Post on 18-Jul-2020
IS TUCSON SINKING?
Arizona Department of WaterResources
National Monitoring DayOctober 18, 2002
IS TUCSON SINKING?
IS TUCSON SINKING?
IS TUCSON SINKING?
IS TUCSON SINKING?
IS TUCSON SINKING?
IS TUCSON SINKING?
IS TUCSON SINKING?
LandLandSubsidence Subsidence
Measurement Measurement Using Using
SAR SAR InterferometryInterferometry
ADWR10/2002
What Is SAR Interferometry?
Land Surface
SequentialSatellitePasses
Radar Interferogram 6/1993 to 1/1996
-0.8 in./yr. Max
Air Forcebase
5th St. & Country Club
Downtown
University
Irvington & Park Ave.
Radar Interferogram 11/1993 to 1/2000
-0.8 in./yr. Max
Air Forcebase
5th St. & Country Club
Downtown
University
Irvington & Park Ave.
What Causes Subsidence?
SandsSands ClaysClays
H2OH2O
What Causes Subsidence?
Sands Clays
What Causes Subsidence?
Sands Clays
Over-Burden
Over-Burden
Techniques for Measuring Land Subsidence
• Global Positioning System (GPS) Surveys– Point measurement– Accurate within 1 inch
• Extensometers (measuring sticks in wells)– Point measurement– Very accurate, but only measures part of
aquifer
• SAR Interferometry– Large-scale measurement
– New, requires “ground-truthing”
• Subsidence on the order of INCHES rather than FEET– Eloy, over 15 feet of subsidence by 1980s– Luke Air Force Base, over 10 feet of
subsidence by 1990s
• Subsidence in Tucson is REAL!– Potential damage to infrastructure
– No confirmed effects yet in Tucson
What Does It Mean?
Photo: H.H. Schumann
ELOY, AZ
What Can We Do?
• Use Renewable Supplies
• Conserve Water!
• Continue to Monitor
Arizona Department of WaterResources• http://www.water.az.gov
SPECIAL THANKS TO:
• Center for Space Research, University of Texas– Dr. Sean Buckley
• ADWR Staff– Maurice Tatlow
• California Institute of Technology– Dr. Jakob van Zyl