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Surface Water

Streams, rivers, lakes and reservoirs - collectively referred to as surface water - are important natural resources for irrigation, public supply, wetlands and wildlife. Surface water is also measured as annual runoff, which is the amount of rain and snowmelt drainage left after the demands of nature, evaporation from land, and transpiration from vegetation have been supplied. It supplies most of our basic water needs.

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Rock Drought Barrier on West False River

Emergency Drought Barrier’s Impacts on cyanoHABs and Water Quality

Drought is making the Delta Saltier. Less freshwater coming from watershed runoff and reservoir releases means that more salty water flows into the Sacramento San Joaquin Delta (Delta) from the Pacific Ocean. Changes in Delta salinity have far-reaching impacts, affecting the water supply for agriculture, drinking, wildlife, and Delta ecosystems.
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California Water Science Center
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Emergency Drought Barrier’s Impacts on cyanoHABs and Water Quality

Drought is making the Delta Saltier. Less freshwater coming from watershed runoff and reservoir releases means that more salty water flows into the Sacramento San Joaquin Delta (Delta) from the Pacific Ocean. Changes in Delta salinity have far-reaching impacts, affecting the water supply for agriculture, drinking, wildlife, and Delta ecosystems.
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Research boat next to a dock at Clear lake, CA

Hydrologic and Aquatic Ecology Studies at Clear Lake, California

The USGS California Water Science Center conducts a variety of research activities at Clear Lake, California, including surface-water monitoring and water quality and aquatic habitat studies.
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California Water Science Center
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Hydrologic and Aquatic Ecology Studies at Clear Lake, California

The USGS California Water Science Center conducts a variety of research activities at Clear Lake, California, including surface-water monitoring and water quality and aquatic habitat studies.
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areal view of the Klamath River, Iron Gate Dam and Hatchery. A portion of the Iron Gate Reservoir can be seen to the right.

Klamath Dam Removal Studies

Following the removal of four dams along the Klamath River, more naturally dynamic flow conditions may result in novel water quality, sediment transport, and geomorphic conditions leading to temporary or longer-term ecological impacts. USGS continuous and discrete monitoring data on aspects related to sediment and geomorphic conditions will be integral to post-dam removal assessments and...
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California Water Science Center, Oregon Water Science Center, Pacific Coastal and Marine Science Center, Western Geographic Science Center
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Klamath Dam Removal Studies

Following the removal of four dams along the Klamath River, more naturally dynamic flow conditions may result in novel water quality, sediment transport, and geomorphic conditions leading to temporary or longer-term ecological impacts. USGS continuous and discrete monitoring data on aspects related to sediment and geomorphic conditions will be integral to post-dam removal assessments and...
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Delta wetland near Rio Vista, California.

Delta Wetlands and Resilience: Blue Carbon and Marsh Accretion

Blue carbon ecosystems (BCEs) are coastal ecosystems, such as tidal marshes, mangroves, and seagrasses, with manageable and atmospherically significant carbon stocks and fluxes. The tidal marshes and scrub-shrub wetlands in the Sacramento-San Joaquin Delta (Delta) of California are examples of BCEs. The Delta is a 2,400 square kilometer tidal freshwater region located at the landward end of the...
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California Water Science Center
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Delta Wetlands and Resilience: Blue Carbon and Marsh Accretion

Blue carbon ecosystems (BCEs) are coastal ecosystems, such as tidal marshes, mangroves, and seagrasses, with manageable and atmospherically significant carbon stocks and fluxes. The tidal marshes and scrub-shrub wetlands in the Sacramento-San Joaquin Delta (Delta) of California are examples of BCEs. The Delta is a 2,400 square kilometer tidal freshwater region located at the landward end of the...
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Image: Microcystis aeruginosa Microscopic View

Identifying the Source and Taxa That are Producing Microcystins Detected in San Francisco Bay

Microcystins are toxins produced by cyanobacteria (previously known as blue-green algae ) that are harmful to humans and other animals. In 2012, microcystins began to be detected in San Francisco Bay (SFB). This was unexpected because most microcystin producing cyanobacteria live in freshwater. On-going microcystin-related work has focused on monitoring the presence of microcystins in water and...
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California Water Science Center
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Identifying the Source and Taxa That are Producing Microcystins Detected in San Francisco Bay

Microcystins are toxins produced by cyanobacteria (previously known as blue-green algae ) that are harmful to humans and other animals. In 2012, microcystins began to be detected in San Francisco Bay (SFB). This was unexpected because most microcystin producing cyanobacteria live in freshwater. On-going microcystin-related work has focused on monitoring the presence of microcystins in water and...
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LoRa-cellular gateway with EnviSense data logger/transmitter

Monitoring Drought Conditions in the Upper Feather River Watershed

The Upper Feather River Watershed is one of California’s regions of highest precipitation. Its runoff provides the majority of water delivered by the State Water Project, an average 3.2 million-acre feet each year feeding into Lake Oroville.
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California Water Science Center, National Innovation Center
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Monitoring Drought Conditions in the Upper Feather River Watershed

