Surface Water Quality
Surface Water Quality
California's rivers and streams are a priceless resource. To understand the value of water quality, and to more effectively manage and protect the state's water resources, it's critical that we know the current status of water-quality conditions, and how and why those conditions have been changing over time. At the California Water Science Center, measuring the quality of surface water is one of the chief aims of its hydrological monitoring efforts.
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Atmospheric Deposition Contributions to Mercury Yields in Select Watersheds in the Western United States and Canada
The atmosphere plays an important role in the delivery to and cycling of mercury (Hg) in the environment and it can be a major source of Hg contamination to surface waters. Globally, atmospheric deposition of Hg is the primary source of Hg related concerns for human and ecosystem health (Fitzgerald and others, 1998). In California and other areas in the United States, Hg use in gold and silver...
Perchlorate Source Attribution Study in Zones 1-4 of the Stringfellow Superfund Site, Jurupa Valley, Riverside County, California
Between 1956 and 1972, the Stringfellow Hazardous Waste Site, Riverside County, Calif., discharged approximately 34 million gallons of industrial wastes to unlined surface impoundments located at the head of Pyrite Canyon. Contaminants from the site have been detected as far as 4 miles downgradient near the Santa Ana River. Perchlorate in excess of the California Maximum Contaminant Level of 6...
Monitoring Mercury and Methylmercury in Water, Sediment and Biota in Combie Reservoir Before and After Dredging and Mercury Removal
Dredging to maintain water storage capacity by the Nevada Irrigation District (NID) occurred at Lake Combie reservoir, one of several reservoirs along the Bear River, California over the past 40 years on an as-needed basis to maintain water storage capacity. Maintenance dredging operations were halted by the Central Valley Regional Water Quality Control Board (CVRWQCB) in 2002 because of elevated...
Sediment supply, salt marsh monitoring, and the carbon budget of Humboldt Bay, CA
Suspended-sediment measurements are essential for coastal planning, resource management, and for assessing the sustainability of salt marshes in relation to expected sea-level rise. Suspended sediment can have positive or negative effects, depending on its characteristics and amount, and on the location and ecosystem services of interest. Sediment deposition in salt marshes helps sustain marsh...
Lower American River Mercury
Dredging operations for gold along the American River began in the 1860s and continued through the early part of the 20th century, ending about 1962. More than one billion cubic yards of gravel were dredged, making the American River dredge field the second largest in California.
Implementing New Acoustic Monitoring Techniques in the Trinity River
Accurate river-sediment data is fundamental to planning and managing river restoration efforts on the Trinity River, and throughout the world’s waterways. The USGS has developed a “hydrophone” that enables scientists to listen to sediment particles as they move along the riverbed in order to inexpensively and reliably record near-continuous sediment-bedload-transport data. For this study...
Pesticide Fate Research Group (PFRG)
Pesticides are used in both agricultural and urban settings to manage unwanted plants, insects, fungi, and other pests. However, these substances and their breakdown products can move beyond their intended application sites through various means, ending up in areas where they weren't meant to be. This movement can happen via the air, through water (both surface and groundwater), and by sticking to...
Low Intensity Chemical Dosing (LICD)
Rivers, wetlands, and agricultural operations supply natural organic material to the Sacramento-San Joaquin Delta (Delta) and the San Francisco Estuary. This natural organic matter provides many ecosystem benefits, but it also adversely affects drinking water. During drinking water treatment, chlorine added for purposes of pathogen control reacts with dissolved organic carbon (DOC) in the water to...
Assessing Deposit Build-up in Corte Madera Flood Control Channel
The Corte Madera Flood Control Channel was designed to prevent waters from overflowing Corte Madera Creek in a highly populated area of Marin County. Since the channel was last dredged in 1990 approximately 5,400 cubic feet of sediment has accumulated. The accumulation of sediment is of concern because the sediment may reduce the effectiveness of the channel, posing a flooding threat to...
Ground-Water Nitrate and Organic Carbon Inputs to the Lower San Joaquin River
This proposal addresses drinking water and aquatic habitat issues associated with nitrate and organic carbon in the lower San Joaquin River (SJR).
Analysis of Factors Causing Mercury Impairment in Water Bodies of the Sierra Nevada, California
The SWRCB has requested assistance from the USGS in analyzing the factors that control Hg concentrations in fish tissue in the Sierra Nevada. Specifically, the SWRCB wants to know whether Hg and (or) MeHg in bed sediment and (or) suspended sediment could be potentially useful in the future as a 303(d) listing criteria. The SWRCB has requested that the USGS perform an analysis of existing data for...
Improved Monitoring of Water Quality and Pelagic Organism Decline in the Delta with Continuous In Situ Sensor Measurements
Newly-developed, commercially-available sensors permit real-time collection of water quality data that may help identify ecosystem processes that affect the health of pelagic food webs in the Sacramento – San Joaquin Delta. In particular, the simultaneous measurement of nutrients, organic matter and algal abundance along with the basic water quality variables such as temperature and salinity -...