U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8635257 PUBLICATION DATE: 11/10/2010
Name: RAPPAHANNOCK BEND
VA
NOAA Chart: 12237 Latitude: 38° 12.8' N ( 38.21330)
USGS Quad: PORT ROYAL Longitude: 77° 14.6' W ( -77.24330)
To reach the tidal bench marks from the junction of highways 301 and 17 on the
south side of Port Royal, proceed northerly on route 301 for 3.9 km (2.4 mi)
crossing over the Rappahannock River to the crossroads, County Road 607 on the
left and County Road 625 on the right at a car dealership, turn left and go
northwesterly on County Road 607 (Port Conway Road) for 5.5 km (3.4 mi) to a
side road left at Dogue, turn left onto Cleve Road and go southerly for 2.7 km
(1.7 mi) to 6684 Vineyard Road on the right and the entrance to the Warner
Estate known as Rappahannock Bend, turn right at the double white brick columns,
go west on gravel driveway for 0.24 km (0.15 mi) to a "T", turn right and go
north for 0.32 (0.20 mi), then bear left and go west along the fence line on the
left for 0.32 km (0.20 mi), then bear left, continue southerly past the horse
stables and out buildings for 0.16 km (0.1 mi) to the caretaker's house and the
tide station at the bottom of the bank by the wood boat house, dock and ramp,
just west of the caretaker's house.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 5257 E 2007
DESIGNATION: 863 5257 E
MONUMENTATION: Metal Rod VM#: 18266
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBBH01
LATITUDE: 38° 12.9' N ( 38.21422) LONGITUDE: 77° 14.3' W ( -77.23878)
The primary bench mark is set in an open fenced pasture, 76.60 m (251.3 ft) SE
of bench mark 863 5257 D, 65.41 m (214.6 ft) east of the center door on the east
side of the horse barn, and 63.10 m (207.0 ft) south of the east-west white
painted fence on the north side of the pasture. The datum point is set 0.24 m
(0.80 ft) below the grade of the pasture, being the top of a rounded stainless
steel rod driven 12.2 m (40 ft) to refusal, and encased in an 18 cm (0.6 ft)
diameter NOS logo cap and the logo cap is 0.05 m (0.16 ft) below grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8635257 PUBLICATION DATE: 11/10/2010
Name: RAPPAHANNOCK BEND
VA
NOAA Chart: 12237 Latitude: 38° 12.8' N ( 38.21330)
USGS Quad: PORT ROYAL Longitude: 77° 14.6' W ( -77.24330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5257 A 2007
DESIGNATION: 863 5257 A
MONUMENTATION: Tidal Station disk VM#: 18267
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete post OPUS PID:
LATITUDE: 38° 12.8' N ( 38.21314) LONGITUDE: 77° 14.4' W ( -77.23975)
The bench mark is a disk set in the top of a 0.22 m (8.7 inch) diameter x 1.52 m
(5.0 ft) long concrete post, located in the back yard of the caretaker's house,
44.01 m (144.4 ft) SSW of bench mark 863 5257 B, 16.80 m (55.1 ft) north of the
north edge of the wood deck at the top of the stairs leading down to the
boathouse and dock, 11.70 m (38.4 ft) NW of the NW corner of the sunroom on the
caretaker's house, and 7.10 m (23.3 ft) east of the west edge of the yard and
the top of the bank leading down to the river.
BENCH MARK STAMPING: 5257 B 2007
DESIGNATION: 863 5257 B
MONUMENTATION: Tidal Station disk VM#: 18268
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete post OPUS PID:
LATITUDE: 38° 12.8' N ( 38.21347) LONGITUDE: 77° 14.4' W ( -77.23942)
The bench mark is set in the top of a 0.22 m (8.7 inch) diameter x 1.52 m (5.0
ft) long concrete post located near the low fence by the north end of a parking
area, north of the caretaker's house, 72.70 m (238.5 ft) south of bench mark 863
5257 C, 44.0 m (144.4 ft) NNE of bench mark 863 5257 A, 12.50 m (41.0 ft) west
of the wood fence painted white on the east side of the main driveway and west
side of the pasture, 6.60 m (21.7 ft) east of the centerline of a gravel
driveway on the west side of the parking area, 1.08 m (3.54 ft) NE of a low
wooden fence painted white at the north limit of the gravel parking area, and
0.03 m (1.2 inches) below the level of the lawn.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8635257 PUBLICATION DATE: 11/10/2010
Name: RAPPAHANNOCK BEND
VA
NOAA Chart: 12237 Latitude: 38° 12.8' N ( 38.21330)
USGS Quad: PORT ROYAL Longitude: 77° 14.6' W ( -77.24330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5257 C 2007
DESIGNATION: 863 5257 C
MONUMENTATION: Tidal Station disk VM#: 18269
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete slab OPUS PID:
LATITUDE: 38° 12.9' N ( 38.21428) LONGITUDE: 77° 14.4' W ( -77.23986)
The bench mark is set in the SE corner of a gently sloping concrete slab located
on the west side of the large doors on the main horse barn, north of the
caretaker's house, 72.70 m (238.5 ft) north of bench mark 863 5257 B, 4.00 m
(13.1 ft) east of the centerline of the gravel driveway, 2.31 m (7.6 ft) south
of the north edge of the slab, 0.37 m (1.21 ft) west of the west edge of the
barn, and 0.21 m (0.7 ft) north of the south edge of the slab.
BENCH MARK STAMPING: 5257 D 2007
DESIGNATION: 863 5257 D
MONUMENTATION: Tidal Station disk VM#: 18270
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete post OPUS PID:
LATITUDE: 38° 12.9' N ( 38.21475) LONGITUDE: 77° 14.4' W ( -77.23919)
The bench mark is set in the top of a 0.22 m (0.7 ft) diameter x 1.52 m (5.0 ft)
long concrete post, along the south side of the main gravel driveway by a gate
in the fence next to a small outbuilding, 76.60 m (251.3 ft) NW of bench mark
863 5257 E, 20.3 m (66.6 ft) east of the east side of a large wooden shed open
on the south side, 3.90 m (12.8 ft) NE of the NE wall of the most NE building by
the gate, and 0.06 m (0.2 ft) below the ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8635257 PUBLICATION DATE: 11/10/2010
Name: RAPPAHANNOCK BEND
VA
NOAA Chart: 12237 Latitude: 38° 12.8' N ( 38.21330)
USGS Quad: PORT ROYAL Longitude: 77° 14.6' W ( -77.24330)
T I D A L D A T U M S
Tidal datums at RAPPAHANNOCK BEND based on:
LENGTH OF SERIES: 10 MONTHS
TIME PERIOD: April 2008 - January 2009
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 = 0.740
MEAN HIGH WATER MHW = 0.691
MEAN SEA LEVEL MSL = 0.394
MEAN TIDE LEVEL MTL = 0.367
MEAN LOW WATER MLW = 0.044
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
5257 E 2007 8.916 8.225
5257 A 2007 8.710 8.019
5257 B 2007 8.155 7.464
5257 C 2007 8.764 8.073
5257 D 2007 9.692 9.001
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8635257 PUBLICATION DATE: 11/10/2010
Name: RAPPAHANNOCK BEND
VA
NOAA Chart: 12237 Latitude: 38° 12.8' N ( 38.21330)
USGS Quad: PORT ROYAL Longitude: 77° 14.6' W ( -77.24330)
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.