiles

• Research Organization: Idaho National Laboratory (INL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC07-99ID13727
• OSTI ID: 912164
• Report Number(s): INEEL/JOU-02-01190
• Journal Information: Vadose Zone Journal, Journal Name: Vadose Zone Journal Vol. 1
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
CONES
DISTURBANCES
DRILLING
MONITORING
PERFORMANCE
PLANTS
SOILS
TRANSPORT
WATER
WATER TABLES
auger drilling
drive-cone push
soil water pressures
tensiometry
vadose zone
water flow