Water Quality Monitoring
Water Quality Monitoring
The USGS California Water Science Center maintains a network of continuous water-quality monitors across the state which provide near-real-time water-quality data. Continuous water-quality monitors are typically installed at or near existing USGS stream gages or wells. Parameters that are monitored at continuous water-quality sites include water temperature, specific conductance, dissolved oxygen, turbidity, nitrate, chlorophyll, cyanobacteria, fluorescent dissolved organic matter, and pH.
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Coordinated Pesticide Reconnaissance Study of Surface Waters in California
Pesticides are used throughout the State of California in both urban and agricultural settings and are routinely detected in surface water. Each year, new pesticides are introduced to the market and often become detected in surface water. It can take several years or more for routine monitoring programs to acquire the capability to detect new and understudied pesticides of concern because...
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...
Mercury Methylation and Bioaccumulation in the Bear River Watershed
Extensive mercury use during historical gold processing has resulted in widespread mercury contamination and bioaccumulation of methylmercury in watersheds in the northwestern Sierra Nevada (Slotton and others 1997; Alpers and Hunerlach, 2000). A recent USGS report (May and others, 2000) documented the presence of elevated mercury in fish tissues in five reservoirs in the Bear River, Deer Creek...
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...
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...
Effects of Aquatic Vegetation on Water Quality and Residence Time in the Bay-Delta
The spread of invasive aquatic vegetation in the Sacramento-San Joaquin Delta is having a profound impact on the Delta’s natural habitat. The presence of these “aquatic weeds” has been shown to alter water velocity and increase water clarity, posing threats to native fish species, specifically the threatened Delta Smelt. These aquatic plants can also affect the foodweb by altering nutrient...
San Bernardino Optimal Basin Management
The San Bernardino area of southern California has complex water-management issues. As an aid to local water managers, this report provides an integrated analysis of the surface-water and ground-water systems, documents ground-water flow and constrained optimization models, and provides seven examples using the models to better understand and manage water resources of the area. As an aid to...