U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
Datums Page                                                        Page  1 of  5

                                                                                
Station ID: 9415423                         PUBLICATION DATE:  09/28/2016
Name:       LAKEVILLE, PETALUMA RIVER                         
            CA
NOAA Chart: 18654                           Latitude:   38° 11.9' N (  38.19830)
USGS Quad:  PETALUMA RIVER                  Longitude: 122° 32.8' W (-122.54700)


To reach the tidal bench marks proceed 1.8 km (1.1 mi) south of the Lakeville
Grammar School to the Lakeville Marina off Lakeville Road, and then to the
intersection of Lakeville Road and Cannon Lane.  The bench mark are along
Lakeville Road.  The tide gage and staff were located on the wharf at the
Lakeville Marina.


                         T I D A L   B E N C H   M A R K S


                 PRIMARY BENCH MARK STAMPING:  5423 B 1977
                         DESIGNATION:          941 5423 B TIDAL

MONUMENTATION:           DJ                                    VM#:         8663
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:                                        OPUS PID:        
LATITUDE:   38° 11.8' N (  38.19744)          LONGITUDE: 122° 32.8' W (-122.54611)


The primary bench mark is located 59.40 m (194.9 ft) SE of the Papa's
Taverna/Lakeville Marina sign, 15.07 m (49.4 ft) east of a wooden light pole,
and 6.95 m (22.8 ft) SW of the centerline of Lakeville Highway. The bench mark
is a NOAA brass disk crimped to the top of a copper-clad steel rod driven 7.9 m
(26.0 ft) to refusal in a PVC sleeve that extends 0.06 m (0.2 ft) above ground
on the south side of the driveway near the SW edge of Lakeville Highway.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  2 of  5

                                                                                
Station ID: 9415423                         PUBLICATION DATE:  09/28/2016
Name:       LAKEVILLE, PETALUMA RIVER                         
            CA
NOAA Chart: 18654                           Latitude:   38° 11.9' N (  38.19830)
USGS Quad:  PETALUMA RIVER                  Longitude: 122° 32.8' W (-122.54700)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  5423 C 1977
                         DESIGNATION:          941 5423 C TIDAL

MONUMENTATION:           DJ                                    VM#:         8664
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:                                        OPUS PID#: BBCN75
LATITUDE:   38° 11.8' N (  38.19664)          LONGITUDE: 122° 32.7' W (-122.54567)


The bench mark is located 9.39 m (30.8 ft) SW of the centerline of Lakeville
Highway and 8.73 m (28.6 ft) west of the end of a guard rail. The bench mark is
a brass disk crimped to the top of a copper-clad steel rod driven 8.8 m (28.9
ft) to refusal and inside a PVC sleeve that extends 0.21 m (0.7 ft) above ground
near the SW edge of Lakeville Highway



                         BENCH MARK STAMPING:  5423 D 1977
                         DESIGNATION:          941 5423 D TIDAL

MONUMENTATION:           DJ                                    VM#:         8665
AGENCY:                  National Ocean Survey (NOS)           IDB PID#:        
SETTING CLASSIFICATION:                                        OPUS PID#: BBDJ89
LATITUDE:   38° 11.7' N (  38.19514)          LONGITUDE: 122° 32.7' W (-122.54472)


The bench mark is located 70.82 meters (232.4 ft) NW of stop sign at Lakeville
Hwy and Cannon Lane, 23.25 m (76.3 ft) north of a gate post, and 12.88 m (42.3
ft) NW of power pole #153. The bench mark is a brass disk crimped to the top of
a copper-clad steel rod driven 5.8 m (19.0 ft) to refusal and inside a PVC
sleeve that extends 0.30 m (1.0 ft) above ground near the SW edge of Lakeville
Highway.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  3 of  5

                                                                                
Station ID: 9415423                         PUBLICATION DATE:  09/28/2016
Name:       LAKEVILLE, PETALUMA RIVER                         
            CA
NOAA Chart: 18654                           Latitude:   38° 11.9' N (  38.19830)
USGS Quad:  PETALUMA RIVER                  Longitude: 122° 32.8' W (-122.54700)


                         T I D A L   B E N C H   M A R K S


                         BENCH MARK STAMPING:  LAKEVILLE 1996 RCE 15310

MONUMENTATION:           DB                                    VM#:        22015
AGENCY:                  U.S. Army Corps of Engineers (USACE)  IDB PID#:        
SETTING CLASSIFICATION:                                        OPUS PID#: BBDJ86
LATITUDE:   38° 11.9' N (  38.19756)          LONGITUDE: 122° 32.9' W (-122.54753)


The bench mark is a brass disk set in concrete located 39.60 m (129.9 ft) SW of
the west corner of a blue and yellow building (bar), 14.71 m (48.3 ft) west of a
wooden fence with angle points and a wooden light post, and 5.32 m (17.5 ft)
north of a small marina pay building.

                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  4 of  5

                                                                                
Station ID: 9415423                         PUBLICATION DATE:  09/28/2016
Name:       LAKEVILLE, PETALUMA RIVER                         
            CA
NOAA Chart: 18654                           Latitude:   38° 11.9' N (  38.19830)
USGS Quad:  PETALUMA RIVER                  Longitude: 122° 32.8' W (-122.54700)


                            T I D A L   D A T U M S 


Tidal datums at LAKEVILLE, PETALUMA RIVER based on:

     LENGTH OF SERIES:      3 MONTHS
     TIME PERIOD:           April 2014 - June 2014
     TIDAL EPOCH:           1983-2001
     CONTROL TIDE STATION:  9414290 SAN FRANCISCO, SAN FRANCISCO BAY


Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:

     MEAN HIGHER HIGH WATER                     MHHW   =  1.941
     MEAN HIGH WATER                            MHW    =  1.791
     MEAN SEA LEVEL                             MSL    =  1.049
     MEAN TIDE LEVEL                            MTL    =  1.031
     MEAN LOW WATER                             MLW    =  0.271
     MEAN LOWER LOW WATER                       MLLW   =  0.000

North American Vertical Datum (NAVD88)

Bench Mark Elevation Information                In METERS above:

     Stamping or Designation                    MLLW        MHW

     5423 B 1977                                 2.489    0.698
     5423 C 1977                                 2.195    0.404
     5423 D 1977                                 2.130    0.339
     LAKEVILLE 1996 RCE 15310                    2.471    0.680


                          U.S. DEPARTMENT OF COMMERCE
                National Oceanic and Atmospheric Administration
                            National Ocean Service
                                                                   Page  5 of  5

                                                                                
Station ID: 9415423                         PUBLICATION DATE:  09/28/2016
Name:       LAKEVILLE, PETALUMA RIVER                         
            CA
NOAA Chart: 18654                           Latitude:   38° 11.9' N (  38.19830)
USGS Quad:  PETALUMA RIVER                  Longitude: 122° 32.8' W (-122.54700)


                             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.