U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 9454050 PUBLICATION DATE: 05/16/2003
Name: CORDOVA, ORCA INLET, PRINCE WILLIAM SD
AK
NOAA Chart: 16710 Latitude: 60° 33.5' N ( 60.55830)
USGS Quad: CORDOVA C-5 Longitude: 145° 45.2' W (-145.75300)
To reach the tidal bench marks from the U.S. Post Office and Court House on
Second Street, proceed north one block and turn left on C Street, then go one
block and turn right on First Street. After about 400 m (1312 ft), road joins
another road and becomes Railroad Avenue, proceed on and follow signs to ferry
dock. Tide house is located on the SE corner of pier. The tidal bench marks are
located in the general vicinity of ferry dock.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 4050 G 1982
MONUMENTATION: Tidal Station disk VM#: 1239
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 60° 33.3' N ( 60.55500) LONGITUDE: 145° 45.3' W (-145.75500)
The primary bench mark is a disk located 26.40 m (86.6 ft) east of the east side
of the corrugated metal warehouse, 7.60 m (24.9 ft) east of the centerline of
Ocean Dock Road, and 0.30 m (1.0 ft) west of tallest of three green transformer
boxes. The bench mark is set 0.10 m (0.3 ft) below ground level, crimped to the
top of a copper-clad rod driven to a depth of 4.3 m (14 ft) to refusal, and
encased in a 4-inch PVC pipe and cap which projects about 0.10 m (0.3 ft) above
ground level.
BENCH MARK STAMPING: NO 13 1970
MONUMENTATION: Tidal Station disk VM#: 1237
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Concrete dock OPUS PID#: BBBD28
LATITUDE: 60° 33.5' N ( 60.55756) LONGITUDE: 145° 45.3' W (-145.75572)
The bench mark is a disk set flush with the SW corner of the of the Cordova
Municipal concrete dock, about 1.6 km (1 mi) north of business district, 1.10 m
(3.6 ft) south of dock bollard, 0.40 m (1.3 ft) east of red light, 0.20 m (0.7
ft) north of south end of dock, and 0.30 m (1.0 ft) above wharf floor.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 9454050 PUBLICATION DATE: 05/16/2003
Name: CORDOVA, ORCA INLET, PRINCE WILLIAM SD
AK
NOAA Chart: 16710 Latitude: 60° 33.5' N ( 60.55830)
USGS Quad: CORDOVA C-5 Longitude: 145° 45.2' W (-145.75300)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4050 H 1982
MONUMENTATION: Tidal Station disk VM#: 1240
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID#: BBFS17
LATITUDE: 60° 33.1' N ( 60.55225) LONGITUDE: 145° 45.4' W (-145.75739)
The bench mark is a disk set along Railroad Avenue located 58.52 m (192.0 ft) SE
of the SE corner of a large light brown metal corrugated warehouse building,
7.19 m (23.6 ft) east of the centerline of Railroad Avenue, and 0.43 m (1.4 ft)
north of transformer box #341. The bench mark is set 0.10 m (0.3 ft) below
ground level, crimped to the top of a copper-clad rod driven to a depth of 9.1 m
(30 ft), and encased in a 4-inch PVC pipe and a cap which is flush with the
ground level.
BENCH MARK STAMPING: STA 34 + 78.55
DESIGNATION: 945 4050 STA 34
MONUMENTATION: Bench Mark disk VM#: 13124
AGENCY: AK Department of Transportation (ADOT) IDB PID#:
SETTING CLASSIFICATION: Pavement OPUS PID:
LATITUDE: 60° 32.1' N ( 60.53456) LONGITUDE: 145° 45.5' W (-145.75814)
The bench mark is a disk set in the pavement at Railroad Avenue, 111 m (363 ft)
south of bench mark 4050 H 1982, 25 m (83 ft) north of bench mark STA 35 +
60.68, and 0.15 m (0.5 ft) below grade with a cover MON cast into it.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 9454050 PUBLICATION DATE: 05/16/2003
Name: CORDOVA, ORCA INLET, PRINCE WILLIAM SD
AK
NOAA Chart: 16710 Latitude: 60° 33.5' N ( 60.55830)
USGS Quad: CORDOVA C-5 Longitude: 145° 45.2' W (-145.75300)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: STA 35 + 60.98
DESIGNATION: 945 4050 STA 35
MONUMENTATION: Bench Mark disk VM#: 13125
AGENCY: AK Department of Transportation (ADOT) IDB PID#:
SETTING CLASSIFICATION: Pavement OPUS PID:
LATITUDE: 60° 33.1' N ( 60.55117) LONGITUDE: 145° 45.5' W (-145.75825)
The bench mark is a disk set in pavement at the intersection of Railroad Avenue
and First Street, 21 m (70 ft) SSW of lightpole # 586, 16.61 m (54.5 ft) SE of
SE corner of a transformer box # 329, 15.50 m (50.9 ft) east of a stop sign, and
set 0.20 m (0.7 ft) below grade with a cover MON cast into it.
