U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8417208 PUBLICATION DATE: 02/27/2006
Name: RICHMOND, KENNEBEC RIVER
ME
NOAA Chart: 13298 Latitude: 44° 5.3' N ( 44.08830)
USGS Quad: GARDINER Longitude: 69° 47.9' W ( -69.79830)
FROM I-295, PROCEED NORTH ON I-295 TO EXIT 43 STATE ROUTE 197 (RICHMOND),
PROCEED EAST ON STATE ROUTE 197 FOR 5.6 KM (3.5 MI) TO STATE ROUTE 24, CONTINUE
NORTH (TURN LEFT) ON STATE ROUTE 24 FOR 50 YARDS TO THE SWANN ISLAND BOAT
LANDING ON THE RIGHT. THE BENCH MARKS ARE LOCATED IN THE FORT RICHMOND CITY
PARK, THE OLD POST OFFICE BUILDING, AND THE WATER COMPANY BUILDING. THE TIDE
GAGE IS LOCATED ON A FLOATING BULKHEAD AT THE SWANN ISLAND BOAT LANDING.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 7208 A 2005
DESIGNATION: 841 7208 A
MONUMENTATION: Tidal Station disk VM#: 17924
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Pier foundation OPUS PID:
LATITUDE: 44° 5.3' N ( 44.08830) LONGITUDE: 69° 47.9' W ( -69.79830)
The primary bench mark is a disk set in the concrete foundation of the removable
pier located at the Swann Island tour passanger pick-up, 28.79 m (94.5 ft) south
of the utility pole, 6.00 m (19.7 ft) east of the removable pier platform, and
2.38 m (7.8 ft0 NNE of the south corner of the bulkhead.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8417208 PUBLICATION DATE: 02/27/2006
Name: RICHMOND, KENNEBEC RIVER
ME
NOAA Chart: 13298 Latitude: 44° 5.3' N ( 44.08830)
USGS Quad: GARDINER Longitude: 69° 47.9' W ( -69.79830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: MARCH 2 1896 FLOOD MARK
DESIGNATION: 841 7208 FLOOD MARK
MONUMENTATION: Bench Mark disk VM#: 17920
AGENCY: IDB PID#:
SETTING CLASSIFICATION: Brick wall OPUS PID:
LATITUDE: 44° 5.6' N ( 44.09330) LONGITUDE: 69° 47.9' W ( -69.79830)
The bench mark is a disk set in the bick wall of the Richmond Water Company
building located on Front Street, 17.00 m (55.8 ft) west of the easst corner of
the parking lot in the rear of the building, 15.35 m (50.4 ft) north of the
south corner of te parking lot, 6.69 m (22.0 ft) south of the east corner off
the Richmond Water Company Building, and 1.70 m (5.58 ft) above ground level.
BENCH MARK STAMPING: 7208 B 2005
DESIGNATION: 841 7208 B
MONUMENTATION: Tidal Station disk VM#: 17921
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 44° 5.2' N ( 44.08670) LONGITUDE: 69° 47.9' W ( -69.79830)
The bench mark is a disk set in a concrete monument located in Fort Richmond
Park near the water's edge, 27.41 m (89.9 ft) south of the south corner of the
Richmond Water Company building, 20.77 m (68.1 ft) SE of the bottom step leading
into the park, and 8.42 m (27.6 ft) NW of the NE corner of the walkway to a
floating dock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8417208 PUBLICATION DATE: 02/27/2006
Name: RICHMOND, KENNEBEC RIVER
ME
NOAA Chart: 13298 Latitude: 44° 5.3' N ( 44.08830)
USGS Quad: GARDINER Longitude: 69° 47.9' W ( -69.79830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7208 C 2005
DESIGNATION: 841 7208 C
MONUMENTATION: Tidal Station disk VM#: 17922
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete walkway OPUS PID:
LATITUDE: 44° 5.2' N ( 44.08670) LONGITUDE: 69° 48.0' W ( -69.80000)
The bench mark is a disk set in the concrete walkway for a floating dock located
at teh NE corner of the Fort Richmond Park parking lot, 50.27 m (164.9 ft) SE of
the entrance to Fort Richmond Park, 36.46 m (119.6 ft) south of the flag pole,
and 34.66 m (113.7 ft) ENE of the NE corner of the Richmond Contract Manufactory
Company.
BENCH MARK STAMPING: 31
DESIGNATION: 31
MONUMENTATION: Survey disk VM#: 17923
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: PE1169
SETTING CLASSIFICATION: Wall OPUS PID:
LATITUDE: 44° 5.3' N ( 44.08830) LONGITUDE: 69° 48.0' W ( -69.80000)
The bench mark is a disk set in the concrete wall of the Old Post Office, 14.40
m (47.2 ft) NNW of the centerline of Route 24 (Front Street), 7.24 (23.8 ft) SE
of the SW corner of the building, and 16.70 m (54.8 ft) wast of the handicap
ramp.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8417208 PUBLICATION DATE: 02/27/2006
Name: RICHMOND, KENNEBEC RIVER
ME
NOAA Chart: 13298 Latitude: 44° 5.3' N ( 44.08830)
USGS Quad: GARDINER Longitude: 69° 47.9' W ( -69.79830)
T I D A L D A T U M S
Tidal datums at RICHMOND, KENNEBEC RIVER based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: August 2005 - October 2005
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8418150 PORTLAND, CASCO BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 1.765
MEAN HIGH WATER MHW = 1.667
MEAN SEA LEVEL MSL = 0.904
MEAN TIDE LEVEL MTL = 0.861
MEAN LOW WATER MLW = 0.055
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
7208 A 2005 2.339 0.672
MARCH 2 1896 FLOOD MARK 5.570 3.903
7208 B 2005 2.794 1.127
7208 C 2005 2.861 1.194
31 9.786 8.119
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8417208 PUBLICATION DATE: 02/27/2006
Name: RICHMOND, KENNEBEC RIVER
ME
NOAA Chart: 13298 Latitude: 44° 5.3' N ( 44.08830)
USGS Quad: GARDINER Longitude: 69° 47.9' W ( -69.79830)
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.