California Water Science Center
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.
Browse Surface Water science related to:
Sediment transport, streamflow, and climate change: long-term resilience of the Bay-Delta
Sediment supply is important to the health of the Sacramento-San Joaquin River Delta and San Francisco Bay (Bay-Delta) ecosystem. Sediment eroded from upland source areas in the Sacramento and San Joaquin watersheds is transported through the rivers to the Bay-Delta where it is deposited in mudflats and tidal wetlands, which in turn helps protect against the effects of sea-level rise. Sediment...
High Resolution Temporal and Spatial Mapping of Mercury and Methylmercury in Surface Waters of the Sacramento – San Joaquin Delta
Mercury (Hg) is a contaminant of significant concern in the San Francisco Bay-Delta estuary and watershed (Bay-Delta). The formation, fate, and transport of methylmercury (MeHg), a particularly toxic organic form of Hg that readily bioaccumulates in wildlife, has been studied extensively throughout the system. However, there is widespread recognition of the need for more comprehensive...
Evaluating the effects of wastewater-derived nutrients on phytoplankton abundance and community structure in the San Francisco Estuary and Delta
Planned upgrades to the Sacramento Regional wastewater treatment plant (SRWTP) will substantially reduce nutrient discharge and also alter the types and amounts of nutrients being distributed across the San Francisco Delta and Estuary (Delta).
One highly anticipated outcome of lower nutrients is improved productivity in the phytoplankton communities that supply aquatic food webs, which...
Modeling Nitrogen Reduction Benefit to Invasive Aquatic Vegetation vs. Native Phytoplankton
Phytoplankton comprise the bottom of the aquatic food web and the abundance of phytoplankton serves as an indicator of healthy aquatic habitats. In the Sacramento-San Joaquin River Delta (Delta), competing with phytoplankton for required nitrogen, invasive aquatic vegetation (IAV) has increased exponentially in recent years. Once established, IAV can negatively impact local ecosystems and...
Monitoring Cyanotoxins in California's Sacramento-San Joaquin Delta: Fixed Stations and High-Resolution Mapping Surveys
California’s Sacramento-San Joaquin River Delta (Delta) provides drinking water to about 30 million people and irrigation water to the agriculturally rich Central Valley. The Delta is also home to numerous threatened and endangered native species. The health of the Delta's aquatic ecosystems, and fish in particular, have long been in a state of decline. This is associated with decreasing...
Effects of Wildfire and Fire Retardants on Nutrient Transport in California Watersheds
Large wildfires have increased in size and frequency in the western United States over the past several decades. This has led to increased soil erosion and the transport of sediment containing nutrients into streams and reservoirs. Excess nutrients typically lead to the increased production of algae which can then lead to low levels of dissolved oxygen. This degrades the habitat for fish and...
Mercury studies at Sulphur Bank Mercury Mine and Clear Lake, California
The abandoned Sulphur Bank Mercury Mine on the shores of Clear Lake in Northern California has been designated as a "Superfund Site" by the U.S. Environmental Protection Agency (EPA). This means that the EPA has determined that the area is contaminated by hazardous waste and requires cleanup...
Organic Matter Research Laboratory
The USGS California Water Science Center's Organic Matter Research Laboratory provides laboratory services and support to regional and national projects in the analysis of organic matter using the latest methods in absorbance and fluorescence spectroscopy along with standard measurement of total dissolved organic carbon and nitrogen concentration.
Improving Forecasting for California's Snow Melt Water Supply
California's Sierra Nevada snowpack accounts for much of the water supply in many parts of the state. The snowpack retains large amounts of water in the winter that is then released as temperatures rise in the spring and summer. The snowpack also keeps the Sierra soil moist by covering it longer into spring and summer. Soil moisture influences the onset of wildfires, as well as wildfire...
Channel Complexity Synthesis - Trinity River Restoration Program
The Trinity River Restoration Program implements the Department of Interior directive to restore the fisheries of the Trinity River impacted by dam construction and related diversions. The multi-agency program is one of the nation’s largest adaptively managed river restoration efforts and requires periodic assessment to determine its effectiveness in restoring channel dynamics and habitat...
Klamath River Geomorphic Assessment
The Klamath River is the third largest river flowing into the Pacific Ocean from the continental U.S. The headwaters of the Klamath are located in the Cascade Range in southeastern Oregon and the river flows through northern California to its estuary. Beginning in the 1860s, the flow and water quality of the Klamath started to change due to the building of dams and other water diversions for...
Developing Spatial Data on Mineral Deposits Found on Abandoned Mine Lands
Better understanding of mineral deposits and their impact on the environment, including the water system, is necessary for the protection of public health. The USGS is working with other federal and state agencies to identify the environmental behavior of these deposits and their waste products. USGS scientists are using geospatial data (data that can be mapped) to prioritize abandoned mine...