U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 7 Station ID: 8725943 PUBLICATION DATE: 06/03/2011 Name: BLACKBURN POINT FL NOAA Chart: 11424 Latitude: 27° 10.7' N ( 27.17830) USGS Quad: LAUREL Longitude: 82° 29.7' W ( -82.49500) To reach the tidal bench marks from the intersection of Laurel Street and U.S. Highway 41 in Laurel, proceed north on U.S. Highway 41 for 5.3 km (3.3 miles) to the intersection of State Road 789, then 1.1 km (0.7 mi) west on State Road 789 to Blackburn Point bridge over the Intracoastal Waterway. The bench marks are along State Road 7689 and the vicinity of the bridge. The tide gage and staff were located at the bridge. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 1 1973 DESIGNATION: 872 5943 1 MONUMENTATION: Tidal Station disk VM#: 10604 AGENCY: National Ocean Survey (NOS) IDB PID#: AG7167 SETTING CLASSIFICATION: Bridge abutment OPUS PID: LATITUDE: 27° 10.8' N ( 27.18000) LONGITUDE: 82° 29.7' W ( -82.49500) The primary bench mark is a disk set flush in the top of a 1.52 m (5.0 ft) square NW abutment, 0.20 m (0.66 ft) from the north side of the abutment, 0.41 m (1.33 ft) from the west side of abutment, 0.91 m (3.0 ft) east of the wood piling retaining wall, 0.61 m (2.0 ft) north of the north side of the bridge, and 0.91 m (3.0 ft) below bridge deck.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 7 Station ID: 8725943 PUBLICATION DATE: 06/03/2011 Name: BLACKBURN POINT FL NOAA Chart: 11424 Latitude: 27° 10.7' N ( 27.17830) USGS Quad: LAUREL Longitude: 82° 29.7' W ( -82.49500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 5943 H 1983 DESIGNATION: 872 5943 H MONUMENTATION: Tidal Station disk VM#: 17181 AGENCY: National Ocean Service (NOS) IDB PID#: AG7745 SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 27° 10.8' N ( 27.18000) LONGITUDE: 82° 29.9' W ( -82.49830) The bench mark is set in the top of a concrete monument, 0.3 km (0.2 mi) west of the bridge over the Intracoastal Waterway located at the junction of Blackburn Point Road and Casey Key Road, 19.51 m (64.0 ft) NW of the junction of a private drive and Blackburn Point Road, 15.09 m (49.5 ft) north of and across the road from powerline pole #200-21, 12.62 m (41.4 ft) east of the centerline of Casey Key Road, 5.64 m (18.5 ft) north of the centerline of Blackburn Point Road, 15.09 m (49.5 ft) north of and across the road from powerline pole #200-21, 0.61 m (2.0 ft) south of a witness post, and 0.09 m (0.3 ft) below ground level.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 7 Station ID: 8725943 PUBLICATION DATE: 06/03/2011 Name: BLACKBURN POINT FL NOAA Chart: 11424 Latitude: 27° 10.7' N ( 27.17830) USGS Quad: LAUREL Longitude: 82° 29.7' W ( -82.49500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: F 634 2005 DESIGNATION: F 634 MONUMENTATION: Flange-encased Rod VM#: 19935 AGENCY: National Geodetic Survey (NGS) IDB PID#: DJ3106 SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 27° 10.8' N ( 27.17997) LONGITUDE: 82° 28.9' W ( -82.48225) The bench mark is a stainless steel rod located 33.83 m (111.0 ft) north of the approximate centerline of Blackburn Point Road, 10.39 m (34.1 ft) east-NE of the approximate centerline of U.S. Highway 41 southbound, 9.60 m (31.5 ft) west-SW of the approximate centerline of U.S. Highway 41 northbound, 2.50 m (8.2 ft) north of the south curb face of the north median, and 0.33 m (1.1 ft) north of a carsonite witness post. The bench mark is a stainless steel rod driven to refusal at a depth of 9.75 m (32.0 ft) with an NGS logo cap flush with the ground and about 0.15 m (0.5 ft) above the level of U.S. Highway 41, the datum point being recessed 0.13 m (0.42 ft) below the level of the NGS logo cap.