Meeting Notes:
12/8/06

Dan Gilleland of the Santa Clara Valley Water District gave a talk on how his organization set up a GPS network to monitor the 10 earthern dams in Santa Clara County. The Division of Safety of Dams requires that the Water District check for movement of the dams annually. The District checks all dams annually and some quarterly.

The issue is repeatability. Some problems are: spikes in trees move over time, control gets destroyed due to construction, land subsidence and slides and the fault lines that run through the county.

The solution was to do a GPS survey. In 1994 the District did a GPS survey for a control network and developed coordinates in 1991.35 HPGN.
The District filed a Record of Survey in Book 781 at pages 1-5 with an epoch of 2004.082. They expect to update their survey in 2007.

The trend is to move to a reservoir surveillance program using a remote automated system where robotic instruments and continuously operating reference stations (CGPS) monitor the dams and send the information to a central location. Cecilia Whitaker of the Metropolitan Water District in Southern California currently has such a system where she can monitor dams from over a hundred miles away.

Jim Swanson of the East Bay Regional Park District gave an update of the East Bay GPS Network. Currently the Park District is working with UC Berkeley Seismological Lab and UNAVCO to set up a server to transmit 1 second single baseline RTCM free over the internet hosted by UC Berkeley.
This system is designed to be off the power and telephone networks and to continue monitoring earth movements during an earthquake. Solar powered GPS receivers and radios will transmit RTCM to UC Berkeley, which has an extensive electrical backup system, allowing data collection during earthquakes.

Brett Baker and Duncan Marshall were reelected as President and Secretary of the NCGPSUG


Respectfully submitted,
Duncan Marshall
Secretary

Here is a note from Marti.