U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 06/11/1987
Station ID: 8726217 SUPERCEDED DATE: 04/21/2003
Name: CORTEZ, SARASOTA BAY
FLORIDA
NOAA Chart: 11424 Latitude: 27° 28.1' N
USGS Quad: BRADENTON BEACH Longitude: 82° 41.3' W
To reach the tidal bench marks from the Cortez post office, proceed west on
State Road 684 about 0.4 mile (0.6 km) to Cortez Fishing Center on the left.
The bench marks are on the north and south sides of State Road 684 at the bridge
over Anna Maria Sound. The tide gage and staff were located off the dock of
Cortez Marina.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1953
MONUMENTATION: Survey Disk VM#: 6139
AGENCY: PID#: AG2000
SETTING CLASSIFICATION: Concrete Sea Wall
The bench mark is set in a concrete sea wall at the U.S. Coast Guard Cortez
Station, 81.5 feet (24.8 m) SW of the SW corner of the station, 64.0 feet (19.5
m) ESE of the flagpole, 26.0 feet (7.9 m) west of the centerline of the black
topped walk leading to the north end of the fishing pier, and at ground level.
BENCH MARK STAMPING: NO 2 1953
MONUMENTATION: Survey Disk VM#: 6144
AGENCY: PID#: AG1999
SETTING CLASSIFICATION: Concrete Sea Wall
The bench mark is set in a concrete sea wall at the U.S. Coast Guard Cortez
station, 112.5 feet (34.3 m) WSW of the SW corner of the station, 90.5 feet
(27.6 m) west of the centerline of the black topped walk leading to the north
end of the fishing pier, 69.8 feet (21.3 m) west of Bench Mark NO 1 1953, 6.0
feet (1.8 m) west of the flagpole, 2.5 feet (0.8 m) north of where the sea wall
makes a right angle turn, and at ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 06/11/1987
Station ID: 8726217 SUPERCEDED DATE: 04/21/2003
Name: CORTEZ, SARASOTA BAY
FLORIDA
NOAA Chart: 11424 Latitude: 27° 28.1' N
USGS Quad: BRADENTON BEACH Longitude: 82° 41.3' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 3 1953
MONUMENTATION: Survey Disk VM#: 6145
AGENCY: PID#: AG1998
SETTING CLASSIFICATION: Concrete Slab
The bench mark is set in the NE corner of a 6-foot (2 m) square concrete slab at
the foot of the steps at the south entrance to a house bearing the name South
Wind, north of and across Bayview Avenue from the U.S. Coast Guard Cortez
Station, 76 feet (23 m) east of the centerline of 124th Street CT. W., 46.5 feet
(14.2 m) north of the centerline of Bayview Avenue, and 1 foot (0.3 m) above the
level of the avenue.
BENCH MARK STAMPING: K 254 1965
MONUMENTATION: Survey Disk VM#: 6146
AGENCY: PID#: AG1995
SETTING CLASSIFICATION: Concrete Bridge Abutment
The bench mark is set flush in the top of the south end of the east concrete
bridge abutment, 45.5 feet (13.9 m) NW of power pole 12707-1, 42.0 feet (12.8 m)
north of Bench Mark 6217 A 1977, 20.5 feet (6.2 m) south of the centerline of
State Road 684, and 1.3 feet (0.4 m) north of the edge of the bridge support.
BENCH MARK STAMPING: 6217 A 1977
MONUMENTATION: Survey Disk VM#: 6147
AGENCY: PID#: AG7726
SETTING CLASSIFICATION: Concrete Anchor Block
The bench mark is set flush in a 2 x 2-foot (1 x 1 m) concrete anchor block near
the east end and south of the State Road 684 bridge, 45.0 feet (13.7 m) NW of
power pole 12717, 16.0 feet (4.9 m) north of the centerline of Old Cortez Bridge
Road, and 10.0 feet (3.0 m) west of the guardrail, and 2 feet (1 m) above ground
level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 06/11/1987
Station ID: 8726217 SUPERCEDED DATE: 04/21/2003
Name: CORTEZ, SARASOTA BAY
FLORIDA
NOAA Chart: 11424 Latitude: 27° 28.1' N
USGS Quad: BRADENTON BEACH Longitude: 82° 41.3' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6217 B 1977
MONUMENTATION: Survey Disk VM#: 6148
AGENCY: PID#: AG7727
SETTING CLASSIFICATION: Concrete Sea Wall
The bench mark is set flush in the top of the sea wall near the east end of the
State Road 684 bridge, 43.0 feet (13.1 m) south of the SE corner of the bridge,
38.4 feet (11.7 m) NE of Bench Mark 6217 A 1977, 27.3 feet (8.3 m) SW of power
pole 12707, 1.3 feet (0.4 m) west of the SE end of the sea wall, and 10 feet (3
m) below the road.
BENCH MARK STAMPING: 6217 C 1977
MONUMENTATION: Survey Disk VM#: 6149
AGENCY: PID#: AG7728
SETTING CLASSIFICATION: Concrete Sea Wall
The bench mark is set flush in the concrete sea wall near the east end and north
side of the State Road 684 bridge at a boat basin, 120.0 feet (36.6 m) NW of
Bench Mark 6217 E, 64.0 feet (19.5 m) north of the centerline of State Road 684,
55.0 feet (16.8 m) NW of power transformer 13R36 3223, 11.6 feet (3.5 m) west of
the east end of the sea wall, and 8 feet (2 m) below the road.
BENCH MARK STAMPING: 6217 E
MONUMENTATION: Survey Disk VM#: 6150
AGENCY: PID#: AG7725
SETTING CLASSIFICATION: Concrete Drain
The bench mark is set flush in concrete drain, 205.0 feet (62.5 m) east of Bench
Mark K 254 1965, 25.5 feet (7.8 m) north of the centerline of Old Cortez Bridge
Road, 17.7 feet (5.4 m) south of the centerline of State Road 684, and 7.8 feet
(2.4 m) NE of a culvert, and 3 feet (1 m) below the road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 06/11/1987
Station ID: 8726217 SUPERCEDED DATE: 04/21/2003
Name: CORTEZ, SARASOTA BAY
FLORIDA
NOAA Chart: 11424 Latitude: 27° 28.1' N
USGS Quad: BRADENTON BEACH Longitude: 82° 41.3' W
T I D A L D A T U M S
Tidal datums at CORTEZ, SARASOTA BAY based on:
LENGTH OF SERIES: 6 MONTHS
TIME PERIOD: MAY - OCTOBER 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 (06/03/1977) = 3.22
MEAN HIGHER HIGH WATER MHHW = 2.16
MEAN HIGH WATER MHW = 1.87
MEAN TIDE LEVEL MTL = 1.11
MEAN LOW WATER MLW = 0.35
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (07/01/1977) = -0.51
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
NO 1 1953 4.97 3.10
NO 2 1953 5.02 3.15
NO 3 1953 6.06 4.19
K 254 1965 15.63 13.76
6217 A 1977 9.45 7.58
6217 B 1977 5.33 3.46
6217 C 1977 5.35 3.48
6217 E 10.87 9.00
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 06/11/1987
Station ID: 8726217 SUPERCEDED DATE: 04/21/2003
Name: CORTEZ, SARASOTA BAY
FLORIDA
NOAA Chart: 11424 Latitude: 27° 28.1' N
USGS Quad: BRADENTON BEACH Longitude: 82° 41.3' 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.