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National Ocean Service
Datums Page Page 1 of 5
Station ID: 9451037 PUBLICATION DATE: 08/03/2004
Name: VILLAGE ROCK
AK
NOAA Chart: 17385 Latitude: 56° 13.2' N ( 56.22000)
USGS Quad: PETERSBURG (A-1) Longitude: 132° 17.8' W (-132.29700)
To reach the tidal marks from Wrangell Harbor via boat, proceed 28 km (15 nm)
south through Zimovia Strait until abeam of Turn Island, then proceed 4 km (2
nm) SE to the Village Island Light 13, a green 4-second flashing light located
on a small islet marking the NE extent of the Village Islands. Then proceed 0.9
km (0.5 nm) NE to a ruined wood cabin. The bench marks are located in the
vicinity of the cabin. The tide gauge was located at the western base of the
cabin.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 1037 A 2001
DESIGNATION: 945 1037 A
MONUMENTATION: Tidal Station disk VM#: 16491
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Boulder OPUS PID:
LATITUDE: 56° 13.3' N ( 56.22170) LONGITUDE: 132° 18.0' W (-132.30000)
The primary bench mark is a disk set into a flat topped 1 m x 1 m (4 ft x 4 ft)
wide boulder, 7 m (24 ft) east of a stream filled with boulders, NW (336 degrees
magnetic) from the Village Rock red day beacon 12, 5 m (16 ft) south of the
tree line, and 2 m (7 ft) NW of the apparent high water line.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9451037 PUBLICATION DATE: 08/03/2004
Name: VILLAGE ROCK
AK
NOAA Chart: 17385 Latitude: 56° 13.2' N ( 56.22000)
USGS Quad: PETERSBURG (A-1) Longitude: 132° 17.8' W (-132.29700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1037 B 2001
DESIGNATION: 945 1037 B
MONUMENTATION: Tidal Station disk VM#: 16492
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Boulder OPUS PID:
LATITUDE: 56° 13.3' N ( 56.22170) LONGITUDE: 132° 18.0' W (-132.30000)
The bench mark is a disk set into the center of a 1 m x 1 m (2 ft x 3 ft) moss
covered rock, 20.70 m (67.9 ft) east of bench mark 1037 C 2001, NNW (341 degrees
magnetic) from the Village Rock red day beacon 12, 6 m (20 ft) NE of the
apparent high water line, and flush with the surrounding ground at the base of
the tree line.
BENCH MARK STAMPING: 1037 C 2001
DESIGNATION: 945 1037 C
MONUMENTATION: Tidal Station disk VM#: 16493
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Boulder OPUS PID:
LATITUDE: 56° 13.3' N ( 56.22170) LONGITUDE: 132° 18.0' W (-132.30000)
The bench mark is a disk set into a boulder, 56 m (184 ft) east of Thomas Lake
trail head, NNW (340 degrees magnetic) from the Village Rock red day beacon 12,
SE (121 degrees magnetic) from the green day beacon 15, 20.70 m (67.9 ft) west
of bench mark 1037 B 2001, 4 m (14 ft) NW of the apparent high water line, and
1.50 m (4.9 ft) seaward of the tree line.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9451037 PUBLICATION DATE: 08/03/2004
Name: VILLAGE ROCK
AK
NOAA Chart: 17385 Latitude: 56° 13.2' N ( 56.22000)
USGS Quad: PETERSBURG (A-1) Longitude: 132° 17.8' W (-132.29700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1037 D 2001
DESIGNATION: 945 1037 D
MONUMENTATION: Tidal Station disk VM#: 16494
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Boulder OPUS PID:
LATITUDE: 56° 13.3' N ( 56.22170) LONGITUDE: 132° 18.0' W (-132.30000)
The bench mark is a disk set in a 1 m x 1 m (4 ft x 4 ft) rock at the tree line,
18 m (60 ft) east of log cabin ruins, 10 m (32 ft) SW of Thomas Lake trail head,
NNW (350 degrees magnetic) from the Village Rock red day beacon 12, and SE (130
degrees magnetic) from the green day beacon 15, and 9 m (28 ft) NW of the
apparent high water line.
BENCH MARK STAMPING: 1037 E 2001
DESIGNATION: 945 1037 E
MONUMENTATION: Tidal Station disk VM#: 16495
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Boulder OPUS PID:
LATITUDE: 56° 13.3' N ( 56.22170) LONGITUDE: 132° 18.0' W (-132.30000)
The bench mark is a disk set in a 1 m x 1 m (2 ft x 3 ft) rock, seaward of a
large boulder that is located at the tree line, NNW (351 degrees magnetic) from
the Village Rock red day beacon 12, SE (129 degrees magnetic) from the green day
beacon 15, 37 m (120 ft) SW from cabin ruins, 5 m (16 ft) from tree line, and 1
m (3 ft) from the apparent high water line.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9451037 PUBLICATION DATE: 08/03/2004
Name: VILLAGE ROCK
AK
NOAA Chart: 17385 Latitude: 56° 13.2' N ( 56.22000)
USGS Quad: PETERSBURG (A-1) Longitude: 132° 17.8' W (-132.29700)
T I D A L D A T U M S
Tidal datums at VILLAGE ROCK based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: April 2001 - May 2001
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9450460 KETCHIKAN, TONGASS NARROWS
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 4.915
MEAN HIGH WATER MHW = 4.655
MEAN TIDE LEVEL MTL = 2.559
MEAN SEA LEVEL MSL = 2.549
MEAN LOW WATER MLW = 0.463
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
1037 A 2001 5.715 1.061
1037 B 2001 6.122 1.468
1037 C 2001 5.740 1.085
1037 D 2001 6.242 1.587
1037 E 2001 5.586 0.931
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9451037 PUBLICATION DATE: 08/03/2004
Name: VILLAGE ROCK
AK
NOAA Chart: 17385 Latitude: 56° 13.2' N ( 56.22000)
USGS Quad: PETERSBURG (A-1) Longitude: 132° 17.8' W (-132.29700)
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.