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National Ocean Service
Datums Page Page 1 of 8
Station ID: 9459450 PUBLICATION DATE: 10/06/2011
Name: SAND POINT, POPOF ISLAND
AK
NOAA Chart: 16553 Latitude: 55° 20.2' N ( 55.33669)
USGS Quad: PORT MOLLER (B-2) Longitude: 160° 30.1' W (-160.50200)
To reach the station from the airport proceed easterly on the only road ,3.4 km
(2.1 mi) to a gravel road on the left midway down a hill, turn left and proceed
northwesternly 0.8 km (0.5 mi) to the dry dock and a chain link fence, continue
westnorthwesternly through the chain link fence 1.0 km (0.6 mi) along the harbor
to the rip-rap and the road around the harbor, turn right and proceed northerly
0.3 km (0.2 mi) along the rip-rap road to the city dock. The tide staiton is
near the southern corner of the dock. The bench marks are along the road and the
vicinity of the boat harbor.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 9450 R 1991
DESIGNATION: 945 9450 R
MONUMENTATION: Tidal Station disk VM#: 4587
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete pier OPUS PID:
LATITUDE: 55° 19.9' N ( 55.33161) LONGITUDE: 160° 30.3' W (-160.50419)
The primary bench mark is a disk set in the most southerly corner of City Pier,
23.25 m (76.3 ft) SW of 945 9450 Y, 7.09 m (23.3 ft) NW of the centerline of the
gravel road to the City Pier, 4.46 m (14.6 ft) east of the NE corner of the tide
house, 0.80 m (2.6 ft) NE of SW edge of concrete pier, and 0.59 m (1.9 ft)
north of pier cleat.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 8
Station ID: 9459450 PUBLICATION DATE: 10/06/2011
Name: SAND POINT, POPOF ISLAND
AK
NOAA Chart: 16553 Latitude: 55° 20.2' N ( 55.33669)
USGS Quad: PORT MOLLER (B-2) Longitude: 160° 30.1' W (-160.50200)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9450 S 1991
DESIGNATION: 945 9450 S
MONUMENTATION: Tidal Station disk VM#: 4588
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete pier OPUS PID:
LATITUDE: 55° 19.9' N ( 55.33197) LONGITUDE: 160° 30.2' W (-160.50350)
The bench mark is a disk set in concrete in the NE corner of the City Pier,
36.30 m (119.1 ft) NE of bench mark 9459450 Y, 18.44 m (60.5 ft) SE of the NE
edge of the pier, 8.86 m (29.1 ft) north of the north edge of rip-rap on south
side of the gravel road, 8.18 m (26.8 ft) NE of the north corner of the 12.22 m
x 8.90 m (40.1 ft x 29.1 ft) blue warehouse, 0.90 m (3.0 ft) SW of a pier cleat,
and 0.49 m (1.6 ft) north of the southern concrete edge of the pier.
BENCH MARK STAMPING: 9450 T 1991
DESIGNATION: 945 9450 T
MONUMENTATION: Tidal Station disk VM#: 4589
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Boulder OPUS PID:
LATITUDE: 55° 19.9' N ( 55.33164) LONGITUDE: 160° 29.9' W (-160.49903)
The bench mark is a disk set in top of a 3.7 m x 2.4 m (12.1 ft x 7.9 ft) high
irregular shaped boulder along the north side of the road leading to the City
Pier, 101.50 m (333.0 ft) NE of the extended centerline of the causeway to the
City Pier, and 10.40 m (34.1 ft) NW of center of the road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 8
Station ID: 9459450 PUBLICATION DATE: 10/06/2011
Name: SAND POINT, POPOF ISLAND
AK
NOAA Chart: 16553 Latitude: 55° 20.2' N ( 55.33669)
USGS Quad: PORT MOLLER (B-2) Longitude: 160° 30.1' W (-160.50200)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9450 U 1991
DESIGNATION: 945 9450 U
MONUMENTATION: Tidal Station disk VM#: 4590
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete ramp OPUS PID:
LATITUDE: 55° 20.1' N ( 55.33478) LONGITUDE: 160° 29.8' W (-160.49608)
The bench mark is a disk set in the SE corner of a 16.02 m x 24.29 m (52.6 ft x
79.7 ft) concrete ramp for the "Marine Travelift" which is located at the north
section of the small boat harbor, 31.10 m (102.0 ft) south of the SE corner of a
building used for boat repair, 0.30 m (1.0 ft) NE of NE end of steel 10-inch
U-channel guard rail, and 0.15 m (0.5 ft) NW of easterly edge of concrete ramp.
