U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 9751693 PUBLICATION DATE: 07/14/2021
Name: MAGENS BAY
VI
NOAA Chart: 25650 Latitude: 18° 22.0' N ( 18.36633)
USGS Quad: CENTRAL ST THOMAS Longitude: 64° 55.3' W ( -64.92211)
To reach from the U.S. Coast Gard Station near the intersection of Highway 30 /
Veterans Drive and Forte Strade in Charlotte Amalie, head east on Highway 30 /
Veterans Drive for 0.2 km (0.1 mi) to the intersection with Hospital Gade, turn
left onto Hospital Gade and proceed north for 0.4 km (0.2 mi) to the
intersection with Maude Proudfoot Drive, turn left onto Maude Proudfoot Drive
and proceed NW for 0.3 km (0.2 mi) to where the road name changes to Mafolie
Road, continue straight onto Mafolie Road NNW for 1.4 km (0.9 m) to the
intersection with Magens Bay Road, turn right onto Magens Bay Road and proceed
north for 3.0 km (1.9 m) to the entrance to Magens Bay Park with a manned gate,
proceed through the gate and turn right heading NE for 0.2 km (0.1 mi) to a
parking area at the end of the road.
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 6
Station ID: 9751693 PUBLICATION DATE: 07/14/2021
Name: MAGENS BAY
VI
NOAA Chart: 25650 Latitude: 18° 22.0' N ( 18.36633)
USGS Quad: CENTRAL ST THOMAS Longitude: 64° 55.3' W ( -64.92211)
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING:
DESIGNATION: GEN
MONUMENTATION: Tidal Station disk VM#: 23541
AGENCY: US Coast & Geodetic Survey IDB PID#: TV0513
SETTING CLASSIFICATION: Boulder OPUS PID#: TV0513
LATITUDE: 18° 22.0' N ( 18.36628) LONGITUDE: 64° 55.3' W ( -64.92211)
The bench mark is a disk set in the NE edge of a 4.00 m (13.1 ft) x 3.00 m (9.8
ft) x 1.50 m (4.9 ft) high offshore rock, 125.0 m (410.1 ft) North of the NW
corner of picnic shed number 1 at Magens Bay Park, 24.00 m (78.7 ft) NW of the
Northern end of the Sandy Beach and 3.00 m (9.8 ft) SE of the NE shore of Magens
Bay.
BENCH MARK STAMPING: 1693 A 2020
DESIGNATION: 975 1693 A
ALIAS: 1693 A
MONUMENTATION: Tidal Station disk VM#: 23542
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Concrete Pad OPUS PID:
LATITUDE: 18° 21.9' N ( 18.36500) LONGITUDE: 64° 55.3' W ( -64.92192)
The bench mark is a disk set in a concrete pad that supports the SE corner of
picnic shed #1 at Magens Bay Park 28.71 m (94.2 ft) NNW of the NE corner of a
concrete bathhouse, 25.24 m (83.4 ft) NNW of the NW corner of a concrete fence
that encloses protected vegitation, 13.53 m (44.4 ft) NNW of a 20.32 cm (8
inches) x 20.32 cm (8 inches) wooded post along at an angle point along the West
edge of an asphalt road and 4.25 m (13.9 ft) ESE of a 1.25 m (4.1 ft) x 1.25 m
(4.1 ft) x 1.00 m (3.3 ft) red brick fire place.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 9751693 PUBLICATION DATE: 07/14/2021
Name: MAGENS BAY
VI
NOAA Chart: 25650 Latitude: 18° 22.0' N ( 18.36633)
USGS Quad: CENTRAL ST THOMAS Longitude: 64° 55.3' W ( -64.92211)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1693 B 2020
DESIGNATION: 975 1693 B
ALIAS: 1693 B
MONUMENTATION: Tidal Station disk VM#: 23543
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Concrete Pad OPUS PID#: BBHB68
LATITUDE: 18° 21.7' N ( 18.36139) LONGITUDE: 64° 55.4' W ( -64.92372)
The bench mark is a disk set in the SW corner of a 1.20 m (3.9 ft) x 1.20 m (3.9
ft) x .60 m (2.0 ft) utility vault located 0.5 km (0.3 mi) SW from the entrance
to Magens Bay Park, 15.24 m (50.0 ft) South of a 1.25 m (4.1 ft) x 1.25 m (4.1
ft) x 1.00 m (3.3 ft) red brick fire pit, 15.20 m (49.9 ft) WNW of the
centerline of a 6.00 m (19.7 ft) wide asphalt road, 13.56 m (44.5 ft) SSE of the
SE corner of picnic shed number 3 and 4.03 m (13.2 ft) NE of a plam tree.
