U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 9466477 PUBLICATION DATE: 01/14/2011
Name: BETHEL, KUSKOKWIM RIVER
AK
NOAA Chart: 16304 Latitude: 60° 48.0' N ( 60.80000)
USGS Quad: BETHEL D-8 INSET Longitude: 161° 45.0' W (-161.75000)
To reach the bench marks from the airport, turn right and proceed SE 3.1 mi (5.1
km) on Chief Eddie Hoffman Highway to third Avenue, turn right on Third Avenue
and proceed NE 0.3 mi (0.4 km) to Main Street, turn right on Main Street and
proceed south 0.3 mi (0.5 km) to First Avenue, turn left on First Avenue and
proceed east 0.1 mi (0.2 km) to the station. The bench marks are along First
Avenue, Third Avenue and Main Street. The tide gauges were housed in the
Kuskokwim Ice Classic shed on the south side of First Avenue.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 7 1970
DESIGNATION: 946 6477 TIDAL 7
MONUMENTATION: Tidal Station disk VM#: 19661
AGENCY: US Coast and Geodetic Survey (USCGS) IDB PID#:
SETTING CLASSIFICATION: Copper-clad steel rod in sleeve OPUS PID:
LATITUDE: 60° 47.7' N ( 60.79558) LONGITUDE: 161° 46.0' W (-161.76644)
The primary bench mark is set below the wheel chair access ramp to the front
door of the National Guard Armory, 20.83 m (68.3 ft) NW of the centerline of
Fourth Avenue, 19.65 m (64.5 ft) ENE of power pole LIP31-9, 18.45 m (60.5 ft)
WSW of the SE corner of the building, and 0.35 m (1.1 ft) SSE of the southern
edge of the building. The bench mark is a disk, crimped to the top of a
copper-clad rod, driven to a depth of 16 m (53 ft), which projects 0.40 m (1.3
ft) above ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9466477 PUBLICATION DATE: 01/14/2011
Name: BETHEL, KUSKOKWIM RIVER
AK
NOAA Chart: 16304 Latitude: 60° 48.0' N ( 60.80000)
USGS Quad: BETHEL D-8 INSET Longitude: 161° 45.0' W (-161.75000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 6 1970
DESIGNATION: 946 6477 TIDAL 6
MONUMENTATION: Tidal Station disk VM#: 19662
AGENCY: US Coast and Geodetic Survey IDB PID#:
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID#: DF3625
LATITUDE: 60° 47.7' N ( 60.79469) LONGITUDE: 161° 45.8' W (-161.76294)
The bench mark is a set north of the red Moravian Church and south of Third
Street, 9.13 m (30.0 ft) SE of the southern edge of the pavement, 7.89 m (25.9
ft) NNE of the NW corner of the church, 5.71 m (18.7 ft) SE of power pole LIP70,
4.95 m (16.2 ft) NNW of the northern edge of the church and 0.25 m (0.82 ft)
east of a 0.89 m (2.9 ft) tall white witness post. The bench mark is a disk,
crimped to the top of a copper-clad rod, driven to a depth of 16 m (53 ft),
which projects 0.18 m (0.6 ft) above ground.
BENCH MARK STAMPING: 6477 B 2010
DESIGNATION: 946 6477 B
MONUMENTATION: Tidal Station disk VM#: 19664
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID#: BBCC65
LATITUDE: 60° 47.5' N ( 60.79133) LONGITUDE: 161° 45.3' W (-161.75569)
The bench mark is set south of First Avenue and the chain link fence north of a
row of thermal pipes, 71.15 m (233.4 ft) WSW of bench mark 946 6477 C, 14.73 m
(48.3 ft) ENE of power pole L4P94, 10.17 m (33.4 ft) NNW of the outside edge of
the steel piling seawall, and 9.10 m (29.9 ft) SSE of the centerline of First
Avenue. The datum point is set 0.13 m (0.4 ft) below grade, being the top of a
rounded off stainless steel rod driven 9.75 m (32 ft) to refusal and encased in
a 0.18 m (0.6 ft) diameter aluminum NGS Geodetic Control Mark logo cover with a
punch mark and 3D sleeve.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9466477 PUBLICATION DATE: 01/14/2011
Name: BETHEL, KUSKOKWIM RIVER
AK
NOAA Chart: 16304 Latitude: 60° 48.0' N ( 60.80000)
USGS Quad: BETHEL D-8 INSET Longitude: 161° 45.0' W (-161.75000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6477 C 2010
DESIGNATION: 946 6477 C
MONUMENTATION: Tidal Station disk VM#: 19665
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 60° 47.5' N ( 60.79139) LONGITUDE: 161° 45.3' W (-161.75442)
The bench mark is set near the southern most corner of the Kuskokwim Ice Classic
shed on the south side of First Avenue north of the chain link fence around the
park, 71.15 m (233.4 ft) ENE of bench mark 946 6477 B, 17.51 m (234.6 ft) NNW of
the outside edge of the steel piling seawall, 13.05 m (42.8 ft) SSE of the
centerline of First Avenue, and 8.50 m (27.9 ft) WSW of the power pole LP91-1.
The datum point is set 0.13 m (0.4 ft) below grade, being the top of a rounded
off stainless steel rod driven 9.75 m (36 ft) to refusal and encased in a 0.18 m
(0.6 ft) diameter aluminum NGS Geodetic Control Mark logo cover with a punch
mark and 3D sleeve.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9466477 PUBLICATION DATE: 01/14/2011
Name: BETHEL, KUSKOKWIM RIVER
AK
NOAA Chart: 16304 Latitude: 60° 48.0' N ( 60.80000)
USGS Quad: BETHEL D-8 INSET Longitude: 161° 45.0' W (-161.75000)
T I D A L D A T U M S
Tidal datums at BETHEL, KUSKOKWIM RIVER based on:
LENGTH OF SERIES: 4 MONTHS
TIME PERIOD: June 2010 - September 2010
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 = 1.117
MEAN HIGH WATER MHW = 0.843
MEAN SEA LEVEL MSL = 0.493
MEAN TIDE LEVEL MTL = 0.474
MEAN LOW WATER MLW = 0.105
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 7 1970 8.225 7.382
NO 6 1970 6.528 5.685
6477 B 2010 3.224 2.381
6477 C 2010 3.052 2.209
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9466477 PUBLICATION DATE: 01/14/2011
Name: BETHEL, KUSKOKWIM RIVER
AK
NOAA Chart: 16304 Latitude: 60° 48.0' N ( 60.80000)
USGS Quad: BETHEL D-8 INSET Longitude: 161° 45.0' W (-161.75000)
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.