U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 08/31/1990
Station ID: 8724991 SUPERCEDED DATE: 04/21/2003
Name: MARCO, BIG MARCO RIVER
FLORIDA
NOAA Chart: 11429 Latitude: 25° 58.4' N
USGS Quad: MARCO ISLAND Longitude: 81° 43.7' W
To reach the tidal bench marks from the junction of State Roads 92 and 951 on
Marco Island, proceed north and NE on State Road 951 for 1.5 miles (2.4 km) to
Bald Eagle Drive, then north on Bald Eagle Drive for 1.35 miles (2.17 km) to
Snook Inn Restaurant and Motel. The bench marks are at Snook Inn Restaurant and
along Bald Eagle Drive. The tide gage and staff were at the boat docks behind
Snook Inn Restaurant.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 4991 A 1989
MONUMENTATION: Survey Disk VM#: 9758
AGENCY: PID#: AA7622
SETTING CLASSIFICATION: Stainless Steel Rod
The bench mark is 69.0 feet (21.0 m) NE of Doxee Food Store, 66.1 feet (20.1 m)
SSW of the NW corner of Snook Inn Motel, and 9.6 feet (2.9 m) NNW of the center
of a tri-trunked tree. The bench mark is crimped to a stainless steel rod
driven an unspecified depth to refusal, and encased in a PVC pipe and concrete
kickblock.
BENCH MARK STAMPING: 4991 B 1989
MONUMENTATION: Survey Disk VM#: 9759
AGENCY: PID#: AA7623
SETTING CLASSIFICATION: Stainless Steel Rod
The bench mark is 0.1 mile (0.2 km) south of Bench Mark 4991 A 1989, 165 feet
(50 m) south of the extended centerline of Tampa Place Road, 114.8 feet (35.0 m)
north of the center of the driveway to Marco Vista Apartment #1128, 28.6 feet
(8.7 m) west of the centerline of Bald Eagle Drive, and 10.4 feet (3.2 m) south
of an historic rock monument for Captain William D. Collins. The bench mark is
crimped to a stainless steel rod driven an unspecified depth 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 4
PUBLICATION DATE: 08/31/1990
Station ID: 8724991 SUPERCEDED DATE: 04/21/2003
Name: MARCO, BIG MARCO RIVER
FLORIDA
NOAA Chart: 11429 Latitude: 25° 58.4' N
USGS Quad: MARCO ISLAND Longitude: 81° 43.7' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4991 C 1989
MONUMENTATION: Survey Disk VM#: 9760
AGENCY: PID#: AA7624
SETTING CLASSIFICATION: Concrete Base
The bench mark is set flush in the 4 x 3-foot (1 x 1 m) concrete base for a
sign, 0.7 mile (1.1 km) south of Bench Mark 4991 B 1989, 59.6 feet (18.2 km)
east of the centerline of Bald Eagle Drive, 55 feet (17 m) west of the Marco
River Marine building, and 23.3 feet (7.1 m) south of twin palm trees.
BENCH MARK STAMPING: 4991 D 1989
MONUMENTATION: Survey Disk VM#: 9761
AGENCY: PID#: AA7625
SETTING CLASSIFICATION: oncrete Box Drain
The bench mark is set in the top of a concrete box drain, 0.15 mile (0.24 km)
south of Bench Mark 4991 C 1989, 122.7 feet (37.4 m) north of the centerline of
the driveway to Lawal Plaza, 42.4 feet (12.9 m) west of the centerline of Bald
Eagle Drive, and 26.2 feet (8.0 m) south of the extended centerline of Barfield
Drive.
BENCH MARK STAMPING: 4991 E 1989
MONUMENTATION: Survey Disk VM#: 9762
AGENCY: PID#: AA7621
SETTING CLASSIFICATION: Concrete Base
The bench mark is set in the concrete base for a former sign behind Snook Inn
Restaurant, 41 feet (12 m) SW of the pier, 17 feet (5 m) east of the Snook Inn
dining room, and 14.1 feet (4.3 m) SW of the edge of a wooden deck.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 08/31/1990
Station ID: 8724991 SUPERCEDED DATE: 04/21/2003
Name: MARCO, BIG MARCO RIVER
FLORIDA
NOAA Chart: 11429 Latitude: 25° 58.4' N
USGS Quad: MARCO ISLAND Longitude: 81° 43.7' W
T I D A L D A T U M S
Tidal datums at MARCO, BIG MARCO RIVER based on:
LENGTH OF SERIES: 106 HIGH & LOW WATER
TIME PERIOD: JUNE 8 - AUGUST 1, 1989
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8725110 NAPLES
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (07/19/1989) = 3.56
MEAN HIGHER HIGH WATER MHHW = 2.86
MEAN HIGH WATER MHW = 2.64
MEAN TIDE LEVEL MTL = 1.57
MEAN LOW WATER MLW = 0.51
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (06/19/1989) = -0.52
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
4991 A 1989 9.22 6.58
4991 B 1989 7.91 5.27
4991 C 1989 6.84 4.20
4991 D 1989 4.50 1.86
4991 E 1989 4.35 1.71
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 08/31/1990
Station ID: 8724991 SUPERCEDED DATE: 04/21/2003
Name: MARCO, BIG MARCO RIVER
FLORIDA
NOAA Chart: 11429 Latitude: 25° 58.4' N
USGS Quad: MARCO ISLAND Longitude: 81° 43.7' 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.