U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 6 Station ID: 8761993 PUBLICATION DATE: 11/09/2011 Name: TCHEFUNCTA RIVER, LAKE PONT LA NOAA Chart: 11369 Latitude: 30° 22.7' N ( 30.37830) USGS Quad: MADISONVILLE Longitude: 90° 9.6' W ( -90.16000) To reach the tidal bench marks from the intersection of State Highways 1077 and 22 in Madisonville, proceed south on State Highway 1077 for 3.4 km (2.1 mi) to the Town of Madisonville Recreation Area. The bench marks are in the vicinity of the recreation area and north along State Highway 1077. The tide gage and staff were located at the NE end of the northernmost dock of the covered boat house at the recreation area. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 1993 A 1982 DESIGNATION: 876 1993 A MONUMENTATION: Tidal Station disk VM#: 10864 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 30° 22.7' N ( 30.37830) LONGITUDE: 90° 9.6' W ( -90.16000) The primary bench mark is a disk located on the south side of the parking lot across the road from the boat house at the Town of Madisonville Recreation Area, 112 m (366 ft) ENE of bench mark WES 14 1978, 18 m (60 ft) NW of the wood seawall, 3 m (9 ft) west of a utility pole, and 2 m (8 ft) NW of a fence line. The bench mark is set 0.12 m (0.4 ft) below ground level, crimped to the top of a stainless steel rod driven 19.5 m (64 ft) to substantial resistance, and encased in a 4-inch PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 6 Station ID: 8761993 PUBLICATION DATE: 11/09/2011 Name: TCHEFUNCTA RIVER, LAKE PONT LA NOAA Chart: 11369 Latitude: 30° 22.7' N ( 30.37830) USGS Quad: MADISONVILLE Longitude: 90° 9.6' W ( -90.16000) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 1993 B 1982 DESIGNATION: 876 1993 B MONUMENTATION: Tidal Station disk VM#: 10865 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 30° 22.7' N ( 30.37830) LONGITUDE: 90° 9.6' W ( -90.16000) The bench mark is a disk located north of the recreation area, 43 m (141 ft) north of the NW corner of the boat ramp, 24 m (80 ft) NNE of a utility pole, 15 m (50 ft) WNW of the west shoreline of Tchefuncta River, and 7 m (24 ft) WNW of the centerline of State Highway 1077. The bench mark is set 9 cm (0.3 ft) below ground level, crimped to the top of a stainless steel rod driven 19.5 m (64 ft) to substantial resistance, and encased in a 4-inch PVC pipe and concrete kickblock. BENCH MARK STAMPING: 1993 C 1982 DESIGNATION: 876 1993 C MONUMENTATION: Tidal Station disk VM#: 10866 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 30° 22.7' N ( 30.37830) LONGITUDE: 90° 9.6' W ( -90.16000) The bench mark is a disk located on the west side of the parking lot at the recreation area, 106 m (348 ft) WNW of the centerline of State Highway 1077, 95 m (312 ft) NW of bench mark 1993 A 1982, and 2 m (6 ft) NNE of the NE corner of the boat ramp parking lot fence. The bench mark is set 9 cm (0.3 ft) below ground level, crimped to the top of a stainless steel rod driven 19.5 m (64 ft) to substantial resistance, and encased in a 4-inch PVC pipe and concrete kickblock.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 6 Station ID: 8761993 PUBLICATION DATE: 11/09/2011 Name: TCHEFUNCTA RIVER, LAKE PONT LA NOAA Chart: 11369 Latitude: 30° 22.7' N ( 30.37830) USGS Quad: MADISONVILLE Longitude: 90° 9.6' W ( -90.16000) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 1993 D 1982 DESIGNATION: 876 1993 D MONUMENTATION: Tidal Station disk VM#: 10867 AGENCY: National Ocean Survey (NOS) IDB PID#: SETTING CLASSIFICATION: Stainless steel rod OPUS PID: LATITUDE: 30° 22.7' N ( 30.37830) LONGITUDE: 90° 9.6' W ( -90.16000) The bench mark is a disk located north of the recreation area, 66 m (218 ft) NNE of bench mark 1993 B 1982, 65 m (213 ft) SSW of the third utility pole north of the boat dock, 30 m (97 ft) NNW of the second utility pole north of the boat dock, 15 m (50 ft) WNW of the west shoreline of Tchefuncta River, and 5 m (18 ft) WNW of the centerline of State Highway 1077. The bench mark is set 9 cm (0.3 ft) below ground level, crimped to the top of a stainless steel