U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 11/02/1989
Station ID: 8414781 SUPERCEDED DATE: 04/21/2003
Name: WINTERPORT, PENOBSCOTT RIVER
MAINE
NOAA Chart: 13309 Latitude: 44° 38.2' N
USGS Quad: BUCKSPORT Longitude: 68° 50.5' W
To reach the tidal bench marks from the Post Office in Winterport, proceed north
on U.S. Highway 1A for 0.7 mile (1.1 km) to Commercial Street, turn right onto
Commercial Street and go 0.15 mile (0.24 km) to Winterport Marina at the end of
Commercial Street. The bench marks are within the marina complex and along
Water Street. The tide gage and staff were on the marina pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1970
MONUMENTATION: Survey Disk VM#: 1855
AGENCY: PID:
SETTING CLASSIFICATION: Granite Foundation
The bench mark is set flush in the granite foundation of an old well, 59.0 feet
(18.0 m) north of the center of the intersection of Commercial Street and a
paved road north, and 30.5 feet (9.3 m) west of power light pole #575.
BENCH MARK STAMPING: NO 2 1970
MONUMENTATION: Survey Disk VM#: 1857
AGENCY: PID:
SETTING CLASSIFICATION: Granite Boulder
The bench mark is set flush in a granite boulder, 185 feet (56 m) north of Bench
Mark NO 1 1970, 33.5 feet (10.2 m) north of the west end of a corrugated pipe
culvert, and 22 feet (7 m) west of the centerline of the paved road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 11/02/1989
Station ID: 8414781 SUPERCEDED DATE: 04/21/2003
Name: WINTERPORT, PENOBSCOTT RIVER
MAINE
NOAA Chart: 13309 Latitude: 44° 38.2' N
USGS Quad: BUCKSPORT Longitude: 68° 50.5' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4781-4
MONUMENTATION: Survey Disk VM#: 1858
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Monument
The bench mark is set flush in a concrete monument, SW of the fifth shed in a
row of five sheds, 13.8 feet (4.2 m) north of a wooden bulkhead, 12.6 feet (3.8
m) south of the doorway of the shed, and 0.7 foot (0.2 m) south of the SW corner
of the fifth shed.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 11/02/1989
Station ID: 8414781 SUPERCEDED DATE: 04/21/2003
Name: WINTERPORT, PENOBSCOTT RIVER
MAINE
NOAA Chart: 13309 Latitude: 44° 38.2' N
USGS Quad: BUCKSPORT Longitude: 68° 50.5' W
T I D A L D A T U M S
Tidal datums at WINTERPORT, PENOBSCOTT RIVER based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: AUGUST - SEPTEMBER 1984
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8415490 ROCKLAND
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (08/27/1984) = 14.27
MEAN HIGHER HIGH WATER MHHW = 12.60
MEAN HIGH WATER MHW = 12.07
MEAN TIDE LEVEL MTL = 6.20
MEAN LOW WATER MLW = 0.33
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (09/26/1984) = -2.28
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
NO 1 1970 22.46 10.39
NO 2 1970 23.19 11.12
4781-4 16.40 4.33
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 11/02/1989
Station ID: 8414781 SUPERCEDED DATE: 04/21/2003
Name: WINTERPORT, PENOBSCOTT RIVER
MAINE
NOAA Chart: 13309 Latitude: 44° 38.2' N
USGS Quad: BUCKSPORT Longitude: 68° 50.5' W
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 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.