According to popular wisdom, rapid population growth is the biggest threat to the coastal environment. It’s a classic case of trying to put ten pounds of potatoes in a five-pound sack. Or is it? At first glance, national statistics appear to confirm that perspective. Coastal counties cover 17 percent of the land area of the United States. Coastal watersheds, as described by the Department of Agriculture, represent just 13 percent of the nation’s acreage. By any measure, the coastal zone is a small part of the country, but it is home to more than half of America’s citizens. Moreover, today’s coastal populations are just the tip of the iceberg. Over the next 15 years, 27 million additional people—more than half of the nation’s population increase—will funnel into this narrow corridor along the edge of the ocean.