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 7 Station ID: 8725943 PUBLICATION DATE: 06/03/2011 Name: BLACKBURN POINT FL NOAA Chart: 11424 Latitude: 27° 10.7' N ( 27.17830) USGS Quad: LAUREL Longitude: 82° 29.7' W ( -82.49500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: Z 699 2007 DESIGNATION: Z 699 MONUMENTATION: Survey disk VM#: 19936 AGENCY: Florida Dept. of Environmental Protection (FLDEP) IDB PID#: DL2737 SETTING CLASSIFICATION: Round concrete monument OPUS PID: LATITUDE: 27° 10.0' N ( 27.16725) LONGITUDE: 82° 29.5' W ( -82.49106) The bench mark is a disk set in the top of a round concrete monument flush with the ground and level with Casey Key Road (State Road 789), 12.3 m (40.5 ft) north of the approximate extended centerline of the southernmost driveway at 3311 Casey Key Road (State Road 789), 10.2 m (33.4 ft) south of the approximate extended centerline of the northernmost driveway at 3311 Casey Key Road (State Road 789), 5.3 m (17.4 ft) east-NE of the approximate centerline of Casey Key Road (State Road 789), and 0.4 m (1.4 ft) west of a carsonite witness post.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 7 Station ID: 8725943 PUBLICATION DATE: 06/03/2011 Name: BLACKBURN POINT FL NOAA Chart: 11424 Latitude: 27° 10.7' N ( 27.17830) USGS Quad: LAUREL Longitude: 82° 29.7' W ( -82.49500) T I D A L B E N C H M A R K S BENCH MARK STAMPING: DESIGNATION: CREEK BRIDGE ALIAS: NO STAMPING MONUMENTATION: Survey disk VM#: 19937 AGENCY: Florida Department of Transportation (FLDT) IDB PID#: SETTING CLASSIFICATION: Bridge abutment curb OPUS PID: LATITUDE: 27° 10.1' N ( 27.16831) LONGITUDE: 82° 28.6' W ( -82.47703) The bench mark is a disk set flush in the top of the SE bridge abutment curb about 0.15 m (0.5 ft) above the level of U.S. highway 41, 28.65 m (94.0 ft) NW of a power pole, 7.35 m (24.1 ft) east-NE of the approximate centerline of U.S. Highway 41 northbound, and 0.18 m (0.6 ft) south of the SE end of a concrete guardrail.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 7 Station ID: 8725943 PUBLICATION DATE: 06/03/2011 Name: BLACKBURN POINT FL NOAA Chart: 11424 Latitude: 27° 10.7' N ( 27.17830) USGS Quad: LAUREL Longitude: 82° 29.7' W ( -82.49500) T I D A L D A T U M S Tidal datums at BLACKBURN POINT based on: LENGTH OF SERIES: 4 MONTHS TIME PERIOD: July 1977 - October 1977 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8725110 NAPLES, GULF OF MEXICO Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: MEAN HIGHER HIGH WATER MHHW = 0.516 North American Vertical Datum NAVD88 = 0.482 MEAN HIGH WATER MHW = 0.426 MEAN TIDE LEVEL MTL = 0.271 MEAN SEA LEVEL MSL = 0.265 MEAN LOW WATER MLW = 0.116 MEAN LOWER LOW WATER MLLW = 0.000 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 1 1973 2.859 2.433 5943 H 1983 2.662 2.236 F 634 2005 5.778 5.352 Z 699 2007 3.044 2.618 CREEK BRIDGE 3.347 2.921 Foot Notes: Geodetic heights of the bench marks meet all NOAA/NOS/NGS quality control standards for Second Order, Class 1 leveling. It is advised that a confirmation set of levels be established for bench marks CREEK BRIDGE, F 634 2005, and Z 699 2007 to verify height differences before using tidal bench mark elevation information.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 7 of 7 Station ID: 8725943 PUBLICATION DATE: 06/03/2011 Name: BLACKBURN POINT FL NOAA Chart: 11424 Latitude: 27° 10.7' N ( 27.17830) USGS Quad: LAUREL Longitude: 82° 29.7' W ( -82.49500) 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.