Bay-Delta Flow & Water Quality Monitoring Network

Background:

Reclamation operates and maintains the Central Valley Project (CVP) for the purposes of navigation and flood control; fish and wildlife mitigation, protection, restoration, and enhancement; agricultural and municipal and industrial water supply; power generation; and recreation. Reclamation’s mission is to perform these functions in an environmentally and economically responsible manner. To carry out this mission, Reclamation requires accurate and reliable data and information on the hydrodynamic, water quality, and biogeochemical properties of the Sacramento-San Joaquin Delta (Delta) and Suisun Bay. Observational environmental data are used for: (i) real-time operation of CVP facilities, (ii) documenting long-term status and trend measures of Delta ecosystem responses to hydrologic conditions, CVP operations and habitat restoration actions, and (iii) calibrating and validating hydrodynamic, sediment transport, biogeochemical, and ecological models.

The data collected from the Bay-Delta flow & water quality monitoring network include:

picture of sediment with text that says Hydrodynamic data

continuous flow (discharge and velocity) and water level data that provides information about transport, mixing processes and water residence times.

picture of water being collected with text that says water quality data

Continuous measurements include temperature, specific conductance, turbidity, dissolved oxygen, pH, chlorophyll, dissolved organic matter, & nutrients influencing biogeochemical processes such as transformation rates, aquatic productivity, & zooplankton growth. Discrete samples for nutrients are also collected for sensor calibration & to analyze additional parameters.

picture of Phytoplankton with text that says Phytoplankton species
composition data

the collection of discrete samples analyzed for phytoplankton enumeration, as well as continuous deployment of multiparameter fluoroprobes that measure pigments of various phytoplankton species. This information helps build understanding of phytoplankton community composition and dynamics that can inform science and management of beneficial and harmful algal blooms.

picture of sediment with text that says Suspended sediment
data

to assess suspended sediment distribution across the region and to transform turbidity data into suspended sediment concentration to compute suspended sediment fluxes for numerical modelin.

What activities are undertaken to maintain the network?

Calibrating, maintaining, and managing data following standard operating procedures consistent with, or exceeding, historic protocols for the network.
Making real-time data publicly available through CDEC and downloaded data available via Reclamation dashboards (please contact BDO for more information).
Developing flow and sediment rating curves, due to previous curves not being publicly accessible. This process will require one to three years of data collection. Until new rating curves are developed and validated, flow and sediment data will remain provisional.
Planning and permitting updates to stations.
Please see additional details in update documents and/or reports below.

Stations included in this monitoring network:

A list of stations and the constituents measured are in Table 1. Information includes the full station name, the CDEC station ID (linked directly to CDEC station page where possible), the coordinates, and the data types for hydrology, water quality, and sediment. For water quality data, categories indicate whether stations measure temperature (Temp), specific conductivity (SpC), and turbidity (Turb); all water quality consituents (All WQ; temperature, specific conductivity, turbidity, pH, dissolved oxygen, chlorophyll a fluorescence, and fluorescence of dissolved organic matter); all water quality and nutrients (Nutr; SUNA nitrate measurements and nutrient sample collection); or all water quality consituents, nutrients, and fluoroprobe measurements. Italicized stations’ infrastructure was destroyed in Summer 2025, so are not currently active.

Table 1.

