U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 4
PUBLICATION DATE: 11/08/1991
Station ID: 8512735 SUPERCEDED DATE: 04/21/2003
Name: SOUTH JAMESPORT, GREAT PECONIC BAY
NEW YORK
NOAA Chart: 12358 Latitude: 40° 56.1' N
USGS Quad: MATTITUCK Longitude: 72° 34.9' W
To reach the tidal bench marks from the intersection of State Highway 25 and
County Road 105 in Riverhead, proceed east on State Highway 25 for 3.0 miles
(4.8 km) to the village of Jamesport, then south on Washington Avenue for 0.8
mile (1.3 km) to Great Peconic Bay Marina on the right. The bench marks are
near the marina and nearby streets. The tide gage and staff were on the east
bulkhead of the marina entrance channel.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 2735 A 1988
MONUMENTATION: Survey Disk VM#: 2296
AGENCY: PID:
SETTING CLASSIFICATION: Stainless Steel Rod
The primary bench mark is near the NE corner of the entrance channel to Great
Peconic Bay Marina, at the west end of the Very Important Boat (V.I.B.) area of
the marina, 5.8 feet (1.8 m) east of the inside face of the east channel
bulkhead, and 4.2 feet (1.3 m) WNW of the NW corner of the parking lot.
BENCH MARK STAMPING: NO 1 1917
MONUMENTATION: Survey Disk VM#: 2295
AGENCY: PID#: KU0373
SETTING CLASSIFICATION: Granite Wall
The bench mark is set in the top of a low granite wall near the Great Peconic
Bay end of South Jamesport Avenue, 390 feet (119 m) south of the centerline of
Front Street, 43.3 feet (13.2 m) west of the southernmost 1.9- foot (0.6 m)
diameter poplar tree on the east side of South Jamesport Avenue, 28.4 feet (8.7
m) north of LIL power pole #53, and 21.2 feet (6.5 m) west of the centerline of
South Jamesport Avenue. NOTE: The edge of the disk away from the street is the
high point used for leveling.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 4
PUBLICATION DATE: 11/08/1991
Station ID: 8512735 SUPERCEDED DATE: 04/21/2003
Name: SOUTH JAMESPORT, GREAT PECONIC BAY
NEW YORK
NOAA Chart: 12358 Latitude: 40° 56.1' N
USGS Quad: MATTITUCK Longitude: 72° 34.9' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2735 B 1988
MONUMENTATION: Survey Disk VM#: 2297
AGENCY: PID:
SETTING CLASSIFICATION: Stainless Steel Rod
The bench mark is at the east end of V.I.B. area of the marina, 462 feet (141 m)
east of Bench Mark 2735 A 1988, 68.9 feet (21.0 m) west of the south gate
post at the east end of the V.I.B. area, 39.1 feet (11.9 m) south of the SE
corner pile of the marina, 4.8 feet (1.5 m) NE of the lowest crotch of a wild
cherry tree, and 2.5 feet (0.8 m) south of the center of a square wooden post.
BENCH MARK STAMPING: 2735 C 1988
MONUMENTATION: Survey Disk VM#: 2298
AGENCY: PID:
SETTING CLASSIFICATION: Stainless Steel Rod
The bench mark is near the first house along the beach east of the marina
entrance channel, 248.1 feet (75.6 m) ENE of the three pile cluster at the south
end of the east channel bulkhead, 42.6 feet (13.0 m) south of the SW corner of a
garage, 33.6 feet (10.2 m) NNW of the SW corner of the house, and 2.3 feet (0.7
m) east of a chain link fence.
BENCH MARK STAMPING: 2735 D 1988
MONUMENTATION: Survey Disk VM#: 2299
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Footing
The bench mark is set in the NW corner of the 1.4-foot (0.4 m) square concrete
footing for an abandoned wooden water tower, 63.0 feet (19.2 m) north of NYT
power pole #5, 23.7 feet (7.2 m) SE of the centerline of Center Street, 4.6 feet
(1.4 m) SE of a 6-foot (2 m) high chain link fence, 14.9 feet (4.5 m) SSE of a
1.8-foot (0.5 m) diameter maple tree, and 0.4 foot (0.1 m) above ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 4
PUBLICATION DATE: 11/08/1991
Station ID: 8512735 SUPERCEDED DATE: 04/21/2003
Name: SOUTH JAMESPORT, GREAT PECONIC BAY
NEW YORK
NOAA Chart: 12358 Latitude: 40° 56.1' N
USGS Quad: MATTITUCK Longitude: 72° 34.9' W
T I D A L D A T U M S
Tidal datums at SOUTH JAMESPORT, GREAT PECONIC BAY based on:
LENGTH OF SERIES: 12 MONTHS
TIME PERIOD: DECEMBER 1988-NOVEMBER 1989
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8510560 MONTAUK
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (10/22/1988) = 6.40
MEAN HIGHER HIGH WATER MHHW = 3.37
MEAN HIGH WATER MHW = 3.06
MEAN TIDE LEVEL MTL = 1.62
MEAN LOW WATER MLW = 0.18
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (02/09/1989) = -1.72
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
2735 A 1988 7.09 4.03
NO 1 1917 6.27 3.21
2735 B 1988 7.59 4.53
2735 C 1988 7.69 4.63
2735 D 1988 10.84 7.78
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 4
PUBLICATION DATE: 11/08/1991
Station ID: 8512735 SUPERCEDED DATE: 04/21/2003
Name: SOUTH JAMESPORT, GREAT PECONIC BAY
NEW YORK
NOAA Chart: 12358 Latitude: 40° 56.1' N
USGS Quad: MATTITUCK Longitude: 72° 34.9' 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.