U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8632837 PUBLICATION DATE: 10/14/2011
Name: RAPPAHANNOCK LIGHT
VA
NOAA Chart: 12226 Latitude: 37° 32.3' N ( 37.53830)
USGS Quad: WEST OF JAMESVILLE Longitude: 76° 0.9' W ( -76.01500)
To reach the tide station by boat, from Deltaville Marina at 274 Bucks View
Lane, Deltaville, Virginia (on the north side of Jackson Creek) proceed out of
the protected harbor via the marked channel for 0.96 km (0.5 nm) to the F G 4s15
ft buoy. From this buoy travel easterly for 27.1 km (14.6 nm) to the
Rappahannock Light Front Range and the location of the tide station.
Alternately, this light structure can be reached by boat, from Silver Beach (on
the eastern shore of Virginia) and proceeding NW for 13.0 km (7.0 nm). There is
a boat landing on the SW side of the monopod light structure, with a grating
about 2 meters above the water. It can be difficult to get onto the structure
in rough conditions. The face of the landing area is oriented NW-SE (along the
range line) and the tidal current generally runs north on the flood and south on
the ebb. The bench marks are part of the steel platform.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 2837 A 2006
DESIGNATION: 863 2837 A
MONUMENTATION: Metal Rod VM#: 18248
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Metal roof OPUS PID:
LATITUDE: 37° 32.3' N ( 37.53830) LONGITUDE: 76° 0.9' W ( -76.01500)
The primary bench mark is the top of a 0.11 m (0.47 ft) long 5/8 inch diameter
threaded rod with a chiseled cross securely bolted to the top northern corner of
a metal covered roof which protects the range lights on the NW side of the upper
structure of the light, 2.50 m (8.2 ft) NE of the small white navigation light
at the westerly corner of the metal roof, 2.24 m (7.4 ft) NW of the northerly
corner of the fiberglass building, 1.87 m (6.1 ft) south of the northerly most
corner of the upper platform, 0.09 m (0.3 ft) south of the northern most corner
of the metal roof, approximately 9.5 m (31 ft) above the water, 2.30 m (7.5 ft)
above the upper deck grating, and 0.05 m (0.16 ft) above the stainless steel
underlayment to the corrugated metal roof.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8632837 PUBLICATION DATE: 10/14/2011
Name: RAPPAHANNOCK LIGHT
VA
NOAA Chart: 12226 Latitude: 37° 32.3' N ( 37.53830)
USGS Quad: WEST OF JAMESVILLE Longitude: 76° 0.9' W ( -76.01500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2837 B 2006
DESIGNATION: 863 2837 B
MONUMENTATION: See descriptive text VM#: 18249
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Structural platform OPUS PID:
LATITUDE: 37° 32.3' N ( 37.53830) LONGITUDE: 76° 0.9' W ( -76.01500)
The bench mark is top of a welded high spot at the apex of a "L" shaped scribe
mark in the steel on the structural part of the upper platform at the easterly
corner of the ladder and man cage, 5.02 m (16.5 ft) NW from the southern corner
of the upper structure, 2.80 m (9.2 ft) SE of the manual hand crank crane
support, 1.32 m (4.3 ft) SE of the westerly most corner of the fiberglass
building, 1.01 m (3.3 ft) east of the west edge of the ladder leading to the
lower platform, and 0.03 m (0.10 ft) below the level of the deck grating.
BENCH MARK STAMPING: 2837 C 2006
DESIGNATION: 863 2837 C
MONUMENTATION: Chiseled Cross VM#: 18250
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Steel fender pipe OPUS PID:
LATITUDE: 37° 32.3' N ( 37.53830) LONGITUDE: 76° 0.8' W ( -76.01330)
The bench mark is a chiseled cross stamped into the highest part on the top of a
round steel fender pipe (center of five) each with a hard black rubber strip on
the seaward side on the SW side of the lower boat landing platform of the light
structure, 2.16 m (7.1 ft) SW of the SW edge of the main support piling and
bench mark 2837 E 2007, 1.67 m (5.5 ft) SE of the center of the northwesterly
most fender pipe, 1.66 m (5.4 ft) NW of bench mark 2837 D 2007, 0.92 m (3.02 ft)
south of the west edge of the ladder leading to the upper platform, and 0.53 m
(1.7 ft) above the level of the steel grating floor of the lower platform.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8632837 PUBLICATION DATE: 10/14/2011
Name: RAPPAHANNOCK LIGHT
VA
NOAA Chart: 12226 Latitude: 37° 32.3' N ( 37.53830)
USGS Quad: WEST OF JAMESVILLE Longitude: 76° 0.9' W ( -76.01500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2837 D 2007
DESIGNATION: 863 2837 D
MONUMENTATION: Chiseled Cross VM#: 18428
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Steel fender pipe OPUS PID:
LATITUDE: 37° 32.3' N ( 37.53830) LONGITUDE: 76° 0.8' W ( -76.01330)
The bench mark is a chiseled cross stamped into the highest part on the top of a
round steel fender pipe (SE most of five) each with a hard black rubber strip on
the seaward side on the SW side of the lower boat landing platform of the light
structure, 3.34 m (10.96 ft) SE of the center of the NW'ly most fender pipe,
2.72 m (8.92 ft) S of bench mark 2837 E 2007, 1.66 m (5.45 ft) SE of bench mark
2837 C 2006, and 0.55 m (1.8 ft) above the level of the steel grating floor of
the lower platform.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8632837 PUBLICATION DATE: 10/14/2011
Name: RAPPAHANNOCK LIGHT
VA
NOAA Chart: 12226 Latitude: 37° 32.3' N ( 37.53830)
USGS Quad: WEST OF JAMESVILLE Longitude: 76° 0.9' W ( -76.01500)
T I D A L D A T U M S
Tidal datums at RAPPAHANNOCK LIGHT based on:
LENGTH OF SERIES: 4 MONTHS
TIME PERIOD: June 2007 - September 2007
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8636580 WINDMILL POINT, RAPPAHANNOCK RIVER
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.571
MEAN HIGH WATER MHW = 0.519
MEAN SEA LEVEL MSL = 0.287
MEAN TIDE LEVEL MTL = 0.279
MEAN LOW WATER MLW = 0.040
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
2837 A 2006 12.240 11.721
2837 B 2006 9.863 9.344
2837 C 2006 2.489 1.970
2837 D 2007 2.480 1.961
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8632837 PUBLICATION DATE: 10/14/2011
Name: RAPPAHANNOCK LIGHT
VA
NOAA Chart: 12226 Latitude: 37° 32.3' N ( 37.53830)
USGS Quad: WEST OF JAMESVILLE Longitude: 76° 0.9' W ( -76.01500)
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.