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:
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.
Continuous, Real-Time 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...
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...
Scotts Creek Nutrient Erosion Study, Lake County, California
Clear Lake, the largest natural lake entirely within California, has a severe problem with harmful algal blooms which can be detrimental to aquatic life by depriving it of oxygen when the algae dies, sinks, and decays. A driving factor of these conditions are the nutrient loads being carried into the lake by soil erosion and...
Assessing Sediment Nutrient Storage and Release in California's Sacramento-San Joaquin Delta
Sediments represent an important pool of nutrients in the Sacramento-San Joaquin Delta (Delta). The exchange of nutrients between the water column and the benthos impacts water quality and effects phytoplankton, harmful algal blooms, aquatic vegetation, and drinking water quality. To date, there is very limited information about nutrient pools in Delta sediments, nor how these nutrients are...
Ecosystem Engineering Impacts of Water Primrose in the Sacramento-San Joaquin Delta
Many non-native fish, invertebrates, and plants have colonized the Sacramento-San Joaquin Delta (Delta) of California, the landward most region of the San Francisco Estuary. Included among these invasive species is the water primrose (Ludwigia spp.), an aggressive floating aquatic plant that is native to South and Central America and parts of the US, but invasive in California. Water primrose...
Selenium Hazard in the Salton Sea Environment, Summary of Current Knowledge to Inform Future Science
The effect of selenium (Se) toxicity on wildlife has been known for more than 50 years. The threat of Se contamination gained greater attention from federal agencies in the 1980s due to the observation of embryo deformity and mortality in birds at a National Wildlife Refuge in California. Harmful effects from Se were determined to be connected to irrigation drainage water.
As a result,...
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...