Logging and landslides: What went wrong?
When Weyerhaeuser began clear-cutting the Douglas firs on the slopes surrounding Little Mill Creek, local water officials were on edge. Some of these lands had slid decades ago, after an earlier round of logging. They worried new slides could dump sediments into the mountain stream and overwhelm a treatment plant. Those fears came true last December.
Seattle Times staff reporters
Video | What went wrong?
What is an "unstable slope"?State forestry rules draw on studies that show logging and road-building can increase the number and size of slides off unstable slopes. The rules say potentially unstable slopes may have some of the following features:
Bedrock hollows of more than 70 percent gradient: These are typically spoon-shaped valleys that are prone to sliding in intense rainstorms. Most are 75 to 200 feet wide at the top and may narrow to 30 to 60 feet downhill. Many have no surface water, but they may contain underground springs.
Convergent headwalls of more than 70 percent gradient: These are areas where two steep slopes come together. They are typically broad at the top and narrow farther downhill.
Inner gorges of more than 70 percent gradient: These are canyonlike formations within a slope. They often show evidence of recent slides, and, if logged, the soils are especially sensitive to a loss of root strength.
Deep-seated landslides: These are areas of weak soils, where the ground previously slid far below the tree roots. The trouble spots could be upslope areas with groundwater seeps and a bottom — or toe — that can be undercut by streams. Road-building and logging can add to the risk of having these areas slide again.
Source: Washington state Forest Practices Board Manual
For more information: www.dnr.wa.gov
BOISTFORT VALLEY, Lewis County — When Weyerhaeuser began clear-cutting the Douglas firs on the slopes surrounding Little Mill Creek, local water officials were on edge.
Some of these lands had slid decades ago, after an earlier round of logging. They worried new slides could dump sediments into the mountain stream and overwhelm a treatment plant.
Those fears came true last December when a monster storm barreled in from the Pacific, drenching the mountains around the Chehalis River basin and touching off hundreds of landslides. Little Mill Creek, filled with mud and debris, turned dark like chocolate syrup.
More than three months passed before nearly 3,000 valley residents could drink from their taps again.
"I have never seen anything like this before, and I hope I never do again," said Fred Hamilton, who works for the Boistfort Valley Water Corp.
State forestry rules empower the Department of Natural Resources (DNR) to restrict logging on unstable slopes when landslides could put public resources or public safety at risk.
But in Little Mill Creek and elsewhere in the Upper Chehalis basin, a Seattle Times investigation found that Weyerhaeuser frequently clear-cut on unstable slopes, with scant oversight from the state geologists who are supposed to help watchdog the timber industry.
The December storm triggered more than 730 landslides in the Upper Chehalis basin, according to a state aerial survey. Those slides dumped mud and debris into swollen rivers, helping fuel the floods that slammed houses, barns and farm fields downstream.
A disproportionate number of those landslides started on slopes that had been clear-cut.
The Seattle Times, using information from state aerial surveys, examined 87 of the steepest sites that had been clear-cut. Nearly half of them suffered landslides during the storm. Those sites represented less than 8 percent of the total acreage — both logged and forested — in the Upper Chehalis and its tributary drainages. But the sites produced about 30 percent — 219 — of the landslides.
Among the other findings:
• Weyerhaeuser routinely downgraded slide risks on those sites in logging applications submitted to the state. In watershed plans financed by Weyerhaeuser and approved by the state in 1994, more than half the acreage in the sites was rated at moderate- or high-hazard potential for landslides. But in a second round of site reviews before logging, Weyerhaeuser geologists concluded that most acreage had little or no potential for landslides.
• State forestry officials often noted "unstable slopes" or "unstable soils" in checklists that accompanied their harvest approvals. But there is no record in the files of any field visits by state geologists to scrutinize the logging plans in the 42 sites that later had landslides. Forty of those sites were logged by Weyerhaeuser, two by other companies.
David Montgomery, a University of Washington geomorphology professor who reviewed The Seattle Times' findings, believes Weyerhaeuser underestimated the risks of clear-cutting.
He notes that several logged areas included features specifically defined in state rules as potentially unstable.
Logging these areas removes trees that help intercept the rain and bind the soil. Decades of studies, which have been used to help shape state forest-practice rules, show logging such slopes can increase the number and size of slides.
Montgomery wrote some of those studies. His blunt assessments of the connection between logging and landslides have sometimes rankled state and industry officials.
"If the policy is not to increase landsliding, then they have no business cutting on some of these slopes," Montgomery said. "There is not a mechanistic model on this planet that would predict cutting down those trees would do anything other than reduce stability. The only question is how much."
The December 2007 flood walloped Lewis County, causing more than $57 million in property damage to homes, farms and businesses. A Seattle Times photo of landslides on a clear-cut mountainside helped ignite a public debate about whether logging practices had worsened the flood's effects.
