PORTLAND, Ore. — Oregon State University has just completed a long-term study that focuses on landslides, how often they happen and how strong they are.
Landslides happen in all 50 states, causing an average of 25 deaths per year, according to the United States Geological Survey.
OSU researchers studied the Lookout Creek Watershed in Western Oregon. Associate Professor in the College of Forestry Catalina Segura said logging and road construction were factors that greatly affected landslides.
"When we cut the trees with the old practices from the fifties and at the same time we get a big storm event, yes we produce a lot of sediment," Segura said.
Segura said the study focused on several different time periods. Logging and road building began in the Lookout Creek Watershed in 1950 and stopped by the 1980s which allowed scientists to start tracking forest management practices.
"If we stop cutting for 20 years and we get a big flood event, we saw less sediment than we did before," Segura said.
Segura said big flooding in 1964 and 1965 when logging was taking place caused much more powerful landslides than the large flood of 1996 more than a decade after logging stopped in Lookout Creek.
"It's not just how much water we get from the clouds that will control how much power we have in the surface but it also depends on how we are managing the condition of the land," Segura said.
Segura said the study was only done on federal lands.