U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 4 Station ID: 8732828 PUBLICATION DATE: 01/24/2018 Name: WEEKS BAY, MOBILE BAY AL NOAA Chart: 11376 Latitude: 30° 25.0' N ( 30.41689) USGS Quad: MOBILE Longitude: 87° 49.5' W ( -87.82539) From Interstate 10 South in Mobile proceed south on I-10 to Highway 98 South. Travel south on 98 South for 28 miles to the Weeks Bay Reserve and the Fish River Bridge, before going over the bridge take a paved road on the left and follow it until it crosses under the bridge. Before you go under the bridge there is a dirt path that turns left, take that path and the station is located on the left next to the canal. The bench marks are located along the bridge. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 2828 A 2007 DESIGNATION: 873 2828 A MONUMENTATION: Tidal Station disk VM#: 18487 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless steel rod OPUS PID#: BBBG65 LATITUDE: 30° 25.0' N ( 30.41678) LONGITUDE: 87° 49.5' W ( -87.82542) The primary bench mark is a disk located at the Weeks Bay Reserve on the north side of Highway 98 Bridge over the Fish River 20.11 m (65.98 ft) NE of the centerline of a paved road leading to the Weeks Bay Boat Ramp, 5.45 m (17.88 ft) south of the southern corner of the NOAA Tide Station, 1.49 m (4.89 ft) WNW of a witness post. The bench mark is set flush with the ground being a deep rod driven 27.4 m (89.89 ft) to refusal with grease sleeve and an aluminum logo cap stamped 2828 A 2007.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 4 Station ID: 8732828 PUBLICATION DATE: 01/24/2018 Name: WEEKS BAY, MOBILE BAY AL NOAA Chart: 11376 Latitude: 30° 25.0' N ( 30.41689) USGS Quad: MOBILE Longitude: 87° 49.5' W ( -87.82539) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 2828 B 2007 DESIGNATION: 873 2828 B MONUMENTATION: Tidal Station disk VM#: 18489 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 30° 25.1' N ( 30.41767) LONGITUDE: 87° 49.6' W ( -87.82703) The bench mark is a vertical mark set flush in the fifth bridge support from the West end of the bridge on the South side, 300.0 ft (91.4 m) South of the wing wall on the North end of the us 98 bridge, 244.0 ft (74.4 m) North of the center line of the service road leading into the weeks bay public boat ramp, 39.5 ft (12.0 m) East of the center line of the north to suth asphalt bike path, 26.6 ft (8.1 m) West of the center line of the pile bent, 4.3 ft (1.3 m) above ground under pile bent. BENCH MARK STAMPING: 2828 C 2007 DESIGNATION: 873 2828 C MONUMENTATION: Survey disk VM#: 18490 AGENCY: National Ocean Service (NOS) IDB PID#: SETTING CLASSIFICATION: Concrete wingwall OPUS PID: LATITUDE: 30° 25.0' N ( 30.41739) LONGITUDE: 87° 49.6' W ( -87.82686) The bench mark is a disk set flush with the concrete wingwall, located at the Highway 98 Bridge over the Fish River on the SW end of the bridge, 44.79 m (146.95 ft) SE of mile marker 56, 11.55 m (37.89 ft) NE of the old Highway 98 roadway, 7.14 m (23.43 ft) south of the centerline of Highway 98 Bridge, and 0.54 m (1.77 ft) above ground.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 4 Station ID: 8732828 PUBLICATION DATE: 01/24/2018 Name: WEEKS BAY, MOBILE BAY AL NOAA Chart: 11376 Latitude: 30° 25.0' N ( 30.41689) USGS Quad: MOBILE Longitude: 87° 49.5' W ( -87.82539) T I D A L D A T U M S Tidal datums at WEEKS BAY, MOBILE BAY based on: LENGTH OF SERIES: 6 YEARS TIME PERIOD: 3/08-2/12, 1/14-12/14, 5/15-4/16 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8729840 PENSACOLA, PENSACOLA BAY Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: HIGHEST OBSERVED WATER LEVEL (10/08/2017) = 1.765 MEAN HIGHER HIGH WATER MHHW = 0.490 MEAN HIGH WATER MHW = 0.455 MEAN TIDE LEVEL MTL = 0.245 MEAN SEA LEVEL MSL = 0.243 MEAN LOW WATER MLW = 0.034 MEAN LOWER LOW WATER MLLW = 0.000 LOWEST OBSERVED WATER LEVEL (02/05/2009) = -0.556 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 2828 A 2007 0.786 0.331 2828 B 2007 2.769 2.314 2828 C 2007 3.509 3.054
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 4 Station ID: 8732828 PUBLICATION DATE: 01/24/2018 Name: WEEKS BAY, MOBILE BAY AL NOAA Chart: 11376 Latitude: 30° 25.0' N ( 30.41689) USGS Quad: MOBILE Longitude: 87° 49.5' W ( -87.82539) 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.