Weyerhaeuser and the state Forest Practices Board, which sets state logging rules, are both funding studies to look at the relationship between logging and landslides in the December storm.
In interviews, Weyerhaeuser officials place most of the blame for last year's landslides on the extraordinary amount of rainfall. Over the decades, they say, the company has made improvements in its forestry practices — some of which were credited in a 2000 report commissioned by the state with helping reduce erosion and landslide risks in the Upper Chehalis. And in some areas, they believe their logging may have made little — or no — difference in the number of landslides.
The Chehalis River's peak flood flow was more than double the previous record tracked by gauges in place since 1939. Some areas got especially soaked: The Stillman Creek drainage, for example, got 8 inches of rain in 10 hours.
Within the Chehalis River basin, the company said, there were also numerous slides in forested areas, and the company noted such slides may be underreported because they are hard to spot in aerial surveys. By contrast, Weyerhaeuser clear-cuts in other drainages that received less rain had few landslides.
"This storm was so intense that we had no basis for making judgments about what is likely to be stable or unstable. So that is kind of what we are struggling with here," said Bob Bilby, Weyerhaeuser's chief environmental scientist.
"At the same time, we are not trying to absolve us of any guilt. ... We are mounting a fairly large project to take a look at the procedures we use to deal with unstable slopes."
The DNR also is reviewing its oversight, according to Lenny Young, manager of the agency's Forest Practices Division.
In 2001, new rules more strictly defined the kinds of unstable slopes where logging could be limited. In areas that already had watershed plans, such as the Chehalis basin, timber companies were exempted from the new rules, according to Young.
That exemption, which has been in place as Weyerhaeuser clear-cut in the basin, will be re-examined by the Forest Practices Board, said Young. Still, state Lands Commissioner Doug Sutherland, who heads DNR, defends his agency's enforcement record.
"Do we have enough oversight?" Sutherland said. "With the folks available, with the data available. With the technology available. My answer would be yes, we do. Can we improve it? Definitely."
What the rules are
State laws that regulate logging on unstable slopes were forged after landslides in 1983 and 1985 killed five people. One of the landslides resulted in a jury verdict against DNR, which was accused of failing to maintain an old logging road on state land. The agency eventually paid a $2 million settlement.
These landslides were in mind as state officials negotiated with forestry companies, tribes and environmentalists over new logging rules.
Weyerhaeuser's logging around the Upper Chehalis and Stillman Creek is guided by watershed plans that were put in place in 1994. Scientists from Weyerhaeuser, the state and elsewhere rated those lands for landslide hazards based on factors including geology and slope steepness.
They then developed "prescriptions" for how the areas should be logged. In a few slide-prone areas, logging was prohibited to help protect fish, wildlife or other natural resources. In other areas, logging could be approved if certain steps such as keeping roads off risky slopes were taken, according to Gary Graves, a DNR official.
In many other sensitive areas, there was another requirement: Before logging was permitted, Weyerhaeuser would have to do a new, more detailed review of landslide hazards.
State geologists could take a second look. But they rarely did.
Water officials wary
As a drinking-water source, Little Mill Creek would appear to rank high on the list of public resources that needed protection. Watershed plans noted the intake for the water-treatment plant had been damaged in a 1990 flood, and it was vulnerable to clogging from sediment.
Weyerhaeuser expanded logging around Little Mill Creek in the late 1990s as the second-growth forests, originally cut some 50 years before, reached maturity.
"The logging was going to cause problems," said Richard Eitel, manager of the water corporation, who told the company of his concerns. "But we don't own the land, and I couldn't see any way to overcome it."
In talks with the water corporation, Weyerhaeuser officials discussed concerns about the logging. They believed they could head off problems with improved logging and road-building practices.
"We have told them that we're going to take good care of that basin," recalls Frank Jongenburger, a Weyerhaeuser forester.
The Little Mill Creek slope-stability work was done by Jim Ward, a veteran Weyerhaeuser geologist certified by the state as a "qualified expert." He scanned maps, looked at aerial photos and walked the forests to check for slide-prone areas.
Within the Little Mill Creek area, Ward placed some unstable slopes off-limits. Those were among the more than 800 unstable sites across Washington that company officials say their geologists have spared from timber harvesting during the past decade.
But in Little Mill Creek, Ward found most of the drainage had little or no potential landslide risk.
In fall 2001, Ward checked out a 68-acre tract. The earlier watershed analysis approved by the state had rated 64 percent of this land at moderate risk of slides.
But when it came time to file for a logging permit, Ward reached a different conclusion.
He cited steep slopes and an ancient landslide as "areas of concern." He also noted that the area had slope "failures" in storms of 1990 and 1996. But he found only a 3.2-acre area was at risk of sliding.
The rest of the tract is stable, Ward wrote, and it could be clear-cut.
State foresters approved the application. There is no documentation that a state geologist ventured out in the field to assess the site.