BENCH MARK STAMPING:
DESIGNATION: 945 9450 SHEET PILE BOLT
MONUMENTATION: Bolt VM#: 4592
AGENCY: Commercial organization or private firmIDB PID#:
SETTING CLASSIFICATION: Sheet pile OPUS PID:
LATITUDE: 55° 20.0' N ( 55.33333) LONGITUDE: 160° 29.7' W (-160.49581)
The bench mark is a 0.75-inch diameter by 2.5-inch long horizontal bolt painted
orange which is turned upwards slightly - one of many similar bolts which secure
the wooden timbers to the top of the steel sheet piling cap, 21.55 m (70.7 ft)
north of where the sheet pile turns SW, 4.24 m (13.9 ft) north of the center of
a bollard, 0.36 m (1.2 ft) north of the northernmost point of a welded eyelet
which projects 0.10 m (0.3 ft) above the sheet pile cap, and 0.03 m (0.1 ft)
below the top of the sheet pile cap. Note: 2000 "BM" painted on face of sheet
pile just below bolt
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 8
Station ID: 9459450 PUBLICATION DATE: 10/06/2011
Name: SAND POINT, POPOF ISLAND
AK
NOAA Chart: 16553 Latitude: 55° 20.2' N ( 55.33669)
USGS Quad: PORT MOLLER (B-2) Longitude: 160° 30.1' W (-160.50200)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9450 V 1992
DESIGNATION: 945 9450 V
MONUMENTATION: Tidal Station disk VM#: 12593
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete causeway OPUS PID:
LATITUDE: 55° 19.9' N ( 55.33117) LONGITUDE: 160° 30.0' W (-160.50036)
The bench mark is a disk set in the cement which anchors the guard rail cable on
the northeastern corner of the gravel causeway leading to the City Pier, 3.70 m
(12.1 ft) north of cause way centerline, 1.34 m (4.4 ft) NE of the first 8-inch
x 8-inch x 3-foot high wooden guard rail post on the north side of the shore end
of gravel causeway, and 0.27 m (0.9 ft) east from the eye that the guard rail
cable is crimped to. NOTE: This mark will probably be buried under one to two
inches of dirt and gravel.
BENCH MARK STAMPING: 9450 X 1992
DESIGNATION: 945 9450 X
MONUMENTATION: Tidal Station disk VM#: 12595
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete vault OPUS PID:
LATITUDE: 55° 20.1' N ( 55.33536) LONGITUDE: 160° 29.8' W (-160.49744)
The bench mark is a disk set at the west side of New Harbor Caf beneath a 3.68
m x 1.81 m x 1.08 m (12.1 ft x 5.9 ft x 3.5 ft) high wooden deck which is
accessed through a 0.10 m x 0.10 m (0.3 ft x 0.3 ft) hinged hatch cover, 31.83 m
(104.4 ft) south of the southern end of the foot bridge, 5.16 m (16.9 ft) SE of
the western-most light pole in the harbor, and 0.10 m (0.3 ft) from the eastern
edge of a concrete electric vault which is elevated 0.09 m (0.1ft) above the
surrounding ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 8
Station ID: 9459450 PUBLICATION DATE: 10/06/2011
Name: SAND POINT, POPOF ISLAND
AK
NOAA Chart: 16553 Latitude: 55° 20.2' N ( 55.33669)
USGS Quad: PORT MOLLER (B-2) Longitude: 160° 30.1' W (-160.50200)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9450 Y 1997
DESIGNATION: 945 9450 Y
MONUMENTATION: Tidal Station disk VM#: 13743
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete pier OPUS PID:
LATITUDE: 55° 19.9' N ( 55.33181) LONGITUDE: 160° 30.2' W (-160.50392)
The bench mark is a disk set flush in concrete on the south side of the city
dock, 36.30 m (119.1 ft) SW of bench mark 9459450 S, 30.28 m (99.3 ft) SE of the
NW corner of the city dock, 23.26 m (76.3 ft) NE of bench mark 945 9450 R, 18.78
m (61.6 ft) ENE of the dock face, 16.16 m (53.0 ft) SW of the west corner of the
12.25 m x 8.90 m (40.1 ft x 29.1 ft) blue warehouse, 8.05 m (26.4 ft) north of
the northern edge of the riprap, and 0.15 m (0.5 ft) north of the southern edge
of dock.
