Online exclusive: Does Oregon face a dry future?

As a young man growing up in South Korea, Portland State geography professor Heejun Chang never experienced any occupational hesitation.

As a young man growing up in South Korea, Portland State geography professor Heejun Chang never experienced any occupational hesitation. From an early age, Chang knew exactly what it was he wanted to spend the rest of his life doing. He wanted to be a hydro-climatologist.

“My house was at the base of foothills,” he said. “I would always play with the water that would drain off the mountains behind my home. I would run experiments and divert its path with trenches.”

Not much has changed. Nearly 30 years later, Chang is still pursuing his passion.

After receiving his doctorate degree from Penn State University in 2001, Chang was quickly hired by Portland State’s Department of Geography as a professor and researcher.

In November of 2008, Chang was approached by the Oregon Climate Change Research Institute (OCCRI) and asked to lead the freshwater research portion of the Oregon Climate Assessment Report. OCCRI was established in 2007 by the Oregon State Legislature in order to better understand the effects of climate change.

The goal of the report is to create a comprehensive snapshot of Oregon’s changing climate, in order to better understand how the environment will change in 20, 60 and even 80 years from now. The report, containing 10 chapters spanning 400 pages, dedicates at least 80 pages to the research regarding Oregon’s freshwater supply.

In order to collect the data, Chang and his team used downscaled climate change simulation programs, coupled with preexisting research and data on Oregon’s climate background.

“We utilized a precipitation-runoff modeling system,” Chang said. “This is a process-based simulation model that can project what happens in the future by changing the input, which is precipitation and temperature.”

Once these parameters are established, the model can then simulate a projection based on the amounts of carbon dioxide in the atmosphere. The program has the capacity to measure run-off, water elevation and other factors over a given period. Ultimately, the program determines how environmental biomes would behave when temperatures are even slightly changed over decades.

Admittedly, it would be impossible to measure and sample every freshwater source in Oregon and apply the model, according to Chang. To remedy this, he said that certain areas which met various constraints were tested.

“We had to sample areas that were geographically sprawling, such as Tualatin, and also areas with a highly developed urban area, such as the banks of the Willamette River near downtown Portland,” Chang said.

Though Chang’s focus was on the Willamette River basin, personnel from other research entities ran comparable simulations throughout the state. In all, over 100 researchers were involved, including a group from the U.S. Geological Survey.

Though the final research was completed in the summer of 2010, the data was quickly interpreted, compiled and published last month.

“Now we’re looking at this data to try and understand how humans can mitigate some of this environmental change,” Chang said. “The next step is to run a benefit cost analysis. Of course, there is cost involved, but I also believe that there is a much greater benefit.”

Using predictive models, the research found that average annual air temperatures will continue rising at a rate of 0.2–1.0 degrees Fahrenheit per decade, while average precipitation will have decreased 14 percent by the 2080s.

The effects of these changes on the ecosystem are still being investigated.