NWDTW 2024

The California Water Science Center’s Estuarine Hydrodynamics team works in the Sacramento-San Joaquin River Delta (the Delta) and faces two main challenges with tying water level to datum. Challenges include: 1) long distances between land and gage infrastructure on pilings in the river (sometimes ~300m+). This makes it virtually impossible to use traditional leveling techniques. 2) land movement. The Delta is comprised of human-made levee systems that are susceptible to significant movement due to the organic soils of the region. Couple this with the movement of a given gage’s piling and it becomes extremely time consuming and costly to determine the accuracy of the water level’s data tied to datum.
The solution? Automate static GNSS surveys on every gage every week. We use a single board computer (SBC), GNSS Survey Grade Receiver, cellular modem, and datalogger to conduct a 12-hour static survey once per week. Once the survey is complete, the SBC packages the raw data, converts those data to a format the National Geodetic Survey’s Online Position User Service (OPUS) can ingest and then sends the converted file off to the USGS sFTP server as well as OPUS. Once the OPUS corrections have been made, we receive an email containing the corrected data and metadata and can then relate those data to our water level with much more confidence.