BENCH MARK STAMPING: 1293-1 1984
DESIGNATION: 945 9450 TIDAL 1293-1
MONUMENTATION: Bench Mark disk VM#: 13744
AGENCY: US Army Corps of Engineers (USE) IDB PID#:
SETTING CLASSIFICATION: Concrete causeway OPUS PID#: BBBB50
LATITUDE: 55° 19.9' N ( 55.33203) LONGITUDE: 160° 30.2' W (-160.50258)
The bench mark is a disk set on the NE side of the gravel causeway on the north
side of the channel entrance to the harbor, 25.14 m (82.5 ft) north of the
center of a navigation aid base at the southern end of the northern break wall,
4.48 m (14.7 ft) NNE of centerline of causeway, 0.58 m (1.9 ft) NNE of wire
rope, 0.45 m (1.5 ft) SW of the SW edge of rip-rap on the NE side of the pier,
0.43 (1.4 ft) NNW from 7th post from southern end of break wall, 0.55 m (1.8 ft)
below road level, and 0.24 m (0.8 ft) below grade. NOTE: Mark may be buried up
to a foot.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 8
Station ID: 9459450 PUBLICATION DATE: 10/06/2011
Name: SAND POINT, POPOF ISLAND
AK
NOAA Chart: 16553 Latitude: 55° 20.2' N ( 55.33669)
USGS Quad: PORT MOLLER (B-2) Longitude: 160° 30.1' W (-160.50200)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9450 Z 2006
DESIGNATION: 945 9450 Z
MONUMENTATION: Tidal Station disk VM#: 18170
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete foundation OPUS PID:
LATITUDE: 55° 20.1' N ( 55.33567) LONGITUDE: 160° 29.8' W (-160.49656)
The bench mark is a disk set flush in concrete in the garage door of the
welder's shop at the harbor, 58.16 m (190.8 ft) NNE from the NE building corner
of the Harbor Cafe, 46.39 m (152.2 ft) WNW of the bottom of the stairs leading
from the Harbormaster's Office, 6.31 m (20.7 ft) SW from the east corner of the
welder's shop, 0.40 m (1.3 ft) NW from the front edge of the concrete pad, and
0.22 m (0.72 ft) NE from the west side of the garage door frame.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 8
Station ID: 9459450 PUBLICATION DATE: 10/06/2011
Name: SAND POINT, POPOF ISLAND
AK
NOAA Chart: 16553 Latitude: 55° 20.2' N ( 55.33669)
USGS Quad: PORT MOLLER (B-2) Longitude: 160° 30.1' W (-160.50200)
T I D A L D A T U M S
Tidal datums at SAND POINT, POPOF ISLAND based on:
LENGTH OF SERIES: 19 YEARS
TIME PERIOD: January 1983 - December 2001
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION:
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (12/31/1986) = 3.531
MEAN HIGHER HIGH WATER MHHW = 2.204
MEAN HIGH WATER MHW = 1.988
MEAN TIDE LEVEL MTL = 1.197
MEAN SEA LEVEL MSL = 1.181
MEAN LOW WATER MLW = 0.406
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (12/13/2008) = -1.164
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
9450 R 1991 4.593 2.605
9450 S 1991 4.589 2.601
9450 T 1991 3.847 1.859
9450 U 1991 4.401 2.413
945 9450 SHEET PILE BOLT 4.022 2.034
9450 V 1992 4.187 2.199
9450 X 1992 3.733 1.745
9450 Y 1997 4.567 2.579
1293-1 1984 3.580 1.592
9450 Z 2006 3.555 1.567
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 8 of 8
Station ID: 9459450 PUBLICATION DATE: 10/06/2011
Name: SAND POINT, POPOF ISLAND
AK
NOAA Chart: 16553 Latitude: 55° 20.2' N ( 55.33669)
USGS Quad: PORT MOLLER (B-2) Longitude: 160° 30.1' W (-160.50200)
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.