U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 7
Station ID: 8415490 PUBLICATION DATE: 04/21/2003
Name: ROCKLAND
ME
NOAA Chart: 13307 Latitude: 44° 6.3' N ( 44.10500)
USGS Quad: Rockland Longitude: 69° 6.1' W ( -69.10170)
To reach the tidal bench marks from U.S. Highway 1, north or south, follow U.S.
Highway 1 to downtown Rockland (Main Street), turn right (east) on Tillson
Avenue and follow it to the U.S. Coast Guard Station. The bench marks are
located within 1 mile (1.6 m) radius of the tide station. The tide house
waslocated to the left of the entrance on the north face of the dock.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 5490 K 1976
DESIGNATION: 841 5490 K
MONUMENTATION: Survey disk VM#: 1878
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Porch foundation OPUS PID:
LATITUDE: 44° 6.3' N ( 44.10500) LONGITUDE: 69° 6.1' W ( -69.10170)
The bench mark is located at the entrance to the National Sea Products Building
on Tillson Avenue, 26.7 feet (8.1 m) south of the centerline of Tillson Avenue,
10.9 feet (3.3 m) east of the NW corner of the porch, and 1.7 feet (0.5 m) SW of
the NE corner of the porch. The bench mark is set in the concrete foundation
for the porch 3.3 feet (1.0 m) above the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 8415490 PUBLICATION DATE: 04/21/2003
Name: ROCKLAND
ME
NOAA Chart: 13307 Latitude: 44° 6.3' N ( 44.10500)
USGS Quad: Rockland Longitude: 69° 6.1' W ( -69.10170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 36.256 D 18 1933
DESIGNATION: D 18
MONUMENTATION: Survey disk VM#: 1875
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: PE0886
SETTING CLASSIFICATION: Building OPUS PID:
LATITUDE: 44° 6.0' N ( 44.10000) LONGITUDE: 69° 6.6' W ( -69.11000)
The bench mark is located on the east wall of the City Hall building, 47.5 feet
(14.5 m) west of the centerline of Union Street, 25.7 feet (7.8 m) NW of a flag
pole and 21.0 feet (6.4 m) north of the centerline of the main entrance to City
Hall. The bench mark is set vertically 0.7 foot (0.2 m) above the sidewalk.
BENCH MARK STAMPING: NO 6 1973
DESIGNATION: 841 5490 TIDAL 6
MONUMENTATION: Survey disk VM#: 1876
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Truck scale foundation OPUS PID:
LATITUDE: 44° 6.3' N ( 44.10500) LONGITUDE: 69° 6.1' W ( -69.10170)
The bench mark is located on the west side of Tillson Avenue between Park Drive
and Lime Street, 112.2 feet (34.2 m) west of the corner of Lime Street and
Tillson Avenue and 20.3 feet (6.2 m) south of the centerline of Tillson Avenue.
The bench mark is set in the east corner of a truck scale foundation.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
Station ID: 8415490 PUBLICATION DATE: 04/21/2003
Name: ROCKLAND
ME
NOAA Chart: 13307 Latitude: 44° 6.3' N ( 44.10500)
USGS Quad: Rockland Longitude: 69° 6.1' W ( -69.10170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5490 J 1976
DESIGNATION: 841 5490 J
MONUMENTATION: Survey disk VM#: 1877
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete ramp OPUS PID:
LATITUDE: 44° 6.3' N ( 44.10500) LONGITUDE: 69° 6.1' W ( -69.10170)
The bench mark is located at 20 Park Drive, 31.5 feet (9.6 m) NW of the NE
corner of the School House Warehouse, 30.5 feet(9.3 m) NE of the NW corner of
the TOGS Warehouse, and 3.0 feet (0.9 m) south of the north edge of the loading
platform. The bench mark is set flush in the center of the north loading ramp.
The mark is now indoors as a wooden shed was built on the former loading ramp.
