Humans have manipulated rivers for thousands of years, but over the last 200 years dams on rivers have become rampant. Reservoirs and dams are constructed for water storage, to reduce the risk of river flooding, and for the generation of power. They are one of the major footprints of humans on Earth and change the world's hydrological cycle.
This dataset illustrates the construction of dams worldwide from 1800 to the present. We display all dams listed in the Global Reservoir and Dam Database (GRanD). It includes 6,862 records of reservoirs and their associated dams. All dams that have a reservoir with a storage capacity of more than 0.1 cubic kilometers are included, and many smaller dams were added where data were available. The total amount of water stored behind these dams sums to 6.2 km3.
The red dots indicate the newly built dams and reservoirs each year, and the yellow dots represent the dams already in place.
The dams and reservoirs do not only store water, they also trap the incoming sediment that the river transports. Consequently, much less sand and clay travels to the coast, where it would normally be depositing in the delta region. The reduced sediment load of major rivers has influenced the vulnerability of many deltas worldwide.
Educational materials have been developed for this dataset, including a few PowerPoint slides, that can be used on a supplementary screen while viewing the dataset on Science On a Sphere®. Also, a discussion-based lesson plan can be used to facilitate student learning about the economics and ecology of dams.
Lehner, B., C. Reidy Liermann, C. Revenga, C. Vörösmart, B. Fekete, P. Crouzet, P. Döll, M. Endejan, K. Frenken, J. Magome, C. Nilsson, J.C. Robertson, R. Rodel, N. Sindorf, and D. Wisser. 2011. High-Resolution Mapping of the World's Reservoirs and Dams for Sustainable River-Flow Management. Frontiers in Ecology and the Environment 9:494-502. DOI: 10.1890/100125.
C4 Systems and System Models. Students understand objects and organisms can be described in terms of their parts; and systems in the natural and designed world have parts that work together.
C6 Structures and Functions. Students observe the shape and stability of structures of natural and designed objects are related to their function(s).
C4 Systems and System Models. Students understand that a system is a group of related parts that make up a whole and can carry out functions its individual parts cannot. They can also describe a system in terms of its components and their interactions.
C3 Scale Proportion and Quantity. Students observe time, space, and energy phenomena at various scales using models to study systems that are too large or too small. They understand phenomena observed at one scale may not be observable at another scale, and the function of natural and designed systems may change with scale. They use proportional relationships (e.g., speed as the ratio of distance traveled to time taken) to gather information about the magnitude of properties and processes. They represent scientific relationships through the use of algebraic expressions and equations
C4 Systems and System Models. Students can understand that systems may interact with other systems; they may have sub-systems and be a part of larger complex systems. They can use models to represent systems and their interactions—such as inputs, processes and outputs—and energy, matter, and information flows within systems. They can also learn that models are limited in that they only represent certain aspects of the system under study.
C3 Scale Proportion and Quantity. Students understand the significance of a phenomenon is dependent on the scale, proportion, and quantity at which it occurs. They recognize patterns observable at one scale may not be observable or exist at other scales, and some systems can only be studied indirectly as they are too small, too large, too fast, or too slow to observe directly. Students use orders of magnitude to understand how a model at one scale relates to a model at another scale. They use algebraic thinking to examine scientific data and predict the effect of a change in one variable on another (e.g., linear growth vs. exponential growth).
ESS2.C The Roles of Water in Earth's Processes. Water is found in many types of places and in different forms on Earth
ESS3.A Natural Resources. Living things need water, air, and resources from the land, and they live in places that have the things they need. Humans use natural resources for everything they do.
ESS3.C Human Impact on Earth systems. Things people do can affect the environment but they can make choices to reduce their impacts.
ESS2.C The Roles of Water in Earth's Processes. Most of Earth’s water is in the ocean and much of the Earth’s fresh water is in glaciers or underground.
ESS3.A Natural Resources. Energy and fuels humans use are derived from natural sources and their use affects the environment. Some resources are renewable over time, others are not.
ESS3.C Human Impact on Earth systems. Societal activities have had major effects on the land, ocean, atmosphere, and even outer space. Societal activities can also help protect Earth’s resources and environments.
LS2.C Ecosystem Dynamics, Functioning and Resilience. When the environment changes some organisms survive and reproduce, some move to new locations, some move into the transformed environment, and some die.
LS4.D Biodiversity & Humans. Populations of organisms live in a variety of habitats. Change in those habitats affects the organisms living there
ESS2.C The Roles of Water in Earth's Processes. Water cycles among land, ocean, and atmosphere, and is propelled by sunlight and gravity. Density variations of sea water drive interconnected ocean currents. Water movement causes weathering and erosion, changing landscape features.
ESS3.A Natural Resources. Humans depend on Earth’s land, ocean, atmosphere, and biosphere for different resources, many of which are limited or not renewable. Resources are distributed unevenly around the planet as a result of past geologic processes
ESS3.C Human Impact on Earth systems. Human activities have altered the biosphere, sometimes damaging it, although changes to environments can have different impacts for different living things. Activities and technologies can be engineered to reduce people’s impacts on Earth.
LS2.C Ecosystem Dynamics, Functioning and Resilience. Ecosystem characteristics vary over time. Disruptions to any part of an ecosystem can lead to shifts in all of its populations. The completeness or integrity of an ecosystem’s biodiversity is often used as a measure of its health.
LS4.D Biodiversity & Humans. Changes in biodiversity can influence humans’ resources and ecosystem services they rely on.
ESS2.C The Roles of Water in Earth's Processes. The planet’s dynamics are greatly influenced by water’s unique chemical and physical properties.
ESS3.A Natural Resources. Resource availability has guided the development of human society and use of natural resources has associated costs, risks, and
ESS3.C Human Impact on Earth systems. Sustainability of human societies and the biodiversity that supports them requires responsible management of natural resources, including the development of technologies that produce less pollution and waste and that preclude ecosystem degradation.
LS2.C Ecosystem Dynamics, Functioning and Resilience. If a biological or physical disturbance to an ecosystem occurs, including one induced by human activity, the ecosystem may return to its more or less original state or become a very different ecosystem, depending on the complex set of interactions within the ecosystem
LS4.D Biodiversity & Humans. Biodiversity is increased by formation of new species and reduced by extinction. Humans depend on biodiversity but also have adverse impacts on it. Sustaining biodiversity is essential to supporting life on Earth
Japan built many dams already in the early 19th century.
In the U.S. East Coast, many medium-sized dams were constructed for grain milling and saw mills pretty early on.
In the 20th century, large engineering projects developed dams in more arid regions for drinking water and irrigation water storage and worldwide for electric power generation. The Hoover Dam, constructed in the 1930s on the border of Arizona and Nevada, is one example.
Most recently, large construction projects have been completed in China, including the Three Gorges Dam on the Yangtze River. The Three Gorges Dam is the world's largest hydroelectric facility.