U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Datums Page Page 1 of 6
Station ID: 8725985 PUBLICATION DATE: 06/29/2011
Name: SIESTA KEY, LITTLE SARASOTA BAY
FL
NOAA Chart: 11424 Latitude: 27° 13.3' N ( 27.22170)
USGS Quad: BIRD KEYS Longitude: 82° 30.9' W ( -82.51500)
To reach the tidal bench marks from the intersection of U.S. Highway 41 (South
Tamiami Trail) and State Highway 72 (Stickney Point Road), proceed west on
Stickney Point Road for 1.6 km (1.0 mi) to its intersection with State Road 789
(Midnight Pass Road), then turn left and proceed south on Midnight Pass Road for
4.3 km (2.7 mi) to the Midnight Pass Marina. The bench marks are located around
the marina. The tide gage and staff were located on the Midnight Pass Marina
Pier.
T I D A L B E N C H M A R K S
PRIMARY BENCH MARK STAMPING: 5985 A 1977
DESIGNATION: 872 5985 A TIDAL
MONUMENTATION: Tidal Station disk VM#: 6107
AGENCY: National Ocean Survey (NOS) IDB PID#: AG7644
SETTING CLASSIFICATION: Concrete sea wall OPUS PID#: AG7644
LATITUDE: 27° 13.2' N ( 27.22000) LONGITUDE: 82° 30.9' W ( -82.51500)
The primary bench mark is a disk set flush in a sea wall, 11.77 m (38.6 ft) west
of the east end of the boat lift, 9.42 m (30.9 ft) north of the south end of the
seawall, and 3.66 m (12.0 ft) south of the center of the boat lift. NOTE: US
Power Squadron recovered mark in poor condition in 1997.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 2 of 6
Station ID: 8725985 PUBLICATION DATE: 06/29/2011
Name: SIESTA KEY, LITTLE SARASOTA BAY
FL
NOAA Chart: 11424 Latitude: 27° 13.3' N ( 27.22170)
USGS Quad: BIRD KEYS Longitude: 82° 30.9' W ( -82.51500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5985 B 1977
DESIGNATION: 872 5985 B TIDAL
MONUMENTATION: Tidal Station disk VM#: 6108
AGENCY: National Ocean Survey (NOS) IDB PID#: AG7643
SETTING CLASSIFICATION: Concrete sea wall OPUS PID#: AG7643
LATITUDE: 27° 13.2' N ( 27.22000) LONGITUDE: 82° 30.9' W ( -82.51500)
The bench mark is a disk set flush in a sea wall, 11.95 m (39.2 ft) west of the
east end of the concrete rail of the boat lift, 6.92 m (22.7 ft) north of Bench
Mark 5985 A 1977, 6.83 m (22.4 ft) south of the north end of the seawall, and
2.19 m (7.2 ft) north of the center of the boat lift.
BENCH MARK STAMPING: 5985 C 1977
DESIGNATION: 872 5985 C TIDAL
MONUMENTATION: Tidal Station disk VM#: 6109
AGENCY: National Ocean Survey (NOS) IDB PID#: AG7642
SETTING CLASSIFICATION: Concrete sea wall OPUS PID:
LATITUDE: 27° 13.2' N ( 27.22000) LONGITUDE: 82° 30.8' W ( -82.51330)
The bench mark is a disk set flush in a sea wall, 48.46 m (159.0 ft) NE of Bench
Mark 5985 E 1977, 17.68 m (58.0 ft) west of Bench Mark 5985 B 1977, 7.62 m (25.0
ft) east of the NE corner of the office building, 6 m (20 ft) south of the north
end of the seawall, and 1.83 m (6.0 ft) south of the SW corner of the wooden
shed.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 3 of 6
Station ID: 8725985 PUBLICATION DATE: 06/29/2011
Name: SIESTA KEY, LITTLE SARASOTA BAY
FL
NOAA Chart: 11424 Latitude: 27° 13.3' N ( 27.22170)
USGS Quad: BIRD KEYS Longitude: 82° 30.9' W ( -82.51500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: 5985 H 2008
DESIGNATION: 872 5985 H TIDAL
MONUMENTATION: Survey disk VM#: 19938
AGENCY: Florida Dept. of Environmental
Protection (FLDEP) IDB PID#: DL1850
SETTING CLASSIFICATION: Concrete base of flag pole OPUS PID:
LATITUDE: 27° 13.2' N ( 27.21922) LONGITUDE: 82° 30.9' W ( -82.51556)
The bench mark is a disk set flush in the top of the concrete base of a large
flag pole and level with Midnight pass road, about 31.1 m (102.0 ft) west of
bench mark 5985 G 1983, 22.6 m (74.2 ft) west of the centerline of Midnight Pass
Road, 16.9 m (55.6 ft) south of the centerline of Turtle Beach Road, 13.3 m
(43.7 ft) north of the NE corner of the beach restrooms building, 12.1 m (39.6
ft) east of the east edge of a 1.2 m (4.0 ft) concrete sidewalk leading to the
restrooms, and 0.3 m (1.0 ft) south of the flag pole.
