U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 5
Station ID: 8726601 PUBLICATION DATE: 02/10/2005
Name: INDIAN ROCKS BEACH
FLORIDA
NOAA Chart: 11412 Latitude: 27° 52.4' N
USGS Quad: SEMINOLE Longitude: 82° 51.1' W
To reach the tidal bench marks from the Indian Rocks Bridge (State Road 694) in
Indian Rocks Beach proceed over The Narrows to the west end of the bridge. The
bench marks are located on the west end of the bridge and south along Gulf
Boulevard (State Road 699). The tide gage and staff were located on a private
dock at 32 Gulf Boulevard.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: BM 7 1972
DESIGNATION: 872 6625 TIDAL 7
MONUMENTATION: Tidal Station disk VM#: 6598
AGENCY: National Ocean Survey (NOS) PID#: AG7437
SETTING CLASSIFICATION: Concrete patio
The primary bench mark is a disk set flush in the SW corner of the concrete
patio at 30 Gulf Boulevard (Snelling residence), 58 m (190 ft) west of the
centerline of Gulf Boulevard and 11 m (37 ft) south of the centerline of the
wooden pier of the Snelling residence.
BENCH MARK STAMPING: BM 8 1972
DESIGNATION: 872 6601 TIDAL 8
MONUMENTATION: Survey disk VM#: 6599
AGENCY: US Coast and Geodetic Survey (USC&GS) PID:
SETTING CLASSIFICATION: Concrete monument
The bench mark is a disk set flush in a concrete monument in the NW corner of
the Sunset View Apartments (34 Gulf Boulevard) 16 m (52 ft) west of the north
wall of the apartments perpendicular to the beach, and 1 m (3 ft) SW of the SW
corner of the apartments parallel to the waterline. NOTE: Mark not recovered in
1982.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 5
Station ID: 8726601 PUBLICATION DATE: 02/10/2005
Name: INDIAN ROCKS BEACH
FLORIDA
NOAA Chart: 11412 Latitude: 27° 52.4' N
USGS Quad: SEMINOLE Longitude: 82° 51.1' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: BM 9 1972
DESIGNATION: 872 6601 TIDAL 9
MONUMENTATION: Survey disk VM#: 6600
AGENCY: US Coast and Geodetic Survey (USC&GS) PID:
SETTING CLASSIFICATION: Concrete sea wall
The bench mark is a disk set flush in a concrete sea wall, 70 m (230 ft) west of
the centerline of Gulf Boulevard where 5th Avenue ends and the beach access road
begins. NOTE: Mark not recovered in 1982.
BENCH MARK STAMPING: NO 4
DESIGNATION: 872 6601 TIDAL 4
MONUMENTATION: Tidal Station disk VM#: 6601
AGENCY: US Coast and Geodetic Survey (USC&GS) PID:
SETTING CLASSIFICATION: Concrete sea wall
The bench mark is a disk set in the top of a concrete monument at the NW corner
of a sea wall at an apartment house, 73 m (240 ft) south of the post office, 58
m (190 ft) west of the centerline of Gulf Boulevard, 21 m (68 ft) WNW of the NW
corner of a small stucco house at 42 Gulf Boulevard, and 1.10 m (3.6 ft) above
ground level.
BENCH MARK STAMPING:
DESIGNATION: 10 FSRD
ALIAS: NO STAMPING 1
MONUMENTATION: Survey disk VM#: 6602
AGENCY: Florida Department of Transportation (FLDT)PID:
SETTING CLASSIFICATION: Concrete bridge abutment
The bench mark is a disk set flush in the SW corner of the Indian Rocks bridge,
25 m (82 ft) east of the gate on the west end of the bridge.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 5
Station ID: 8726601 PUBLICATION DATE: 02/10/2005
Name: INDIAN ROCKS BEACH
FLORIDA
NOAA Chart: 11412 Latitude: 27° 52.4' N
USGS Quad: SEMINOLE Longitude: 82° 51.1' W
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: NARROW NO 1 1973
DESIGNATION: NARROW RM 1
MONUMENTATION: Reference Mark disk VM#: 17259
AGENCY: National Geodetic Survey (NGS) PID#: AG0716
SETTING CLASSIFICATION: Concrete sea wall
The bench mark is a disk set in the top of a concrete sea wall on the west shore
of The Narrows, 59 m (193 ft) SSE of the NE corner of the Fifty Gulfside
Condominiums at #50 Gulf Boulevard, and 18 m (60 ft) east of the centerline of
Gulf Boulevard.
BENCH MARK STAMPING: R 84 PNLS 1974
DESIGNATION: R 84 PNLS FLDNR
MONUMENTATION: Survey disk VM#: 17260
AGENCY: Florida Department of Natural Resources (FLDNR)PID#: AG0813
SETTING CLASSIFICATION: Concrete monument
The bench mark is a disk set in the top of a concrete monument, 53 m (173 ft)
west of the centerline of Gulf Boulevard, 35 m (114 ft) NW of the NE corner of
the Fifty Gulfside Condominiums at #50 Gulf Boulevard, 9 m (30 ft) NW of power
line pole #110723, 7 m (24 ft) west of the SW corner of the Happy Fiddler
Condominiums, 0.15 m (0.5 ft) south of the SW corner of a sea wall, and at
ground level.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 5
Station ID: 8726601 PUBLICATION DATE: 02/10/2005
Name: INDIAN ROCKS BEACH
FLORIDA
NOAA Chart: 11412 Latitude: 27° 52.4' N
USGS Quad: SEMINOLE Longitude: 82° 51.1' W
T I D A L D A T U M S
Tidal datums at INDIAN ROCKS BEACH based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: May 1973 - May 1973
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) = 0.776
MEAN HIGH WATER (MHW) = 0.658
NORTH AMERICAN VERTICAL DATUM-1988 (NAVD) = 0.524
MEAN TIDE LEVEL (MTL) = 0.406
MEAN LOW WATER (MLW) = 0.154
MEAN LOWER LOW WATER (MLLW) = 0.000
National Geodetic Vertical Datum (NGVD 29)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
BM 7 1972 2.725 2.067
BM 8 1972 3.257 2.599
BM 9 1972 3.141 2.483
NO 4 3.138 2.480
10 FSRD 8.287 7.629
NARROW NO 1 1973 1.512 0.854
R 84 PNLS 1974 2.755 2.097
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 5
Station ID: 8726601 PUBLICATION DATE: 02/10/2005
Name: INDIAN ROCKS BEACH
FLORIDA
NOAA Chart: 11412 Latitude: 27° 52.4' N
USGS Quad: SEMINOLE Longitude: 82° 51.1' 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.