U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 07/17/1989
Station ID: 8464041 SUPERCEDED DATE: 04/21/2003
Name: MADISON, MADISON BEACH CLUB, LONG ISLAND SOUND
CONNECTICUT
NOAA Chart: 12374 Latitude: 41° 16.2' N
USGS Quad: CLINTON Longitude: 72° 36.2' W
To reach the tidal bench marks from Interstate 95 at State Road 79 (exit 61),
proceed south on State Road 79 to U.S. Highway 1, then east 0.25 mile (0.40
km) on U.S. Highway 1 to Island Avenue, then south on Island Avenue to the end
at Madison Beach Club. The bench marks are along Island Avenue, Middle Beach
Road, and at Madison Beach Club. The tide gage and staff were on the beach
clubs wooden pier.
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2 1931
MONUMENTATION: Survey Disk VM#: 2252
AGENCY: PID#: LX0451
SETTING CLASSIFICATION: Stone Pier
The bench mark is set in the top capping stone of the eastern edge of the stone
pier at Madison Beach Club, 64.0 feet (19.5 m) north of the south end of the
stone portion of the pier, 28.0 feet (8.5 m) south of the southernmost stone
fence post, and 2.4 feet (0.7 m) west of the east edge of the pier.
BENCH MARK STAMPING: P 36 1965
MONUMENTATION: Survey Disk VM#: 2253
AGENCY: PID#: LX0452
SETTING CLASSIFICATION: Concrete Sea Wall
The bench mark is set in the top of the north end of a 2-foot (1 m) wide
concrete wall which projects northward from a sea wall about 0.1 mile (0.2 km)
east of Madison Beach Club along Middle Beach Road, south of the intersection of
Tuxis and Middle Beach Roads, 56.5 feet (17.2 m) west of a fire hydrant, 39.0
feet (11.9 m) SSW of the center of the intersection, 24.7 feet (7.5 m) south of
Connecticut Light and Power Pole #4446, and 19.0 feet (5.8 m) north of the
seaward edge of the sea wall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 07/17/1989
Station ID: 8464041 SUPERCEDED DATE: 04/21/2003
Name: MADISON, MADISON BEACH CLUB, LONG ISLAND SOUND
CONNECTICUT
NOAA Chart: 12374 Latitude: 41° 16.2' N
USGS Quad: CLINTON Longitude: 72° 36.2' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: Q 36 1965
MONUMENTATION: Survey Disk VM#: 2254
AGENCY: PID#: LX0450
SETTING CLASSIFICATION: Rock Outcrop
The bench mark is set in the top of a rock ledge which is about 10 feet (3 m)
long and 1 foot (0.3 m) high and mostly covered with dirt, on the east side of
Island Avenue approximately 0.2 mile (0.3 km) south of U.S. Highway 1 and south
of the northernmost of two pair of large stone driveway entrance posts, 74.4
feet (22.7 m) SE of and across Island Avenue from a fire hydrant, 69.0 feet
(21.0 m) SE of the centerline of the northernmost driveway, 22.9 feet (7.0 m)
east of the centerline of Island Avenue, 6.2 feet (1.9 m) ENE of a school
crossing sign, and 1 foot (0.3 m) above the street.
BENCH MARK STAMPING: 4041 A 1988
MONUMENTATION: Survey Disk VM#: 2255
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Headwall
The bench mark is set in a concrete headwall for a culvert beneath Island
Avenue, 0.4 mile (0.6 km) north of Madison Beach Club, 20 feet (6 m) west of the
centerline of Island Avenue, 7.1 feet (2.2 m) SSW of power pole #3323, and 6.6
feet (2.0 m) north of the south end of the headwall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 07/17/1989
Station ID: 8464041 SUPERCEDED DATE: 04/21/2003
Name: MADISON, MADISON BEACH CLUB, LONG ISLAND SOUND
CONNECTICUT
NOAA Chart: 12374 Latitude: 41° 16.2' N
USGS Quad: CLINTON Longitude: 72° 36.2' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4041 B 1988
MONUMENTATION: Survey Disk VM#: 2256
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Sea Wall
The bench mark is set in a 4.4-foot (1.3 m) wide concrete sea wall at Madison
Beach Club, 67.8 feet (20.7 m) NW of the SW corner of the east wing porch, 63.8
feet (19.4 m) SW of the south corner of the main building porch, 2.1 feet (0.6
m) NE of the SW face of the sea wall, and 1.7 feet (0.5 m) SE of the NW face of
the sea wall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 07/17/1989
Station ID: 8464041 SUPERCEDED DATE: 04/21/2003
Name: MADISON, MADISON BEACH CLUB, LONG ISLAND SOUND
CONNECTICUT
NOAA Chart: 12374 Latitude: 41° 16.2' N
USGS Quad: CLINTON Longitude: 72° 36.2' W
T I D A L D A T U M S
Tidal datums at MADISON, MADISON BEACH CLUB, LONG ISLAND SOUND based on:
LENGTH OF SERIES: 89 HIGH & LOW WATERS
TIME PERIOD: MARCH 17 - MAY 1, 1988
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8467150 BRIDGEPORT
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (04/15/1988) = 6.76
MEAN HIGHER HIGH WATER MHHW = 5.49
MEAN HIGH WATER MHW = 5.18
MEAN TIDE LEVEL MTL = 2.71
* NATIONAL GEODETIC VERTICAL DATUM NGVD29 = 2.08
MEAN LOW WATER MLW = 0.23
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (03/21/1988) = -1.63
* NGVD reference based on elevations published in Quad 410723, 1968, and NOS
leveling of 1989.
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
2 1931 10.31 5.13
P 36 1965 10.13 4.95
Q 36 1965 32.91 27.73
4041 A 1988 15.14 9.96
4041 B 1988 10.92 5.74
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 07/17/1989
Station ID: 8464041 SUPERCEDED DATE: 04/21/2003
Name: MADISON, MADISON BEACH CLUB, LONG ISLAND SOUND
CONNECTICUT
NOAA Chart: 12374 Latitude: 41° 16.2' N
USGS Quad: CLINTON Longitude: 72° 36.2' 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.