There are around a dozen different kinds of dams. These are usually constructed using concrete, but in times past, they were made using wood, steel, and stones. Dams can hold water, produce hydroelectricity, and help to irrigate crops, although most modern dams are storage dams and are used for water storage and hydroelectricity.
Planning
Building a dam is no small feat. First, a team of civil engineers and government employees must plan the dam. These individuals will have to examine the river site and determine how long and wide the dam should be and from what materials it should be made. Most modern dams are either arch dams or gravity dams. Arch dams have a curved structure, which is compressed by the water pressure behind the dam. This design is commonly used when a tall dam must be built in a narrow gorge. Gravity dams, on the other hand, form a straight barrier across the river and have a cross section that will resist water pressure. This type of dam is unique in that water pressure actually makes the dam stronger, not weaker. In some cases, civil engineers may opt to combine both dam styles, as was done when the Hoover dam was constructed.
Diverting the Water
The engineers will also determine how to best divert the river while the dam is being built. In most cases, diversion tunnels are made so that the river will flow around the area while the dam is being constructed. Cofferdams (small dams) are built upstream and downstream so the dam construction site can be thoroughly de-watered.
Preparing the Site
After water has been cleared from the construction site, loose rock, and rubble must be removed. If the dam is to have a concrete faced rock fill, then a plinth has to be built around the upstream edge of the dam. The plinth is essentially the foundation for the dam and connects the dam to the valley walls and floor. After the plinth has been built, then the area is fully waterproofed. This is done by pumping cement grout into any cracks in the riverbed floor.
Constructing the Dam
After building the plinth and completely waterproofing the area, then the rest of the dam can be constructed. This work is done by thousands of experienced workers who are supervised by engineers who ensure that the job is done right and there are no mistakes. If the dam is meant to be a hydroelectric dam, then power stations and related structures are constructed at the same time as the rest of the dam is being built.
Releasing the Water
When the dam is completed, then the cofferdams are removed and the diversion tunnels are stopped up using a concrete plug. However, in many cases, diversion tunnels are simply sealed but not destroyed. This is done so that some water can be released through the tunnels should an emergency arise.
Dam construction has advanced greatly over the last several thousand years. In times past, it was common for dams to overflow or fall apart due to flooding or even just the continual force of the water pushing against the dam. However, as the years have gone by, engineers have learned how to build dams that are able to withstand water pressure long term and so dam collapses are a rare event indeed.
Building a dam often takes many years. Government approval is usually required and the construction company doing the work has to wait until the river is at low tide before starting construction. However, all the time and effort that goes into building a dam is well worth it, as dams provide both water and electricity to tens of thousands of people all over the world.
Author Bio
Ryan Ayers is a writer who creates content in the field of government. This article encourages further study in this are with an Online Masters in Public Administration.
Planning
Building a dam is no small feat. First, a team of civil engineers and government employees must plan the dam. These individuals will have to examine the river site and determine how long and wide the dam should be and from what materials it should be made. Most modern dams are either arch dams or gravity dams. Arch dams have a curved structure, which is compressed by the water pressure behind the dam. This design is commonly used when a tall dam must be built in a narrow gorge. Gravity dams, on the other hand, form a straight barrier across the river and have a cross section that will resist water pressure. This type of dam is unique in that water pressure actually makes the dam stronger, not weaker. In some cases, civil engineers may opt to combine both dam styles, as was done when the Hoover dam was constructed.
Diverting the Water
The engineers will also determine how to best divert the river while the dam is being built. In most cases, diversion tunnels are made so that the river will flow around the area while the dam is being constructed. Cofferdams (small dams) are built upstream and downstream so the dam construction site can be thoroughly de-watered.
Preparing the Site
After water has been cleared from the construction site, loose rock, and rubble must be removed. If the dam is to have a concrete faced rock fill, then a plinth has to be built around the upstream edge of the dam. The plinth is essentially the foundation for the dam and connects the dam to the valley walls and floor. After the plinth has been built, then the area is fully waterproofed. This is done by pumping cement grout into any cracks in the riverbed floor.
Constructing the Dam
After building the plinth and completely waterproofing the area, then the rest of the dam can be constructed. This work is done by thousands of experienced workers who are supervised by engineers who ensure that the job is done right and there are no mistakes. If the dam is meant to be a hydroelectric dam, then power stations and related structures are constructed at the same time as the rest of the dam is being built.
Releasing the Water
When the dam is completed, then the cofferdams are removed and the diversion tunnels are stopped up using a concrete plug. However, in many cases, diversion tunnels are simply sealed but not destroyed. This is done so that some water can be released through the tunnels should an emergency arise.
Dam construction has advanced greatly over the last several thousand years. In times past, it was common for dams to overflow or fall apart due to flooding or even just the continual force of the water pushing against the dam. However, as the years have gone by, engineers have learned how to build dams that are able to withstand water pressure long term and so dam collapses are a rare event indeed.
Building a dam often takes many years. Government approval is usually required and the construction company doing the work has to wait until the river is at low tide before starting construction. However, all the time and effort that goes into building a dam is well worth it, as dams provide both water and electricity to tens of thousands of people all over the world.
Author Bio
Ryan Ayers is a writer who creates content in the field of government. This article encourages further study in this are with an Online Masters in Public Administration.
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