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Datums Page Page 1 of 10
Station ID: 9761115 PUBLICATION DATE: 03/05/2013
Name: BARBUDA
NOAA Chart: 25570 Latitude: 17° 35.4' N ( 17.59069)
USGS Quad: Longitude: 61° 49.2' W ( -61.82056)
To reach the tide station from the intersection of Top Mission Street and River
Road in the village of Codrington, proceed south on River Road for 3.7 km (2.3
mi) to the end of the asphalt. Continue south on River Road, now dirt, for 1.8
km (1.1 mi) to the fork in the road. Bear to the right (through an open chain
link fence gate) and proceed 0.3 km (0.2 mi) to a "T" intersection. Turn WSW
(right) and proceed 0.2 km (0.1 mi) to the River Wharf and the tide station on
the left. The bench marks are located in the vicinity of the tide station, with
the majority of the marks in a line running NW to SE.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 1115 A 2011
DESIGNATION: 976 1115 A
MONUMENTATION: Survey disk VM#: 20085
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Set in concrete footing OPUS PID:
LATITUDE: 17° 35.4' N ( 17.59067) LONGITUDE: 61° 49.2' W ( -61.82056)
The primary bench mark is a brass disk set flush in the SW concrete footing for
the tide station, 18.20 m (59.8 ft) east of the center of the SE side of a
bridge over two culverts, 9.70 m (31.9 ft) SE of the center of the road, 0.30 m
(1.0 ft) NE of the SW edge of the SW footing, 0.29 m (0.95 ft) SW of the NE edge
of the SW footing, 0.26 m (0.85 ft) NW from the SE end of the SW footing, and
0.28 m (0.9 ft) SE of the SE face of the tide station's SW leg.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 10
Station ID: 9761115 PUBLICATION DATE: 03/05/2013
Name: BARBUDA
NOAA Chart: 25570 Latitude: 17° 35.4' N ( 17.59069)
USGS Quad: Longitude: 61° 49.2' W ( -61.82056)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1115 B 2011
DESIGNATION: 976 1115 B
MONUMENTATION: Flange-encased Rod VM#: 20086
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 17° 35.5' N ( 17.59119) LONGITUDE: 61° 49.2' W ( -61.82006)
The bench mark is a flange-encased rod located 43.6 m (143.0 ft) NE of the third
phone pole SW of River Road, 18.0 m (59.2 ft) SE from the center of the concrete
company's equipment yard's SW gate, 1.70 m (5.7 ft) SW of the second phone pole
SW of River Road, 0.60 m (2.0 ft) NW of an orange fiberglass witness post, 0.26
m (0.85 ft) below the road surface, and 0.03 m (0.1 ft) below ground level. The
datum point is the top of a stainless steel rod driven 1.67 m (5.5 ft) to
refusal, and encased in a 13 cm (5 inches) PVC pipe with concrete kick block.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 10
Station ID: 9761115 PUBLICATION DATE: 03/05/2013
Name: BARBUDA
NOAA Chart: 25570 Latitude: 17° 35.4' N ( 17.59069)
USGS Quad: Longitude: 61° 49.2' W ( -61.82056)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1115 C 2011
DESIGNATION: 976 1115 C
MONUMENTATION: Flange-encased Rod VM#: 20087
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 17° 35.5' N ( 17.59092) LONGITUDE: 61° 49.2' W ( -61.81961)
The bench mark is a flange-encased rod located at the top of the beach on the SE
side of the entrance road to the river wharf, NNW of the SW end of a chain link
fence, near where the sand meets the grass, 98.90 m (324.5 ft) NW of bench mark
976 1115 D, 26.60 m (87.4 ft) NE of the normal high water mark along the beach,
0.80 m (2.75 ft) NNW of a fence post and the SW end of a fence running NE to SW,
0.60 m (2.0 ft) SW of an orange fiberglass witness post, and 0.10 m (0.34 ft)
above ground level. The datum point is the top of a stainless steel rod driven
3.13 m (10.3 ft) to refusal, and encased in a 13 cm (5 inches) PVC pipe with
concrete kick block.
