The USGS Monitoring Network and the Continuous Collection of Water Quality Data in the Sacramento-San Joaquin Delta
Water quality in Northern California’s Sacramento-San Joaquin Delta (Delta) is essential to clean drinking water, agricultural activities, and the health of the aquatic food web. Management of this important water resource requires the strategic collection of relevant and timely data. A primary component of this data collection is measuring and monitoring water quality.
USGS monitoring stations have been collecting water quality and flow data in the Delta for almost half a century but parameters have been largely limited to temperature, salinity, and turbidity. In recent years, this work has expanded at several locations to include nutrient measurements and other biologically important water quality parameters (dissolved oxygen, pH, chlorophyll, and dissolved organic matter). In addition, new methods have been developed that use these data to assess habitat quality, productivity, and biogeochemical rates.
The enhanced water quality stations identified in this project are often co-located with hydrodynamic measurements like water stage and flow (velocity, discharge and direction). The value of enhanced water-quality and nutrient measurements at flow stations across the Delta allows for a direct comparison of constituent flux across seasons and water years. The high frequency, real-time data collected at monitoring stations also serve as an early warning system for unanticipated, short-lived, or rapidly changing conditions, such as those due to spills, harmful algal blooms, and altered water-quality resulting from storms or levee breaches.
The characteristics being measured fall into the following categories:
I. Core water-quality data
Core water-quality data parameters include 1] temperature, 2] specific conductance (salinity), and 3] turbidity (sediment), all of which drive biological and ecosystem processes.
Salinity as an indicator of conductance
Fresh water from California rivers mixes with salt water from the Pacific Ocean. This mixing is affected by tides, waves, wind, and freshwater inflow. Salinity, or the saltiness in a body of water, is the main factor in determining conductance. Specific conductance is the measurement that is temperature compensated.
Along with water temperature, identifying gradients of salinity, or specific conductance, is key to understanding changes in an ecosystem as well a significant water management concern.
Turbidity and sediment
Sediment suspended in the water column causes turbidity, which in turn affects light penetration, ecological productivity, and habitat quality.
Sediment from watersheds is delivered downstream and is deposited along the Delta’s shores and tidal wetlands. This process helps maintain wetlands and protects against coastal erosion and the effects of sea-level rise. Sediment also plays a crucial role in the preservation of habitat for wildlife.
The collection of turbidity data is critical in quantifying suspended sediment and its distribution to existing and planned marsh habitats. One example is that turbidity data is used in the creation of numerical models.
II & III. Enhanced water-quality data and Nutrients
Enhanced water-quality data include levels of dissolved oxygen, pH, chlorophyll, dissolved organic carbon, and nutrients that impact aquatic biogeochemical processes. Together with hydrodynamic and core water-quality data, these parameters can favor different species, can determine the health of the food web, and can impact the suitability of water for different uses.
Overview of parameters measured at water quality monitoring stations
The network
The USGS high-resolution (15 minute) fixed monitoring network in the Delta includes over 40 flow stations that are often co-located with ‘core water quality’ . Approximately 14 of these stations include enhanced-water quality monitoring activities maintained by the California Water Science Center (CAWSC) Biogeochemistry Group.
Station name (Abbreviation)
- SACRAMENTO R A FREEPORT CA (FPT)
- SACRAMENTO R AB DELTA CROSS CHANNEL CA (WGA)
- CACHE SLOUGH AB RYER ISLAND FERRY NR RIO VISTA CA (CCH)
- CACHE SLOUGH A S LIBERTY ISLAND NR RIO VISTA CA (LIB)
- TOE DRAIN A LIBERTY ISLAND NR COURTLAND CA (TOW)
- SAN JOAQUIN R A JERSEY POINT CA (JPT)
- SACRAMENTO R DEEP WATER SHIP CHANNEL NR COURTLAND (DWS)
- SACRAMENTO R DEEP WATER SHIP CHANNEL NR FREEPORT (DWF)
- SACRAMENTO R BL TOLAND LANDING NR RIO VISTA CA (TOL)
- SUISUN BAY A VAN SICKLE ISLAND NR PITTSBURG CA (CFL)
- GRIZZLY BAY A SUISUN SLOUGH NR AVON CA (GRZ)
- MIDDLE R AT MIDDLE RIVER CA (MDM)
- LITTLE POTATO SLOUGH A TERMINOUS CA (LPS)
- FIRST MALLARD BRANCH NR FAIRFIELD CA (FMB)
The list above shows the 14 stations used by the Continuous Water Quality Monitoring Network. Station names are linked to the USGS National Water Dashboard web page for that station. The Water Dashboard provides the parameters monitored at each station as well as past data.
Relevance and benefits
Operation of the Continuous Water Quality Monitoring Network is directly related to drinking water supplies for two-thirds of the State of California’s population and irrigation water for California’s multi-billion-dollar agricultural industry. This monitoring network also addresses the ecosystem and climate strategic directions in the USGS Science Plan. This is accomplished by improving our understanding of the effects upon and changes in the water quality in the Sacramento-San Joaquin Delta. This is especially important during drought and other unanticipated, short-lived, or rapidly changing conditions.
The Monitoring Network provides relevant information based on the collection and analysis of flow and water quality data collected concurrently across the entire Sacramento-San Joaquin Delta landscape. These data are are routinely used by the US Bureau of Reclamation, US Fish and Wildlife Service, National Oceanic and Atmospheric Administration (NOAA) and others State and Federal agencies.
