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National Ocean Service
Datums Page Page 1 of 5
Station ID: 9452434 PUBLICATION DATE: 06/21/2018
Name: TAIYASANKA HARBOR
AK
NOAA Chart: 17317 Latitude: 59° 18.1' N ( 59.30170)
USGS Quad: SKAGWAY (B-2) Longitude: 135° 25.7' W (-135.42800)
To reach the tidal bench marks, go to the entrance of Tiayasanka Harbor on the
NW shore which can be identified by a prominent rock outcropping made largely of
iron-streaked granite rock outcrop positioned between two separate 75 m (246 ft)
long sections of boulder-filled beach. The bench marks are located along the
beach in the general vicinity. The tide gauge was placed behind a large boulder,
25 m (82 ft) inland of the water's edge, and 8 m (26 ft) above the apparent high
water line.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 2434 C 1998
DESIGNATION: 945 2434 C
MONUMENTATION: Tidal Station disk VM#: 14046
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 59° 18.1' N ( 59.30170) LONGITUDE: 135° 25.7' W (-135.42800)
The primary bench mark is a disk set on a large flat section 5 m x 3 m (15 ft x
10 ft) of granite bedrock located on the front section of the outcropping, 46 m
(151 ft) SW (220 degrees magnetic) from bench mark 2434 B 1998, and 4 m (12 ft)
above the apparent high water line. Note: There is not a direct line of sight
between bench marks 2434 B 1998 and 2434 C 1998 due to the curvature of the
outcropping.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9452434 PUBLICATION DATE: 06/21/2018
Name: TAIYASANKA HARBOR
AK
NOAA Chart: 17317 Latitude: 59° 18.1' N ( 59.30170)
USGS Quad: SKAGWAY (B-2) Longitude: 135° 25.7' W (-135.42800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2434 A 1998
DESIGNATION: 945 2434 A
MONUMENTATION: Tidal Station disk VM#: 14044
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 59° 18.1' N ( 59.30170) LONGITUDE: 135° 25.7' W (-135.42800)
The bench mark is a disk set at approximately knee level at the lower end of a
very large (automobile-sized or larger), distinctive, polymorphous, red-coloured
rock located on the far eastern edge of the beach section directly to the east
of the outcropping, and is roughly 2 m (7 ft) above the apparent high water
line. Note: The bench mark may become covered during periods of extremely high
tide.
BENCH MARK STAMPING: 2434 B 1998
DESIGNATION: 945 2434 B
MONUMENTATION: Tidal Station disk VM#: 14045
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 59° 18.1' N ( 59.30170) LONGITUDE: 135° 25.7' W (-135.42800)
The bench mark is a disk set in gray colored granite bedrock, roughly two-third
of the way down from the high point of the outcropping which overlooks a portion
of the east beach section, located at the junction of the outcropping and the
beach section directly to the east, 51 m (167 ft) SW (200 degrees magnetic) from
bench mark 2434 A 1998.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9452434 PUBLICATION DATE: 06/21/2018
Name: TAIYASANKA HARBOR
AK
NOAA Chart: 17317 Latitude: 59° 18.1' N ( 59.30170)
USGS Quad: SKAGWAY (B-2) Longitude: 135° 25.7' W (-135.42800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2434 D 1998
DESIGNATION: 945 2434 D
MONUMENTATION: Tidal Station disk VM#: 14047
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Granite bedrock OPUS PID:
LATITUDE: 59° 18.1' N ( 59.30170) LONGITUDE: 135° 25.7' W (-135.42800)
The bench mark is a disk set on a narrow flat section of the granite bedrock on
the western portion of the outcropping overlooking the boulder-filled beach to
the west, near the junction of the outcropping and the beach section directly to
the west, 43 m (141 ft) NW (300 degrees magnetic) from bench mark 2434 C 1998.
Note: There is not a direct line of sight between bench marks 2434 C 1998 and
2434 D 1998 due to the curvature of the outcropping.
BENCH MARK STAMPING: 2434 E 1998
DESIGNATION: 945 2434 E
MONUMENTATION: Tidal Station disk VM#: 14048
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Granite bedrock OPUS PID:
LATITUDE: 59° 18.1' N ( 59.30170) LONGITUDE: 135° 25.7' W (-135.42800)
The bench mark is a disk set in the granite bedrock on the western portion of
the outcropping overlooking the boulder-filled beach to the west, near the
junction of the outcropping and the beach section directly to the west, 43 m
(141 ft) NW (295 degrees magnetic) from bench mark 2434 D 1998, in a direct line
of sight which follows the curvature of the outcropping.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9452434 PUBLICATION DATE: 06/21/2018
Name: TAIYASANKA HARBOR
AK
NOAA Chart: 17317 Latitude: 59° 18.1' N ( 59.30170)
USGS Quad: SKAGWAY (B-2) Longitude: 135° 25.7' W (-135.42800)
T I D A L D A T U M S
Tidal datums at TAIYASANKA HARBOR based on:
LENGTH OF SERIES: 30 DAYS
TIME PERIOD: Apr 28 1998 - May 27 1998
TIDAL EPOCH: 2012-2016
CONTROL TIDE STATION: 9452400 SKAGWAY, TAIYA INLET
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 5.103
MEAN HIGH WATER MHW = 4.810
MEAN SEA LEVEL MSL = 2.706
MEAN TIDE LEVEL MTL = 2.651
MEAN LOW WATER MLW = 0.493
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
2434 C 1998 8.786 3.977
2434 A 1998 7.194 2.384
2434 B 1998 8.379 3.570
2434 D 1998 8.481 3.671
2434 E 1998 9.148 4.339
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9452434 PUBLICATION DATE: 06/21/2018
Name: TAIYASANKA HARBOR
AK
NOAA Chart: 17317 Latitude: 59° 18.1' N ( 59.30170)
USGS Quad: SKAGWAY (B-2) Longitude: 135° 25.7' W (-135.42800)
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.