USGS - science for a changing world

Access USGS - San Francisco Bay and Delta

Main Page
Background
Methods
Site Info
Database
Access Home
Continuous Monitoring in the San Francisco Bay and Delta
D.Schoellhamer and P.Buchanan
Installation Sites
SUISUN BAY SAN PABLO BAY CENTRAL BAY SOUTH BAY
Mallard Island Carquinez Bridge Point San Pablo Channel Marker 17
Benicia Bridge Mare Island Causeway Pier 24 Dumbarton Bridge
Martinez Channel Marker 9 Golden Gate Bridge San Mateo Bridge
Presidio
Suisun Bay Installations
Map of Suisun BaySuspended-solids concentration data have been collected at three sites in Suisun Bay: Suisun Bay at Mallard Island, Carquinez Strait at Benicia Bridge, and the Martinez Marina fishing pier. Suspended-solids monitoring equipment was installed at the Mallard Island and the Martinez sites during water year 1994, and the Benicia Bridge site was established during water year 1996. The monitoring site at the Martinez Marina fishing pier was discontinued in water year 1996 because the data from the Benicia Bridge was considered more representative of suspended-solids concentration in Carquinez Strait (Buchanan and Schoellhamer, 1998).
Mallard Island
Self-cleaning suspended-solids concentration monitoring equipment was installed at the DWR Mallard Island Compliance Monitoring Station on February 8, 1994 (lat. 38°02'34", long. 121°55'09"). This site is about 5 miles downstream from the confluence of the Sacramento and San Joaquin Rivers and is at the north shore of Mallard Island near the eastern boundary of Honker Bay, an embayment of Suisun Bay. The station was constructed in the early 1980's by DWR on Pacific Gas and Electric (PG&E) property, and data were first recorded at the station in January 1984.       

Sensors were positioned at near-bottom (5 feet above the bottom) and near-surface (3.3 feet below the surface) to coincide with DWR near-bottom conductance and temperature sensors and near-surface pump intake. The pump intake is attached to a float housed inside a 12-inch PVC pipe and draws water from about 3 feet below the surface. DWR near-surface parameters are measured by sensors submerged in flow-through chambers inside the gage house. This configuration allows the USGS to use DWR data for parameters other than turbidity and saves the cost of installing duplicate sets of sensors. DWR also monitors stage, pH, chlorophyll concentration, and meteorological parameters. Mean lower low water depth at this site is about 25 feet.  Specific conductance and temperature data are available from CDEC, the DWR web site.

Benicia Bridge
Suspended-solids concentration monitoring equipment was installed March 15, 1996, at the Benicia Bridge (lat. 38°02'42", long. 122°07'32"). This site is located on Pier 7 of the Benicia Bridge north of the main ship channel. The National Oceanic and Atmospheric Administration (NOAA) operates salinity sensors and an acoustic doppler current profiler near this site. Optical sensors without the self-cleaning function were deployed at near-bottom and near-surface (25 feet and 74 feet above the bottom) to coincide with the elevations of the NOAA sensors. Mean lower low water depth is about 80 feet at the north side of the pier, although the average mean lower low water depths near the pier are about 60 feet. The near-bottom sensor was set 25 feet above the bottom to collect data representative of the average mean lower low water depth. The sensors are suspended between the concrete pier superstructure and the fender boards, an approximate distance of 1 foot PVC carriages attached to 1/4-inch stainless-steel line are anchored to a 125-pound weight and are used to suspend the sensors at the desired depth. AC power is available at this site and is used to charge a 12-volt, 12-amp/hour battery that powers the data logger and sensors. The instruments are housed in a 3- by 2- by 1-foot weather-proof shelter mounted on the pier.
Martinez
Suspended-solids concentration monitoring equipment was installed at the DWR Martinez Compliance Monitoring Station on February 8, 1994 (lat. 38°01'40", long. 122°08'22").  This site is at the end of the Martinez Marina fishing pier at the south shore of the Carquinez Strait where it widens into Suisun Bay.  The station was constructed in the early 1980's by DWR on City of Martinez property, and, in May 1983, data were first recorded.

An OBS sensor was positioned at near-surface (27.7 feet above the bottom) to coincide with the placement of DWR sensors.  Specific-conductance and temperature data are available from CDEC, the DWR web site.  Mean lower-low water depth at this site is about 31 feet.

Top
Top
San Pablo Bay Installations
Carquinez Bridge
Suspended-sediment monitoring equipment was installed April 21, 1998, at the Carquinez Bridge. This site is located on the north side of the center pier structure of the Carquinez Bridge (fig. 1). Sondes with optical, specific conductance, temperature, and depth sensors were deployed at near-bottom and mid-depths (5 ft and 48 ft, respectively, from the bottom). Mean lower low water depth at this site was about 88 ft. The sensors were suspended between the concrete pier superstructure and the fender boards, which were approximately 1 ft apart. PVC carriages attached to 1/4-in. stainless-steel line were anchored to a 250-pound (lb) weight and used to suspend the sensors at the desired depth. Sensor timing and data storage were controlled by an internal data logger powered by 8 size-C alkaline batteries that were replaced during site visits. No instrument shelter was needed at this site.

