Sunday, November 18, 2007

Western North Carolina Mountain Slope Construction... Is It Safe?

Gambling with the Unknown

New data from the North Carolina Geological Survey shows that the rain storms of September 2004 set off 155 landslides, caused five deaths and destroyed 27 homes in the western counties of North Carolina.

Since these regional fifteen county disasters there has been an explosion of mountain resort development in Western North Carolina. No one is certain what impact this will have on mountainside stability, but geologists know and have stated that this increased residential and resort construction on mountain slopes is exposing more people to the threat of landslides.

Landslides do happen spontaneously but evidence shows that most slope failures in Western North Carolina are caused by improper construction practices. According to state geologists, building resorts and subdivisions on mountain slopes necessitates cutting roads into steep terrain and placing homes on vertical slopes. The infrastructure for this development requires burying piping for water, sewage, and septic systems in degraded and vulnerable ground. If construction for these projects is not done safely and carefully, these artificially created slope sites will fail.

Local environmental officers are also expressing alarm about Western North Carolina's unregulated building practices. On March 27, 2006 Marc Pruett told the Haywood County Commissioners: "Currently anyone with a bulldozer and backhoe can carve out home sites and roads into the mountainside. This lack of engineering is causing homes and roads to slide down the mountain throughout the county."

Pruett, who directs the county's erosion-control program, has a slide show he uses to illustrate the ongoing local disasters. Please see "Disappearing Haywood" by Jeff Schmerker, The Enterprise-Mountaineer, October 31, 2005.

Pruett's shocking photos show roads that have simply disintegrated as the land beneath them has shifted. There are images of chocolate-brown waterways clogged with runoff from construction. Others show slopes so steeply cut that they are continually eroding. Homes fare no better. Some have been knocked off their precarious perches by landslides;foundations are laced with cracks so big you can see daylight. Still other houses are being ripped to bits as the "solid ground" they are built on starts to move. And in just about every case, says Pruett, a combination of substandard construction and inappropriate sites is to blame.

Jeff Turner, District supervisor for Buncombe County Soil and Water, stated in a letter to a local newspaper in January 2007 " I, along with many of you, have personally witnessed the condemned homes from past quick development of mountainous terrain. We have already learned our lesson here. We don't need anymore of this. Some of these homes, only a few years old, are now just worthless investments. Developers who code jump or try continually to get variances on legitimate ordinances should be run out of town and forbidden to ever contract in our county again." MountainXpress, " Economic development meets steep-slope reality" January 31, 2007

In the spring of 2005 a landslide covered Oak Street in downtown Spruce Pine. "It's a gravity thing," said Alex Glover, a geologist for Zemex Industrial Minerals. "It's a fact of nature, there's nothing that can be done to stop more debris from falling." Mitchell News-Journal, March 16, 2005, "It's a gravity thing" by Nathan Hall. As reported in the article, Glover said the town can
install permanent barriers to block or catch falling debris, but the construction will be expensive and there is no way to permanently stabilize the bank.

"It's a bad situation," he said pointing to a large slab of exposed rock, its sections clearly slanted toward Oak Avenue. "It's like a stack of dominoes, tilted, and now loosening and falling apart." Glover said the sections of rock called "Ash", a group of old ocean -type sediments mixed with volcanic sediments. He said the formations, millions of years old, were originally formed to be flat, but shifted due to mountain building. He said as the rock degrades, it forms Saprolite-which is basically weathered, rotten rock.

Western North Carolina's "Build Anywhere" approach is a developer's dream but a potential nightmare for unsuspecting buyers and current property owners. State geologists and other informed professionals warn that the consequences of error can be great when homes and roads are carelessly placed on questionable mountain slopes. The profitable but dangerous practice of up mountain slopes significantly increases the possibility for slope failures particularly in weathered rock regions. There are safe building locations in Western North Carolina but these sites can only be determined by state licensed experts. For unbiased information about Western North Carolina landslides and safe building standards please visit the North Carolina Geological Survey and local environmental offices.

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