BENCH MARK STAMPING: 5490 A 1978
DESIGNATION: 841 5490 A
MONUMENTATION: Survey disk VM#: 1879
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Oil tank foundation OPUS PID:
LATITUDE: 44° 6.3' N ( 44.10500) LONGITUDE: 69° 6.1' W ( -69.10170)
The bench mark is located on the south side of an oil tank at OHara & Sons dock,
37 feet (11 m) east of the SE corner of the main building of OHara & Sons, 30.7
feet (9.4 m) west of the centerline of Tillson Avenue, and 12.8 feet (3.9 m)
west of the chain link fence around the Coast Guard Station. The bench mark is
set flush in concrete foundation 1 foot (0.3 m) above the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 8415490 PUBLICATION DATE: 04/21/2003
Name: ROCKLAND
ME
NOAA Chart: 13307 Latitude: 44° 6.3' N ( 44.10500)
USGS Quad: Rockland Longitude: 69° 6.1' W ( -69.10170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5490 B 1978
DESIGNATION: 841 5490 B
MONUMENTATION: Survey disk VM#: 1880
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete cap of a retaining wall OPUS PID:
LATITUDE: 44° 6.3' N ( 44.10500) LONGITUDE: 69° 6.1' W ( -69.10170)
The bench mark is located between North Lubic Manufacturing & Canning Company
and OHara & Sons, Incorporated, 63.5 feet (19.4 m) south of the SW entrance to
Lubic Manufacturing & Canning Company, 34.3 feet (10.5 m) east of the SE corner
of a chain link fence surrounding an underground tank, 33.2 feet (10.1 m) north
of the centerline of Tillson Avenue, and 30 feet (9 m) west of SW corner of
asbestos shingle garage of OHara and Sons. The bench mark is set flush in a
concrete cap of a retaining wall.
BENCH MARK STAMPING: NO 12 1975 1981
DESIGNATION: 841 5490 TIDAL 12 RESET
MONUMENTATION: Survey disk VM#: 1882
AGENCY: National Ocean Survey (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete walkway OPUS PID:
LATITUDE: 44° 6.3' N ( 44.10500) LONGITUDE: 69° 6.1' W ( -69.10170)
The bench mark is located at the intersection of Main Street and Tillson Avenue,
36.1 feet (11.0 m) south of the center of Tillson Avenue and 30.8 feet (9.4 m)
east of the center of Main Street. The bench mark is set in the concrete
walkway at the front of the Fred S. James and Co. insurance brokers.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 8415490 PUBLICATION DATE: 04/21/2003
Name: ROCKLAND
ME
NOAA Chart: 13307 Latitude: 44° 6.3' N ( 44.10500)
USGS Quad: Rockland Longitude: 69° 6.1' W ( -69.10170)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: ARLENE
DESIGNATION: 841 5490 ARLENE
MONUMENTATION: Survey disk VM#: 1883
AGENCY: US Coast Guard (USCG) IDB PID#:
SETTING CLASSIFICATION: Concrete bulkhead OPUS PID:
LATITUDE: 44° 6.3' N ( 44.10500) LONGITUDE: 69° 6.1' W ( -69.10170)
The bench mark is located in the U.S. Coast Guard compound, 87.9 feet (26.8 m)
south of the inside of the NW corner of the pier, 60.0 feet (18.3 m) north of
the south face of the pier, 50.2 feet (15.3 m) NNW of a light pole, and 5.5 feet
(1.7 m) west of the west face of a trailer. The bench mark is set flush in the
concrete cap of bulkhead.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
Station ID: 8415490 PUBLICATION DATE: 04/21/2003
Name: ROCKLAND
ME
NOAA Chart: 13307 Latitude: 44° 6.3' N ( 44.10500)
USGS Quad: Rockland Longitude: 69° 6.1' W ( -69.10170)
T I D A L D A T U M S
Tidal datums at ROCKLAND based on:
LENGTH OF SERIES: 14 Years
TIME PERIOD: July 1973 - June 1987
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8418150 PORTLAND, CASCO BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (03/18/1976) = 4.319
MEAN HIGHER HIGH WATER MHHW = 3.223
MEAN HIGH WATER MHW = 3.100
MEAN SEA LEVEL MSL = 1.624
MEAN TIDE LEVEL MTL = 1.609
MEAN LOW WATER MLW = 0.119
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (03/18/1976) = -0.795
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
5490 K 1976 8.957 5.857
36.256 D 18 1933 12.592 9.492
NO 6 1973 9.365 6.265
5490 J 1976 9.613 6.513
5490 A 1978 5.899 2.799
5490 B 1978 5.322 2.222
NO 12 1975 1981 10.921 7.821
ARLENE 5.418 2.318
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
Station ID: 8415490 PUBLICATION DATE: 04/21/2003
Name: ROCKLAND
ME
NOAA Chart: 13307 Latitude: 44° 6.3' N ( 44.10500)
USGS Quad: Rockland Longitude: 69° 6.1' W ( -69.10170)
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.