U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 04/06/1984
Station ID: 8726486 SUPERCEDED DATE: 04/21/2003
Name: GULFPORT, BOCA CIEGA BAY
FLORIDA
NOAA Chart: 11414 Latitude: 27° 44.2' N
USGS Quad: PASS-A-GRILLE Longitude: 82° 42.5' W
To reach the tidal bench marks from the intersection of U.S. Highway 19 (34th
Street) and Gulfport Boulevard, travel west on Gulfport Boulevard to 54th Street
South, then south on 54th Street South to the intersection of Shore Boulevard
South. The bench marks are along the pier, and the roads near the waterfront,
and the tide gage was on the wooden boat landing at the Gulfport Municipal Pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 2 1952
MONUMENTATION: Survey Disk VM#: 6529
AGENCY: PID#: AG6346
SETTING CLASSIFICATION: Concrete Sea Wall
The bench mark is located in a concrete abutment on a sea wall in a drill hole
recessed 0.3 feet (0.1 m), 67.8 feet (20.7 m) south of the edge of a curb, 14.3
feet (4.4 m) north of the north corner of the east balastrade, 6.0 feet (1.8 m)
WSW of power pole 3A1102, and 0.2 foot (0.1 m) from the east edge of the pier.
BENCH MARK STAMPING: NO 4 1952
MONUMENTATION: Survey Disk VM#: 6530
AGENCY: PID#: AG6348
SETTING CLASSIFICATION: Concrete Sea Wall
The bench mark is cemented in a drill hole under an iron handrail on the SE
corner of a concrete sea wall around Gulfport Casino, 148.8 feet (45.4 m) south
of the north end of the sea wall, and 42.4 feet (12.9 m) SE of the SE corner of
the casino.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 04/06/1984
Station ID: 8726486 SUPERCEDED DATE: 04/21/2003
Name: GULFPORT, BOCA CIEGA BAY
FLORIDA
NOAA Chart: 11414 Latitude: 27° 44.2' N
USGS Quad: PASS-A-GRILLE Longitude: 82° 42.5' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6486 E 1982
MONUMENTATION: Survey Disk VM#: 6531
AGENCY: PID#: AG7407
SETTING CLASSIFICATION: Stainless Steel Rod
The bench mark is at the intersection of 29th Avenue South and 58th Street (28.0
feet (8.5 m) south of the centerline of 29th Avenue South, 18.8 feet (5.7 m)
east of the centerline of 54th Street, 3.5 feet (1.1 m) SW of a power pole, and
1.3 feet (0.4 m) north of a witness post. The Bench Mark is crimped to the top
of a rod driven 40 feet (12.2 m), encased in a pipe flush with the ground and
level with the road.
BENCH MARK STAMPING: 6486 F 1982
MONUMENTATION: Survey Disk VM#: 6532
AGENCY: PID#: AG7408
SETTING CLASSIFICATION: Stainless Steel Rod
The bench mark is at the intersection of 27th Avenue South and 54th Street,
110.5 feet 33.7 m) SW of the SW corner of the Gulfport Presbyterian Church, 43.0
feet (13.1 m) west of power pole 126752 with a street light, 23.0 feet (7.0 m)
south of the centerline of 27th Avenue South, 18.0 feet (5.5 m) west of the
centerline of 54th Street, and 1.8 feet (0.5 m) east of a witness post. The
bench mark is crimped to the top of a rod driven 44 feet (13.4 m), encased in a
pipe projecting 0.2 foot (0.1 m) and level with the road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 04/06/1984
Station ID: 8726486 SUPERCEDED DATE: 04/21/2003
Name: GULFPORT, BOCA CIEGA BAY
FLORIDA
NOAA Chart: 11414 Latitude: 27° 44.2' N
USGS Quad: PASS-A-GRILLE Longitude: 82° 42.5' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6486 G 1982
MONUMENTATION: Survey Disk VM#: 6533
AGENCY: PID#: AG7409
SETTING CLASSIFICATION: Concrete Box Drain
The bench mark is set in the top of the NW corner of a concrete box drain with
an iron grate, near the intersection of 25th Avenue South and 54th Street, 39.0
feet (11.9 m) west of the centerline of 54th Street, 20.7 feet (6.3 m) north of
the centerline of 25th Avenue South, 16.5 feet (5.0 m) SW of underground cable
marker 900, 1.5 feet (0.5 m) SE of a witness post and 2 feet (0.6 m) below the
road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 04/06/1984
Station ID: 8726486 SUPERCEDED DATE: 04/21/2003
Name: GULFPORT, BOCA CIEGA BAY
FLORIDA
NOAA Chart: 11414 Latitude: 27° 44.2' N
USGS Quad: PASS-A-GRILLE Longitude: 82° 42.5' W
T I D A L D A T U M S
Tidal datums at GULFPORT, BOCA CIEGA BAY based on:
LENGTH OF SERIES: 16 MONTHS
TIME PERIOD: DECEMBER 1975-JUNE 1977
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8726520 ST. PETERSBURG
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (12/20/1976) = 3.38
MEAN HIGHER HIGH WATER MHHW = 2.29
MEAN HIGH WATER MHW = 2.02
MEAN TIDE LEVEL MTL = 1.18
MEAN LOW WATER MLW = 0.34
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (01/19/1977) = -1.89
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
NO 2 1952 6.07 4.05
NO 4 1952 6.12 4.10
6486 E 1982 14.37 12.35
6486 F 1982 15.92 13.90
6486 G 1982 14.65 12.63
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 04/06/1984
Station ID: 8726486 SUPERCEDED DATE: 04/21/2003
Name: GULFPORT, BOCA CIEGA BAY
FLORIDA
NOAA Chart: 11414 Latitude: 27° 44.2' N
USGS Quad: PASS-A-GRILLE Longitude: 82° 42.5' 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.