Researchers will capture a snapshot in time of water quality from 250 locations within and around Rocky Mountain National Park in order to glimpse how differences in climate, pollution and disturbances like mountain pine beetle are affecting Colorado's watersheds.
On Aug. 12, with the help of more than 70 volunteers, researchers at the National Park Service and the University of Colorado at Boulder's Cooperative Institute for Research in Environmental Sciences, or CIRES, will collect hundreds of stream samples from both sides of the Continental Divide.
"We want to understand how water quality varies spatially in Rocky Mountain National Park and refine our understanding of what's causing these differences," said James McCutchan, a freshwater biologist with CIRES.
Even basic environmental factors like hill slope, vegetation type and bedrock mineral composition affect stream chemistry across Rocky Mountain National Park, said McCutchan. In addition to basic patterns of variability, McCutchan said he expects to see significant differences between watersheds that have been disturbed by either wildfire or mountain pine beetle and watersheds in unaffected areas.
The removal of much of a watershed's natural vegetation by fire reduces the ability of plants to take up nitrogen and other soil nutrients, he said. As a result, rain and snowmelt tend to flush nitrogen directly into the stream channel.
The researchers hope the collaborative effort between NPS and CU-Boulder will help them learn whether beetle-infested watersheds in the national park have similar chemical signatures.
"Nitrogen is a very important nutrient in streams and can alter the growth of photosynthetic organisms," said McCutchan. "Ultimately this affects the whole food chain, including top-level fish like Colorado's threatened greenback cutthroat trout."
Nutrient changes in the park's high-altitude streams also can affect water quality far downstream. The headwaters of the Colorado, St. Vrain and Big Thompson rivers, which supply drinking and irrigation water to Colorado communities, are all found in Rocky Mountain National Park.
While Tuesday's stream sampling effort is intended to provide a one-time snapshot of water quality, researchers hope to eventually develop a long-term monitoring program at several of the stream locations, McCutchan said. CIRES is a joint institute of CU-Boulder and the National Oceanic and Atmospheric Administration.