U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
PUBLICATION DATE: 11/06/1991
Station ID: 8761927 SUPERCEDED DATE: 04/21/2003
Name: U.S.C.G. NEW CANAL STATION, LAKE PONTCHARTRAIN
LOUISIANA
NOAA Chart: 11369 Latitude: 30° 1.6' N
USGS Quad: SPANISH FORT Longitude: 90° 6.8' W
To reach the tidal bench marks from the intersection of Robert E. Lee and West
End Boulevards, near West End Park in Metarie, proceed north on West End
Boulevard for 0.4 mile (0.6 km), to the U.S. Coast Guard New Canal Station on
the left. The bench marks are in the vicinity of the station, Southern Yacht
Club, and east along Lakeshore Drive. The tide gage and staff are at the SW
corner of the Coast Guard dock on the canal.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 1927 A 1982
MONUMENTATION: Survey Disk VM#: 830
AGENCY: PID:
SETTING CLASSIFICATION: Stainless Steel Rod
The primary bench mark is along the lakefront east of the Coast Guard station,
225 feet (69 m) ENE of Bench Mark ALCO 1931 (Reference Mark), 96 feet (29 m) NE
of utility pole #17, 77 feet (23 m) NNW of the centerline of Lakeshore Drive, 54
feet (16 m) WSW of utility pole #502, and 14 feet (4 m) SSE of a concrete sea
wall. The bench mark is 0.3 foot (0.1 m) below ground level, crimped to a
stainless steel rod driven 68 feet (21 m) to substantial resistance, and encased
in a 4-inch PVC pipe and concrete kickblock.
BENCH MARK STAMPING: ALCO 1931 (REFERENCE MARK)
MONUMENTATION: Survey Disk VM#: 831
AGENCY: PID#: BJ1344
SETTING CLASSIFICATION: Concrete Sea Wall
The bench mark is set flush in the top of a sea wall, beneath a steel gate in a
fence along the top of the sea wall, near the Coast Guard Station, 87 feet (27
m) west of Bench Mark ALCO 1931 (Triangulation Station), and 23 feet (7 m) east
of the west end of the sea wall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
PUBLICATION DATE: 11/06/1991
Station ID: 8761927 SUPERCEDED DATE: 04/21/2003
Name: U.S.C.G. NEW CANAL STATION, LAKE PONTCHARTRAIN
LOUISIANA
NOAA Chart: 11369 Latitude: 30° 1.6' N
USGS Quad: SPANISH FORT Longitude: 90° 6.8' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: ALCO 1931 (TRIANGULATION STATION)
MONUMENTATION: Survey Disk VM#: 832
AGENCY: PID#: BJ1342
SETTING CLASSIFICATION: Concrete Sea Wall
The bench mark is set in the top of the sea wall near the Coast Guard Station,
115 feet (35 m) east of the west end of the sea wall, 112 feet (34 m) NW of the
centerline of Lakeshore Drive, and 70 feet (21 m) east of a steel fence corner
post on top of the sea wall.
BENCH MARK STAMPING: V 148 1951
MONUMENTATION: Survey Disk VM#: 833
AGENCY: PID#: BJ1343
SETTING CLASSIFICATION: Concrete Sea Wall
The bench mark is set in the top of a sea wall at Southern Yacht Club, directly
across the canal from the Coast Guard station, 67 feet (20 m) east of the SE
corner of the clubhouse, 34.5 feet (10.5 m) north of the south end of the sea
wall surrounding the yacht club, and 2 feet (1 m) above ground level.
