Bench mark positions only appear on the map if their coordinates in the CO-OPS database are at the precision of degrees/minutes/seconds/and tenths of seconds. If the coordinates are less precise, the mark will not appear.

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                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
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.