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Datums Page Page 1 of 7
Station ID: 8653951 PUBLICATION DATE: 12/04/2012
Name: PETER'S DITCH
NC
NOAA Chart: 11555 Latitude: 35° 21.0' N ( 35.35014)
USGS Quad: BUXTON Longitude: 75° 30.7' W ( -75.51203)
To reach the tidal bench marks from the US Post Office in Avon, NC, proceed
north on North Carolina 12 for 0.9 KM (0.6 MI) to the intersection with Harbor
Road, turn left onto Harbor Road and proceed 1.0 KM (0.6 MI) west to a small
harbor on the right. The bench marks are around the harbor and near the
intersection of North Carolina 12 and Harbor Road. The tide gauge is located on
the Avon Seafood dock on the east side of the harbor.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 865 3951 B
DESIGNATION: 865 3951 B
MONUMENTATION: Metal Rod VM#: 20426
AGENCY: NOS IDB PID#:
SETTING CLASSIFICATION: Flange-encased rod OPUS PID:
LATITUDE: 35° 21.0' N ( 35.35025) LONGITUDE: 75° 30.7' W ( -75.51194)
The primary bench mark is a flange encased rod set on the east side of the
harbor in a grass parking area south of a concrete boat ramp, 19.12 m (62.7 ft)
west of the centerline of Harbor Road, 14.01 m (46.0 ft) north-northwest of the
northeast corner of the Avon Seafood building, 12.89 m (42.3 ft) north of the
northwest corner of the Avon Seafood building, 9.89 m (32.4 ft) west of the end
of the seawall at the east end of the boat ramp, 4.25 m (13.9 ft) south of the
centerline of the boat ramp, 2.34 m (7.7 ft) southeast of an orange carsonite
National Ocean Service witness post, 2.30 m (7.5 ft) east of the seaward edge of
the seawall and 1.97 m (6.5 ft) south of the seawall along the south side of the
boat ramp.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 8653951 PUBLICATION DATE: 12/04/2012
Name: PETER'S DITCH
NC
NOAA Chart: 11555 Latitude: 35° 21.0' N ( 35.35014)
USGS Quad: BUXTON Longitude: 75° 30.7' W ( -75.51203)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 865 3951 A
DESIGNATION: 865 3951 A
MONUMENTATION: Metal Rod VM#: 20427
AGENCY: NOS IDB PID#:
SETTING CLASSIFICATION: Flange-encased rod OPUS PID:
LATITUDE: 35° 21.0' N ( 35.34981) LONGITUDE: 75° 30.8' W ( -75.51261)
The bench mark is a flange encased rod set near the southwest corner of the
harbor, 35.54 m (116.6 ft) north of the northeast corner of a house, 35.21 m
(115.5 ft) north-northeast of the northwest corner of the same house, 27.37 m
(89.8 ft) south-southwest of the northeast corner of the seawall on the south
side of the channel, 10.34 m (33.9 ft) northwest of a power pole with light and
meter, 9.76 m (32.0 ft) northwest of the southwest corner of the harbor, 7.74 m
(25.4 ft) west of the seawall and 3.33 m (10.9 ft) west-southwest of the south
most of two evergreen trees. The datum point is set 9 cm (4 inches) below grade
being the top of a stainless steel rod driven to substantial resistance, in a
sleeve extending to a depth of 0.9 m (3.0 ft) and encased in a 5-inch (13 cm)
National Ocean Service logo
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
Station ID: 8653951 PUBLICATION DATE: 12/04/2012
Name: PETER'S DITCH
NC
NOAA Chart: 11555 Latitude: 35° 21.0' N ( 35.35014)
USGS Quad: BUXTON Longitude: 75° 30.7' W ( -75.51203)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 865 3951 C
DESIGNATION: 865 3951 C
MONUMENTATION: Metal Rod VM#: 20428
AGENCY: NOS IDB PID#:
SETTING CLASSIFICATION: Flange-encased rod OPUS PID:
LATITUDE: 35° 21.0' N ( 35.35006) LONGITUDE: 75° 30.7' W ( -75.51125)
The bench mark is a flange encased rod set in an empty lot north of a three
story building, 56.49 m (185.3 ft) southeast of a concrete boat ramp leading to
the harbor on the west side of Harbor Road, 31.25 m (102.5 ft) east of a power
