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HomeMy Public PortalAboutLandslidesIdaho Statesman March 17, 1997 page 1 of 4 The Flood Next time Katherine Jones/ The Idaho Statesman Shattered dream: When spring runoff begins, the slope above Trail's End restaurant in Lower Banks is expected to slide again. Mary Lou Holton, who owns the restaurant, has been ordered to leave, as the community has been declared unsafe. Clear-cuts, roads, fire suppression: Human touch results in no-man's land By Rocky Barker The Idaho Statesman Lower Banks was no more than a wide spot in the road and the restaurant was in dis- repair. But Mary Lou Holton saw something in the desolate Payette River Canyon, enough to pin her future on it. She bought the run -down prop- erty and turned it into the Trail's End restaurant, store, gift shop and Part motel. "The view was phenomenal," she said. She didn't know then that the odds were stacking up OF 5 against her. Two PARTS years earlier, a Pennsylvania cou- ple started the Cottonwood forest fire when sparks flew from the wheel rim of a car they were pulling be- hind their motor home. The fire burned through the dense forest covering the steep slope across Idaho 55 from Trail's End. When Idaho suc- cessfully sued the couple, the state used the settlement to help pay its firefighting costs. The owner of the steep parcel, Jim Powell, didn't get any money to replant or stabilize the slope, and he couldn't afford it himself. Five years later, the trees' roots had rotted away. On Jan. 1, with nothing to hold the slope in place, mud and rock came sliding down on Holton's dreams. "This is absolutely my worst nightmare," she said. The same thing is happening across the Pacific Northwest, where two seasons of winter rainstorms have triggered mas- sive movements of the earth. Landslides happen naturally, when steep slopes become satu- rated and collapse. But logging, road building and fire control compound the problem and make it more destructive. Some slides are deadly. Along Hubbard Creek in the Cas- cade Range of Oregon, mud and rock crashed into the "WE HAVE A TENDENCY TO ABSTRACT OURSELVES FROM NATURE AND THINK IT ALL HAPPENED IN THE PAST." David Alexander, Payette National Forest supervisor in McCall Idaho Statesman March 17, 1997 page 2 of 4 The Idaho Statesman Mud and rock flowed down the slopes above Lower Banks in January, into the Trail's End restaurant, hotel and store. Later, Boise County officials declared the area unsafe and told residents to move. home of Rick and Susan Moon on Nov. 18, 1996, killing the couple and two friends. The slide originated on private timberland that loggers had cleared of trees in 1987. Another woman was killed in November when her car was carried off an Oregon highway by a slide that start- ed in a clear -cut area. Their deaths serve as a re- winder: The process that cre- ated the scenery that attracts us is continuous and some- times frightening. The plants, animals, soils and streams in a forest — the ecosys- ­tem — grow accustomed to a cer- tain cycle of fires. In the Boise Na- tional Forest, dominated by pon- derosa pines, small fires naturally burned through every 10 to 30 years, leaving the big trees be- hnd to hold the soil. �. When the Forest Service start - ed putting out these smaller fires at the turn of the century, the for- est grew denser and more prone to larger catastrophic fires. When those fires came in the early 1990s to the Boise forest, hundreds of thousands of acres were denuded of all vegetation. Five years later, the roots rotted and slopes came down as they did in Lower Banks. But in the spruce - dominated Payette National Forest, fires in 1994 burned within the normal cycle. This winter's storms still triggered landslides in areas such as the South Fork of the Salmon River but they proved beneficial to the ecosystem. Sheets of water ran off of the fire -burned areas, picking up large dead trees and depositing them in the river. New pools and ripples will develop around them, providing important fish habitat. "You want floods," said David Burns, fisheries biologist with the Payette National Forest. "They rejuvenate the stream channel." Foresters today balance two methods of thinning dense stands of trees: encourage logging and the roads that go with it, or let fire do the thinning and risk losing control. Either choice may bring more landslides. For Burns, whose primary in- terest is fish, the choice is easy. "Fire is by far less riskv to fish habitat than anything else we do on the landscape," Burns said. "Given a choice between logging and fire, I'll take fire every time." But in another area of the Payette forest, fire may have con- tributed to flooding in January that damaged or destroyed more than 40 homes along the Little "IF THEY STOPPED CLEAR - CUTTING TODAY, THEY WOULDN'T GET A REDUCTION IN WATER FLOW FOR YEARS." Cecil Bilbio, Cambridge rancher Idaho Statesman March 17, 1997 page 3 of 4 Salmon River. That makes the choice more difficult. "In other watersheds," Burns acknowledged, "society can't allow us to do that." Clear -cuts Like forest fires, clear -cut log- ging removes most of the forest canopy and increases the amount of water that flows off an slope. It also can leave little root structure to hold the soil. A U.S. Forest Service study of clear- cutting in the Western Cas- cade Range of Oregon concluded that non -road related landslides occur nearly three times more often in clear -cuts than in forest- ed areas. Based on similar studies, and prompted by public outcry at the five landslide deaths in 1996, the Oregon Board of Forestry urged landowners to limit logging and road - building in landslide -prone areas. But the board stopped short of banning either. Idaho has far fewer clear -cuts in steep terrain than Oregon and Washington and most are small- er. One area where clear- cutting is