Mare Island Causeway
The USGS maintains a monitoring site on the Napa River at Mare Island Causeway near Vallejo (fig. 1). The USGS established this site in cooperation with the California Coastal Conservancy in water year 1998. The USGS assumed full operation of this site in water year 1999. Optical sensors were installed at Mare Island Causeway on October 1, 1998, and were positioned at near-bottom and mid-depth (5 ft and 15 ft, respectively, from the bottom). Mean lower low water depth at this site was about 30 ft. Specific conductance and temperature data were collected at near-bottom and near-surface points in the water column (near-bottom and near- surface depths were sampled to define the vertical stratification). Sensor timing and data storage were controlled by a data logger. PVC carriages attached to 1/4-in. stainless-steel line were anchored to a 125-lb weight and were used to suspend the sensors at the desired depth. AC power charged a 12-V, 12-Ah battery that powered the data logger and sensors. The data logger and peripheral equipment were housed in a 3X2X1-ft plastic weather-proof shelter mounted on a catwalk underneath the causeway.
Channel Marker 9
Suspended-sediment monitoring equipment was installed November 12, 1998, at USCG Channel Marker 9. This site was located in the navigation channel leading to the Petaluma River in the northwest corner of San Pablo Bay (fig. 1). A sonde with optical, specific conductance, temperature, and depth sensors was deployed at near- bottom depth (2 ft above the bottom). Mean lower low water depth at this site was about 6 ft. The sensor was suspended from the channel marker platform using a PVC carriage attached to 1/4-in. stainless-steel line anchored to a 125-lb weight. Sensor timing and data storage were controlled by an internal data logger powered by 8 size-C alkaline batteries that were replaced during site visits. No instrument shelter was needed at this site.
Top
Top
Central San Francisco Bay Installations
Map of Central BaySuspended-solids concentration data have been collected at three sites in Central San Francisco Bay: San Pablo Strait at Point San Pablo, Pier 24 at San Francisco, and the south tower of the Golden Gate Bridge.  Temperature and specific-conductance data have been collected at four sites in the Central San Francisco Bay: San Pablo Strait at Point San Pablo, Pier 24 at San Francisco, the south tower of the Golden Gate Bridge, and San Francisco Bay at Presidio Military Reservation.  A water level record is collected at San Pablo Strait at Point San Pablo.
Point San Pablo
The USGS maintains a monitoring station at San Pablo Strait on the northern end of the Richmond Terminal no. 4 pier (lat. 37°57'53", long. 122°25'42") on the western side of Point San Pablo. The station is equipped with suspended-solids monitoring equipment, electrical conductivity probes, temperature probes, and gage height equipment.  The USGS took over operation of this station from the DWR in October 1989. Data collected prior to October 1, 1989, can be obtained from the California Data Exchange Center, CDEC, a DWR webpage.

Suspended-solids sensors were installed at Point San Pablo on December 1, 1992, and were positioned at near-bottom and mid-depth (3 feet and 13 feet from the bottom). Mean lower low water depth at this site is about 26 feet. Specific-conductance and temperature data (cooperatively funded with DWR) are collected at near-bottom and near-surface points in the water column (near-bottom and near-surface depths are sampled to define the largest stratification). Sensor timing and storage are controlled by a data logger connected to a phone line and modem. Water level is recorded using a float-driven, incremental encoder wired into the data logger, and outside water levels are read using a wire-weight gage.  AC power is available at this site and is used to charge a 12-volt, 60-amp/hour battery that powers the data logger and sensors. The instruments are housed in a 5- by 8- by 8-foot wooden shelter. 

Pier 24
The monitoring station at Pier 24 is on the western end of the San Francisco-Oakland Bay Bridge (lat. 37°47'27", long. 122°23'05") . The USGS took over operation of this station from DWR in October 1989. Data collected prior to October 1, 1989, can be obtained from the California Data Exchange Center, CDEC, a DWR webpage.

Suspended-solids sensors were installed at the Pier 24 site on May 25, 1993, and were positioned at near-bottom and mid-depth (3 feet and 23 feet above the bottom). Mean lower low water depth at this site is about 41 feet. As at the Point San Pablo site, specific-conductance and temperature data (cooperatively funded with DWR) are collected at near-bottom and near-surface points in the water column. Sensor timing and storage are controlled by a data logger connected to a cellular phone and modem. AC power is available at this site and is used to charge two 12-volt, 12-amp/hour batteries that power the instrumentation. The instruments are housed in a corrugated steel shelter.

Golden Gate Bridge
The monitoring station on the Golden Gate Bridge is located on the north side of the south tower fender wall (lat. 37°49'06", long. 122° 28'18"). The south tower is 1,125 feet from the San Francisco shore and marks the southern edge of the main channel. The station was initially established on October 27, 1994, but was not operational until water year 1996 because of numerous complications.  This site was discontinued on February 18, 1998.

