U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 9452400 PUBLICATION DATE: 02/16/2018
Name: SKAGWAY, TAIYA INLET
AK
NOAA Chart: 17317 Latitude: 59° 27.0' N ( 59.45000)
USGS Quad: SKAGWAY B-1 Longitude: 135° 19.6' W (-135.32700)
To reach the tidal bench marks from the U.S. Post Office/Bank of Alaska on 6th
and Broadway, proceed SW on Broadway for five blocks, turn NW on First Avenue
and proceed for one block, turn SE on Stage Street and enter the Cypress Anville
Ore Company (private property). Proceed down to the dock area. The tide gauge
is located on the pier adjacent to the walkway under a large ore elevator.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 11 1969
DESIGNATION: 945 2400 TIDAL 11
MONUMENTATION: Tidal Station disk VM#: 1202
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Bedrock OPUS PID:
LATITUDE: 59° 27.1' N ( 59.45214) LONGITUDE: 135° 18.9' W (-135.31536)
The primary bench mark is set flush with the surface of a projected segment of a
bedrock ledge, 48.80 m (160.0 ft) south of the White Pass and Yukon Railway
intersection of the spur line with the main line, 14.70 m (48.2 ft) NE of the
northern extent of a 1.20 m high (3.9 ft) chain-link fence, 2.74 m (9.0 ft) east
of the east rail of the spur line to the wharf, 1.82 m (6.0 ft) west of an
orange NOS witness post, and 0.36 m (1.2 ft) south of a 1-inch diameter anchor
bolt set in the same bedrock ledge.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 9452400 PUBLICATION DATE: 02/16/2018
Name: SKAGWAY, TAIYA INLET
AK
NOAA Chart: 17317 Latitude: 59° 27.0' N ( 59.45000)
USGS Quad: SKAGWAY B-1 Longitude: 135° 19.6' W (-135.32700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 8 1959
DESIGNATION: 945 2400 TIDAL 8
MONUMENTATION: Tidal Station disk VM#: 1207
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Boulder OPUS PID:
LATITUDE: 59° 27.0' N ( 59.45011) LONGITUDE: 135° 19.0' W (-135.31636)
The benchmark is a disk set in the NE end of an 2.44 m (8.0 ft) diameter
boulder, 18.59 m (61.0 ft) east of the White Pass and Yukon Railroad Dock Road
leading to the small boat harbor, 1.52 m (5.0 ft) south of a red 9.14 m x 30.48
m (30.0 ft x 100.0 ft) corrugated metal warehouse building, 0.85 m (2.8 ft) SE
of an orange NOS witness post, and 0.91 m (3.0 ft) above ground level.
BENCH MARK STAMPING: 2400 G 1997
DESIGNATION: 945 2400 G
MONUMENTATION: Tidal Station disk VM#: 13746
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: bedrock OPUS PID:
LATITUDE: 59° 27.2' N ( 59.45325) LONGITUDE: 135° 18.8' W (-135.31406)
The benchmark is set in a bedrock outcrop near the traihead of the Dewey Lakes
path along White Pass and Yukon Railway tracks, 24.38 m (80.0 ft) east of the
east end of a foot bridge that crosses Pullen Creek, 22.00 m (72.2 ft) NE of a
switch-box at the junction that switches the tracks to the railway station or
the cruise ship dock, 16.15 m (53.0 ft) east of the railroad tracks, 10.67 m
(35.0 ft) ESE of the Dewey Lakes trail sign, 3.05 m (10.0 ft) NNE of the trail,
and 0.30 m (1.0 ft) above grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 9452400 PUBLICATION DATE: 02/16/2018
Name: SKAGWAY, TAIYA INLET
AK
NOAA Chart: 17317 Latitude: 59° 27.0' N ( 59.45000)
USGS Quad: SKAGWAY B-1 Longitude: 135° 19.6' W (-135.32700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2400 J 1997
DESIGNATION: 945 2400 J
MONUMENTATION: Tidal Station disk VM#: 13748
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: bedrock OPUS PID:
LATITUDE: 59° 27.4' N ( 59.45606) LONGITUDE: 135° 18.6' W (-135.30986)
The benchmark is a disk set in a bedrock outcrop along White Pass and Yukon
Railway tracks NE of the junction that switches the tracks to the railway
station or the cruise ship dock, 91 m (299 ft) NE of extended north face of City
of Skagway Museum, 31.50 m (103.3 ft) south of the intersection of the service
road that parallels the railroad tracks and a gravel road that leads to Spring
Street, 3.57 m (11.7 ft) east of the railroad, and 0.91 m (3 ft) above ground
level.
