U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8572669 PUBLICATION DATE: 04/22/2013
Name: HILLSBORO, TUCKAHOE CREEK
MD
NOAA Chart: 12268 Latitude: 38° 55.0' N ( 38.91670)
USGS Quad: RIDGELY Longitude: 75° 56.7' W ( -75.94500)
From the intersection of 404 and 303 proceed south on 303 to ALT 404, proceed
east on ALT 404 approximately 2.4 km (1.5 mi) over the bridge and into Caroline
County. The Hillsboro boat ramp is on the right, the gauge was located on the
seawall.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 2669 A 2005
DESIGNATION: 857 2669 A
MONUMENTATION: Flange-encased Rod VM#: 17858
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Stainless steel rod in sleeve OPUS PID:
LATITUDE: 38° 55.0' N ( 38.91670) LONGITUDE: 75° 56.7' W ( -75.94500)
The primary bench mark is a flange-encased rod located in the county park north
east of the boat ramp, 17.98 m (59.0 ft) SE of the center of a large drain
culvert, 10.36 m (34.0 ft) NW of the entrance driveway into the park, 2.3 m (7.5
ft) SSW from the witness post, and 1.81 m (5.9 ft) SSW of phone pole
37154-13321. The datum point is set flush with the ground, being the top of a
stainless steel rod driven 8.0 m (26.2 ft) to refusal, with a sleeve extending
0.9 m (3.0 ft) and encased in a 5-inch PVC pipe with a 5-inch NOS logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8572669 PUBLICATION DATE: 04/22/2013
Name: HILLSBORO, TUCKAHOE CREEK
MD
NOAA Chart: 12268 Latitude: 38° 55.0' N ( 38.91670)
USGS Quad: RIDGELY Longitude: 75° 56.7' W ( -75.94500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2669 B 2005
DESIGNATION: 857 2669 B
MONUMENTATION: Tidal Station disk VM#: 17859
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Loading platform OPUS PID:
LATITUDE: 38° 55.0' N ( 38.91670) LONGITUDE: 75° 56.9' W ( -75.94830)
The bench mark is a disk located on the Maryland truck loading platform in the
southern corner, 36.48 m (119.7 ft) SSE of a power pole with transformers and
labeled "37064 13331", 10.30 m (33.8 ft) WSW of power pole "225", 0.35 m (1.2
ft) NNE of the loading dock wall.
BENCH MARK STAMPING: 2669 C 2005
DESIGNATION: 857 2669 C
MONUMENTATION: Tidal Station disk VM#: 17860
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Concrete abutment OPUS PID:
LATITUDE: 38° 55.0' N ( 38.91670) LONGITUDE: 75° 56.7' W ( -75.94500)
The bench mark is a disk located on the eastern abutment of the bridge over the
Tuckahoe Creek, 46.94 m (154.0 ft) west of the SW corner of a stone block
garage located at 21908 Main Street, and 10.00 m (32.8 ft) north of power pole
"220", and 0.49 m (1.6 ft) above pavement level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8572669 PUBLICATION DATE: 04/22/2013
Name: HILLSBORO, TUCKAHOE CREEK
MD
NOAA Chart: 12268 Latitude: 38° 55.0' N ( 38.91670)
USGS Quad: RIDGELY Longitude: 75° 56.7' W ( -75.94500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 2669 D 2005
DESIGNATION: 857 2669 D
MONUMENTATION: Tidal Station disk VM#: 17861
AGENCY: National Ocean Service (NOS) IDB PID#:
SETTING CLASSIFICATION: Town Hall OPUS PID:
LATITUDE: 38° 54.9' N ( 38.91500) LONGITUDE: 75° 56.7' W ( -75.94500)
The bench mark is located on the back side of the Hillsboro Town Hall, 20.30 m
(66.6 ft) NW of light pole "126," 12.31 m (40.4 ft) ESE of the west corner of
town hall, and 4.21 m (13.8 ft) WNW from the south corner of town hall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8572669 PUBLICATION DATE: 04/22/2013
Name: HILLSBORO, TUCKAHOE CREEK
MD
NOAA Chart: 12268 Latitude: 38° 55.0' N ( 38.91670)
USGS Quad: RIDGELY Longitude: 75° 56.7' W ( -75.94500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 47
ALIAS: UNSTAMPED
MONUMENTATION: Tidal Station disk VM#: 17863
AGENCY: Unknown IDB PID#: HU0812
SETTING CLASSIFICATION: Brick foundation OPUS PID:
LATITUDE: 38° 55.0' N ( 38.91670) LONGITUDE: 75° 56.6' W ( -75.94330)
The bench mark is a disk set vertically in the NE corner of the original brick
foundation located east of the post office along State Highway ALT 404, at the
Frank Flemming House, and 1.2 m (3.9 ft) above the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8572669 PUBLICATION DATE: 04/22/2013
Name: HILLSBORO, TUCKAHOE CREEK
MD
NOAA Chart: 12268 Latitude: 38° 55.0' N ( 38.91670)
USGS Quad: RIDGELY Longitude: 75° 56.7' W ( -75.94500)
T I D A L D A T U M S
Tidal datums at HILLSBORO, TUCKAHOE CREEK based on:
LENGTH OF SERIES: 4 MONTHS
TIME PERIOD: May 2005 - August 2005
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8571892 CAMBRIDGE, CHOPTANK RIVER
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.807
MEAN HIGH WATER MHW = 0.755
MEAN SEA LEVEL MSL = 0.447
MEAN TIDE LEVEL MTL = 0.406
MEAN LOW WATER MLW = 0.057
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
2669 A 2005 2.287 1.532
2669 B 2005 3.074 2.319
2669 C 2005 3.499 2.744
2669 D 2005 13.864 13.109
47 14.344 13.589
Foot Notes:
Bench marks 2669 D 2005 and 47 are based on one differntial 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 6 of 6
Station ID: 8572669 PUBLICATION DATE: 04/22/2013
Name: HILLSBORO, TUCKAHOE CREEK
MD
NOAA Chart: 12268 Latitude: 38° 55.0' N ( 38.91670)
USGS Quad: RIDGELY Longitude: 75° 56.7' W ( -75.94500)
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.