U.S. DEPARTMENT OF COMMERCE
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National Ocean Service
Datums Page Page 1 of 7
Station ID: 9455558 PUBLICATION DATE: 04/10/2019
Name: COAL POINT, KACHEMAK BAY
AK
NOAA Chart: 16646 Latitude: 59° 36.1' N ( 59.60139)
USGS Quad: SELDOVIA C-4-1961 Longitude: 151° 24.6' W (-151.41056)
To reach the tide station from the US Post Office at 3658 Heath Street in Homer,
proceed south on Heath Street to the immediate intersection with AK-1 Sterling
Highway, turn left and proceed 2.0 km (1.2 mi) SE on AK-1 Sterling Highway
through a sharp bend to the left and a sharp bend to the right to the
intersection with Kachemak Drive on the left where the road name changes to
Homer Spit Road, continue straight on Homer Spit Road 6.8 km (4.2 mi) SE to the
Homer Ferry Terminal near the end of the spit. The tide station is located on
the Pioneer Dock and the bench marks are located on the dock, the Petro Marine
Services fuel facility and the Salty Dawg Saloon.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 5558 C 2018
DESIGNATION: 945 5558 C
MONUMENTATION: Bench Mark disk VM#: 22931
AGENCY: National Ocean Service IDB PID:
SETTING CLASSIFICATION: Massive concrete slab OPUS PID#: BBGD31
LATITUDE: 59° 36.1' N ( 59.60150) LONGITUDE: 151° 24.6' W (-151.41056)
The bench mark is a disk set in concrete on the NE corner of the east concrete
slab driveway to the Pioneer Dock at the Homer Ferry Terminal, 50.70 m (166.3
ft) SE of the SE corner of the Ferry Terminal building, 38.00 m (124.7 ft) ENE
of a fire hydrant, 0.64 m (2.1 ft) SW of the southern end of a wooden bull rail,
0.31 m (1.0 ft) NW of the east edge of a concrete slab.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 9455558 PUBLICATION DATE: 04/10/2019
Name: COAL POINT, KACHEMAK BAY
AK
NOAA Chart: 16646 Latitude: 59° 36.1' N ( 59.60139)
USGS Quad: SELDOVIA C-4-1961 Longitude: 151° 24.6' W (-151.41056)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: BM NO. 6 1965
DESIGNATION: 945 5558 TIDAL 6
MONUMENTATION: Survey disk VM#: 14735
AGENCY: Coast and Geodetic Survey (CGS) IDB PID:
SETTING CLASSIFICATION: Concrete floor OPUS PID:
LATITUDE: 59° 36.0' N ( 59.60075) LONGITUDE: 151° 24.7' W (-151.41169)
The bench mark is a disk set insde the pump house for the Petro Marine Services
tank farm, 5.90 m (19.4 ft) west of the east wall of the pump house, 0.54 m (1.8
ft) east of the west wall of the pump house, 0.21 m (0.7 ft) north of the south
wall of the pump house and flush with the floor.
BENCH MARK STAMPING: B 103 1965
DESIGNATION: 945 5558 B 103
MONUMENTATION: Survey disk VM#: 14737
AGENCY: National Ocean Survey (NOS) IDB PID#: TT0174
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 59° 36.1' N ( 59.60086) LONGITUDE: 151° 24.7' W (-151.41250)
The bench mark is a disk crimped to a 5/8-inch (16 mm) rod encased in a 4 inch
(10 cm) pipe in the tank farm containment area. It is 51.40 m (168.6 ft) WNW of
a light pole, 34.00 m (111.5 ft) WNW of mark c 103, 4.50 m (14.8 ft) south of
the south side of tank 17, 0.10 m (0.3 ft) north of the north side of tank 10
and about 0.15 m (0.5 ft) higher than the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
Station ID: 9455558 PUBLICATION DATE: 04/10/2019
Name: COAL POINT, KACHEMAK BAY
AK
NOAA Chart: 16646 Latitude: 59° 36.1' N ( 59.60139)
USGS Quad: SELDOVIA C-4-1961 Longitude: 151° 24.6' W (-151.41056)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: C 103 1965
DESIGNATION: 945 5558 C 103
MONUMENTATION: Survey disk VM#: 14738
AGENCY: National Ocean Survey (NOS) IDB PID#: TT0175
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID#: TT0175
LATITUDE: 59° 36.1' N ( 59.60103) LONGITUDE: 151° 24.7' W (-151.41164)
The bench mark is a disk crimped to a 5/8-inch (16 mm) rod encased in a 4 inch
(10 cm) pipe. It is 19.50 m (64.0 ft) west of a light pole, 18.10 m (59.4 ft)
ESE of the base of a ladder on tank 12, 5.30 m (17.4 ft) NW of the base of a
staircase entering the containment area and about 0.15 m (0.5 ft) higher than
the ground.
