Subsidence at Conaway Ranch, Yolo County Tad Bedegrew October 29, 2015 North Central Region Office - DIRWM Geology and Groundwater Investigations Section
Presentation Outline Background Information Construction Info Period of Record Recent Activity Future Plans Continuous recording/CDEC 2
Location 3 Davis Woodland West Sacramento Yolo County Sacramento County
Construction Information
Extended Period of Record 5
2013 Water Transfer 6 20 Pumping Wells ~5,700 AF Pumped for Transfer July – September
2013 Displacement 7
2014 Water Transfer 8 22 Pumping Wells ~14,000 AF Pumped for Transfer May – early September
2014 Displacement 9
2014 Survey 10 Extensometer Survey showed ~6” of subsidence at Extensometer location
2014 Survey Comparison 11
2014 Extensometer Modifications 12 ~2” May 27, 2014
2014 Extensometer Modifications 13 5/27/14 6/16/14 7/8/14 8/7/14 ~1” ~2” ~4”
2014 Extensometer Modifications Round 2 14 ~4” August 12, 2014
Slip Joint seized up? Subsidence occurring between 620’ and the surface? Combination of the two? Why?
2015 Water Transfer Pumping Wells ~5,400 AF Pumped for Transfer Late May - June
2015 Displacement 17
Current Recording Equipment years old No longer continuous recording, must move pin manually Visiting Conaway Extensometer weekly since May 2014 due to activity
Future Plans 19 Installation of digital shaft encoder Continuous recording using CR1000 Data Logger Cellular Telemetry CDEC?
NASA JPL InSAR 20
Questions? 21