U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 9465396 PUBLICATION DATE: 09/09/2008
Name: PLATINUM
AK
NOAA Chart: 16006 Latitude: 59° 2.8' N ( 59.04670)
USGS Quad: GOODNEWS BAY Longitude: 161° 49.1' W (-161.81800)
To reach tidal bench marks from the airport in Platinum, proceed north 3.7 km
(2.3 mi) along the gravel road out of town to the intersection with a single
lane gravel road on the right, turn right and proceed 49 m (160 ft) east to the
tide station. The bench marks are located west of the tide station on the north
tip of the south spit.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 5396 A 2007
DESIGNATION: 946 5396 A
MONUMENTATION: Tidal Station disk VM#: 18458
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBDS93
LATITUDE: 59° 2.8' N ( 59.04670) LONGITUDE: 161° 49.1' W (-161.81800)
The primary bench mark is set in a beach bluff, 370 m (1214 ft) east (106 true)
of bench mark 946 5396 E, 258 m (846 ft) east (80 true) of bench mark 946 5396
B, 65 m (213 ft) north of the high water mark on the north edge of the tidal
pond/lagoon, 49 m (161 ft) east of the centerline of a single lane road which
passes along the west side of a tidal pond, 34.50 m (113.2 ft) east of the SE
corner of a square tube frame for 4-green diesel tanks in a fuel dike, and 6.80
m (22.3 ft) west of the edge of vegetation on the beach bluff. The bench mark is
set 12 cm (0.4 ft) below grade, being the top of a stainless steel rod driven
15.2 m (51.8 ft) to refusal, and encased in a 8-inch PVC pipe with NOS logo
cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9465396 PUBLICATION DATE: 09/09/2008
Name: PLATINUM
AK
NOAA Chart: 16006 Latitude: 59° 2.8' N ( 59.04670)
USGS Quad: GOODNEWS BAY Longitude: 161° 49.1' W (-161.81800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5396 B 2007
DESIGNATION: 946 5396 B
MONUMENTATION: Tidal Station disk VM#: 18459
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 59° 2.8' N ( 59.04670) LONGITUDE: 161° 49.4' W (-161.82300)
The bench mark is set in the open tundra west of the Knik Gravel Camp, 258 m
(846 ft) west (260 true) of bench mark 946 5396 A, 156.67 m (514.0 ft) ESE (117
true) of bench mark 946 5396 D, 122.50 m (401.9 ft) east (92 true) of bench
mark 946 5396 C, 64.50 m (211.6 ft) north of the centerline of the gravel road
to the gravel camp. The bench mark is set 14 cm (0.5 ft) below grade, being the
top of a stainless steel rod driven 13.8 m (45.2 ft) to refusal, and encased in
a 8-inch PVC pipe with NOS logo cover.
BENCH MARK STAMPING: 5396 C 2007
DESIGNATION: 946 5396 C
MONUMENTATION: Tidal Station disk VM#: 18460
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 59° 2.8' N ( 59.04670) LONGITUDE: 161° 49.5' W (-161.82500)
The bench mark is set in a beach bluff west of the Knik Gravel Camp, 142.80 m
(468.5 ft) south (189 true) of bench mark 946 5396 E, 122.50 m (401.9 ft) west
(272 true) of bench mark 946 5396 B, and 71.17m (233.5 ft) SSE (167 true) of
bench mark 946 5396 D. The bench mark is set 15 cm (0.5 ft) below grade, being
the top of a stainless steel rod driven 15.8 m (51.9 ft) to refusal, and encased
in a 8-inch PVC pipe with NOS logo cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9465396 PUBLICATION DATE: 09/09/2008
Name: PLATINUM
AK
NOAA Chart: 16006 Latitude: 59° 2.8' N ( 59.04670)
USGS Quad: GOODNEWS BAY Longitude: 161° 49.1' W (-161.81800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5396 D 2007
DESIGNATION: 946 5396 D
MONUMENTATION: Tidal Station disk VM#: 18461
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 59° 2.8' N ( 59.04670) LONGITUDE: 161° 49.5' W (-161.82500)
The bench mark is set in a beach bluff west of the Knik Gravel Camp, 156.67 m
(514.0 ft) WNW (297 true) of bench mark 946 5396 B, 81.37 m (267.0 ft) SSW (208
true) of bench mark 946 5396 E, and 71.17 m (233.5 ft) NNW (346 true) of bench
mark 946 5396 C. The bench mark is set 13 cm (0.4 ft) below grade, being the top
of a stainless steel rod driven 6.1 m (19.9 ft) to refusal, and encased in a
8-inch PVC pipe with NOS logo cover.
BENCH MARK STAMPING: 5396 E 2007
DESIGNATION: 946 5396 E
MONUMENTATION: Tidal Station disk VM#: 18462
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 59° 2.8' N ( 59.04670) LONGITUDE: 161° 49.5' W (-161.82500)
The bench mark is set on top of a beach berm west of the Knik Gravel Camp,
176.19 m (578.1 ft) NW (325 true) of bench mark 946 5396 B, 142.85 m (468.7 ft)
north (8 true) of bench mark 946 5396 C, and 81.38 m (267.0 ft) NNE (28 true)
of bench mark 946 5396 D. The bench mark is set 14 cm (0.5 ft) below grade,
being the top of a stainless steel rod driven 5.9 m (19.4 ft) to refusal, and
encased in a 8-inch PVC pipe with NOS logo cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9465396 PUBLICATION DATE: 09/09/2008
Name: PLATINUM
AK
NOAA Chart: 16006 Latitude: 59° 2.8' N ( 59.04670)
USGS Quad: GOODNEWS BAY Longitude: 161° 49.1' W (-161.81800)
T I D A L D A T U M S
Tidal datums at PLATINUM based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: July 2007 - July 2007
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 = 2.876
MEAN HIGH WATER MHW = 2.055
MEAN SEA LEVEL MSL = 1.173
MEAN TIDE LEVEL MTL = 1.123
MEAN LOW WATER MLW = 0.191
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
5396 A 2007 4.031 1.976
5396 B 2007 3.898 1.843
5396 C 2007 4.020 1.965
5396 D 2007 4.522 2.467
5396 E 2007 4.597 2.542
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9465396 PUBLICATION DATE: 09/09/2008
Name: PLATINUM
AK
NOAA Chart: 16006 Latitude: 59° 2.8' N ( 59.04670)
USGS Quad: GOODNEWS BAY Longitude: 161° 49.1' W (-161.81800)
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.