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Dam vs. Reservoir: What's the Difference?

Edited by Aimie Carlson || By Harlon Moss || Published on November 22, 2023
A dam is a barrier constructed to hold back water, while a reservoir is a storage space, often a lake, created by a dam to store water.

Key Differences

A dam is built to block the flow of water, creating a body of water behind it. On the other hand, a reservoir, formed by this blockage, serves as a storage area for the water accumulated due to the dam.
Dams are engineered structures made of earth, concrete, or other materials, designed to withstand water pressure. While, reservoirs are the resultant areas, either natural basins enhanced or entirely man-made, shaped by the dam's construction.
The construction of a dam can significantly alter the local ecosystem and river flow. However, a reservoir can provide benefits like water supply and recreation, but also impact the environment and local communities.
Dams require active management for structural integrity and water flow control. Meanwhile, reservoirs are managed for various uses such as water supply, irrigation, flood control, and recreation.
Dams have been a crucial part of human civilization for irrigation and water control. Conversely, reservoirs have also been central to societies, often becoming focal points for communities and recreation.

Comparison Chart

Primary Function

To obstruct and control water flow
To store and manage water


Built using concrete, earth, etc.
Formed by damming a water source

Environmental Impact

Alters river flow, local ecosystem
Can create new habitats, also disrupts


Structural integrity, flow control
Water quality, supply, and usage control

Cultural Significance

Integral in water management history
Often central to community and recreation

Dam and Reservoir Definitions


In colloquial use, to damn or condemn.
He dammed his luck for the unfortunate incident.


A place where fluid collects, especially in rock layers.
The oil reservoir was discovered deep underground.


To block up a stream or river.
Beavers dam streams to create ponds.


A supply or source of something.
The library was a reservoir of knowledge.


A barrier that stops or restricts the flow of water.
The Hoover Dam is a remarkable feat of engineering.


A natural or artificial lake for storing water.
The city's main water supply comes from the nearby reservoir.


An obstruction in a watercourse.
The fallen trees acted as a natural dam.


A receptacle for holding liquids.
The ink reservoir in the pen was almost empty.


A structure for controlling or holding back water.
The dam provided essential water for the nearby towns.


An artificial lake where water is stored.
They went boating on the reservoir during summer.


A barrier constructed across a waterway to control the flow or raise the level of water.


A natural or artificial pond or lake used for the storage and regulation of water.


A body of water controlled by such a barrier.


A receptacle or chamber for storing a fluid.


A barrier against the passage of liquid or loose material, as a rubber sheet used in dentistry to isolate one or more teeth from the rest of the mouth.


An underground accumulation of petroleum or natural gas.


What is a dam?

A dam is a structure built to control or stop water flow.

What is a reservoir?

A reservoir is a storage space for water, often a lake, formed by a dam.

Why are dams built?

Dams are built for water supply, flood control, electricity generation, and irrigation.

Can dams affect the environment?

Yes, dams can significantly alter local ecosystems and river flows.

How are dams maintained?

Dams are maintained through regular inspections, repairs, and monitoring of water flow.

Do reservoirs support wildlife?

Reservoirs can create new habitats for wildlife but may also disrupt existing ones.

Are reservoirs natural or man-made?

Reservoirs can be either natural or man-made, often formed by damming a water source.

Are there environmental concerns with reservoirs?

Yes, reservoirs can lead to habitat loss, sedimentation, and changes in local climate.

What is the largest dam in the world?

The Three Gorges Dam in China is currently the world's largest dam.

How does a reservoir benefit an area?

Reservoirs provide water for various uses, recreation, and can also generate hydroelectric power.

What activities can be done at a reservoir?

Activities like fishing, boating, and swimming can be enjoyed at many reservoirs.

Can dams break?

Yes, without proper maintenance and under extreme conditions, dams can fail.

What is the purpose of a dam spillway?

A spillway is designed to release excess water from a dam to prevent overflow.

Can wildlife cross a dam?

Some dams are equipped with fish ladders to allow fish to cross, but many are barriers to wildlife.

What materials are used to build dams?

Dams are constructed from concrete, earth, rock, and other materials.

How do reservoirs affect water quality?

Reservoirs can improve or degrade water quality, depending on management and environmental factors.

Do reservoirs help in flood control?

Yes, reservoirs can help manage flood risk by controlling the release of stored water.

How do dams generate electricity?

Dams generate electricity by using the water flow to drive turbines in hydroelectric power plants.

Can reservoirs dry up?

Yes, reservoirs can dry up during droughts or if water usage exceeds the replenishment rate.

Are there recreational areas near dams and reservoirs?

Many dams and reservoirs have adjacent recreational areas for public use.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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