extensive is the western side of the Payette National Forest, in the upper drainages of the Weiser River. There, landslides aren't the issue, but flooding is. The Weiser River has no flood - control reser- voirs and is prone to flooding. Farmers and ranchers in Cam- bridge, Midvale and Weiser have complained that clear- cutting ac- celerates the runoff from winter snow, leaving them with too little water in late summer to finish ir- rigating their crops. U.S. Geological Service data supports their claim. Since the 1940s, the runoff has steadily started and peaked earlier. This early peak causes flooding as well, said Cecil Bilbio, a Cam- bridge rancher who formed Friends of Cuddy Mountain to op- pose clear- cutting. "If they stopped clear- cutting today, they wouldn't get a reduc- tion in water flow for years," Bil- bio said. But the study area may be too narrow to draw sound conclu- sions. Forest Service scientists say they can't begin to measure an increase in water flow until 15 percent of a small tributary's en- tire watershed is clear -cut. "You've got to look at the bigger picture," said Greg Lesch, Payette National Forest hydrologist. SY4fe.sdrrrril /011y -ch 1 *7,i99 ?d�c .9 or y Katherine Jones / The Idaho Statesman A new gorge: Old Idaho Highway 17 is a good example of how a road built through steep terrain can redirect water and cause erosion. Other activities Clear- cutting isn't the only problem with the Weiser River, Lesch noted. Much of the low- lands is planted in crops and even more is open range where live- stock have trampled. Overgrazing starts a cycle of erosion along streams, resulting in "downcutting," or deepening of the channel, Bureau of Land Management studies show. When streams are downcut, they don't spill out into their historic flood plain, so flow is contained in a narrower area and water velocity increases. That causes greater damage downstream. When temperatures rise later this month or in April, the moun- tain above Holton's business is ex- pected to begin moving again. Since Boise County declared the community of Lower Banks unsafe and uninhabitable, Holton has no choice but to move on. She's waiting for disaster aid from federal, state or local officials. "Our main goal is to get out of here and start our business else- where," Holton said. "When we came, that slope seemed a long way away. It doesn't seem so far away now." What humans do to intertere with the natural flow of water is behind much of the damage Idaho Statesman March 17, 1997 page 4 of 4 caused by January's storms. Cold temperatures quickly stopped the flow of water and mud, but time won't stand still. "We have a tendency to ab- stract ourselves from nature and think it all happened in the past," said David Alexander, Payette National Forest supervisor in Mc- Call. Unstable underpinnings The Idaho Batholith, which underlies the central part of the state, is made up of broken granitic rock that erodes into gravel, sand and silt. Soil scien- tists have known since the 1950s that roads and logging in steep areas of the batholith cause mas- sive soil movement which blows out roads and clogs rivers. The best road systems are built on top ridges, not scraped along rivers or cut into steep slopes. But Idaho's steep geography limits where roads can go. Even vital re- gional links have been forced into the wrong places — roads such as U.S. 95 through the Little Salmon River Canyon, Old Highway 17 through Garden Valley and Idaho 55 on the Payette River. Foresters and engineers are learning where they can and can't go. Still, thousands of miles of old forest roads remain, bleeding mud into rivers and triggering slides. Roads in the Boise and Payette forests alone stretch for more than 8,000 miles — the dis- tance from Boise to London. Many of the roads no longer have value for timber harvesting, said Dave Van De Graaff, timber- land manager for Boise Cascade in Emmett. "If you build roads you need to build them right or put them to bed, one or the other," he said. Debate on roads Congress has told the Forest Service to sell timber and use part of the money to close roads. The Idaho Statesman A ticking time bomb: Burned trees from the 1989 Lowman fire pro- trude from a heavy snowpack. The fire left thousands of acres barren and vulnerable to rapid runoff and landslides. "To us, doing nothing is insane," said Frank Carroll, Boise Nation- al Forest public information offi- cer. "Using those trees to generate dollars for restoration makes sense." That approach encourages a cycle of more roads and more tim- ber cutting. Another approach would halt logging and allow forests to recov- er in areas where roads have caused the most damage. These include the Clearwater National Forest in Idaho's Panhandle. "We were on the way to recov- ery but we didn't obliterate enough roads in time, and the wa- tersheds came unglued," said Al Espinosa, a former Forest Service biologist from Moscow. The same conditions exist in the Boise and Payette national forests. Few roads have been closed there, either — except by nature. Even when nature closes roads, the Forest Service sometimes re- builds. A 1995 flood so powerful it cut a new channel for the Middle Fork of the Boise River also blew out miles of forest roads. The For- est Service rebuilt, and some of the roads have washed out again. The agency proposes rebuilding. "That's like setting the time bomb to go off all over again," said Ron Mitchell of the Idaho Sport- ing Congress, which has sued the Forest Service and lost over the road - building issue. Boise - Cascade lost few roads from the January storms on pri- vate land the company logs. Van De Graaff credits a well -built road system as well as an aggressive thinning and harvesting program that reduces the risk of cata- strophic fires. "The first thing you've got to do is control the wildfires," Van De Graaff said.