U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
Station ID: 9454673 PUBLICATION DATE: 04/06/2011
Name: PORT AUDREY
AK
NOAA Chart: 16700 Latitude: 60° 20.6' N ( 60.34330)
USGS Quad: Seward B-3 Longitude: 147° 46.1' W (-147.76800)
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 7 1966
MONUMENTATION: Survey disk VM#: 15191
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Set in sheer rock OPUS PID:
LATITUDE: 60° 20.6' N ( 60.34330) LONGITUDE: 147° 46.1' W (-147.76800)
The bench mark is a disk set in a sheer rock point, 27.74 m (91.0 ft) north of
bench mark 4673 5 1927, 160 m (525 ft) south of old ruins of Prince Packing
Company and west of the most prominent finger-like point extending in the middle
of the harbor.
BENCH MARK STAMPING: 4673 A 1998
DESIGNATION: 945 4673 A
MONUMENTATION: Survey disk VM#: 15187
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Set in low lying flat rock OPUS PID:
LATITUDE: 60° 20.6' N ( 60.34330) LONGITUDE: 147° 46.1' W (-147.76800)
The bench mark is a disk set in a low lying flat rock approximately 0.61 m x
0.91 m x 1.22 m (2.0 ft x 3.0 ft x 4.0 ft), located approximately 30.0 m (98.4
ft) north of bench mark NO 7 1966, 10 m to 20 m (32.8 ft to 65.6 ft) south of a
2.0 m (6.6 ft) wide, steep-loping, stream-bed that runs only during periods of
heavy rain, and 0.91 m (3.0 ft) above the apparent high water line.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
Station ID: 9454673 PUBLICATION DATE: 04/06/2011
Name: PORT AUDREY
AK
NOAA Chart: 16700 Latitude: 60° 20.6' N ( 60.34330)
USGS Quad: Seward B-3 Longitude: 147° 46.1' W (-147.76800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4673 5 1927
MONUMENTATION: Survey disk VM#: 15189
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Set in hard rock OPUS PID:
LATITUDE: 60° 20.6' N ( 60.34330) LONGITUDE: 147° 46.1' W (-147.76800)
The bench mark is a disk set in a hard rock about 18.29 m (60.0 ft) north of
bench mark NO 4 1927.
BENCH MARK STAMPING: 4673 6 1927
MONUMENTATION: Survey disk VM#: 15190
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Set in hard rock OPUS PID:
LATITUDE: 60° 20.6' N ( 60.34330) LONGITUDE: 147° 46.1' W (-147.76800)
The bench mark is a disk set in a hard rock under walk that extends from the NE
end of the wharf to store and Superintendent's dwelling. Short distance to
eastward is triangulation station standard reference mark.
BENCH MARK STAMPING: NO 8 1966
MONUMENTATION: Survey disk VM#: 15192
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Rock outrock OPUS PID:
LATITUDE: 60° 20.6' N ( 60.34330) LONGITUDE: 147° 46.1' W (-147.76800)
The bench mark is a disk set in a peak of rock outcrop between two small rock
points about 182.88 m (600.0 ft) south of old cannery ruins, 18.90 m (62.0 ft)
south of bench mark NO 7 1966, and 8.84 m (29.0 ft) north of bench mark 4673 5
1927.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
Station ID: 9454673 PUBLICATION DATE: 04/06/2011
Name: PORT AUDREY
AK
NOAA Chart: 16700 Latitude: 60° 20.6' N ( 60.34330)
USGS Quad: Seward B-3 Longitude: 147° 46.1' W (-147.76800)
T I D A L D A T U M S
Tidal datums at PORT AUDREY based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: August 1998 - August 1998
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 = 3.529
MEAN HIGH WATER MHW = 3.262
MEAN SEA LEVEL MSL = 1.884
MEAN TIDE LEVEL MTL = 1.850
MEAN LOW WATER MLW = 0.439
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 7 1966 4.934 1.672
4673 A 1998 3.876 0.614
4673 5 1927 6.361 3.099
4673 6 1927 5.386 2.124
NO 8 1966 5.395 2.133
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
Station ID: 9454673 PUBLICATION DATE: 04/06/2011
Name: PORT AUDREY
AK
NOAA Chart: 16700 Latitude: 60° 20.6' N ( 60.34330)
USGS Quad: Seward B-3 Longitude: 147° 46.1' W (-147.76800)
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.