U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 7
PUBLICATION DATE: 03/28/1988
Station ID: 8572770 SUPERCEDED DATE: 04/21/2003
Name: MATAPEAKE, CHESAPEAKE BAY
MARYLAND
NOAA Chart: 12270 Latitude: 38° 57.4' N
USGS Quad: KENT ISLAND Longitude: 76° 21.3' W
To reach the tidal bench marks from the intersection of U.S. Highway 50 and
State Highway 8 on Kent Island, proceed south on State Highway 8 for 2.4 miles
(3.9 km) to the access road for Chesapeake Bay Model, Matapeake Marine Terminal,
and the Maryland Department of Natural Resources Police facilities, turn right
and go west for 0.4 mile (0.6 km) to the police facilities area. The bench
marks are located on the police facilities grounds, at the intersection of State
Highway 8 and the access road, and at the entrance gate to Matapeake Marine
Terminal. The tide gage and staff were located on the police facilities central
pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1972
MONUMENTATION: Survey Disk VM#: 10828
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Sea Wall
The bench mark is set flush in a concrete sea wall, in the SE corner of south-
ern extension of the police facilities central pier, 44.0 feet (13.4 m) south of
the centerline of the pier, 31.3 feet (9.5 m) east of the SW corner of the deck
on the southern side of the pier, 4.5 feet (1.4 m) SW of the most northerly
chain link fence post on the southerly side of the pier, and 0.6 feet (0.2 m)
above the parking lot.
BENCH MARK STAMPING: X 126 1971
MONUMENTATION: Survey Disk VM#: 10826
AGENCY: PID#: HV0185
SETTING CLASSIFICATION: Copper-clad Steel Rod
The bench mark is at the intersection of State Highway 8 and the access road,
108.0 feet (32.9 m) NW of the centerline of the highway, 2.0 feet (0.6 m) SW of
a metal witness post and 1.0 foot (0.3 m) SW of pole #11 F. The bench mark is
level with the ground, crimped to a copper-clad steel rod driven 80 feet (24 m)
to refusal and encased in a 6-inch metal pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
PUBLICATION DATE: 03/28/1988
Station ID: 8572770 SUPERCEDED DATE: 04/21/2003
Name: MATAPEAKE, CHESAPEAKE BAY
MARYLAND
NOAA Chart: 12270 Latitude: 38° 57.4' N
USGS Quad: KENT ISLAND Longitude: 76° 21.3' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: Y 126 1971
MONUMENTATION: Survey Disk VM#: 10827
AGENCY: PID#: HV0186
SETTING CLASSIFICATION: Copper-clad Steel Rod
The bench mark is located north of the police facilities area in a clearing in
the woods at the remnants of a radio tower foundation, 132.0 feet (40.2 m) NE of
a chain link fence, 21.0 feet (6.4 m) SW of the centerline of a path, and 1.4
feet (0.4 m) NW of a metal witness post. The bench mark is level with the
ground, crimped to a copper clad steel rod driven 76 feet (23 m) to refusal and
encased in a 4-inch metal pipe.
BENCH MARK STAMPING: NO 2 1972
MONUMENTATION: Survey Disk VM#: 10829
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Step
The bench mark is set flush in the second concrete step leading from the
abandoned ferry landing to the warehouse, 43.0 feet (13.1 m) NE of the flagpole
on the police facilities grounds, 40.9 feet (12.5 m) SW of the SW curbing
surrounding police boats and the warehouse, 5.6 feet (1.7 m) SE of the most NW
point of the stairs leading to the warehouse, and 0.3 foot (0.1 m) above the
sidewalk.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
PUBLICATION DATE: 03/28/1988
Station ID: 8572770 SUPERCEDED DATE: 04/21/2003
Name: MATAPEAKE, CHESAPEAKE BAY
MARYLAND
NOAA Chart: 12270 Latitude: 38° 57.4' N
USGS Quad: KENT ISLAND Longitude: 76° 21.3' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 3 1972
MONUMENTATION: Survey Disk VM#: 10830
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Culvert
The bench mark is set flush in a concrete culvert that empties rain water from
the warehouse, 106.4 feet (32.4 m) east of the NW corner of the brick warehouse,
73.3 feet (22.3 m) NE of the NE corner of the brick warehouse, 46.3 feet (14.1
m) SW of the southerly side or edge of the parking area surrounding the police
barracks, and 0.8 foot (0.2 m) below the ground.
BENCH MARK STAMPING: NO 6 1973
MONUMENTATION: Survey Disk VM#: 10831
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Step
The bench mark is set flush in the top step of the steps leading from the
headquarters to the warehouse, 102.6 feet (31.3 m) SW of the NW corner of the
warehouse, 66.5 feet (20.3 m) NW of the SW corner of the warehouse, 18.5 feet
(5.6 m) NW of the flagpole, and 0.2 feet (0.1 m) below the ground.
