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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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a picture of a flooded road in San Diego, CA

About Floods

To help emergency managers and others protect life and property due to floods and other water-related hazards, the USGS delivers a continuous source of streamflow information. The USGS California Water Science Center maintains nearly 500 streamgages that collect data to determine the amount of water flowing in rivers and streams, and in and out of reservoirs, in California. Automatic alerts are...
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California Water Science Center
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About Floods

To help emergency managers and others protect life and property due to floods and other water-related hazards, the USGS delivers a continuous source of streamflow information. The USGS California Water Science Center maintains nearly 500 streamgages that collect data to determine the amount of water flowing in rivers and streams, and in and out of reservoirs, in California. Automatic alerts are...
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Lake Oroville showing extremely low water under the Enterprise Bridge during 2021 drought.

About 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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About 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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charred, bare trees on a mountain side

About Wildfires

Over the last several decades, both the incidence of large wildfires and the duration of the wildfire season across much of the United States have increased (Westerling and others, 2006, American Water Works Assn, 2008; Finco and others, 2012). Future wildfire projections based on forecasted climate scenarios indicate both an increase in the expected severity of wildfires, and an expansion of...
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California Water Science Center, Wildland Fire Science
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About Wildfires

Over the last several decades, both the incidence of large wildfires and the duration of the wildfire season across much of the United States have increased (Westerling and others, 2006, American Water Works Assn, 2008; Finco and others, 2012). Future wildfire projections based on forecasted climate scenarios indicate both an increase in the expected severity of wildfires, and an expansion of...
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concrete-lined river running through an industrial area

Water-Quality Monitoring in the Sepulveda Flood Control Basin of the Los Angeles River Watershed

As part of the Urban Waters Federal Partnership (UWFP), this project will enhance water-quality monitoring on a reach 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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Water-Quality Monitoring in the Sepulveda Flood Control Basin of the Los Angeles River Watershed

As part of the Urban Waters Federal Partnership (UWFP), this project will enhance water-quality monitoring on a reach 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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Drain carrying runoff from farm fields in Imperial Valley

Selenium Cycling in Salton Sea Wetlands

The effect of selenium toxicity on wildlife has been known for more than 50 years. This issue drew particular attention in the 1980s when embryo deformity and mortality was observed in birds at a wildlife refuge in California. Harmful effects from selenium were determined to be connected to irrigation drainage water. As a result, an effort began to monitor levels of selenium in irrigation drainage...
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California Water Science Center, Western Ecological Research Center (WERC)
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Selenium Cycling in Salton Sea Wetlands

The effect of selenium toxicity on wildlife has been known for more than 50 years. This issue drew particular attention in the 1980s when embryo deformity and mortality was observed in birds at a wildlife refuge in California. Harmful effects from selenium were determined to be connected to irrigation drainage water. As a result, an effort began to monitor levels of selenium in irrigation drainage...
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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 and modeling soil moisture to improve runoff forecasting and drought characterization in the Feather River Basin

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 and modeling soil moisture to improve runoff forecasting and drought characterization in the Feather River Basin

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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