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National Ocean Service
Datums Page Page 1 of 5
Station ID: 9455204 PUBLICATION DATE: 04/21/2003
Name: UPPER NORTHWESTERN FIORD
AK
NOAA Chart: 16682 Latitude: 59° 47.4' N ( 59.79000)
USGS Quad: SELDOVIA (D-1) Longitude: 150° 1.9' W (-150.03200)
To reach the benchmarks from Seward via boat, proceed 15 km (8 nm) SSE along
Resurrection Bay to Calisto Head, then 32.5 km (17.6 nm) south along
Resurrection Bay to Aialik Cape, then 9.1 km (4.9 nm) west across Aialik Bay to
the axis of Aialik Bay north of Harbor Island, then 10.4 km (5.6 nm) SSW to the
center of the passage between Aligo Point and the southern tip of Granite
Island, then 25.0 km (13.5 nm) NW along Granite Passage and Harris Bay to the
tide station on a small island at high water near the SE corner of Striation
Island. The benchmarks are located along the east-west axis of the island. The
tide station was located between benchmarks 9455204 B 2000 and 9455204 C 2000.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 9455204 A 2000
DESIGNATION: 945 5204 A
MONUMENTATION: Tidal Station disk VM#: 16356
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 59° 47.4' N ( 59.79000) LONGITUDE: 150° 1.9' W (-150.03200)
The primary benchmark is a disk set in a rock outcrop on the SE side of the
island, 13 m (43 ft) NE of benchmark 9455204 B 2000, 5 m (16 ft) NW of a
stainless steel eyebolt cemented into rock, 4 m (14 ft) north of a stainless
steel eye bolt cemented into rock, and 4 m (12 ft) above the apparent high water
line.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9455204 PUBLICATION DATE: 04/21/2003
Name: UPPER NORTHWESTERN FIORD
AK
NOAA Chart: 16682 Latitude: 59° 47.4' N ( 59.79000)
USGS Quad: SELDOVIA (D-1) Longitude: 150° 1.9' W (-150.03200)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9455204 B 2000
DESIGNATION: 945 5204 B
MONUMENTATION: Tidal Station disk VM#: 16357
AGENCY: Natonal Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 59° 47.4' N ( 59.79000) LONGITUDE: 150° 1.9' W (-150.03200)
The benchmark is a disk set in a rock outcrop on top of the south side of the
island, 49 m (161 ft) ESE of benchmark 9455204 E 2000, 31.61 m (103.7 ft) east
of benchmark 9455204 D 2000, 18 m (59 ft) east of benchmark 9455204 C 2000, and
12 m (39 ft) WSW of a steel eyebolt cemented into rock.
BENCH MARK STAMPING: 9455204 C 2000
DESIGNATION: 945 5204 C
MONUMENTATION: Tidal Station disk VM#: 16358
AGENCY: Natonal Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 59° 47.4' N ( 59.79000) LONGITUDE: 150° 1.9' W (-150.03200)
The benchmark is a disk set in a rock outcrop on the top ridge of the island 37
m x 4m (121 ft x 13 ft) wide, 32 m (105 ft) east of benchmark 9455204 E 2000,
18 m (59 ft) west of benchmark 9455204 B 2000, 14 m (47 ft) east of benchmark
9455204 D 2000, 12 m (39 ft) WSW of the highest point of the ridge, 6 m (20 ft)
from the south tip of the ridge, and 1 m (3 ft) from the north edge of the
ridge.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9455204 PUBLICATION DATE: 04/21/2003
Name: UPPER NORTHWESTERN FIORD
AK
NOAA Chart: 16682 Latitude: 59° 47.4' N ( 59.79000)
USGS Quad: SELDOVIA (D-1) Longitude: 150° 1.9' W (-150.03200)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 9455204 D 2000
DESIGNATION: 945 5204 D
MONUMENTATION: Tidal Station disk VM#: 16359
AGENCY: Natonal Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 59° 47.4' N ( 59.79000) LONGITUDE: 150° 1.9' W (-150.03200)
The benchmark is a disk set in a rock outcrop on the top ridge of the island 37
m x 4m (121 ft x 13 ft) wide, 31.61 m (103.7 ft) west of benchmark 9455204 B
2000, 18 m (58 ft) east of benchmark 9455204 E 2000, 14 m (47 ft) west of
benchmark 9455204 C 2000, and 4 m (12 ft) west of the highest point on the
ridge.
BENCH MARK STAMPING: 9455204 E 2000
DESIGNATION: 945 5204 E
MONUMENTATION: Tidal Station disk VM#: 16360
AGENCY: Natonal Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock outcrop OPUS PID:
LATITUDE: 59° 47.4' N ( 59.79000) LONGITUDE: 150° 1.9' W (-150.03200)
The benchmark is a disk set in a rock outcrop on the top ridge of the island 37
m x 4m (121 ft x 13 ft) wide, 49 m (161 ft) WNW of benchmark 9455204 B 2000, 32
m (105 ft) west of benchmark 9455204 C 2000, 21 m (69 ft) west of the highest
point on the ridge, and 18 m (59 ft) west of benchmark 9455204 D 2000.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9455204 PUBLICATION DATE: 04/21/2003
Name: UPPER NORTHWESTERN FIORD
AK
NOAA Chart: 16682 Latitude: 59° 47.4' N ( 59.79000)
USGS Quad: SELDOVIA (D-1) Longitude: 150° 1.9' W (-150.03200)
T I D A L D A T U M S
Tidal datums at UPPER NORTHWESTERN FIORD based on:
LENGTH OF SERIES: 1 Month
TIME PERIOD: August 2000 - August 2000
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9455090 SEWARD, RESURRECTION BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 3.303
MEAN HIGH WATER MHW = 3.031
MEAN SEA LEVEL MSL = 1.729
MEAN TIDE LEVEL MTL = 1.722
MEAN LOW WATER MLW = 0.413
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
9455204 A 2000 4.905 1.874
9455204 B 2000 9.276 6.245
9455204 C 2000 12.008 8.977
9455204 D 2000 13.212 10.181
9455204 E 2000 11.333 8.302
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9455204 PUBLICATION DATE: 04/21/2003
Name: UPPER NORTHWESTERN FIORD
AK
NOAA Chart: 16682 Latitude: 59° 47.4' N ( 59.79000)
USGS Quad: SELDOVIA (D-1) Longitude: 150° 1.9' W (-150.03200)
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.
Station Location
Published bench mark
Unpublished bench mark
