U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 7
Station ID: 8722371 PUBLICATION DATE: 12/18/2023
Name: SEWALL POINT. ST. LUCIE RIVER
FL
NOAA Chart: 11474 Latitude: 27° 10.5' N ( 27.17500)
USGS Quad: ST. LUCIE INLET Longitude: 80° 11.3' W ( -80.18830)
TO REACH FROM THE MARTIN COUNTY COURT HOUSE IN STUART, GO EAST ALONG STATE
HIGHWAY A1A FOR 3.2 MI (5.1 KM) TO SOUTH SEWALL'S POINT ROAD, THENCE SOUTH ALONG
SOUTH SEWALL'S POINT ROAD 1.8 MI (2.9 KM) TO HIGH POINT, THENCE CONTINUE SOUTH
ALONG EAST HIGHPOINT ROAD 0.32 MI (0.51 KM) TO 32 EAST HIGH POINT ROAD. LEFT.
THE GAUGE IS LOCATED ON THE END OF A 65 M (213.3 FT) LONG DOCK BEHIND THE
RESIDENCE. BENCH MARKS ARE IN THE VICINITY TO THE NORTH AND NORTHWEST. ACCESS
TO THE GAUGE IS THROUGH A MAN-GATE ON THE WEST SIDE OF THE DRIVEWAY ENTRANCE
GATE TO RESIDENCE. OWNERS SHOULD BE NOTIFIED PRIOR TO ENTRY.
T I D A L B E N C H M A R K S
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 8722371 PUBLICATION DATE: 12/18/2023
Name: SEWALL POINT. ST. LUCIE RIVER
FL
NOAA Chart: 11474 Latitude: 27° 10.5' N ( 27.17500)
USGS Quad: ST. LUCIE INLET Longitude: 80° 11.3' W ( -80.18830)
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: SEAWALL USE 1898 NO 5 1969
DESIGNATION: SEAWALL RM 5
MONUMENTATION: Reference Mark disk VM#: 5448
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete Monument OPUS PID:
LATITUDE: 27° 10.5' N ( 27.17444) LONGITUDE: 80° 11.3' W ( -80.18880)
The bench mark is located 84.7 m (278.0 ft) SE of the centerline of east high
point road near the common lot line between residences located at number 30 and
number 32 East High Point Road, 9.8 m (32.0 ft) SSW of the SW corner of house
number 30 and 1.8 m (6.0 ft) north of a pair of sabal palms.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
Station ID: 8722371 PUBLICATION DATE: 12/18/2023
Name: SEWALL POINT. ST. LUCIE RIVER
FL
NOAA Chart: 11474 Latitude: 27° 10.5' N ( 27.17500)
USGS Quad: ST. LUCIE INLET Longitude: 80° 11.3' W ( -80.18830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: B 306 1970
DESIGNATION: B 306
MONUMENTATION: Bench Mark disk VM#: 5452
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete bulkhead OPUS PID#: AF3184
LATITUDE: 27° 10.8' N ( 27.17925) LONGITUDE: 80° 11.3' W ( -80.18769)
The bench mark is a disk set in the top of a concrete bulkhead, 19.20 m (63.0
ft) east of the centerline of Sewall Point Road, 11 m (36 ft) NW of the NW
corner of a bridge over a canal, 6.40 m (21.0 ft) north of the centerline of a
road leading east, and 0.3 m (1 ft) NE of the SW corner of the bulkhead.
BENCH MARK STAMPING: NO 2 A RESET 1984
DESIGNATION: 872 2371 TIDAL 2 A RESET
MONUMENTATION: Vertical Control disk VM#: 5453
AGENCY: National Geodetic Survey (NGS) IDB PID#:
SETTING CLASSIFICATION: Concrete Curb OPUS PID#: AF7403
LATITUDE: 27° 10.5' N ( 27.17572) LONGITUDE: 80° 11.3' W ( -80.18861)
The bench mark is a disk set in the concrete curbing, 27.43 m (90.0 ft) SSW of
the centerline of the driveway to house number 22, 7.32 m (24.0 ft) NNE of the
centerline of the driveway to house number 24, and 3.47 m (11.4 ft) ESE of the
centerline of the road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 8722371 PUBLICATION DATE: 12/18/2023
Name: SEWALL POINT. ST. LUCIE RIVER
FL
NOAA Chart: 11474 Latitude: 27° 10.5' N ( 27.17500)
USGS Quad: ST. LUCIE INLET Longitude: 80° 11.3' W ( -80.18830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: Q 236 1965
DESIGNATION: Q 236
MONUMENTATION: Bench Mark disk VM#: 18903
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete Monument OPUS PID:
LATITUDE: 27° 11.5' N ( 27.19167) LONGITUDE: 80° 11.7' W ( -80.19500)
The bench mark is a disk set in the top of a concrete post projection four
inches above the level of the ground, 12.19 m (40.0 ft) NE of the approximate
center of the junction, 7.62 m (25.0 ft) east of the center line of the road,
5.18 m (17.0 ft) north of the extended center line of the road leading west,
0.61 m (2.0 ft) south of a power line pole, 0.49 m (1.6 ft) north of a metal
witness post and about level with the road.
