Floods can drastically change the land in an area due to

Removing vegetation and soil, grading the land surface, and constructing drainage networks increase runoff to steams from rainfall and snowmelt. As a result, the peak discharge, volume, and frequency of floods increase in nearby streams. Changes to steam 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, in clouding inundation and erosion, as new development continues.