U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8658501 PUBLICATION DATE: 06/16/2004 Name: ORTON POINT, CAPE FEAR RIVER NC NOAA Chart: 11537 Latitude: 34° 3.4' N ( 34.05670) USGS Quad: CAROLINA BEACH Longitude: 77° 56.4' W ( -77.94000) To reach the tidal bench marks from Southport, proceed by boat north on the Cape Fear River for about 19.8 km (12.3 statue mi) to the forward range marker at the north end of Upper Midnight Channel Range (also near the SW end of Lower Liliput Range). The bench marks are located on a dirt levee separating the salt marsh from the rice fields of Orton Planatation, west and NW of the range marker. The tide gage and staff were located at the NW corner of the forward range marker. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 8501 A 1976 DESIGNATION: 865 8501 A TIDAL MONUMENTATION: Tidal Station disk VM#: 3586 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Unspecified steel rod OPUS PID: LATITUDE: 34° 3.4' N ( 34.05670) LONGITUDE: 77° 56.4' W ( -77.94000) The primary bench mark is a disk located on the Orton Plantation levee west of the SW end of Lower Lilput Range, in line with the NW corner of the forward range marker and a dredging range mark adjacent to the shore. The bench mark is set at ground level and crimped to the top of an unspecified steel rod driven 1.2 m (4 ft).
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 8658501 PUBLICATION DATE: 06/16/2004 Name: ORTON POINT, CAPE FEAR RIVER NC NOAA Chart: 11537 Latitude: 34° 3.4' N ( 34.05670) USGS Quad: CAROLINA BEACH Longitude: 77° 56.4' W ( -77.94000) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 8501 B 1976 DESIGNATION: 865 8501 B TIDAL MONUMENTATION: Tidal Station disk VM#: 3587 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Unspecified steel rod OPUS PID: LATITUDE: 34° 3.4' N ( 34.05670) LONGITUDE: 77° 56.4' W ( -77.94000) The bench mark is a disk located on the Orton Plantation levee, 65 m (214 ft) north of bench mark 8501 A 1976. The bench mark is set at ground level and crimped to the top of an unspecified steel rod driven 1.2 m (4 ft). BENCH MARK STAMPING: 8501 C 1976 DESIGNATION: 865 8501 C TIDAL MONUMENTATION: Tidal Station disk VM#: 3588 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Unspecified steel rod OPUS PID: LATITUDE: 34° 3.4' N ( 34.05670) LONGITUDE: 77° 56.4' W ( -77.94000) The bench mark is a disk located on the Orton Plantation Levee, 76 m (250 ft) north of bench mark 8501 B 1976. The bench mark is set at ground level and crimped to the top of an unspecified steel rod driven 1.2 m (4 ft).
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 8658501 PUBLICATION DATE: 06/16/2004 Name: ORTON POINT, CAPE FEAR RIVER NC NOAA Chart: 11537 Latitude: 34° 3.4' N ( 34.05670) USGS Quad: CAROLINA BEACH Longitude: 77° 56.4' W ( -77.94000) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 8501 D 1976 DESIGNATION: 865 8501 D TIDAL MONUMENTATION: Tidal Station disk VM#: 3589 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Unspecified steel rod OPUS PID: LATITUDE: 34° 3.4' N ( 34.05670) LONGITUDE: 77° 56.4' W ( -77.94000) The bench mark is a disk located on the Orton Plantation levee, 84 m (275 ft) north of bench mark 8501 C 1976. The bench mark is set at ground level and crimped to the top of an unspecified steel rod driven 1.2 m (4 ft). BENCH MARK STAMPING: 8501 E 1976 DESIGNATION: 865 8501 E TIDAL MONUMENTATION: Tidal Station disk VM#: 3590 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Unspecified steel rod OPUS PID: LATITUDE: 34° 3.4' N ( 34.05670) LONGITUDE: 77° 56.4' W ( -77.94000) The bench mark is a disk located on the Orton Plantation levee, 76 m (250 ft) north of bench mark 8501 D 1976. The bench mark is set at ground level and crimped to the top of an unspecified steel rod driven 1.2 m (4 ft).
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 8658501 PUBLICATION DATE: 06/16/2004 Name: ORTON POINT, CAPE FEAR RIVER NC NOAA Chart: 11537 Latitude: 34° 3.4' N ( 34.05670) USGS Quad: CAROLINA BEACH Longitude: 77° 56.4' W ( -77.94000) T I D A L D A T U M S Tidal datums at ORTON POINT, CAPE FEAR RIVER based on: LENGTH OF SERIES: 3 MONTHS TIME PERIOD: April 1976 - June 1976 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8658120 WILMINGTON, CAPE FEAR RIVER Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 1.407 MEAN HIGH WATER MHW = 1.317 MEAN SEA LEVEL MSL = 0.699 MEAN TIDE LEVEL MTL = 0.682 MEAN LOW WATER MLW = 0.047 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 8501 A 1976 2.683 1.366 8501 B 1976 2.898 1.581 8501 C 1976 3.099 1.782 8501 D 1976 2.607 1.290 8501 E 1976 2.688 1.371
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8658501 PUBLICATION DATE: 06/16/2004 Name: ORTON POINT, CAPE FEAR RIVER NC NOAA Chart: 11537 Latitude: 34° 3.4' N ( 34.05670) USGS Quad: CAROLINA BEACH Longitude: 77° 56.4' W ( -77.94000) 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.