U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 7
Station ID: 8570691 PUBLICATION DATE: 09/28/2015
Name: BUNTING'S BRIDGE, CHINCOTEAGUE BAY, MD
MD
NOAA Chart: 12211 Latitude: 38° 8.3' N ( 38.13894)
USGS Quad: TINGLES ISLAND Longitude: 75° 11.0' W ( -75.18353)
To reach the bench mark from the National Park Service Maryland District
Visitors Center in a vehicle that can drive on sand beach, turn right onto Route
611 Verrazano Bridge road and continue southeast 1.1 mi (1.8 km) over the Bridge
onto Assateague Island, turn at first right on the Island and continue south for
3.5 mi (5.6 km) on Stephen Decatur Memorial road which becomes Bayberry Drive to
the rotary, take the second exit to the right, continue on Bayberry drive for
0.2 mi (0.3 km) to the air station, continue through the gate and travel south
on a sand trail and then beach for 3.61 mi (5.8 km) to the 21 km (13.1 mi)
marker sign post, turn right off of beach through NPS locked gate and continue
on sand trail through brush and trees westerly for 0.34 mi (0.5 km) staying left
at fork to Buntings Bridge and the tide station on the left. The bench marks
are located along the trail on both sides of the bridge.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 0691 D 2012
DESIGNATION: 857 0691 D
MONUMENTATION: Flange-encased Rod VM#: 20657
AGENCY: National Parks Services IDB PID#:
SETTING CLASSIFICATION: stainless steel rod OPUS PID#: BBDL81
LATITUDE: 38° 8.3' N ( 38.13839) LONGITUDE: 75° 10.8' W ( -75.18031)
The primary bench mark is a flange-encased rod set in a sandy clearing on the
south side of Buntings Bridge Trail, 64.50 m (211.6 ft) SSW of bench mark 857
0691 E, 22.04 m (72.3 ft) south of the centerline of the trail, 10.40 m (34.1
ft) south of the edge of the clearing, 7.75 m (25.4 ft) NNE of the edge of the
clearing, 6.20 m (20.3 ft) NW of the edge of the clearing, and 1.37 m (4.5 ft)
NNE of a carsonite witness post. The datum point is set flush with the ground,
being the top of a stainless steel rod driven 24.4 m (80.0 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)
aluminum logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
Station ID: 8570691 PUBLICATION DATE: 09/28/2015
Name: BUNTING'S BRIDGE, CHINCOTEAGUE BAY, MD
MD
NOAA Chart: 12211 Latitude: 38° 8.3' N ( 38.13894)
USGS Quad: TINGLES ISLAND Longitude: 75° 11.0' W ( -75.18353)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0691 E 2012
DESIGNATION: 857 0691 E
MONUMENTATION: Flange-encased Rod VM#: 20658
AGENCY: National Parks Services IDB PID#:
SETTING CLASSIFICATION: stainless steel rod OPUS PID#: BBDL14
LATITUDE: 38° 8.3' N ( 38.13889) LONGITUDE: 75° 10.8' W ( -75.18003)
The bench mark is a flange-encased rod set in a sandy clearing on the north side
of Buntings Bridge trail, 64.50 m (211.6 ft) NNE of bench mark 857 0691 D, 41.60
m (136.5 ft) NNE of the centerline of the trail, 8.95 m (29.4 ft) ESE of the
edge of the clearing, 5.50 m (18.0 ft) WNW of the edge of the clearing, 3.95 m
(13.0 ft) NNE of the edge of the clearing, and 1.26 m (4.1 ft) south of a
carsonite witness post. The datum point is set flush with the ground, being the
top of a stainless steel rod driven 15.8 m (51.8 ft) in a sleeve extending to a
depth of 0.9 m (3.0 ft) and encased in a 5 inch (13 cm) aluminum logo cap
projecting 0.12 m (0.4 ft) above grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
Station ID: 8570691 PUBLICATION DATE: 09/28/2015
Name: BUNTING'S BRIDGE, CHINCOTEAGUE BAY, MD
MD
NOAA Chart: 12211 Latitude: 38° 8.3' N ( 38.13894)
USGS Quad: TINGLES ISLAND Longitude: 75° 11.0' W ( -75.18353)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0691 A 2012
DESIGNATION: 857 0691 A
MONUMENTATION: Flange-encased Rod VM#: 20659
AGENCY: National Parks Services IDB PID#:
SETTING CLASSIFICATION: stainless steel rod OPUS PID:
LATITUDE: 38° 8.4' N ( 38.14064) LONGITUDE: 75° 11.2' W ( -75.18661)
The bench mark is a flange-encased rod set on a sandy rise in the clearing on
the south side of the trail, 43.65 m (143.2 ft) NW of the centerline of the
trail where it passes into trees, 25.10 m (82.3 ft) WSW of the ridge running
