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Datums Page Page 1 of 7
Station ID: 9455963 PUBLICATION DATE: 12/05/2013
Name: GOOSE CREEK KNIK ARM, COOK INLET
AK
NOAA Chart: 16660 Latitude: 61° 23.6' N ( 61.39330)
USGS Quad: ANCHORAGE B-8 NW Longitude: 149° 50.8' W (-149.84700)
To reach the tidal bench marks from Anchorage, proceed by boat north for about
19 km (12 mi) to Goose Bay and Goose Creek on the west side of Knik Arm. The
bench marks can also be reached by road from Anchorage by going around Knik Arm
for about 103 km (64 mi). The bench marks are along the west shoreline of Knik
Arm about 2.4 km (1.5 mi) north of Goose Creek. In the area there is a row of
old pier pilings, a gravel road leading up from the beach to a gravel airstrip,
and a large excavated gravel pit. The tide gage and staff were on the row of
old pier pilings.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: TIDAL BM 4 1975
DESIGNATION: 945 5963 TIDAL 4
MONUMENTATION: Azimuth Mark disk VM#: 9565
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#:
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 61° 23.6' N ( 61.39261) LONGITUDE: 149° 50.9' W (-149.84894)
The primary bench mark is a disk located along the unnamed gravel road leading
to a small gravel parking area directly south of the Goose Bay Airstrip, 8.71 m
(28.6 ft) NE of the centerline of the unnamed gravel road, 6.46 m (21.2 ft) west
of 2 birch trees with the NW tree being 0.25 m (0.8 ft) in diameter and the SE
tree being 0.15 m (0.5 ft) in diameter, 6.41 m (21.0 ft) SE of a 0.25 m (0.8 ft)
diameter birch tree, and 3.62 m (11.9 ft) south of the start of a 9 m (30 ft)
high alder and birch tree covered bluff. The bench mark is set 14 cm (0.5 ft)
above grade, crimped to a copper rod driven to an unspecified depth.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 9455963 PUBLICATION DATE: 12/05/2013
Name: GOOSE CREEK KNIK ARM, COOK INLET
AK
NOAA Chart: 16660 Latitude: 61° 23.6' N ( 61.39330)
USGS Quad: ANCHORAGE B-8 NW Longitude: 149° 50.8' W (-149.84700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5963 A 2013
DESIGNATION: 945 5963 A
MONUMENTATION: Metal Rod VM#: 20882
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod with sleeve OPUS PID#: BBDG16
LATITUDE: 61° 23.5' N ( 61.39211) LONGITUDE: 149° 50.8' W (-149.84603)
The bench mark is a flange encased rod located at the east end of a small gravel
parking area directly south of the Goose Bay Airstrip, 51.41 m (168.7 ft) ESE of
the center of the round-about in the gravel parking lot, 13.55 m (44.5 ft) west
of the start of a 9 m (30 ft) alder-covered bluff, 11.14 m (36.5 ft) sloped
distance SSW of the top of the alder-covered bluff, and 7.43 m (24.4 ft) north
of the top of a 6 m (20 ft) high bluff that slopes down to Goose Bay. The datum
point is set 6 cm (0.2 ft) below grade, being the top of a stainless steel rod
driven 4.5 m (15 ft) to refusal, and encased in a 5-inch NOS logo cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
Station ID: 9455963 PUBLICATION DATE: 12/05/2013
Name: GOOSE CREEK KNIK ARM, COOK INLET
AK
NOAA Chart: 16660 Latitude: 61° 23.6' N ( 61.39330)
USGS Quad: ANCHORAGE B-8 NW Longitude: 149° 50.8' W (-149.84700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5963 B 2013
DESIGNATION: 945 5963 B
MONUMENTATION: Metal Rod VM#: 20883
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod with sleeve OPUS PID:
LATITUDE: 61° 23.6' N ( 61.39317) LONGITUDE: 149° 51.0' W (-149.84931)
The bench mark is a flange encased rod located along the unnamed gravel road
leading to a small gravel parking area directly south of the Goose Bay Airstrip,
23.88 m (78.3 ft) NNW of a 0.16 m (0.5 ft) diameter birch tree, 7.16 m (23.5 ft)
west of the centerline of the unnamed gravel road, 4.57 m (15.0 ft) SSE of a
clump of birch trees consisting of one 0.20 m (0.7 ft) in diameter and the other
