U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8729119 PUBLICATION DATE: 11/13/2003
Name: SHELL ISLAND, ST. ANDREW B.
FL
NOAA Chart: 11391 Latitude: 30° 5.7' N ( 30.09500)
USGS Quad: BEACON BEACH Longitude: 85° 41.1' W ( -85.68500)
To reach the tidal bench marks from the boat launch at St. Andrew State Park,
proceed SSE 6.3 km (3.9 mi) to about midpoint, on the NE shoreline and Captain
Andersons Shell Island Tours Pier on Shell Island. The bench marks are located
along and the grassy sand dunes along the middle of Shell Island between St.
Andrew Bay and the Gulf of Mexico on a NW-SE line from the pier, and the gage
site and staff were located on the pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 3 1976
DESIGNATION: 872 9119 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 10013
AGENCY: National Ocean Survey (NOS) IDB PID#: BE1354
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 30° 5.7' N ( 30.09500) LONGITUDE: 85° 41.1' W ( -85.68500)
The primary bench mark is a disk located on the SE edge of the low ground
between two ridges of grassy covered sand dunes, 1.58 m (5.2 ft) NW of a line of
three 3 m (10 ft) high piles, and 12 cm (0.4 ft) NNW of a witness post. The
bench mark is set 6 cm (0.2 ft) below ground level, crimped to the top of a
copper-clad steel rod driven 12 m (40 ft) to refusal, and encased in a PVC pipe
and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8729119 PUBLICATION DATE: 11/13/2003
Name: SHELL ISLAND, ST. ANDREW B.
FL
NOAA Chart: 11391 Latitude: 30° 5.7' N ( 30.09500)
USGS Quad: BEACON BEACH Longitude: 85° 41.1' W ( -85.68500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: R114 BAY CO 1972
DESIGNATION: R 114 FLDNR
MONUMENTATION: Survey disk VM#: 10014
AGENCY: Florida Department of Natural Resources
(FLDNR) IDB PID#: BE1353
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 30° 5.6' N ( 30.09330) LONGITUDE: 85° 41.1' W ( -85.68500)
The bench mark is a disk set into the top of a concrete monument on the grassy
ridge of sand dunes paralleling the bay, 183 m (600 ft) SSW of the bay, 177 m
(580 ft) NW of bench mark NO 3 1976, 107 m (350 ft) NNE of the Gulf of Mexico,
19.48 m (63.9 ft) NE of the NE corner of the beige cottage on the beach, and
6.37 m (20.9 ft) south of a water pump.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8729119 PUBLICATION DATE: 11/13/2003
Name: SHELL ISLAND, ST. ANDREW B.
FL
NOAA Chart: 11391 Latitude: 30° 5.7' N ( 30.09500)
USGS Quad: BEACON BEACH Longitude: 85° 41.1' W ( -85.68500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: R115 BAY CO 1972
DESIGNATION: R 115 FLDNR
MONUMENTATION: Survey disk VM#: 10015
AGENCY: Florida Department of Natural Resources
(FLDNR) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 30° 5.6' N ( 30.09330) LONGITUDE: 85° 41.1' W ( -85.68500)
The bench mark is a disk set into the top of a concrete monument on a grassy
ridge of sand dunes paralleling the bay, 0.9 km (0.6 mi) ESE of bench mark R114
BAY CO 1972, 155 m (510 ft) SE of the SE inner corner of the pier on the bay,
149 m (490 ft) south of bench mark NO 1 1976, and 76.20 m (250.0 ft) north of
the Gulf of Mexico.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8729119 PUBLICATION DATE: 11/13/2003
Name: SHELL ISLAND, ST. ANDREW B.
FL
NOAA Chart: 11391 Latitude: 30° 5.7' N ( 30.09500)
USGS Quad: BEACON BEACH Longitude: 85° 41.1' W ( -85.68500)
T I D A L D A T U M S
Tidal datums at SHELL ISLAND, ST. ANDREW B. based on:
LENGTH OF SERIES: 4 MONTHS
TIME PERIOD: November 1976 - February 1977
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8729840 PENSACOLA, PENSACOLA BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.400
MEAN HIGH WATER MHW = 0.389
MEAN TIDE LEVEL MTL = 0.203
MEAN SEA LEVEL MSL = 0.193
MEAN LOW WATER MLW = 0.017
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
NO 3 1976 1.131 0.742
R114 BAY CO 1972 3.415 3.026
R115 BAY CO 1972 4.579 4.190
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8729119 PUBLICATION DATE: 11/13/2003
Name: SHELL ISLAND, ST. ANDREW B.
FL
NOAA Chart: 11391 Latitude: 30° 5.7' N ( 30.09500)
USGS Quad: BEACON BEACH Longitude: 85° 41.1' W ( -85.68500)
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 NGS's Integrated Data Base (IDB PID)
provides geodetic datum based on traditionally leveled and bluebooked ties to
the National Spatial Reference System(NSRS) https://www.ngs.noaa.gov/datasheets/.
The NGS Online Positioning User Service (OPUS PID) provides geodetic datum based
on GPS position & tie it to the NSRS https://www.ngs.noaa.gov/OPUS/.
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.