U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8726706 PUBLICATION DATE: 04/29/2004
Name: CLEARWATER, CLEARWATER HARBOR
FL
NOAA Chart: 11410 Latitude: 27° 57.3' N ( 27.95500)
USGS Quad: CLEARWATER Longitude: 82° 48.4' W ( -82.80670)
To reach the tidal bench marks from the intersection of U.S. Alternate Highway
19 (Fort Harrison Avenue) and State Road 697 (Bellview Avenue), proceed west on
Bellview Avenue for 0.6 km (0.4 mi) to Druid Road South, then north on Druid
Road South for 1.3 km (0.8 mi) to Magnolia Road, then west on Magnolia Road to
its end. The bench marks are along Magnolia Road and Druid Road South. The
tide gage and staff were on the pier at the end of Magnolia Road.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: TBM NO 1 1949
DESIGNATION: 872 6706 TIDAL 1
MONUMENTATION: Tidal Station disk VM#: 6786
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AG0992
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 27° 57.2' N ( 27.95330) LONGITUDE: 82° 48.4' W ( -82.80670)
The primary bench mark is a disk set on a concrete sea wall at the foot of the
west end of Magnolia Road, 6.98 m (22.9 ft) south of the south hand rail of the
walkway to the Harbor Oaks Pier, 8.84 m (29.0 ft) south of the extended
centerline of Magnolia Road, and 6.10 m (20.0 ft) ESE of powerline pole
#6A-11314, and 0.49 m (1.6 ft) north of the concrete wall.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8726706 PUBLICATION DATE: 04/29/2004
Name: CLEARWATER, CLEARWATER HARBOR
FL
NOAA Chart: 11410 Latitude: 27° 57.3' N ( 27.95500)
USGS Quad: CLEARWATER Longitude: 82° 48.4' W ( -82.80670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: TBM NO 2 1949
DESIGNATION: 872 6706 TIDAL 2
MONUMENTATION: Tidal Station disk VM#: 6787
AGENCY: US Coast and Geodetic Survey
(USC&GS) IDB PID#: AG0998
SETTING CLASSIFICATION: Concrete curb OPUS PID:
LATITUDE: 27° 57.2' N ( 27.95330) LONGITUDE: 82° 48.4' W ( -82.80670)
The bench mark is a disk set in the north curb at the west end of Magnolia Road,
6.55 m (21.5 ft) east of the edge of the sea wall, 7.19 m (23.6 ft) north of the
centerline of Magnolia Road, and 3.57 m (11.7 ft) west of the centerline of the
driveway.
BENCH MARK STAMPING: NO 5 1975
DESIGNATION: 872 6706 TIDAL 5
MONUMENTATION: Bench Mark disk VM#: 6788
AGENCY: National Ocean Survey (NOS) IDB PID#: AG1003
SETTING CLASSIFICATION: Concrete curb OPUS PID:
LATITUDE: 27° 57.2' N ( 27.95330) LONGITUDE: 82° 48.3' W ( -82.80500)
The bench mark is a disk set in the curb at the SE corner of the intersection of
Magnolia Road and Druid Road, 10.45 m (34.3 ft) east of the centerline of Druid
Road, 3 m (10 ft) south of the centerline of Magnolia Road, and 6.71 m (22.0 ft)
NNE of a 1 m (2 ft) diameter oak tree. NOTE: Mark not found in 1996 by US Power
Squadron.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8726706 PUBLICATION DATE: 04/29/2004
Name: CLEARWATER, CLEARWATER HARBOR
FL
NOAA Chart: 11410 Latitude: 27° 57.3' N ( 27.95500)
USGS Quad: CLEARWATER Longitude: 82° 48.4' W ( -82.80670)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: HARRIS O
DESIGNATION: HARRIS O
MONUMENTATION: Survey disk VM#: 6789
AGENCY: Pinellas County (FL-103) IDB PID#: AG0586
SETTING CLASSIFICATION: Concrete monument OPUS PID:
LATITUDE: 27° 57.3' N ( 27.95500) LONGITUDE: 82° 48.3' W ( -82.80500)
The bench mark is a disk set in the top of a concrete monument, 1 block south of
bench mark NO 5 1975, 10.36 m (34.0 ft) south of the centerline of Lotus Path,
4.24 m (13.9 ft) west of the centerline of Druid Road, and 0.79 m (2.6 ft) WSW
of a witness post.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8726706 PUBLICATION DATE: 04/29/2004
Name: CLEARWATER, CLEARWATER HARBOR
FL
NOAA Chart: 11410 Latitude: 27° 57.3' N ( 27.95500)
USGS Quad: CLEARWATER Longitude: 82° 48.4' W ( -82.80670)
T I D A L D A T U M S
Tidal datums at CLEARWATER, CLEARWATER HARBOR based on:
LENGTH OF SERIES: 11 MONTHS
TIME PERIOD: November 1975 - September 1976
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8726724 CLEARWATER BEACH, GULF OF MEXICO
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.836
MEAN HIGH WATER MHW = 0.730
North American Vertical Datum NAVD88 = 0.535
MEAN SEA LEVEL MSL = 0.445
MEAN TIDE LEVEL MTL = 0.442
MEAN LOW WATER MLW = 0.154
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
TBM NO 1 1949 1.364 0.634
TBM NO 2 1949 1.509 0.779
NO 5 1975 8.781 8.051
HARRIS O 7.772 7.042
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8726706 PUBLICATION DATE: 04/29/2004
Name: CLEARWATER, CLEARWATER HARBOR
FL
NOAA Chart: 11410 Latitude: 27° 57.3' N ( 27.95500)
USGS Quad: CLEARWATER Longitude: 82° 48.4' W ( -82.80670)
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.