The Conowingo Dam (also Conowingo Hydroelectric Plant, Conowingo Hydroelectric Station) is a large hydroelectric dam in the Lower Susquehanna River. The dam, one of the largest non-federal hydroelectric dams in the US, is classified as a medium height, masonry gravity type dam. The dam is located in Maryland, spanning the Cecil and Harford county border — 9.9 miles from the river mouth at the Chesapeake Bay, about 5 miles south of the Pennsylvania border and 45 miles northeast of Baltimore. Image File history File links Conowingo_Dam_16_October_1996. ... The Susquehanna River, originally Sasquesahanough as per the 1612 John Smith map, is a river in the northeastern United States. ... Official language(s) None (English, de facto) Capital Annapolis Largest city Baltimore Area  Ranked 42nd  - Total 12,407 sq mi (32,133 km²)  - Width 90 miles (145 km)  - Length 249 miles (400 km)  - % water 21  - Latitude 37°53N to 39°43N  - Longitude 75°4W to 79°33... Exelon Corporation is a giant electricity generating and distributing company headquartered in Chicago. ... Year 1926 (MCMXXVI) was a common year starting on Friday (link will display the full calendar) of the Gregorian calendar. ... Year 1928 (MCMXXVIII) was a leap year starting on Sunday (link will display full calendar) of the Gregorian calendar. ... United States Highway 1 is a United States highway which parallels the east coast of the United States. ... Map of Earth showing lines of latitude (horizontally) and longitude (vertically), Eckert VI projection; large version (pdf, 1. ... Hydroelectric dam diagram The waters of Llyn Stwlan, the upper reservoir of the Ffestiniog Pumped-Storage Scheme in north Wales, can just be glimpsed on the right. ... This article does not cite any references or sources. ... The Susquehanna River, originally Sasquesahanough as per the 1612 John Smith map, is a river in the northeastern United States. ... Official language(s) None (English, de facto) Capital Annapolis Largest city Baltimore Area  Ranked 42nd  - Total 12,407 sq mi (32,133 km²)  - Width 90 miles (145 km)  - Length 249 miles (400 km)  - % water 21  - Latitude 37°53N to 39°43N  - Longitude 75°4W to 79°33... Cecil County is a county located in the U.S. state of Maryland. ... Harford County is a county located in the northeastern region of the U.S. state of Maryland. ... This bridge across the Danube River links Hungary with Slovakia. ... The Chesapeake Bay - Landsat photo The Chesapeake Bay where the Susquehanna River empties into it. ... Capital Harrisburg Largest city Philadelphia Area  Ranked 33rd  - Total 46,055 sq mi (119,283 km²)  - Width 280 miles (455 km)  - Length 160 miles (255 km)  - % water 2. ... Nickname: Motto: The Greatest City in America,[4] Get in on it. ...

The dam is named for the town of Conowingo, Maryland. The original location of Conowingo is now under the waters of the reservoir created by the dam. The town was relocated during construction of the dam to its present location about 1 mile northeast of the dam's eastern end. The area, as per the 1612 John Smith map, was originally known as Smyth's Fales. Original location of Conowingo Conowingo is a small community in western Cecil County, Maryland, USA. Conowingo is a Susquehannock word for at the rapids. Conowingo was originally located on the eastern bank of the Susquehanna River at the confluence of the Conowingo Creek with the river. ... John Smith (1580–June 21, 1631), was an English soldier, sailor, and author. ...

Conowingo Dam also serves as a bridge for U.S. Route 1 across the Susquehanna River. The original Route 1 crossing, Conowingo Bridge, would have been submerged after the completion of the dam, so it was demolished in 1928. The Conowingo Reservoir, and the nearby Susquehanna State Park, provide many recreational opportunities. This U.S. Highway article needs to be cleaned up to conform to both a higher standard of article quality and accepted design standards outlined in the WikiProject U.S. Highways. ... Location of the Conowingo Bridge, 1900 Several incarnations of the Conowingo Bridge crossed the Susquehanna River at the original location of Conowingo, Maryland, USA, about two miles upstream of the Conowingo Dam, which replaced it. ... Susquehanna State Park is a state park on the lower Susquehanna River north of Havre de Grace, Maryland. ...