BENCH MARK STAMPING: STA 37 + 56.95
DESIGNATION: 945 4050 STA 37
MONUMENTATION: Bench Mark disk VM#: 13126
AGENCY: AK Department of Transportation (ADOT) IDB PID#:
SETTING CLASSIFICATION: Pavement OPUS PID:
LATITUDE: 60° 33.0' N ( 60.55081) LONGITUDE: 145° 45.5' W (-145.75864)
The bench mark is a disk set in pavement below the centerline of First Street,
44 m (145 ft) south of bench mark STA 35 + 60.98, 24.40 m (80.1 ft) NE of
telephone pole #56, 22.49 m (73.8 ft) SE of a lightpole # 585, 6.40 m (21.0 ft)
east of curb on side of street, and set 0.20 m (0.7 ft) below the grade with a
cover MON cast into it.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 9454050 PUBLICATION DATE: 05/16/2003
Name: CORDOVA, ORCA INLET, PRINCE WILLIAM SD
AK
NOAA Chart: 16710 Latitude: 60° 33.5' N ( 60.55830)
USGS Quad: CORDOVA C-5 Longitude: 145° 45.2' W (-145.75300)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4050 Q 1998
DESIGNATION: 945 4050 Q
MONUMENTATION: Tidal Station disk VM#: 14015
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Bedrock OPUS PID:
LATITUDE: 60° 33.3' N ( 60.55536) LONGITUDE: 145° 45.3' W (-145.75486)
The bench mark is a disk set flush in bedrock on the north side of the Ocean
Beach Road about 160 M (528 ft) west of Alaska Marine Highway Dock, 75 m (245
ft) west of the eastern side of bedrock outcrop, 48.50 m (159.1 ft) east of the
foot of a metal staircase, 19.80 m (65.0 ft) north of a power pole # 604-3, 10.0
m north of the centerline of Ocean Beach Road, and 1.00 m (3.3 ft) above grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 9454050 PUBLICATION DATE: 05/16/2003
Name: CORDOVA, ORCA INLET, PRINCE WILLIAM SD
AK
NOAA Chart: 16710 Latitude: 60° 33.5' N ( 60.55830)
USGS Quad: CORDOVA C-5 Longitude: 145° 45.2' W (-145.75300)
T I D A L D A T U M S
Tidal datums at CORDOVA, ORCA INLET, PRINCE WILLIAM SD based on:
LENGTH OF SERIES: 19 YEARS
TIME PERIOD: January 1983 - December 2001
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION:
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (11/11/1981) = 5.326
MEAN HIGHER HIGH WATER MHHW = 3.838
MEAN HIGH WATER MHW = 3.558
MEAN SEA LEVEL MSL = 2.056
MEAN TIDE LEVEL MTL = 2.009
MEAN LOW WATER MLW = 0.459
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (04/25/1967) = -1.489
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
4050 G 1982 9.272 5.713
NO 13 1970 6.561 3.002
4050 H 1982 9.244 5.685
STA 34 + 78.55 10.757 7.199
STA 35 + 60.98 11.482 7.923
STA 37 + 56.95 13.802 10.244
4050 Q 1998 14.539 10.981
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 9454050 PUBLICATION DATE: 05/16/2003
Name: CORDOVA, ORCA INLET, PRINCE WILLIAM SD
AK
NOAA Chart: 16710 Latitude: 60° 33.5' N ( 60.55830)
USGS Quad: CORDOVA C-5 Longitude: 145° 45.2' W (-145.75300)
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.