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Monitoring location 159 S08 E52 27 4 U -12j Ext. Tunnel - USGS-371313116094001

Important for you to know:

  • USGS will be performing maintenance on WDFN webpages beginning Tuesday, May 12. If you cannot access the page you are intending or are unexpectedly redirected to a different page, please reach out to wdfn@usgs.gov for assistance.