Early claims that suburbs worsened floods were plausible but scientifically untested

Evidence

In the 1950s, a number of people began to argue that urbanization increased the volume of storm water in a watershed. The argument was logical. In a field or a forest, the ground absorbed rain and slowed runoff; once builders replaced the natural cover with smooth impervious surfaces, however, a hard rain could quickly become a torrent. The evidence seemed to support the argument. In a number of watersheds transformed by development, residents and officials reported that streams, creeks, and runs were flooding more often. But the evidence was both scanty and unscientific. No one had studied the issue. Though the reports of increased flooding were plausible, a team of Geological Survey researchers concluded in 1958, the observations might be misleading. Since the use of floodplains was increasing, “floods may appear larger and more frequent because the damage possibilities have been increased and damage occurs more frequently. This may happen even though the actual flood magnitudes have not increased.” Accordingly, the relationship between urbanization and flooding required systematic study. — Adam Rome, The Bulldozer in the Countryside, 798

Categorization

• XREF: Relates to the polyad thread listening/observation-as-method — how federal science moved from anecdote to systematic measurement. — connects to: The agriculture secretary equated postwar suburban land exploitation with the Dust Bowl — Adam Rome, The Bulldozer in the Countryside:…, 792; Federal studies proved suburbanization doubled to quadrupled storm runoff by 1970 — Adam Rome, The Bulldozer in the Countryside:…, 803; Suburban sprawl created flood damage faster than engineered protections could counter — Adam Rome, The Bulldozer in the Countryside:…, 698