Chapter Two: Geographic Patterns of the Physical Environment

"The physical environment, modified by human effort, impinges on our lives regardless of where we live" (Regional 18). Most of Nebraska's landscape is prarie; more than 2/3 of the state lies within the Great Plains and Praries region of the United States. Traveling from east to west the elevation gradually rises. The lowest area of the state is in the southeast corner and is generally 840 ft above sea level. The highest point in the state is in Kimball county at 5424 ft.

Sunset in Kimball County

Lowlands

The eastern portion of the state with its lower elevation is covered by rolling alluvial lowlands.

http://www.na.fs.fed.us/sustainability/ecomap/provinces/sec_251/251.shtm: The US Forest Service has an interesting website showing the different ecoregions of the United States; the following paragraph and two associated photos are from this site:

251H-Nebraska Rolling Hills Section

This section is level to gently rolling and hilly plains. Soil formed in glacial till on uplands or in wind-deposited loess or alluvium in floodplains along major rivers. Original vegetation was prairie cover type, most of which has been cleared for agriculture; elm-ash-cottonwood forests remain along rivers.

(Photo: J. Freeouf, USDA Forest Service)

251Ha Yankton Hills and Valleys Subsection

251Hb Lower Platte Valley Subsection

251Hc York Plains Subsection

251Hd Pawnee City-Seneca Rolling Hills Subsection

The lowlands give way to the flat plain of central Nebraska. This area is naturally treeless except for the trees that settlers and farmers planted for windbreaks. Early settlers thought Nebraska was a desert, completely inhospitable to crops and plants because of its dry grasses and treeless appearance.

This plain than becomes a tableland in the west. Throughout the north central plain area in Nebraska are rolling sand dunes covered by prarie grasses. These grasses anchor the dunes; the sandhills cover around 18,000 square miles. This region has many small natural lakes but throughout  the rest of Nebraska the lakes that exist are man-made or artificial.

"This aerial photograph of the Nebraska Sand Hills paleodesert shows a well-preserved crescent-shaped dune (or barchan) about 60 to 75 meters high. (Photograph by Thomas S. Ahlbrandt)"

http://www.cartage.org.lb/en/themes/sciences/Earthscience/Geology/Deserts/Deserts/TypesofDeserts/Paleodeserts/Paleodeserts.htm

The Missouri River forms the eastern edge of the northern boundary of Nebraska's border. It drains the entire state. Three other rivers cross the state from west to east--the Niobrara through the north, the Platte through the middle, and the Republican through the south.

To the left is a gorgeous photo of the Niobrara river.






The map below of Nebraska's rivers shows the three major rivers along with the many tributaries and smaller rivers.

Climate

Climate is the some total of day-to-day weather conditions. The two most important characteristics of climate are termperature and precipitation. "The climatic patterns that interest geographers result from the interaction of three geographic influences. The first influence is latitude--the distance north or south of the equator.

Nebraska's two largest cities: Omaha and Lincoln are located at 41 15'N and 41 03' N respectively. This means that Nebraska is significantly further from the equator than where I live in southern California. The energy is greatest when the sun can be positioned directly overhead at noon--since Nebraska is further from the equator the sun spends less hours being positioned directly overhead and there is therefore less solar energy on the average than in locations closer to the equator such as SoCal. The tilt of the Earth's axis also is respoinsible for seasonality.

The second geographic influence concerns the different ways that land and water absorb the sun's radiation.Because Nebraska is in the center of the United States and far from the Atlantic and the Pacific Oceans it has a much less temperate climate than coastal states. This tendency is continentality. "People living in the northern Great Plains or the Prarie Provinces, for example, experience annual temperature ranges close to 65C. Annual temperature differences as much as 100C...between summer and winter have been recorded" (Regions).

The third geographic influence concerns topography. Without major mountain barriers in the Midwest "air masses confront each other and produce violent weather across the region" (Regions). According to Koppen's climatic regions Nebraska lies in the dry BSk-Middle Latitude Steppe and the Humid Microthermal Dfa-Continental, no dry season

Vegetation regions are strongly related to climatic regions. Nebraska contains both a Tall grass prarie region to the west and a Short grass prarie region to the east. Because precipitation amounts were not substantial enough for tree growth much of Nebraska is covered by grasses.

Soil is made up of old rock material and organic matter. Nebraska soils are classified into two major types; most of the state falls into the Mollisols region while the western edge falls into the Aridisols region. Aridisols are generally unproductive. They get their name from the word arid which refers to the dry climate, they are low in organic content and have a low agricultural value. Mollisols are more productive. They are "midlatitude grassland soils of semiarid and subhumid climates. These soils are characterized by thick dark brown or black A-andB-horizons, loose texture and high nutrient content. They are among the most naturally fertile soils in the world and produce most of North America's cereals" (Regions).

"Holdrege soils are extensive, making up about 1.8 million acres in south-central Nebraska. Most areas of these soils are used for crops, pasture, or rangeland. Corn, soybeans, and small grain are the main crops grown under dryland conditions. Many areas are irrigated. "

http://urbanext.illinois.edu/soil/st_soils/ne_soil.htm

Mineral Fuels

Coal, oil and natural gas come from sediments formed during the Carboniferous period. The Great Plains region of the United States contains many areas where these resources may be found. Oil has been found in the western portion of Nebraska and in a smaller area along the southern border of the state.

Drilling for oil in Nebraska

In the southeastern corner of Nebraska Bituminous and subituminous coal fields have been found. These are fields that have only recently begun to be mined. Nearby Wyoming now leads the United States in coal production.