Storms after Wildfire Lead to Impaired Water Quality plus 1 more

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Title: USGS Newsroom

Storms after Wildfire Lead to Impaired Water Quality plus 1 more

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Storms after Wildfire Lead to Impaired Water Quality

Posted: 28 Sep 2015 09:41 AM PDT

Summary: Water quality can be substantially diminished for several years after wildfire in response to relatively common local thunderstorms, according to a recent USGS study

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Contact Information:

Sheila  Murphy ( Phone: 303-541-3023 ); Jon Campbell ( Phone: 703-648-4180 );

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Water quality can be substantially diminished for several years after wildfire in response to relatively common local thunderstorms, according to a recent USGS study. 

USGS scientists led by research hydrologist Sheila Murphy collected extensive streamflow and water-quality data for three years after the Fourmile Canyon Fire, Colo., in a geographic setting typical of the American southwest. They then correlated the results with data from a high-density rain gage network. 

“Unfortunately, wildfires have become a common occurrence in the western United States,” said William Werkheiser, USGS Associate Director for Water. “We need to better understand the drivers of post-wildfire water quality and find ways to adjust to this challenge.” 

About half of the water supply in the southwestern U.S. is supplied by water conveyed from forests, which generally yield higher quality water than any other land use. However, forests are vulnerable to wildfire; more than 12 million acres of land, including important forested water-supply watersheds, have burned in the southwestern U.S. in the past 30 years. Wildfires increase susceptibility of watersheds to both flooding and erosion, and thus can impair water supplies. 

The USGS investigators found that hydrologic and water-quality responses downstream of the burned area were primarily driven by small, brief convective storms that had relatively high, but not unusual, rainfall intensity. Suspended sediment, dissolved organic carbon, nitrate, and manganese concentrations were 10-156 times higher downstream of the burned area compared to upstream, and reached concentrations that could impair the ability of water-treatment plants to effectively treat water for human consumption. 

Results from this study quantitatively demonstrate that water quality can be altered for several years after wildfire, even in a watershed that was only 23% burned. Because wildfire frequency and size, and possibly storm frequency and intensity, are projected to increase in the southwestern U.S. in the future, post-wildfire water-quality impacts may become more common, compounding water supply and quality problems related to projected decreases in runoff and continued population growth. 

Recently published in the journal Environmental Research Letters, the study suggests potential adaptation strategies to avoid the introduction of problematic constituents into water-treatment facilities or reservoirs after wildfire. 

Declines and Slow Recovery in Little Brown Bat Populations Predicted

Posted: 28 Sep 2015 09:30 AM PDT

Summary: Populations of bats diminished by white-nose syndrome (WNS), a disease of hibernating bats, are unlikely to return to healthy levels in the near future, according to new U.S. Geological Survey research

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Highlights Severity of White-Nose Syndrome and Critical Research Needs

Contact Information:

Marisa Lubeck ( Phone: 303-202-4765 ); Gail Moede Rogall ( Phone: 608-270-2438 );

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Populations of bats diminished by white-nose syndrome (WNS), a disease of hibernating bats, are unlikely to return to healthy levels in the near future, according to new U.S. Geological Survey research. 

USGS and U.S. Fish and Wildlife Service scientists recently evaluated the potential for populations of little brown bats in the eastern United States that survive WNS outbreaks to repopulate. The scientists estimated that between 2016 and 2018, little brown bat populations that once contained millions of bats could decrease to lower than 100,000 animals. Also, some populations may not begin to increase again until around 2023. Populations east of the 100^th meridian, the designation between the drier western and wetter eastern states, would likely consist of sparse remnant communities, some of which may be less than 1.5 percent of their original sizes. 

This scarcity of surviving bats can negatively affect reproduction rates and make survivors more vulnerable to threats.

“With so few surviving animals, little brown bats could cease to be a dominant bat species in the eastern United States,” said USGS scientist Robin Russell, the lead author of the report. “These small bat population sizes are problematic because they are more likely to be wiped out by events such as poor weather conditions and landscape development.” 

Animals in small communities could also have trouble finding mates. Female bats gathering in maternity roosts during the summer can include several hundred bats, and the inability to form these colonies due to reduced populations may negatively impact overall reproduction rates. 

Bats pollinate plants, spread seeds and save us billions of dollars in pest control each year by eating harmful insects. WNS, caused by the Pseudogymnoascus destructans fungus, can cause up to 100 percent mortality in some little brown bat populations. It has already killed millions of hibernating bats in North America and continues to spread.

As part of a coordinated response to WNS, scientists from around the world are working to further understand the disease and conserve bat species affected by it. The USGS and USFWS are among numerous state, federal, tribal, private and university partners engaged in WNS research and response. Members of this community are pursuing multiple approaches to manage the disease, with treatment strategies to both reduce impacts of the disease and to improve the potential for bat populations to survive and eventually recover. This new study emphasizes the importance of continuing research on bat species affected by WNS to finding a solution for managing the disease. 

For more information about USGS WNS research, please visit the USGS National Wildlife Health Center website.