U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 7 Station ID: 8655353 PUBLICATION DATE: 01/29/2013 Name: PORTSMOUTH NC NOAA Chart: 11550 Latitude: 34° 58.8' N ( 34.97939) USGS Quad: WAINWRIGHT ISLAND Longitude: 76° 9.8' W ( -76.16308) To reach the tidal bench marks with a 4 wheel drive vehicle from the intersection of Highway 12 and Highway 70 near Sealevel, North Carolina, proceed southeast then east on Hwy 70 (Seashore Drive) for 7.2 km (4.5 mi) to School Drive, turn left onto School Drive and proceed northwest for 0.4 km (0.2 mi) to its intersection with Shell Road, turn right on Shell Road and proceed northeast for 1.0 km (0.6 mi) to its intersection with Core Sound Loop Road and Morris Marina Road, proceed straight onto Morris Marina road continuing NE for 1.3 km (0.8 mi) to its termination at the Morris Marina parking lot. Board the ferry and continue east 6.1 km (3.8 mi) or 45 minutes to the ferry landing area at the National Park Service Long Point cabin area on Portsmouth Island, disembark the ferry and continue southeast on sand road for 0.2 km (0.1 mi) to beach ramp number 16, turn left and proceed northeast on the beach for 12.9 km (8.0 mi) to beach ramp number 9, turn left and proceed north-northwest on sand track for 0.3 km (0.2 mi) to its termination and a cul-de-sac. The bench marks are located along the sand track and across the slough to the northwest. The tide gauge is located across the slough to the northwest. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 5353 C 2012 DESIGNATION: 865 5353 C MONUMENTATION: Metal Rod VM#: 20418 AGENCY: NOS IDB PID#: SETTING CLASSIFICATION: Flange-encased rod OPUS PID: LATITUDE: 34° 58.7' N ( 34.97914) LONGITUDE: 76° 9.8' W ( -76.16325) The primary bench mark is a flange-encased rod located along the eastern edge of junipers west of the slough, 27.60 m (90.6 ft) northeast of the base of a large cedar tree, 24.10 m (79.1 ft) southwest of the edge of the slough bank, 1.12 m (3.7 ft) northeast of an orange carsonite NOS witness post and 0.68 m (2.2 ft) west-southwest of a pressure treated 4x4 wooden post projecting 0.33 m (1.1 ft) above grade. The datum point is set 13 cm (5 inches) below grade, being the top of a stainless steel rod driven 24.4 m (80.1 ft) to refusal, in a sleeve extending to a depth of 0.9 m (3.0 ft) and encased in a 5-inch (13 cm) National Geodetic Survey logo cap with concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 7 Station ID: 8655353 PUBLICATION DATE: 01/29/2013 Name: PORTSMOUTH NC NOAA Chart: 11550 Latitude: 34° 58.8' N ( 34.97939) USGS Quad: WAINWRIGHT ISLAND Longitude: 76° 9.8' W ( -76.16308) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 5353 B 2012 DESIGNATION: 865 5353 B MONUMENTATION: Metal Rod VM#: 20419 AGENCY: NOS IDB PID#: SETTING CLASSIFICATION: Flange-encased rod OPUS PID#: BBCS62 LATITUDE: 34° 58.7' N ( 34.97850) LONGITUDE: 76° 9.7' W ( -76.16136) The bench mark is a flange-encased rod located in juniper bushes north of a sand parking area, 21.62 m (70.9 ft) east-northeast of the east bank of the slough, 8.02 m (26.3 ft) north of the center of the parking area, 4.35 m (14.3 ft) east-northeast of the prolongation of the centerline of the access road from the beach, 1.13 m (3.7 ft) south-southwest of an orange carsonite NOS witness post and 1.12 m (3.7 ft) south of a wooden post and sign with the letter p for parking. The datum point is set 10 cm (4 inches) below grade, being the top of a stainless steel rod driven 23.1 m (75.8 ft) to refusal, in a sleeve extending to a depth of 0.9 m (3.0 ft) and encased in a 5-inch (13 cm) National Ocean Service logo cap with concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 7 Station ID: 8655353 PUBLICATION DATE: 01/29/2013 Name: PORTSMOUTH NC NOAA Chart: 11550 Latitude: 34° 58.8' N ( 34.97939) USGS Quad: WAINWRIGHT ISLAND Longitude: 76° 9.8' W ( -76.16308) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 5353 A 2012 DESIGNATION: 865 5353 A MONUMENTATION: Metal Rod VM#: 20420 AGENCY: NOS IDB PID#: SETTING CLASSIFICATION: Flange-encased rod OPUS PID#: BBCS61 LATITUDE: 34° 58.5' N ( 34.97556) LONGITUDE: 76° 9.7' W ( -76.16131) The bench mark is a flange-encased rod located in a cluster of juniper bushes on the north side of a sand jeep trail, 86.93 m (285.2 ft) north-northeast of a sign with a graphic of a crossed-out jeep, 79.90 m (262.1 