Head for the Hills

We're not used to homes being destroyed or rendered inhabitable by environmental disasters. That's what happens in Bangladesh, or New Orleans. But it happens closer to home as well, as the News Journal reports:

Now, most of Glenville is gone, bought out in a $34 million project to get residents out of harm's way. The state tore down 167 of the 194 homes -- with one more to go -- and fenced off the lowest-lying areas, which soon will be excavated as part of a 52-acre wetlands "bank" that can be used to offset future highway projects.

It has been more than four years since Tropical Storm Henri flooded the Red Clay watershed. But could it happen again, elsewhere in the watershed? Was this just a fluke, one of the many storms of the century as it were?
The concept of the storm of the century is captured in the concept of the 100-year flood, and mapped by federal, state and local planners.

Revisions to flood-plain maps are common and reflect new development and other factors that affect the way water flows. The maps show where the water is likely to reach flood stage in a 100-year flood (a storm with a 1 percent chance of occurring in a year) and a 500-year flood (a storm with a 0.2 percent chance of occurring in a year).
FEMA's most recent maps use flow data that is 22 years old, according to Mike Powell of the state Division of Soil and Water Conservation. The new maps will include data from the 2003 Red Clay flood, which was considered a 500-year flood, as well as 100-year floods in 1999 and 2004.
The potential affect of those changes is alarming to some property owners.
"They may put 1,000 homes into the flood plain that are not in the flood plain now," said Ed Boisvert, vice president of the Glenville Civic Association, who has represented the community in meetings with government officials. "If that happens, all those people have to buy flood insurance, property values deteriorate and there is a lot of politics."

We've become accustomed to building what we want, where we want. When government proposes limits on development, we hear cries of property rights being taken away. But Mother Nature is less amenable to pressure from developers.
Thousands of homes have been built upstream since the 2003 deluge, increasing the amount of water than runs directly into streams in a hard rain. Realtors and developers may not like to see maps with expanded flood plains, but the increased risk of flood is determined by the laws of nature, not the calculations of mapmakers.