After a Wildfire, the Erosion Problem Begins

Aug 23, 2012

Fire bosses say a blaze in central Washington is 90 percent contained. That’s while large fires continue to burn in Idaho and California. Getting these wildfires under control marks the beginning of a new problem: soil erosion.

Extreme heat from wildfires destroys trees and ground cover. That means plants no longer keep soil from sliding down hillsides and into streams.

Residents near the Taylor Bridge Wildfire could see more sediment on roads and in creeks. They also might notice wind kicking up extra dust.

Anna Lael works with the Kittitas County Conservation District. She says people are starting to confront the problems soil erosion could cause.

“Undoubtedly soil erosion is a big concern, here, in the areas that burned. The degree to which it’s a concern, we don’t know yet until we’re able to go in and do some assessments.”

Landscape plays a big role in how much soil erodes. Steep slopes and severely burned areas are more likely to face threats.

Bill Elliot studies soil erosion and wildfires with the U.S. Forest Service. He says sandy soils erode the most after a fire. The soil in Kittitas County is covered in volcanic ash. Elliot says that means fewer problems.

 “They’re gonna see elevated amounts of runoff for a couple of years, two or three years, until the vegetation establishes.”

Extra runoff can make streams flood more easily. Elliot says the runoff could also cause problems for salmon.

The most effective way to prevent erosion, Elliot says, is to cover the soil with straw or shredded wood. Another step is to reseed grass as soon as possible.

Large wildfires are also burning in Idaho. Fire officials say soil erosion is often a big problem in the state. That’s because Idaho already has naturally shallow soil with steep slopes.

Bill Elliot says the Pacific Northwest has a good climate for fire recovery: fewer large downpours and more drizzly days.

 “Pray for drizzles, not for storms. That kind of a thing. That’s what really helps these sites recover. The slow rains soak up the soils. You get very little runoff so it doesn’t mess up your creek systems, and so on.”

Right now, Anna Lael says, Kittitas County, in central Washington, is working to come up with a plan to prevent soil erosion.

Copyright Northwest News Network 2012