rod driven 19.5 m (64 ft) to substantial resistance, and encased in a 4-inch PVC pipe and concrete kickblock. BENCH MARK STAMPING: WES 14A 1978 DESIGNATION: 876 1993 WES 14A MONUMENTATION: Survey disk VM#: 10868 AGENCY: US Army Corps of Engineers (USE) IDB PID#: SETTING CLASSIFICATION: Copper-clad steel rod OPUS PID: LATITUDE: 30° 22.7' N ( 30.37830) LONGITUDE: 90° 9.6' W ( -90.16000) The bench mark is a disk located at the south end of State Road 1077, west of bench mark 1993 A 1982, 22 m (71 ft) north of the NW corner piling of a pole house, 7 m (22 ft) north of the centerline of the road, 3.87 m (12.7 ft) SSE of a utility pole with transformer, and 0.61 m (2.0 ft) south of a fence post with witness sign. The bench mark is crimped to the top of a copper-clad steel rod driven to unknown depth, and encased in a 6-inch PVC pipe.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 6 Station ID: 8761993 PUBLICATION DATE: 11/09/2011 Name: TCHEFUNCTA RIVER, LAKE PONT LA NOAA Chart: 11369 Latitude: 30° 22.7' N ( 30.37830) USGS Quad: MADISONVILLE Longitude: 90° 9.6' W ( -90.16000) T I D A L B E N C H M A R K S BENCH MARK STAMPING: 52 V 011 1977 DESIGNATION: 52 V 011 LADTD MONUMENTATION: Survey disk VM#: 10869 AGENCY: Lousiana Department of Transportation (LADTD) IDB PID#: BJ2852 SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 30° 24.2' N ( 30.40330) LONGITUDE: 90° 9.4' W ( -90.15670) The bench mark is a disk set in a concrete monument in the village of Madisonville, one block east along State Highway 22 from the junction of Highways 21 and 22, 53 m (174 ft) south of the centerline of State Highway 22, 19 m (62 ft) NE of a flag pole at the Madisonville Town Hall, 9 m (29 ft) west of the centerline of Water Street, and 0.3 m (1 ft) west of a witness post. BENCH MARK STAMPING: 52 V 012 1977 DESIGNATION: 52 V 012 LADTD MONUMENTATION: Survey disk VM#: 10870 AGENCY: Lousiana Department of Transportation (LADTD) IDB PID#: BJ2853 SETTING CLASSIFICATION: Concrete monument OPUS PID: LATITUDE: 30° 24.9' N ( 30.41500) LONGITUDE: 90° 9.8' W ( -90.16330) The bench mark is a disk set in a concrete monument, 1.4 km (0.9 mi) north along State Highway 21 from the junction of Highways 21 and 22 in Madisonville, 23 m (77 ft) west of the centerline of State Highway 21, 8 m (26 ft) SW of a 2 m (6 ft) diameter live oak tree in the Theodore Dendinger Memorial Cemetery, and 7 m (24 ft) NW of a 2 m (5 ft) diameter live oak tree.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 6 Station ID: 8761993 PUBLICATION DATE: 11/09/2011 Name: TCHEFUNCTA RIVER, LAKE PONT LA NOAA Chart: 11369 Latitude: 30° 22.7' N ( 30.37830) USGS Quad: MADISONVILLE Longitude: 90° 9.6' W ( -90.16000) T I D A L D A T U M S Tidal datums at TCHEFUNCTA RIVER, LAKE PONT based on: LENGTH OF SERIES: 5 YEARS TIME PERIOD: June 1983 - May 1988 TIDAL EPOCH: 1983-2001 CONTROL TIDE STATION: 8761927 USCG NEW CANAL STA., LAKE PONTCHARTRAIN Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS: HIGHEST OBSERVED WATER LEVEL (01/21/1983) = 1.014 MEAN HIGHER HIGH WATER MHHW = 0.173 MEAN HIGH WATER MHW = 0.172 MEAN SEA LEVEL MSL = 0.088 MEAN TIDE LEVEL MTL = 0.084 MEAN LOWER LOW WATER MLLW = 0.000 MEAN LOW WATER MLW = -0.004 LOWEST OBSERVED WATER LEVEL (04/12/1988) = -0.809 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In METERS above: Stamping or Designation MLLW MHW 1993 A 1982 0.297 0.125 1993 B 1982 0.310 0.138 1993 C 1982 0.219 0.047 1993 D 1982 0.159 -0.013 WES 14A 1978 0.523 0.351 52 V 011 1977 1.528 1.356 52 V 012 1977 3.309 3.137 Foot Notes: Bench marks 52 V 011 1977 and 52 V 012 1977 are based on one differential leveling connection and do not meet the quality control standards of the NOS. Therefore, caution should be used when deriving elevations for these marks.
U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 6 of 6 Station ID: 8761993 PUBLICATION DATE: 11/09/2011 Name: TCHEFUNCTA RIVER, LAKE PONT LA NOAA Chart: 11369 Latitude: 30° 22.7' N ( 30.37830) USGS Quad: MADISONVILLE Longitude: 90° 9.6' W ( -90.16000) 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.