Water quality in Northern California’s Sacramento-San Joaquin Delta (Delta) is essential to clean drinking water, agricultural activities, and the health of the aquatic food web. Management of this important water resource requires the strategic collection of relevant and timely data. A primary component of this data collection is measuring and monitoring water quality.
USGS monitoring stations have been collecting water quality and flow data in the Delta for almost half a century but parameters have been largely limited to temperature, salinity, and turbidity. In recent years, this work has expanded at several locations to include nutrient measurements and other biologically important water quality parameters (dissolved oxygen, pH, chlorophyll, and dissolved organic matter). In addition, new methods have been developed that use these data to assess habitat quality, productivity, and biogeochemical rates.
The enhanced water quality stations identified in this project are often co-located with hydrodynamic measurements like water stage and flow (velocity, discharge and direction). The value of enhanced water-quality and nutrient measurements at flow stations across the Delta allows for a direct comparison of constituent flux across seasons and water years. The high frequency, real-time data collected at monitoring stations also serve as an early warning system for unanticipated, short-lived, or rapidly changing conditions, such as those due to spills, harmful algal blooms, and altered water-quality resulting from storms or levee breaches.
The characteristics being measured fall into the following categories:
I. Core water-quality data
Core water-quality data parameters include 1] temperature, 2] specific conductance (salinity), and 3] turbidity (sediment), all of which drive biological and ecosystem processes.
Salinity as an indicator of conductance
Fresh water from California rivers mixes with salt water from the Pacific Ocean. This mixing is affected by tides, waves, wind, and freshwater inflow. Salinity, or the saltiness in a body of water, is the main factor in determining conductance. Specific conductance is the measurement that is temperature compensated.
Along with water temperature, identifying gradients of salinity, or specific conductance, is key to understanding changes in an ecosystem as well a significant water management concern.
Turbidity and sediment
Sediment suspended in the water column causes turbidity, which in turn affects light penetration, ecological productivity, and habitat quality.
Sediment from watersheds is delivered downstream and is deposited along the Delta’s shores and tidal wetlands. This process helps maintain wetlands and protects against coastal erosion and the effects of sea-level rise. Sediment also plays a crucial role in the preservation of habitat for wildlife.
The collection of turbidity data is critical in quantifying suspended sediment and its distribution to existing and planned marsh habitats. One example is that turbidity data is used in the creation of numerical models.
II & III. Enhanced water-quality data and Nutrients
Enhanced water-quality data include levels of dissolved oxygen, pH, chlorophyll, dissolved organic carbon, and nutrients that impact aquatic biogeochemical processes. Together with hydrodynamic and core water-quality data, these parameters can favor different species, can determine the health of the food web, and can impact the suitability of water for different uses.
Overview of parameters measured at water quality monitoring stations
The network
The USGS high-resolution (15 minute) fixed monitoring network in the Delta includes over 40 flow stations that are often co-located with ‘core water quality’ . Approximately 14 of these stations include enhanced-water quality monitoring activities maintained by the California Water Science Center (CAWSC) Biogeochemistry Group.
Station name (Abbreviation)
- SACRAMENTO R A FREEPORT CA (FPT)
- SACRAMENTO R AB DELTA CROSS CHANNEL CA (WGA)
- CACHE SLOUGH AB RYER ISLAND FERRY NR RIO VISTA CA (CCH)
- CACHE SLOUGH A S LIBERTY ISLAND NR RIO VISTA CA (LIB)
- TOE DRAIN A LIBERTY ISLAND NR COURTLAND CA (TOW)
- SAN JOAQUIN R A JERSEY POINT CA (JPT)
- SACRAMENTO R DEEP WATER SHIP CHANNEL NR COURTLAND (DWS)
- SACRAMENTO R DEEP WATER SHIP CHANNEL NR FREEPORT (DWF)
- SACRAMENTO R BL TOLAND LANDING NR RIO VISTA CA (TOL)
- SUISUN BAY A VAN SICKLE ISLAND NR PITTSBURG CA (CFL)
- GRIZZLY BAY A SUISUN SLOUGH NR AVON CA (GRZ)
- MIDDLE R AT MIDDLE RIVER CA (MDM)
- LITTLE POTATO SLOUGH A TERMINOUS CA (LPS)
- FIRST MALLARD BRANCH NR FAIRFIELD CA (FMB)
The list above shows the 14 stations used by the Continuous Water Quality Monitoring Network. Station names are linked to the USGS National Water Dashboard web page for that station. The Water Dashboard provides the parameters monitored at each station as well as past data.
Relevance and benefits
Operation of the Continuous Water Quality Monitoring Network is directly related to drinking water supplies for two-thirds of the State of California’s population and irrigation water for California’s multi-billion-dollar agricultural industry. This monitoring network also addresses the ecosystem and climate strategic directions in the USGS Science Plan. This is accomplished by improving our understanding of the effects upon and changes in the water quality in the Sacramento-San Joaquin Delta. This is especially important during drought and other unanticipated, short-lived, or rapidly changing conditions.
The Monitoring Network provides relevant information based on the collection and analysis of flow and water quality data collected concurrently across the entire Sacramento-San Joaquin Delta landscape. These data are are routinely used by the US Bureau of Reclamation, US Fish and Wildlife Service, National Oceanic and Atmospheric Administration (NOAA) and others State and Federal agencies.