U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 7
PUBLICATION DATE: 10/15/1987
Station ID: 8594900 SUPERCEDED DATE: 04/21/2003
Name: WASHINGTON, D.C., WASHINGTON CHANNEL, POTOMAC RIVE
DISTRICT OF COLUMBIA
NOAA Chart: 12289 Latitude: 38° 52.5' N
USGS Quad: WASHINGTON WEST Longitude: 77° 1.4' W
To reach the tidal bench marks from where I-395 northbound splits, travel 0.7
mile (1.0 km) along I-395 northbound to the Maine Avenue S.W. exit, take the
Maine Avenue SW exit road for 0.2 mile (0.3 km) until it dead ends into Water
Street S.W., turn SE onto Water Street, S.W., and proceed 0.5 mile (0.8 km) to
the Washington Boat Lines facility at Pier 4. The tide station is located near
the south end of the pier in a 10-foot by 10-foot room located in the interior
of the maintenance area.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: TIDAL NO 1 1951
MONUMENTATION: Survey Disk VM#: 456
AGENCY: PID#: HV1980
SETTING CLASSIFICATION: Concrete Seawall
The bench mark is set in the concrete seawall at the southern inshore corner of
Pier 4, 50 feet (15 m) SW of the SW curb of Water Street, S.W., 14 feet (4 m) SE
of the centerline of the SE gate entrance to the pier, 11.7 feet (3.6 m) east of
the east corner of the Washington Boat Lines building, and 5.8 feet (1.8 m) SE
of the first brick fence pillar SE of the building.
BENCH MARK STAMPING: NO 4 1973
MONUMENTATION: Survey Disk VM#: 458
AGENCY: PID#: HV9068
SETTING CLASSIFICATION: Concrete Seawall
The bench mark is set in concrete seawall just north of Pier 4, 83.5 feet (25.5
m) NW of the centerline of the NW gate, 59 feet (18 m) south of the southern
corner of a concrete curb surrounding a paid parking area, and 11.9 feet (3.6 m)
NW of the northernmost brick fence pillar to the north of the pier.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 7
PUBLICATION DATE: 10/15/1987
Station ID: 8594900 SUPERCEDED DATE: 04/21/2003
Name: WASHINGTON, D.C., WASHINGTON CHANNEL, POTOMAC RIVE
DISTRICT OF COLUMBIA
NOAA Chart: 12289 Latitude: 38° 52.5' N
USGS Quad: WASHINGTON WEST Longitude: 77° 1.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 5 1973
MONUMENTATION: Survey Disk VM#: 459
AGENCY: PID#: HV9069
SETTING CLASSIFICATION: Concrete Seawall
The bench mark is set in the concrete seawall at the northern inshore corner of
Pier 4, 82 feet (25 m) SW of the first light pole NW of the Washington Boat
Lines driveway entrance, 11.9 feet (3.6 m) NW of the centerline of the NW gate
entrance, 9.5 feet (2.9 m) north of the NW corner of the Washington Boat Lines
building, and 1.3 feet (0.4 m) NW of the first brick fence pillar NW of the NW
gate.
BENCH MARK STAMPING: 1347
MONUMENTATION: Survey Disk VM#: 460
AGENCY: PID#: HV1985
SETTING CLASSIFICATION: Concrete Seawall
The bench mark is in the concrete seawall between Pier 4 and Pier 5, 113.2 feet
(34.5 m) SE of the centerline of the SE gate, 34.3 feet (10.5 m) south of the
first light pole SW of the Washington Boat Lines driveway entrance, 28.3 feet
(8.6 m) SW of the SW curb of the Water Street cul-de-sac curb, 13.3 feet (4.1 m)
NW of the last brick fence pillar SE of the SE gate, and 2 feet (1 m) NE of the
SW edge of the seawall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 7
PUBLICATION DATE: 10/15/1987
Station ID: 8594900 SUPERCEDED DATE: 04/21/2003
Name: WASHINGTON, D.C., WASHINGTON CHANNEL, POTOMAC RIVE
DISTRICT OF COLUMBIA
NOAA Chart: 12289 Latitude: 38° 52.5' N
USGS Quad: WASHINGTON WEST Longitude: 77° 1.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 859 4900 A 1977
MONUMENTATION: Survey Disk VM#: 461
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Ramp
The bench mark is in a concrete delivery ramp located at the NW corner of the
south half of the Arena Stage Theater building, 100 feet (30 m) east from the
start of the sidewalk leading to the ramp from the sidewalk along the NE side of
Maine Avenue, 13 feet (4 m) west of the double steel doors of the ramp, and 1
foot (0.3 m) north of the south wall of the ramp.
BENCH MARK STAMPING: 4900 B 1977
MONUMENTATION: Survey Disk VM#: 462
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Retaining Wall
The bench mark is set in a concrete retaining wall of a ventilation well located
on the north wall by the NE corner of the north half of the Arena Stage Theater
building, 42.1 feet (12.8 m) west of the west curb of 6th Street, 8.2 feet (2.5
m) south of the south curb of the north Arena Stage parking lot, and 3.8 feet
(1.2 m) north of the north wall.
