U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Datums Page Page 1 of 5 PUBLICATION DATE: 12/21/1984 Station ID: 9418723 SUPERCEDED DATE: 04/21/2003 Name: FIELDS LANDING, HUMBOLDT BAY CALIFORNIA NOAA Chart: 18622 Latitude: 40° 43.4' N USGS Quad: FIELDS LANDING Longitude: 124° 13.3' W To reach the tidal bench marks from U.S. Highway 101, proceed 7.0 miles (11.3 km) south of Eureka exit at Fields Landing Road south, west of South Depot Road before freeway on ramp, and continue until road deadends at a private road at a wooden wharf. The tide gage and staff were located on the inside of the north corner of the wharf adjacent to channel mark 11. T I D A L B E N C H M A R K S PRIMARY BENCH MARK STAMPING: 8723 A 1978 MONUMENTATION: Survey Disk VM#: 8710 AGENCY: PID#: LV0656 SETTING CLASSIFICATION: Galvanized Steel Rod The bench mark is 104.0 feet (31.7 m) south of the centerline of Railroad Avenue, 15.0 feet (4.6 m) east of the curb of the parking lot, and 13.0 feet (4.0 m) SW from the SW corner of the bathroom at the launching ramp. The bench mark is on a rod driven to 52.0 feet (15.8 m), encased in concrete and a PVC pipe. BENCH MARK STAMPING: 1929 5 MONUMENTATION: Survey Disk VM#: 8711 AGENCY: PID: SETTING CLASSIFICATION: Concrete Sidewalk The bench mark is set in a concrete sidewalk than runs north- south through Charlie Peterson Place in NE corner lot at Railroad and Second Streets, 97.4 feet (29.7 m) east of the centerline of Second Street, 7.0 feet (2.1 m) north of the outer edge of the sidewalk along Railroad Street, and 0.6 foot (0.2 m) west of the east edge of Peterson walk just inside at the gate. U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 2 of 5 PUBLICATION DATE: 12/21/1984 Station ID: 9418723 SUPERCEDED DATE: 04/21/2003 Name: FIELDS LANDING, HUMBOLDT BAY CALIFORNIA NOAA Chart: 18622 Latitude: 40° 43.4' N USGS Quad: FIELDS LANDING Longitude: 124° 13.3' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: NO 7 RESET 1961 MONUMENTATION: Survey Disk VM#: 8712 AGENCY: PID#: LV0655 SETTING CLASSIFICATION: Curb The bench mark is set in top of the curb around a flower box at the Silver Side Motel, 75.0 feet (22.9 m) west of the centerline of U.S. Highway 101, 3.5 feet (10.7 m) south of the centerline of Central Avenue, and 3.0 feet (0.9 m) south of the NE corner of the motel buildings. BENCH MARK STAMPING: NO 8 RESET 1961 MONUMENTATION: Survey Disk VM#: 8713 AGENCY: PID: SETTING CLASSIFICATION: Curb The bench mark is set in top of the curb at the north side of the post office, 80.0 feet (24.4 m) west of the centerline of U.S. Highway 101, 25.0 feet (7.6 m) south of the centerline of Railroad Avenue, and 6.0 feet (1.8 m) west of the NE corner of the post office. BENCH MARK STAMPING: P 1087 1967 MONUMENTATION: Survey Disk VM#: 8714 AGENCY: PID#: LV0263 SETTING CLASSIFICATION: Concrete Guardrail The bench mark is set in top of the east concrete guardrail of the Orchard Avenue overpass 4.122 at highway mileage post 72.03, 18.0 feet (5.5 m) east of the centerline of the east lanes of the highway, 1.0 feet (0.3 m) north of the south end of the east guardrail of Orchard Avenue overpass 4.122, and 3.5 feet (1.1 m) above the highway. U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 3 of 5 PUBLICATION DATE: 12/21/1984 Station ID: 9418723 SUPERCEDED DATE: 04/21/2003 Name: FIELDS LANDING, HUMBOLDT BAY CALIFORNIA NOAA Chart: 18622 Latitude: 40° 43.4' N USGS Quad: FIELDS LANDING Longitude: 124° 13.3' W T I D A L B E N C H M A R K S BENCH MARK STAMPING: Q 1087 1967 MONUMENTATION: Survey Disk VM#: 8715 AGENCY: PID#: LV0264 SETTING CLASSIFICATION: Concrete Guardrail The bench mark is set in top of the SW end of the SE concrete guardrail of King Salmon Avenue underpass 4-67R at highway mileage post 72.88, 20.0 feet (6.1 m) SE of the centerline of the SE lanes of the highway, and 3.5 feet (1.1 m) above the ground. U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 4 of 5 PUBLICATION DATE: 12/21/1984 Station ID: 9418723 SUPERCEDED DATE: 04/21/2003 Name: FIELDS LANDING, HUMBOLDT BAY CALIFORNIA NOAA Chart: 18622 Latitude: 40° 43.4' N USGS Quad: FIELDS LANDING Longitude: 124° 13.3' W T I D A L D A T U M S Tidal datums at FIELDS LANDING, HUMBOLDT BAY based on: LENGTH OF SERIES: 9 MONTHS TIME PERIOD: APRIL 1978 - JANUARY 1979 TIDAL EPOCH: 1960-1978 CONTROL TIDE STATION: 9419750 CRESCENT CITY Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in FEET: HIGHEST OBSERVED WATER LEVEL (12/28/1978) = 8.28 MEAN HIGHER HIGH WATER MHHW = 6.85 MEAN HIGH WATER MHW = 6.15 NATIONAL GEODETIC VERTICAL DATUM NGVD29 = 3.70 MEAN TIDE LEVEL MTL = 3.69 MEAN LOW WATER MLW = 1.23 MEAN LOWER LOW WATER MLLW = 0.00 LOWEST OBSERVED WATER LEVEL (05/24/1978) = -2.40 North American Vertical Datum (NAVD88) Bench Mark Elevation Information In FEET above: Stamping or Designation MLLW MHW 8723 A 1978 12.40 6.25 1929 5 8.21 2.06 NO 7 RESET 1961 10.81 4.66 NO 8 RESET 1961 10.43 4.28 P 1087 1967 35.97 29.82 Q 1087 1967 32.62 26.47 U.S. DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration National Ocean Service Page 5 of 5 PUBLICATION DATE: 12/21/1984 Station ID: 9418723 SUPERCEDED DATE: 04/21/2003 Name: FIELDS LANDING, HUMBOLDT BAY CALIFORNIA NOAA Chart: 18622 Latitude: 40° 43.4' N USGS Quad: FIELDS LANDING Longitude: 124° 13.3' W 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 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.