The U.S. Geological Survey maintains a program of water-quality studies in San Francisco Bay (CA) that began in 1969. This USGS Data Release archives and makes available all measurements from 2016-2021. Water-quality constituent measurements were collected aboard a research vessel. Sensor constituents include salinity, temperature, oxygen, and light attenuation coefficient. From these constituents, three parameters are derived: ratio of chlorophyll-a and pheopigments, oxygen percent saturation, and density as Sigma-t. Water sample constituents collected for later analysis include chlorophyll-a, suspended particulate matter, nitrate, nitrite, ammonium, silicate and phosphate. These discrete water samples were collected at near surface (2m) by a fixed depth pump or at depth using a Niskin water sampler on a depth-marked line. The sampling was conducted monthly at 37 fixed sampling locations along a 145-km transect from lower South San Francisco Bay to the lower Sacramento River. Additional sampling cruises at a subset of stations (South and Central Bay) were conducted 0-3 times a month. All stations are listed in the station location table (SFBay_TableofStationLocations.csv) and standard stations are shown on the map (sfbaymap.jpg). A prior USGS Data Release contains the 1969-2015 data https://www.sciencebase.gov/catalog/item/5841f97ee4b04fc80e518d9f. The project website contains more details about this research program and data collection https://sfbay.wr.usgs.gov/access/wqdata/. The website includes a public database where data from all program years can be accessed and downloaded https://sfbay.wr.usgs.gov/water-quality-database/ Please see the VersionHistory.txt for a detailed list of the updates from previous versions.

The U.S. Geological Survey maintains a program of water-quality studies in San Francisco Bay (CA) that began in 1969. This Data Release archives and makes available all measurements made from 1969 through 2015. Water-quality constituents include salinity, temperature, light extinction coefficient, chlorophyll-a, dissolved oxygen, suspended particulate matter, nitrate, nitrite, ammonium, silicate and phosphate. Time, Julian date, and three constituents were added retroactively in 2023 to all years: ratio of chlorophyll-a and pheopigments, oxygen percent saturation, and density as Sigma-t. Water samples were collected along a 145-km transect from lower South San Francisco Bay to the lower Sacramento River. Samples were collected at 59 fixed sampling locations, of these 37 became standard long-term sampling stations. All stations are listed in the station location table (SFBstationlocations_19692015.csv) and standard stations are shown on the map (sfbaymap.jpg)

The U.S. Geological Survey maintains a program of water-quality studies in San Francisco Bay (CA) that began in 1969. We plan a USGS Data Release to archive and make available all measurements made from 1969 through 2015. Water-quality constituents include salinity, temperature, light attenuation coefficient, and concentrations of chlorophyll-a, dissolved oxygen, suspended particulate matter, nitrate, nitrite, ammonium, silicate and phosphate. Water samples are collected at 37 fixed sampling locations along a 145-km transect from lower South San Francisco Bayo the lower Sacramento River. A map of sampling locations is available on the project website at: https://sfbay.wr.usgs.gov/access/wqdata/overview/wherewhen/stnmap.html

The U.S. Geological Survey maintains a program of water-quality studies in San Francisco Bay (CA) that began in 1969. We plan a USGS Data Release to archive and make available all measurements made from 1969 through 2015. Water-quality constituents include salinity, temperature, light attenuation coefficient, and concentrations of chlorophyll-a, dissolved oxygen, suspended particulate matter, nitrate, nitrite, ammonium, silicate and phosphate. Water samples are collected at 37 fixed sampling locations along a 145-km transect from lower South San Francisco Bayo the lower Sacramento River. A map of sampling locations is available on the project website at: https://sfbay.wr.usgs.gov/access/wqdata/overview/wherewhen/stnmap.html

The dataset documents the spatial and temporal variability of nutrients and related water quality parameters at high spatial resolution in the San Francisco Bay of California, USA in 2021 and 2022. The dataset includes nitrate, temperature, conductivity, dissolved oxygen, and chlorophyll as well as information about phytoplankton community composition. Data-collection cruises were conducted under different environmental/flow conditions. Version history: On 3/15/24, the provisional data files hosted on this webpage were removed, and replaced with updated finalized files.

The dataset documents the spatial and temporal variability of nutrients and related water quality parameters at high spatial resolution in the San Francisco Bay of California, USA in 2021 and 2022. The dataset includes nitrate, temperature, conductivity, dissolved oxygen, and chlorophyll as well as information about phytoplankton community composition. Data-collection cruises were conducted under different environmental/flow conditions. Version history: On 3/15/24, the provisional data files hosted on this webpage were removed, and replaced with updated finalized files.