0.25 m (0.8 ft) in diameter, and 3.04 m (10.0 ft) NE of the alder vegetation
line. The datum point is set 11 cm (0.4 ft) below grade, being the top of a
stainless steel rod driven 5.4 m (18 ft) to refusal, and encased in a 5-inch NOS
logo cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 9455963 PUBLICATION DATE: 12/05/2013
Name: GOOSE CREEK KNIK ARM, COOK INLET
AK
NOAA Chart: 16660 Latitude: 61° 23.6' N ( 61.39330)
USGS Quad: ANCHORAGE B-8 NW Longitude: 149° 50.8' W (-149.84700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5963 C 2013
DESIGNATION: 945 5963 C
MONUMENTATION: Metal Rod VM#: 20884
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod with sleeve OPUS PID:
LATITUDE: 61° 23.6' N ( 61.39383) LONGITUDE: 149° 50.9' W (-149.84889)
The bench mark is a flange encased rod located along the unnamed gravel road
leading to a small gravel parking area directly south of the Goose Bay Airstrip,
78 m (256 ft) NNE of tidal bench mark 945 5963 B, 14.09 m (46.2 ft) WNW of the
centerline of the unnamed gravel road that runs north-south, 8.12 m (26.6 ft)
north of a clump of five birch trees that are all 0.25 m (0.8 ft) in diameter,
7.56 m (24.8 ft) SSW of the centerline of the unnamed gravel road that runs
east-west, and 6.38 m (20.9 ft) NE of a 0.25 m (0.8 ft) diameter birch tree. The
datum point is set 8 cm (0.3 ft) below grade, being the top of a stainless steel
rod driven 6.0 m (20 ft) to refusal, and encased in a 5-inch NOS logo cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 9455963 PUBLICATION DATE: 12/05/2013
Name: GOOSE CREEK KNIK ARM, COOK INLET
AK
NOAA Chart: 16660 Latitude: 61° 23.6' N ( 61.39330)
USGS Quad: ANCHORAGE B-8 NW Longitude: 149° 50.8' W (-149.84700)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5963 D 2013
DESIGNATION: 945 5963 D
MONUMENTATION: Metal Rod VM#: 20885
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod with sleeve OPUS PID:
LATITUDE: 61° 23.6' N ( 61.39389) LONGITUDE: 149° 50.1' W (-149.83469)
The bench mark is a flange encased rod located along the unnamed gravel road
leading to a small gravel parking area directly south of the Goose Bay airport,
132 m (433 ft) west of tidal bench mark 945 5963 C, 14.73 m (48.3 ft) NNE of a
0.34 m (1.1 ft) diameter birch tree, 13.30 m (43.6 ft) WSW of a clump of four
birch trees that are all 0.10 m (0.3 ft) in diameter, 12.39 m (40.6 ft) ESE of a
0.17 m (0.6 ft) diameter birch tree, and 8.65 m (28.4 ft) south of the
centerline of the unnamed gravel road. The datum point is set 4 cm (0.1 ft)
below grade, being the top of a stainless steel rod driven 12.7 m (42 ft) to
refusal, and encased in a 5-inch NOS logo cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
Station ID: 9455963 PUBLICATION DATE: 12/05/2013
Name: GOOSE CREEK KNIK ARM, COOK INLET
AK
NOAA Chart: 16660 Latitude: 61° 23.6' N ( 61.39330)
USGS Quad: ANCHORAGE B-8 NW Longitude: 149° 50.8' W (-149.84700)
T I D A L D A T U M S
Tidal datums at GOOSE CREEK KNIK ARM, COOK INLET based on:
LENGTH OF SERIES: 30 Days
TIME PERIOD: July 3 2013 - August 1 2013
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 9455920 ANCHORAGE, KNIK ARM, COOK INLET
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 9.456
MEAN HIGH WATER MHW = 9.225
MEAN SEA LEVEL MSL = 5.386
MEAN TIDE LEVEL MTL = 4.953
MEAN LOW WATER MLW = 0.681
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
TIDAL BM 4 1975 17.587 8.362
5963 A 2013 14.695 5.471
5963 B 2013 26.677 17.452
5963 C 2013 27.663 18.439
5963 D 2013 28.196 18.971
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
Station ID: 9455963 PUBLICATION DATE: 12/05/2013
Name: GOOSE CREEK KNIK ARM, COOK INLET
AK
NOAA Chart: 16660 Latitude: 61° 23.6' N ( 61.39330)
USGS Quad: ANCHORAGE B-8 NW Longitude: 149° 50.8' W (-149.84700)
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
