U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8766072 PUBLICATION DATE: 04/28/2020
Name: FRESHWATER CANAL LOCKS
LA
NOAA Chart: 11354 Latitude: 29° 33.1' N ( 29.55169)
USGS Quad: POINT AU FER Longitude: 92° 18.3' W ( -92.30519)
To reach Freshwater Canal Locks from exit 87 (LA-35) on I-10 west, proceed south
on LA-35 for 15.1 km (9.4 mi), then turn left and continue west on LA-35 for 0.8
km (0.5 mi), turn left and stay south on LA-35 for 33.8 km (21.0 mi) to LA-82,
continue straight on LA-82 for 24.6 km (15.3 mi) to the dirt road LA-3147. Make
a slight left and continue south on LA-3147 for 2.9 km (1.8 mi), then turn left
at the yield sign and continue on LA-3147 for 15.6 km (9.7 mi) to the entrance
of Army Corps of Engineers Freshwater Bayou Locks. The gauge is located south
of the locks on a cement section of the pier. The bench marks are located
throughout the property and in the park adjacent to the property.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 6072 A 2005
DESIGNATION: 876 6072 A
MONUMENTATION: Tidal Station disk VM#: 17966
AGENCY: National Ocean Service (NOS) IDB PID#: DJ9334
SETTING CLASSIFICATION: Cement structure OPUS PID#: DJ9334
LATITUDE: 29° 33.1' N ( 29.55178) LONGITUDE: 92° 18.3' W ( -92.30525)
The primary bench mark is a disk set flush in the cement structure located south
of the locks, 4.42 m (14.28 ft) east of the western edge of the cement
structure, 3.46 m (11.35 ft) SE of a wind vane, and 1.10 m (3.61 ft) west of a
man hole cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8766072 PUBLICATION DATE: 04/28/2020
Name: FRESHWATER CANAL LOCKS
LA
NOAA Chart: 11354 Latitude: 29° 33.1' N ( 29.55169)
USGS Quad: POINT AU FER Longitude: 92° 18.3' W ( -92.30519)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING:
DESIGNATION: 24 R
ALIAS: NO STAMPING
MONUMENTATION: Bolt VM#: 17969
AGENCY: US Army Corps of Engineers (COE) IDB PID:
SETTING CLASSIFICATION: Locks structure OPUS PID#: BBFX80
LATITUDE: 29° 33.2' N ( 29.55278) LONGITUDE: 92° 18.3' W ( -92.30544)
The bench mark is a brass bolt located in the most westernmost section of a
support wall in the southern locks, 0.89 m (2.9 ft) west of the cement/gravel
boundary of a road leading to the locks, 0.48 m (1.6 ft) south of a fence along
the road leading to the locks, and 0.30 m (1.0 ft) east of the most western edge
of the support wall.
BENCH MARK STAMPING: 6072 D 2009
DESIGNATION: 876 6072 D
MONUMENTATION: Flange-encased Rod VM#: 19603
AGENCY: National Ocean Survey/Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod without sleeve OPUS PID#: BBFX81
LATITUDE: 29° 33.3' N ( 29.55436) LONGITUDE: 92° 18.3' W ( -92.30567)
The bench mark is a flange-encased rod located 60.25 m (197.7 ft) of the corner
of the USACE main office, 20.95 m (68.7 ft) NW of the SW corner of the USACE
machine shop, 16.29 m (53.4 ft) WSW of the NW corner of the USACE machine shop,
3.14 m (10.3 ft) SSW of the SW corner of a concrete pad for a septic water pump,
and 1.44 m (4.7 ft) east of the fenceline on the westside of the USACE property.