BENCH MARK STAMPING: 1115 D 2011
DESIGNATION: 976 1115 D
MONUMENTATION: Survey disk VM#: 20088
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Set in rock outcrop OPUS PID:
LATITUDE: 17° 35.4' N ( 17.59050) LONGITUDE: 61° 49.1' W ( -61.81878)
The bench mark is a brass disk set flush in the NW end of a rock outcrop along
the water, SE of the beach on the SE side of the entrance road to the River
Wharf, 98.90 m (324.5 ft) SE of benchmark 976 1115 C, 68.90 m (226.0 ft) NW of
benchmark 976 1115 E, 66.70 m (218.8 ft) west of a wire fence that runs parallel
to a dirt road, and 5.70 m (18.7 ft) east of the west edge of a pointy rock
above the water.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 10
Station ID: 9761115 PUBLICATION DATE: 03/05/2013
Name: BARBUDA
NOAA Chart: 25570 Latitude: 17° 35.4' N ( 17.59069)
USGS Quad: Longitude: 61° 49.2' W ( -61.82056)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1115 E 2011
DESIGNATION: 976 1115 E
MONUMENTATION: Survey disk VM#: 20089
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Set in rock outcrop OPUS PID:
LATITUDE: 17° 35.4' N ( 17.59000) LONGITUDE: 61° 49.1' W ( -61.81839)
The bench mark is a brass disk set flush in a rock outcrop along the water and
SE of the beach on the SE side of the entrance road to the River Wharf, 82.40 m
(270.5 ft) NW of benchmark 976 1115 F, 68.90 m (226.0 ft) SE of benchmark 976
1115 D, 58.90 m (193.4 ft) WSW of a wire fence that runs parallel to a dirt
road, and 3.50 m (11.6 ft) WSW of the intersection where the rock outcrop and
grass meet.
BENCH MARK STAMPING: 1115 F 2011
DESIGNATION: 976 1115 F
MONUMENTATION: Survey disk VM#: 20090
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Set in rock outcrop OPUS PID:
LATITUDE: 17° 35.4' N ( 17.58950) LONGITUDE: 61° 49.1' W ( -61.81783)
The bench mark is a brass disk set flush in a rock outcrop along the water and
SE of the beach on the SE side of the entrance road to the River Wharf, 82.30 m
(270.5 ft) SE of bench mark 976 1115 E, 18.00 m (59.15 ft) NNW of the NW corner
of a concrete block foundation built on the rock outcrop next to the water's
edge, and 3.30 m (10.7 ft) SW of the intersection where the rock outcrop and
grass meet.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 10
Station ID: 9761115 PUBLICATION DATE: 03/05/2013
Name: BARBUDA
NOAA Chart: 25570 Latitude: 17° 35.4' N ( 17.59069)
USGS Quad: Longitude: 61° 49.2' W ( -61.82056)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1115 G 2011
DESIGNATION: 976 1115 G
MONUMENTATION: Survey disk VM#: 20091
AGENCY: IDB PID#:
SETTING CLASSIFICATION: Set in concrete filled bollard OPUS PID:
LATITUDE: 17° 35.5' N ( 17.59158) LONGITUDE: 61° 49.2' W ( -61.82083)
The bench mark is a brass disk located SW of the access road that runs NW/SE
along the beach and ends at the 'T' intersection, 35.30 m (115.8 ft) SE of bench
mark 976 1115 H, 23.60 m (77.4 ft) north of a 1.70 m (5.7 ft) high concrete
block pillar used as a bollard to secure boats to, 12.10 m (39.8 ft) SW of the
chain link fence along the concrete company's equipment yard's SW side, and 24
cm (9 inches) above the ground level. The benchmark is set flush in the top of
a 25 cm (10 inch) diameter concrete and metal-encased bollard.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 10
Station ID: 9761115 PUBLICATION DATE: 03/05/2013
Name: BARBUDA
NOAA Chart: 25570 Latitude: 17° 35.4' N ( 17.59069)
USGS Quad: Longitude: 61° 49.2' W ( -61.82056)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1115 H 2011
DESIGNATION: 976 1115 H
MONUMENTATION: Survey disk VM#: 20092
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Set in concrete filled bollard OPUS PID:
LATITUDE: 17° 35.5' N ( 17.59181) LONGITUDE: 61° 49.3' W ( -61.82108)
The bench mark is a brass disk located SW of the access road that runs NW/SE
along the beach and ends at the 'T' intersection, 35.30 m (115.8 ft) NW of bench
mark 976 1115 G, 28.00 m (91.85 ft) SE of the concrete company's fence corner
where the fence turns NNE (the corner is NW of the NW entrance gate along the
access road (across from the beach) to the concrete company's equipment yard),
