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The Great Plains. Physical Geography Topography –Elevation rises gently from east to west –Southern half unvaried topography –Northern half characterized.

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Presentation on theme: "The Great Plains. Physical Geography Topography –Elevation rises gently from east to west –Southern half unvaried topography –Northern half characterized."— Presentation transcript:

1 The Great Plains

2 Physical Geography Topography –Elevation rises gently from east to west –Southern half unvaried topography –Northern half characterized by “badlands”

3 Physical features of the Great Plains

4 Prairie Potholes

5 Physical Geography Precipitation –Most results from air mass interaction –Anywhere from 10-40 inches annually; decreases from east to west –About 75% of the precipitation occurs April through August –Major droughts occur vigesimally (20 yr cycle) 1890s, 1910s, 1930s, 1950s, and 1970s

6 Precipitation Variability

7 Physical Geography Temperatures –Extremes in temperatures because of continentality –Steppe (B), Continental (D) and Humid sub- tropical (C) climates –Fluctuations increase from south to north –Northern Texas has over 240 frost free days each year; Canada’s prairies less than 90

8 Physical Geography Climate varies greatly in the Great Plains

9 Physical Geography Winds: a mixed blessing –Among the highest velocities in North America in late spring and summer Ensures maximum efficiency for windmills High rates of evapotranspiration can minimize the precipitation effects

10 WIND POWER “Certainty Rating of the Wind Resource”

11 Physical Geography Chinooks Blizzards –Occur when cold polar air masses push south along the Rockies; can last for several days Tornadoes –Far more tornadoes annually than any other comparable area in the world –Parts of Texas, Oklahoma, and Kansas encounter 200 – 300 per year

12 Tornado Frequency

13 Physical Geography Vegetation –Tall and denser grass in the East, shorter and relatively sparser in the West –Intricate root systems, difficult to plow “Bonanza teams” required to break sod

14 Physical Geography Hydrology –Great rivers, but supply strained –Use of aquifer

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16 Historical Settlement Plains Indians –Limited pre-European occupation –Buffalo (bison) hunting primary activity –Semi-permanent settlements along streams –Greatly improved their mobility once the early Spanish explorers left behind horses

17 Historical Settlement Early Problem Areas –Average annual precipitation < than East –Variable precipitation –Violent storms –Winter blizzards; snowdrifts –The hot, dry winds carried away topsoil –Sparse natural water supply to support tree growth = no wood for building, fuel, fencing, etc. –Ground difficult to plow

18 Historical Settlement Settlement initially halted along eastern margins Permanent settlement initially inspired by the Homestead Act (1863) –Gave 160 acres of land free to each settler 1867-1885: ranching was a viable alternative Late 1870s: barbed wire, lumber, and windmills helped to overcome environmental constraints

19 Historical Settlement Migration patterns: Chain migration Naming of locations

20 Aging in the Great Plains Depopulation by US County Percent elderly by US County

21 Political Economy Agriculture: Boom and Bust –Technology paves the way –Water laws –Droughts –Dust Bowl (1930s)

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24 Agriculture Wheat Shipment Patterns: –Canada: In East, to Winnipeg; then Thunder Bay In the West, Vancouver by rail then sea –US Across the Great Lakes or down the Mississippi River

25 Agriculture Key Spatial Processes –Migrant Labor Not to be confused with migrant workers who harvest crops in other regions Comprise large crews that use numerous combines and trucks Travel from Texas in early June and follow the wheat harvest north into the Prairie Provinces ~four months total work

26 Agriculture Key Spatial Processes –Sidewalk Farmers: Live in town and travel to their various acreages nearby –Suitcase Farmers: Live far from their fields and only visit them occasionally Other Crops…

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32 Energy Resources Panhandle Field of Northwest Texas, Oklahoma, and Kansas –World’s leading supplier of natural gas –All three are major petroleum producers, along with Wyoming and Alberta Coal is abundant in Wyoming –Lignite, a brownish, soft coal is also readily available in North Dakota

33 Typical Plains Economy Lincoln, Kansas Between Hays and Manhattan, KS

34 Canadian Great Plains Winnipeg, Manitoba Edmonton, Alberta Calgary, Alberta

35 Reading & Discussion Reading: Kansas Like a Pancake Geographers Frank and Deborah Popper of Rutgers University think large areas of the Plains should be allowed to revert to their condition prior to the arrival of Europeans—replete with large herds of bison and perhaps a few Native Americans leading traditional lifestyles. That means no more agricultural production as we know it. How might this be accomplished? Should it?

36 Related Books Capote, Truman. In Cold Blood. Vintage. –Stirring true-life tale about one of the most ghastly murders in the Great Plains. Not for the faint of heart, but VERY vivid landscape description. Cather, Willa. 1913. O Pioneers! Boston: Houghton Mifflin. –Classic novel about rural Nebraska settlement in the late 1800s and early 1900s Shortridge, James R. 2004. Cities on the Plains: The Evolution of Urban Kansas. Lawrence: University Press of Kansas –A chronicle of the founding and growth of Kansas cities from 1850 up to the present, showing how the state’s hierarchy of cities emerged from a complex series of promotional strategies Wishart, David J., ed. 2004. Encyclopedia of the Great Plains. Lincoln: University of Nebraska Press. –A groundbreaking reference book on the Great Plains with entries by 1316 authors on topics such as the region’s images and icons, climate, politics, historical development, and folklore

37 WebSources Geologic History of the Great Plains: http://www.lib.ndsu.nodak.edu/govdocs/text/greatplains/text.html Agricultural Economy: http://www.iisd.org/agri/ Early Novels about the Great Plains: http://www.willacather.org/


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