When the storm hit, the 3.2 acres still covered in forest didn't slide. But about a dozen other spots on the slopes gave way.
Ward said he was surprised by those landslides, as well as three other major slides in the Little Mill Creek drainage.
"This storm was large enough that we had failures in places that we normally didn't expect them at all," Ward said. "It just got a lot of water, very fast."
Last December's landslides and floods buried the Boistfort Valley water intake in several feet of mud. The treatment plant was shut down.
Eitel, the water-corporation official, believes state regulators share responsibility for what happened.
"They could have said 'you're going to have to limit this [logging].' Weyerhaeuser might have been mad about it. But they would have done it," Eitel said.
Some other valley residents also questioned Weyerhaeuser logging practices.
David Fenn, a valley farmer whose fields were littered with logs and mud after the storm, believes the scope of the clear-cutting has steadily made the area more vulnerable to flooding during storms.
"I live 75 yards from the river, so when it rains, I see what's going on," said Fenn.
"The difference between 30 years ago and now is just stark, in terms of how fast the river comes up ... I am not against logging and not against clear-cutting. But I am against the rapidity with which they are logging our watershed."
Reports scaled back
Through 2002, Weyerhaeuser often gave the state written geological reports to justify decisions to clear-cut some of the steep slopes in the Upper Chehalis.
But then the company stopped submitting many of those formal reports. Instead, the applications included only a few lines summarizing the findings.
Weyerhaeuser officials say this was intended to allow geologists to spend more time in the forest and less time in the office.
"We would still do the field work, but if it was routine, we wouldn't write the report," said Jongenburger, the Weyerhaeuser forester.
State officials approved of the new approach, although it made it more difficult for DNR to assess the hazards.
In the winter of 2004, for example, the company proposed to clear-cut a steep 60-acre site in the Upper Chehalis.
The earlier watershed analysis rated two-thirds of the acreage at a high potential for slides.
The logging application had no geologic report, only the notation that a field review found "no potentially unstable areas."
State foresters appeared to have information questioning that assessment. In their office review, they checked the box that listed the site as possibly containing highly erodible soils and unstable slopes. But the state foresters never called in an agency geologist for consultation.
Four landslides occurred on these slopes during the December storm.
Ward reviewed another site in the Stillman Creek area, marking two steep areas for protection. But he gave the green light to a clear-cut of 106 acres, despite the presence of steep bedrock hollows — spoon-shaped valleys on the mountainsides — that are considered slide hazards under state rules.
Once again, the company's application stated "no potentially unstable areas were found," but included no geological report. Once again, state foresters identified potentially unstable slopes in an office review but didn't ask a state geologist to check the site.
During last winter's storm, a half-dozen landslides started in those hollows and on other slopes. The stark scene was captured in a December photo by Seattle Times photographer Steve Ringman.
State geologists scrambled to figure out what happened.
"I have already gotten several questions about this picture regarding the lack of protection for the bedrock hollows in the picture," David Parks, a DNR geologist, wrote in an e-mail to Venice Goetz, a state geologist.
Goetz then went looking for a geological report on the site.
"It's not online but there are unstable slopes. Can you please send me a scanned copy via e-mail," Goetz wrote to another DNR official.
"No geo report," came the response. "Just the statement that it was reviewed."
Searching for lessons
This summer, Weyerhaeuser crews are repairing logging roads and rebuilding bridges that were wiped out by the flood.
They also are assessing their logging practices.
Weyerhaeuser officials are hoping this was a rare, freak storm that won't be seen again — at least in this corner of Southwest Washington — for hundreds of years.
"Overall, we feel like our forest practices held up pretty well," Bilby said. "It comes down to: What is the level of risk we are supposed to be managing for."
But climate change is creating a new wild card in the company's forecasting. In a recent study, federal scientists predicted the warmer world will bring more intense Pacific rainstorms.
DNR officials also are searching for lessons from the numerous landslides. One area of review: the oversight by the six agency geologists who help screen the thousands of logging applications filed each year.
"We will be looking at all the nuts and bolts ... to determine if there are any places that we are not properly implementing the rules," said Young, manager of the Forest Practices Division of the Department of Natural Resources.
Meanwhile, the Boistfort Valley Water Corp. is scrambling to complete about $750,000 worth of repairs by the summer's end. Government grants will pay some of the bill, but valley residents likely will see rate increases.
Water-company officials fear the next round of winter storms will stir up all the mud and soil deposited along the banks of Little Mill Creek during the flood, making it much more difficult to deliver clean water to their customers.
Next to the drinking-water intake, the state has approved a 27-acre clear-cut.
Laser images show a few steep spots that might present increased landslide risks. But before approving the clear-cut, a state geologist never visited the site.
Hal Bernton: 206-464-2581 or email@example.com.
Justin Mayo: 206-464-3669 or firstname.lastname@example.org.
Copyright © 2008 The Seattle Times Company
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