U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8724266 PUBLICATION DATE: 04/01/2004
Name: SUMMERLAND KEY EAST
FL
NOAA Chart: 11445 Latitude: 24° 39.1' N ( 24.65170)
USGS Quad: SUMMERLAND KEY Longitude: 81° 26.1' W ( -81.43500)
To reach the tidal bench marks from the Summerland Key post office, proceed east
on U.S. Highway 1 for 0.8 km (0.5 mi), then turn right and proceed south on East
Shore Drive (S-942) for 1.3 km (0.8 mi) to the Martinez residence on the right.
The bench marks are located in the vicinity of the Martinez residence. The tide
gage and staff were located on the Martinez pier on Niles Channel.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1974
DESIGNATION: 872 4266 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 6876
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0966
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 24° 39.1' N ( 24.65170) LONGITUDE: 81° 26.1' W ( -81.43500)
The primary bench mark is a disk set in a concrete sidewalk located on the west
edge of a small boat ramp behind the Martinez residence, 12 m (38 ft) south of
a telephone pole, 4 m (13 ft) west of the water line. The bench mark is crimped
to an copper-clad deep rod driven to unspecified depth.
BENCH MARK STAMPING: NO 2 1974
DESIGNATION: 872 4266 TIDAL 2
MONUMENTATION: Tidal Station disk VM#: 6877
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0967
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 24° 39.1' N ( 24.65170) LONGITUDE: 81° 26.1' W ( -81.43500)
The bench mark is a disk set flush in a concrete sea wall located along the
Martinez boat slip, 42 m (139 ft) NW of bench mark NO 1 1974, and 0.30 m (1.0
ft) south of the north edge of the sea wall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8724266 PUBLICATION DATE: 04/01/2004
Name: SUMMERLAND KEY EAST
FL
NOAA Chart: 11445 Latitude: 24° 39.1' N ( 24.65170)
USGS Quad: SUMMERLAND KEY Longitude: 81° 26.1' W ( -81.43500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 3 1974
DESIGNATION: 872 4266 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 6878
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0968
SETTING CLASSIFICATION: Concrete patio OPUS PID:
LATITUDE: 24° 39.1' N ( 24.65170) LONGITUDE: 81° 26.1' W ( -81.43500)
The bench mark is a disk set flush in the concrete patio located aside the steps
at the NE corner of the Martinez residence, 44 m (145 ft) west of bench mark NO
2 1974, and 0.15 m (0.5 ft) east of the east edge of the concrete steps to the
patio.
BENCH MARK STAMPING: NO 4 1974
DESIGNATION: 872 4266 TIDAL 4
MONUMENTATION: Tidal Station disk VM#: 6879
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0970
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 24° 39.1' N ( 24.65170) LONGITUDE: 81° 26.1' W ( -81.43500)
The bench mark is a disk set flush in the concrete sea wall and patio of the
Howser residence located adjacent to the Martinez residence on the north side, 9
m (29 ft) north of bench mark NO 2 1974, 1 m (2 ft) north of the south edge of
the patio, and 0.30 m (1.0 ft) west of the east edge of the sea wall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8724266 PUBLICATION DATE: 04/01/2004
Name: SUMMERLAND KEY EAST
FL
NOAA Chart: 11445 Latitude: 24° 39.1' N ( 24.65170)
USGS Quad: SUMMERLAND KEY Longitude: 81° 26.1' W ( -81.43500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 5 1974
DESIGNATION: 872 4266 TIDAL 5
MONUMENTATION: Tidal Station disk VM#: 6880
AGENCY: National Ocean Survey (NOS) IDB PID#: AA0969
SETTING CLASSIFICATION: Concrete footing OPUS PID:
LATITUDE: 24° 39.1' N ( 24.65170) LONGITUDE: 81° 26.1' W ( -81.43500)
The bench mark is a disk set flush in a concrete footing of the Howser residence
located on the south edge of the boat slip, 39 m (127 ft) NW of bench mark NO 4
1974, and 4.42 m (14.5 ft) east of the west end of the boat slip.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8724266 PUBLICATION DATE: 04/01/2004
Name: SUMMERLAND KEY EAST
FL
NOAA Chart: 11445 Latitude: 24° 39.1' N ( 24.65170)
USGS Quad: SUMMERLAND KEY Longitude: 81° 26.1' W ( -81.43500)
T I D A L D A T U M S
Tidal datums at SUMMERLAND KEY EAST based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: September 1974 - September 1974
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8724580 KEY WEST
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.466
North American Vertical Datum NAVD88 = 0.460
MEAN HIGH WATER MHW = 0.391
MEAN SEA LEVEL MSL = 0.221
MEAN TIDE LEVEL MTL = 0.220
MEAN LOW WATER MLW = 0.049
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 1 1974 0.684 0.293
NO 2 1974 0.485 0.094
NO 3 1974 1.394 1.003
NO 4 1974 1.103 0.712
NO 5 1974 0.766 0.375
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8724266 PUBLICATION DATE: 04/01/2004
Name: SUMMERLAND KEY EAST
FL
NOAA Chart: 11445 Latitude: 24° 39.1' N ( 24.65170)
USGS Quad: SUMMERLAND KEY Longitude: 81° 26.1' W ( -81.43500)
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.