U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8727274 PUBLICATION DATE: 09/15/2004
Name: MASON CREEK, HOMOSASSA BAY
FL
NOAA Chart: 11409 Latitude: 28° 45.7' N ( 28.76170)
USGS Quad: OZELLO Longitude: 82° 38.3' W ( -82.63830)
To reach the tidal bench marks from the intersection of State Road 490 and Mason
Creek Road, across from the Homosassa Elementary School, proceed SW on Mason
Creek Road for 2.9 km (1.8 mi) to Standish Drive, then west and south on
Standish Drive for 0.6 km (0.4 mi). The bench marks are located near the end of
Mason Creek Road and along Standish Drive. The tide gage and staff were located
on a private boat dock in Mason Creek behind the house at Route 5 Box 52F.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: NO 1 1973
DESIGNATION: 872 7274 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 7760
AGENCY: National Ocean Survey (NOS) IDB PID#: AL7297
SETTING CLASSIFICATION: Concrete patio OPUS PID:
LATITUDE: 28° 45.6' N ( 28.76000) LONGITUDE: 82° 38.2' W ( -82.63670)
The primary bench mark is a disk set in the top of a concrete patio at the last
residence on the north side of Mason Creek Road, 0.3 km (0.2 mi) NW of the dead
end of Mason Creek Road, 5 m (18 ft) NW of the pier walkway, and 5 m (15 ft)
west of the west corner of the house.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8727274 PUBLICATION DATE: 09/15/2004
Name: MASON CREEK, HOMOSASSA BAY
FL
NOAA Chart: 11409 Latitude: 28° 45.7' N ( 28.76170)
USGS Quad: OZELLO Longitude: 82° 38.3' W ( -82.63830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 2 1973
DESIGNATION: 872 7274 TIDAL 2
MONUMENTATION: Tidal Station disk VM#: 7761
AGENCY: National Ocean Survey (NOS) IDB PID#: AL7296
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 28° 45.6' N ( 28.76000) LONGITUDE: 82° 38.2' W ( -82.63670)
The bench mark is a disk set in the top of a concrete seawall at the corner of
the curved section of the seawall located on the SE side of the last residence
on the north side of Mason Creek Road, 15 m (50 ft) SE of the pier walkway, 10 m
(33 ft) SW of the east corner of the house, 4 m (12 ft) from the south corner of
the house, and 0.03 m (0.1 ft) below ground level.
BENCH MARK STAMPING: NO 3 1973
DESIGNATION: 872 7274 TIDAL 3
MONUMENTATION: Tidal Station disk VM#: 7762
AGENCY: National Ocean Survey (NOS) IDB PID#: AL7293
SETTING CLASSIFICATION: Boulder OPUS PID:
LATITUDE: 28° 45.7' N ( 28.76170) LONGITUDE: 82° 38.0' W ( -82.63330)
The bench mark is a disk set in the top of the largest coral boulder loacated at
the dead end of Mason Creek Road, 17 m (55 ft) east of the centerline of a
concrete boat ramp, and 9.14 m (30.0 ft) north of the shoreline of Mason Creek.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8727274 PUBLICATION DATE: 09/15/2004
Name: MASON CREEK, HOMOSASSA BAY
FL
NOAA Chart: 11409 Latitude: 28° 45.7' N ( 28.76170)
USGS Quad: OZELLO Longitude: 82° 38.3' W ( -82.63830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NO 4 1973
DESIGNATION: 872 7274 TIDAL 4
MONUMENTATION: Tidal Station disk VM#: 7763
AGENCY: National Ocean Survey (NOS) IDB PID#: AL7292
SETTING CLASSIFICATION: Boulder OPUS PID:
LATITUDE: 28° 45.8' N ( 28.76330) LONGITUDE: 82° 38.0' W ( -82.63330)
The bench mark is a disk set in the top of a boulder located at the SE corner of
the junction Mason Creek Road and Cedar Gate Road, 0.08 km (0.05 mi) SW of the
junctio of Standish Drive, 17 m (55 ft) SE of powerline pole No. 74, 8 m (25 ft)
east of the centerline of Mason Creek Road, 6 m (20 ft) south of the centerline
of Cedar Gate Road, and 4 m (13 ft) west of a square concrete corner post