BENCH MARK STAMPING: 17 84 A35 REF MK 2
DESIGNATION: 17 84 A35 RM 2
MONUMENTATION: Survey disk VM#: 19939
AGENCY: Florida Department of Transportation
(FLDT) IDB PID#: DL1867
SETTING CLASSIFICATION: Concrete pad OPUS PID:
LATITUDE: 27° 14.8' N ( 27.24611) LONGITUDE: 82° 31.8' W ( -82.53056)
The bench mark is a disk set flush in the top of a concrete pad supporting a GTE
Telephone cable box and 0.2 m (0.6 ft) below the level of midnight pass road,
12.4 m (40.6 ft) west of the centerline of Midnight pass road, 4.2 m (13.9 ft)
north of the centerline of Crescent Street, 4.1 m (13.5 ft) SW of the street
sign, 2.3 m (7.5 ft) SE of a wooden power pole numbered 1149, and 0.5 m (1.6 ft)
south of the south face of the GTE cable box.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 4 of 6
Station ID: 8725985 PUBLICATION DATE: 06/29/2011
Name: SIESTA KEY, LITTLE SARASOTA BAY
FL
NOAA Chart: 11424 Latitude: 27° 13.3' N ( 27.22170)
USGS Quad: BIRD KEYS Longitude: 82° 30.9' W ( -82.51500)
T I D A L B E N C H M A R K S
BENCH MARK STAMPING: B 715 2008
DESIGNATION: B 715
MONUMENTATION: Survey disk VM#: 19940
AGENCY: Florida Department of Transportation
(FLDT)st IDB PID#: DL1849
SETTING CLASSIFICATION: Stainless steel rod OPUS PID:
LATITUDE: 27° 14.0' N ( 27.23361) LONGITUDE: 82° 31.3' W ( -82.52139)
The bench mark is a stainless steel rod located about 21.3 m (70.0 ft) SE of the
extended centerline of Mandalay Point Lane, 8.6 m (28.1 ft) west of the
centerline of Midnight Pass Road, 2.2 m (7.2 ft) south-SE of the centerline of
the south end of an asphalt circular drive of the Cutter residence at 8118
Midnight Pass Road, 1.7 m (5.5 ft) NW of a wooden power pole numbered 8124, 1.6
m (5.4 ft) NW of a carsonite witness post, and 0.7 m (2.3 ft) north of the face
of a 2.7 m (9.0 ft)stucco wall. The bench mark is a stainless steel rod driven
to refusal at a depth of 12.1 m (39.6 ft) with a NGS logo cap recessed 0.03 m
(0.1 ft) below the level of the ground and 0.18 m (0.6 ft) below the level of
Midnight Pass Road, the datum point being recessed 0.06 m (0.2 ft) below the
level of the NGS logo cap.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 5 of 6
Station ID: 8725985 PUBLICATION DATE: 06/29/2011
Name: SIESTA KEY, LITTLE SARASOTA BAY
FL
NOAA Chart: 11424 Latitude: 27° 13.3' N ( 27.22170)
USGS Quad: BIRD KEYS Longitude: 82° 30.9' W ( -82.51500)
T I D A L D A T U M S
Tidal datums at SIESTA KEY, LITTLE SARASOTA BAY based on:
LENGTH OF SERIES: 1 MONTH
TIME PERIOD: October 1977 - October 1977
TIDAL EPOCH: 1983-2001
CONTROL TIDE STATION: 8725943 BLACKBURN POINT
Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:
MEAN HIGHER HIGH WATER MHHW = 0.540
MEAN HIGH WATER MHW = 0.451
North American Vertical Datum NAVD88 = 0.414
MEAN TIDE LEVEL MTL = 0.283
MEAN SEA LEVEL MSL = 0.275
MEAN LOW WATER MLW = 0.115
MEAN LOWER LOW WATER MLLW = 0.000
North American Vertical Datum (NAVD88)
Bench Mark Elevation Information In METERS above:
Stamping or Designation MLLW MHW
5985 A 1977 1.230 0.779
5985 B 1977 1.220 0.769
5985 C 1977 1.245 0.794
5985 H 2008 1.649 1.198
17 84 A35 REF MK 2 1.629 1.178
B 715 2008 1.309 0.858
Foot Notes:
Bench marks 17 84 A35 REF MK 2, 5985 H 2008, and B 715 2008 are based on one
differential leveling connection and do not meet the quality control standards
of the NOS. Therefore, caution should be used when deriving elevations for
these marks.
U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
National Ocean Service
Page 6 of 6
Station ID: 8725985 PUBLICATION DATE: 06/29/2011
Name: SIESTA KEY, LITTLE SARASOTA BAY
FL
NOAA Chart: 11424 Latitude: 27° 13.3' N ( 27.22170)
USGS Quad: BIRD KEYS Longitude: 82° 30.9' W ( -82.51500)
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.