Landforms

1. Landforms • Rivers and streams • Erosion – the process of water (wind or ice) wearing or washing away earth material. • Large volumes of earth material wash away more earth material • Fast water increases the amount of erosion and moves earth material farther

2. Desposition The process where earth materials are picked up by water, wind or ice and put down in another place.

3. Rivers and streams • Deposition- earth material drops out of water as it slows down. Smaller particles like clay take longer to settle. They stay suspended in the water longer. • Order of settlement or deposition: Boulders, rocks, pebbles, sand, silt, clay Clay is deposited on the banks of slow moving streams.

4. Streams • Intermittent-come and go with the seasons and weather conditions • Some lakes are also intermittent. • Perennial- always flowing though not necessarily at the same level.

5. Deltas • Deltas are large fan shaped deposits of earth material at the mouth of streams and rivers. • Alluvial Fans- are very large deltas formed when there is a sudden change from a steep slope to a flat plain. They are often very fertile deposits of soil.

6. Mississippi Famous Rivers The Mississippi was formed from a glacier in the last ice age. a. the floodplain is miles wide below St. Louis and the sediment causes very fertile land. b. the wide channel from St. Paul to the Gulf of Mexico is very important for transporting grain.

7. The Hudson River flows from the Adirondack Mountains through New York State to the Atlantic Ocean. a. Its mouth (near New York City) is below sea level so it is affected by tides and is salty. b. It flows through steep rock cliffs called palisades. c. It provided waterpower for lumber and textile mills. d. The Erie Canal connects the Hudson with Lake Erie

8. Colorado River Formed the Grand Canyon Provides water and power (Hoover Dam) for much of the Southwest.

9. Maps • general reference-used to locate places and boundaries (political maps), and show geographic features (physical maps). • mobility- help people move from one place to another, roads, railroads etc. • thematic- shows such things as population or weather patterns • inventory – shows location of objects (stadium map, building map) • Topographic- shows physical features of a landscape including contour lines and elevations.

10. Making maps • gather data-(observe the playground) • make careful measurements • record information (rocks, forests, etc.) • Models- smaller versions of large objects, larger versions of small objects -can represent landforms and human structures • Maps- can represent landforms and human structures • Cartographer- person who makes maps

11. Horizontal and vertical lines evenly placed called grid lines are often used on maps. They allow easy reference points and make it easier to enlarge And shrink maps. The gridlines are labeled with an X and Y axis.

12. Topographic or Contour map Contour lines- lines that connect points of equal elevation Contour interval- difference in elevation between contour lines-the closer the lines, the steeper the slope. Bar scale- shows the relationship between the distances on the map and the distance on the ground Scale: Ratio or fraction showing the distance on the map compared to the distance on the ground. (Representative fraction) Example 1:6,150

13. Topographic maps cont. The distance, elevation, position, and boundaries are measured by a surveyor. A surveyor puts permanent markers in place called benchmarks to show elevation and location. 0 elevation is sea level