BENCH MARK STAMPING: 2400 L 2012
DESIGNATION: 945 2400 L
MONUMENTATION: Tidal Station disk VM#: 20535
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Pier OPUS PID#: BBCT97
LATITUDE: 59° 27.0' N ( 59.45003) LONGITUDE: 135° 19.8' W (-135.32919)
The bench mark is disk set into the top of concrete on the west end of an
east/west running walkway to the cruise ship dock south of the tide station,
47.40 m (155 ft) west of the east face of the pier, 10.40 m (34 ft) east of the
west face of the pier, 8.30 m (34 ft) south of the north face of the pier, and
0.90 m (3.0 ft) north of the south face of pier.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 9452400 PUBLICATION DATE: 02/16/2018
Name: SKAGWAY, TAIYA INLET
AK
NOAA Chart: 17317 Latitude: 59° 27.0' N ( 59.45000)
USGS Quad: SKAGWAY B-1 Longitude: 135° 19.6' W (-135.32700)
T I D A L D A T U M S
Tidal datums at SKAGWAY, TAIYA INLET based on:
LENGTH OF SERIES: 18 YEARS
TIME PERIOD: Jan '83-Dec '95, Jan '97-Dec '01 & Jan '12-Dec '16
TIDAL EPOCH: 2012-2016
CONTROL TIDE STATION:
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (10/22/1945) = 8.175
MEAN HIGHER HIGH WATER MHHW = 5.101
MEAN HIGH WATER MHW = 4.795
MEAN SEA LEVEL MSL = 2.693
MEAN TIDE LEVEL MTL = 2.645
MEAN LOW WATER MLW = 0.495
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (12/14/2008) = -1.858
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
NO 11 1969 11.043 6.248
8 1959 10.766 5.971
2400 G 1997 12.746 7.951
2400 J 1997 11.445 6.650
2400 L 2012 9.065 4.270
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 9452400 PUBLICATION DATE: 02/16/2018
Name: SKAGWAY, TAIYA INLET
AK
NOAA Chart: 17317 Latitude: 59° 27.0' N ( 59.45000)
USGS Quad: SKAGWAY B-1 Longitude: 135° 19.6' W (-135.32700)
Foot Notes:
Certain geographic areas are experiencing rapid land movement due to uplift or
subsidence, which results in anomalous relative sea level trends compared to
most other coastal regions in the United States
(http://tidesandcurrents.noaa.gov/sltrends/index.shtml). In these areas, NOAA
has adopted a modified procedure for computing accepted tidal datums for the
National Water Level Observation Network (NWLON). The long-term control stations
in these areas have tidal datums reviewed approximately every 5 years, and if
they meet the criteria for an update, the 5-year period used for the modified
procedure will be listed in the Time Period section for the datums. The adoption
of this procedure was necessary to ensure that these tidal datums accurately
represent the existing stand of sea level relative to the land. A detailed
report explaining this modified procedure can be found in the publications
section of the CO-OPS Tides & Currents website at
http://tidesandcurrents.noaa.gov/pub.html.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 9452400 PUBLICATION DATE: 02/16/2018
Name: SKAGWAY, TAIYA INLET
AK
NOAA Chart: 17317 Latitude: 59° 27.0' N ( 59.45000)
USGS Quad: SKAGWAY B-1 Longitude: 135° 19.6' W (-135.32700)
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.