BENCH MARK STAMPING: 4900 C 1977
MONUMENTATION: Survey Disk VM#: 463
AGENCY: PID:
SETTING CLASSIFICATION: Concrete Retaining Wall
The bench mark is set in the NW corner of a concrete retaining wall bordering
the entrance to an underground parking lot just SE of the Barley Mow/Casa Maria
Restaurant, 61 feet (19 m) NW of a bell in the park area to the SE of the
parking entrance, 34 feet (10 m) NE of the iron fence bordering the SW side of
the area, and 20 feet (6 m) NW of the SE corner of the retaining wall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 7
PUBLICATION DATE: 10/15/1987
Station ID: 8594900 SUPERCEDED DATE: 04/21/2003
Name: WASHINGTON, D.C., WASHINGTON CHANNEL, POTOMAC RIVE
DISTRICT OF COLUMBIA
NOAA Chart: 12289 Latitude: 38° 52.5' N
USGS Quad: WASHINGTON WEST Longitude: 77° 1.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4900 D 1982
MONUMENTATION: Survey Disk VM#: 464
AGENCY: PID:
SETTING CLASSIFICATION: Galvanized Steel Rod
The bench mark is along the SE side of the cul-de-sac at the SE end of Water
Street, S.W., 76.7 feet (23.4 m) SW of the SW edge of the sidewalk running NW-SE
through the park area, 26 feet (8 m) NE Of the NE edge of the driveway entrance
to Pier 5, 8.0 feet (2 m) SE of the SE curb of the cul-de-sac, and 1.0 foot (0.3
m) NW of the NW corner of the Pier 5 parking lot. The bench mark is set at
grade, crimped to a galvanized steel rod driven 8 feet (3 m) to refusal, and
encased in a 4-inch PVC pipe with cap.
BENCH MARK STAMPING: 4900 E 1982
MONUMENTATION: Survey Disk VM#: 465
AGENCY: PID:
SETTING CLASSIFICATION: Galvanized Steel Rod
The bench mark is set along the NE side of Water Street SW near its intersection
with M Place SW, 50 feet (15 m) west of the light pole at the NE corner of M
Place and Water Street, 12.5 feet (3.8 m) NW of the center of the manhole cover
just NW of the NE curb of Water Street. The bench mark is set at grade, crimped
to a galvanized steel rod driven 14 feet (4 m) to refusal, and encased in a
4-inch PVC pipe with cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 7
PUBLICATION DATE: 10/15/1987
Station ID: 8594900 SUPERCEDED DATE: 04/21/2003
Name: WASHINGTON, D.C., WASHINGTON CHANNEL, POTOMAC RIVE
DISTRICT OF COLUMBIA
NOAA Chart: 12289 Latitude: 38° 52.5' N
USGS Quad: WASHINGTON WEST Longitude: 77° 1.4' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 4900 F 1982
MONUMENTATION: Survey Disk VM#: 466
AGENCY: PID:
SETTING CLASSIFICATION: Galvanized Steel Rod
The bench mark is set along the NE side of Water Street SW near its intersection
with Connector Road SW, 68 feet (21 m) SW of the first light pole just north of
the Maine Avenue and Connector Road intersection, 42 feet (13 m) NW of the NW
curb of Connector Road, 16 feet (5 m) NW of the center of the manhole cover just
NW of the NW corner of Connector Road and WaterStreet, and 3 feet (1 m) NE of
the NE curb of Water Street. The bench mark is set at grade, crimped to a
galvanized steel rod driven 30 feet (9 m) to refusal, and encased in a 4-inch
PVC pipe with cap.
BENCH MARK STAMPING: NO STAMPING 1
MONUMENTATION: Survey Disk VM#: 467
AGENCY: PID#: HV1983
SETTING CLASSIFICATION: Concrete Pier Deck
The bench mark is set in the SE corner of Pier 4 at the Point of Tangency where
the curved section of bumper meets the southern edge of the pier, 14.5 feet (4.4
m) NE of a point of line with the SW end of the pier, and 0.8 foot (0.2 m) north
of the south edge of the pier.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 7
PUBLICATION DATE: 10/15/1987
Station ID: 8594900 SUPERCEDED DATE: 04/21/2003
Name: WASHINGTON, D.C., WASHINGTON CHANNEL, POTOMAC RIVE
DISTRICT OF COLUMBIA
NOAA Chart: 12289 Latitude: 38° 52.5' N
USGS Quad: WASHINGTON WEST Longitude: 77° 1.4' W
T I D A L D A T U M S
Tidal datums at WASHINGTON, D.C., WASHINGTON CHANNEL, POTOMAC RIVE based on:
LENGTH OF SERIES: 19 YEARS
TIME PERIOD: 1960-1978
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION:
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (10/17/1942) = 11.30
MEAN HIGHER HIGH WATER MHHW = 3.18
MEAN HIGH WATER MHW = 2.94
MEAN TIDE LEVEL MTL = 1.56
* NATIONAL GEODETIC VERTICAL DATUM NGVD29 = 0.85
MEAN LOW WATER MLW = 0.17
MEAN LOWER LOW WATER MLLW = 0.00
LOWEST OBSERVED WATER LEVEL (02/26/1967) = -4.80
* NGVD reference based on elevations published in Quad 380771, 1974, and NOS
leveling of 1985.
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
TIDAL NO 1 1951 9.19 6.25
NO 4 1973 9.61 6.67
NO 5 1973 9.21 6.27
1347 9.19 6.25
859 4900 A 1977 19.07 16.13
4900 B 1977 21.68 18.74
4900 C 1977 20.15 17.21
4900 D 1982 11.28 8.34
4900 E 1982 15.27 12.33
4900 F 1982 13.87 10.93
NO STAMPING 1 9.26 6.32
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 7 of 7
PUBLICATION DATE: 10/15/1987
Station ID: 8594900 SUPERCEDED DATE: 04/21/2003
Name: WASHINGTON, D.C., WASHINGTON CHANNEL, POTOMAC RIVE
DISTRICT OF COLUMBIA
NOAA Chart: 12289 Latitude: 38° 52.5' N
USGS Quad: WASHINGTON WEST Longitude: 77° 1.4' W
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 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.