Nils F. Ambursen (February 6, 1876 – January 17, 1953) was a Norwegian-American

civil engineer A civil engineer is a person who practices civil engineering – the application of planning, designing, constructing, maintaining, and operating infrastructure while protecting the public and environmental health, as well as improving existing i ...

and

inventor An invention is a unique or novel device, method, composition, idea, or process. An invention may be an improvement upon a machine, product, or process for increasing efficiency or lowering cost. It may also be an entirely new concept. If an ...

. He was the founder of Ambursen Hydraulic Construction Company and was known for his influential

dam A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aqua ...

designs in the early 20th century.

Early life and education

Ambursen was born at

Fredrikstad Fredrikstad (; previously ''Frederiksstad''; literally "Fredrik's Town") is a List of cities in Norway, city and Municipalities of Norway, municipality in Østfold Counties of Norway, county, Norway. The administrative centre of the municipal ...

Østfold Østfold () is a county in Eastern Norway, which from 1 January 2020 to 31 December 2023 was part of Viken. Østfold borders Akershus and southwestern Sweden (Västra Götaland County and Värmland), while Buskerud and Vestfold are on the other ...

Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of ...

and was educated at the Telemark Civil Engineering College (''Telemark ingeniørhøgskolein'') in

Skien Skien () is a municipality in Telemark county, Norway. It is located in the traditional district of Grenland, although historically it belonged to Grenmar/Skiensfjorden, while Grenland referred the Norsjø area and Bø. The administrative ...

Telemark Telemark () is a Counties of Norway, county and a current electoral district in Norway. Telemark borders the counties of Vestfold, Buskerud, Vestland, Rogaland and Agder. In 2020, Telemark merged with the county of Vestfold to form the county o ...

. Ambursen came to the United States by the age of 21.

Career

Working for the B. F. Sturtevant Company in

Hyde Park, Boston Hyde Park is the southernmost neighborhood of Boston, Massachusetts, United States. Situated 7.9 miles south of downtown Boston, it is home to a diverse range of people, housing types and social groups. It is an urban location with suburban ch ...

Massachusetts Massachusetts ( ; ), officially the Commonwealth of Massachusetts, is a U.S. state, state in the New England region of the Northeastern United States. It borders the Atlantic Ocean and the Gulf of Maine to its east, Connecticut and Rhode ...

, in 1903, Ambursen developed an innovative

concrete slab A concrete slab is a common structural element of modern buildings, consisting of a flat, horizontal surface made of cast concrete. Steel- reinforced slabs, typically between 100 and 500 mm thick, are most often used to construct floors and ...

and

buttress dam A buttress dam or hollow dam is a dam with a solid, water-tight upstream side that is supported at intervals on the downstream side by a series of buttresses A buttress is an architectural structure built against or projecting from a wall which ...

for an industrial client in

Theresa Teresa (also Theresa, Therese; ) is a feminine given name. It originates in the Iberian Peninsula in late antiquity. Its derivation is uncertain, it may be derived from Classical Greek, Greek θερίζω (''therízō'') "to harvest or rea ...

New York New York most commonly refers to: * New York (state), a state in the northeastern United States * New York City, the most populous city in the United States, located in the state of New York New York may also refer to: Places United Kingdom * ...

. Ambursen's design was for a

requiring minimal buttress thickness in which the upstream part is a relatively thin flat slab typically made of reinforced concrete. Ambursen's concrete-slab-and-buttress design used far less material than a traditional

gravity dam A gravity dam is a dam constructed from concrete or stone masonry and designed to hold back water by using only the weight of the material and its resistance against the foundation. Gravity dams are designed so that each section of the dam is ...

making it both a significant engineering advance and cost effective for clients. Ambursen promptly filed a

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an sufficiency of disclosure, enabling discl ...

on his own behalf and organized the ''Ambursen Hydraulic Construction Company'', based in Boston. From 1903 through 1917, the company used the technique to construct more than one hundred dams in North America, most in

New England New England is a region consisting of six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York (state), New York to the west and by the ...

. The record-breaking La Prele Dam in

Converse County, Wyoming Converse County is a County (United States), county located in the U.S. state of Wyoming. As of the 2020 United States census, the population was 13,751. Its county seat is Douglas, Wyoming, Douglas. History Converse County was created in 1888 ...

used 43 percent less concrete than an equivalent concrete gravity dam. The structure allowed an interior hollow under the

spillway A spillway is a structure used to provide the controlled release of water downstream from a dam or levee, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure tha ...

; the 1907

Bloede's Dam Bloede's Dam was a hydroelectric dam on the Patapsco River in Maryland. Built in 1906, it was the first submerged hydroelectric plant—that is, the power plant was housed under the spillway. It was also one of the earliest dams constructed of rei ...

on the

Patapsco River The Patapsco River ( ) mainstem is a river in central Maryland that flows into the Chesapeake Bay. The river's tidal portion forms the harbor for the city of Baltimore. With its South Branch, the Patapsco forms the northern border of Howar ...

Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east ...

housed its

hydroelectric power plant Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

inside that hollow and therefore "under water". The company sued to preserve its patents fairly aggressively but with mixed success. In some cases, the Ambursen dam became a more generic "Ambursen type", for instance at the 1911 Lock and Dam No. 1 on the

Upper Mississippi River The Upper Mississippi River is the portion of the Mississippi River upstream of St. Louis, Missouri, United States, a city at the confluence of its main tributary, the Missouri River. Historically, it may refer to the area above the Arkansa ...

between

Minneapolis Minneapolis is a city in Hennepin County, Minnesota, United States, and its county seat. With a population of 429,954 as of the 2020 United States census, 2020 census, it is the state's List of cities in Minnesota, most populous city. Locat ...

and

Saint Paul Paul, also named Saul of Tarsus, commonly known as Paul the Apostle and Saint Paul, was a Christian apostle ( AD) who spread the teachings of Jesus in the first-century world. For his contributions towards the New Testament, he is generally ...

Minnesota Minnesota ( ) is a U.S. state, state in the Upper Midwestern region of the United States. It is bordered by the Canadian provinces of Manitoba and Ontario to the north and east and by the U.S. states of Wisconsin to the east, Iowa to the so ...

. Civil engineer George Freeman received his own November 1912 patent on a modified version of the concrete buttress dam used there. In 1917, Ambursen left his company, which has continued to bear his name for over a hundred years. Today perhaps fifty Ambursen-type dams from the post-

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

era stand outside the United States. The tallest example, , is the 1948 Escaba Dam (''Dique Escaba'') in Tucumán,

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

Work

Warrior Ridge Dam and Hydroelectric Plant

Ambursen's designs include: ''(all dams listed located in the United States)'' * Warrior Ridge Dam (1906) in

Huntingdon County, Pennsylvania Huntingdon County is a County (United States), county in the Commonwealth (U.S. state), Commonwealth of Pennsylvania. As of the 2020 United States census, 2020 census, the population was 44,092. Its county seat is Huntingdon, Pennsylvania, Hu ...

; "the focus of widespread attention in the engineering press" * Ellsworth Dam (1907) in

Ellsworth, Maine Ellsworth is a city in and the county seat of Hancock County, Maine, United States. The 2020 United States census, 2020 Census determined it had a population of 8,399. Named after Founding Fathers of the United States, United States Foundi ...

(1907) in Ilchester, Maryland *Ashley Dam (1907-1908; undermined 1909) on the

Housatonic River The Housatonic River ( ) is a river, approximately long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map , accessed April 1, 2011 in western Massachusetts and western Connecticut in the United ...

near

Pittsfield, Massachusetts Pittsfield is the most populous city and the county seat of Berkshire County, Massachusetts, United States. It is the principal city of the Pittsfield, Massachusetts Metropolitan Statistical Area which encompasses all of Berkshire County. Pittsfi ...

* La Prele Dam (1908–1909; refurbished in 1977, breach planned prior to spring 2025 runoff) near

Douglas, Wyoming Douglas is a city in and the county seat of Converse County, Wyoming, United States. The population was 6,386 at the 2020 United States census, 2020 census. It is the home of the Wyoming State Fair. History Douglas was platted in 1886 when the ...

Rapidan Dam The Rapidan Dam is a gravity dam, concrete gravity dam located on the Blue Earth River in Rapidan Township, Minnesota, Rapidan Township southwest of Mankato, Minnesota in the United States. The dam was constructed from 1908 to 1910 to generate h ...

(1908 - 1910) on the

Blue Earth River The Blue Earth River () is a tributary of the Minnesota River, long, in southern Minnesota in the United States. Two of its headwaters tributaries, the Middle Branch Blue Earth River and the West Branch Blue Earth River, also flow for short di ...

, Rapidan Township, Minnesota * River Mill Dam (1911) in

Estacada, Oregon Estacada is a city in Clackamas County, Oregon, Clackamas County, Oregon, United States, about southeast of Portland, Oregon, Portland. The population was 4,356 at the 2020 United States census, 2020 census, and was estimated to be 5,421 in 20 ...

; on the

National Register of Historic Places The National Register of Historic Places (NRHP) is the Federal government of the United States, United States federal government's official United States National Register of Historic Places listings, list of sites, buildings, structures, Hist ...

Powersite Dam Powersite Dam is a hydroelectric dam that went into service in 1913 in Forsyth, Missouri. It is found along the White River, and the reservoir it forms is Lake Taneycomo. It was the first hydroelectric dam built in Missouri. Designed in 1911 ...

(1911–1913) in

Forsyth, Missouri Forsyth is a city in Taney County, Missouri, United States. The population was 2,730 at the 2020 census. It is the county seat of Taney County. The town is part of the Branson micropolitan area. Forsyth is located on Lake Taneycomo on U.S. Ro ...

* Overholser Dam (1917–1918) in

Oklahoma City, Oklahoma Oklahoma City (), officially the City of Oklahoma City, and often shortened to OKC, is the List of capitals in the United States, capital and List of municipalities in Oklahoma, most populous city of the U.S. state of Oklahoma. The county seat ...

; on the

* Remmel Dam (1924) impounding Lake Catherine,

Jones Mill, Arkansas Jones Mill (also known as Jones Mills) is an unincorporated community and census-designated place (CDP) in Hot Spring County, Arkansas, United States. It was first listed as a CDP in the 2020 census with a population of 411. Jones Mill is loc ...

; on the

* Stony Gorge Dam (1926-1928) in

Glenn County, California Glenn County is a county located in the U.S. state of California. As of the 2020 census, the population was 28,917. The county seat is Willows. It is located in the Sacramento Valley, in the northern part of the California Central Valley. ...

References

External links

Introduction to Buttress Dams
*

Early life and education

Career

Work

See also

References

External links

Related reading