Bench Mark Sheet for 8571091, CRISFIELD MD

Superseded Epoch

Large map location marker Station Location
Small red map location marker Published bench mark
Small blue map location marker Unpublished bench mark

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.

Printable version

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                                                
Station ID: 8571091                         PUBLICATION DATE:  09/05/2013
Name:       CRISFIELD                                         
            MD
NOAA Chart: 12231                           Latitude:   37° 58.6' N (  37.97670)
USGS Quad:  CRISFIELD                       Longitude:  75° 51.8' W ( -75.86330)


To reach the tidal bench marks from Salisbury, Maryland, proceed 32 km (20 mi)
south on U.S. Route 13 to Maryland Route 413, then 18 km (11 mi) SE on Route 413
to the Town of Crisfield, then to the end of Main Street in Crisfield and the
city wharf and warehouse on the Little Annemessex River.  The bench marks are
located in the vicinity of Main Street to the NE of the wharf.  The tide gage
and staff were located on the south corner of the city wharf behind the
warehouse.


                         T I D A L   B E N C H   M A R K S


                 PRIMARY BENCH MARK STAMPING:  NO 10 1942
                         DESIGNATION:          857 1091 TIDAL 10

MONUMENTATION:           Tidal Station disk                    VM#:         3043
AGENCY:                  US Coast & Geodetic Survey
                         (USC&GS)                                 IDB PID#:  FW0499
SETTING CLASSIFICATION:  Concrete block                        OPUS PID:        
LATITUDE:   37° 58.7' N (  37.97830)          LONGITUDE:  75° 51.8' W ( -75.86330)


The primary bench mark is a disk set in the center of the NW side of a concrete
block, at the intersection of Broad and 11th Streets, 40.0 m (131.2 ft)  SW of
the center of 11th Street, 8.0 m (26.2 ft) SE of and level with the center of
Broad Street, 7.60 m (24.9 ft) NE of utility pole No. 39150 79114, 0.4 m (1.3
ft) NW of the north corner of a building, and flush with the ground surface.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                                                
Station ID: 8571091                         PUBLICATION DATE:  09/05/2013
Name:       CRISFIELD                                         
            MD
NOAA Chart: 12231                           Latitude:   37° 58.6' N (  37.97670)
USGS Quad:  CRISFIELD                       Longitude:  75° 51.8' W ( -75.86330)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  1091 A
                         DESIGNATION:          857 1091 A TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         3038
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Concrete foundation                   OPUS PID:        
LATITUDE:   37° 58.6' N (  37.97670)          LONGITUDE:  75° 51.9' W ( -75.86500)


The bench mark is a disk set in the concrete foundation of the Captain's Galley
Restaurant on the waterfront in Crisfield, Maryland, 13.05 m (42.8 ft) north of
the SW corner of the building, 10 m (33 ft) south of the Main Street edge, and
in the NW corner of the restaurant 0.64 m (2.1 ft) from the west seawall.



                         BENCH MARK STAMPING:  1091 B
                         DESIGNATION:          857 1091 B TIDAL

MONUMENTATION:           Tidal Station disk                    VM#:         3039
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:  DH7941
SETTING CLASSIFICATION:  Concrete road divider                 OPUS PID#: DH7941
LATITUDE:   37° 58.6' N (  37.97670)          LONGITUDE:  75° 51.9' W ( -75.86500)


The bench mark is a disk set flush in a concrete road divider located on Main
Street, two blocks from the waterfront on the east end of the road divider, and
15.85 m (52.0 ft) south of the entrance to the L. Forbush & Sons Hardware
Company.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  5

                                                                                
Station ID: 8571091                         PUBLICATION DATE:  09/05/2013
Name:       CRISFIELD                                         
            MD
NOAA Chart: 12231                           Latitude:   37° 58.6' N (  37.97670)
USGS Quad:  CRISFIELD                       Longitude:  75° 51.8' W ( -75.86330)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  NO 12 1969
                         DESIGNATION:          857 1091 TIDAL 12

MONUMENTATION:           Tidal Station disk                    VM#:         3042
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:  Sidewalk                              OPUS PID:        
LATITUDE:   37° 58.6' N (  37.97670)          LONGITUDE:  75° 51.9' W ( -75.86500)


The bench mark is a disk set flush in a concrete sidewalk 14 m (45 ft) NW from
the centerline of Main Street, and 0.3 m (1.0 ft) SE of the SE corner of the J.
P. Tawes & Brothers building on Main Street.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  5

                                                                                
Station ID: 8571091                         PUBLICATION DATE:  09/05/2013
Name:       CRISFIELD                                         
            MD
NOAA Chart: 12231                           Latitude:   37° 58.6' N (  37.97670)
USGS Quad:  CRISFIELD                       Longitude:  75° 51.8' W ( -75.86330)


                            T I D A L   D A T U M S 


Tidal datums at CRISFIELD based on:

     LENGTH OF SERIES:      7 MONTHS
     TIME PERIOD:           May 1977 - November 1977
     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   =  0.656
     MEAN HIGH WATER                            MHW    =  0.605
     North American Vertical Datum              NAVD88 =  0.353
     MEAN TIDE LEVEL                            MTL    =  0.321
     MEAN SEA LEVEL                             MSL    =  0.305
     MEAN LOW WATER                             MLW    =  0.037
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     NO 10 1942                                  0.938    0.333
     1091 A                                      1.159    0.554
     1091 B                                      1.600    0.995
     NO 12 1969                                  1.309    0.704


Foot Notes:

Bench mark "1091 A" is based on one differential leveling connection and do not
meet the quality control standards of the NOS. Therefore, caution should be used
when deriving elevations for these marks.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  5

                                                                                
Station ID: 8571091                         PUBLICATION DATE:  09/05/2013
Name:       CRISFIELD                                         
            MD
NOAA Chart: 12231                           Latitude:   37° 58.6' N (  37.97670)
USGS Quad:  CRISFIELD                       Longitude:  75° 51.8' W ( -75.86330)


                             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.

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