What is an Earth Dam?
An earth dam is a dam built with highly compacted earth. This dam is classified as a type of embankment dam, being built in the shape of an embankment or wedge which blocks a waterway. These dams have been built by various human societies for centuries, and they continue to be produced in some regions of the world when they appear to be suitable for the location and intended use.
Earth dams can be very cost effective to build, which makes them appealing in some regions of the world. They can be made with local materials, cutting down on the expenses involved in acquiring and transporting materials to the dam site. In addition to earth, earth dams also often contain rock, and may be filled with a core of rock. Clay is another building material utilized in earth dams.
The design of an earth dam may be solid and consistent all the way through, or it may include layers of material. Layered materials may create an avenue for drainage which is designed to relieve pressure in emergencies. The weight of the dam as a whole creates a tight seal which secures the bottom and sides of the dam, and the pressure of the water behind the dam can also act to seal the dam in place.
Earth dams can be a safety issue. If the earth dam is overtopped, it can erode the dam, making it weak and prone to failure. Repeated overtoppings can eventually result in a catastrophic collapse of the dam. Earth dams can also experience seepage and structural failure caused by poor engineering and planning. If an earth dam fails, the water behind it will be rapidly released, and the force of the water can be highly destructive.
An earthfill dam, like other types of dams, benefits from routine inspection and maintenance. Inspections ensure that any problems with the dam are identified in the early stages, so that they can be addressed before the dam fails. Maintenance keeps the dam in good condition, reducing the risk of a catastrophic failure which could lead to loss of life and financial losses in communities located below the dam.
Earth dams can be used in the generation of hydroelectric power, for the purpose of containing water in a reservoir to secure the water supply, and in flood control. Numerous designs can be used, and software programs designed for engineering earth dams can be utilized to test possible scenarios to confirm that the earth dam will be safe once it is finished.
@ Babalaas & Fiorite- I have lived in Waterbury Vermont for about ten years and we have had problems with dam safety on the towns earth and stone dam for as long as I can remember. To be fair, most of the issues with the dam are the result of poor engineering when the dam was originally built, and now the dam is completely safe. It was enough of a danger though that the 900 acre reservoir that was behind the dam had to be drained for a couple years until new systems were installed to deal with seepage.
From what I understand, the dam had improper drainage, so there was seepage at the toe edge of the dam. Now that the dam is fixed, it is a beautiful dam. It’s about a quarter mile long, and you can walk down the reservoir side embankment to swim and fish. I am glad that the dam is safe again because I would have to agree with Fiorite that living just below the dam is a little nerve racking when there are problems with the dam's structure.
@ Fiorite- The reality is quite the contrary to your assumptions. The design of a dam or levee is dependent on the engineering behind it. A soundly engineered earth dam can hold up without a problem for thousands of years. A perfect example of this is the earth and rockfill Cornalvo dam in Extremadura, Spain. The Romans built this dam almost two thousand years ago, and it is still in use as I write this. The dam is a work of architectural art.
At the core of this dam is a set of three rock walls that run the distance of the dam. Topping these three rock meridians is earth fill that slopes gently on the upstream side of the dam. The downstream side of the dam is also filled with gravel with a steeper slope. The dam is thick, but not very tall. The design is very strong, and as I said, it is still in use thousands of years later.
It seems like Earth fill dams would be dangerous. I wonder how susceptible they are to dam breaks during floods. I would not want to live downhill from an earth dam.
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