pole with a transformer and light, 24.73 m (81.1 ft) north-northeast of the
southeast corner of the three story building, 10.35 m (34.0 ft) northeast of the
northeast corner of the three story building and 0.82 m (2.7 ft) north of an
orange carsonite National Ocean Service witness post. The datum point is set 9
cm (4 inches) below ground being the top of a stainless steel rod driven 26.8 m
(87.9 ft) to refusal, in a sleeve extending to a depth of 0.9 m (3.0 ft) and
encased in a 5-inch (13 cm) National Ocean Service
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 8653951 PUBLICATION DATE: 12/04/2012
Name: PETER'S DITCH
NC
NOAA Chart: 11555 Latitude: 35° 21.0' N ( 35.35014)
USGS Quad: BUXTON Longitude: 75° 30.7' W ( -75.51203)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 865 3951 D
DESIGNATION: 865 3951 D
MONUMENTATION: Metal Rod VM#: 20429
AGENCY: NOS IDB PID#:
SETTING CLASSIFICATION: Flange-encased rod OPUS PID#: BBCS80
LATITUDE: 35° 21.0' N ( 35.35083) LONGITUDE: 75° 30.7' W ( -75.51214)
The bench mark is a flange encased rod set in the grass north of the harbor,
25.25 m (82.8 ft) west of the centerline of harbor road, 21.83 m (71.6 ft) south
of the centerline of O'Neal Road which is gravel, 8.79 m (28.8 ft) east of a 90
degree corner in the seawall, 3.68 m (12.1 ft) west-northwest of a 45 degree
bend in the seawall and 1.30 m (4.3 ft) north of the seawall and an orange
carsonite National Ocean Service witness post. The datum point is set 11 cm (4
inches) below the ground being the top of a stainless steel rod driven 28.0 m
(91.9 ft) to refusal and encased in a 5-inch (13 cm)
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 8653951 PUBLICATION DATE: 12/04/2012
Name: PETER'S DITCH
NC
NOAA Chart: 11555 Latitude: 35° 21.0' N ( 35.35014)
USGS Quad: BUXTON Longitude: 75° 30.7' W ( -75.51203)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: MAIL 1985
DESIGNATION: MAIL 1985
MONUMENTATION: Survey disk VM#: 20430
AGENCY: North Carolina Geodetic Survey IDB PID#:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 35° 21.2' N ( 35.35346) LONGITUDE: 75° 30.2' W ( -75.50326)
The bench mark is a survey disk set level with the highway in the yard of a
Subway, 25.9 m (85.0 ft) southeast of a metal flagpole, 19.5 m (64.0 ft)
southeast of the northeast corner of a concrete parking lot, 18.8 m (61.7 ft)
east-southeast of the southeast corner of the post office, 17.2 m (56.4 ft)
north-northeast of an Amoco sign, 12.3 m (40.4 ft) west-northwest of the
centerline of NC 12, 4.6 m (15.1 ft) east-northeast of a concrete property
marker and 3.8 m (12.5 ft) east-northeast of a telephone pedestal (12NP212W).
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
Station ID: 8653951 PUBLICATION DATE: 12/04/2012
Name: PETER'S DITCH
NC
NOAA Chart: 11555 Latitude: 35° 21.0' N ( 35.35014)
USGS Quad: BUXTON Longitude: 75° 30.7' W ( -75.51203)
T I D A L D A T U M S
Tidal datums at PETER'S DITCH based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: May 2012 - July 2012
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8654467 USCG STATION HATTERAS, PAMLICO SOUND
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.185
MEAN HIGH WATER MHW = 0.157
MEAN TIDE LEVEL MTL = 0.091
MEAN SEA LEVEL MSL = 0.090
MEAN LOW WATER MLW = 0.025
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
865 3951 B 1.091 0.934
865 3951 A 1.498 1.341
865 3951 C 1.076 0.919
865 3951 D 0.773 0.616
MAIL 1985 1.302 1.145
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
Station ID: 8653951 PUBLICATION DATE: 12/04/2012
Name: PETER'S DITCH
NC
NOAA Chart: 11555 Latitude: 35° 21.0' N ( 35.35014)
USGS Quad: BUXTON Longitude: 75° 30.7' W ( -75.51203)
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.