U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8517201 PUBLICATION DATE: 01/13/2016
Name: NORTH CHANNEL BRIDGE, GRASSY B
NY
NOAA Chart: 12350 Latitude: 40° 38.7' N ( 40.64500)
USGS Quad: Jamaica Longitude: 73° 50.2' W ( -73.83670)
To reach the station from JFK airport in Queens, NY, proceed 2.1 km (1.3 mi)
north on the JFK Expressway, take the Belt Parkway West Exit and continue 5.2 km
(3.2 mi) west to Exit 17S for Cross Bay Boulevard, proceed south on Cross Bay
Boulevard 1.6 km (1.0 mi) to Old Mill Yacht Club at 16315 Cross Bay Boulevard
and the tide station on the seawall. The bench marks are on Old Mill Yacht Club
property, in the National Park Service Gateway National Recreation Area Spring
Creek location along 165th Avenue and along the Belt Parkway.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 7201 M 2015
DESIGNATION: 851 7201 M
MONUMENTATION: F VM#: 21365
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID#: BBDV03
LATITUDE: 40° 38.9' N ( 40.64867) LONGITUDE: 73° 50.3' W ( -73.83828)
The primary bench mark is a flange encased rod set in spring creek park S of
165th avenue, 47.01 m (154.2 ft) S of a traffic sign at the NW corner of 92nd st
and 165th avenue, 27.16 m (89.1 ft) S of a power pole SE of the intersection of
165th avenue and 92nd st, 26.52 m (87.0 ft) SSW of the W end of a guard rail E
of the access gate to the park and 12.16 m (39.9 ft) W of the center line of a
trail running S from 165th avenue. The bench mark is the top of a stainless
steel rod driven 28.0 m (91.9 ft) to refusal and encased in a 8 inch (20 cm) NOS
logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8517201 PUBLICATION DATE: 01/13/2016
Name: NORTH CHANNEL BRIDGE, GRASSY B
NY
NOAA Chart: 12350 Latitude: 40° 38.7' N ( 40.64500)
USGS Quad: Jamaica Longitude: 73° 50.2' W ( -73.83670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 7201 L 2015
DESIGNATION: 851 7201 L
MONUMENTATION: DB VM#: 21366
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Mat foundations OPUS PID:
LATITUDE: 40° 39.1' N ( 40.65167) LONGITUDE: 73° 50.2' W ( -73.83747)
The bench mark is a disk set in a concrete pad at the SE corner of the yacht
club parking lot, 23.91 m (78.4 ft) SSE of the SE corner of the old mill yacht
club on the W side of the wood deck, 13.07 m (42.9 ft) S of a light pole on the
E side of the parking lot N of the gangway to the floating dock, 2.73 m (9.0 ft)
NE of a 1.8m (6 ft) tall post where the fence transitions from a 1.2m (4 ft)
tall fence , 1.72 m (5.6 ft) NW of the SE corner of the chain link fence and
0.87 m (2.9 ft) E of the 20 cm (8 inch) diameter base of a large davit.
BENCH MARK STAMPING: 7201 N 2015
DESIGNATION: 851 7201 N
MONUMENTATION: F VM#: 21367
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID:
LATITUDE: 40° 38.9' N ( 40.64836) LONGITUDE: 73° 50.4' W ( -73.84008)
The bench mark is a flange encased rod set in the spring creek park area S of
165th avenue, 61.14 m (200.6 ft) SE of of a power pole on the N side of 165th
avenue between 89th street and 90th street, 51.19 m (167.9 ft) SSE of a fire
hydrant on the N side of 165th avenue W of the intersection with 90th street,
39.72 m (130.3 ft) S of the intersection of the centerlines of 165th avenue and
90th street and 31.61 m (103.7 ft) S of a wooden guy pole S of the intersection
of 165th avenue and 90th street. The bench mark is set 10 cm (4 inches) below
grade, being the top of a stainless steel rod driven 28.0 m (91.9 ft) to refusal
and encased in a 8-in (13 cm) NOS logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8517201 PUBLICATION DATE: 01/13/2016
Name: NORTH CHANNEL BRIDGE, GRASSY B
NY
NOAA Chart: 12350 Latitude: 40° 38.7' N ( 40.64500)
USGS Quad: Jamaica Longitude: 73° 50.2' W ( -73.83670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: U 352 1952
DESIGNATION: U 352
MONUMENTATION: DB VM#: 21368
AGENCY: US Coast & Geodetic Survey IDB PID#: KU1217
SETTING CLASSIFICATION: Abutments and piers of large bridges OPUS PID:
LATITUDE: 40° 39.9' N ( 40.66569) LONGITUDE: 73° 50.5' W ( -73.84178)
The bench mark is a disk set in the SW bridge abutment of the cross bay
boulevard bridge over the belt parkway, 18.26 m (59.9 ft) SSE of a light pole on
the W side of the bridge, 12.49 m (41.0 ft) NNW of pole number n70s4 which holds
a sign for the belt parkway, 10.61 m (34.8 ft) NW of a light pole and 0.60 m
(2.0 ft) WSW of the S end of an 8 ft (2.4 m) tall chain link fence.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8517201 PUBLICATION DATE: 01/13/2016
Name: NORTH CHANNEL BRIDGE, GRASSY B
NY
NOAA Chart: 12350 Latitude: 40° 38.7' N ( 40.64500)
USGS Quad: Jamaica Longitude: 73° 50.2' W ( -73.83670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: V 352 1952
DESIGNATION: V 352
MONUMENTATION: DB VM#: 21369
AGENCY: US Coast & Geodetic Survey IDB PID#: KU1218
SETTING CLASSIFICATION: Abutments and piers of large bridges OPUS PID:
LATITUDE: 40° 39.8' N ( 40.66256) LONGITUDE: 73° 50.9' W ( -73.84911)
The bench mark is a disk set vertically in the S wall on the E side of the
bridge, 23.52 m (77.2 ft) NE of S most vertical support beam for bridge on E
side of 84th street, 15.51 m (50.9 ft) W of the W most post for guardrail along
belt parkway on E side of bridge, 13.05 m (42.8 ft) NNW of the centerline of an
asphalt bike trail which runs parallel with the belt parkway, 10.41 m (34.2 ft)
N of manhole cover no 672 and 0.40 m (1.3 ft) above the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8517201 PUBLICATION DATE: 01/13/2016
Name: NORTH CHANNEL BRIDGE, GRASSY B
NY
NOAA Chart: 12350 Latitude: 40° 38.7' N ( 40.64500)
USGS Quad: Jamaica Longitude: 73° 50.2' W ( -73.83670)
T I D A L D A T U M S
Tidal datums at NORTH CHANNEL BRIDGE, GRASSY B based on:
LENGTH OF SERIES: 5 MONTHS
TIME PERIOD: April 2015 - August 2015
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8531680 SANDY HOOK
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 1.874
MEAN HIGH WATER MHW = 1.764
North American Vertical Datum NAVD88 = 1.044
MEAN SEA LEVEL MSL = 0.925
MEAN TIDE LEVEL MTL = 0.916
MEAN LOW WATER MLW = 0.068
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
7201 M 2015 4.423 2.659
7201 L 2015 3.204 1.440
7201 N 2015 4.028 2.264
U 352 1952 8.740 6.976
V 352 1952 5.581 3.817
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8517201 PUBLICATION DATE: 01/13/2016
Name: NORTH CHANNEL BRIDGE, GRASSY B
NY
NOAA Chart: 12350 Latitude: 40° 38.7' N ( 40.64500)
USGS Quad: Jamaica Longitude: 73° 50.2' W ( -73.83670)
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.