North America - its Rivers (1971)

[Music] the rivers of North America have played a vital part in the exploration and settlement of the continent to the American Indians the rivers were natural highways highways that early Pioneers used to help settle the new world today the rivers are still heavily used for transportation [Music] but the rivers also work in other ways for man dams and giant reservoirs have been built to control the turbulent Rivers the dams generate electrical energy to run North American homes and factories the reservoirs Supply water for irrigated farming and domestic water supplies for cities most rivers of North America begin far up in the mountains or Hills with a small spring or melting Glacier as the stream flows from its source other streams and rivers its tributaries join it and increase its size a river and all its tributaries make up a river system the system drains water from the surrounding land called The River Basin the great Watershed of the continent is the Continental Divide which runs along the western cordilla mountains it determines the two great drainage directions on the west side of the Divide rivers flow into the Pacific and northwesterly into the Bearing Sea rivers on the east side of the Divide flow northeasterly into the Arctic Ocean and Hudson Bay easterly into the Atlantic and southeasterly into the Gulf of Mexico and Caribbean Sea many rivers east of the Divide are tributaries of the North American father of waters the great Mississippi Mark Twain's shining River winding here and there and Yonder a pageant of American History has passed up and down this largest river in the United States one of the largest inland waterways in the world one main source of the Mississippi is a clear little stream less than a foot deep it flows out of the Northern end of Lake atasa in Minnesota as the Great River Flows South through the Gulf of Mexico 250 tributaries pour into it draining a small part of Canada and 40% of the United States sand mud and silt are carried by the River from the Rocky Mountains from Illinois cornfields from Mississippi cotton fields and from Pennsylvania hillsides silt is deposited at the Mississippi's mouth in the Gulf of Mexico this is the Mississippi Delta new land being made by the powerful river system year after year the Great River deposits a million tons of silt a day building the Delta farther out into the Gulf the Mississippi is an important water Highway that carries more than 200 million tons of freight a year Freight from as far north as the Great Lakes coal from Pennsylvania oil from Texas a serious problem of the Mississippi is one it shares with some other rivers of North America flooding loss of life and destruction of property occur when the Mississippi breaks through its banks to combat the dangers of flooding an enormous system of man-made Banks levies has been constructed to keep the river contained flooding is also serious on the Ohio River a chief tributary of the Mississippi the two giant rivers meet at Koo Illinois for flood prevention this dangerously located city is protected by high concrete levies when the rivers rise these openings can be quickly closed to control the flooding the Ohio River's level rises sharply because its Basin has heavy spring rains and winter snows abundant rainfall and good soil make the Ohio Basin one of the rich farmlands in the United States in addition to agriculture the Ohio Basin is heavily industrialized Cincinnati is one of the many Pioneer settlements that were established when the Ohio was the Gateway to the West Cincinnati is a huge manufacturing center because of the heavy industrialization of the Basin the Ohio river is suffering from a problem common to many of the rivers of the continent pollution waste from factories and urban communities ities have turned portions of the river into open sewers pollution is also a problem of another major tributary of the Mississippi the Missouri River the Missouri's Basin is not as heavily populated as the Ohio yet River pollution comes from Farmland and from large industrial cities like Kansas City Missouri and bismar North Dakota away from the industrial areas portions of this magnificent Missouri are much as they were when it served as a route to the West the river transported leis and Clark on their exploration of the northern portion of the Louisiana Purchase they were followed by fur trading mountain men who use the river as their Highway West then in the 1840s migrating Pioneers used the Eastern portion of the Missouri before starting their Overland journey to California and Oregon today Mammoth dams and reservoirs like these at Fort peek Montana control the river and Supply hydroelectric power at the same time water is conserved for irrigated farming the shallow muddy Missouri and the deep wide Ohio and the great Mississippi make up a river system that has about 14,000 Mi of navigable waterways a contrasting river system is the mostly non-navigable real grand a shallow shifting river that forms a portion of the border between the United States and Mexico where it's called Rio Bravo Brave River in seasons of little rainfall the lower portions of the Rio Grand may run dry contributing to its shallowness is the draining of its precious water for irrigated farming the Rio Grand is a winding river that often as if by whim changes its course during its colorful history it caused boundary disputes between Mexico and the United States disputes that partly contributed to the US Mexican war in 1846 west of the Rio Grand across the Continental Divide is the Colorado River the powerful Westward rushing Colorado has for millions of years eroded its way through layer after layer of rock to produce the Grand Canyon the rapid Colorado is a beautiful River largely unspoiled and unpolluted because of the sparsity of population in its Basin the powerful Colorado drains 1/4 million square miles of mostly Barren land areas in the Colorado Basin have been changed with a construction of dams like Hoover Dam the reservoir behind the dam is Lake me one of the largest man-made bodies of water in the world the lake is increasingly used for recreation but more important water from this huge Reservoir is carried by The All-American canal and other channels to irrigate thousands of Acres of Rich crop lands in California Arizona and Mexico north of the Colorado is the Colombia River a small portion of which is in Canada from its source in the high Rocky Mountains of British Columbia the clear sparkling Columbia river runs through forested mountains of western Canada to become the greatest Waterway emptying into the Pacific Ocean the Columbia drains an area equal to the Basin of the col colado River IT Supplies vast areas of the Columbia Plateau with precious water for irrigated farming a distinction of the Columbia river is its abundance of salmon and other fish salmon can be caught so easily that the supply is decreasing Canada and the United States have jointly passed laws for controlling the fishing this hopefully will ensure preservation of salmon as a food resource the two Nations have also assisted cities and towns along the river to keep the water clean and the Colombia River which serves few large cities has not been severely polluted in addition to the Continental Divide and determining the eastwest river flow there is a subcontinental watershed generally along the Canadian United States border that separates the rivers that flow to the south from those that flow to the north the St Lawrence River a major Commerce route flows northeasterly and empties into the Atlantic the St Lawrence is the most important river of Canada since it was first seen by the French in 1535 the wide deep course of the St Lawrence has been a highway for explorers fur Traders and the colonists who came to settled Canada today the St Lawrence Seaway has made the river even more more important by creating the world's largest Inland Waterway for deep sea navigation large oceangoing ships can sail from the Atlantic into the Great Lakes a distance of 1200 miles here in Montreal the Seaway is a complex system of dams locks and reservoirs west of Montreal the river is bordered by small towns and pleasant farmlands ships proceed up River into the Great Lakes to Inland ports such as Calumet Harbor Chicago in contrast to the industrial St Lawrence Great Lakes region is the undeveloped Basin of the McKenzie river in the cold Northwest it's Canada's longest river the Mackenzie drains an area as large as both the Columbia and Colorado basins combined the McKenzie Basin is sply populated with a climate too cold for agriculture but the Basin is rich in petroleum and other minerals this cold desolate land is a new frontier which promises to become more developed and populated in the future almost as isolated as the the McKenzie is the Yukon river starting in Canada it meanders through the Klondike goldfields on its way to Alaska and the Bearing Sea the Yukon and its Basin teamed with goldry Prospectors in the late 1890s today the gold production has decreased and the area remains unsettled during the Gold Rush the Yukon was used for shipping but it's frozen for as long as 7 months each year today air and rail Transportation have made shipping by boat unprofitable on the Yukon the hundreds of rivers of North America the broad sweeping ones the shallow muddy ones the powerful rushing ones all contribute to farming Urban water supply hydroelectric power Recreation and transportation in North [Music] America