BENCH MARK STAMPING: 2770 A 1979
MONUMENTATION: Survey Disk VM#: 10832
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Pier Cap
The bench mark is set flush in the NW corner of the central concrete pier
section, 81.4 feet (24.8 m) west of the inshore end of pier, 14.1 feet (4.3 m)
north of the centerline of the pier, and 1.4 feet (0.4 m) NW of a lamp post.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
PUBLICATION DATE: 03/28/1988
Station ID: 8572770 SUPERCEDED DATE: 04/21/2003
Name: MATAPEAKE, CHESAPEAKE BAY
MARYLAND
NOAA Chart: 12270 Latitude: 38° 57.4' N
USGS Quad: KENT ISLAND Longitude: 76° 21.3' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2770 B 1979
MONUMENTATION: Survey Disk VM#: 10833
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Transformer Foundation
The bench mark is set flush in the SE corner of a 6 x 6 foot (2 x 2 m) concrete
slab supporting an electric transformer at the main gate entrance to Matapeake
Marine Terminal, 22.5 feet (6.9 m) west of the centerline of the entrance road
to the police facilities, 18.5 feet (5.6 m) NW of the west gate post, 1.0 foot
(0.3 m) SE of the SE corner of the transformer, and 0.6 foot (0.2 m) above the
ground.
BENCH MARK STAMPING: NO STAMPING 1
MONUMENTATION: Vertical Bolt VM#: 10834
AGENCY: PID:
SETTING CLASSIFICATION: Fire Hydrant
The bench mark is the top of the vertical bolt between the casting letters
ANNISTON*ALABAMA,on the east side of the top of the collar of the fire hydrant
on the north side of the police facilities parking lot, 129.1 feet (39.3 m) SE
of the SE corner of the headquarters, 59.0 feet (18.0 m) north of the most NE of
westerly median in center of the parking area for the police barracks and the
headquarters, 17.3 feet (5.3 m) NW of the centerline of the paved driveway
leading north to the DNR Police Academy wood frame building, and 1.6 feet (0.5
m) above the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
PUBLICATION DATE: 03/28/1988
Station ID: 8572770 SUPERCEDED DATE: 04/21/2003
Name: MATAPEAKE, CHESAPEAKE BAY
MARYLAND
NOAA Chart: 12270 Latitude: 38° 57.4' N
USGS Quad: KENT ISLAND Longitude: 76° 21.3' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO STAMPING 2
MONUMENTATION: Vertical Nut VM#: 10835
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Foundation
The bench mark is the top of the vertical nut securing the radio antenna to the
most easterly concrete foundation on the police facilities grounds, the nut is
the second one clockwise from the antenna brace, and the first nut counter
clockwise from the metal ground of the antenna support, 79.8 feet (24.3 m) SSE
of the NE corner of the DNR Police Academy building, 39.0 feet (11.9 m) SE of
the SE corner of the DNR Police Academy building, 6.0 feet (1.8 m) south of the
north side of a fence around transmitting tower, and 0.9 feet (0.3 m) above the
ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
PUBLICATION DATE: 03/28/1988
Station ID: 8572770 SUPERCEDED DATE: 04/21/2003
Name: MATAPEAKE, CHESAPEAKE BAY
MARYLAND
NOAA Chart: 12270 Latitude: 38° 57.4' N
USGS Quad: KENT ISLAND Longitude: 76° 21.3' W
T I D A L D A T U M S
Tidal datums at MATAPEAKE, CHESAPEAKE BAY based on:
LENGTH OF SERIES: 10 YEARS
TIME PERIOD: 1973-1983
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8574680 BALTIMORE
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (03/19/1983) = 3.76
MEAN HIGHER HIGH WATER MHHW = 1.49
MEAN HIGH WATER MHW = 1.22
MEAN TIDE LEVEL MTL = 0.73
* NATIONAL GEODETIC VERTICAL DATUM NGVD29 = 0.35
MEAN LOW WATER MLW = 0.23
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (04/05/1975) = -3.37
* NGVD reference based on elevations published in Quad 380761, 1982, and NOS
leveling of 1984.
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
NO 1 1972 7.75 6.53
X 126 1971 15.86 14.64
Y 126 1971 18.88 17.66
NO 2 1972 9.11 7.89
NO 3 1972 15.55 14.33
NO 6 1973 16.26 15.04
2770 A 1979 7.79 6.57
2770 B 1979 22.72 21.50
NO STAMPING 1 13.50 12.28
NO STAMPING 2 21.00 19.78
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
PUBLICATION DATE: 03/28/1988
Station ID: 8572770 SUPERCEDED DATE: 04/21/2003
Name: MATAPEAKE, CHESAPEAKE BAY
MARYLAND
NOAA Chart: 12270 Latitude: 38° 57.4' N
USGS Quad: KENT ISLAND Longitude: 76° 21.3' 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.