U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 11
Station ID: 9461710 PUBLICATION DATE: 10/06/2020
Name: ATKA, NAZAN BAY
NOAA Chart: 16490 Latitude: 52° 13.9' N ( 52.23200)
USGS Quad: ATKA (C-1) Longitude: 174° 10.4' W (-174.17260)
To reach the tide station from the airport, proceed 0.3 km (0.2 mi) south along
the main road to the first road intersection, turn right and proceed northerly
5.0 km (3.1 mi) to a 90 bend in the road, continue SE 0.5 km (0.3 mi) to the
head of the dock, turn right and proceed SW 61 m (200 ft) to the end of the dock
and the tide station on the left. The bench marks are along the gravel road and
on the dock.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 1710 B 2006
DESIGNATION: 946 1710 B
MONUMENTATION: Flange-encased Rod VM#: 18226
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBFL95
LATITUDE: 52° 14.0' N ( 52.23373) LONGITUDE: 174° 10.4' W (-174.17286)
The primary bench mark is set at the base of the bluff, 151 m (495 ft) NW of
bench mark 946 1710 D, 144 m (472 ft) ESE of bench mark 946 1710 E, 13.30 m
(46.3 ft) SE of a "Speed Limit 20" sign on the NE side of the road, and 2.41 m
(7.9 ft) NE of the north edge of a single lane gravel road which ends at the
dock. The datum point is set 0.12 m (0.4 ft) below grade, being the top of a
rounded off stainless steel rod with a punch mark driven 4.3 m (14 ft) to
refusal and encased in a 0.18 m (0.6 ft) diameter aluminum NGS Geodetic Control
Mark logo cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 11
Station ID: 9461710 PUBLICATION DATE: 10/06/2020
Name: ATKA, NAZAN BAY
NOAA Chart: 16490 Latitude: 52° 13.9' N ( 52.23200)
USGS Quad: ATKA (C-1) Longitude: 174° 10.4' W (-174.17260)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1710 A 2006
DESIGNATION: 946 1710 A
MONUMENTATION: Flange-encased Rod VM#: 18225
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBFL94
LATITUDE: 52° 13.9' N ( 52.23231) LONGITUDE: 174° 10.2' W (-174.17033)
The bench mark is set at the base of the bluff, 152 m (499 ft) ENE of bench mark
946 1710 C, 85.31 m (279.9 ft) ESE of bench mark 946 1710 D, 44.9 m (147.6 ft)
SE of the southeasterly most of two 1.98 m (6.5 ft) high red blank diamond
shaped street signs at the end of the road, 20.30 m (66.6 ft) NW of the west
face of a high boulder NW of the ATV trail, 10.39 m (34.1 ft) NE of the edge of
beach and grass line, and 5.00 m (16.4 ft) NE of the centerline of the ATV
trail. The datum point is set 9 cm (0.3 ft) below grade, being the top of a
rounded off stainless steel rod with a punch mark driven 3.7 m (12 ft) to
refusal and encased in a 0.18 m (0.6 ft) diameter aluminum NGS Geodetic Control
Mark logo cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 11
Station ID: 9461710 PUBLICATION DATE: 10/06/2020
Name: ATKA, NAZAN BAY
NOAA Chart: 16490 Latitude: 52° 13.9' N ( 52.23200)
USGS Quad: ATKA (C-1) Longitude: 174° 10.4' W (-174.17260)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1710 C 2006
DESIGNATION: 946 1710 C
MONUMENTATION: Tidal Station disk VM#: 18227
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 52° 13.9' N ( 52.23203) LONGITUDE: 174° 10.4' W (-174.17252)
The bench mark is set near the west edge of a 2.4 m x 1.5 m (8.0 ft x 5.0 ft)
steel plate on which the tide house sets, 152 m (499 ft) WSW of bench mark 946
1710 A, 113 m (371 ft) SW of bench mark 946 1710 D, 2.19 m (7.2 ft) SSW of the
east corner of the pier and the dock, 0.81 m (2.7 ft) WSW from the southerly
face of the 0.30 m x 0.30 m (1.0 ft x 1.0 ft) wooden bullrail, 0.20 m (0.7 ft)
SSE of the west edge of the steel plate, 0.05 m (0.2 ft) NNW of the NW face of
the tide house, and 0.04 m (0.1 ft) above the dock surface.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 11
Station ID: 9461710 PUBLICATION DATE: 10/06/2020
Name: ATKA, NAZAN BAY
NOAA Chart: 16490 Latitude: 52° 13.9' N ( 52.23200)
USGS Quad: ATKA (C-1) Longitude: 174° 10.4' W (-174.17260)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1710 D 2006
DESIGNATION: 946 1710 D
MONUMENTATION: Tidal Station disk VM#: 18228
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Concrete block OPUS PID:
LATITUDE: 52° 14.0' N ( 52.23274) LONGITUDE: 174° 10.3' W (-174.17135)
