U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 9466217 PUBLICATION DATE: 01/14/2011
Name: MEKORYUK, MEKORYUK RIVER ENTRANCE
AK
NOAA Chart: 16006 Latitude: 60° 25.0' N ( 60.41670)
USGS Quad: NUNIVAK ISLAND B-4 Longitude: 166° 10.0' W (-166.16700)
To reach the bench marks from the Mekoryuk runway, proceed 11.8 km (7.3 mi) ENE
on Airport Way through the village of Mekoryuk to where the road turns
approximately ninety degrees to the right, continue past the curve 0.3 km (0.2
mi) ESE to a short, unnamed access road on the right and the Mekoryuk City small
boat harbor. The bench marks are 0.3 km (0.2 mi) south of the harbor between
the grassy bluff and rock outcrop and the small rock island 0.3 km (0.2 mi) to
the south. The tide house was located on the south side of the grassy bluff and
the orifices were south of the rock point.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: TIDE 1951
DESIGNATION: 946 6217 TIDAL 1
MONUMENTATION: Topographic Station disk VM#: 19702
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 60° 23.1' N ( 60.38575) LONGITUDE: 166° 11.1' W (-166.18569)
The primary bench mark is set in a rock outcrop, 34.65 m (113.7 ft slope
distance) ENE of bench mark 946 6217 TIDAL 2, 31.40 m (103.0 ft) ESE of the
erosion prevention rock wall where it begins above the sand beach in the small
boat harbor, 18.35 m (60.2 ft) south of a 3/8" zinc anchor bolt projecting 6 cm
(0.2 ft) set in rock near approximate high water line, and 3.57 m (11.7 ft) SW
of the seaward edge of rocks.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9466217 PUBLICATION DATE: 01/14/2011
Name: MEKORYUK, MEKORYUK RIVER ENTRANCE
AK
NOAA Chart: 16006 Latitude: 60° 25.0' N ( 60.41670)
USGS Quad: NUNIVAK ISLAND B-4 Longitude: 166° 10.0' W (-166.16700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: MEKORYUK I95I
DESIGNATION: 946 6217 TIDAL 2
MONUMENTATION: Triangulation Station disk VM#: 19703
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete block OPUS PID:
LATITUDE: 60° 23.1' N ( 60.38569) LONGITUDE: 166° 11.2' W (-166.18628)
The bench mark is a disk set flush in a 0.34 m (1.12 ft) by 0.25 m (0.82 ft)
concrete block, 34.65 m (113.7 ft slope distance) WSW of bench mark 946 6217
TIDAL 1, 29.05 m (95.3 ft) SW of the NE corner of a white unnumbered house at
top of approximately 13 m (43 ft) high bluff, and 18.27 m (59.9 ft) east of the
SE corner of this same house and 0.14 m (0.05 ft) above ground.
BENCH MARK STAMPING: 6217 A 2010
DESIGNATION: 946 6217 A
MONUMENTATION: Tidal Station disk VM#: 19704
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 60° 23.1' N ( 60.38542) LONGITUDE: 166° 11.2' W (-166.18639)
The bench mark is set in a rock outcrop, 57.01 m (187.0 ft) NNE of bench mark
946 6217 B, 39.55 m (12.8 ft) SW of a 3/8" zinc anchor bolt projecting 6 cm (0.2
ft) set in rock near high water line, and 26.38 m (86.6 ft slope distance) east
of the NE corner of an unnumbered gray house.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9466217 PUBLICATION DATE: 01/14/2011
Name: MEKORYUK, MEKORYUK RIVER ENTRANCE
AK
NOAA Chart: 16006 Latitude: 60° 25.0' N ( 60.41670)
USGS Quad: NUNIVAK ISLAND B-4 Longitude: 166° 10.0' W (-166.16700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6217 B 2010
DESIGNATION: 946 6217 B
MONUMENTATION: Tidal Station disk VM#: 19705
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 60° 23.1' N ( 60.38500) LONGITUDE: 166° 11.2' W (-166.18706)
The bench mark is set in a rock outcrop, 57.01 m (187.0 ft) SSW of bench mark
946 6217 A, 19.64 m (64.4 ft slope distance) ESE of the SE corner of an
unnumbered gray wood house, and 4.15 m (13.6 ft) west of the seaward edge of
rocks.
BENCH MARK STAMPING: 6217 C 2010
DESIGNATION: 946 6217 C
MONUMENTATION: Tidal Station disk VM#: 19706
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID#: BBBZ39
LATITUDE: 60° 23.0' N ( 60.38353) LONGITUDE: 166° 11.2' W (-166.18736)
The bench mark is a disk set in a rock outcrop, 62.3 m (204.4 ft) north of a
large boulder near the approximate high waterline at the point projecting into
the channel, 18.1 m (59.4 ft slope distance) east of a 4 m (13.1 ft) high grassy
slope above the rock point, and 7.46 m (24.5 ft) SSW of seaward edge of rocks
near approximate high water line.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9466217 PUBLICATION DATE: 01/14/2011
Name: MEKORYUK, MEKORYUK RIVER ENTRANCE
AK
NOAA Chart: 16006 Latitude: 60° 25.0' N ( 60.41670)
USGS Quad: NUNIVAK ISLAND B-4 Longitude: 166° 10.0' W (-166.16700)
T I D A L D A T U M S
Tidal datums at MEKORYUK, MEKORYUK RIVER ENTRANCE based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: July 2010 - September 2010
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION:
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 2.323
MEAN HIGH WATER MHW = 2.149
MEAN SEA LEVEL MSL = 1.177
MEAN TIDE LEVEL MTL = 1.173
MEAN LOW WATER MLW = 0.196
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
TIDE 1951 3.649 1.500
MEKORYUK I95I 12.743 10.594
6217 A 2010 2.874 0.725
6217 B 2010 3.843 1.694
6217 C 2010 3.193 1.044
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9466217 PUBLICATION DATE: 01/14/2011
Name: MEKORYUK, MEKORYUK RIVER ENTRANCE
AK
NOAA Chart: 16006 Latitude: 60° 25.0' N ( 60.41670)
USGS Quad: NUNIVAK ISLAND B-4 Longitude: 166° 10.0' W (-166.16700)
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.