Construction and hydroelectric power generation

On January 23, 1925, Philadelphia Electric Company awarded the construction contract for the dam to Stone & Webster of Boston^[1]. Construction of the dam started in 1926. (Abandoned railroad tracks for transporting heavy equipment to the dam site can be seen along the western shore of the river below the dam.) When completed in 1928 it was the second largest hydroelectric project by power output in the United States, behind only Niagara Falls. The dam was originally built by the Philadelphia Electric Company. Through subsidiaries and mergers, the dam is now operated by the Susquehanna Electric Company, part of Exelon Power Corporation. Year 1925 (MCMXXV) was a common year starting on Thursday (link will display the full calendar) of the Gregorian calendar. ... Exelon Corporation (NYSE: EXC) is a giant electricity generating and distributing company headquartered in Chicago. ... Stone & Webster was founded as an electrical testing lab and consulting firm by electrical engineers Charles Stone and Edwin Webster in 1889. ... Nickname: City on the Hill, Beantown, The Hub (of the Universe)1, Athens of America, The Cradle of Revolution, Puritan City, Americas Walking City Location in Massachusetts, USA Counties Suffolk County Mayor Thomas M. Menino(D) Area    - City 232. ... Year 1926 (MCMXXVI) was a common year starting on Friday (link will display the full calendar) of the Gregorian calendar. ... Year 1928 (MCMXXVIII) was a leap year starting on Sunday (link will display full calendar) of the Gregorian calendar. ... For other uses, see Niagara Falls (disambiguation). ... Exelon Corporation is a giant electricity generating and distributing company headquartered in Chicago. ...

Eleven turbine sites were constructed but only seven turbines were initially installed, driving generators each rated for 36 Megawatts. A turbine house, on the southwestern end of the dam, encloses these seven units. One additional "house" unit provides 25 Hz power for the dam's electric railroad system (identical to that used by the Pennsylvania Railroad, who had an electrified line [now under Norfolk Southern ownership] running on the eastern shore). In 1978, four higher capacity turbines were added. Each drives a 65 Megawatt generator, increasing the dam's electrical output capacity from 252 to 548 Megawatts. The four newer turbines are in the open air section at the northeast end of the power house. The generators produce power at 13,800 Volts. This is stepped up to 220,000 Volts for transmission, primarily to the Philadelphia area. The dam currently contributes an average of 1.6 billion kilowatt hours annually to the electric grid. 1893 map The Pennsylvania Railroad (AAR reporting mark PRR) was an American railroad that was founded in 1846 and merged in 1968 into Penn Central Transportation. ... Norfolk Southern Corporation (AAR reporting mark NS) NYSE: NSC is a US publicly-traded stock corporation based in Norfolk, Virginia. ...

The Conowingo Hydroelectric Station would be a primary black start power source if the regional power grid ever had a widespread emergency shutdown (blackout). Restoring power after a wide-area power outage can be difficult, as power stations need to be brought back on-line. ... Power Outage is an episode of The WB drama series, Charmed. ...

Output of 12 partially open floodgates, July 1, 2006

Image File history File linksMetadata Download high-resolution version (2560x1920, 2285 KB) Summary Conowingo Dam showing the output of only 12 flood gates, partially opened. ... Image File history File linksMetadata Download high-resolution version (2560x1920, 2285 KB) Summary Conowingo Dam showing the output of only 12 flood gates, partially opened. ... For the Manfred Mann album, see 2006 (album). ...

