U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 Station ID: 8675761 PUBLICATION DATE: 07/25/2012 Name: DAYMARK #185, ROCKDEDUNDY R ENT GA NOAA Chart: 11510 Latitude: 31° 22.4' N ( 31.37386) USGS Quad: ALTAMAHA SOUND Longitude: 81° 20.0' W ( -81.33394) From the boat ramp at Skippers Fish Camp located on the NW side of the HWY. 17/25 bridge over the Darien River proceed 14.2 km (8.82 mi) east on the Darien River to the ICW at Daymark #184, proceed 1.1 km (6.8 mi) south to Daymark #185. The benchmarks are onshore just east of Daymark #185. The tide gauge is on the Daymark #185. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 5761 A 1980 DESIGNATION: 867 5761 A 1980 MONUMENTATION: Survey disk VM#: 4896 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Unspecified deep rod OPUS PID: LATITUDE: 31° 22.4' N ( 31.37375) LONGITUDE: 81° 20.0' W ( -81.33347) The primary bench mark is located from the boat ramp at Skippers Fish Camp located on the northwest side of the highway 17/25 bridge over the Darien River proceed 14.2 km (8.8 mi) east on the Darien river to the ICWW at Daymark Number 184, proceed 1.1 km (0.7 mi) south to Daymark Number 185, 47.5 m (155.8 ft) southeast of NOAA/NOS tide station 867 5761, 23.8 m (78.1 ft) southwest of bench mark USACE, 8.1 m (26.6 ft) east of shoreline. The datum point is a disk set 0.3 m (1.0 ft) above ground, crimped to a stainless steel rod driven to refusal and encased in a 4-inch PVC pipe.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 Station ID: 8675761 PUBLICATION DATE: 07/25/2012 Name: DAYMARK #185, ROCKDEDUNDY R ENT GA NOAA Chart: 11510 Latitude: 31° 22.4' N ( 31.37386) USGS Quad: ALTAMAHA SOUND Longitude: 81° 20.0' W ( -81.33394) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 2 DESIGNATION: 867 5761 2 MONUMENTATION: Rivet VM#: 4894 AGENCY: Corps of Engineers IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 31° 22.4' N ( 31.37392) LONGITUDE: 81° 20.0' W ( -81.33303) The bench mark is a monel rivet located from the boat ramp at Skippers Fish Camp located on the northwest side of the highway 17/25 bridge over the Darien River proceed 14.2 km (8.8 mi) east on the Darien River to the ICWW at Daymark Number 184, proceed 1.1 km (0.7 mi) south to Daymark Number 185, 60.8 m (199.5 ft) east of NOAA/NOS tide station 867 5761, 19.2 m (63.0 ft) northeast of bench mark USACE 1, 15.2 m (49.9 ft) southwest of bench mark MONEL RIVET no stamping. The bench mark is a MONEL RIVET set on top of a concrete monument 0.6 m (2.0 ft) above ground. BENCH MARK STAMPING: NO 1 1949 DESIGNATION: 867 5761 TIDAL 1 MONUMENTATION: Survey disk VM#: 4895 AGENCY: Corps of Engineers IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 31° 22.4' N ( 31.37392) LONGITUDE: 81° 20.0' W ( -81.33325) The bench mark is located from the boat ramp at Skippers Fish Camp located on the northwest side of the highway 17/25 bridge over the Darien River proceed 14.2 km (8.8 mi) east on the Darien River to the ICWW at Daymark Number 184, proceed 1.1 km (0.7 mi) south to Daymark Number 185, 54.5 m (178.8 ft) east of NOAA/NOS tide station 867 5761, 23.8 m (78.1 ft) northeast of bench mark 5761 A, 19.2 m (63.0 ft) southwest of bench mark MONEL RIVET 2, 10.7 m (35.1 ft) east of shoreline. The bench mark is a disk set on top of a concrete monument 0.3 m (1.0 ft) above the ground.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 Station ID: 8675761 PUBLICATION DATE: 07/25/2012 Name: DAYMARK #185, ROCKDEDUNDY R ENT GA NOAA Chart: 11510 Latitude: 31° 22.4' N ( 31.37386) USGS Quad: ALTAMAHA SOUND Longitude: 81° 20.0' W ( -81.33394) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 5761 B 1980 DESIGNATION: 867 5761 B 1980 MONUMENTATION: Survey disk VM#: 4897 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Unspecified deep rod OPUS PID#: BBCR74 LATITUDE: 31° 22.4' N ( 31.37331) LONGITUDE: 81° 20.1' W ( -81.33500) The bench mark is a disk located from the boat ramp at Skippers Fish Camp located on the northwest side of the highway 17/25 bridge over the Darien River proceed 14.2 km (8.8 mi) east on the Darien River to the ICWW at Daymark Number 184, proceed 1.1 km (0.7 mi) south to Daymark Number 185, 19.2 m (63.0 ft) east-northeast of bench mark MONEL RIVET no stamping, 1.5 m (4.9 ft) north of the west edge of a Cedar hammock. The bench mark is set 0.3 m (1.0 ft) above ground, crimped to a stainless steel rod driven to refusal and encased in a 4-inch PVC pipe. BENCH MARK STAMPING: DESIGNATION: 867 5761 NO STAMPING MONUMENTATION: Rivet VM#: 4898 AGENCY: Corps of Engineers IDB PID#: SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 31° 22.4' N ( 31.37392) LONGITUDE: 81° 20.0' W ( -81.33283) The bench mark is a MONEL RIVET located from the boat ramp at Skippers Fish Camp located on the northwest side of the highway 17/25 bridge over the Darien River proceed 14.2 km (8.8 mi) east on the Darien River to the ICWW at Daymark Number 184, proceed 1.1 km (0.7 mi) south to Daymark number 185, 19.2 m (63.0 ft) west-southwest of bench mark 5761 B, 15.2 m (49.9 ft) east-northeast of bench mark MONEL RIVET 2, 13.7 m (44.9 ft) west of the west edge of a Cedar hammock. The bench mark is a MONEL RIVET set on top of a concrete monument 0.6 m (2.0 ft) above ground.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 Station ID: 8675761 PUBLICATION DATE: 07/25/2012 Name: DAYMARK #185, ROCKDEDUNDY R ENT GA NOAA Chart: 11510 Latitude: 31° 22.4' N ( 31.37386) USGS Quad: ALTAMAHA SOUND Longitude: 81° 20.0' W ( -81.33394) T I D A L D A T U M S Tidal datums at DAYMARK #185, ROCKDEDUNDY R ENT based on: LENGTH OF SERIES: 3 MONTHS TIME PERIOD: February 2012 - April 2012 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8670870 FORT PULASKI, SAVANNAH RIVER Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 2.291 MEAN HIGH WATER MHW = 2.179 MEAN SEA LEVEL MSL = 1.170 MEAN TIDE LEVEL MTL = 1.123 MEAN LOW WATER MLW = 0.066 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 5761 A 1980 2.252 0.073 2 2.587 0.408 NO 1 1949 2.208 0.029 5761 B 1980 2.681 0.502 867 5761 NO STAMPING 2.768 0.589
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 Station ID: 8675761 PUBLICATION DATE: 07/25/2012 Name: DAYMARK #185, ROCKDEDUNDY R ENT GA NOAA Chart: 11510 Latitude: 31° 22.4' N ( 31.37386) USGS Quad: ALTAMAHA SOUND Longitude: 81° 20.0' W ( -81.33394) 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.