Slope failure, or mass wasting as it is sometimes called, is the process by which material moves down a hillside. This process occurs on all hillsides to some degree, but it tends to affect hillsides with steep grades the most. There are a number of different types of slope failure, but only two will be discussed here because those are of particular importance in western North Carolina. The first type is what is known as a debris flow. A debris flow is a mixture of sediment, organic material, and water that is able to move down hillsides at rates of up to forty miles per hour. The second type is known as a slump in which the base of a hillside is undercut. This deprives the upper part of a hillside of support, causing the hillside to collapse.

Slope failure is normally caused by three primary factors, though the actual event is normally a combination of the three. The first factor is increasing the degree of a slope. Steeper slopes tend to be more unstable and more prone to slope failure. When buildings are placed on hillsides, the angle of the slope is often increased. A second factor that leads to slope failure is the removal of vegetation. Natural vegetation holds the soil together and prevents it from moving downhill. Once the vegetation is removed, the stability of the slope is lessened. The final factor that contributes to slope failure is the introduction of significant amounts of water to a slope. When sediment becomes saturated, it begins to flow like a liquid and can carry large amounts of debris with it. These flows can travel at high speeds for long distances.

The issue of slope failure is of particular importance to western North Carolina because the area is extremely prone to earth movements. The North Carolina Department of Emergency Management has previously declared that the western part of the state is a high risk area for slope failure. As a result, insurance companies will not cover damage caused by earth movements. The North Carolina Geological survey is currently developing hazard maps which pinpoint the most landslide prone areas, but this will not be completed for years. In recent years, there have been a number of earth movements in the area that have caused both property damage and loss of life. The most severe instance of this happened in Macon County in 2004 when a debris flow along Peeks Creek killed five people and destroyed fifteen homes. The flow traveled 2.25 miles and was clocked at 33 mph. Another debris flow occurred in Jackson County in 2005. While it did not result in any fatalities, it did damage the property of two landowners. A team from the North Carolina Geological Survey investigated the incident and found that the primary cause was the slope alterations made by the Jackson County airport which is located above the affected property. A final incident happened in Haywood County at Hunters Crossing in 2005 when a slope that was undercut due to construction began to collapse, resulting in the destruction of two condominiums.

Because of the repeated occurrences of slope failures in North Carolina, counties are now looking at enacting steep slope ordinances in order to prevent construction on potentially unstable slopes. The state of North Carolina has seen the potential for slope failure as a hazard for sometime. In 1983, the state passed the Mountain Ridge Protection Act which declared that counties were within their rights to enact ordinances regulating construction along mountain ridges and slopes because of the risk they created for people living at lower elevations. Jackson County has recently enacted a steep slope ordinance that has been seen as highly controversial due to the constraints that it places on property owners. The new steep slope ordinance requires that anyone who wishes to build something other than a single family home on a slope greater than thirty percent must provide reports to the county on the soils, hydrology, vegetation, and the possible effects on the slope. The ordinance also limits the number of structures that can be placed on slopes above thirty percent.

The primary argument in favor of steep slope ordinances is that construction along steep slopes is a hazard and thus needs to be regulated in order to ensure the safety of the general public. The fact that there has been a history of lethal earth movements in the past gives credence to this viewpoint. Developers are often able to build without anyone monitoring the stability of the slopes. Supporters of slope ordinances feel that developers are putting them and their property at risk by building on steep slopes. While they understand the importance of property rights, they feel that the developers are infringing on their rights by putting them at risk.

Supporters of the steep slope ordinance are also partially driven by the fear that developers will ruin the appearance of the region by tearing up the mountains to put in developments. More and more houses are beginning to cover the mountainsides as people move to the area trying to find some peace and quiet, along with a good view. People who have lived in the area for a long time do not wish to see it built up and turned into a gigantic tourist resort. While the fear of overdevelopment is understandable, development does bring with it some advantages. An increased amount of development could lead to more businesses and an improved local economy, though this does come with its costs.

Opponents of the steep slope ordinance feel that the ordinance interferes with their property rights because it limits what they can do with their personal property. They feel that the government has no right to tell them what they can and cannot do with their land. This stands in opposition to the supporter view which holds that the right to do whatever one wants with one’s property ends when one begins doing something that will potentially cause harm to the property of other people. Even if a person wishes to dump toxic waste on their front lawn because it is their property and they can do what they want with it, their neighbors can legitimately complain because of the effect on their property. The same view could be applied to developers who build in a way that puts people living down slope at risk. The issue then becomes where to draw the line. At what point do developers begin causing a significant enough problem that it is necessary to legislate to ensure public safety? Another issue with property rights that should also be considered is the fact that people whose property falls under the steep slope ordinance automatically have property that they cannot use for development, but they still have to pay taxes on. The ordinance effectively deprives them of their property by making it useless for development.

A final issue with the ordinance is the potential harm it could cause to the construction industry and to the economy. The introduction of the slope ordinance could potentially cause developers to move to other counties that lack slope ordinances which could lead to a decrease in the amount of construction work available. This could then potentially cause wider harm to the economy overall because the loss of construction work would then mean an overall loss of money in the county. This is hypothetical however because there is no way to be certain that the slope ordinance would keep developers away from the area.

While there are a number of factors to look at when examining the slope ordinance issue, it largely boils down to the issue of property rights versus public safety. How much can the government legitimately legislate in order to protect public safety before they begin oppressing the rights of people to do what they want with their private property? It is largely dependent on how extreme people feel the risks of slope failure are. There is no question that western North Carolina has a history of being prone to slope failures that have the potential to cost lives. The question is how great those risks are and whether it is worth it to restrict property rights in order to potentially save lives.

Additional Resources:

• Read the Mountain Ridge Protection Act legislation.
• Read the report from the North Carolina Geological Service about the hurricane-induced slope failures that affected Western North Carolina in 2004.
• Read the report regarding slope failures near the Jackson County airport in 2005.
• Read a study from the Z. Smith Reynolds Foundation that outlines the impact of campaign contributions on land use legislation.
• Read a 2007 report from the North Carolina Geological Survey on landslide hazard mapping in western North Carolina.