BENCH MARK STAMPING: 1927 B 1982
MONUMENTATION: Survey Disk VM#: 834
AGENCY: PID:
SETTING CLASSIFICATION: Stainless Steel Rod
The bench mark is along the lakefront, 321 feet (98 m) ENE of Bench Mark 1927 A
1982, 101 feet (31 m) NE of utility pole #19, 68 feet (21 m) NNW of the
centerline of Lakeshore Drive, and 34 feet (10 m) WSW of utility pole #504, and
20 feet (6 m) SSE of a concrete sea wall. The bench mark is 0.3 foot (0.1 m)
below ground level, crimped to a stainless steel rod driven 72 feet (22 m) to
substantial resistance, and encased in a 4-inch PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
PUBLICATION DATE: 11/06/1991
Station ID: 8761927 SUPERCEDED DATE: 04/21/2003
Name: U.S.C.G. NEW CANAL STATION, LAKE PONTCHARTRAIN
LOUISIANA
NOAA Chart: 11369 Latitude: 30° 1.6' N
USGS Quad: SPANISH FORT Longitude: 90° 6.8' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: X 374 1985
MONUMENTATION: Survey Disk VM#: 836
AGENCY: PID#: BJ3686
SETTING CLASSIFICATION: Stainless Steel Rod
The bench mark is near the entrance to the Coast Guard station, 90.0 feet (27.4
m) north of the centerline of Lakeshore Drive, 90.0 feet (27.4 m) ESE of the
east gate post of a chainlink fence, 37.0 feet (11.3 m) ENE of lamp post #500,
31.5 feet (9.6 m) SSE of Bench Mark ALCO 1931 (Triangulation Station). The bench
mark is 1 foot (0.3 m) above the drive, crimped to a stainless steel rod driven
78 feet (24 m), and encased in a pipe level with the ground.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
PUBLICATION DATE: 11/06/1991
Station ID: 8761927 SUPERCEDED DATE: 04/21/2003
Name: U.S.C.G. NEW CANAL STATION, LAKE PONTCHARTRAIN
LOUISIANA
NOAA Chart: 11369 Latitude: 30° 1.6' N
USGS Quad: SPANISH FORT Longitude: 90° 6.8' W
T I D A L D A T U M S
Tidal datums at U.S.C.G. NEW CANAL STATION, LAKE PONTCHARTRAIN based on:
LENGTH OF SERIES: 87 MONTHS
TIME PERIOD: 1983-1990
TIDAL EPOCH: 1960-1978
CONTROL TIDE STATION: 8747437 BAY WAVELAND Y.C., MS
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET:
HIGHEST OBSERVED WATER LEVEL (01/20/1983) = 3.55
MEAN HIGHER HIGH WATER (MHHW) = 0.54
MEAN HIGH WATER (MHW) = 0.53
MEAN TIDE LEVEL (MTL) = 0.27
MEAN LOW WATER (MLW) = 0.00
MEAN LOWER LOW WATER (MLLW) = 0.00
LOWEST OBSERVED WATER LEVEL (12/25/1989) = -2.32
National Geodetic Vertical Datum (NGVD 29)
Bench Mark Elevation Information In FEET above:
Stamping or Designation MLLW MHW
1927 A 1982 5.48 4.95
ALCO 1931 (REFERENCE MARK) 6.03 5.50
ALCO 1931 (TRIANGULATION STATION) 6.31 5.78
V 148 1951 6.79 6.26
1927 B 1982 5.72 5.19
X 374 1985 5.34 4.81
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
PUBLICATION DATE: 11/06/1991
Station ID: 8761927 SUPERCEDED DATE: 04/21/2003
Name: U.S.C.G. NEW CANAL STATION, LAKE PONTCHARTRAIN
LOUISIANA
NOAA Chart: 11369 Latitude: 30° 1.6' N
USGS Quad: SPANISH FORT Longitude: 90° 6.8' 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 (NAVD 88).
NGVD 29 is a fixed datum adopted as a national standard geodetic reference for
heights but is now considered superseded. NGVD 29 is sometimes referred to as
Sea Level Datum of 1929 or as Mean Sea Level on some early issues of Geological
Survey Topographic Quads. NGVD 29 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 NGVD 29 are available from the National
Geodetic Survey (NGS) data base via the World Wide Web at
National Geodetic Survey.
NAVD 88 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. NAVD 88 replaces NGVD 29 as the national
standard geodetic reference for heights. Bench mark elevations relative to
NAVD 88 are available from NGS through the World Wide Web at
National Geodetic Survey.
NGVD 29 and NAVD 88 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 NAVD 88 elevation is shown on the Elevations of Tidal Datums Table Referred
to MLLW only when two or more of the bench marks listed have NAVD 88 elevations.
The NAVD 88 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, NAVD 88 bench mark elevations computed indirectly from the tidal
datums elevation table may differ slightly from NAVD 88 elevations listed for
each bench mark in the NGS database.