U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8570649 PUBLICATION DATE: 05/23/2003
Name: PUBLIC LANDING
MD
NOAA Chart: 12211 Latitude: 38° 8.9' N ( 38.14830)
USGS Quad: PUBLIC LANDING Longitude: 75° 17.1' W ( -75.28500)
To reach the tidal bench marks from the intersection of U.S. Highway 113 and
State Highway 365 in Snowhill, proceed east on State Highway 365 for 8.5 km (5.3
mi) to the public landing. The bench marks are near the county pier. The tide
gage and staff were on the east end and south side of the pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 0649 A 1985
DESIGNATION: 857 0649 A
MONUMENTATION: Tidal Station disk VM#: 3034
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete step OPUS PID:
LATITUDE: 38° 8.9' N ( 38.14830) LONGITUDE: 75° 17.1' W ( -75.28500)
The primary bench mark is a disk set flush in the bottom concrete step on the
south side of the Driscoll residence, 11.37 m (37.3 ft) SE of the extended
centerline of Bayside Road, 8.32 m (27.3 ft) NW of a 0.61 m (2.0 ft) diameter
cedar tree, and 7.71 m (25.3 ft) NE of the centerline of Route 365.
BENCH MARK STAMPING: 18 WDK 1963 RESET 1976
DESIGNATION: 857 0649 18 WDK RES 1976
MONUMENTATION: Triangulation Station disk VM#: 3033
AGENCY: US Geological Survey (USGS) IDB PID#:
SETTING CLASSIFICATION: Base of abandoned pole OPUS PID:
LATITUDE: 38° 8.9' N ( 38.14830) LONGITUDE: 75° 17.1' W ( -75.28500)
The bench mark is a disk set flush in the 1 m (2 ft) square concrete base of an
abandoned pole, 47 m (153 ft) NW of the centerline of Bayside Road, 6.61 m (21.7
ft) SW of the centerline of Route 365, and 1.22 m (4.0 ft) east of power pole
#163.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8570649 PUBLICATION DATE: 05/23/2003
Name: PUBLIC LANDING
MD
NOAA Chart: 12211 Latitude: 38° 8.9' N ( 38.14830)
USGS Quad: PUBLIC LANDING Longitude: 75° 17.1' W ( -75.28500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0649 B 1985
DESIGNATION: 857 0649 B
MONUMENTATION: Tidal Station disk VM#: 3035
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete pedestal OPUS PID:
LATITUDE: 38° 8.9' N ( 38.14830) LONGITUDE: 75° 17.1' W ( -75.28500)
The bench mark is a disk set flush in the top of a concrete pedestal of an
abandoned fuel storage tank, 13 m (43 ft) NW of the centerline of Bayside Road,
8 m (26 ft) SW of the centerline of State Highway 365, and 5 m (18 ft) NE of the
SE corner of a 2-story frame dwelling.
BENCH MARK STAMPING: 0649 C 1985
DESIGNATION: 857 0649 C
MONUMENTATION: Tidal Station disk VM#: 3036
AGENCY: Natioanl Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: DH7884
LATITUDE: 38° 8.9' N ( 38.14830) LONGITUDE: 75° 17.1' W ( -75.28500)
The bench mark is a disk located 27.74 m (91.0 ft) NW of the centerline of a
paved road, 11.89 m (39.0 ft) NE of the centerline of State Highway 365, and
0.70 m (2.3 ft) SW of power pole #120 with witness post. The bench mark is set
15 cm (0.5 ft) below the ground, crimped to the top of a stainless steel rod
driven an unspecified depth, and encased in a 5-inch PVC pipe and concrete
kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8570649 PUBLICATION DATE: 05/23/2003
Name: PUBLIC LANDING
MD
NOAA Chart: 12211 Latitude: 38° 8.9' N ( 38.14830)
USGS Quad: PUBLIC LANDING Longitude: 75° 17.1' W ( -75.28500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 0649 D 1985
DESIGNATION: 857 0649 D
MONUMENTATION: Tidal Station disk VM#: 3037
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 38° 8.9' N ( 38.14830) LONGITUDE: 75° 17.1' W ( -75.28500)
The bench mark is a disk located 52.27 m (171.5 ft) NW of power pole #118, 47.15
m (154.7 ft) SE of power pole #117, 31.70 m (104.0 ft) north of the north corner
of a 2-story frame dwelling (Hamaker's residence), and 10.52 m (34.5 ft) NE of
the centerline of Route 365. The bench mark is set 15 cm (0.5 ft) below the
surface, crimped to the top of a stainless steel rod driven 9.8 m (32 ft), and
encased in a 5-inch PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8570649 PUBLICATION DATE: 05/23/2003
Name: PUBLIC LANDING
MD
NOAA Chart: 12211 Latitude: 38° 8.9' N ( 38.14830)
USGS Quad: PUBLIC LANDING Longitude: 75° 17.1' W ( -75.28500)
T I D A L D A T U M S
Tidal datums at PUBLIC LANDING based on:
LENGTH OF SERIES: 3 MONTHS
TIME PERIOD: August 1985 - October 1985
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8558690 INDIAN RIVER INLET
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.216
MEAN HIGH WATER MHW = 0.192
MEAN SEA LEVEL MSL = 0.115
MEAN TIDE LEVEL MTL = 0.111
MEAN LOW WATER MLW = 0.031
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
0649 A 1985 3.158 2.966
18 WDK 1963 RESET 1976 2.952 2.760
0649 B 1985 2.886 2.694
0649 C 1985 3.513 3.321
0649 D 1985 4.007 3.815
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8570649 PUBLICATION DATE: 05/23/2003
Name: PUBLIC LANDING
MD
NOAA Chart: 12211 Latitude: 38° 8.9' N ( 38.14830)
USGS Quad: PUBLIC LANDING Longitude: 75° 17.1' W ( -75.28500)
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.