Environmental Engineering Reference
In-Depth Information
A canal can be created by further digging and expanding an existing stream, creating a canal from dry land
where no water source existed, or by developing a canal parallel to a stream or river. Canal size can vary from
a small irrigation ditch in the Midwestern Unites States to the immense Panama Canal in Central America, to
the series of canals in Venice, Italy. When canals are created, other waterways are affected, since the canal
must be fed by a natural source of water. In some cases, canals are also dug into wetlands. This process alters
the flow of natural waterways, removes vegetation, increases chances for erosion, and can lead to habitat frag-
mentation. Canals also can become contaminated from waste and runoff, leading to increased environmental
degradation and threats to wildlife and human health. The modification of channels can lead to impacts similar
to those of canal development. With increasing awareness of these issues and impacts, more effort is being
made to keep canals healthy, minimize environmental impact, and properly plan the construction and use of
canals and channels.
Public and Federal Lands
In the United States, land usage and the goals of land usage have changed, in part, due to human immigration
and migration. During westward expansion, people explored and settled new areas, largely in the hopes of ex-
tracting and profiting from natural resources such as gold, silver, and timber. Laws created during these times
including the Homestead Act of 1862 and the General Mining Act of 1872, focused on promoting the expan-
sion and settlement of the country.
The federal government now manages about 29 percent of the land in the United States, which is overseen by
four federal agencies: the Bureau of Land Management, the National Park Service and the Fish and Wildlife
Service in the U.S. Department of the Interior, and the Forest Service in the U.S. Department of Agriculture.
Management
Created in 1905, the U.S. Forest Service manages public lands within national forests and grasslands. Origin-
ally it was established to provide water and timber for the nation, but its role eventually expanded to include
the responsibility of managing all renewable resources found in national forests, including water, wildlife,
wood, and recreation. The National Park Service, established in 1916, manages the nation's 394 national parks,
preserving the wildlife, ecosystems, and historical value of the lands. In 1940, the Fish and Wildlife Service
was created as a result of the merging of the Bureau of Fisheries and the Bureau of Biological Survey. This
agency works to protect and conserve fish, wildlife, plants, and their habitats. The Bureau of Land Manage-
ment was created in 1946, combining the General Land Office and the U.S. Grazing Service. Its mission is to
protect resources and monitor resource use on public lands.
Gradually, the government's focus has shifted toward managing the increasing populations and establishing in-
frastructure and laws to support higher population densities while also protecting ecosystems and resources. In
1969, the National Environmental Policy Act was passed, and the law went into effect in 1970, mandating that
environmental impacts be taken into account with any federal decision. The act also established the Council on
Environmental Quality, requiring that an environmental impact statement be prepared for any action taken by a
federal agency. Also established in 1970 was the Environmental Protection Agency (EPA), with the mission of
establishing and enforcing environmental protection standards, gathering and using information pertaining to
pollution, helping others through grants and other means to reduce pollution, and working with the Council on
Environmental Quality to establish new environmental policies. Basically, the EPA writes and enforces regula-
tions based on established laws pertaining to the environment.
Wetlands
