Types of Barrage

Types of Barrage

There are a range of benefits from the construction of dams and barrage projects including economic, environmental, and social benefits. For one, they help with flood control, water supply, waste management, river navigation, and are essential for hydroelectric power. There are differences between dams and barrages. It can get confusing because both are often used interchangeably. There are also different types of barrage to consider. We’re reviewing some of the components of each below. 

Both weirs and barrages fit the spectrum of dams, but each have their own features and construction elements differ. Here’s what you can know about the different types of barrage projects and components. 

types of barrage and design

Differences in Dams, Barrages & Weirs

As a general category, a dam is defined as a barrier that is constructed across a water source. It works to create deep reservoirs of water that can be stored and used in multiple ways. A weir can have the same working components as a dam, but its uses can differ slightly. 

A weir is usually built through an open channel like a river and is built to control water flow, measure discharge, prevent flooding, and make rivers navigable. It can also be constructed using different materials such as wood, concrete, or a mixture of rocks, gravel, and boulders. 

Barrages are concrete structures that feature large gates that can control water flow. A main difference between a dam and a barrage is that in a barrage, the flow of water can be utilized for different purposes such as irrigation. Dams, on the other hand, usually have set heights within their concrete structures to contain or store water. The gates for a barrage can usually be controlled and manipulated easily. 

If we’re comparing barrages, dams, and weirs we can more easily understand their bigger picture function. A weir is intended or built to raise water level on the upstream side. Excess water flows over a weir. Barrage has gates that are adjustable and are built over a dam to maintain the water surface at different levels at different times. 

The similarities between are fairly straightforward as both are used for:

  • Controlling flooding
  • Helping to make a river navigable
  • Measuring discharge

There are also different types of barrage structures to consider when comparing these different elements. 

Different Types of Barrage Features

Weirs are built with either shutters or counter balance gates in order to maintain pond levels. There are different components in a barrage such as shutters or gates, which function to:

  • Maintain pond level
  • Raise water levels during low supplies

Shutters can be dropped down when water overflow occurs. A gated weir, on the other hand, can help construction sites raise gates during floods. 

The different types of gates for a barrage hold different functions. We’re reviewing a few below. 

Fish Ladder

A fish ladder, also known as a fishway or fish pass, is a narrow trough structure  that enables fish to pass around barriers by swimming and leaping up a series of low steps. The objective is to control water flow to encourage fish toward the ladder, but reduce water flow enough to avoid washing fish back downstream. There are also different types of fish ladders including:

  • Pool and weird
  • Baffle fishway
  • Fish lift (or elevator)
  • Rock-ramp fishway
  • Vertical-slot fish passage
  • Fish siphon
  • Fish cannon

Different types of fish species benefit from different types of fish ladders. This component of a barrage is important because fish move from upstream to downstream to search for warmer waters, or clear waters before monsoon season. 

Sheet Piles

In a barrage, sheet piles are situated both upstream and downstream of the barrage in order to reduce uplift pressure and prevent piping. Upstream sheet pile is more effective in reducing uplift while the downstream sheet pile is more effective in reducing piping. Functions of sheet piles help to protect the water structure while decreasing pressure on the barrage.

Under the base of a weir, water is constantly moving. If the hydraulic gradient gets too large, it begins to dislodge soil particles and carry them away. Unfortunately, if this erosion continues, a pipe or channel will form through the floor, which can cause weir failure. 

Inverted Filter

Inverted filters are parts of the barrage that contain coarse sand and gravel. This filter is overlaid with concrete blocks that are strong enough to keep it in place. The area between the blocks and the filter function to allow water to escape. The purpose of this filter is to examine the soil particles that escape in the seepage of water. It also helps address issues that occur with a scour

types of barrage

Different Types of Barrage & Design

There are different components that make up a barrage also determine its overall functionality. To construct a barrage, there are several factors that should be weighed, including:

  • Overall flow of river beds
  • Geology of the area
  • Regulations
  • Possible floating material during floods
  • Fish population and ecosystem

Barrages are straight structures placed perpendicularly to the flow of the water or at an angle in order to lower the water depth over the barrage. There are few types of barrage or categories to consider:

  1. Regulated Barrages – functions to keep water level stable using regulated sluiceways and gates
  2. Unregulated Barrages – does not regulate upstream water level
  3. Temporary Barrages 

Within each of these categories there are a variety of structures and design types for barrage. For example, an unregulated barrage may have features that include a main spillway, or an environmental flow spillway, an upstream tank, gravel traps and sand traps, etc. 

A barrage is a type of dam although there are few key differences that contain a number of large gates that control the passage of water. Each of the types of barrage help to address specifics of the river where they operate. These mechanical structures are extremely important for dam projects as they can determine water profiles and stabilize the upstream water levels. 

different types of barrage

Gracon LLC: Lead Dam Construction Company

Barrage construction and projects serve as a critical function for industry operations. Like weirs, a barrage serves many purposes including its function to influence water flow using adjustable gates and control water levels. Similar to weirs, different types of barrage are responsible for fish stocking, stabilization of groundwater levels, lessening the effects of river regulation that coincides with large hydro projects, and serving as a mitigation measure for larger hydropower developments. 

Gracon LLC is experienced in dam construction features and design needs. We are well versed in rehabilitation and replacement services for dam mechanical equipment of all sizes. We’re knowledgeable and experienced in proper construction and repairs of various types. For more information on our core services, contact us directly.