Researchers study link between forest management and drinking water quality
Clemson University researchers will soon begin conducting experiments in four forests across South Carolina to address growing concerns that techniques employed in the fight against wildfires could affect the quality of drinking water.
The team has received $1 million from the U.S. Environmental Protection Agency and $260,048 from the university to figure out which forest management practices are least harmful to drinking water supplies. Team members expect their findings to apply to Southern forests spanning from North Carolina to Texas.
Hanging in the balance is the quality of water that millions of people across country trust to be safe when they turn on their faucets. As part of the study, researchers will try to figure out how to reduce water disinfection byproducts, some of which have been linked to cancer.
The concerns fueling the Clemson research show that while forests are often far from population centers, the way they are managed can have far-reaching effects.
Tanju Karanfil, the principal investigator on the grant, said it is critical that researchers better understand how forest management techniques affect the quality of water sources.
“The research we’re doing will help the country adopt sustainable methods of managing forests, while ensuring that clean, safe drinking water continues to flow to our communities,” Karanfil said. “The need for these kinds of studies will grow as more frequent and intense droughts brought on by climate change cause more wildfires.”
Researchers plan to make the study results available to regulatory agencies, resource managers, counties, planning and public works staffs and other professional decision-makers. A “box model” that researchers plan to develop will provide information that helps water treatment officials manage their watersheds.
Alex Chow, a co-principal investigator, said the team will employ some of the same techniques he has used to study the 2013 Rim Fire, the third largest wildfire in California history.
“It is crucial that we do this research,” said Chow, an associate professor of biogeochemistry and environmental quality in the College of Agriculture, Forestry and Life Sciences.
“We need to find cost-effective ways to reduce forest fires, but we also need to be sure the drinking water is safe. Many questions remain, and we expect this study to help begin providing answers.”
Prescribed burning and mechanical thinning help prevent wildfires, but both techniques likely change the chemical characteristics of drinking water supplies and how they ought to be treated, researchers said.
The study will focus on fallen branches, leaves and other material found on forest floors. That material is the main ignition source for forest fires and the major source of “dissolved organic matter” that flows into drinking water sources when it rains.
Keeping an eye on dissolved organic matter is key for researchers. When water is treated to make it suitable for consumption, the dissolved organic matter combines with disinfectants, such as chlorine, and forms potentially hazardous disinfection byproducts.
The team’s research builds on work that the U.S. Department of Agriculture Forest Service has been doing since 2003 in the Santee Experimental Forest.
“Our preliminary results suggest that although prescribed burning could reduce disinfectant byproduct precursors in source waters, further study is needed to confirm these findings,” Karanfil said.
Researchers will set up experimental plots and watersheds in the Clemson Experimental Forest in Clemson, Francis Marion National Forest near Charleston, Hobcaw Barony near Georgetown and the Tom Yawkey Wildlife Center near Georgetown.
The selection represents longleaf pine and loblolly pine forests of the Piedmont uplands to low-lying coastal ecosystems found across the Southeast.
Weather permitting, burning will take place in 2016 and 2017 on experimental plots at Hobcaw Barony and the Tom Yawkey Wildlife Center. A total of 24 plots will be examined.
As part of the study, researchers will examine the biogeochemical processes that occur as water is conveyed from one place to another. The team is particularly interested in how intensively burnt watersheds can lead to a highly toxic disinfection byproduct, N-nitrosodimethylamine, that has shown to be a probable carcinogen.
For researchers, part of what makes the study unique is how they will characterize the molecular structures of dissolved organic matter. The techniques include the Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, coupled with 13C Nuclear Magnetic Resonance and Pyrolysis Gas Pyrolysis Mass Spectrometry.
“This is a uniquely transformative research program that could change how forests are managed not only in South Carolina, but across the Southeast,” Chow said.