BENCH MARK STAMPING: NO 1 A RESET 1984
DESIGNATION: 872 2371 TIDAL 1 A RESET
MONUMENTATION: Tidal Station disk VM#: 18904
AGENCY: National Geodetic Survey (NGS) IDB PID#:
SETTING CLASSIFICATION: Concrete Monument OPUS PID:
LATITUDE: 27° 10.5' N ( 27.17500) LONGITUDE: 80° 11.3' W ( -80.18833)
The bench mark is a disk set flush with the ground and level with the surface of
the sewall point road, located 7.56 m (24.8 ft) east of the approximate
centerline of Sewall Point Road, 6.61 m (21 7 ft) north of the approximate
centerline of the driveway to house number 24, 4.51 m (14.8 ft) SE of a NGS
vertical control mark NO 2 A RESET 1984, 1.9 m (6.3 ft) east of a Bell South
telephone junction post and 0.30 m (1.0 ft) east of a carsonite witness post.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 8722371 PUBLICATION DATE: 12/18/2023
Name: SEWALL POINT. ST. LUCIE RIVER
FL
NOAA Chart: 11474 Latitude: 27° 10.5' N ( 27.17500)
USGS Quad: ST. LUCIE INLET Longitude: 80° 11.3' W ( -80.18830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 872 2371 3A 2021
DESIGNATION: 872 2371 3A
MONUMENTATION: Flange-encased Rod VM#: 24627
AGENCY: FLDEP IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: DR6672
LATITUDE: 27° 10.5' N ( 27.17483) LONGITUDE: 80° 11.4' W ( -80.18941)
The mark is a stainless steel rod located approximately 16.8 m (55 ft) SSE of
the center of East High Point Road, 2.9 m (9.5 ft) westerly of the drive way to
residence, 1.8 m (5.8 ft) southerly from the southerly edge of a paver walk on
the south side of a front entrance wall for the residence. The datum point is
the top of a stainless steel rod driven 17.3 m (56.8 ft) to refusal, and encased
in a 13.0 cm (5.0 in) PVC with a FLDEP logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
Station ID: 8722371 PUBLICATION DATE: 12/18/2023
Name: SEWALL POINT. ST. LUCIE RIVER
FL
NOAA Chart: 11474 Latitude: 27° 10.5' N ( 27.17500)
USGS Quad: ST. LUCIE INLET Longitude: 80° 11.3' W ( -80.18830)
T I D A L D A T U M S
Tidal datums at SEWALL POINT. ST. LUCIE RIVER based on:
LENGTH OF SERIES: 10 MONTHS
TIME PERIOD: November 2021 - August 2022
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8723214 VIRGINIA KEY, BISCAYNE BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
North American Vertical Datum NAVD88 = 0.598
MEAN HIGHER HIGH WATER MHHW = 0.508
MEAN HIGH WATER MHW = 0.461
MEAN SEA LEVEL MSL = 0.256
MEAN TIDE LEVEL MTL = 0.254
MEAN LOW WATER MLW = 0.047
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
SEAWALL USE 1898 NO 5 1969 11.189 10.728
B 306 1970 1.652 1.191
NO 2 A RESET 1984 7.960 7.499
Q 236 1965 1.406 0.945
NO 1 A RESET 1984 7.786 7.325
872 2371 3A 2021 11.196 10.735
Foot Notes:
Bench marks NO 1 A RESET 1984 and Q 236 1965 are based on one differential
leveling connection and do not meet the quality control standards of the NOS.
Therefore, caution should be used when deriving elevations for these marks.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
Station ID: 8722371 PUBLICATION DATE: 12/18/2023
Name: SEWALL POINT. ST. LUCIE RIVER
FL
NOAA Chart: 11474 Latitude: 27° 10.5' N ( 27.17500)
USGS Quad: ST. LUCIE INLET Longitude: 80° 11.3' W ( -80.18830)
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.