The Upper Feather River Watershed is one of California’s regions of highest precipitation. Its runoff provides the majority of water delivered by the State Water Project, an average 3.2 million-acre feet each year feeding into Lake Oroville.
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All-American Canal winding through the Imperial Sand Dunes

Forecasting Total Dissolved Solids Concentrations of Groundwater from the Lower Colorado Water Supply Project

The USGS seeks to increase understanding of the groundwater system in the vicinity of the Lower Colorado Water Supply Project well field and to estimate future groundwater levels and total dissolved solids concentrations in the wells and the long-term viability of the Lower Colorado Water Supply Project.
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Arizona Water Science Center, California Water Science Center
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Forecasting Total Dissolved Solids Concentrations of Groundwater from the Lower Colorado Water Supply Project

The USGS seeks to increase understanding of the groundwater system in the vicinity of the Lower Colorado Water Supply Project well field and to estimate future groundwater levels and total dissolved solids concentrations in the wells and the long-term viability of the Lower Colorado Water Supply Project.
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drifter with high-precision receiver to capture flow speeds

Evaluation of Hydrodynamic Mixing in Keswick Reservoir, California

Keswick Reservoir, on the Sacramento River, receives both water and contaminants from the Spring Creek Debris Dam. The term contaminants refers here to different kinds of chemicals that are in some instances delivered to lakes and rivers. These chemicals can have a detrimental effect on drinking water supplies and the health of humans, fish, and other aquatic species.
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California Water Science Center
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Evaluation of Hydrodynamic Mixing in Keswick Reservoir, California

Keswick Reservoir, on the Sacramento River, receives both water and contaminants from the Spring Creek Debris Dam. The term contaminants refers here to different kinds of chemicals that are in some instances delivered to lakes and rivers. These chemicals can have a detrimental effect on drinking water supplies and the health of humans, fish, and other aquatic species.
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Lake Oroville showing extremely low water under the Enterprise Bridge during 2021 drought.

California Drought

The USGS closely monitors the effects of drought through data collection and research. USGS science supports water managers in preparing for possible future drought by providing information that takes into account long-term hydrologic, climatic, and environmental changes. These studies support successful planning and science-based decision-making by water managers who must address complex issues...
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California Water Science Center, Land Subsidence in California
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California Drought

The USGS closely monitors the effects of drought through data collection and research. USGS science supports water managers in preparing for possible future drought by providing information that takes into account long-term hydrologic, climatic, and environmental changes. These studies support successful planning and science-based decision-making by water managers who must address complex issues...
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a photo of two milky-colored desert pupfish against a dark background

Investigation of Groundwater and Surface Water Interactions in Support of Ecosystem Management at San Sebastian Marsh, California

To help the U.S. Bureau of Land Management determine the long-term sustainability of the San Sebastian Marsh, and its critical role for the survival of the endangered desert pupfish (Cyprinodon macularius), the USGS is evaluating the potential interactions and relation between groundwater and surface water at the San Sebastian Marsh.
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California Water Science Center
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Investigation of Groundwater and Surface Water Interactions in Support of Ecosystem Management at San Sebastian Marsh, California

To help the U.S. Bureau of Land Management determine the long-term sustainability of the San Sebastian Marsh, and its critical role for the survival of the endangered desert pupfish (Cyprinodon macularius), the USGS is evaluating the potential interactions and relation between groundwater and surface water at the San Sebastian Marsh.
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concrete-lined river running through an industrial area

Continuous, Water-Quality Monitoring of the Los Angeles River

As part of the Urban Waters Federal Partnership (UWFP) program, this project will bring enhanced water-quality monitoring to a stretch of the Los Angeles River slated for revitalization. The UWFP reconnects urban communities—particularly those that are overburdened or economically distressed—with their waterways by improving coordination among federal agencies.
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California Water Science Center
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Continuous, Water-Quality Monitoring of the Los Angeles River

As part of the Urban Waters Federal Partnership (UWFP) program, this project will bring enhanced water-quality monitoring to a stretch of the Los Angeles River slated for revitalization. The UWFP reconnects urban communities—particularly those that are overburdened or economically distressed—with their waterways by improving coordination among federal agencies.
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Side-looking acoustic Doppler velocity meter and water quality sonde

State of the Network: Long-Term, High-Frequency Flow and Water Quality Data in the San Francisco Estuary, California

The San Francisco Bay and Sacramento-San Joaquin Delta form one of the largest estuaries in the United States. Water flow and water quality in the San Francisco Bay-Delta Estuary are important to the economies of both California and the nation. The Bay-Delta system provides water to more than 25 million California residents and vast farmlands, as well as key habitat for birds, fish, and other...
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California Water Science Center
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State of the Network: Long-Term, High-Frequency Flow and Water Quality Data in the San Francisco Estuary, California

The San Francisco Bay and Sacramento-San Joaquin Delta form one of the largest estuaries in the United States. Water flow and water quality in the San Francisco Bay-Delta Estuary are important to the economies of both California and the nation. The Bay-Delta system provides water to more than 25 million California residents and vast farmlands, as well as key habitat for birds, fish, and other...
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