Flood control

The dam also has 53 flood control gates, starting at the northeastern end of the powerhouse and spanning the majority of the dam. The flood gates are operated by three overhead cranes rated for 60 tons each and built by the Morgan Engineering Company of Ohio. The cranes run on rails the length of the dam. In 1936, all the flood gates were opened. During Hurricane Agnes, in 1972, all 53 flood gates were opened, for only the second time, and explosives planted to blow a section of the weir, as the waters rose within five inches of topping the dam (a record crest of 111.5 ft^[2], or 33.98 m.) At this time, on June 24, 1972, the flow sensor in the dam recorded its record discharge of 1,130,000 ft³/s (32,000 m³/s), and the flood gauge at the dam registered a record 36.85 ft^[3] (11.23 m). On January 20, 1996, the gauge recorded its second-highest recorded crest of 34.18 ft^[4] (10.42 m). A severe ice jam also developed behind the dam on this date. The record minimum recorded discharge was on March 2, 1969, when the flow sensor registered 144 ft³/s (4.07 m³/s). Tokyo floodgates to protect from typhoon surges. ... 1936 (MCMXXXVI) was a leap year starting on Wednesday (link will take you to calendar). ... Hurricane Agnes was the first tropical storm and first hurricane of 1972 Atlantic hurricane season. ... Year 1972 (MCMLXXII) was a leap year starting on Saturday (link will display full calendar) of the Gregorian calendar. ... The bridge and weir mechanism at Sturminster Newton on the River Stour, Dorset. ... Year 1972 (MCMLXXII) was a leap year starting on Saturday (link will display full calendar) of the Gregorian calendar. ... Year 1996 (MCMXCVI) was a leap year starting on Monday (link will display full 1996 Gregorian calendar). ... For the Stargate SG-1 episode, see 1969 (Stargate SG-1). ...

Environmental impacts

The river water impounded by the dam forms the 14 mile long Conowingo Reservoir, know locally as Conowingo Pond. The reservoir is used as a drinking water supply for Baltimore and the Chester Water Authority; as cooling water for the Peach Bottom Nuclear Generating Station; and for recreational boating and fishing (like the dam itself, the launching ramps are adjacent to the Peach Bottom plant and subject to strict security measures). The area below the dam is excellent for bird watching – it attracts great blue herons and bald eagles – and for fishing (it was the northernmost point allowed by the Bass Anglers Sportsman Society (B.A.S.S.) for its 1991 BASSMasters Classic when it held the tournament on the Chesapeake Bay Watershed). In low rainfall or drought conditions, balancing the need to maintain the reservoir level with the water flow needs for the downstream ecology is one of the challenges faced by the dam operators^[5]. Drinking water Mineral Water Drinking water is water that is intended to be ingested by humans. ... Nickname: Motto: The Greatest City in America,[4] Get in on it. ... Chester is a city in Delaware County, Pennsylvania, population 36,854 at the 2000 census. ... Peach Bottom NGS, a nuclear power plant, is located 60 miles (97 km) south of Harrisburg in Peach Bottom Township, York County, Pennsylvania, on the Susquehanna River. ... Binomial name Ardea herodias Linnaeus, 1758 The Great Blue Heron, Ardea herodias, is a wading bird of the heron family Ardeidae, common all over North and Central America as well as the West Indies and the Galápagos, except in deserts and high mountains where there is no water for... Binomial name (Linnaeus, 1766) Bald Eagle range Subspecies (Linnaeus, 1766) Southern Bald Eagle Audubon, 1827) Northern Bald Eagle or Washingtons Eagle Synonyms Falco leucocephalus Linnaeus, 1766 The Bald Eagle (Haliaeetus leucocephalus), also known in the United States as the American Eagle, is a bird of prey found in North... ESPN, formerly an acronym for Entertainment and Sports Programming Network, is an American cable television network dedicated to broadcasting sports-related programming 24 hours a day. ... Fields outside Benambra, Victoria suffering from drought conditions A drought is an extended period of months or years when a region notes a deficiency in its water supply. ...

