A History of Dams


Dams have existed for thousands and thousands of years. Before the concept of a dam was invented, Egypt and Mesopotamia used the innovative concept of irrigation by diverting flood waters of the Nile or Tigris rivers to follow pre-determined paths. This practice, which can be tracked as far back as 6,000 B.C., would take the flood water and use it to water crops while also preventing total flooding of one area or region in particular. 

The first dams created were gravity dams made of stone, built to divert and guide large, running bodies of water. This evidence can be tracked somewhere between 4,000-2,500 B.C. in Egypt. While the Egyptians made dams of stone, fast-forward 900 years and the Mesopotamians were building dams of soil and clay, known as earth dams. These dams were far more effective than stone dams because they were water-tight. The purpose of these particular man-made dams was two-fold: 1. reduce flooding in agricultural areas to protect crops, and 2. collect and store water for future use in dryer seasons. Dams made for these purposes are referred to as water supply dams.

With that same mindset of water-tight constructions, around 100 A.D. the Romans were using concrete and mortar in their gravity dams. This design indicates that a large slab of concrete made up the foundation, and from there mortar was used for the outer casing. The materials needed for this design prompted the invention of the arch dam. Rather than depending on bulk, arch dams were strong based on their shape, requiring fewer materials to build it due to the slim construction. By the 1700s, both arch and gravity dams were in use on a global scale. Arch dams were built in narrow gaps with plenty of rock to work with, and gravity dams were built in shallow, wider areas. 

Inspired by these original structures, engineers continued to design more improved dam designs. The arch dam prompted the multiple arch dam design, including artificial supports within the build. Artificial supports led to the next theory of the buttress dam design, using arches, domes, slabs and the like. The buttress dam was the first design which was able to store water hydropower. With the ability to collect hydropower through functioning dams, an environmentally-friendly and powerful concept was born. This source of natural power continues to grow in our current age for our modern-day needs: using hydropower to create electricity. 

The first recorded hydroelectric dam was developed in Craigside in Northumberland, England. It was used to power a single arc lamp in a citizen’s private home. 

But today, hydroelectric dams are used to power far more than just lamps.


In 1850, dams were notably popping up in California more and more. Most development of dams at that time was made to meet the needs of an ever-growing population. This boom in population was a result of the Gold Rush. However, the rest of America was not too far behind in feeling those same growing pains in their populations.

The design in wide use at this time was the arch dam design. This design was meant to stand strong against bigger forces due to water pressure. Many individuals did not understand the concept of the arch dam, and from that point history shows a need for dams to grow and adapt with technology and innovation if they were to stay relevant. 

By 1920, 40% of power produced in the United States was hydroelectric. At this point, the Federal Power Act was turned into law—this act regulated hydroelectric power stations on federal land and water. Hydroelectric power stations would continue to grow and be important for flood control, irrigation and water flow navigation. With each passing year, hydroelectric dams were being developed on a larger scale. 

The Hoover Dam was completed in 1936 and still stands as a strong national figure of hydroelectric power in use in the United States of today.


Hydroelectric stations became bigger and bigger into the 20th century. There were many advantages to communities, both economically and from the perspective of an advanced standard of living. Hydropower, growing in popularity, was often referred to as “white coal” for its abundance and sheer power. 

California serves as an indication of this change. Once the Gold Rush had passed, agriculture became the biggest focus of California. This meant greater demands for water, electricity and flood control. This demand caused private, local, state and federal agencies to all start dam projects throughout the state.

Today, the United States has over 2,000 hydroelectric power stations that supply 6.4% of the country’s total electrical production output, which is 49% of its renewable energy.

The past several two decades have been met with many serious questions, as well as competing opinions, about the efficiency of hydroelectric dams. Today, there are still many small, privately owned hydroelectric dams playing a vital role in their community’s energy needs. These citizens who privately own small hydroelectric dams often seek and require support and expertise in order to manage their dams as sustainably as possible. This need is why the American Dams project was started. 


Hydroelectricity is a renewable source of energy, powered by the sheer force and might of Mother Nature. A massive benefit of this reality is low cost operations for high-value power. 

Aside from energy production, hydroelectric dams play a very important role in flood control, irrigation and navigation of strong water sources. As growing populations increase year after year, hydroelectric dams provide renewable resources to accommodate growing population for decades to come.

Hydroelectricity also means the production of energy with reduced CO2 emissions. Hydroelectric dams do not use fuel, and so the power generation does not produce carbon dioxide. While there is some methane gas given off annually, as well as the initial carbon dioxide produced during the development of the dam itself, hydroelectricity often has the lowest lifecycle greenhouse gas emissions for any other power generator. This, most importantly, means a low impact on climate change.

Economic gains of hydroelectricity must also be considered. Hydroelectric plants are virtually unaffected by the cost of availability of fossil fuels like oil, natural gas and coal. Nor are imports needed for energy to continue flowing. The plants themselves have long and sustainable lives, anywhere from 50-100 years on average.

As well, operating costs are relatively low, as plants are automated and require very few personnel on site for normal operation to take place. This allows for federal funds to be diverted to the other areas in US communities who are in need of funding for the greater good of its citizens.

Here at American Dams, we are committed to the education of dams, as well as acting as a support system to small, private dam owners across our country. As technology grows, along with our understanding of the delicate ecosystems we live in, hydroelectricity will continue to adapt in order to benefit both citizens and America’s uniquely beautiful environments.

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Interested in more information? Please visit our “Regulatory Guidance” page for case studies, FAQs and research related to dams and their impact on our planet.