American Falls Dam

Infobox_Dam
dam_name = American Falls Dam


caption = American Falls Dam
Location Map
official_name = American Falls Dam
crosses = Snake River
reservoir = American Falls Reservoir
locale = Eastern Idaho
maint = United States Bureau of Reclamation
length = convert|5277.0|ft|m|abbr=on
height = convert|103.5|ft|m|abbr=on
width = convert|42.5|ft|m|abbr=on
began = 1976
open = 1978
cost =
reservoir_capacity = 1,671,300 acre-ft (2.06 km³) [ [http://www.usbr.gov/dataweb/dams/id00274.htm United States Bureau of Reclamation] ]
bridge_id = ID00274
map_cue =
map_

map_text =
map_width =
coordinates = coord|42|46|51|N|112|52|32|W|region:US_type:landmark [Gnis3|397375 USGS Place names] ]
extra =

The American Falls Dam is a concrete gravity-type dam located near the town of American Falls, Idaho, on the Snake River. The dam and reservoir are a part of the Minidoka Irrigation Project on the Snake River Plain and are used primarily for flood control, irrigation, and recreation. When the original dam was built by the Bureau of Reclamation, the residents of American Falls were forced to relocate three-quarters of their town to make room for the reservoir. [cite web
url = http://www.idptv.state.id.us/buildingbig/dams/americanfalls.html
title = American Falls Dam
accessdate = 2007-03-30
last = Macaulay
first = David
date = 2000
work = Building Big (Television Program)
publisher = WGBH Boston] A second dam was completed in 1978 and the original structure was demolished.

Geology

A lava dam created a broad shallow lake in the area of the Raft River during late Pliocene time, over one million years ago. Much of the basin filled with fine sand, silt, and gravel; then the dam was breached and the lake drained. These sediments (called the Raft Formation) lie beneath most of the present-day American Falls Reservoir. At other times the Snake River was dammed completely by basalt flows extruded from vents. One lava dam a few miles downstream from the present American Falls Dam formed a reservoir in which more than convert|80|ft|m of sediments (clay, silt, and sand) were deposited. This series of basalt flows and original sediments were covered by the new lake bed sediments and are named the Snake River Group and the American Falls Lake Beds. These events occurred up until the late Pleistocene, less than one million years ago. The Snake River has continued to erode its channel in the basalt and modify the lake bed sediments until the present time. cite book
last = Castelin
first = Paul M.
title = Water resources of the Aberdeen – Springfield area, Bingham & Power Counties, Idaho
url = http://www.idwr.idaho.gov/hydrologic/info/pubs/wib/wib36-wr_aberdeen-springfield_area.pdf
accessdate = 2007-04-01
series = Water Information Bulletin
year = 1974
month = May
publisher = Idaho Department of Water Administration
location = Boise
oclc = 3186303]

Geography

s about 50 ft (15 m) in several 6-10 ft. drops over highly jointed basalt. [cite book
last = Conley
first = Cort
authorlink =
coauthors =
title = Idaho for the Curious
publisher = Backeddy Books
date = 1982
location = Cambridge, Idaho
pages = p.261
isbn = 0-903566-3-0] The final drop is about a convert|15|ft|m|abbr=on plunge.

1880-1925

The city of American Falls was first platted in the early 1880s. It was named for the waterfall on the Snake River near the settlement. During the last part of the 19th century, privately financed irrigation canals were created to sustain the emerging agriculture industry in southern Idaho and other parts of the west. The Carey act (1894) paved the way for private investment in irrigation projects. By 1895, the American Falls irrigation project came before the Idaho State Land Board. In 1902 the National Reclamation Act was signed into law and federal funds from the sale of public lands became available to create and maintain irrigation projects in the Western United States. The first power plant was built in 1902 on the falls.

Damming the rivers became the preferred method for harnassing the abundant water of the western rivers. cite news
first=Sherl L.
last=Chapman
title=Irrigated Agriculture Idaho's Economic Lifeblood
publisher=Idaho Water Users Association
url =http://www.iwua.org/history/idhistory.html
accessdate = 2007-04-01] The reservoirs could then provide year-round downstream irrigation via canals, even during traditional low water times.

The use of eminent domain by the government to appropriate the original townsite in 1923 resulted in several lawsuits. One in particular, "BROWN v. U S, 263 U.S. 78 (1923) " allowed that the property valuation should include the value of the streets and improvements which would need to be replaced in the substitute site. cite news
title= BROWN v. U S, 263 U.S. 78 (1923)
date=1923-11-12
publisher=Supreme Court of the United States
url =http://supreme.justia.com/us/263/78/case.html
accessdate = 2007-03-31]

1925-1960

The first dam at American Falls was begun in 1925 by the Bureau of Reclamation and was completed in 1927. The river was temporarily impounded while the new concrete structure was put in place. The Oregon Short Line Railroad bridge over the river had to be raised to allow for crossing the new reservoir. cite news | first= | last= | coauthors= | title=Construction of the American Falls Dam | date=2002 | publisher= | url =http://imnh.isu.edu/digitalatlas/geog/rrt/part6/chp21/154155.htm | work =Digital Atlas of Idaho | pages = | accessdate = 2007-03-31 | language = ] This dam was designed by Frank A. Banks. [The United Press. Builder of Grand Coulee To Retire and Live Near It. "The New York Times", September 12 1950.]

1960-1978

The existing dam is the second structure to be called the American Falls Dam. Core samples taken in of the concrete of the original structurecite news | title= Minidoka project' | date=1998 | publisher= Bureau of Reclamation| url =http://www.usbr.gov/dataweb/html/minidoka.html | accessdate = 2007-04-01] , had deteriorated so a second dam was built just downstream in 1978. Replacement of the original dam was authorized by a congressional act of December 28, 1973 (87 Stat. 904, Public Law 93-206) cite news | first= | last= | coauthors= | title=A act to authorize the Secretary of the Interior to convey certain facilities of the Minidoka project to the Burley Irrigation District, and for other purposes | date=1997 | publisher=105th Congress | url =http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=105_cong_reports&docid=f:sr131.105.pdf | work = | pages =p.6 | accessdate = 2007-03-31 | language = ]

When the second dam was planned, members of the Shoshone and Bannock communities opposed expansion as it would further flood the lands of the Fort Hall Bottoms. Native Americans have inhabited this region for at least 10,000 years and the area is an important resource for them. Many scientists were opposed as well because of the loss of natural habitat and access to fossil records of the Bottoms. [cite journal
last = Nelson
first = Bryce
date = 1968
title = Expansion of Idaho reservoir: Indians, scientist on the warpath
journal = Science (New Series)
volume = 159
issue = 3811
pages = 173–176
issn = 0036-8075
doi = 10.1126/science.159.3811.173
pmid = 5634906]

External links

* [http://www.usbr.gov/dataweb/dams/id00274.htm American Falls Dam at US Bureau of Reclamation]
* [http://www.idptv.state.id.us/buildingbig/dams/americanfalls.html American Falls Dam at Idaho Public TV]
* [http://www.zebpalmer.com/2006/06/09/teton-dam-failure-actual-data-for-american-falls/ Data from American Falls Dam (downstream) from the Teton Dam Failure]

References