Station Name	CDEC Station ID	Latitude	Longitude	Flow	Water Quality	Sediment
Sacramento River Deep Water Ship Channel, Channel Marker 51 (CM 51)	C51	38.23739	-121.674	Flow	All WQ	Delta
Sacramento River Deep Water Ship Channel near Courtland (CM 62)	C62	38.34167	-121.644		All WQ + Nutr
Sacramento River Deep Water Ship Channel near Freeport (CM 72)	C72	38.47687	-121.584	Flow	All WQ + Nutr
Channel Marker 49A	CM49A	38.23333	-121.675	Flow	All WQ + Nutr	Delta
Suisun Bay at Van Sickle Island near Pittsburg, CA	CONFL	38.04953	-121.888		All WQ + Nutr + Fluoroprobe
Delta Cross Channel near Walnut Grove, CA	DLC	38.24472	-121.505	Flow	All WQ
Dutch Slough below Jersey Island Road at Jersey Island	DSJ	38.01361	-121.667		Temp + SpC + Turb
False River near Oakley, CA	FAL	38.05583	-121.667	Flow		Delta
Sacramento River below Georgiana Slough, CA	GES	38.23889	-121.522		Temp + SpC + Turb
Grant Line Canal near Tracy, CA	GLC	37.82	-121.545			Delta
Grizzly Bay at Suisun Slough near Avon, CA	GRIZ	38.10853	-122.056		All WQ + Nutr
Georgiana Slough near Sacramento River	GSS	38.23722	-121.518	Flow	Temp + SpC + Turb	Delta
Middle River near Holt, CA	HLT	38.00306	-121.511	Flow		Delta
Holland Cut near Bethel Island, CA	HOL	38.01639	-121.582	Flow		Delta
Cache Slough at Liberty Island near Rio Vista, CA	LIB	38.24222	-121.686	Vel	All WQ + Nutr	Delta
Little Potato Slough at Terminous, CA	LPS	38.09639	-121.496	Flow	All WQ + Nutr
Sacramento River below Toland Landing near Rio Vista, CA (CM 13)	M13	38.07781	-121.767	Vel	All WQ + Nutr + Fluoroprobe
Sacramento River Deep Water Ship Channel near Clarksburg (CM 66)	M66	38.40444	-121.615		All WQ
Middle River at Middle River, CA	MDM	37.94278	-121.533		All WQ + Nutr + Fluoroprobe
Miner Slough near Sacramento River and Prospect Island	MIR	38.23556	-121.666			Delta
Suisun Bay at Mallard Island, CA	MLD	38.04278	-121.919		Temp + SpC + Turb	Bay
Mokelumne River at at Andrus Island near Terminous, CA	MOK	38.10611	-121.571	Flow		Delta
North Mokelumne River near Walnut Grove, CA	NMR	38.22333	-121.507	Flow	Temp + SpC + Turb	Delta
Old River at Bacon Island, CA	OBI	37.97	-121.571		All WQ + Nutr + Fluoroprobe
Old River near Delta Mendota Canal, CA	ODM	37.81056	-121.541			Delta
Old River near Byron, CA	OH4	37.89111	-121.569		Temp + SpC + Turb	Delta
Old River at Quimby Island near Bethel Island, CA	ORQ	38.02722	-121.564	Flow		Delta
Old River at Franks Tract near Terminous, CA	OSJ	38.07111	-121.579	Flow		Delta
San Joaquin River at Prisoner's Point near Terminous, CA	PRI	38.05944	-121.557	Flow		Delta
Cache Slough above Ryer Island Ferry near Rio Vista, CA	RYF	38.19396	-121.658	Flow	All WQ + Nutr	Delta
Sacramento River above Delta Cross Channel, CA	SDC	38.25778	-121.517		All WQ + Nutr
Shag Slough at Liberty Island near Courtland, CA	SGG	38.31833	-121.693	Flow	All WQ + Nutr	Delta
San Joaquin River below Garwood Bridge at Stockton, CA	SJG	37.93556	-121.329	Flow	Temp + SpC + Turb	Delta
San Joaquin River West at Jersey Point, CA	SJW	38.05222	-121.688		All WQ + Nutr + Fluoroprobe	Delta
South Mokelumne River at New Hope Bridge near Walnut Grove, CA	SMR	38.22556	-121.491	Flow	Temp + SpC + Turb	Delta
Sacramento River at Rio Vista, CA	SRV	38.14904	-121.689			Delta
Steamboat Slough near Walnut Grove, CA	SSS	38.28472	-121.587	Flow
Sutter Slough at Courtland, CA	SUT	38.32917	-121.579	Flow
Toe Drain at Mallard Road near Courtland, CA	TOE	38.34917	-121.6447	Flow	All WQ + Nutr	Delta
Turner Cut near Holt, CA	TRN	37.9925	-121.454	Flow		Delta
Threemile Slough near Rio Vista, CA	TSL	38.10333	-121.686			Delta
Victoria Canal near Byron, CA	VCU	37.87083	-121.53	Flow		Delta
Yolo Bypass near Woodland, CA	YBY	38.67778	-121.643		Turb	Delta

Station Map

Figure 1. Map of monitoring stations in this network. Stations either measure flow (discharge and/or velocity; blue points), water quality (WQ; combinations of temperature, specific conductivity, turbidity, dissolved oxygen, pH, chlorophyll a fluorescence, dissolved organic matter fluorescence, nutrients, and phytoplankton pigments; green points), and/or suspended sediment (orange points). Details about specific constituents measured and station abbreviations can be found in Table 1.

Additional information and Links:

Monitoring Network Update, 2/25/26

Delta Science Tracker

Last Updated: 3/11/26

California-Great Basin