ft) west-southwest of a sign with a graphic of a jeep, 29.72 m (97.5 ft) west-northwest of a sign with a graphic of a jeep, 27.05 m (88.7 ft) north-northwest of the centerline of the sand jeep trail, 11.61 m (38.1 ft) north-northwest of an orange carsonite NOS witness post and 0.78 m (2.6 ft) north-northwest of a second orange carsonite NOS witness post. The datum point is set 11 cm (4 inches) below grade, being the top of a stainless steel rod driven 23.1 m (75.8 ft) to refusal, in a sleeve extending to a depth of 0.9 m (3.0 ft) and encased in a 5-inch (13 cm) National Geodetic Survey logo cap with concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 7 Station ID: 8655353 PUBLICATION DATE: 01/29/2013 Name: PORTSMOUTH NC NOAA Chart: 11550 Latitude: 34° 58.8' N ( 34.97939) USGS Quad: WAINWRIGHT ISLAND Longitude: 76° 9.8' W ( -76.16308) T I D A L B E N C H M A R K S BENCH MARK STAMPING: CALO 02 2010 DESIGNATION: CALO 02 2010 MONUMENTATION: Metal Rod VM#: 20421 AGENCY: National Park Service IDB PID#: SETTING CLASSIFICATION: OPUS PID: LATITUDE: 34° 58.4' N ( 34.97327) LONGITUDE: 76° 9.8' W ( -76.16402) To reach from the National Park Service long point ferry landing proceed southeast on dirt road to long point camp east for 0.06 mi (0.1 km) to fork in sand road known as back road. Take left fork of back road and proceed north for 7.01 mi (11.3 km) to beach access ramp 10A. Continue north along back road north for 0.35 mi (0.6 km) to the station set flush with the ground. The station is also south 0.32 mi (0.5 km) along back road from beach access ramp 9. Located 55.30 ft (16.9 m) northwest of the centerline of back road, 43.32 ft (13.2 m) south of another 4 inch (10 cm) treated wooden post with a NCGS reference tag, 3.09 ft (0.9 m) south of a 4 inch (10 cm) treated wooden post with NCGS reference tag, treated wooden posts are in line to the north of station. Note - Magnetic properties are a bolt set on north side of monument.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 7 Station ID: 8655353 PUBLICATION DATE: 01/29/2013 Name: PORTSMOUTH NC NOAA Chart: 11550 Latitude: 34° 58.8' N ( 34.97939) USGS Quad: WAINWRIGHT ISLAND Longitude: 76° 9.8' W ( -76.16308) T I D A L B E N C H M A R K S BENCH MARK STAMPING: USE DESIGNATION: USE MONUMENTATION: Survey disk VM#: 20422 AGENCY: IDB PID#: SETTING CLASSIFICATION: OPUS PID: LATITUDE: 34° 58.7' N ( 34.97881) LONGITUDE: 76° 9.8' W ( -76.16371) The bench mark is a disk set on top of a 0.20 m (0.7 ft) x 0.19 m (0.6 ft) concrete block surrounded by dense juniper bushes, 12.12 m (39.8 ft) southeast of bench mark swash no 1, 1.3 m (4.3 ft) west-southwest of a fallen cypress tree and 0.15 m (0.5 ft) southwest from an orange carsonite National Ocean Service witness post. Described by Coast and Geodetic Survey 1960.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 7 Station ID: 8655353 PUBLICATION DATE: 01/29/2013 Name: PORTSMOUTH NC NOAA Chart: 11550 Latitude: 34° 58.8' N ( 34.97939) USGS Quad: WAINWRIGHT ISLAND Longitude: 76° 9.8' W ( -76.16308) T I D A L D A T U M S Tidal datums at PORTSMOUTH based on: LENGTH OF SERIES: 3 MONTHS TIME PERIOD: May 2012 - July 2012 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8654467 USCG STATION HATTERAS, PAMLICO SOUND Elevations of tidal datums referred to Mean Sea Level (MSL), in METERS: MEAN SEA LEVEL MSL = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MSL 5353 C 2012 0.641 5353 B 2012 0.412 5353 A 2012 1.830 CALO 02 2010 1.409 USE 0.816 Foot Notes: This station has been determined to be Non-tidal for tidal datum purposes. There is either no measureable periodic rise and fall of the tide at this location, or it may be present but inconsistent, or the periodic tide is present and consistent, however the Mean Range of Tide (MN) is negligible, that is below the established tidal/non-tidal threshold of 0.03m (0.10ft). Only the datum of local Mean Sea Level (MSL) is published at these stations. For Nautical Charting Datum applications, a non-tidal Low Water Datum (LWD) is established as 0.50ft (0.15m) below MSL.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 7 of 7 Station ID: 8655353 PUBLICATION DATE: 01/29/2013 Name: PORTSMOUTH NC NOAA Chart: 11550 Latitude: 34° 58.8' N ( 34.97939) USGS Quad: WAINWRIGHT ISLAND Longitude: 76° 9.8' W ( -76.16308) 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.