U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 6 Station ID: 8729152 PUBLICATION DATE: 10/30/2003 Name: ALLIGATOR BAYOU, PANAMA CITY FL NOAA Chart: 11391 Latitude: 30° 10.2' N ( 30.17000) USGS Quad: PANAMA CITY BEACH Longitude: 85° 45.3' W ( -85.75500) To reach the tidal bench marks from the west end of the Hathaway Bridge of St. Andrews Bay, go west on U.S. Highway 98 for 1.3 km (0.8 mi) to Thomas Drive, turn left and go south on Thomas Drive for 1.6 km (1.0 mi) to a paved road on the left which is the west gate entrance to the Naval Coastal System Center (Crag Road), turn left and go east (passing through the gate for 0.08 km (0.05 mi) to a security station (building No 329), then proceed north 0.08 km (0.05 mi) to a U-turn, turn right and go south for 0.6 km (0.4 mi) on Crag Road to a T-junction, turn left and go east for 0.3 km (0.2 mi) to the Coast Guard Station Boat Slip. The bench marks are located along the pier. The tide gage and staff were on the north edge of the pier, just west of where the Coast Guard docks their smaller boats and east of their boat launching ramp. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 9152 B 1991 DESIGNATION: 872 9152 B TIDAL MONUMENTATION: Flange-encased Rod VM#: 12497 AGENCY: National Ocean Service (NOS) IDB PID#: AI3223 SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 30° 10.2' N ( 30.17000) LONGITUDE: 85° 45.4' W ( -85.75670) The primary bench mark is a flange encased rod set 0.2 km (0.1 mile) south of the T-junction on Crag Road, 14.39 m (47.2 ft) north of the centerline of Crag Road, 11.13 m (36.5 ft) south of the concrete brick Coast Guard Station, 9.14 m (30.0 ft) NE of a power pole, and 0.24 m (0.8 ft) south of a Carsonite witness post. The bench mark is the top of a stainless steel rod driven to a depth of 24.4 m (80 ft), and encased in a 5-inch PVC pipe with logo cap and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 6 Station ID: 8729152 PUBLICATION DATE: 10/30/2003 Name: ALLIGATOR BAYOU, PANAMA CITY FL NOAA Chart: 11391 Latitude: 30° 10.2' N ( 30.17000) USGS Quad: PANAMA CITY BEACH Longitude: 85° 45.3' W ( -85.75500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 9152 A 1991 DESIGNATION: 872 9152 A TIDAL MONUMENTATION: Tidal Station disk VM#: 12499 AGENCY: National Ocean Service (NOS) IDB PID#: AI3221 SETTING CLASSIFICATION: Concrete pier OPUS PID: LATITUDE: 30° 10.2' N ( 30.17000) LONGITUDE: 85° 45.3' W ( -85.75500) The bench mark is a disk set flush in the top of a concrete pier, at the SW corner of the westernmost covered boat slip, 75.44 m (247.5 ft) north of the centerline of Crag Road, 54.44 m (178.6 ft) NW of the NW corner of a brick building (U.S. Coast Guard Old Building), 2.41 m (7.9 ft) east of the west edge of a 15 m (50 ft) long concrete pier at a boat slip, and 2.41 m (7.9 ft) east of the east edge of the easternmost boat launching ramp. BENCH MARK STAMPING: 9152 C 1991 DESIGNATION: 872 9152 C TIDAL MONUMENTATION: Tidal Station disk VM#: 12500 AGENCY: National Ocean Service (NOS) IDB PID#: AI3224 SETTING CLASSIFICATION: Concrete monument OPUS PID#: AI3224 LATITUDE: 30° 10.2' N ( 30.17000) LONGITUDE: 85° 45.5' W ( -85.75830) The bench mark is a disk set flush in the top of a concrete monument about 0.5 km (0.3 mile) south on Thomas Drive from the entrance to the Naval Coastal System Center, 15 m (50 ft) east of the centerline of Thomas Drive, 3 m (10 ft) NE of power pole #60240-42753, 0.61 m (2.0 ft) SW of a 2 m (6 ft) chain link fence, and 0.46 m (1.5 ft) SW of a Carsonite witness post.