BENCH MARK STAMPING: 1693 C 2020
DESIGNATION: 975 1693 C
ALIAS: 1693 C
MONUMENTATION: Tidal Station disk VM#: 23544
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Concrete Pad OPUS PID:
LATITUDE: 18° 21.6' N ( 18.36042) LONGITUDE: 64° 55.5' W ( -64.92453)
The bench mark is a disk set in the SEt corner of a 0.60 m (2.0 ft) x 0.60 m
(2.0 ft) x 0.30 m (1.0 ft) concrete pad off picnic shed #4 at Magens Bay Park,
18.83 m (61.8 ft) SSW of a 38.00 cm (15 inches) diameter wood pile at the SW
corner of a metal gate at the NE corner of shed #4, 16.74 m (54.9 ft) NW of the
centerline of a 6.00 m (19.7 ft) wide asphalt road, 10.79 m (35.4 ft) NNW of a
122.00 cm (48 in) diameter tree and 4.57 m (15.0 ft) WSW of a 1.25 m (4.1 ft) x
1.25 m (4.1 ft) x 1.00 m (3.3 ft) red brick fire pit.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 9751693 PUBLICATION DATE: 07/14/2021
Name: MAGENS BAY
VI
NOAA Chart: 25650 Latitude: 18° 22.0' N ( 18.36633)
USGS Quad: CENTRAL ST THOMAS Longitude: 64° 55.3' W ( -64.92211)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1693 D 2020
DESIGNATION: 975 1693 D
ALIAS: 1693 D
MONUMENTATION: Tidal Station disk VM#: 23545
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Concrete Footer OPUS PID:
LATITUDE: 18° 21.6' N ( 18.35967) LONGITUDE: 64° 55.5' W ( -64.92506)
The bench mark is a disk set in a concrete footer along the SE wall of a 6.75 m
(22.1 ft) x 23.5 m (77.1 ft) concrete bathhaouse in Magens Bay Park, 28.82 m
(94.6 ft) West of a 76.00 cm (30 in) diameter tree, 11.05 m (36.3 ft) NW of the
centerline of a 6.00 m (19.7 ft) wide asphalt road and 6.02 m (19.8 ft) SW of
the NE corner of a bathhouse.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 9751693 PUBLICATION DATE: 07/14/2021
Name: MAGENS BAY
VI
NOAA Chart: 25650 Latitude: 18° 22.0' N ( 18.36633)
USGS Quad: CENTRAL ST THOMAS Longitude: 64° 55.3' W ( -64.92211)
T I D A L D A T U M S
Tidal datums at MAGENS BAY based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: December 2020 - February 2021
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9755371 SAN JUAN, LA PUNTILLA, SAN JUAN BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.396
MEAN HIGH WATER MHW = 0.321
MEAN SEA LEVEL MSL = 0.180
MEAN TIDE LEVEL MTL = 0.179
Virgin Islands Vertical Datum of 2009 VIVD09 = 0.179
MEAN LOW WATER MLW = 0.038
MEAN LOWER LOW WATER MLLW = 0.000
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
GEN 0.929 0.608
1693 A 2020 2.352 2.031
1693 B 2020 2.144 1.823
1693 C 2020 1.837 1.516
1693 D 2020 1.720 1.399
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 9751693 PUBLICATION DATE: 07/14/2021
Name: MAGENS BAY
VI
NOAA Chart: 25650 Latitude: 18° 22.0' N ( 18.36633)
USGS Quad: CENTRAL ST THOMAS Longitude: 64° 55.3' W ( -64.92211)
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 any other fixed island datum.
This tide station location has a defined island datum (VIVD09). Island datums
are specific fixed geodetic datums whose elevation relationship to local MSL
and other tidal datums may not be consistent from one location to another.
Virgin Islands Vertical Datum of 2009 (VIVD09) is a fixed datum derived from
a simultaneous, least squares, minimum constraint adjustment of leveling
observations. Local mean sea level relative to the 1983-2001 National Tidal
Datum Epoch observed at tide stations 9751401 located at Lime Tree Bay,
St. Croix, 9751381 located at Lameshur Bay, St. John, and 9751639 located at
Charlotte Amalie, St Thomas was held fixed as the single initial constraint.
VIVD09 replaces all previous height system as the national standard geodetic
reference for heights in the Virgin Islands. Bench mark elevations relative
to VIVD09 are available from NGS through the World Wide Web at
National Geodetic Survey.
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 VIVD09 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have VIVD09 elevations.
The VIVD09 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, VIVD09 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from VIVD09 elevations listed for
each bench mark in the NGS database.