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Datums Page Page 1 of 5
Station ID: 8638424 PUBLICATION DATE: 05/22/2013
Name: KINGSMILL, JAMES RIVER
VA
NOAA Chart: 12248 Latitude: 37° 13.2' N ( 37.22000)
USGS Quad: HOG ISLAND Longitude: 76° 39.8' W ( -76.66330)
To reach the tidal bench marks from the intersection of US Highway 60 and
Kingsmill Road in Williamsburg, proceed south along Kingsmill Road for 3.1 km
(1.9 mi) following the signs for Kingsmill Marina, then check in wth the
Harbormaster at the marina store. The bench marks are in the vicinity of the
marina and Kingsmill Road. The tide gauge was located on the southernmost dock
at the marina, just west of the center dock.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 8424 A 2003
DESIGNATION: 863 8424 A
MONUMENTATION: Tidal Station disk VM#: 17388
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Flange-encased rod OPUS PID:
LATITUDE: 37° 13.4' N ( 37.22330) LONGITUDE: 76° 39.7' W ( -76.66170)
The primary bench mark is frange-encased rod located on the grassy berm north of
the beach at the Kingsmill Marina boat ramp at the southern end of Kingsmill
Road, 14.60 m (47.90 ft) NE of the NE corner of the concrete ramp, 3.81 m (12.50
ft) SE of the corner curb a the south end of the road, and 0.3 m (1.0 ft) west
of a fiberglass witness post. The datum point is set 10 cm (0.3 ft) below the
ground, being that top of a stainless steel road driven 17.10 m (56.10 ft) to
refusal, in a sleeve extending to a depth of 0.9 m (3.0 ft), and encased in a 5
- inch NOS logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8638424 PUBLICATION DATE: 05/22/2013
Name: KINGSMILL, JAMES RIVER
VA
NOAA Chart: 12248 Latitude: 37° 13.2' N ( 37.22000)
USGS Quad: HOG ISLAND Longitude: 76° 39.8' W ( -76.66330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: KINGSMILL-3 1978
DESIGNATION: 863 8424 COE 3
MONUMENTATION: Survey disk VM#: 17389
AGENCY: US Corps of Engineers (USE) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 37° 13.4' N ( 37.22330) LONGITUDE: 76° 39.8' W ( -76.66330)
The bench mark is a disk set in the top of a concrete monument located on the
grassy berm NW of the beach at the Kingsmill Marina and east of the marina store
at the southern end of Kingsmill Road, 6.40 m (21.0 ft) east of light pole 38,
5.21 m (17.10ft) west of an 8' x 4.5' concrete slab with a park bench on it,
2.41 m (7.91 ft) south of the south edge of the sidewalk, and is set 0.10 m
(0.33 ft) below the ground.
BENCH MARK STAMPING: KINGSMILL-2 1978
DESIGNATION: 863 8424 COE 2
MONUMENTATION: Survey disk VM#: 17390
AGENCY: US Corps of Engineers (USE) IDB PID#:
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 37° 13.4' N ( 37.22330) LONGITUDE: 76° 39.8' W ( -76.66330)
The bench mark is a disk set in the top of a concrete monument located across
from Kindsmill Road and north of the marina store at the southern end of
Kingsmill Road, 16.0 m (52.50 ft) north of the flag pole at the store, 4.40 m
(14.44 ft) west of the parking lot curb, 1.80 m (5.90ft) east of light pole 34,
and 0.1 m (0.3 ft) below the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8638424 PUBLICATION DATE: 05/22/2013
Name: KINGSMILL, JAMES RIVER
VA
NOAA Chart: 12248 Latitude: 37° 13.2' N ( 37.22000)
USGS Quad: HOG ISLAND Longitude: 76° 39.8' W ( -76.66330)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: KINGSMILL-1 1978
DESIGNATION: 863 8424 COE 1
MONUMENTATION: Survey disk VM#: 17391
AGENCY: US Corps of Engineers (USE) IDB PID#:
SETTING CLASSIFICATION: Foundation OPUS PID:
LATITUDE: 37° 13.4' N ( 37.22330) LONGITUDE: 76° 39.7' W ( -76.66170)
The bench mark is a disk set in the west corner of the concrete foundation of
the sewerage pumping station located on the east side of Kingsmills Road just
north of the marina, 9.11 m (29.90 ft) NE of a fire hydrant, 5.21 m (17.10 ft)
south of the north corner of an 18' x 25' concrete foundation, 0.91 m (3.0 ft)
NW of the NW corner of the brick pump house, and 0.21 m (0.7 ft) about the
natural grade.
BENCH MARK STAMPING: 8424 C 2003
DESIGNATION: 863 8424 C
MONUMENTATION: Tidal Station disk VM#: 17393
AGENCY: National Ocean Service IDB PID#:
SETTING CLASSIFICATION: Concrete culvert wall OPUS PID:
LATITUDE: 37° 13.4' N ( 37.22330) LONGITUDE: 76° 39.9' W ( -76.66500)
The bench mark is a disk set in the top of a 1.5 m (5.0 ft) x .18 m (.6 ft) x .6
m (2.0 ft) concrete headwall storm water outlet located on the west side of
Kingsmill Road, 19.7 m (64.6 ft) SSE of light pole 31, 3.7 m (12.3 ft) east of
the centerline of the private road leading to plantation site, and 6.3 m (20.7
ft) SW of the centerline of Kingsmill Road.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8638424 PUBLICATION DATE: 05/22/2013
Name: KINGSMILL, JAMES RIVER
VA
NOAA Chart: 12248 Latitude: 37° 13.2' N ( 37.22000)
USGS Quad: HOG ISLAND Longitude: 76° 39.8' W ( -76.66330)
T I D A L D A T U M S
Tidal datums at KINGSMILL, JAMES RIVER based on:
LENGTH OF SERIES: 2 MONTHS
TIME PERIOD: July 2003 - August 2003
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8638610 SEWELLS POINT, HAMPTON ROADS
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.801
MEAN HIGH WATER MHW = 0.736
MEAN SEA LEVEL MSL = 0.393
MEAN TIDE LEVEL MTL = 0.392
MEAN LOW WATER MLW = 0.048
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
8424 A 2003 2.365 1.629
KINGSMILL-3 1978 4.558 3.822
KINGSMILL-2 1978 4.956 4.220
KINGSMILL-1 1978 4.186 3.450
8424 C 2003 10.969 10.233
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8638424 PUBLICATION DATE: 05/22/2013
Name: KINGSMILL, JAMES RIVER
VA
NOAA Chart: 12248 Latitude: 37° 13.2' N ( 37.22000)
USGS Quad: HOG ISLAND Longitude: 76° 39.8' W ( -76.66330)
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.
Station Location
Published bench mark
Unpublished bench mark
