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National Ocean Service
Datums Page Page 1 of 5
Station ID: 9455711 PUBLICATION DATE: 07/25/2018
Name: CAPE KASILOF, COOK INLET
AK
NOAA Chart: 16660 Latitude: 60° 20.2' N ( 60.33670)
USGS Quad: KENAI B-4 Longitude: 151° 22.8' W (-151.38000)
To reach the tidal bench marks and the Cape Kasilof tide gauge, head west out of
the Kenai River from Kenai into Cook Inlet. Head south into Cook Inlet to Cape
Kasilof. The tide station is located 5.6 km (3.0 nm) south of Green Buoy "1" on
a beach. Permission needs to be obtained from the property owner, Bob Arnold.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 4 1974
DESIGNATION: 945 5711 TIDAL 4
MONUMENTATION: Bench Mark disk VM#: 14164
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock OPUS PID:
LATITUDE: 60° 20.2' N ( 60.33670) LONGITUDE: 151° 22.8' W (-151.38000)
The primary bench mark is a disk set on a large rock, 49 m (160 ft) SW (227
degrees magnetic) from bench mark 3 1974, 46 m (150 ft) at the right angle from
the cliff, 38 m (125 ft) SW (210 degrees magnetic) from bench mark 2 1974, and
is underwater at high tide.
BENCH MARK STAMPING: 1 1974
DESIGNATION: 945 5711 TIDAL 1
MONUMENTATION: Bench Mark disk VM#: 14161
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock OPUS PID:
LATITUDE: 60° 20.2' N ( 60.33670) LONGITUDE: 151° 22.8' W (-151.38000)
The bench mark is a disk located on the SW side of the northern-most rock of a
group of ten large rocks, 305 m (1000 ft) south of the 15 m x 15 m (50 ft x 50
ft) rock at the base of a cliff, 15 m (50 ft) from the base of a dirt cliff, and
1 m (3 ft) above the beach.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9455711 PUBLICATION DATE: 07/25/2018
Name: CAPE KASILOF, COOK INLET
AK
NOAA Chart: 16660 Latitude: 60° 20.2' N ( 60.33670)
USGS Quad: KENAI B-4 Longitude: 151° 22.8' W (-151.38000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2 1974
DESIGNATION: 945 5711 TIDAL 2
MONUMENTATION: Bench Mark disk VM#: 14162
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock OPUS PID:
LATITUDE: 60° 20.2' N ( 60.33670) LONGITUDE: 151° 22.8' W (-151.38000)
The bench mark is a disk set on the top of the largest rock of size 2 m x 6 m
x 1 m (8 ft x 20 ft x 4 ft), 133 m (435 ft) SE (161.5 degrees magnetic) of
bench mark 1 1974.
BENCH MARK STAMPING: 3 1974
DESIGNATION: 945 5711 TIDAL 3
MONUMENTATION: Bench Mark disk VM#: 14163
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock OPUS PID:
LATITUDE: 60° 20.2' N ( 60.33670) LONGITUDE: 151° 22.8' W (-151.38000)
The bench mark is a disk set in the north top portion of a large rock, closest
to the group of rocks to the cliff, 26 m (85 ft) SE (132 degrees magnetic) of
bench mark 2 1974, and 9 m (30 ft) from the base of the cliff.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9455711 PUBLICATION DATE: 07/25/2018
Name: CAPE KASILOF, COOK INLET
AK
NOAA Chart: 16660 Latitude: 60° 20.2' N ( 60.33670)
USGS Quad: KENAI B-4 Longitude: 151° 22.8' W (-151.38000)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5 1974
DESIGNATION: 945 5711 TIDAL 5
MONUMENTATION: Bench Mark disk VM#: 14165
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Rock OPUS PID:
LATITUDE: 60° 20.2' N ( 60.33670) LONGITUDE: 151° 22.8' W (-151.38000)
The bench mark is a disk set in the NE corner of the largest rock in the group,
84 m (275 ft) from the base of the cliff, 76 m (250 ft) SW (217 degrees
magnetic) of bench mark 2 1974, and is underwater at the high tide.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9455711 PUBLICATION DATE: 07/25/2018
Name: CAPE KASILOF, COOK INLET
AK
NOAA Chart: 16660 Latitude: 60° 20.2' N ( 60.33670)
USGS Quad: KENAI B-4 Longitude: 151° 22.8' W (-151.38000)
T I D A L D A T U M S
Tidal datums at CAPE KASILOF, COOK INLET based on:
LENGTH OF SERIES: 30 DAYS
TIME PERIOD: Jul 19 1999 - Aug 17 1999
TIDAL EPOCH: 2012-2016
CONTROL TIDE STATION: 9455760 NIKISKI, COOK INLET
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 6.123
MEAN HIGH WATER MHW = 5.922
MEAN SEA LEVEL MSL = 3.315
MEAN TIDE LEVEL MTL = 3.270
MEAN LOW WATER MLW = 0.619
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
4 1974 5.448 -0.474
1 1974 7.628 1.706
2 1974 7.544 1.622
3 1974 9.272 3.350
5 1974 5.105 -0.816
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9455711 PUBLICATION DATE: 07/25/2018
Name: CAPE KASILOF, COOK INLET
AK
NOAA Chart: 16660 Latitude: 60° 20.2' N ( 60.33670)
USGS Quad: KENAI B-4 Longitude: 151° 22.8' W (-151.38000)
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.