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 6 Station ID: 8729152 PUBLICATION DATE: 10/30/2003 Name: ALLIGATOR BAYOU, PANAMA CITY FL NOAA Chart: 11391 Latitude: 30° 10.2' N ( 30.17000) USGS Quad: PANAMA CITY BEACH Longitude: 85° 45.3' W ( -85.75500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 9152 D 1991 DESIGNATION: 872 9152 D TIDAL MONUMENTATION: Flange-encased Rod VM#: 12501 AGENCY: National Ocean Service (NOS) IDB PID#: AI3225 SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 30° 10.0' N ( 30.16670) LONGITUDE: 85° 45.4' W ( -85.75670) The bench mark is a flange encased rod set in a grassy area north of the parking lot of the Jr. Food Store, 2.4 km (1.5 miles) south on Thomas Drive from its junction with U.S. Highway 98, 22.22 m (72.9 ft) west of the centeline of Thomas Drive, 11.37 m (37.3 ft) ENE of the NE corner of a brick building (Jr. Food Store), 0.85 m (2.8 ft) east of a 0.61 m x 0.61 m (2 ft x 2 ft) concrete base for a light pole, and 0.82 m (2.7 ft) east of a Carsonite witness post. The bench mark is the top of a stainless steel rod driven to a depth of 24.4 m (80.0 ft), and encased in a 5-inch PVC pipe with logo cap and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 6 Station ID: 8729152 PUBLICATION DATE: 10/30/2003 Name: ALLIGATOR BAYOU, PANAMA CITY FL NOAA Chart: 11391 Latitude: 30° 10.2' N ( 30.17000) USGS Quad: PANAMA CITY BEACH Longitude: 85° 45.3' W ( -85.75500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: NCSC NO 3 1989 DESIGNATION: NCSC NO 3 MONUMENTATION: Survey disk VM#: 12502 AGENCY: US Army Corps of Engineers (USE) IDB PID#: AI3222 SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 30° 10.2' N ( 30.17000) LONGITUDE: 85° 45.4' W ( -85.75670) The bench mark is a disk set in top of a concrete monument NW of the NW corner of the U.S. Coast Guard main building, near the edge of Alligator Bayou, 62.18 m (204.0 ft) north of the centerline of Crag Road, 22.92 m (75.2 ft) NW of a concrete brick building, 14.94 m (49.0 ft) NW of a 4 m (12 ft) satellite dish, 5.49 m (18.0 ft) south of the approximate shoreline, and 0.76 m (2.5 ft) north of a carsonite witness post.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 6 Station ID: 8729152 PUBLICATION DATE: 10/30/2003 Name: ALLIGATOR BAYOU, PANAMA CITY FL NOAA Chart: 11391 Latitude: 30° 10.2' N ( 30.17000) USGS Quad: PANAMA CITY BEACH Longitude: 85° 45.3' W ( -85.75500) T I D A L D A T U M S Tidal datums at ALLIGATOR BAYOU, PANAMA CITY based on: LENGTH OF SERIES: 2 MONTHS TIME PERIOD: September 1991 - October 1991 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8729108 PANAMA CITY, ST. ANDREW BAY Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 0.417 MEAN HIGH WATER MHW = 0.398 MEAN SEA LEVEL MSL = 0.210 MEAN TIDE LEVEL MTL = 0.207 North American Vertical Datum NAVD88 = 0.159 MEAN LOW WATER MLW = 0.016 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 9152 B 1991 5.340 4.942 9152 A 1991 1.163 0.765 9152 C 1991 3.653 3.255 9152 D 1991 5.013 4.615 NCSC NO 3 1989 2.663 2.265
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 6 Station ID: 8729152 PUBLICATION DATE: 10/30/2003 Name: ALLIGATOR BAYOU, PANAMA CITY FL NOAA Chart: 11391 Latitude: 30° 10.2' N ( 30.17000) USGS Quad: PANAMA CITY BEACH Longitude: 85° 45.3' W ( -85.75500) 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.