GOLDEN, Colo., April 21, 2014 – Colorado School of Mines research on the impact on watersheds by the mountain pine beetle infestation has been published by the journal Nature Climate Change.

The study, "Hydrological effects of forest transpiration loss in bark beetle-impacted watersheds," was led by Mines PhD student Lindsay Bearup and co-authored by Reed Maxwell, professor in the Geology and Geological Engineering Department, David Clow of the USGS Colorado Water Science Center, and John McCray, head of Mines’ Department of Civil and Environmental Engineering.

The paper investigates how widespread tree death can change the hydrologic cycle in watersheds that have been devastated by the mountain pine beetle.

“While we couldn't predict when the beetles would hit our field sites in Rocky Mountain National Park, we were lucky that a similar study had been done before the beetles hit. Using ‘fingerprints’ of different water sources defined by water chemistry and stable isotopes, we found that a higher fraction of late-summer streamflow comes from groundwater in impacted watersheds,” said Bearup.

Bearup explained that the magnitude of increased groundwater contributions was also consistent with expected loss of transpiration as trees are killed, compared to using more traditional estimates of transpiration.

Maxwell added, “With the millions of dead trees, we asked what is the potential impact if they stop using water? Well, our findings identify this change and quantify how much water trees use, a really fundamental question.”

Bearup also noted that the greater implication of this work is that the changing flow paths of water to the stream can alter water quality. This new finding helps explain earlier work by Mines researchers in 2013, which found an unexpected spike of carcinogenic disinfection byproducts in late-summer in water treatment plant data from infested watersheds.

Contact:

Karen Gilbert, Director of Public Relations, Colorado School of Mines / 303-273-3541 / kgilbert@mines.edu
Kathleen Morton, Communications Coordinator, Colorado School of Mines / 303-273-3088 / kmorton@mines.edu