Rivers, Floods, and a Human Reckoning | Lisa Raleigh, PhD | TEDxAsheville

Lisa Raleigh opens by describing her lifelong connection to rivers across Montana, Colorado, and western North Carolina, framing herself as a natural advocate for rivers. On September 27, 2024, Hurricane Helene caused the Swanoa River to swell to a size larger than the Mississippi, sweeping away buildings, vehicles, and bridges. When the floodwaters receded, the river banks were unrecognizable, marking a turning point in her relationship with rivers.

As executive director of Riverlink, a 40-year-old Asheville-based conservation organization, Raleigh notes that catastrophic flooding is not new to the region — the French Broad and Swanoa rivers flooded massively in 1916, leaving a high watermark still visible in the Riverlink office. Before Helene, Asheville's rivers contributed $3.8 billion annually to the regional economy through tourism and outdoor recreation. After Helene, the Swannanoa community saw riverfront buildings reduced to rubble, and sections of the beloved River Arts District greenway simply vanished.

Raleigh explains that flood damage is not purely natural — it is shaped by how humans develop and manage river banks. She cites geographer Gilbert White's observation that 'floods are acts of God, but flood losses are largely acts of man.' Central to her argument is the concept of riparian zones — the lush, tree- and shrub-filled buffers along river banks that protect both the river and surrounding land. Where healthy riparian zones exist, river banks remain intact even after extreme flooding. However, human activities like urban development, transportation infrastructure, and agriculture routinely strip these zones away, leaving banks bare and unable to slow floodwaters, direct debris, or maintain structural integrity.

Climate change compounds these vulnerabilities. Since Helene, deadly flooding has struck central Texas, Valencia (Spain), and Vietnam, where nearly five feet of rain fell in 24 hours. Raleigh describes how warming oceans are fueling stronger, farther-traveling storms that dump unprecedented rainfall, and how two independent weather events can stack — as they did with Helene — to overwhelm entire watersheds. This creates a 'perfect storm' of overdeveloped river banks meeting extreme weather.

Despite the scale of the problem, Raleigh acknowledges the difficulty of change: private property lines rivers throughout the French Broad watershed, decades of investment exist in floodplains, and developers, governments, and residents all have competing interests in river-adjacent land. She argues that Helene has proven these interests cannot be treated as separate from the river's well-being — they are inextricably linked, and solutions require capitalism and environmental stewardship to become allies.

Raleigh closes with four concrete calls to action for community members to bring to decision makers: (1) champion 50-to-100-foot riparian buffers on all riverfront properties; (2) discourage placing new greenways too close to rivers at the expense of riparian zones; (3) support voluntary buyouts of repeatedly flooded properties to return land to open space; and (4) insist local governments prioritize and fund river and stream restoration. She concludes by noting that the Riverlink office doorway now bears two high watermarks — 1916 and Helene, 18 inches higher — symbolizing that the past is no longer distant history, and urging the community to give rivers a voice in decision-making before the next flood arrives.