U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 PUBLICATION DATE: 04/06/1984 Station ID: 8729747 SUPERCEDED DATE: 04/21/2003 Name: SHIELDS POINT, BLACKWATER BAY FLORIDA NOAA Chart: 11382 Latitude: 30° 34.9' N USGS Quad: MILTON SOUTH Longitude: 87° 0.9' W To reach the tidal bench marks proceed from the intersection of State Highway 191 and U.S. Highway 90 to Highway 191C, south for 2.6 miles (4.2 km), on State Highway 191, SE on Highway 191C for 0.9 mile (1.4 km), to the overpass over Interstate 10, then first left and follow the paved drive 0.5 mile (0.8 km), to the Presley Residence. The bench marks are located along Interstate 10 and the Presley property and the tide gage and staff were located on a wooden dock behind the Presley property. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: NO 2 1976 MONUMENTATION: Survey Disk VM#: 10220 AGENCY: PID#: BG4533 SETTING CLASSIFICATION: Copper-Clad Steel Rod The bench mark is located 82 feet (25 m) south of the SE corner of a private residence, 39 feet (12 m) east of the centerline of the driveway leading to the residence, and 3 feet (1 m) NNE of a power pole with a witness sign at ground level. The bench mark is 0.25 feet (0.1 m) below ground level, crimped to a copper-clad steel rod driven 24 feet (7 m) to refusal, and encased in 4-inch PVC pipe and concrete kickblock. BENCH MARK STAMPING: NO 1 1976 MONUMENTATION: Survey Disk VM#: 10219 AGENCY: PID#: BG4534 SETTING CLASSIFICATION: Copper-Clad Steel Rod The bench mark is located 46.5 feet (14.2 m) east of the NE corner of the first residence south of the tide gage site, 38.5 feet (11.7 m) west of a barbed wire fence and 21.0 feet (6.4 m) south of an enclosed concrete pad. The bench mark is at ground level, crimped to a copper-clad steel rod driven 23 feet (7 m) to refusal in the SW corner of the a 10x15 foot (3x5 m), concrete pad.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 PUBLICATION DATE: 04/06/1984 Station ID: 8729747 SUPERCEDED DATE: 04/21/2003 Name: SHIELDS POINT, BLACKWATER BAY FLORIDA NOAA Chart: 11382 Latitude: 30° 34.9' N USGS Quad: MILTON SOUTH Longitude: 87° 0.9' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: C165 RESET 1966 MONUMENTATION: Survey Disk VM#: 10221 AGENCY: PID#: BG0248 SETTING CLASSIFICATION: Concrete Post The bench mark is located near the Highway 191C overpass for Interstate 10, 28.0 feet (39.0 m), NE of the centerline of Highway 191C, 12.25 feet (37.3 m), NNE of the NW end of the NE concrete bannister of the overpass, 29.5 feet (9.0 m), ENE of a power line pole, 1.8 feet (0.5 m), SW of a metal witness post, and 1.2 feet (0.4 m), NW of the Interstate 10 right-of-way fence. The bench mark is set 1.0 foot, (0.3 m) below the ground in a concrete post. BENCH MARK STAMPING: RM NO 2 MONUMENTATION: Survey Disk VM#: 10222 AGENCY: PID#: BG3157 SETTING CLASSIFICATION: Concrete Curb The bench mark is located 12.6 feet (3.8 m) west of the centerline of the Highway 191C overpass for Interstate 10, in the SW corner of the overpass and 6 feet (2 m) NE of a witness sign. The bench mark is 0.8 foot (0.2 m) above ground level and set flush in the curb.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 PUBLICATION DATE: 04/06/1984 Station ID: 8729747 SUPERCEDED DATE: 04/21/2003 Name: SHIELDS POINT, BLACKWATER BAY FLORIDA NOAA Chart: 11382 Latitude: 30° 34.9' N USGS Quad: MILTON SOUTH Longitude: 87° 0.9' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: V 301 MONUMENTATION: Survey Disk VM#: 10223 AGENCY: PID#: BG0249 SETTING CLASSIFICATION: Concrete Railing The bench mark is located in the top of the SW concrete wingwall for the NW abutment of the State Highway 191C overpass for Interstate 10, 13.4 feet (4.1 m) SW of the centerline of State Highway 191C, 6.7 feet (2.0 m) SE of the NW end of the wingwall, and 4.5 feet (1.4 m) NW of the NW end of the SW concrete bannister. The bench mark is set 3.0 feet (0.9 m) above the level of the highway. BENCH MARK STAMPING: W 301 MONUMENTATION: Survey Disk VM#: 10224 AGENCY: PID#: BG0114 SETTING CLASSIFICATION: Concrete Railing The bench mark is located in the top of the SE end of the NE concrete wingwall for the SE abutment of the Highway 191C overpass for Interstate 10, 14.5 feet (4.4 m) NE of the centerline of the highway, and 4.7 feet (1.4 m) SE of the SE end of the NE concrete bannister. The bench mark is set 3.0 feet (0.9 m) above the level of the highway.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 PUBLICATION DATE: 04/06/1984 Station ID: 8729747 SUPERCEDED DATE: 04/21/2003 Name: SHIELDS POINT, BLACKWATER BAY FLORIDA NOAA Chart: 11382 Latitude: 30° 34.9' N USGS Quad: MILTON SOUTH Longitude: 87° 0.9' W T I D A L D A T U M S Tidal datums at SHIELDS POINT, BLACKWATER BAY based on: LENGTH OF SERIES: 10 MONTHS TIME PERIOD: APRIL 1976-MAY 1977 TIDAL EPOCH: 1960-1978 CONTROL TIDE STATION: 8729840 PENSACOLA Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET: HIGHEST OBSERVED WATER LEVEL (03/28/1977) = 2.84 MEAN HIGHER HIGH WATER MHHW = 1.55 MEAN HIGH WATER MHW = 1.47 MEAN TIDE LEVEL MTL = 0.80 * NATIONAL GEODETIC VERTICAL DATUM NGVD29 = 0.35 MEAN LOW WATER MLW = 0.12 MEAN LOWER LOW WATER MLLW = 0.00 LOWEST OBSERVED WATER LEVEL (12/21/1976) = -1.52 * NGVD reference based on adjustment of 1971 and NOS levels of 7/11/77. North American Vertical Datum (NAVD88) Bench Mark Elevation Information In FEET above: Stamping or Designation MLLW MHW NO 2 1976 15.24 13.77 NO 1 1976 16.25 14.78 C165 RESET 1966 16.50 15.03 RM NO 2 44.17 42.70 V 301 46.23 44.76 W 301 46.96 45.49
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 PUBLICATION DATE: 04/06/1984 Station ID: 8729747 SUPERCEDED DATE: 04/21/2003 Name: SHIELDS POINT, BLACKWATER BAY FLORIDA NOAA Chart: 11382 Latitude: 30° 34.9' N USGS Quad: MILTON SOUTH Longitude: 87° 0.9' 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 (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 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.