U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 9465261 PUBLICATION DATE: 12/13/2012
Name: CLARKS POINT, NUSHAGAK BAY
AK
NOAA Chart: 16322 Latitude: 58° 50.9' N ( 58.84830)
USGS Quad: NUSHAGAK BAY D-2 Longitude: 158° 33.1' W (-158.55200)
To reach the tidal bench marks from the Clarks Point airport, turn right west on
unnamed gravel road for 0.44 km (0.27 mi) to T with unnamed gravel road,
proceed right and continue west down the bluff for 1.15 km (0.71 mi) to the
gravel road that parallels the beach, turn right and continue north for 0.56 km
(0.34 mi) across the old gravel runway and onto the Trident Seafoods property.
The bench marks are located amongst the abandoned buildings. The tide gauge is
located at the southern corner of the blue metal building on the old wooden
cannery dock at the northern most end of Clarks Point.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 5 RESET 1949
DESIGNATION: 946 5261 TIDAL 5 RESET
MONUMENTATION: Tidal Station disk VM#: 20562
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Iron pipe OPUS PID:
LATITUDE: 58° 50.6' N ( 58.84294) LONGITUDE: 158° 33.2' W (-158.55358)
The primary bench mark is a disk welded to the top of a 2 -inch
galvanized-iron pipe set in the grass between two abandoned buildings, 15.77 m
(51.7 ft) SSW of the SE corner of a 2-story building with metal siding, 13.86 m
(45.5 ft) ESE of the NW corner of a 2-story building with wood siding, 0.56 m
(1.8 ft) west of the NW corner of the old abandoned mess hall and 0.11 m (0.4
ft) above grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9465261 PUBLICATION DATE: 12/13/2012
Name: CLARKS POINT, NUSHAGAK BAY
AK
NOAA Chart: 16322 Latitude: 58° 50.9' N ( 58.84830)
USGS Quad: NUSHAGAK BAY D-2 Longitude: 158° 33.1' W (-158.55200)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: CLARK 1947 AZIMUTH
DESIGNATION: CLARK AZ MK
MONUMENTATION: Reference Mark disk VM#: 20563
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: UV7281
SETTING CLASSIFICATION: Iron pipe OPUS PID#: UV7281
LATITUDE: 58° 50.6' N ( 58.84317) LONGITUDE: 158° 33.3' W (-158.55453)
The bench mark is a disk welded to the top of a 2 -inch galvanized-iron pipe
with a concrete collar set in the grass, 40.88 m (134.1 ft) north of a three log
dolphin with a large anchor at its base and near the abandoned Office Building,
30.48 m (100.0 ft) NNW of the NW corner of the abandoned Office Building, and
15.58 m (51.1 ft) SW of the NW corner of a blue building along the oceanfront
and set 0.04 m (0.1 ft) below grade.
BENCH MARK STAMPING: NO 4 1947
DESIGNATION: 946 5261 TIDAL 4
MONUMENTATION: Tidal Station disk VM#: 20565
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Iron pipe OPUS PID:
LATITUDE: 58° 50.6' N ( 58.84319) LONGITUDE: 158° 33.3' W (-158.55450)
The bench mark is a disk welded to the top of a 2 -inch galvanized-iron pipe
with a concrete collar set in the ground below a porch attached to the abandoned
building directly south of an old wooden dock that goes dry at low tide, 21.39 m
(70.2 ft) south of a fire valve pipe surrounded by 2 red bollards, 20.83 m (68.3
ft) SE of the beginning of the wood ramp leading to the old dock, 1.24 m (4.1
ft) west of the NE corner of the porch, 0.78 m (2.6 ft) NNE of the abandoned
building s NE corner and 0.20 m (0.7 ft) above grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9465261 PUBLICATION DATE: 12/13/2012
Name: CLARKS POINT, NUSHAGAK BAY
AK
NOAA Chart: 16322 Latitude: 58° 50.9' N ( 58.84830)
USGS Quad: NUSHAGAK BAY D-2 Longitude: 158° 33.1' W (-158.55200)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 11 1949
DESIGNATION: 946 5261 TIDAL 11
MONUMENTATION: Tidal Station disk VM#: 20566
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete pad OPUS PID:
LATITUDE: 58° 50.6' N ( 58.84264) LONGITUDE: 158° 33.2' W (-158.55397)
The bench mark is a disk set in the NE corner of an overgrown concrete pad,
20.67 m (67.8 ft) NE of the NE corner of a 5 m x 5 m (16 ft x 16 ft) shack that
is SE of the abandoned Office Building, 14.86 m (48.8 ft) SE of the SE corner of
the abandoned Office Building, and 14.52 m (47.6 ft) west of a radio tower.
BENCH MARK STAMPING: 5621 B 2012
DESIGNATION: 946 5621 B
MONUMENTATION: Flange-encased Rod VM#: 20568
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID:
LATITUDE: 58° 50.5' N ( 58.84217) LONGITUDE: 158° 33.3' W (-158.55469)
The bench mark is a stainless steel rod set 39.12 m (128.3 ft) SSW of the south
corner of a blue wood shed, 16.46 m (54.0 ft) south of 14-inch diameter shut-off
valve labeled Crane , and 2.72 m (8.9 ft) ENE of the east corner of a 5.0 m x
4.3 m (16.4 ft x 14.1 ft) blue metal shack. The datum point is set 9 cm (0.3
ft) below the ground, being the top of a stainless steel rod driven 21.9 m (72
ft) to refusal, and encased in a 5-inch NOS logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9465261 PUBLICATION DATE: 12/13/2012
Name: CLARKS POINT, NUSHAGAK BAY
AK
NOAA Chart: 16322 Latitude: 58° 50.9' N ( 58.84830)
USGS Quad: NUSHAGAK BAY D-2 Longitude: 158° 33.1' W (-158.55200)
T I D A L D A T U M S
Tidal datums at CLARKS POINT, NUSHAGAK BAY based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: June 2012 - July 2012
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 = 6.301
MEAN HIGH WATER MHW = 5.757
MEAN SEA LEVEL MSL = 3.343
MEAN TIDE LEVEL MTL = 3.285
MEAN LOW WATER MLW = 0.812
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
NO 5 RESET 1949 7.404 1.647
CLARK 1947 AZIMUTH 8.265 2.508
NO 4 1947 7.786 2.029
NO 11 1949 7.544 1.787
5621 B 2012 7.156 1.399
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9465261 PUBLICATION DATE: 12/13/2012
Name: CLARKS POINT, NUSHAGAK BAY
AK
NOAA Chart: 16322 Latitude: 58° 50.9' N ( 58.84830)
USGS Quad: NUSHAGAK BAY D-2 Longitude: 158° 33.1' W (-158.55200)
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.