New Measuring Standard Will Improve Accuracy of Water Level Data
SFWMD Upgrading from NGVD 29 to NAVD 88 - Vertical Datum Upgrade
To enhance the accuracy of our data, the SFWMD is upgrading the reference system used to measure water elevations in our monitoring network. In the coming months, SFWMD will shift from reporting water elevations in the National Geodetic Vertical Datum of 1929 (NGVD 29) to the North American Vertical Datum of 1988 (NAVD 88). This includes data within the SFWMD’s environmental database for hydrologic, meteorologic, hydrogeologic and water quality data.
The upgrade will provide the public and stakeholders more accurate information about levels for waterbodies in our region.
Depending on the location within the SFWMD, water levels in the newer NAVD 88 measurement system will be approximately 0.6 feet to 1.6 feet lower than they are in the older NGVD 29 measurement system.
For example, the difference between the two measuring standards in Lake Okeechobee is 1.25 feet, so a water level of 11.25 feet NAVD 88 is 12.5 feet NGVD 29.
Water elevations are reported as the height of the water surface compared to sea level.
Water depth on the other hand, is the height of the water surface as measured from the bottom of the water body.
When NAVD 88 is fully implemented in 2024, water measurements will be published exclusively in NAVD 88.
FAQ’s – Upgrading from NGVD29 to NAVD88
Fact Sheet – Improving Accuracy of Water Level Data
Stay tuned to this webpage for updates about the upgrade and sign-up for updates below.