St. Lawrence SeawaySaint Lawrence Seaway, international waterway, 2,342 mi (3,769 km) long, consisting of a system of canals, dams, and locks in the St. Lawrence River and connecting channels between the Great Lakes; opened 1959. It provides passage for oceangoing vessels into central North America. The seaway includes a 27-ft (8-m) deep waterway, a canal, and seven locks between the port of Montreal and Lake Ontario; a 27-ft (8-m) channel and eight locks through the Welland Ship Canal; and the Sault Sainte Marie Canals and locks.

The seaway has created a fourth seacoast accessible to the industrial and agricultural heartland of North America and has brought oceangoing vessels to lake ports such as Buffalo, Cleveland, Toledo, Detroit, Chicago, Milwaukee, Duluth, and Toronto. The maximum vessel size is 730 ft (223 m) in length with a cargo capacity of 28,000 tons. The shipping season has been extended to 250 days (mid-April to mid-December) by increased use of icebreakers and air pumps to control ice formation in the locks. Iron ore, wheat, and coal are the principal cargoes carried on the seaway.

Hydroelectric facilities were integrated with the project and developed and operated by the Power Authority of the State of New York and the Hydro-Electric Power Commission of Ontario. One serious unexpected side effect of the seaway has been the introduction of invasive nonnative aquatic species, such as the zebra and quagga mussels, into the Great Lakes and from there into other inland waterways.

Vocabulary:

Lock: Manmade water “elevator” that elevates the ship to the height of the lake or canal.

Hoover Dam and Hydroelectric Power

Humans modify nature by constructing dams to drain swamps, prevent floods, and to store water for drinking and irrigation. Dams also serve to generate hydroelectric power.

Function Example

Power generation

Hydroelectric power is a major source of electricity in the world. Many countries that have rivers with adequate water flow, that can be dammed for power generation purposes. For Example, the Hoover Dam powers helps to power Los Angeles.

Water supplyMany urban areas of the world are supplied with water abstracted from rivers pent up behind low dams or weirs.

Stabilize water flow / irrigation

Dams are often used to control and stabilize water flow, often for agricultural purposes and irrigation. 

Flood prevention

Dams such as the Blackwater Dam of Webster, New Hampshire and the Delta Works are created with flood control in mind.

Land reclamation

Dams (often called dykes or levees in this context) are used to prevent entrance of water to an area that would otherwise be submerged, allowing its reclamation for human use.

Non Renewable Energy

Humans further modify the environment to provide energy for their needs. Thousands of years ago, humans discovered the power of fire to warm themselves, to cook food and heat water. This allowed humans to spread to new places where the climate was colder. Later, humans discovered they could also burn coal, whale oil, and forms of petroleum for light, heat and power. Modern society continues to depend on burning fossil fuels like coal and oil. We dig mines in the ground for coal and drill holes for oil. However, the demand for oil can have destructive effects on the environment, such as the massive leak of crude oil when an oil rig exploded in the Gulf of Mexico in 2010. It also causes air pollution.

Transportation: Railways, Highways, Airports

Advances in transportation brought about dramatic changes. The steamboat made it possible for European explores to move upstream deep in the interior section of Africa, where they now established farther flung colonial empires. The railroad likewise made it possible for American’s to settle the Far West.

Wherever steamboats and trains went, people transformed the environment by establishing ranches, farms, plantations and mines, and by building towns and cities. Later countries around the world began laying down roads and highways for automobiles and trucks. Earth’s surface has been gradually transformed by a network of roads, railroad, bridges and tunnels that connect farms, factories towns and cities.

Meanwhile, the demand for energy has led people to dig mines for coal and to drill holes for oil and natural gas. The burning of these fossil fuels by factories, homes, cars and trucks has released large amounts of pollution into the atmosphere.

Transcontinental Railroad: In 1862, the Pacific Railroad Act chartered the Central Pacific and the Union Pacific Railroad Companies, and tasked them with building a transcontinental railroad that would link the United States from east to west. Allowed for settlement to the west because people could get the things that they needed delivered by rail.

