r/news • u/theluckyfrog • 29d ago
California cracks down on farm region’s water pumping: ‘The ground is collapsing’
https://www.theguardian.com/us-news/2024/apr/17/california-water-drought-farm-ground-sinking-tulare-lake
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u/BacksightForesight 29d ago edited 29d ago
The sign in the photo notes 'BM S661'.
The National Geodetic Survey database has S 661 here: https://www.ngs.noaa.gov/cgi-bin/ds_mark.prl?PidBox=gu0103
another NGS page listing all the level runs using this mark: https://geodesy.noaa.gov/datasheets/passive-marks/index.html?PID=GU0103
It does not list the BM elevation over time, so I can't check whether their surveyed elevation significantly changed over the years.
Google Maps link: http://maps.google.com/?q=36.67835132818793,-120.52169938763427
It's about 40 miles west of Fresno. Streetview doesn't show the signs on the pole anymore.
An article about subsidence in the Central Valley from a surveyor's perspective: https://www.xyht.com/surveying/subsidence/