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National Ocean Service
Datums Page Page 1 of 5
Station ID: 9454794 PUBLICATION DATE: 04/06/2011
Name: APPLEGATE ISLAND
AK
NOAA Chart: 16013 Latitude: 60° 37.4' N ( 60.62330)
USGS Quad: SEWARD C-4 Longitude: 148° 9.9' W (-148.16500)
To reach the tidal bench marks, go to a side of a small islet which is one of a
group of three small islets laying west of Applegate Island at the southern
entrance to Culross Passage.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1
MONUMENTATION: Survey disk VM#: 13838
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 60° 37.4' N ( 60.62330) LONGITUDE: 148° 9.9' W (-148.16500)
The primary bench mark is a disk cemented in a drill hole, flush with a rock
surface in the western sloping (60 degrees) face of a prominent rocky point
leading northward near the the NE corner of a small island, the most easterly of
several islands at the southern entrance to Culross Passage, 244 m (800 ft) west
of Applegate Island, 6 m (20 ft) NE of a single large spruce tree, and about 15
m (50 ft) SSW of bench mark NO 4 1966.
BENCH MARK STAMPING: NO 3
MONUMENTATION: Survey disk VM#: 13842
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 60° 37.4' N ( 60.62330) LONGITUDE: 148° 9.9' W (-148.16500)
The bench mark is a disk set in a drill hole in a small rock ledge just below
the tree line on the southern end of the northern-most of a group of three
islands about 274 m (900 ft) west of Applegate Island at the southern entrance
to Culross Passage, about 76 m (250 ft) west of bench mark NO 1, about 9 m (30
ft) NE of the end of a low rock ledge running in the same direction, and about
at the apparent mean high water line.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9454794 PUBLICATION DATE: 04/06/2011
Name: APPLEGATE ISLAND
AK
NOAA Chart: 16013 Latitude: 60° 37.4' N ( 60.62330)
USGS Quad: SEWARD C-4 Longitude: 148° 9.9' W (-148.16500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 4 1966
MONUMENTATION: Survey disk VM#: 13843
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 60° 37.4' N ( 60.62330) LONGITUDE: 148° 9.9' W (-148.16500)
The bench mark is a disk cemented in a drill hole near the top of the
northern-most rock point of a island that is the most easterly of several
islands at the southern entrance to Culross Passage, about 244 m (800 ft) west
of Applegate Island, about 15 m (50 ft) NNE of bench mark NO 1, and about 1 m (2
ft) above apparent mean high water and the rocky point appears as a single rock
offshore from the island at mean high water.
BENCH MARK STAMPING: NO 5 1966
MONUMENTATION: Survey disk VM#: 13844
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 60° 37.4' N ( 60.62330) LONGITUDE: 148° 9.9' W (-148.16500)
The bench mark is a disk cemented in a drill hole in a rock depression along the
SE side of a small island which is the northern-most of a group of three islands
lying about 274 m (900 ft) west of Applegate Island at the southern entrance to
Culross Passage, about 1 m (3 ft) above the apparent mean high watre line and
about 15 m (50 ft) NE of bench mark NO 3.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9454794 PUBLICATION DATE: 04/06/2011
Name: APPLEGATE ISLAND
AK
NOAA Chart: 16013 Latitude: 60° 37.4' N ( 60.62330)
USGS Quad: SEWARD C-4 Longitude: 148° 9.9' W (-148.16500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4794 6 1997
MONUMENTATION: Tidal Station disk VM#: 13845
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Set in rock OPUS PID:
LATITUDE: 60° 37.4' N ( 60.62330) LONGITUDE: 148° 9.9' W (-148.16500)
The bench mark is a disk set flush in rock on the south side of a small islet
which is the western-most of a group of three small islets laying about 274 m
(900 ft) west of Applegate Island at the southern entrance to Culross Passage,
on the east side of the islet, just north of a lone spruce tree under an
overhanging branch, 50 m (164 ft) south of bench mark NO 3, 1.50 m (4.9 ft)
above the apparent high water line and 0.75 m (2.5 ft) below the vegetation
line.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9454794 PUBLICATION DATE: 04/06/2011
Name: APPLEGATE ISLAND
AK
NOAA Chart: 16013 Latitude: 60° 37.4' N ( 60.62330)
USGS Quad: SEWARD C-4 Longitude: 148° 9.9' W (-148.16500)
T I D A L D A T U M S
Tidal datums at APPLEGATE ISLAND based on:
LENGTH OF SERIES: 56 DAYS
TIME PERIOD: September 2 1997 - October 27 1997
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9454240 VALDEZ, PRINCE WILLIAM SOUND
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 3.689
MEAN HIGH WATER MHW = 3.410
MEAN SEA LEVEL MSL = 1.975
MEAN TIDE LEVEL MTL = 1.932
MEAN LOW WATER MLW = 0.454
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 3.595 0.186
NO 3 2.990 -0.419
NO 4 1966 2.934 -0.476
NO 5 1966 3.167 -0.242
4794 6 1997 4.853 1.443
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9454794 PUBLICATION DATE: 04/06/2011
Name: APPLEGATE ISLAND
AK
NOAA Chart: 16013 Latitude: 60° 37.4' N ( 60.62330)
USGS Quad: SEWARD C-4 Longitude: 148° 9.9' W (-148.16500)
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.