U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 9469237 PUBLICATION DATE: 11/16/2010
Name: POINT SPENCER, PORT CLARENCE
AK
NOAA Chart: 16204 Latitude: 65° 15.4' N ( 65.25670)
USGS Quad: TELLER (B-4) Longitude: 166° 50.8' W (-166.84700)
To reach the bench marks from the Nome airport, proceed east on Seppala Drive to
the three way intersection with Seppala Drive, FAA Road and Center Creek Road.
Then proceed NE on Center Creek Road to the intersection with Little Creek Road,
then proceed east to the intersection with the Nome-Teller Highway, follow the
highway as it starts to head NNW and turns into the Bob Blodgett Highway, then
proceed 104 km (65 mi) NNW to Teller, from Teller by boat head 23 km (14 mi)
west to Point Spencer. Alternate method: To reach the bench marks by plane from
the Nome airport fly 109 km (68 mi) NW to the Point Spencer USCG airstrip. The
bench marks are located approximately 0.8 km (0.5 mi) ENE from the south end of
the gravel runway. The bubbler orifices were located in the vicinity of the
bench marksoi.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1950
DESIGNATION: 945 9237 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 18003
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete block OPUS PID:
LATITUDE: 65° 15.3' N ( 65.25578) LONGITUDE: 166° 51.0' W (-166.85011)
The primary bench mark is a disk set in a 0.58 m x 0.58 m (1.9 ft x 1.9 ft)
concrete block that is the remains of the NE footing for a 10 m (33 ft) tall
tower located on the east side of the spit and on the west side of Port
Clarence, 2.1 km (1.3 mi) south of Point Spencer, and 0.58 m (1.9 ft) above the
ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 9469237 PUBLICATION DATE: 11/16/2010
Name: POINT SPENCER, PORT CLARENCE
AK
NOAA Chart: 16204 Latitude: 65° 15.4' N ( 65.25670)
USGS Quad: TELLER (B-4) Longitude: 166° 50.8' W (-166.84700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 2 1950
DESIGNATION: 945 9237 TIDAL 2
MONUMENTATION: Tidal Station disk VM#: 18004
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete block OPUS PID:
LATITUDE: 65° 15.3' N ( 65.25572) LONGITUDE: 166° 51.0' W (-166.85014)
The bench mark is a disk set in the 0.58 m x 0.58 m (1.9 ft x 1.9 ft) concrete
block that is the remains of the SE footing for a 10 m (33 ft) tall tower
located on the east side of the spit and on the west side of Port Clarence, 2.1
km (1.3 mi) south of Point Spencer, 35 m (114 ft) west of apparent MHW, and 0.58
m (1.9 ft) above ground.
BENCH MARK STAMPING: NO 3 1950
DESIGNATION: 945 9237 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 18005
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete block OPUS PID:
LATITUDE: 65° 15.3' N ( 65.25578) LONGITUDE: 166° 51.0' W (-166.85022)
The bench mark is a disk set in the 0.58 m x 0.58 m (1.9 ft x 1.9 ft) concrete
block that is the remains of the NW footing for a 10 m (33 ft) tall tower
located on the east side of the spit and on the west side of Port Clarence, 2.1
km (1.3 mi) south of Point Spencer, and 35 m (114 ft) west of apparent MHW.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 9469237 PUBLICATION DATE: 11/16/2010
Name: POINT SPENCER, PORT CLARENCE
AK
NOAA Chart: 16204 Latitude: 65° 15.4' N ( 65.25670)
USGS Quad: TELLER (B-4) Longitude: 166° 50.8' W (-166.84700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9237 A 2005
DESIGNATION: 945 9237 A
MONUMENTATION: Tidal Station disk VM#: 18006
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete block OPUS PID#: BBCC44
LATITUDE: 65° 15.5' N ( 65.25831) LONGITUDE: 166° 50.8' W (-166.84733)
The bench mark is a disk set in the northern corner of a 1.49 m x 1.49 m (4.9 ft
x 4.9 ft) tilted concrete block on the eastern beach of Point Spencer, 250 m
(820 ft) north of the remains of a 10 m (33 ft) tall tower, 25 m (82 ft) west of
apparent MHW, and 0.58 m (1.9 ft) above ground. Note: The top of the disk is
tilted, leveled to the top of the high point of the disk.
BENCH MARK STAMPING: OBM RM 2 1945
DESIGNATION: 946 9237 OBM RM 2
MONUMENTATION: Tidal Station disk VM#: 18007
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 65° 15.8' N ( 65.26406) LONGITUDE: 166° 50.5' W (-166.84189)
The bench mark is a disk set in a gravel section on the east side of the Port
Clarence spit, 1.4 km (0.9 mi) south of Point Spencer and 80 m (262 ft) from
apparent MHW. The bench mark is crimped to a stainless steel rod driven to an
unspecified depth.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 9469237 PUBLICATION DATE: 11/16/2010
Name: POINT SPENCER, PORT CLARENCE
AK
NOAA Chart: 16204 Latitude: 65° 15.4' N ( 65.25670)
USGS Quad: TELLER (B-4) Longitude: 166° 50.8' W (-166.84700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: OBM RM JULY 1944
DESIGNATION: 946 9237 OBM RM JULY
MONUMENTATION: Tidal Station disk VM#: 18008
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 65° 15.8' N ( 65.26414) LONGITUDE: 166° 50.5' W (-166.84194)
The bench mark is a disk set in a gravel section on the east side of the Port
Clarence spit, 1.4 km (0.9 mi) south of Point Spencer, and 65 m (213 ft) from
apparent MHW. The bench mark is crimped to a stainless steel rod driven to an
unspecified depth.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 9469237 PUBLICATION DATE: 11/16/2010
Name: POINT SPENCER, PORT CLARENCE
AK
NOAA Chart: 16204 Latitude: 65° 15.4' N ( 65.25670)
USGS Quad: TELLER (B-4) Longitude: 166° 50.8' W (-166.84700)
T I D A L D A T U M S
Tidal datums at POINT SPENCER, PORT CLARENCE based on:
LENGTH OF SERIES: 45 DAYS
TIME PERIOD: July 20 - September 1 2010
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9468756 NOME, NORTON SOUND
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.391
MEAN HIGH WATER MHW = 0.362
MEAN SEA LEVEL MSL = 0.224
MEAN TIDE LEVEL MTL = 0.201
MEAN LOW WATER MLW = 0.040
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 1 1950 2.976 2.614
NO 2 1950 3.000 2.638
NO 3 1950 2.957 2.595
9237 A 2005 3.622 3.260
OBM RM 2 1945 2.258 1.896
OBM RM JULY 1944 2.863 2.501
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 9469237 PUBLICATION DATE: 11/16/2010
Name: POINT SPENCER, PORT CLARENCE
AK
NOAA Chart: 16204 Latitude: 65° 15.4' N ( 65.25670)
USGS Quad: TELLER (B-4) Longitude: 166° 50.8' W (-166.84700)
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.