U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 9466012 PUBLICATION DATE: 03/20/2017
Name: EASTERN NUNIVAK ISLAND, BERING SEA
AK
NOAA Chart: 16006 Latitude: 60° 2.6' N ( 60.04294)
USGS Quad: NUNIVAK ISLAND A-2 Longitude: 165° 40.8' W (-165.68058)
To reach the tidal bench marks from the small boat harbor in Mekoryuk, proceed
north by boat 8 km (5.0 mi) around Cape Etolin, then proceed southeast 32 km
(19.9 mi) to Cape Manning, then proceed south along the east shore of Nunivak
Island for 26.5 km (16.5 mi) to a bay east of Twin Mountain. The bench marks
and tide gauge were located on a peninsula at the north end of the bay. The
legal description of the location is Seward meridian - Township 1 South - Range
95 West - Section 31.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 6012 A 2016
DESIGNATION: 946 6012 A
MONUMENTATION: Flange-encased Rod VM#: 22031
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: OPUS PID#: BBFG52
LATITUDE: 60° 2.6' N ( 60.04356) LONGITUDE: 165° 40.8' W (-165.67931)
The primary bench mark is a flange encased rod set at the narrowest point of the
peninsula at the N end of the bay, 21.70 m (71.2 ft) SSW of the tundra shoreline
cliff to the N, 21.54 m (70.7 ft) NNE of the tundra shoreline cliff to the
south, and 1.00 m (3.3 ft) S of a tundra mound with a dead bush. The datum
point is set 3.0 cm (1 inch) above ground, being the top of a stainless steel
rod driven 4.33 m (14.2 ft) to refusal, in a sleeve extending to a depth of 1.0
m (3.3 ft) and encased in a 7-inch NOS logo cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9466012 PUBLICATION DATE: 03/20/2017
Name: EASTERN NUNIVAK ISLAND, BERING SEA
AK
NOAA Chart: 16006 Latitude: 60° 2.6' N ( 60.04294)
USGS Quad: NUNIVAK ISLAND A-2 Longitude: 165° 40.8' W (-165.68058)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6012 B 2016
DESIGNATION: 946 6012 B
MONUMENTATION: Bench Mark disk VM#: 22032
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 60° 2.6' N ( 60.04253) LONGITUDE: 165° 40.7' W (-165.67842)
The bench mark is a disk set in a large boulder interlocked between other
boulders which are resting on bedrock, 11.9 m (39.0 ft) NW of the tundra
shoreline cliff, 3.15 m (10.3 ft) NE of the boulder cliff at high water, and
0.73 m (2.4 ft) NW of the edge of the boulder which the disk is set.
BENCH MARK STAMPING: 6012 C 2016
DESIGNATION: 946 6012 C
MONUMENTATION: Bench Mark disk VM#: 22033
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 60° 2.5' N ( 60.04242) LONGITUDE: 165° 40.6' W (-165.67742)
The bench mark is a disk set in a large boulder interlocked between other
boulders which are resting on bedrock, 8.65 m (28.4 ft) S of the tundra
shoreline cliff, 7.50 m (24.6 ft) NNW of the boulder cliff at high water, and
1.32 m (4.3 ft) S of the edge of the boulder on which the disk is set.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9466012 PUBLICATION DATE: 03/20/2017
Name: EASTERN NUNIVAK ISLAND, BERING SEA
AK
NOAA Chart: 16006 Latitude: 60° 2.6' N ( 60.04294)
USGS Quad: NUNIVAK ISLAND A-2 Longitude: 165° 40.8' W (-165.68058)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6012 D 2016
DESIGNATION: 946 6012 D
MONUMENTATION: Bench Mark disk VM#: 22034
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 60° 2.6' N ( 60.04278) LONGITUDE: 165° 40.6' W (-165.67689)
The bench mark is a disk set in a large boulder interlocked between other
boulders which are resting on bedrock, 13.42 m (44.0 ft) WSW of the boulder
cliff at high water, 13.35 m (43.8 ft) SE of where large boulders transition to
a rocky beach, 8.35 m (27.4 ft) ENE of the tundra cliff shoreline.
BENCH MARK STAMPING: 6012 E 2016
DESIGNATION: 946 6012 E
MONUMENTATION: Bench Mark disk VM#: 22035
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 60° 2.6' N ( 60.04336) LONGITUDE: 165° 40.6' W (-165.67658)
The bench mark is a disk set in a large boulder interlocked between other
boulders which are resting on bedrock, 13.7 m (44.9 ft) SE of the tundra
shoreline cliff, 6.85 m (22.5 ft) NW of the boulder cliff at high water, 1.44 m
(4.7 ft) NW of a 1 ft (0.3 m) ledge in the boulder which the disk is set, 0.40 m
(1.3 ft) SE of the edge of the boulder.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9466012 PUBLICATION DATE: 03/20/2017
Name: EASTERN NUNIVAK ISLAND, BERING SEA
AK
NOAA Chart: 16006 Latitude: 60° 2.6' N ( 60.04294)
USGS Quad: NUNIVAK ISLAND A-2 Longitude: 165° 40.8' W (-165.68058)
T I D A L D A T U M S
Tidal datums at EASTERN NUNIVAK ISLAND, BERING SEA based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: July 2016 - August 2016
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9463502 PORT MOLLER, BRISTOL BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 2.214
MEAN HIGH WATER MHW = 2.079
MEAN SEA LEVEL MSL = 1.151
MEAN TIDE LEVEL MTL = 1.148
MEAN LOW WATER MLW = 0.216
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
6012 A 2016 6.968 4.889
6012 B 2016 3.230 1.151
6012 C 2016 3.931 1.852
6012 D 2016 4.017 1.938
6012 E 2016 3.411 1.332
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9466012 PUBLICATION DATE: 03/20/2017
Name: EASTERN NUNIVAK ISLAND, BERING SEA
AK
NOAA Chart: 16006 Latitude: 60° 2.6' N ( 60.04294)
USGS Quad: NUNIVAK ISLAND A-2 Longitude: 165° 40.8' W (-165.68058)
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.