The bench mark is set flush near the north corner of a 3.05 m x 1.16 m x 0.21 m
(10.0 ft x 3.8 ft x 0.7 ft) high concrete block the western most of two concrete
blocks which support a blue connex which houses a generator, 151 m (495 ft) SE
of bench mark 946 1710 B, 113 m (371 ft) NE of bench mark 946 1710 C, 85.31 m
(279.9 ft) WNW of bench mark 946 1710 A, 5.44 m (17.9 ft) east from the NE'ly
corner of the pier and road, 1.80 m (5.9 ft) ENE from the center of a 0.61 m
(2.0 ft) diameter x 0.4 m (1.3 ft) high concrete memorial to Michael Snigaroff,
0.50 m (1.6 ft) north of the north corner of the connex, and 0.23 m (0.8 ft)
south of the north corner of the concrete block.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 11
Station ID: 9461710 PUBLICATION DATE: 10/06/2020
Name: ATKA, NAZAN BAY
NOAA Chart: 16490 Latitude: 52° 13.9' N ( 52.23200)
USGS Quad: ATKA (C-1) Longitude: 174° 10.4' W (-174.17260)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1710 E 2006
DESIGNATION: 946 1710 E
MONUMENTATION: Flange-encased Rod VM#: 18229
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBFL96
LATITUDE: 52° 14.1' N ( 52.23445) LONGITUDE: 174° 10.5' W (-174.17461)
The bench mark is set between the gravel road and the beach, 144 m (472 ft) WNW
of bench mark 946 1710 B, 85 m (279 ft) ESE of bench mark 946 1710 F, 36 m (118
ft) SE of a 0.60 m (2.0 ft) diameter metal culvert on the south side of the
road, and 3.60 m (11.8 ft) south of the southerly edge of a single lane gravel
road which ends at the dock. The datum point is set 0.10 m (0.3 ft) below grade,
being the top of a rounded off stainless steel rod with a punch mark driven 4.4
m (14.4 ft) to refusal and encased in a 0.18 m (0.6 ft) diameter aluminum NGS
Geodetic Control Mark logo cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 11
Station ID: 9461710 PUBLICATION DATE: 10/06/2020
Name: ATKA, NAZAN BAY
NOAA Chart: 16490 Latitude: 52° 13.9' N ( 52.23200)
USGS Quad: ATKA (C-1) Longitude: 174° 10.4' W (-174.17260)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1710 F 2006
DESIGNATION: 946 1710 F
MONUMENTATION: Flange-encased Rod VM#: 18230
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBFL97
LATITUDE: 52° 14.1' N ( 52.23489) LONGITUDE: 174° 10.5' W (-174.17562)
The bench mark is 244 m (801 ft) WNW of bench mark 946 1710 G, 85 m (279 ft) WNW
of bench mark 946 1710 E, 63 m (207 ft) east of the centerline of an ATV trail
which runs between a cabin and shed and forms a chord with the main road which
leads to the dock, 45 m (148 ft) NW of a 0.60 m (2.0 ft) diameter metal cuvert
on the south side of the road, and 2.99 m (9.8 ft) NNE of the north edge of the
gravel road. The datum point is set 0.12 m (0.4 ft) below grade, being the top
of a rounded off stainless steel rod with a punch mark driven 2.9 m (9.4 ft) to
refusal and encased in a 0.18 m (0.6 ft) diameter aluminum NGS Geodetic Control
Mark logo cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 11
Station ID: 9461710 PUBLICATION DATE: 10/06/2020
Name: ATKA, NAZAN BAY
NOAA Chart: 16490 Latitude: 52° 13.9' N ( 52.23200)
USGS Quad: ATKA (C-1) Longitude: 174° 10.4' W (-174.17260)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1710 G 2006
DESIGNATION: 946 1710 G
MONUMENTATION: Flange-encased Rod VM#: 18231
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBBC26
LATITUDE: 52° 14.1' N ( 52.23518) LONGITUDE: 174° 10.7' W (-174.17916)
The bench mark is set on top of a 1 m (3 ft) high grassy hill, 244 m (801 ft)
west of bench mark 946 1710 F, 168 m (551 ft) ENE of bench mark 946 1710 H, 27 m
(89 ft) NNE of the intersection of the centerline of the single lane gravel road
which ends at the dock and an ATV trail which runs between a house and shed and
forms a chord with the main road, and 15.51 m (50.9 ft) NNW of the west edge of
the road. The datum point is set 0.14 m (0.5 ft) below grade, being the top of a
rounded off stainless steel rod with a punch mark driven 3.7 m (12.0 ft) to
refusal and encased in a 0.18 m (0.6 ft) diameter aluminum NGS Geodetic Control
Mark logo cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 8 of 11
Station ID: 9461710 PUBLICATION DATE: 10/06/2020
