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National Ocean Service
Datums Page Page 1 of 5
Station ID: 9455760 PUBLICATION DATE: 06/27/2018
Name: NIKISKI, COOK INLET
AK
NOAA Chart: 16660 Latitude: 60° 41.0' N ( 60.68331)
USGS Quad: KENAI C4 Longitude: 151° 23.9' W (-151.39800)
To reach the tidal bench marks from the town of Soldotna, take Route 1 north to
Kenai, continue north past Kenai approximately 16 km (10 mi) until an area of
numerous oil refineries is reached, and proceed past the Phillips 66 refinery to
the Tesoro pipeline wharf located behind the Trading Bay Enterprises and Machine
Company. The bench marks are located in the general vicinity along the road
leading to the pier from the main gate. The tide gauges are located inside a
pumping control hut at the south inside corner of the wharf T section.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 5760 L 1983
DESIGNATION: 945 5760 L
MONUMENTATION: Tidal Station disk VM#: 1329
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID#: BBBB48
LATITUDE: 60° 41.1' N ( 60.68419) LONGITUDE: 151° 23.6' W (-151.39261)
The primary bench mark is a disk located at the head of the KPL dock for the
Tesoro Refinery in the middle of a gravel area next to a telephone pole, 23.50 m
(77.1 ft) ENE of the NE corner of a 5.80 m x 1.70 m x 2.60 m (19.0 ft x 5.5 ft x
8.5 ft) high grey utility building with six doors on the east wall, a detached
tin roof and surrounded by a black bull rail, 15.20 m (49.9 ft) NW of telephone
pole #P3A, 0.80 m (2.5 ft) east of telephone pole #P3 with a white witness sign
attached, and 0.63 m (2.1 ft) NNE of a 4 in x 4 in wooden post . The bench mark
is set 0.20 m (0.7 ft) below grade, crimped to the top of a copper clad rod
driven to a depth of 12.20 m (40.0 ft) and encased in a 6-inch PVC pipe and
aluminum logo cover which projects 0.10 m (0.3 ft) above the natural grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 9455760 PUBLICATION DATE: 06/27/2018
Name: NIKISKI, COOK INLET
AK
NOAA Chart: 16660 Latitude: 60° 41.0' N ( 60.68331)
USGS Quad: KENAI C4 Longitude: 151° 23.9' W (-151.39800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5760 M 1983
DESIGNATION: 945 5760 M
MONUMENTATION: Tidal Station disk VM#: 1330
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 60° 41.1' N ( 60.68483) LONGITUDE: 151° 23.5' W (-151.39186)
The benchmark is a disk set along the north side of the gravel road leading to
the KPL Oil Pier for Tesoro Refinery between telephone poles No. P5 and P6,
17.1 m (56.1 ft) NE of telephone pole #P5, 15.8 m (51.8 ft) SW of telephone pole
#P6, 7 m (23 ft) NW of the gravel road centerline, and 0.3 m (1 ft) SE of an
orange NOS witness post and sign directly below the power lines. The benchmark
is set 19 cm (0.6 ft) below grade, crimped to a copper-clad rod driven 14.6 m
(48 ft), and encased in a 4-inch PVC pipe with a logo cap and concrete kick
block projecting 0.1 m (0.3 ft) above the natural grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 9455760 PUBLICATION DATE: 06/27/2018
Name: NIKISKI, COOK INLET
AK
NOAA Chart: 16660 Latitude: 60° 41.0' N ( 60.68331)
USGS Quad: KENAI C4 Longitude: 151° 23.9' W (-151.39800)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5760 N 1983
DESIGNATION: 945 5760 N TIDAL
MONUMENTATION: Bench Mark disk VM#: 1331
AGENCY: National Ocean Service (NOS) IDB PID#: AB7148
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID#: AB7148
LATITUDE: 60° 41.2' N ( 60.68650) LONGITUDE: 151° 23.3' W (-151.38842)
The bench mark is a disk set along the northern side of the road leading to the
KPL oil pier at the Tesoro Refinery, 20.25 m (66.4 ft) south of the road running
north and south, 9.90 m (32.5 ft) SE of 16-inch steel pipes parallel with the
ground, 8.20 m (26.9 ft) NW of the centerline of the gravel road leading to KPL
dock, and 1.20 m (3.9 ft) NW of telephone pole #P14 with a white NOS witness
post sign attached. The bench mark is set 0.10 m (0.3 ft) below grade, crimped
to the top of a copper clad rod driven 7.00 m (23.0 ft) to refusal and encased
in a 4-inch PVC pipe which is encased in a 6-inch PVC pipe with logo cover.
BENCH MARK STAMPING: 5760 P 2002
DESIGNATION: 945 5760 P
MONUMENTATION: Tidal Station disk VM#: 16837
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete pier support OPUS PID:
LATITUDE: 60° 41.0' N ( 60.68353) LONGITUDE: 151° 23.7' W (-151.39514)
The bench mark is a disk set flush on top of the 12th concrete support from the
inshore end on the south side of the KPL dock, 5.60 m (18.4 ft) east of the
first expansion joint in pier, 2.30 m (7.5 ft) south of centerline of causeway,
and 0.20 m (0.7 ft) below the pier deck.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 9455760 PUBLICATION DATE: 06/27/2018
Name: NIKISKI, COOK INLET
AK
NOAA Chart: 16660 Latitude: 60° 41.0' N ( 60.68331)
USGS Quad: KENAI C4 Longitude: 151° 23.9' W (-151.39800)
T I D A L D A T U M S
Tidal datums at NIKISKI, COOK INLET based on:
LENGTH OF SERIES: 19 YEARS
TIME PERIOD: Oct 1996 - Sep 2010 & July 2012 - June 2017
TIDAL EPOCH: 2012-2016
CONTROL TIDE STATION: 9455500 SELDOVIA, COOK INLET
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (12/26/1976) = 8.657
MEAN HIGHER HIGH WATER MHHW = 6.262
MEAN HIGH WATER MHW = 6.039
MEAN SEA LEVEL MSL = 3.442
MEAN TIDE LEVEL MTL = 3.345
North American Vertical Datum NAVD88 = 2.205
MEAN LOW WATER MLW = 0.650
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (12/14/2008) = -1.925
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
5760 L 1983 12.839 6.800
5760 M 1983 13.193 7.154
5760 N 1983 26.359 20.320
5760 P 2002 10.652 4.613
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 9455760 PUBLICATION DATE: 06/27/2018
Name: NIKISKI, COOK INLET
AK
NOAA Chart: 16660 Latitude: 60° 41.0' N ( 60.68331)
USGS Quad: KENAI C4 Longitude: 151° 23.9' W (-151.39800)
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.