U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8730667 PUBLICATION DATE: 06/13/2003 Name: ALABAMA POINT, PERDIDO PASS AL NOAA Chart: 11382 Latitude: 30° 16.7' N ( 30.27830) USGS Quad: FOLEY Longitude: 87° 33.3' W ( -87.55500) To reach the bench marks from the intersection of State Highways 292 and 182, proceed south on State Highway 182 to the Alabama State line on the beach road (AKA Perdido Key Drive), then continue west for 3.7 km (2.3 mi) over the Perdido Pass bridge, then turn right on the west side of the bridge and continue east parallel to the bridge to the Alabama Marine Police headquarters located at Perdido Pass. The bench marks are located on State property between the headquarters and west side of Perdido Pass bridge. The gauge and staff were located on the pier just west of the west end of the sea wall. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 0667 A 1993 DESIGNATION: 873 0667 A MONUMENTATION: Tidal Station disk VM#: 12716 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete sea wall OPUS PID: LATITUDE: 30° 16.7' N ( 30.27831) LONGITUDE: 87° 33.3' W ( -87.55500) The primary bench mark is a disk set in a concrete sea wall at the Alabama Marine Police station, 15.45 m (50.7 ft) west of the NW corner of a concrete block fuel drum, 5.27 m (17.3 ft) east of the wooden pier, and 0.3 m (1 ft) south of the north edge of the sea wall.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 8730667 PUBLICATION DATE: 06/13/2003 Name: ALABAMA POINT, PERDIDO PASS AL NOAA Chart: 11382 Latitude: 30° 16.7' N ( 30.27830) USGS Quad: FOLEY Longitude: 87° 33.3' W ( -87.55500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 0667 B 1993 DESIGNATION: 873 0667 B MONUMENTATION: Tidal Station disk VM#: 12717 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete sea wall OPUS PID: LATITUDE: 30° 16.7' N ( 30.27833) LONGITUDE: 87° 33.3' W ( -87.55500) The bench mark is a disk set in a concrete sea wall at the Alabama Marine Police station, 25.54 m (83.8 ft) north of the NE corner of a concrete helicopter pad, 4.45 m (14.6 ft) east of an anchored chain link fence, and 0.6 m (2 ft) south of the north edge of the sea wall. BENCH MARK STAMPING: 0667 C 1993 DESIGNATION: 873 0667 C MONUMENTATION: Tidal Station disk VM#: 12718 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete sea wall OPUS PID: LATITUDE: 30° 16.7' N ( 30.27830) LONGITUDE: 87° 33.3' W ( -87.55500) The bench mark is a disk set in a concrete sea wall at the Alabama Marine Police station, 37.58 m (123.3 ft) north of the centerline of Perdido Pass bridge measured from underneath the bridge, 33.04 m (108.4 ft) east of the SE corner of a concrete helicopter pad, and 0.67 m (2.2 ft) west of the east edge of the sea wall.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 8730667 PUBLICATION DATE: 06/13/2003 Name: ALABAMA POINT, PERDIDO PASS AL NOAA Chart: 11382 Latitude: 30° 16.7' N ( 30.27830) USGS Quad: FOLEY Longitude: 87° 33.3' W ( -87.55500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 0667 D 1993 DESIGNATION: 873 0667 D MONUMENTATION: Tidal Station disk VM#: 12719 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete pad OPUS PID: LATITUDE: 30° 16.7' N ( 30.27830) LONGITUDE: 87° 33.3' W ( -87.55500) The bench mark is a disk set in a concrete helicopter pad at the Alabama Marine Police station, 29.90 m (98.1 ft) north of the second bridge support east of the west end of the bridge, 12.22 m (40.1 ft) SE of the NW corner of the pad, and 8.53 m (28.0 ft) east of the SW corner of the pad. BENCH MARK STAMPING: 0667 E 1993 DESIGNATION: 873 0667 E MONUMENTATION: Tidal Station disk VM#: 12720 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete porch OPUS PID: LATITUDE: 30° 16.7' N ( 30.27830) LONGITUDE: 87° 33.3' W ( -87.55500) The bench mark is a disk set in a concrete porch at the Alabama Marine Police station, 5.39 m (17.7 ft) SW of the entrance to the Alabama Marine Police headquarters, 2.10 m (6.9 ft) south of the SW corner of the headquarters, and 0.76 m (2.5 ft) NW of the Alabama Marine Police sign.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 8730667 PUBLICATION DATE: 06/13/2003 Name: ALABAMA POINT, PERDIDO PASS AL NOAA Chart: 11382 Latitude: 30° 16.7' N ( 30.27830) USGS Quad: FOLEY Longitude: 87° 33.3' W ( -87.55500) T I D A L D A T U M S Tidal datums at ALABAMA POINT, PERDIDO PASS based on: LENGTH OF SERIES: 4 MONTHS TIME PERIOD: December 1993 - March 1994 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8729840 PENSACOLA, PENSACOLA BAY Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 0.262 MEAN HIGH WATER MHW = 0.250 MEAN TIDE LEVEL MTL = 0.129 MEAN SEA LEVEL MSL = 0.126 MEAN LOW WATER MLW = 0.007 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 0667 A 1993 1.459 1.209 0667 B 1993 1.461 1.211 0667 C 1993 1.470 1.220 0667 D 1993 3.401 3.151 0667 E 1993 3.021 2.771
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8730667 PUBLICATION DATE: 06/13/2003 Name: ALABAMA POINT, PERDIDO PASS AL NOAA Chart: 11382 Latitude: 30° 16.7' N ( 30.27830) USGS Quad: FOLEY Longitude: 87° 33.3' W ( -87.55500) 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.