The datum point is set 5 cm below grade, being the top of a stainless steel rod
driven 17.1 m (56.1 ft) to substantial resistance, in a sleeve extending to a
depth of 0.92 m, and encased in a 5-inch PVC pipe with NGS logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8766072 PUBLICATION DATE: 04/28/2020
Name: FRESHWATER CANAL LOCKS
LA
NOAA Chart: 11354 Latitude: 29° 33.1' N ( 29.55169)
USGS Quad: POINT AU FER Longitude: 92° 18.3' W ( -92.30519)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6072 E 2015
DESIGNATION: 876 6072 E
MONUMENTATION: Flange-encased Rod VM#: 21497
AGENCY: National Ocean Service (NOS) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 29° 33.2' N ( 29.55351) LONGITUDE: 92° 18.3' W ( -92.30555)
The bench mark is a flange encased rod located 34.65 m (113.7 ft) SW of a metal
fire hose enclosure labeled "Fire Station 2" on the eastern side of the
driveway, 22.97 m (75.4 ft) SE of the south corner of the Army Corps of
Engineers main building, 21.67 m (71.1 ft) east of the chain link fence
surrounding the property, and 19.82 m (65 ft) north of the centerline of the
main drive way entering the property. The datum point is set 17 cm (0.6 ft)
below grade, being the top of a stainless steel rod driven 15.8 m (52 ft) to
refusal, and encased in 5 inch PVC pipe.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8766072 PUBLICATION DATE: 04/28/2020
Name: FRESHWATER CANAL LOCKS
LA
NOAA Chart: 11354 Latitude: 29° 33.1' N ( 29.55169)
USGS Quad: POINT AU FER Longitude: 92° 18.3' W ( -92.30519)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 92
DESIGNATION: CORPS 92
MONUMENTATION: Bench Mark disk VM#: 21500
AGENCY: U.S. Army Corp of Engineers (USACE) IDB PID:
SETTING CLASSIFICATION: Metal rod OPUS PID:
LATITUDE: 29° 33.2' N ( 29.55286) LONGITUDE: 92° 18.3' W ( -92.30561)
The bench mark is a disk set in the gravel drive located on the south side of
the Army Corps of Engineeers property, 20.80 m (68.2 ft) West of bench mark 24R,
13.00 m (42.7 ft) SW of a metal fire hose enclosure labeled "Fire Station 1",
6.30 m (20.7 ft) south of the south edge of the paved road leading from the
property, 5.02 m (16.5 ft) east of the eastern corner of the small concrete pad
for the stair landing of an elevated gas tank platform, and 1.25 m (4.1 ft) SSW
of the second gate heading south along the canal. The bench mark is set 25 cm
(0.8 ft) below grade, crimped to a steel rod driven to unknown refusal, and has
a metal cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8766072 PUBLICATION DATE: 04/28/2020
Name: FRESHWATER CANAL LOCKS
LA
NOAA Chart: 11354 Latitude: 29° 33.1' N ( 29.55169)
USGS Quad: POINT AU FER Longitude: 92° 18.3' W ( -92.30519)
T I D A L D A T U M S
Tidal datums at FRESHWATER CANAL LOCKS based on:
LENGTH OF SERIES: 9 YEARS
TIME PERIOD: 4/2006-3/2008, 8/2008-7/2013, 7/2015-6/2017
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8770570 SABINE PASS NORTH
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (09/12/2008) = 3.072
MEAN HIGHER HIGH WATER MHHW = 0.636
MEAN HIGH WATER MHW = 0.590
MEAN TIDE LEVEL MTL = 0.372
North American Vertical Datum NAVD88 = 0.372
MEAN SEA LEVEL MSL = 0.365
MEAN LOW WATER MLW = 0.154
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (01/29/2019) = -0.973
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
6072 A 2005 2.484 1.894
24 R 2.255 1.665
6072 D 2009 1.569 0.979
6072 E 2015 1.492 0.902
92 1.621 1.031
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8766072 PUBLICATION DATE: 04/28/2020
Name: FRESHWATER CANAL LOCKS
LA
NOAA Chart: 11354 Latitude: 29° 33.1' N ( 29.55169)
USGS Quad: POINT AU FER Longitude: 92° 18.3' W ( -92.30519)
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.