6.80 m (22.45 ft) SW of the chain link fence around the equipment yard, and 0.70
m (2.4 ft) above the ground/concrete foundation level. The benchmark is set
flush in the top of a 0.40 m (1.25 ft) diameter concrete and metal-encased
bollard with an axle passing through the top center (to tie the rope to), that
is set in a 1.5 m x 2.0 m concrete foundation.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 10
Station ID: 9761115 PUBLICATION DATE: 03/05/2013
Name: BARBUDA
NOAA Chart: 25570 Latitude: 17° 35.4' N ( 17.59069)
USGS Quad: Longitude: 61° 49.2' W ( -61.82056)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1115 J 2011
DESIGNATION: 976 1115 J
MONUMENTATION: Flange-encased Rod VM#: 20093
AGENCY: IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 17° 35.5' N ( 17.59206) LONGITUDE: 61° 49.3' W ( -61.82167)
The bench mark is a flange-encased rod located along the SW edge of the access
road leading to the River Wharf, 47.50 m (155.8 ft) SE of the NE gate post that
separates river road with the NW end of the access road that leads to the River
Wharf, 40.70 m (133.6 ft) WNW of the concrete company's fence corner where the
fence turns NNE (the corner is NW of the NW entrance gate along the access road
(across from the beach) to the concrete company's equipment yard), 5.15 m (16.9
ft) SSW of the center of the dirt access road connecting River Road with the
entrance to the River Wharf, 1.25 m (4.1 ft) NE of an orange fiberglass witness
post, and 6 cm (2 inches) below ground level. The datum point is the top of a
stainless steel rod driven 4.23 m (13.9 ft) to refusal, and encased in a 13 cm
(5 inches) PVC pipe with concrete kick block.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 8 of 10
Station ID: 9761115 PUBLICATION DATE: 03/05/2013
Name: BARBUDA
NOAA Chart: 25570 Latitude: 17° 35.4' N ( 17.59069)
USGS Quad: Longitude: 61° 49.2' W ( -61.82056)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1115 K 2011
DESIGNATION: 976 1115 K
MONUMENTATION: Flange-encased Rod VM#: 20094
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 17° 35.5' N ( 17.59236) LONGITUDE: 61° 49.3' W ( -61.82219)
The bench mark is a flange-encased rod located 22.20 m (72.8 ft) east of a 0.90
m (3.0 ft) diameter palm tree at its base, the tallest and southernmost of three
palm trees in a row, 21.70 m (71.2 ft) WNW of the NE gate post that separates
river road with the NW end of the access road leading to the River Wharf, 7.90 m
(25.9 ft) SW of the intersection of River Road and the access road that leads to
the River Wharf, 0.90 m (3.0 ft) NE of an orange fiberglass witness post, and 14
cm (6 inches) below the ground surface. The datum point is the top of a
stainless steel rod driven 6.75 m (22.1 ft) to refusal, and encased in a 13 cm
(5 inches) PVC pipe with concrete kick block.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 9 of 10
Station ID: 9761115 PUBLICATION DATE: 03/05/2013
Name: BARBUDA
NOAA Chart: 25570 Latitude: 17° 35.4' N ( 17.59069)
USGS Quad: Longitude: 61° 49.2' W ( -61.82056)
T I D A L D A T U M S
Tidal datums at BARBUDA based on:
LENGTH OF SERIES: 1 YEAR
TIME PERIOD: July 2011 - June 2012
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9751401 LIME TREE BAY, ST CROIX
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (08/23/2012) = 0.545
MEAN HIGHER HIGH WATER MHHW = 0.225
MEAN HIGH WATER MHW = 0.219
MEAN SEA LEVEL MSL = 0.133
MEAN TIDE LEVEL MTL = 0.127
MEAN LOW WATER MLW = 0.035
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (12/25/2011) = -0.177
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
1115 A 2011 1.468 1.249
1115 B 2011 1.144 0.925
1115 C 2011 1.344 1.125
1115 D 2011 1.687 1.468
1115 E 2011 2.262 2.043
1115 F 2011 1.713 1.494
1115 G 2011 1.803 1.584
1115 H 2011 2.425 2.206
1115 J 2011 1.663 1.444
1115 K 2011 1.036 0.817
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 10 of 10
Station ID: 9761115 PUBLICATION DATE: 03/05/2013
Name: BARBUDA
NOAA Chart: 25570 Latitude: 17° 35.4' N ( 17.59069)
USGS Quad: Longitude: 61° 49.2' W ( -61.82056)
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.
Station Location
Published bench mark
Unpublished bench mark