along the north side of trail in trees, 9.14 m (30.0 ft) WSW of the centerline
of the trail to the boat launch, 8.37 m (27.5 ft) east of the tree line, and
1.09 ENE of carsonite witness post. The datum point is set 6 cm (2 inches)
below ground, being the top of a stainless steel rod driven 24.2 m (79.4 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) aluminum logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
Station ID: 8570691 PUBLICATION DATE: 09/28/2015
Name: BUNTING'S BRIDGE, CHINCOTEAGUE BAY, MD
MD
NOAA Chart: 12211 Latitude: 38° 8.3' N ( 38.13894)
USGS Quad: TINGLES ISLAND Longitude: 75° 11.0' W ( -75.18353)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0691 B 2012
DESIGNATION: 857 0691 B
MONUMENTATION: Flange-encased Rod VM#: 20660
AGENCY: National Parks Services IDB PID#:
SETTING CLASSIFICATION: stainless steel rod OPUS PID:
LATITUDE: 38° 8.3' N ( 38.13861) LONGITUDE: 75° 11.0' W ( -75.18381)
The bench mark is a flange-encased rod set in a grassy clearing SE of the trail
on the SW side of Buntings Bridge, 37.15 m (121.9 ft) south of the centerline of
trail at the bottom of the bridge ramp, 13.50 m (44.3 ft) SSE of the centerline
of the trail, 6.9 m (22.6 ft) north of tree line, and 1.10 m (3.6 ft) NW of
carsonite witness post. The datum point is set 4 cm (2 inches) below ground,
being the top of a stainless steel rod driven 15.8 m (51.8 ft) in a sleeve
extending to a depth of 0.9 m (3.0 ft) and encased in a 5 inch (13 cm) aluminum
logo cap projecting 3.5 cm (1 inch) above grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
Station ID: 8570691 PUBLICATION DATE: 09/28/2015
Name: BUNTING'S BRIDGE, CHINCOTEAGUE BAY, MD
MD
NOAA Chart: 12211 Latitude: 38° 8.3' N ( 38.13894)
USGS Quad: TINGLES ISLAND Longitude: 75° 11.0' W ( -75.18353)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0691 C 2012
DESIGNATION: 857 0691 C
MONUMENTATION: Flange-encased Rod VM#: 20661
AGENCY: National Parks Services IDB PID#:
SETTING CLASSIFICATION: stainless steel rod OPUS PID:
LATITUDE: 38° 8.3' N ( 38.13897) LONGITUDE: 75° 10.9' W ( -75.18158)
The bench mark is a flange-encased rod set in a small grassy clearing on the
south side of Buntings Bridge trail, 19.45 m (63.8 ft) south of center of gravel
storage area on north side of trail, 17.64 m (57.9 ft) northeast of edge of
slough, 12.20 m (40.0 ft) south of the centerline of the trail, 7.5 m (24.6 ft)
south of southern brush line alongside of road, and 1.10 m (3.6 ft) NNEt of
carsonite witness post. The datum point is set 4 cm (2 inches) below ground,
being the top of a stainless steel rod driven 15.8 m (51.8 ft) in a sleeve
extending to a depth of 0.9 m (3.0 ft) and encased in a 5 inch (13 cm) aluminum
logo cap projecting 10 cm (4 inches) above grade.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
Station ID: 8570691 PUBLICATION DATE: 09/28/2015
Name: BUNTING'S BRIDGE, CHINCOTEAGUE BAY, MD
MD
NOAA Chart: 12211 Latitude: 38° 8.3' N ( 38.13894)
USGS Quad: TINGLES ISLAND Longitude: 75° 11.0' W ( -75.18353)
T I D A L D A T U M S
Tidal datums at BUNTING'S BRIDGE, CHINCOTEAGUE BAY, MD based on:
LENGTH OF SERIES: 1 YEAR
TIME PERIOD: March 2013 - February 2014
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8570283 OCEAN CITY INLET
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (03/10/2013) = 0.790
MEAN HIGHER HIGH WATER MHHW = 0.251
North American Vertical Datum NAVD88 = 0.248
MEAN HIGH WATER MHW = 0.219
MEAN SEA LEVEL MSL = 0.126
MEAN TIDE LEVEL MTL = 0.126
MEAN LOW WATER MLW = 0.033
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (04/22/2013) = -0.374
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
0691 D 2012 1.148 0.929
0691 E 2012 1.703 1.484
0691 A 2012 2.675 2.456
0691 B 2012 0.520 0.301
0691 C 2012 0.560 0.341
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
Station ID: 8570691 PUBLICATION DATE: 09/28/2015
Name: BUNTING'S BRIDGE, CHINCOTEAGUE BAY, MD
MD
NOAA Chart: 12211 Latitude: 38° 8.3' N ( 38.13894)
USGS Quad: TINGLES ISLAND Longitude: 75° 11.0' W ( -75.18353)
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.