"The Beaver is a quadruped of the order Rodentia, or gnawers, the only species of its genus. It is very widely distributed, being found in the N. parts of Europe, Asia, and America, nowadays most abundantly in the N. and thinly peopled parts of North America, dwelling in communities on the banks of rivers and lakes."—(Charles Leonard-Stuart, 1911)

Beaver

"The Beaver is a quadruped of the order Rodentia, or gnawers, the only species of its genus. It is very…

A nocturnal, semi-aquatic rodent.

Beavers

A nocturnal, semi-aquatic rodent.

A type of small overflow dam.

Weir Box

A type of small overflow dam.

A small overflow dam placed in concrete.

Cippoletti Weir Set in Concrete

A small overflow dam placed in concrete.

Cross-section of New Croton dam.

Cross-section of Dam

Cross-section of New Croton dam.

Cross section of Ashoken Dam.

Dam

Cross section of Ashoken Dam.

"Battle at Dam No. 4, Potomac River, between Butterfield's brigade and a large Confederate force. A desperate and disastrous action occurred on the banks of the Potomac, at Dam No. 4. General Butterfield's brigade, consisting of the Forty-fourth New York, Seventeenth New York, Eighteenth Massachusetts and One Hundred and Eighteenth Pennsylvania, were ordered to make a reconnoissance on the Virginia side. Crossing over at Dam No. 4, which is about six miles northwest in a straight line from Sharpsburg, and eight south from Williamsport, they had hardly landed when a most murderous fire was opened upon them from an entire division of the Confederate army, every volley of which told, as they had the Federals completely under range. The Federals made a desperate resistance, but they were compelled to retire before superior numbers, and retreated in moderate order across the river." —Leslie, 1896

Battle at Dam No. 4

"Battle at Dam No. 4, Potomac River, between Butterfield's brigade and a large Confederate force. A…

"Battle at Dam No. 4, Potomac River, between Butterfield's brigade and a large Confederate force. A desperate and disastrous action occurred on the banks of the Potomac, at Dam No. 4. General Butterfield's brigade, consisting of the Forty-fourth New York, Seventeenth New York, Eighteenth Massachusetts and One Hundred and Eighteenth Pennsylvania, were ordered to make a reconnoissance on the Virginia side. Crossing over at Dam No. 4, which is about six miles northwest in a straight line from Sharpsburg, and eight south from Williamsport, they had hardly landed when a most murderous fire was opened upon them from an entire division of the Confederate army, every volley of which told, as they had the Federals completely under range. The Federals made a desperate resistance, but they were compelled to retire before superior numbers, and retreated in moderate order across the river." —Leslie, 1896

Battle at Dam No. 4

"Battle at Dam No. 4, Potomac River, between Butterfield's brigade and a large Confederate force. A…

"Battle at Dam No. 4, Potomac River, between Butterfield's brigade and a large Confederate force. A desperate and disastrous action occurred on the banks of the Potomac, at Dam No. 4. General Butterfield's brigade, consisting of the Forty-fourth New York, Seventeenth New York, Eighteenth Massachusetts and One Hundred and Eighteenth Pennsylvania, were ordered to make a reconnoissance on the Virginia side. Crossing over at Dam No. 4, which is about six miles northwest in a straight line from Sharpsburg, and eight south from Williamsport, they had hardly landed when a most murderous fire was opened upon them from an entire division of the Confederate army, every volley of which told, as they had the Federals completely under range. The Federals made a desperate resistance, but they were compelled to retire before superior numbers, and retreated in moderate order across the river." —Leslie, 1896

Battle at Dam No. 4

"Battle at Dam No. 4, Potomac River, between Butterfield's brigade and a large Confederate force. A…

This sign is used to indicate that a dam is located nearby.

Dam, Black and White

This sign is used to indicate that a dam is located nearby.

This sign is used to indicate that a dam is located nearby.

Dam, Color

This sign is used to indicate that a dam is located nearby.

This sign is used to indicate that a dam is located nearby.

Dam, Outline

This sign is used to indicate that a dam is located nearby.

This sign is used to indicate that a dam is located nearby.

Dam, Silhouette

This sign is used to indicate that a dam is located nearby.

An illustration of a simple 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, levees, and dikes are used to manage or prevent water flow into specific land regions.

Simple Dam

An illustration of a simple dam; a dam is a barrier that impounds water or underground streams. Dams…

Maximum section, Gilboa dam.

Gilboa Dam

Maximum section, Gilboa dam.

Salt lick hydraulic-fill dam, Pennsylvania.

Hydraulic-fill Dam

Salt lick hydraulic-fill dam, Pennsylvania.

Sectional view of Kensico dam.

Kensico Dam

Sectional view of Kensico dam.

Diagrammatic section of the Marjelen Lake, the Aletsch Glacier which holds it and the valley of the Viesch into which it drains when full.

Marjelen Lake

Diagrammatic section of the Marjelen Lake, the Aletsch Glacier which holds it and the valley of the…

Overall type of masonry dam.

Masonry Dam

Overall type of masonry dam.

The Red River Campaign or Red River Expedition consisted of a series of battles fought along the Red River in Louisiana during the American Civil War. Pictured here is the fleet passing the dam.

Red River Expedition

The Red River Campaign or Red River Expedition consisted of a series of battles fought along the Red…

A dam on the Salt River, located northeast of Phoenix, Arizona.

The Roosevelt Dam

A dam on the Salt River, located northeast of Phoenix, Arizona.

Rock fill and earth dam.

Sectional View of Dam

Rock fill and earth dam.

Shoshone dam.

Shoshone Dam

Shoshone dam.

A series of standard topography symbols, ranging from city to state line, commonly used in drafting.

Topography Symbols

A series of standard topography symbols, ranging from city to state line, commonly used in drafting.

"Waterwheel where the lowest flat-board is submerged in the running water. The water is often given its power from a slight inclination. This wheel is also often powered by the running water issued by a dam." —Quackenbos 1859

Undershot Wheel

"Waterwheel where the lowest flat-board is submerged in the running water. The water is often given…