Topography Do you live at sea level or in the mountains? Is your street flat or hilly? How close are you to the nearest stream or river? Where is that river's floodplain? If your neighborhood has a lot of hills, do you live on a hillside facing the north or south, or are you on top of a ridge? Topography describes the physical features of a place, or the terrain, such as mountains, valleys and floodplains. Topography, or the shape of the surface of the earth, influences water drainage, soil erosion, and plant growth. Topography also directly impacts construction and maintenance of roads or buildings. Floodplains, particularly important to North Carolina residents, are normally dry areas that are susceptible to inundation by a stream, river or lake following a storm or flooding upriver. When an unusual amount of rain falls, rivers can swell and overflow their banks flooding the flat valley land on either side. Human development in river basins and floodplains can drastically alter the way water flows. Straightening and deepening streams, draining wetlands, building roads or bridges that act as dams all affect the way water flows. A home or business built outside the 100 year flood plain 30 years ago might find itself in the middle of the floodplain today. Resources for Learning about Topography The North Carolina Geological Survey The North Carolina Geological Survey (NCGS) examines, describes, and maps the geology and mineral resources of North Carolina and publishes these findings in NCGS reports and maps. The NCGS administers cooperative geologic mapping agreements with the U.S. Geological Survey, other federal agencies such as the National Park Service, and other state and local government agencies. American Geosciences Institute Geologic maps for the environment, hazard mitigation, resource evaluation and land use planning. Also includes information on the usefulness of geological maps and how to read them!