U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 11/20/1990
Station ID: 8720767 SUPERCEDED DATE: 04/21/2003
Name: BUFFALO BLUFF, ST JOHNS RIVER
FLORIDA
NOAA Chart: 11492 Latitude: 29° 35.7' N
USGS Quad: PALATKA Longitude: 81° 40.9' W
To reach the tidal bench marks from the junction of County Road C-309 and U.S.
Highway 17 in Satsuma, proceed north on U.S. Highway 17 for 0.95 mile (1.53 km)
to County Road C-309B (Buffalo Bluff Road), then NW on County Road C-309B for
2.0 miles (3.2 km) to a private driveway leading NE across the railroad tracks,
cross the tracks and continue NE on the track road parallel to the railroad
tracks for 0.6 mile (1.0 km) to the railroad bridge. The bench marks are on the
railroad bridge and nearby. The tide gage and staff were below the bridge span.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 0767 B 1978
MONUMENTATION: Survey Disk VM#: 5249
AGENCY: PID#: AQ2567
SETTING CLASSIFICATION: Concrete Bridge Pier Foundation
The bench mark is set flush in the SW corner of the concrete pier foundation at
the south end of the bridge drawspan, 275 feet (84 m) north of Bench Mark 0767 A
1978, 38 feet (12 m) west of the drawbridge control house at the center of the
bridge, 5.0 feet (1.5 m) north of the south edge of the pier foundation, and 4.8
feet (1.5 m) below the level of the railroad tracks.
BENCH MARK STAMPING: 0767 A 1978
MONUMENTATION: Survey Disk VM#: 5248
AGENCY: PID#: AQ2566
SETTING CLASSIFICATION: Concrete Wingwall
The bench mark is set flush in the concrete wingwall at the SW corner of the
bridge, 143.6 feet (43.8 m) NW of the NW corner of the bridge tender's
residence, 20 feet (6.1 m) NW of the south shoreline, 18 feet (5 m) SW of the
centerline of the railroad tracks, and 8.9 feet (2.7 m) west of the handrail
along the west side of the bridge.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 11/20/1990
Station ID: 8720767 SUPERCEDED DATE: 04/21/2003
Name: BUFFALO BLUFF, ST JOHNS RIVER
FLORIDA
NOAA Chart: 11492 Latitude: 29° 35.7' N
USGS Quad: PALATKA Longitude: 81° 40.9' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0767 C 1978
MONUMENTATION: Survey Disk VM#: 5250
AGENCY: PID#: AQ2568
SETTING CLASSIFICATION: Concrete Wingwall
The bench mark is set flush in the concrete wingwall at the NW corner of the
bridge, 610 feet (186 m) NNW of Bench Mark 0767 B 1978, 25 feet (8 m) south of a
telephone box at the NW corner of the bridge, 11.5 feet (3.5 m) west of the
centerline of the railroad tracks, and level with the bridge surface.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 11/20/1990
Station ID: 8720767 SUPERCEDED DATE: 04/21/2003
Name: BUFFALO BLUFF, ST JOHNS RIVER
FLORIDA
NOAA Chart: 11492 Latitude: 29° 35.7' N
USGS Quad: PALATKA Longitude: 81° 40.9' W
T I D A L D A T U M S
Tidal datums at BUFFALO BLUFF, ST JOHNS RIVER based on:
LENGTH OF SERIES: 5 MONTHS
TIME PERIOD: NOVEMBER 1978-APRIL 1979
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8720220 MAYPORT
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (10/31/1978) = 2.20
MEAN HIGHER HIGH WATER MHHW = 1.03
MEAN HIGH WATER MHW = 0.99
MEAN TIDE LEVEL MTL = 0.52
MEAN LOW WATER MLW = 0.06
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (01/26/1979) = -1.16
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
0767 B 1978 5.79 4.80
0767 A 1978 11.01 10.02
0767 C 1978 10.79 9.80
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 11/20/1990
Station ID: 8720767 SUPERCEDED DATE: 04/21/2003
Name: BUFFALO BLUFF, ST JOHNS RIVER
FLORIDA
NOAA Chart: 11492 Latitude: 29° 35.7' N
USGS Quad: PALATKA Longitude: 81° 40.9' W
D E F I N I T I O N S
Mean Sea Level (MSL) is a tidal datum determined over a 19-year National Tidal
Datum Epoch. It pertains to local mean sea level and should not be confused
with the fixed datums of North American Vertical Datum of 1988 (NAVD88).
NAVD88 is a fixed datum derived from a simultaneous, least squares, minimum
constraint adjustment of Canadian/Mexican/United States leveling observations.
Local mean sea level observed at Father Point/Rimouski, Canada was held fixed as
the single initial constraint. NAVD88 replaces NGVD29 as the national
standard geodetic reference for heights. Bench mark elevations relative to
NAVD88 are available from NGS through the World Wide Web at
National Geodetic Survey.
NGVD29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded. NGVD29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads. NGVD29 was originally derived from a general
adjustment of the first-order leveling networks of the U.S. and Canada after
holding mean sea level observed at 26 long term tide stations as fixed.
Numerous local and wide-spread adjustments have been made since establishment in
1929. Bench mark elevations relative to NGVD29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at
National Geodetic Survey.
NAVD88 and NGVD29 are fixed geodetic datums whose elevation relationships to
local MSL and other tidal datums may not be consistent from one location to
another.
The Vertical Mark Number (VM#) and PID# shown on the bench mark sheet are unique
identifiers for bench marks in the tidal and geodetic databases, respectively.
Each bench mark in either database has a single, unique VM# and/or PID# assigned.
Where both VM# and PID# are indicated, both tidal and geodetic elevations are
available for the bench mark listed.
The NAVD88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD88 elevations.
The NAVD88 elevation relationship shown in the table is derived from an average
of several bench mark elevations relative to tide station datum. As a result of
this averaging, NAVD88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD88 elevations listed for
each bench mark in the NGS database.