The Conowingo Dam, and to a lesser extent the Holtwood and Safe Harbor Dams further upstream, severely impacted the migratory fish species, especially American shad, that would swim up the Susquehanna River to spawn. In 1984 a fish capture feature was added at Conowingo and the Shad were trucked upstream above all three dams and released. This program ended in 1999. A fish lift was installed in 1991. All three dams completed installation of fish lifts in time for the 2000 season. During the 2000 migration season, 153,000 American shad passed through the Conowingo fish lift. "However, passage rates of shad from Conowingo to Holtwood have been only 30 to 50 percent, suggesting that fish are having difficulty moving upstream in the waters of the Conowingo pool." ^[6]. Holtwood Dam (also Holtwood Hydroelectric Dam, Holtwood Hydroelectric Plant, McCalls Ferry Dam) is the oldest of three major dams built across the lower Susquehanna River, and the middle location of the three. ... The Safe Harbor Dam (also Safe Harbor Hydroelectric Station) is the most northerly, and last constructed of three hydroelectric dams on the lower Susquehanna River. ... Binomial name Alosa sapidissima (Wilson, 1811) The American shad or Atlantic Shad (Alosa sapidissima) is a species of anadromous fish in family Clupeidae of order Clupeiformes. ... Year 1984 (MCMLXXXIV) was a leap year starting on Sunday (link displays the 1984 Gregorian calendar). ... Year 1999 (MCMXCIX) was a common year starting on Friday (link will display full 1999 Gregorian calendar). ... Pool-and-weir fish ladder at Bonneville Dam on the Columbia River Fishways, most commonly referred to as fish ladders but also known as fish passes, are structures placed on or around man-made barriers (such as dams and weirs) to assist the natural migration of diadromous fishes. ... Year 1991 (MCMXCI) was a common year starting on Tuesday (link will display the 1991 Gregorian calendar). ... Pool-and-weir fish ladder at Bonneville Dam on the Columbia River Fishways, most commonly referred to as fish ladders but also known as fish passes, are structures placed on or around man-made barriers (such as dams and weirs) to assist the natural migration of diadromous fishes. ... 2000 (MM) was a leap year starting on Saturday of the Gregorian calendar. ... 2000 (MM) was a leap year starting on Saturday of the Gregorian calendar. ...

The three dams are also involved with another ecological concern. Normally the reservoirs above each dam trap sediment and nutrients that run off from the watershed and prevent some of that from reaching the Chesapeake Bay. A recent USGS study suggest that there may be as little as 20 years left before they reach capacity and no longer function to reduce the nutrient and sediment load hitting the bay. However the scouring of major floods, and other factors, affect this. The Chesapeake Bay - Landsat photo The Chesapeake Bay where the Susquehanna River empties into it. ... The United States Geological Survey (USGS) is a scientific agency of the United States government. ...

See also

• List of dams and reservoirs of the Susquehanna River

The Susquehanna River, in the Mid Atlantic States of the USA, has a collection of dams. ...

External links

• USGS - Conowingo Dam web cam and real-time water flow data
• Thinkquest Article with interior pictures and diagrams
• NWS Flood Stage Info. for Susquehanna River at Conowingo
• Maps and aerial photos for 39°39′17″N 76°09′53″W / 39.654601, -76.164603Coordinates: 39°39′17″N 76°09′53″W / 39.654601, -76.164603
  • Street map from Google Maps, or Yahoo! Maps, or Windows Live Local
  • Satellite image from Google Maps, Windows Live Local, WikiMapia
  • Topographic map from TopoZone
  • Aerial image or topographic map from TerraServer-USA

Map of Earth showing lines of latitude (horizontally) and longitude (vertically), Eckert VI projection; large version (pdf, 1. ...

References

1. ^ PRR Chronology 1926 (citing New York Times) (PDF).
2. ^ http://www.portdeposit.org/?a=history_detail
3. ^ http://newweb.erh.noaa.gov/ahps2/crests.php?wfo=phi&gage=cnwm2
4. ^ http://newweb.erh.noaa.gov/ahps2/crests.php?wfo=phi&gage=cnwm2
5. ^ CONOWINGO POOL MANAGEMENT PLAN (PDF). Retrieved on 2006-07-22.
6. ^ http://www.shwpc.com/fishlift.html

• Exelon Conowingo Dam page.
• Fish Lift Information
• USGS Sedimentation Study

Bridges of the Susquehanna River
Upstream Norman Wood Bridge	Conowingo Dam	Downstream Millard E. Tydings Memorial Bridge