U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 9451409 PUBLICATION DATE: 03/04/2009
Name: MOUNTAIN POINT, (CANNERY)
AK
NOAA Chart: 17375 Latitude: 56° 44.4' N ( 56.74000)
USGS Quad: PETERSBURG (C-3) Longitude: 132° 57.5' W (-132.95806)
To reach the tidal bench marks from Petersburg, proceed SSE by boat along
Wrangell Narrows for 10 km (5.4 nm) to Mountain Point on Kupreanof Island. The
bench marks are located in the vicinity north of Mountain Point. The tide gage
and staff were located north of Maintain Point along a cove which contains the
mouth of a small stream.
T I D A L B E N C H M A R K S
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 9451409 PUBLICATION DATE: 03/04/2009
Name: MOUNTAIN POINT, (CANNERY)
AK
NOAA Chart: 17375 Latitude: 56° 44.4' N ( 56.74000)
USGS Quad: PETERSBURG (C-3) Longitude: 132° 57.5' W (-132.95806)
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING:
DESIGNATION: SIGNAL 22
ALIAS: NO STAMPING 1
MONUMENTATION: Bolt VM#: 9378
AGENCY: US Army Corps of Engineers (USE) IDB PID#: TT8845
SETTING CLASSIFICATION: Rock bluff OPUS PID:
LATITUDE: 56° 44.4' N ( 56.74000) LONGITUDE: 132° 57.6' W (-132.96000)
The primary bench mark is a brass bolt without head set in the rock bluffs north
of Mountain Point along the west shore of Wrangell Narrows, and 17 m (55 ft) ESE
of bench mark 1409 A 1978.
BENCH MARK STAMPING: 1409 A 1978
DESIGNATION: 945 1409 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 9375
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcropping OPUS PID:
LATITUDE: 56° 44.3' N ( 56.73830) LONGITUDE: 132° 57.4' W (-132.95700)
The bench mark is a disk set in the top of a 1 m (4 ft) high north/south
trending rock outcrop north of Mountain Point, and 9 m (30 ft) SSW of the cove
located north of Mountain Point.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 9451409 PUBLICATION DATE: 03/04/2009
Name: MOUNTAIN POINT, (CANNERY)
AK
NOAA Chart: 17375 Latitude: 56° 44.4' N ( 56.74000)
USGS Quad: PETERSBURG (C-3) Longitude: 132° 57.5' W (-132.95806)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1409 B 1978
DESIGNATION: 945 1409 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 9376
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Granite boulder OPUS PID:
LATITUDE: 56° 44.3' N ( 56.73830) LONGITUDE: 132° 57.4' W (-132.95700)
The bench mark is a disk set in the top of a 1 m x 2 m x 1 m (3 ft x 5 ft x 3
ft) granite boulder west of the cove located north of Mountain Point, 38 m (125
ft) NNW of bench mark 1409 A 1978, and 15 m (50 ft) NW of the mouth of the small
stream that empties into the cove.
BENCH MARK STAMPING: 1409 C 1978
DESIGNATION: 945 1409 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 9377
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock ledge OPUS PID:
LATITUDE: 56° 44.3' N ( 56.73830) LONGITUDE: 132° 57.4' W (-132.95700)
The bench mark is a disk set in the top of a smooth rock ledge that runs
parallel to Wrangell Narrows between Mountain Point and the cove located north
of Mountain Point, and 47 m (155 ft) SW of bench mark SIGNAL 22 RM (NO STAMPING
2).
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 9451409 PUBLICATION DATE: 03/04/2009
Name: MOUNTAIN POINT, (CANNERY)
AK
NOAA Chart: 17375 Latitude: 56° 44.4' N ( 56.74000)
USGS Quad: PETERSBURG (C-3) Longitude: 132° 57.5' W (-132.95806)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: SIGNAL 22 RM
ALIAS: NO STAMPING 2
MONUMENTATION: Reference Mark disk VM#: 9379
AGENCY: US Army Corps of Engineers (USE) IDB PID#: AE6469
SETTING CLASSIFICATION: Rock ledge OPUS PID:
LATITUDE: 56° 44.3' N ( 56.73830) LONGITUDE: 132° 57.4' W (-132.95700)
The bench mark is a disk set in a rock ledge along the western shore of Wrangell
Narrows, and 5.21 m (17.1 ft) south of bench mark SIGNAL 22 (NO STAMPING 1).
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 9451409 PUBLICATION DATE: 03/04/2009
Name: MOUNTAIN POINT, (CANNERY)
AK
NOAA Chart: 17375 Latitude: 56° 44.4' N ( 56.74000)
USGS Quad: PETERSBURG (C-3) Longitude: 132° 57.5' W (-132.95806)
T I D A L D A T U M S
Tidal datums at MOUNTAIN POINT, (CANNERY) based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: October 1978 - October 1978
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 = 5.028
MEAN HIGH WATER MHW = 4.735
MEAN SEA LEVEL MSL = 2.594
MEAN TIDE LEVEL MTL = 2.592
MEAN LOW WATER MLW = 0.449
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
SIGNAL 22 5.491 0.756
1409 A 1978 6.001 1.266
1409 B 1978 7.129 2.394
1409 C 1978 5.310 0.575
SIGNAL 22 RM 5.925 1.190
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 9451409 PUBLICATION DATE: 03/04/2009
Name: MOUNTAIN POINT, (CANNERY)
AK
NOAA Chart: 17375 Latitude: 56° 44.4' N ( 56.74000)
USGS Quad: PETERSBURG (C-3) Longitude: 132° 57.5' W (-132.95806)
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.