Wikipedia source excerpts
ilians do not function as active duty military and are not required to be in active war and combat zones; however, volunteer (with pay) opportunities do exist for civilians to do so.
The day-to-day activities of the three mission areas are administered by a lieutenant general known as the chief of engineers/commanding general. The chief of engineers commands the Engineer Regiment, comprising combat engineer, rescue, construction, dive, and other specialty units, and answers directly to the chief of staff of the Army. Combat engineers, sometimes called sappers, form an integral part of the Army's combined arms team and are found in all Army service components: Regular Army, National Guard, and Army Reserve. Their duties are to breach obstacles; construct fighting positions, fixed/floating bridges, and obstacles and defensive positions; place and detonate explosives; conduct route clearance operations; emplace and detect landmines; and fight as provisional infantry when required. For the military construction mission, the chief of engineers is directed and supervised by the Assistant Secretary of the Army for installations, environment, and energy, whom the President appoints and the Senate confirms. Military construction relates to construction on military bases and worldwide installations.
On 16 June 1775, the Continental Congress, gathered in Philadelphia, granted authority for the creation of a "chief engineer for the Army". Congress authorized a corps of engineers for the United States on 1 March 1779. The corps as it is known today came into being on 16 March 1802, when the president was authorized to "organize and establish a Corps of Engineers ... that the said Corps ... shall be stationed at West Point in the State of New York and shall constitute a Military Academy." A Corps of Topographical Engineers, authorized on 4 July 1838, merged with the Corps of Engineers in March 1863.
Civil works are managed and supervised by the assistant secretary of the Army. Army civil works include three U.S. Congress-authorized business lines: navigation, flood and storm damage protection, and aquatic ecosystem restoration. Civil works is also tasked with administering the Clean Water Act Section 404 program, including recreation, hydropower, and water supply at USACE flood control reservoirs, and environmental infrastructure. The civil works staff oversee construction, operation, and maintenance of dams, canals and flood protection in the U.S., as well as a wide range of public works throughout the world. Some of its dams, reservoirs, and flood control projects also serve as public outdoor recreation facilities. Its hydroelectric projects provide 24% of U.S. hydropower capacity.
The National Defense Act of 1916 authorized a reserve corps in the Army, and the Engineer Officers' Reserve Corps and the Engineer Enlisted Reserve Corps became one of the branches. Some of these personnel were called into active service for World War I. An example of this was the 510th and 511th Engineer Service Battalions. These two military units were organized at Camp Lee, Va, and consisted of black soldiers (draftees), white officers, and non-commissioned officers.
From the beginning, many politicians wanted the Corps of Engineers to contribute to both military construction and civil works. Assigned the military construction mission on 1 December 1941, after the Quartermaster Department struggled with the expanding mission, the Corps built facilities at home and abroad to support the U.S. Army and Air Force. During World War II the USACE program expanded to more than 27,000 military and industrial projects in a $15.3 billion mobilization effort. Included were aircraft, tank assembly, and ammunition plants; camps for 5.3 million soldiers; depots, ports, and hospitals; and the rapid construction of such landmark projects such as the Manhattan Project at Los Alamos, Hanford and Oak Ridge among other places, and the Pentagon, the Department of Defense headquarters across the Potomac from Washington, DC.
In civilian projects, the Corps of Engineers became the lead federal navigation and flood control agency. Congress significantly expanded its civil works activities, becoming a major provider of hydroelectric energy and the country's leading provider of recreation. Its role in responding to natural disasters also grew dramatically, especially following the devastating Mississippi Flood of 1927. In the late 1960s, the agency became a leading environmental preservation and restoration agency.
In 1944, specially trained army combat engineers were assigned to blow up underwater obstacles and clear defended ports during the invasion of Normandy. During World War II, the Army Corps of Engineers in the European Theater of Operations was responsible for building numerous bridges, including the first and longest floating tactical bridge across the Rhine at Remagen, and building or maintaining roads vital to the Allied advance across Europe into the heart of Germany. In the Pacific theater, the "Pioneer troops" were formed, a hand-selected unit of volunteer Army combat engineers trained in jungle warfare, knife fighting, and unarmed jujitsu (hand-to-hand combat) techniques. Working in camouflage, the Pioneers cleared jungle, prepared routes of advance and established bridgeheads for the infantry, as well as demolishing enemy installations.
Five commanding generals (chiefs of staff after the 1903 reorganization) of the United States Army held engineer commissions early in their careers. All transferred to other branches before being promoted to the top position. They were Alexander Macomb, George B. McClellan, Henry W. Halleck, Douglas MacArthur, and Maxwell D.
The General Survey Act of 1824 authorized use of army engineers to survey roads and canals. The next month, an act to improve navigation on the Ohio and Mississippi rivers initiated the Corps of Engineers' permanent civil works construction mission. Although the 1824 act to improve the Mississippi and Ohio rivers is often called the first rivers and harbors legislation, the act passed in 1826 was the first to combine authorizations for both surveys and projects, thereby establishing a pattern that continues to the present day.
Survey and construction of the National Road until Federal funds were withdrawn (1838)
The 555 ft 5+1⁄8 in (169.29 m) tall Washington Monument, completed under the direction and command of Lieutenant Colonel Thomas Lincoln Casey, 1884
Construction of Fort Baldwin as part of the Harbor Defenses of Portland during the Endicott Period (1905-1912)
Panama Canal, completed under supervision of Army Engineer officers, 1914
Flood Control Act of 1936 made flood control a federal policy and officially recognized the Corps of Engineers as the major federal flood control agency
Bonneville Dam, completed in 1937
Flood Control Act of 1941, which channelized the Los Angeles River and parts of the Santa Ana River
USACE took over all real estate acquisition, construction, and maintenance for army facilities, 1941
There was no road between Costa Rica and Panama until the Corps began one in 1941–1943. The concern was access to the Panama Canal during wartime.
The Manhattan Project (1942–1946)
Planning and construction of the Pentagon, completed in 1943 just 16 months after groundbreaking
Comprehensive Everglades Restoration Plan, first authorized by congress in 1948
USACE began construction support for NASA leading to major activities at the Manned Spacecraft Center and Kennedy Space Center, 1961
King Khalid Military City 1973–1987
The Water Resources Development Act of 1986 (WRDA 86) brought major change in financing by requiring non-federal contributions toward most federal water resource projects
Cross Florida Barge Canal
Tennessee-Tombigbee Waterway
Occasional civil disasters, including the Great Mississippi Flood of 1927, resulted in greater responsibilities for the Corps of Engineers.