The Houston flooding isn’t even over yet, and planners are already blaming it on urban sprawl. That’s absurd: if 30 to 50 inches of rain fell on New York City, Los Angeles, or anywhere else over a weekend, they would have flooded too.
The Antiplanner is not an expert on hydrology, but I do know a couple of basic principles. First, the way to minimize flooding is to minimize the percentage of each acre of land that is rendered impermeable by development. Second, high-density development leads to a higher percentage of land that is impermeable. This means that sprawl is a natural defense against flooding.
Planners would like you to believe that concentrating development on a smaller land base, even if that land is made mostly impermeable, is better because more land is left permeable. But all that does is concentrate the flooding in the developed area. Continue reading
