U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 9455595 PUBLICATION DATE: 06/29/2018
Name: BEAR COVE, KACHEMAK BAY
AK
NOAA Chart: 16647 Latitude: 59° 43.5' N ( 59.72500)
USGS Quad: SELDOVIA (C-3) Longitude: 151° 1.4' W (-151.02300)
To reach the bench marks from Homer, AK via boat, proceed NE for approximately
24.64 km (13.31 nm) through Kachemak Bay, turn SE at Bear Island and proceed
2.87 km (1.55 nm) through Bear Cove, turn NE after charted rock in the center of
Bear Cove and proceed 0.47 km (0.25 nm) to the tide gauge site. The tidal
benchmarks and tide staff are located along the northern shore of the end of the
cove surrounding the red boat house. The tide gauge site is located SE of the
tidal benchmarks up a hill.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 945-5595 B 2008
DESIGNATION: 945 5595 B
MONUMENTATION: Tidal Station disk VM#: 18884
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Boulder OPUS PID:
LATITUDE: 59° 43.5' N ( 59.72511) LONGITUDE: 151° 1.4' W (-151.02386)
The primary bench mark is set flush in a large rock , 145.10 m (476.05 ft) from
the prominent ledge at the SE end of the inlet, 102.50 m (336.29 ft) from bench
mark 945 5595 F, 58.70 m (192.59 ft) from the red shed on the NE corner of the
inlet, 5.00 m (16.40 ft) from the treeline, and 2.50 m (8.20 ft) above mean high
water.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 9455595 PUBLICATION DATE: 06/29/2018
Name: BEAR COVE, KACHEMAK BAY
AK
NOAA Chart: 16647 Latitude: 59° 43.5' N ( 59.72500)
USGS Quad: SELDOVIA (C-3) Longitude: 151° 1.4' W (-151.02300)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 945-5595 A 2008
DESIGNATION: 945 5595 A
MONUMENTATION: Tidal Station disk VM#: 18883
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Bedrock OPUS PID:
LATITUDE: 59° 43.5' N ( 59.72481) LONGITUDE: 151° 1.5' W (-151.02497)
The bench mark is set flush in bedrock at the treeline, 2.63 m (8.63 ft) above
mean high water, 157.00 m (515.09 ft) from the prominent ledge at the SE end of
the inlet, 107.30 m (352.03 ft) from the red shed on the NE corner of the inlet,
33.80 m (110.89 ft) from bench mark 945 5595 F.
BENCH MARK STAMPING: 945-5595 C 2008
DESIGNATION: 945 5595 C
MONUMENTATION: Tidal Station disk VM#: 18885
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Boulder OPUS PID:
LATITUDE: 59° 43.5' N ( 59.72533) LONGITUDE: 151° 1.4' W (-151.02311)
The bench mark is set flush in a rock within a small grouping of trees, 152.40 m
(500.00 ft) from bench mark 945 5595 F, 39.00 m (127.95 ft) from the red shed on
the northeast corner of the inlet, 9.00 m (29.53 ft) from the red house
overlooking the tide gauge site, and 13.82 m (45.33 ft) above mean high water.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 9455595 PUBLICATION DATE: 06/29/2018
Name: BEAR COVE, KACHEMAK BAY
AK
NOAA Chart: 16647 Latitude: 59° 43.5' N ( 59.72500)
USGS Quad: SELDOVIA (C-3) Longitude: 151° 1.4' W (-151.02300)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 945-5595 D 2008
DESIGNATION: 945 5595 D
MONUMENTATION: Tidal Station disk VM#: 18886
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Boulder OPUS PID:
LATITUDE: 59° 43.5' N ( 59.72486) LONGITUDE: 151° 1.4' W (-151.02286)
The bench mark is set flush in a boulder 143.40 m (470.35 ft) from bench mark
945 5595 F, 114.40 m (375.23 ft) from the prominent ledge on the SE end of the
inlet, 36.10 m (118.41 ft) from the red shed on the northeast corner of the
inlet, 3.00 m (9.8 ft) from treeline, and 0.41 m (1.34 ft) above mean high
water.
BENCH MARK STAMPING: 945-5595 E 2008
DESIGNATION: 945 5595 E
MONUMENTATION: Tidal Station disk VM#: 18887
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Bedrock OPUS PID:
LATITUDE: 59° 43.4' N ( 59.72392) LONGITUDE: 151° 1.4' W (-151.02369)
The bench mark is set in bedrock 422.80 m (1386.78 ft) from the prominent ledge
on the SW end of the inlet, 123.10 m (403.77 ft) from the red shed on the NE
corner of the inlet, 116.00 m (380.48 ft) from bench mark 945 5595 F, 1.00 m
(3.2 ft) from the tree line, and 2.40 m (7.86 ft) above mean high water.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 9455595 PUBLICATION DATE: 06/29/2018
Name: BEAR COVE, KACHEMAK BAY
AK
NOAA Chart: 16647 Latitude: 59° 43.5' N ( 59.72500)
USGS Quad: SELDOVIA (C-3) Longitude: 151° 1.4' W (-151.02300)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5595 F 2009
DESIGNATION: 945 5595 F
MONUMENTATION: Tidal Station disk VM#: 19331
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Bedrock OPUS PID:
LATITUDE: 59° 43.5' N ( 59.72456) LONGITUDE: 151° 1.5' W (-151.02533)
The benchmark is set flush in bedrock 142.70 m (468.06 ft) from the prominent
ledge of the SE end of the inlet, 123.80 m (406.06 ft) from the red shed on the
NE corner of the inlet, 102.4 m (335.87 ft) from bench mark 945-5595 B, 5 m
(15.0 ft) from the tree line, and 0.73 m (2.40 ft) above mean high water.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 9455595 PUBLICATION DATE: 06/29/2018
Name: BEAR COVE, KACHEMAK BAY
AK
NOAA Chart: 16647 Latitude: 59° 43.5' N ( 59.72500)
USGS Quad: SELDOVIA (C-3) Longitude: 151° 1.4' W (-151.02300)
T I D A L D A T U M S
Tidal datums at BEAR COVE, KACHEMAK BAY based on:
LENGTH OF SERIES: 31 DAYS
TIME PERIOD: July 29, 2008 - August 28, 2008
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 = 5.684
MEAN HIGH WATER MHW = 5.433
MEAN SEA LEVEL MSL = 2.999
MEAN TIDE LEVEL MTL = 2.969
MEAN LOW WATER MLW = 0.506
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
945-5595 B 2008 7.549 2.116
945-5595 A 2008 7.415 1.982
945-5595 C 2008 18.871 13.439
945-5595 D 2008 5.455 0.022
945-5595 E 2008 7.439 2.007
5595 F 2009 5.521 0.089
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 9455595 PUBLICATION DATE: 06/29/2018
Name: BEAR COVE, KACHEMAK BAY
AK
NOAA Chart: 16647 Latitude: 59° 43.5' N ( 59.72500)
USGS Quad: SELDOVIA (C-3) Longitude: 151° 1.4' W (-151.02300)
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.