BENCH MARK STAMPING: NO 5 1973
DESIGNATION: 872 7274 TIDAL 5
MONUMENTATION: Tidal Station disk VM#: 7764
AGENCY: National Ocean Survey (NOS) IDB PID#: AL7295
SETTING CLASSIFICATION: Concrete footing OPUS PID:
LATITUDE: 28° 45.7' N ( 28.76170) LONGITUDE: 82° 38.2' W ( -82.63670)
The bench mark is a disk set in the top center of a concrete footing at the east
corner of the concrete drive to the garage and concrete walkway around the last
residence on the north side of Mason Creek Road,and 1 m (3 ft) north of the
house.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8727274 PUBLICATION DATE: 09/15/2004
Name: MASON CREEK, HOMOSASSA BAY
FL
NOAA Chart: 11409 Latitude: 28° 45.7' N ( 28.76170)
USGS Quad: OZELLO Longitude: 82° 38.3' W ( -82.63830)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 6 1975
DESIGNATION: 872 7274 TIDAL 6
MONUMENTATION: Tidal Station disk VM#: 11260
AGENCY: National Ocean Survey (NOS) IDB PID#: AL7294
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID:
LATITUDE: 28° 45.7' N ( 28.76170) LONGITUDE: 82° 38.1' W ( -82.63500)
The bench mark is a disk located 12 m (41 ft) east of a palm tree, 9 m (31 ft)
NE of the center of a concrete well, 9 m (28 ft) south of the dirt driveway to
the last residence on the north side of Mason Creek Road, and 2 m (6 ft) NW of a
powerline pole. The bench mark is set 30 cm (1 ft) above the ground, crimped to
the top of a copper-clad rod driven 4.9 m (16 ft) to refusal, and encased in a
PVC pipe and concrete kickblock.
BENCH MARK STAMPING: 7274 A 1976
DESIGNATION: 872 7274 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 11261
AGENCY: National Ocean Survey (NOS) IDB PID#: AL7298
SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID#: AL7298
LATITUDE: 28° 45.7' N ( 28.76170) LONGITUDE: 82° 38.3' W ( -82.63830)
The bench mark is a disk located 39 m (129 ft) east of the centerline of the
intersection of Battle Creek Road and Standish Drive, 5.03 m (16.5 ft) south of
the centerline of Standish Drive, 4.63 m (15.2 ft) NNW of the NW corner of a
cinder block house (Rt. 5 Box 52f), and 0.52 m (1.7 ft) west of utility pole
CR-171-RR-1-28. The bench mark is set at ground level, crimped to the top of a
copper-clad steel rod driven 4.9 m (16 ft) to refusal, and encased in a PVC pipe
and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8727274 PUBLICATION DATE: 09/15/2004
Name: MASON CREEK, HOMOSASSA BAY
FL
NOAA Chart: 11409 Latitude: 28° 45.7' N ( 28.76170)
USGS Quad: OZELLO Longitude: 82° 38.3' W ( -82.63830)
T I D A L D A T U M S
Tidal datums at MASON CREEK, HOMOSASSA BAY based on:
LENGTH OF SERIES: 1 YEAR
TIME PERIOD: March 1978 - February 1979
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8727520 CEDAR KEY, GULF OF MEXICO
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
HIGHEST OBSERVED WATER LEVEL (05/28/1973) = 1.528
MEAN HIGHER HIGH WATER MHHW = 0.412
MEAN HIGH WATER MHW = 0.341
MEAN TIDE LEVEL MTL = 0.195
North American Vertical Datum NAVD88 = 0.191
MEAN SEA LEVEL MSL = 0.181
MEAN LOW WATER MLW = 0.048
MEAN LOWER LOW WATER MLLW = 0.000
LOWEST OBSERVED WATER LEVEL (05/04/1973) = -0.447
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
NO 1 1973 1.337 0.996
NO 2 1973 1.292 0.951
NO 3 1973 2.235 1.894
NO 4 1973 2.088 1.747
NO 5 1973 1.319 0.978
6 1975 1.497 1.156
7274 A 1976 1.091 0.750
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8727274 PUBLICATION DATE: 09/15/2004
Name: MASON CREEK, HOMOSASSA BAY
FL
NOAA Chart: 11409 Latitude: 28° 45.7' N ( 28.76170)
USGS Quad: OZELLO Longitude: 82° 38.3' W ( -82.63830)
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.