However, in the early 20th century, engineering projects including dams were created on the Missouri River, meander cutoffs, river training, bank revetments, and soil erosion control have reduced the annual transport rate to between million tons of sediment per year.
The artificial structures trap suspended sediment from travelling as it would in an un-engineered river. While average annual temperatures vary significantly between the northern and southern portions of the Interior Plains, the climate is characterized by susceptibility to droughts due to generally low annual precipitation. Due to a warm climate and evapotranspiration rates surpassing precipitation rates, the southern Interior Plains are highly susceptible to droughts and soil erosion.
A significant feature of aeolian erosion in the Interior Plains is the ubiquitous loess deposits. The deposits were placed by winds during the Pleistocene epoch. The Nebraska Sand Dunes are an example of the sand and loess during the epoch.
These dunes were formed during the Pleistocene by Northwesterly winds depositing alluvial silt and sand. That loess is so prevalent in the Interior Plains is evidence of significant aeolian erosion, as deposits are generally accumulations of wind-blown dust. The expansion of farmland eliminated many prairies containing soil-stabilizing grasses.
While droughts in the region were common, during the following drought, aeolian soil erosion was exacerbated by the reduced soil-holding prairie grasses. Dust storms eroded hundreds of millions of tons of topsoil, causing dust storms for months in the historical region known as the Dust Bowl.
On May 12, alone, an estimated million tons of wind-eroded topsoil were transported to the Atlantic ocean. In response to the rapid aeolian erosion, soil preservation methods were implemented. In the years following the Dust Bowl, 18, miles of shelterbelt were planted by the Works Progress Administration to reduce wind intensity.
Grassland and shrubland make up the largest portion of the Interior Plains within the United States, at The western margin is mainly shortgrass prairie dominated by blue grama and buffalograss. Prairies on the eastern side of the Interior Plains are dominated by tall grasses varieties including big bluestem and switchgrass.
The climate of the Interior Plains is very diverse. Weather is very extreme; up north, long winters and summers are short and cool, and down south, summers are long and hot and winters are cold, however there is very little precipitation. Air from the Gulf of Mexico flows north, colliding into air from Canada, creating sudden and violent weather, such as tornadoes, blizzards, and hailstorms.
This region provides people of Canada with wheat and grains. Indigenous people in this area still speak a number of Plains languages.
Where is it? Over a dozen states contain at least a part of this region, including Ohio, Indiana, Illinois, Kentucky, and Tennessee.
Sometimes, people make the mistake of calling the Plains the Prairie Provinces or just the Prairies. The term prairie refers to the prairie grasses that grow wild in Alberta, Saskatchewan and Manitoba. The Interior Plains landscape includes much more than just the prairie grasslands. You'll find that this entire region is generally flat in elevation. Just as in the Cordillera, the human population tends to be greater in the southern region of the plains, but you'll also notice that town and cities generally are beside a water source like a lake or river.
The Plains truly rely upon water, for the region's climate is generally dry. Water not only helps irrigate crops and livestock but it is also a source of transportation for our products, supplies, goods and services. In the past, these water routes were also major fur trading routes.
Similar to the Cordillera, these waterways also act as areas of recreation, tourism, as well, as resources like hydro-electricity for Canadians.
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