BENCH MARK STAMPING: 5558 A 1979
DESIGNATION: 945 5558 A
MONUMENTATION: Survey disk VM#: 14740
AGENCY: National Ocean Survey (NOS) IDB PID:
SETTING CLASSIFICATION: Base of a street light OPUS PID:
LATITUDE: 59° 36.1' N ( 59.60092) LONGITUDE: 151° 24.7' W (-151.41131)
The bench mark is a disk set in a 0.61 m (2.0 ft) x 0.61 m (2.0 ft) concrete pad
surrounded by pavement near the fuel truck filling station, 32.00 m (105.0 ft)
north of the access door to bench mark 945 5558 B, 12.10 m (39.7 ft) NNW of a
fixed yellow ladder, 6.70 m (22.0 ft) SSE of a light pole, 0.67 m (2.2 ft) SSW
of the edge of pavement and about flush with the driveway.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 9455558 PUBLICATION DATE: 04/10/2019
Name: COAL POINT, KACHEMAK BAY
AK
NOAA Chart: 16646 Latitude: 59° 36.1' N ( 59.60139)
USGS Quad: SELDOVIA C-4-1961 Longitude: 151° 24.6' W (-151.41056)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5558 B 1979
DESIGNATION: 945 5558 B
MONUMENTATION: Survey disk VM#: 14741
AGENCY: National Ocean Survey (NOS) IDB PID:
SETTING CLASSIFICATION: Concrete step OPUS PID:
LATITUDE: 59° 36.0' N ( 59.60064) LONGITUDE: 151° 24.7' W (-151.41136)
The bench mark is a disk in a concrete stair step inside the west entrance to
the Petro Marine Services Building, 1.00 m (3.3 ft) SE of the doorway, 0.83 m
(2.7 ft) south of the north side of the stairwell, 0.22 m (0.7 ft) north of the
south side of the stairwell and about 0.13 m (0.4 ft) higher than the ground
level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 9455558 PUBLICATION DATE: 04/10/2019
Name: COAL POINT, KACHEMAK BAY
AK
NOAA Chart: 16646 Latitude: 59° 36.1' N ( 59.60139)
USGS Quad: SELDOVIA C-4-1961 Longitude: 151° 24.6' W (-151.41056)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 945 5558 RAINIER'S DAWG
ALIAS: RAINIER'S DAWG 1978
MONUMENTATION: Survey disk VM#: 14742
AGENCY: National Ocean Survey (NOS) IDB PID:
SETTING CLASSIFICATION: Concrete floor OPUS PID:
LATITUDE: 59° 36.1' N ( 59.60189) LONGITUDE: 151° 25.3' W (-151.42144)
The bench mark is a disk set flush with the floor in a drill hole in the
concrete floor of the Salty Dawg Saloon, 6.55m (21.5 ft) NE of a steel bollard,
1.39m (4.6 ft) NNE of the center of the main entrance doorway, 0.91m (3.0 ft)
slant distance WSW of the end of the bar and flush with the floor.
BENCH MARK STAMPING: 5558 D 2018
DESIGNATION: 945 5558 D
MONUMENTATION: Bench Mark disk VM#: 22932
AGENCY: National Ocean Service IDB PID:
SETTING CLASSIFICATION: Concrete dock OPUS PID:
LATITUDE: 59° 36.1' N ( 59.60206) LONGITUDE: 151° 24.6' W (-151.40956)
The bench mark is a disk set in a 1.17 m (3.8 ft) x 0.87 m (2.9 ft) section of
concrete projecting from the SE end of the dock. It is 26.70 m (87.6 ft) WSW of
a bollard at the SE corner of the dock, 11.80 m (38.7 ft) SSW of the eastern end
of a covered walkway, 0.29 m (1.0 ft) south of the outside edge of a wooden bull
rail and flush with the dock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
Station ID: 9455558 PUBLICATION DATE: 04/10/2019
Name: COAL POINT, KACHEMAK BAY
AK
NOAA Chart: 16646 Latitude: 59° 36.1' N ( 59.60139)
USGS Quad: SELDOVIA C-4-1961 Longitude: 151° 24.6' W (-151.41056)
T I D A L D A T U M S
Tidal datums at COAL POINT, KACHEMAK BAY based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: September 2018 - November 2018
TIDAL EPOCH: 2012-2016
CONTROL TIDE STATION: 9455500 SELDOVIA, COOK INLET
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 5.618
MEAN HIGH WATER MHW = 5.362
MEAN SEA LEVEL MSL = 2.967
MEAN TIDE LEVEL MTL = 2.934
North American Vertical Datum NAVD88 = 1.553
MEAN LOW WATER MLW = 0.505
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
5558 C 2018 9.302 3.940
BM NO. 6 1965 8.252 2.890
B 103 1965 8.160 2.798
C 103 1965 8.136 2.774
5558 A 1979 8.111 2.749
5558 B 1979 8.140 2.778
945 5558 RAINIER'S DAWG 9.812 4.450
5558 D 2018 9.862 4.500
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
Station ID: 9455558 PUBLICATION DATE: 04/10/2019
Name: COAL POINT, KACHEMAK BAY
AK
NOAA Chart: 16646 Latitude: 59° 36.1' N ( 59.60139)
USGS Quad: SELDOVIA C-4-1961 Longitude: 151° 24.6' W (-151.41056)
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.