U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8773259 PUBLICATION DATE: 12/08/2020
Name: PORT LAVACA, LAVACA CAUSEWAY
TX
NOAA Chart: 11317 Latitude: 28° 38.4' N ( 28.64060)
USGS Quad: CALHOUN Longitude: 96° 36.6' W ( -96.60980)
To reach the station from the intersection of HWY 87 and HWY 35 in Port Lavaca,
Texas, travel north on HWY 35 for 4.48 km (2.78 mi), turn right on Broadway St.
and proceed 0.14 km (0.09 mi) to the entrance of the county park. The bench
marks are located inside the park, in the vicinty of the boat ramp. The tide
station is located on the state fishing pier in Port Lavaca, Texas, 91.4 m
(299.9 ft) bayward of the public restrooms at the foot of the pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: GLO 2
DESIGNATION: 877 3259 GLO-2
MONUMENTATION: Bench Mark disk VM#: 9492
AGENCY: Texas General Land Office (TGLO) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 28° 38.3' N ( 28.63914) LONGITUDE: 96° 36.8' W ( -96.61292)
The primary benchmark is located 71.6 M ( 234.9 FT) W of the N corner of the
boat ramp, 59.8 M (192.2 FT) N of the N corner of a restroom building along the
main road, 23.8 M (78.1 FT) SSE of a lightpole S of HWY 35, 21.4 M (70.2 FT) NNW
of the W corner of the parking lot, the primary benchmark is a brass disc set
atop a stainless-steel rod driven 13.7 M (45 FT) to refusal and encased in a
6-inch PVC pipe without a kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8773259 PUBLICATION DATE: 12/08/2020
Name: PORT LAVACA, LAVACA CAUSEWAY
TX
NOAA Chart: 11317 Latitude: 28° 38.4' N ( 28.64060)
USGS Quad: CALHOUN Longitude: 96° 36.6' W ( -96.60980)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: GLO 3
DESIGNATION: 877 3259 GLO-3
MONUMENTATION: Tidal Station disk VM#: 9493
AGENCY: Texas General Land Office (TGLO) IDB PID:
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 28° 38.3' N ( 28.63836) LONGITUDE: 96° 36.8' W ( -96.61269)
The mark is located between the park road leading to the pier and covered
campsite 13 on the E side of the road, 90 M (295.3 FT) S of BM GLO 2, 10.3 M
(33.8 FT) W of the WNW edge of #43 campsite, 9.5 M (31.2 FT) ESE of the center
of the road, 4.9 M (16.1 FT) S of the W corner of driveway site #44. The
benchmark is a brass disk set atop a stainless-steel rod driven 13.7 M (45 FT)
to refusal and encased in a 6-inch PVC pipe without a kickblock.
BENCH MARK STAMPING: 3259 A 2006
DESIGNATION: 877 3259 A
MONUMENTATION: Bench Mark disk VM#: 22122
AGENCY: Conrad Blucher Institute (CBI) IDB PID:
SETTING CLASSIFICATION: OPUS PID:
LATITUDE: 28° 38.4' N ( 28.63986) LONGITUDE: 96° 36.6' W ( -96.61064)
The bench mark is a brass disk set in the concrete sidewalk leading to the
fishing pier, located on the south side at the base of the pier, 19.5 m (64.0
ft) ESE of SE edge of the boat ramp channel, 11.55 m (37.89 ft) SW of the east
corner of the restrooms, and 1.5 m (4.9 ft) SSE of the centerline of the
sidewalk leading to the pier.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8773259 PUBLICATION DATE: 12/08/2020
Name: PORT LAVACA, LAVACA CAUSEWAY
TX
NOAA Chart: 11317 Latitude: 28° 38.4' N ( 28.64060)
USGS Quad: CALHOUN Longitude: 96° 36.6' W ( -96.60980)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 3259 B 2018
DESIGNATION: 877 3259 B
MONUMENTATION: Bench Mark disk VM#: 22859
AGENCY: Conrad Blucher Institute (CBI) IDB PID:
SETTING CLASSIFICATION: Concrete pad OPUS PID:
LATITUDE: 28° 38.3' N ( 28.63819) LONGITUDE: 96° 36.8' W ( -96.61375)
The bench mark is a disk located in the SW corner of covered picnic area 6,
32.0m (104.9 ft) WNW of the center line of the main park road, 29.0m (95.1 ft)
north of non-potable water station, and 19.0m (62.3 ft) NNW of the light pole
next to the sewer cover.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8773259 PUBLICATION DATE: 12/08/2020
Name: PORT LAVACA, LAVACA CAUSEWAY
TX
NOAA Chart: 11317 Latitude: 28° 38.4' N ( 28.64060)
USGS Quad: CALHOUN Longitude: 96° 36.6' W ( -96.60980)
T I D A L D A T U M S
Tidal datums at PORT LAVACA, LAVACA CAUSEWAY based on:
LENGTH OF SERIES: 3 YEARS
TIME PERIOD: 8/15-7/16, 2/17-1/19
TIDAL EPOCH: 2002-2006
CONTROL TIDE STATION: 8773701 PORT O'CONNOR, MATAGORDA BAY
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (08/26/2017) = 2.335
MEAN HIGHER HIGH WATER MHHW = 0.273
MEAN HIGH WATER MHW = 0.264
MEAN SEA LEVEL MSL = 0.150
MEAN TIDE LEVEL MTL = 0.141
MEAN LOW WATER MLW = 0.017
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (01/12/2018) = -0.587
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
GLO 2 1.367 1.103
GLO 3 1.280 1.016
3259 A 2006 1.318 1.054
3259 B 2018 1.674 1.410
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8773259 PUBLICATION DATE: 12/08/2020
Name: PORT LAVACA, LAVACA CAUSEWAY
TX
NOAA Chart: 11317 Latitude: 28° 38.4' N ( 28.64060)
USGS Quad: CALHOUN Longitude: 96° 36.6' W ( -96.60980)
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.