Name: ATKA, NAZAN BAY
NOAA Chart: 16490 Latitude: 52° 13.9' N ( 52.23200)
USGS Quad: ATKA (C-1) Longitude: 174° 10.4' W (-174.17260)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1710 H 2006
DESIGNATION: 946 1710 H
MONUMENTATION: Flange-encased Rod VM#: 18232
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBFR86
LATITUDE: 52° 14.1' N ( 52.23461) LONGITUDE: 174° 10.9' W (-174.18144)
The bench mark is 168 m (551 ft) WSW of bench mark 946 1710 G, 168 m (551 ft)
ENE of bench mark 946 1710 J, 16.00 m (52.5 ft) NNE from the north corner of a
bridge on the single lane gravel road which ends at the dock, 9.69 m (31.8 ft)
NNW from the west edge of the gravel road, and 6.49 m (21.3 ft) ENE from the
centerline of an ATV trail. The bench mark is set 0.10 m (0.3 ft) below grade,
being the top of a rounded off stainless steel rod with a punch mark driven 4.9
m (16.0 ft) to refusal and encased in a 0.18 m (0.6 ft) diameter aluminum NGS
Geodetic Control Mark logo cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 9 of 11
Station ID: 9461710 PUBLICATION DATE: 10/06/2020
Name: ATKA, NAZAN BAY
NOAA Chart: 16490 Latitude: 52° 13.9' N ( 52.23200)
USGS Quad: ATKA (C-1) Longitude: 174° 10.4' W (-174.17260)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 1710 J 2006
DESIGNATION: 946 1710 J
MONUMENTATION: Tidal Station disk VM#: 18233
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBFR87
LATITUDE: 52° 14.0' N ( 52.23399) LONGITUDE: 174° 11.0' W (-174.18368)
The bench mark is 168 m (551 ft) WSW of bench mark 946 1710 H, 165 m (541 ft)
east of bench mark 946 1710 K, 30.51 m (100.1 ft) WSW of the south corner of a
bridge on the single lane gravel road which ends at the dock, 7.50 m (24.6 ft)
SSE of the SE edge of the gravel road, 4.11 m (13.5 ft) SE of the centerline of
an ATV trail, and 1 m (3 ft) below the top of the gravel road. The bench mark is
set 0.10 m (0.3 ft) below grade, being the top of a rounded off stainless steel
rod with a punch mark driven 2.8 m (9.3 ft) to refusal and encased in a 0.18 m
(0.6 ft) diameter aluminum NGS Geodetic Control Mark logo cover.
BENCH MARK STAMPING: 1710 K 2006
DESIGNATION: 946 1710 K
MONUMENTATION: Flange-encased Rod VM#: 18234
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBCR20
LATITUDE: 52° 14.0' N ( 52.23376) LONGITUDE: 174° 11.2' W (-174.18606)
The bench mark is 165 m (541 ft) west of bench mark 946 1710 J, 7.71 m (25.3 ft)
NNW of the NW edge of the the single lane gravel road which ends at the dock,
and 4 m (13 ft) east of a 3 m (10 ft) high grassy hill. The bench mark is set
0.15 m (0.5 ft) below grade, being the top of a rounded off stainless steel rod
with a punch mark driven 18.3 m (60 ft) to refusal and encased in a 0.18 m (0.6
ft) diameter aluminum NGS Geodetic Control Mark logo cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 10 of 11
Station ID: 9461710 PUBLICATION DATE: 10/06/2020
Name: ATKA, NAZAN BAY
NOAA Chart: 16490 Latitude: 52° 13.9' N ( 52.23200)
USGS Quad: ATKA (C-1) Longitude: 174° 10.4' W (-174.17260)
T I D A L D A T U M S
Tidal datums at ATKA, NAZAN BAY based on:
LENGTH OF SERIES: 8 YEARS
TIME PERIOD: 03/2008-02/2009, 12/2011-11/2014, 05/2015-04/2019
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9461380 ADAK ISLAND, SWEEPER COVE
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (01/18/2008) = 1.695
MEAN HIGHER HIGH WATER MHHW = 1.042
MEAN HIGH WATER MHW = 0.975
MEAN SEA LEVEL MSL = 0.599
MEAN TIDE LEVEL MTL = 0.566
North American Vertical Datum NAVD88 = 0.267
MEAN LOW WATER MLW = 0.157
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (12/13/2008) = -0.829
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
1710 B 2006 6.788 5.813
1710 A 2006 5.497 4.522
1710 C 2006 4.993 4.018
1710 D 2006 5.307 4.332
1710 E 2006 6.337 5.362
1710 F 2006 5.870 4.895
1710 G 2006 5.049 4.074
1710 H 2006 3.374 2.399
1710 J 2006 2.287 1.312
1710 K 2006 7.032 6.057
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 11 of 11
Station ID: 9461710 PUBLICATION DATE: 10/06/2020
Name: ATKA, NAZAN BAY
NOAA Chart: 16490 Latitude: 52° 13.9' N ( 52.23200)
USGS Quad: ATKA (C-1) Longitude: 174° 10.4' W (-174.17260)
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.