U.S. GEOLOGICAL SURVEY Fact Sheet 076-03 Effects of Urban
Development on Floods By C. P. Konrad Over the past century, the
United States has become an increasingly urban society. The
changes in land use associated with urban development affect
flooding in many ways. Removing vegetation and soil, grading the
land surface, and constructing drainage networks increase runoff
to streams from rainfall and snowmelt. As a result, the peak
discharge, volume, and frequency of floods increase in nearby
streams. Changes to stream channels during urban development can
limit their capacity to convey floodwaters. Roads and buildings
constructed in flood-prone areas are exposed to increased flood
hazards, including inundation and erosion, as new development
continues. Information about streamflow and how it is affected
by land use can help communities reduce their current and future
vulnerability to floods. Flooding in Hickory Hills, Illinois,
prompted the construction of a reservoir to control runoff from
upstream areas. So