U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8726774 PUBLICATION DATE: 04/29/2004 Name: CALADESI ISLAND, INSIDE FL NOAA Chart: 11412 Latitude: 28° 1.9' N ( 28.03170) USGS Quad: DUNEDIN Longitude: 82° 49.2' W ( -82.82000) To reach the tidal bench marks from Dunedin City Marina, proceed by boat or ferry to Caladesi Island State Park. The bench marks are located around the State Park. The tide gage and staff were located on the pier behind the boat house. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 6774 C 1976 DESIGNATION: 872 6774 C MONUMENTATION: Tidal Station disk VM#: 7587 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 28° 1.9' N ( 28.03170) LONGITUDE: 82° 49.2' W ( -82.82000) The primary bench mark is a disk located 19.57 m (64.2 ft) south of the SW corner of a boat basin, and 0.64 m (2.1 ft) south of power pole #210752. The bench mark is level with the ground, crimped to a copper-clad steel rod driven an unspecified depth 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 2 of 5 Station ID: 8726774 PUBLICATION DATE: 04/29/2004 Name: CALADESI ISLAND, INSIDE FL NOAA Chart: 11412 Latitude: 28° 1.9' N ( 28.03170) USGS Quad: DUNEDIN Longitude: 82° 49.2' W ( -82.82000) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 6774 D 1976 DESIGNATION: 872 6774 D MONUMENTATION: Tidal Station disk VM#: 7588 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 28° 1.9' N ( 28.03170) LONGITUDE: 82° 49.2' W ( -82.82000) The bench mark is a disk located 15.48 m (50.8 ft) west of the NW corner of the marina basin. The bench mark is 0.61 m (2.0 ft) below ground level, crimped to the top of a copper-clad steel rod driven an unspecified depth to refusal, and encased in a PVC pipe and concrete kickblock. NOTE: The mark was searched for but not found by FLDNR in 1983. The area is buried under about 1 m (3 ft) of fill.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 8726774 PUBLICATION DATE: 04/29/2004 Name: CALADESI ISLAND, INSIDE FL NOAA Chart: 11412 Latitude: 28° 1.9' N ( 28.03170) USGS Quad: DUNEDIN Longitude: 82° 49.2' W ( -82.82000) T I D A L B E N C H M A R K S BENCH MARK STAMPING: R23 1974 DESIGNATION: R23 MONUMENTATION: Survey disk VM#: 7589 AGENCY: Florida Department of Natural Resources (FLDNR) IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 28° 1.9' N ( 28.03170) LONGITUDE: 82° 49.2' W ( -82.82000) The bench mark is a disk set in the top of a concrete monument, 88 m (288 ft) west of Bench Mark 6774 D 1976, 17.13 m (56.2 ft) west of a sand dune information sign, 0.76 m (2.5 ft) ESE of a metal witness post, and at ground level. BENCH MARK STAMPING: 6774 A 1976 DESIGNATION: 872 6774 A MONUMENTATION: Tidal Station disk VM#: 17161 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete pad OPUS PID: LATITUDE: 28° 1.9' N ( 28.03170) LONGITUDE: 82° 49.2' W ( -82.82000) The bench mark is a disk set in the concrete pad for the eastern boat davit at the boat house, 1.98 m (6.5 ft) NW of the corner of a 2 m (6 ft) high fence, 1.43 m (4.7 ft) south of the sea wall, and 0.55 m (1.8 ft) east of the SE brace for the davit. NOTE: The mark was destroyed by the construction of a new sea wall, 7/1/1980.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 8726774 PUBLICATION DATE: 04/29/2004 Name: CALADESI ISLAND, INSIDE FL NOAA Chart: 11412 Latitude: 28° 1.9' N ( 28.03170) USGS Quad: DUNEDIN Longitude: 82° 49.2' W ( -82.82000) T I D A L D A T U M S Tidal datums at CALADESI ISLAND, INSIDE based on: LENGTH OF SERIES: 1 MONTH TIME PERIOD: March 1976 - March 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 = 0.880 MEAN HIGH WATER MHW = 0.773 MEAN SEA LEVEL MSL = 0.468 MEAN TIDE LEVEL MTL = 0.465 MEAN LOW WATER MLW = 0.157 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 6774 C 1976 1.666 0.893 6774 D 1976 2.085 1.312 R23 1974 1.954 1.181 6774 A 1976 1.684 0.911
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8726774 PUBLICATION DATE: 04/29/2004 Name: CALADESI ISLAND, INSIDE FL NOAA Chart: 11412 Latitude: 28° 1.9' N ( 28.03170) USGS Quad: DUNEDIN Longitude: 82° 49.2' W ( -82.82000) 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.