Lock and Dam No. 9
Encyclopedia
Lock and Dam No. 9 is a lock
Lock (water transport)
A lock is a device for raising and lowering boats between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a fixed chamber in which the water level can be varied; whereas in a caisson lock, a boat lift, or on a canal inclined plane, it is...

 and dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

 located near Lynxville, Wisconsin
Lynxville, Wisconsin
Lynxville is a village in Crawford County, Wisconsin, United States. The population was 176 at the 2000 census.-Geography:Lynxville is located at ....

 and Harpers Ferry, Iowa
Harpers Ferry, Iowa
Harpers Ferry is a city in Taylor Township, Allamakee County, Iowa, United States. The population was 330 at the 2000 census.-Geography:Harpers Ferry is located at ....

 on the Upper
Upper Mississippi River
The Upper Mississippi River is the portion of the Mississippi River upstream of Cairo, Illinois, United States. From the headwaters at Lake Itasca, Minnesota, the river flows approximately 2000 kilometers to Cairo, where it is joined by the Ohio River to form the Lower Mississippi...

 Mississippi River
Mississippi River
The Mississippi River is the largest river system in North America. Flowing entirely in the United States, this river rises in western Minnesota and meanders slowly southwards for to the Mississippi River Delta at the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains...

 around river mile
River mile
In the United States, a River mile is a measure of distance in miles along a river from its mouth. River mile numbers begin at zero and increase further upstream. The corresponding metric unit using kilometers is the River kilometer...

 647.9. The lower portion of Pool 9 was formally named Lake Winneshiek
Lake Winneshiek
Lake Winneshiek is the name given to that portion of Navigation Pool 9 impounded by Lock and Dam No. 9 between the dam to 4 miles south of the city of Lansing, Iowa on the Upper Mississippi River, near Ferryville, Wisconsin. It encompasses about 6,000 acres and is part of the Upper Mississippi...

. The normal pool elevation behind the dam is 620 feet (189 m). It was constructed and placed in operation in July 1937. The site underwent a major rehabilitation from 1989 and 2006. The dam consists of concrete structure 811 feet (247.2 m) long with five roller gates
Roller dam
A Roller dam is a type of hydro-control device specially designed to mitigate erosion. They are most often used to divert water for irrigation but the largest and most notable examples are used to ease river navigation.- Use :...

 and eight tainter gate
Tainter gate
The Tainter gate is a type of radial arm floodgate used in dams and canal locks to control water flow. It is named for Wisconsin structural engineer Jeremiah Burnham Tainter....

s. Earth embankment 9800 feet (2,987 m) long with a grouted overflow spillway
Spillway
A spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically being the river that was dammed. In the UK they may be known as overflow channels. Spillways release floods so that the water does not overtop and damage or even destroy...

 1350 feet (411.5 m) long. The lock is 110 feet (33.5 m) wide by 600 feet (182.9 m) long. Lock and Dam No. 9 is located 12 miles upstream from Prairie du Chien, Wisconsin
Prairie du Chien, Wisconsin
Prairie du Chien is a city in and the county seat of Crawford County, Wisconsin, United States. The population was 5,911 at the 2010 census. Its Zip Code is 53821....

.

The Friends of Pool 9 is a nonprofit organization dedicated to keeping the pool clean, managing annual volunteer cleanups, particularly of backwaters.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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