Sustainable Development

In order to solve environmental issues, many countries now seek sustainable development. This means using resources in a way that can meet future as well as present human needs. If we continue to rely on non-renewable resources and to pollute the Earth’s atmosphere, land, and water at current rates, there will not be sufficient resources available for use by future generations. To achieve sustainable development means using renewable resources at a slower rate, so that nature is able to replenish itself.

This requires that both industrialized and developing nations must find ways to achieve economic growth without the reckless, wasteful and harmful use of natural resources. Ultimately, sustainable development is the realization that, since humans depend on their physical environment, they must also act to protect that physical environment.

DeforestationDeforestation or felling trees has become a favorite activity of man to extract assorted needs- be it medicines or precious paper to waste. For obvious reasons, it is shameful to read the statistics on how discriminating man has been, especially when it comes to deforestation. Deforestation is the conversion of forested areas to non-forest land for use such as arable land, pasture, urban use, logged area, or wasteland. Deforestation can also be seen as removal of forests leading to several imbalances ecologically and environmentally and results in declines in habitat and biodiversity. Urbanization, Mining, Fires, Logging and Agricultural activities are few of the causes of deforestation.

Current Forest CoverAs of 2010, the United States had 304,022,000 hectares (751,255,000 acres) of forested lands, a number that represents one-third of the country. Of this area, 25 percent is old growth forest, 67 percent is secondary forest, and 8 percent is tree farms or plantations. The United States is frequently divided into the Northeast, Southeast and the West because of forest eco-type and historical forestry practices. These regions have 41 percent, 40 percent and 28 percent forest cover, respectively, although the West has the most acres of forested lands.Historical Forest TrendsIt is estimated that prior to European settlement, the United States. was 46 percent forested. European settlers quickly harvested much of the available timber for housing, industry, the creation of railroads and to clear land for farming. By 1907, the U.S. forest cover was reduced to 33 percent. The eastern portion of the nation

was disproportionately affected during this era because it was more heavily settled and had better agricultural soils and climate than the West. Since 1953, the trend in the northern region has been increasing forest cover while the South and West have trended level to slightly downward.Deforestation RatesThe United States lost an average of 384,350 hectares (949,750 acres) of forest each year between 1990 and 2010. A total of almost 4 million hectares (10 million acres) of timber is harvested each year, but most of that timber regenerates and remains classified as forested land, albeit at a different successional stage. So the deforestation here refers to lands that are converted from forest to some other purpose. Deforestation could increase in the future because tree pests and diseases such as bark beetles are becoming more prevalent in the face of climate change.

Commercial Agriculture

Agriculture is the growing of food. Ten thousand years ago, people in the Middle East found that if they planted seeds and watered plants, they could grow fruits, grains and vegetables. They selected certain seeds to replant in order to grow the most nourishing plants.

Crop cultivation brought about modification and manipulation of the environment to increase food production—it altered the landscape by clearing existing vegetation, and cutting the soil by tilling it. People also learned to irrigate their fields to increase their productivity. Since humans first learned to plants seeds, civilizations around the world have generally turned forests, grassland, and marshes into productive farmland.

Technology assists farmers in agriculture. The introduction of the tractor in the early 20th century transformed agriculture. Today, scientists have developed better seeds, improved fertilizers, and stronger pesticides to kill harmful insects. Farmers grow more plants with less water, land and labor.

Urbanization

People also modify nature by building TOWNS and CITIES. The first cities arose in the Middle East. By 7,000 BC the city of Jericho had 3000 residents. Sumer, the world’s earliest known civilization, began on the plants of Mesopotamian in 3500 BC. Later, ancient cities like Rome had as many as a million inhabitants.

In the middle Ages, urban centers were generally smaller. Agricultural improvements in the 1700’s, increase overseas trade, and the rise of manufacturing during the Industrial Revolution led to the rapid growth of cities. Urbanization changes he environment by concentrating thousands, even millions, of people in small, treeless areas. Cities replace open fields and forests with paved, concrete roads, and tall buildings of steel, concrete and glass.

Based on the Aerotropolis Political Cartoon, What do you think the term Urban Sprawl means?