The dataset documents the spatial and temporal variability of nutrients and related water quality parameters at high spatial resolution in the San Francisco Bay of California, USA in 2021 and 2022. The dataset includes nitrate, temperature, conductivity, dissolved oxygen, and chlorophyll as well as information about phytoplankton community composition. Data-collection cruises were conducted under different environmental/flow conditions. Version history: On 3/15/24, the provisional data files hosted on this webpage were removed, and replaced with updated finalized files.

This data package was created 2025-01-27 13:30:01 by NPSTORET and includes selected project, location, and result data. Data contained in the San Francisco Bay Area Network NPSTORET back-end file (SFAN_NPSTORET_BACKEND_20250121.ACCDB) were filtered to include: Organization: - SFAN: San Francisco Bay Area Network Project: - SFAN_I&M: SFAN Long-Term Water Quality Monitoring Program - SFAN_I&M_EXTRA: SFAN Long-Term Water Quality Monitoring Program, Extra Sampling - SFAN_WQ: SFAN Pilot Monitoring for Freshwater Quality Protocol Station: - Include Trip QC And All Station Visit Results Activity Start Date (>=1/1/1901 and <=9/30/2024) Value Status: - Accepted or Certified (exported as Final) or Verified (exported as Final) or Final The data package is organized into five data tables: - Projects.csv - describes the purpose and background of the monitoring efforts - Locations.csv - documents the attributes of the monitoring locations/stations - Results.csv - contains the field measurements, observations, and/or lab analyses for each sample/event/data grouping - HUC.csv - enumerates the domain of allowed values for 8-digit and 12-digit hydrologic unit codes utilized by the Locations datatable - Characteristics.csv - enumerates the domain of characteristics available in NPSTORET to identify what was sampled, measured or observed in Results Period of record for filtered data is 2003-06-18 to 2024-09-25. This data package is a snapshot in time of multiple National Park Service projects. The most current data for these projects, which may be more or less extensive than that in this data package, can be found on the Water Quality Portal at: https://www.waterqualitydata.us/data/Result/search?project=SFAN_I&M https://www.waterqualitydata.us/data/Result/search?project=SFAN_I&M_EXTRA https://www.waterqualitydata.us/data/Result/search?project=SFAN_WQ

This data package was created 2025-01-27 13:30:01 by NPSTORET and includes selected project, location, and result data. Data contained in the San Francisco Bay Area Network NPSTORET back-end file (SFAN_NPSTORET_BACKEND_20250121.ACCDB) were filtered to include: Organization: - SFAN: San Francisco Bay Area Network Project: - SFAN_I&M: SFAN Long-Term Water Quality Monitoring Program - SFAN_I&M_EXTRA: SFAN Long-Term Water Quality Monitoring Program, Extra Sampling - SFAN_WQ: SFAN Pilot Monitoring for Freshwater Quality Protocol Station: - Include Trip QC And All Station Visit Results Activity Start Date (>=1/1/1901 and <=9/30/2024) Value Status: - Accepted or Certified (exported as Final) or Verified (exported as Final) or Final The data package is organized into five data tables: - Projects.csv - describes the purpose and background of the monitoring efforts - Locations.csv - documents the attributes of the monitoring locations/stations - Results.csv - contains the field measurements, observations, and/or lab analyses for each sample/event/data grouping - HUC.csv - enumerates the domain of allowed values for 8-digit and 12-digit hydrologic unit codes utilized by the Locations datatable - Characteristics.csv - enumerates the domain of characteristics available in NPSTORET to identify what was sampled, measured or observed in Results Period of record for filtered data is 2003-06-18 to 2024-09-25. This data package is a snapshot in time of multiple National Park Service projects. The most current data for these projects, which may be more or less extensive than that in this data package, can be found on the Water Quality Portal at: https://www.waterqualitydata.us/data/Result/search?project=SFAN_I&M https://www.waterqualitydata.us/data/Result/search?project=SFAN_I&M_EXTRA https://www.waterqualitydata.us/data/Result/search?project=SFAN_WQ

The U.S. Geological Survey collected samples from 50 public supply wells during two distinct sampling episodes (2004-2005 and 2014) on the North-Central California coast. During each sampling episode, the samples were analyzed for 160 water-quality constituents, including water-quality indicators, nutrients, major and minor ions, trace elements, volatile organic compounds, and pesticide compounds. The paired-sample results were submitted to an evaluation method to determine whether or not step trends had occurred in the concentrations of each constituent. Quality-control samples were collected at a subset of the wells. The datasets presented here consist of a list and description of the 160 constituents, an Excel workbook which details the step trend evaluation method, and a summary of the quality-control data results.