The suspended-solids sensors originally were deployed at two points in the water column (5 feet and 45 feet above the bottom). However, the lower sensor cables were being destroyed, probably by the remains of forming material used in the construction of the pier footing that jutted out into the water column and snagged the cables.  Beginning in water year 1996, sensors were deployed at the upper position only.  Mean lower low water depth at this site is about 75 feet and increases to a maximum depth of 378 feet in the main channel. The instruments were housed in a 6- by 6- by 8-foot fiberglass shelter on the pier footing. Sensors were suspended in place using PVC carriages and 3/8-inch stainless-steel line attached to a  600-pound railroad wheel. A data logger and modem were used to control sensor timing, data storage, and retrieval. AC power is available at this site, and all instruments were powered by a 12-volt, 60-amp/hour battery with an AC/DC charger and regulator. In addition to suspended-solids concentrations, specific conductance and temperature (cooperatively funded with DWR) were monitored at near-surface depth.

Presidio
The monitoring station at the Presidio is located at the end of the Coast Guard dock at the Presidio Military Reservation (lat. 37°48'24", long. 122° 27'54").  The USGS took over operation of this station from DWR in October 1990.  Data collected prior to October 1, 1990, can be obtained from the California Data Exchange Center, CDEC, a DWR webpage.  NOAA maintains a tide gauge at this site which has been in operation since 1929, and the data can be obtained from NOAA.

The temperature and specific-conductance sensors (cooperatively funded with DWR) have been deployed at mid-depth in the water column (4 feet above the bottom).  Mean lower low water depth at this site is about 6 feet.  Sensor timing and storage are controlled by a data logger. AC power is available at this site and is used to charge two 12-volt, 12-amp/hour batteries that power the instrumentation. The instruments are housed in a wooden shelter.

Top
Top
South San Francisco Bay Installations
Map of South BaySuspended-solids concentration data have been collected at three sites in South San Francisco Bay. The Channel Marker 17 and the San Mateo Bridge sites were installed during water year 1992.  The Dumbarton Bridge site was installed during water year 1993.  Temperature and specific conductance are monitored only at the San Mateo Bridge.
Channel Marker 17
The southernmost monitoring site in South Bay is at the Coast Guard channel marker 17 (lat. 37°28'44" long. 122°04'38"). Suspended-solids instrumentation was installed on February 26, 1992, and positioned at near-bottom and mid-depth (3 feet and 13 feet from the bottom). Mean lower low water depth at this site is about 25 feet. Sensor cables were protected by a 10-foot length of PVC pipe strapped to the channel marker support column until February 20, 1997 when it was decided that the PVC pipe was causing abrasions in the sensor cables  After February 20, 1997 the sensors were suspended directly from the channel marker platform.  Sensor cables, carriages, and probes are suspended in the water column using a 100-pound weight attached to a 1/4-inch Kevlar reinforced nylon line. The data logger and 12-volt, 12-amp/hour batteries are housed in a 2- by 2- by 1-foot weather-proof enclosure mounted on the channel marker platform.

Dumbarton Bridge
Suspended-solids concentration monitoring equipment was installed on October 21, 1992, at Pier 23 of the Dumbarton Bridge on the west side of the ship channel (lat. 37°30'15", long. 122°07'10"). Optical sensors were deployed at near-bottom and mid-depth (4 feet and 23 feet above the bottom). Mean lower low water depth is about 45 feet. The sensors are suspended between the concrete pier superstructure and the fender boards, which are approximately 3 feet apart. PVC carriages, attached to 1/4-inch Kevlar- reinforced-nylon line, are anchored to a 100-pound weight and are used to suspend the sensors at the desired depth.  AC power is available at this site and is used to charge a 12-volt, 12-amp/hour battery that powers the instrumentation. The instrumentation is housed in a 3- by 2- by 1-foot weather-proof shelter mounted on the pier.  Salinity and temperature data from instruments on a nearby fishing peir are available from a different USGS office (Schemel, 1995).
San Mateo Bridge
The monitoring station on the San Mateo Bridge is at Pier 20 on the east side of the ship channel (lat. 37°35'04", long. 122°14'59"). This station originally was operated by DWR, but the USGS took over operations in October 1989. Data collected prior to October 1, 1989, can be obtained from the California Data Exchange Center, CDEC, a DWR webpage.

The suspended-solids sensors were installed on December 23, 1991, and were positioned at near-bottom and mid-depth (8 feet and 29 feet above the bottom). Mean lower low water depth at this site is about 48 feet. The instruments are housed in an 8- by 6- by 8-foot wooden shelter on the pier, which is surrounded by a protective fender structure. The sensors are deployed between the pier and the fender, and flow past the sensors is affected to some degree by the pilings and the concrete superstructure. Sensors are suspended in place using PVC carriages and stainless-steel line attached to a 200-pound weight. AC power is available at this site and is used to charge a 12-volt, 60-amp/hour battery that powers the data logger and sensors. In addition to suspended-solids concentrations, specific conductance and temperature (cooperatively funded with DWR) are monitored at near-bottom and near-surface depths.

Top
Top

Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USAGov: Government Made Easy U.S. Department of the Interior | U.S. Geological Survey
URL:http://sfbay.wr.usgs.gov/sediment/cont_monitoring/site_info.html
Page Last Modified: Thursday, 13-Dec-2007 12:22:31 PST