U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 9467551 PUBLICATION DATE: 11/28/2011
Name: NUNAM IQUA (SHELDON POINT)
AK
NOAA Chart: 16006 Latitude: 62° 32.0' N ( 62.53294)
USGS Quad: KWIGUK C-6 Longitude: 164° 50.7' W (-164.84528)
To reach the bench marks from the western gravel loading pad at Northern end of
the Nunam Iqua (Sheldon?s Point) Airport, proceed NNE for 0.1 km (0.1 mi) to the
intersection with the boardwalk from the eastern gravel loading pad, then NNW on
another boardwalk for 0.3 km (0.2 mi) to another intersection with a boardwalk
oriented SW/NE, then NNE for 0.4 km (0.2 mi) along the SW/NE oriented boardwalk
until it turns to the NW, then 0.2 km (0.1 mi) to the intersection with the path
to the water intake pump. The bench marks are distributed throughout the
village mostly near the shore of the Yukon River. The tide gauge and orifices
are located near the city water intake pump.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 7551 C 2011
DESIGNATION: 946 7551 C
MONUMENTATION: Metal Rod VM#: 20132
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID#: BBCK30
LATITUDE: 62° 32.0' N ( 62.53297) LONGITUDE: 164° 50.8' W (-164.84597)
The primary bench mark is a metal rod set in the tundra, 19.60 m (64.3 ft) NE of
power pole # A-9, 16.05 m (52.6 ft) north of the fuel inlet pipe termination,
15.70 m (51.5 ft) SSW of the top of the bluff that leads down to the Yukon
River, 4.05 m (13.3 ft) SSE of the elevated stainless box containing the towns
water pump controls, 1.00 m (3.3 ft) NNE of an orange Carsonite witness post.
The datum point is set 10 cm (0.3 ft) below grade, being the top of a stainless
steel rod driven 9.7 m (32 ft) to refusal, and encased in a 6-inch PVC pipe with
concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 9467551 PUBLICATION DATE: 11/28/2011
Name: NUNAM IQUA (SHELDON POINT)
AK
NOAA Chart: 16006 Latitude: 62° 32.0' N ( 62.53294)
USGS Quad: KWIGUK C-6 Longitude: 164° 50.7' W (-164.84528)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7551 A 2011
DESIGNATION: 946 7551 A
MONUMENTATION: Metal Rod VM#: 20133
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 62° 31.9' N ( 62.53194) LONGITUDE: 164° 50.9' W (-164.84814)
The bench mark is a metal rod set in grass behind the old school building 99.25
m (325.6 ft) SW of bench mark 946 7551 B, 23.65 m (77.6 ft) west of power pole #
A7-2 U, 8.80 m (28.9 ft) SE of the centerline of elevated boardwalk leading to
river, 1.75 m (5.7 ft) NE of the northern most corner of old school building and
1.75 m (5.7 ft) NE of an orange Carsonite witness post. The datum point is set
10 cm (0.3 ft) below grade, being the top of a stainless steel rod driven 4.9 m
(16 ft) to refusal, and encased in a 6-inch PVC pipe with concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 9467551 PUBLICATION DATE: 11/28/2011
Name: NUNAM IQUA (SHELDON POINT)
AK
NOAA Chart: 16006 Latitude: 62° 32.0' N ( 62.53294)
USGS Quad: KWIGUK C-6 Longitude: 164° 50.7' W (-164.84528)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7551 B 2011
DESIGNATION: 946 7551 B
MONUMENTATION: Metal Rod VM#: 20134
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBFB63
LATITUDE: 62° 32.0' N ( 62.53258) LONGITUDE: 164° 50.8' W (-164.84689)
The bench mark is a metal rod set in the grass on the east side of boardwalk
level with the ground that leads to the Yukon River, 65.75 m (215.7 ft) SW of
bench mark 946 7551 C, 32.50 m (106.6 ft) NW of the centerline of an elevated
boardwalk that runs WSW/ENE, 11.70 m (38.4 ft) NE of power pole # A-8, 2.30 m
(7.5 ft) E of the centerline of the boardwalk that is level with the ground and
runs north/south to the river, 1.15 m (3.8 ft) NW of an orange Carsonite
witness post. The datum point is 12 cm (0.39 ft) below grade, being the top of a
stainless steel rod driven 7.3 m (24 ft) to refusal, and encased in a 6-inch PVC
pipe surrounded with concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 9467551 PUBLICATION DATE: 11/28/2011
Name: NUNAM IQUA (SHELDON POINT)
AK
NOAA Chart: 16006 Latitude: 62° 32.0' N ( 62.53294)
USGS Quad: KWIGUK C-6 Longitude: 164° 50.7' W (-164.84528)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7551 D 2011
DESIGNATION: 946 7551 D
MONUMENTATION: Metal Rod VM#: 20135
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID:
LATITUDE: 62° 32.0' N ( 62.53253) LONGITUDE: 164° 50.7' W (-164.84556)
The bench mark is a metal rod set in a clearing with grassy tundra near the
church of the old town site, 52.55 m (172.4 ft) SE of bench mark 946 7551 C,
42.70 m (140.1 ft) north of the centerline of an elevated boardwalk that runs
east/west, 34.80 m (114.2 ft) SSW of the top of the bluff leading down to the
Yukon River, 11.50 m (37.7 ft) NW of power pole # A-10, and 1.35 m (4.4 ft)
south of an orange Carsonite witness post. The datum point is 8 cm (0.26 ft)
below grade, being the top of a stainless steel rod driven 8.5 m (28 ft) to
refusal, and encased in a 6-inch PVC pipe with concrete kickblock.
BENCH MARK STAMPING: 7551 E 2011
DESIGNATION: 946 7551 E
MONUMENTATION: Metal Rod VM#: 20136
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID#: BBFB64
LATITUDE: 62° 31.9' N ( 62.53214) LONGITUDE: 164° 50.7' W (-164.84542)
The bench mark is a metal rod set in the grassy tundra near the old town site,
64.10 m (210.3 ft) SSW of the top of bluff leading down to the Yukon River,
29.00 m (95.1 ft) west of power pole # A-11, 23.10 m (75.8 ft) NNE of a water
pipe junction box that is square, and 2.11 m (6.9 ft) NNE of the centerline of
an elevated boardwalk leading SE. The datum point is 8 cm (0.26 ft) below grade,
being the top of a stainless steel rod driven 8.5 m (28 ft) to refusal, and
encased in a 6-inch PVC pipe with concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 9467551 PUBLICATION DATE: 11/28/2011
Name: NUNAM IQUA (SHELDON POINT)
AK
NOAA Chart: 16006 Latitude: 62° 32.0' N ( 62.53294)
USGS Quad: KWIGUK C-6 Longitude: 164° 50.7' W (-164.84528)
T I D A L D A T U M S
Tidal datums at NUNAM IQUA (SHELDON POINT) based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: July 2011 - September 2011
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 = 0.804
MEAN HIGH WATER MHW = 0.600
MEAN TIDE LEVEL MTL = 0.325
MEAN SEA LEVEL MSL = 0.320
MEAN LOW WATER MLW = 0.050
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
7551 C 2011 1.405 0.805
7551 A 2011 2.647 2.047
7551 B 2011 1.582 0.982
7551 D 2011 1.881 1.281
7551 E 2011 1.628 1.028
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 9467551 PUBLICATION DATE: 11/28/2011
Name: NUNAM IQUA (SHELDON POINT)
AK
NOAA Chart: 16006 Latitude: 62° 32.0' N ( 62.53294)
USGS Quad: KWIGUK C-6 Longitude: 164° 50.7' W (-164.84528)
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.