Dam Construction Overview
What is Dam Construction?
A dam is a structure built across a river, a stream, or an estuary to store water. Dams play a critical role in states like California, with more than 1,500 dams, where many urban areas and vast agricultural industries depend on extensive dam networks.
What Problems It Solves:
While vast water sources surround the earth, there’s a growing scarcity of freshwater resources. The scarcity is expected to grow more by 2050 when the world population is between 9.4 and 10.2 billion.
This data shows the apparent mismatch between the available water and the demand, especially with growing industrial and agricultural requirements. Dams address this problem by ensuring a constant water supply.
In addition to reserving water, dams can also be used for:
- Hydropower generation
- Flood control
- Water storage
- Debris control
Images of Dam Construction
Advantages & Disadvantages of Dam Construction
The advantages of a dam include:
- Dams reduce the emission of greenhouse gases like Carbon Dioxide
- Provide clean water for consumption
- You can use them for recreation purposes like kayaking, skiing, and boating
- To store mine tailings
- For irrigation
The disadvantages of a dam include:
- Vast amounts of land are used to construct dams, leading to submergence problems
- Risk of dam failure due to neglect, faulty designs, and earthquakes
- Long-standing water replaces flowing water (rivers, streams)
Dam Construction Process
As highlighted earlier, dams are constructed across rivers to create reservoirs. Sometimes they are built across valleys with small streams or dry valleys to create a storage area for water channeled elsewhere. Here’s the step-by-step process on how to build a dam.
Divert the Water
Diverting the water is the first and the most important step, whether you’re building a dam or a pond. You must divert the stream or river to create a dry area for dam construction. If the site has soft rocks, you can excavate them to form a route and blast harder rocks using explosives.
If the dams sit across wide rivers, a dry construction forms on one side of the river and the other left open for water to flow. This construction happens because the vast amounts of water make it challenging to construct a separate channel for diverting water.
Lay the Foundation
Builders construct dams on solid foundations made of soil or rocks. The foundations must be strong enough to carry the weight of the dam and withstand water pressures.
Pour the Concrete
If building a concrete dam, there are two ways of pouring concrete. The first involves pouring a wet mixture of concrete into formwork and drying it before pouring another layer. Spread each layer to raise the dam to the desired height.
The second method involves laying thin layers of earth fill and compacting them with rollers. Dams constructed using this method are called embankment dams and are often used to retain sedimented waste from industrial and mining activities.
Consider the economics of constructing a dam throughout the process. All the construction materials must be within reach. Essential materials for dam construction include:
Companies or individuals planning to construct dams must obtain a permit from the commissioner. They must fill in a Permit Application Form for Inland Water Resources Division Activities and provide the following supporting documents:
- Plans and specifications to describe the work
- Engineering design reports
- Environmental reports
- Dewatering and water handling plans
- Emergency operations plan
- Operations and maintenance plan
Dam construction disrupts the natural flow of water and the geographical structure of the river or stream. As such, the dam is bound to experience several challenges during and after construction. They include:
- Slope instability: The sudden release of large masses of material can cause instability
- Sedimentation: The movement of large chunks of soil alters the chemical and mechanical composition of the materials making up the reservoir banks, increasing erosion and the likelihood of experiencing landslides
- Induced earthquakes: The weight of the reservoir can increase pressure at epicentral depths triggering fault activity which can cause an earthquake
Questions To Ask Contractors
The dam constructed should be safe enough to store water for a long time. Contractors and design engineers work together to ensure the integrity of the structure at reasonable costs. When hiring any of these experts, it’s essential to ask the following questions:
- How do they determine the best place to build a dam?
- What do they look for when inspecting the site before construction?
- What are the parameters used to determine the site selected is suitable for dam construction?
- What are the steps they take to prevent seepage?
- How do they ensure slope stability?
Different Types of Dam Construction
You can classify dams according to the construction method, materials used, how the dam resists water pressure, the slope or cross-section of the dam. They include:
- Embankment dams: It’s also called a rockfill or earth-fill dam, depending on whether you make it from dumped rock or compacted earth.
- Concrete gravity dams: This type is the most common, and you can construct it from vertical concrete blocks with flexible seals between them.
- Arch dams: Another type of concrete dam that you can construct using layers of thin vertical blocks joined together.
- Buttress: It’s a gravity dam whose amount of concrete used for construction is reduced significantly.
Alternative Solutions to Dam Construction
Besides the apparent advantages of dams, they present some negative externalities that affect the ecosystem. Sometimes, it’s beneficial to look into alternatives to weigh the advantages and disadvantages of each. Here’s an overview of some of them:
|Service vs Service||Advantages||Disadvantages|
|Dams vs Water Recycling|
Dams, compared to water recycling:
Dams, compared to water recycling:
|Dams vs Groundwater Recharging|
Dams, compared to groundwater recharging:
Dams, compared to groundwater recharging:
Costs of Dam Construction
So, how much money does it cost to build a dam? The truth is, it’s challenging for contractors to determine the actual cost. Instead, they use estimates and compare them with the actual costs once you complete the project.
The dam cost is a function of a range of factors, including the dam’s size, the amount of preparation required to set it up, and whether the contractor needs to enlist the help of experts.
Bid & Buying Solicitation
If the primary objective is to build a dam on a small budget, the competition can be incredibly stiff. Therefore, you want to choose a bidder who can deliver the best quality even at a low budget.
It doesn’t mean you shouldn’t be cautious when constructing a large dam. It would help if you solicited help from experts and tools like Marine Matcher.
DIY Solutions for Dam Construction
Dam construction seems a tad complex, especially if you’re not conversant with this field. However, with a simple DIY guide, you can learn how to build a pond dam, how to build a natural dam, how to build a farm pond dam, or how to build a dam in a creek:
- Identify the water source feeding water to your pond or farm. A dam should be constructed where the water source meets the edge of the pond
- Arrange large rocks horizontally at least six feet from where the source of water meets the edge of the pond to divert the water
- Dig a trench (2×2) at the identified construction area
- Fill the channel with large rocks. They act as the foundation for the dam and withstand strong water currents
- Use 1-foot high stones to cover the foundation
- Look for long branches and anchor them downwards behind the dam to increase stability
- Use small rocks to cover the branches and as many open spaces as possible
- Add a layer of small stones, large stones, and tree branches until you achieve the desired dam height
Frequently Asked Questions
In a DIY dam construction, the best way to prevent leaks is to replace wooden log supports with bricks. But if avoiding leaks in large dams, it’s best to employ any of the following solutions:
- Use concrete linings
- Polymer plugs
- Prefabricated lining membranes
- Compacted earth clay linings
- Bentonite wet or dry blankets
- Bituminous coatings
The best way to prevent water from blowing out is to dig out a large reservoir and a wall to surround it.
Large boulders go a long way in covering most of the dam. And if you want to create a waterproof layer, spread a sheet of tarp on top.
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