Rational landslide policy is a slippery slope
By KATE JANEWAY
This winter's storms confronted us, once again, with the complicated issues surrounding construction in landslide-prone areas.
Landslides are a dramatic manifestation of the collision between humans and other natural forces. Human impacts in the natural world generally appear subtly, over time, through a slow deterioration of water or air quality or a loss of vegetation. These types of impacts are often not apparent until they reach a critical level. Landslides, by contrast, are hard to miss.
With each landslide episode the impacts worsen because of the increased density of development and the escalating costs of infrastructure replacement. Solutions are difficult to craft for a number of reasons:
From a geologic perspective, landslides are frequent occurrences. From a human perspective, they seem rare events. When decades separate landslide episodes, dramatic changes can occur in land use patterns and density. Buildable land is increasingly scarce. The appeal of the views begins to outweigh the risks. The value of the land increases. We figure that lightning won't strike twice. We forget. We regain our sense that we are in control of these forces. Then, when landslides recur, we are shocked and disbelieving.
There were few surprises from this winter's landslides. The hillsides that slid are known to be landslide prone. Many of them have experienced previous slides within the last two decades. In the aftermath of these devastating landslides, we are faced with a choice: Do we clean up, fix up and go on as before? Or do we face the challenge of crafting solutions that are rational and fair?
I'll give you odds ...
Predicting landslides is an inexact science. Geotechnical engineers and land use policy-makers can tell us which hillsides have a natural tendency to slide into Puget Sound or the nearby ravine. When they will slide is anyone's guess.
When a slide occurs, it becomes a case of whodunit?; Was it simply time -- in geologic terms -- for this section of hillside to do what it was meant to do? Was the weather to blame? Was it development on the site? Was it development below, above, or a block away? Was it clogged storm drains? Was it the road?
Many of the houses in landslide-prone areas have been there for a very long time without serious difficulties. Even in landslide-prone areas we are apt to regard damage or loss as a matter of bad luck, not bad choices.
There must be an engineering solution
It is extremely expensive to engineer hillside stability, and there are limits to the effectiveness of any attempt to thwart a natural process. Should the public pay to shore up all unstable hillsides? If private landowners pay, do they assume liability if there are slides in any case?
A developer or landowner who is willing to endure the expense can do a lot to stabilize a structure on a hillside. This does not mean that the hillside will stay put. If the hillside goes, the houses that were built decades ago may go with it.
Don't build there!
Telling people not to build in a landslide-prone area seems an obvious approach. But this places the burden on government to prove that construction would be unsafe. When decades elapse between slides, this kind of "proof" is difficult.
People want to build where they want to build. Landowners and developers are often willing to play the odds that they will be lucky. The determination to build and to enforce the right to build with lawsuits have made policy makers and regulators gun-shy.
Work it out amongst yourselves
"You build at your own risk" has a certain appeal to it. If the only impacts from a landslide were the loss of one's own property, this approach would make some sense.
But landslides are neither neat nor discriminating. They may take your house and your neighbors'. They may also take out streets, parks, and utilities in their path. This is where the taxpayer gets hooked into the solution.
The risks inherent in hillside development are apparent. And it is easy to appreciate the unfairness of imposing the costs of private landslide damage on the public. But when a landslide takes several homes, a street and three utility lines, government cannot turn away.
The need to respond to citizens in need and to repair public infrastructure means that we all share the costs of landslide damage. Until roles, rights and responsibilities are clearly defined, governments will be forced to perform the essential repairs.
What makes sense?
Other cities and states have lessons to teach us. An effective landslide prevention and mitigation policy has a number of elements: