Although record low precipitation has been the main driver of one of the worst droughts in California history, abnormally high temperatures have also played an important role in amplifying its adverse effects, according to a recent study by the U.S. Geological Survey and university partners.

A piece of the restoration puzzle to save populations of endangered freshwater mussels may have been found, according to a recent U.S. Geological Survey led study. Local population losses in a river may not result in irreversible loss of mussel species; other mussels from within the same river could be used as sources to restore…

More than 1,000 dams have been removed across the United States because of safety concerns, sediment buildup, inefficiency or having otherwise outlived usefulness. A paper published today in Science finds that rivers are resilient and respond relatively quickly after a dam is removed. “The apparent success of dam removal as a means of river restoration is reflected in the…

A team of scientists led by the U.S. Geological Survey found that polar bears, increasingly forced on shore due to sea ice loss, may be eating terrestrial foods including berries, birds and eggs, but any nutritional gains are limited to a few individuals and likely cannot compensate for lost opportunities to consume their traditional, lipid-rich…

In a long-term field study, U.S. Geological Survey (USGS) and Virginia Tech scientists have found that changes in geochemistry from the natural breakdown of petroleum hydrocarbons underground can promote the chemical release (mobilization) of naturally occurring arsenic into groundwater. This geochemical change can result in potentially significant arsenic groundwater contamination. 

Average chloride concentrations often exceed toxic levels in many northern United States streams due to the use of salt to deice winter pavement, and the frequency of these occurrences nearly doubled in two decades. Chloride levels increased substantially in 84 percent of urban streams analyzed, according to a U.S. Geological Survey study that began as early as…

In a new polar bear study published today, scientists from the United States and Canada found that during the first decade of the 21st century, the number of polar bears in the southern Beaufort Sea experienced a sharp decline of approximately 40 percent. The scientists, led by researchers at the U.S. Geological Survey, found that survival of adult bears…

A recent U.S. Geological Survey estimates that the Pacific walrus population nearly halved between 1981 and 1999, the last year for which demographic data are available. The study notes that the decline was most severe in the mid-1980s, and then moderated in the 1990s. Currently, the USGS is working to obtain more recent population data…

Scientists have discovered that the rapid spread of hybridization between a native species and an invasive species of trout in the wild is strongly linked to changes in climate. In the study, stream temperature warming over the past several decades and decreases in spring flow over the same time period contributed to the spread of…

Rivers throughout middle Tennessee crested at record high levels last week. They exceeded previous highs at many streamgages by as much as 14 feet, according to preliminary estimates released today by the U.S. Geological Survey (USGS). The highest flood levels were recorded on May 2 and 3, from Nashville west toward Jackson, extending about 40-miles…