U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 07/30/1999
Station ID: 8572467 SUPERCEDED DATE: 04/21/2003
Name: KENT POINT, CHESAPEAKE BAY
MARYLAND
NOAA Chart: 12266 Latitude: 38° 50.2' N
USGS Quad: CLAIBORNE Longitude: 76° 22.4' W
To reach the tidal bench marks from the intersection of U.S. Highways 50/301 and
State Highway 8 on Kent Island east of the Chesapeake Bay Bridge, proceed south
on State Highway 8 for 11.6 km (7.2 mi) to Kent Point Road, turn right and go
south on Kent Point Road for 6.6 km (4.1 mi) to Short Road, then turn right and
continue on Short Road to the parking lot of the Kent Point Marina. The bench
marks are located on the marina property and to the private residence to the
east. The tide gage was located at the east end of the bulkhead on the west side
of the entrance to the marina.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 2467 B 1996
DESIGNATION: 857 2467 B
MONUMENTATION: Bench Mark disk VM#: 13440
AGENCY: National Ocean Service (NOS) PID:
SETTING CLASSIFICATION: Concrete loading dock
The primary bench mark is a disk set in a concrete loading dock at the J & L
Bait Company building on the east side of the Kent Point Marina, 24.1 m (79 ft)
ENE of power pole 24952-10591 D.P.L., 5.18 m (17.5 ft) south of the north edge
of the loading dock, and 0.18 m (0.6 ft) east of the west edge of the loading
dock.
BENCH MARK STAMPING: 2467 A 1996
DESIGNATION: 857 2467 A
MONUMENTATION: Bench Mark disk VM#: 13439
AGENCY: National Ocean Service (NOS) PID:
SETTING CLASSIFICATION: Concrete pad
The bench mark is a disk set in a concrete pad adjacent to the sea wall forming
the SE corner of the Kent Point Marina boat basin, 5.94 m (19.5 ft) ENE of light
pole No. 17 at the SE corner of the basin, 0.55 m (1.8 ft) south of the face of
the bulkhead, and 0.30 m (1.0 ft) west of the east edge of the concrete pad.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 07/30/1999
Station ID: 8572467 SUPERCEDED DATE: 04/21/2003
Name: KENT POINT, CHESAPEAKE BAY
MARYLAND
NOAA Chart: 12266 Latitude: 38° 50.2' N
USGS Quad: CLAIBORNE Longitude: 76° 22.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2467 C 1996
DESIGNATION: 857 2467 C
MONUMENTATION: Bench Mark disk VM#: 13441
AGENCY: National Ocean Service (NOS) PID:
SETTING CLASSIFICATION: Concrete pad
The bench mark is a disk set in a concrete pad forming the base of the air
conditioning units behind the J & L Bait Company building on the east side of
the Kent Point marina boat basin, 12.8 m (42 ft) west of the centerline of a
gravel road leading to the Willard residence to the east, 5.18 m (17.0 ft) NE of
the SE corner of the bait house, and 0.76 m (2.5 ft) south of the north edge of
the concrete pad.
BENCH MARK STAMPING: 2467 D 1996
DESIGNATION: 857 2467 D
MONUMENTATION: Bench Mark disk VM#: 13442
AGENCY: National Ocean Service (NOS) PID:
SETTING CLASSIFICATION: Concrete pad
The bench mark is a disk set in a concrete pad that is the base for a 4 m (12
ft) diameter satellite television dish along the entrance road to the Willard
residence east of the Kent Point Marina, 23.62 m (77.5 ft) SW of power pole
25042-10538 D.P.L., 10.1 m (33 ft) SE of a brick culvert on the north side of
the gravel entrance road, and 0.3 m (1 ft) NE of the satellite dish mast.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 07/30/1999
Station ID: 8572467 SUPERCEDED DATE: 04/21/2003
Name: KENT POINT, CHESAPEAKE BAY
MARYLAND
NOAA Chart: 12266 Latitude: 38° 50.2' N
USGS Quad: CLAIBORNE Longitude: 76° 22.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: BELL 1 1933
DESIGNATION: BELL
MONUMENTATION: Reference Mark disk VM#: 13443
AGENCY: NGS or CGS (USC&GS) PID#: AI4153
SETTING CLASSIFICATION: Concrete Monument
The bench mark is a reference mark disk set in a concrete monument, 36.3 m (119
ft) north of the north edge of the rip-rap shoreline, 15.8 m (52 ft) NE of the
north edge of an above-ground 500 gallon fuel tank, and 0.15 m (0.5 ft) north of
a metal witness post.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 07/30/1999
Station ID: 8572467 SUPERCEDED DATE: 04/21/2003
Name: KENT POINT, CHESAPEAKE BAY
MARYLAND
NOAA Chart: 12266 Latitude: 38° 50.2' N
USGS Quad: CLAIBORNE Longitude: 76° 22.4' W
T I D A L D A T U M S
Tidal datums at KENT POINT, CHESAPEAKE BAY based on:
LENGTH OF SERIES: 31 MONTHS
TIME PERIOD: June 1996 - December 1998
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8575512 U.S. NAVAL ACADEMY, SEVERN R., CHES. BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (09/07/1996) = 1.539
MEAN HIGHER HIGH WATER MHHW = 0.475
MEAN HIGH WATER MHW = 0.399
MEAN SEA LEVEL MSL = 0.240
MEAN TIDE LEVEL MTL = 0.237
MEAN LOW WATER MLW = 0.074
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (04/01/1997) = -0.732
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
2467 B 1996 2.526 2.127
2467 A 1996 1.391 0.992
2467 C 1996 2.229 1.830
2467 D 1996 2.887 2.488
BELL 1 1933 3.186 2.787
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 07/30/1999
Station ID: 8572467 SUPERCEDED DATE: 04/21/2003
Name: KENT POINT, CHESAPEAKE BAY
MARYLAND
NOAA Chart: 12266 Latitude: 38° 50.2' N
USGS Quad: CLAIBORNE Longitude: 76° 22.4' 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.