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Hydraulic Structures

An extensive range of weir, sluice, orifice and bridge types, and control rules, enable you to accurately model the impact of structures and their operation on flows and water levels.

Water levels are often influenced significantly by weirs, sluices, bridges and other structures within the watercourse. The normal river equations (Saint-Venant equations) are not always appropriate for application to these structures.


Flood Modeller’s industry-leading 1D river solver includes more than 40 hydraulic structure units. Each of these is configured to apply theory applicable to the specific structure type, enabling you to always create appropriate representations of these features within your models.

Flood Modeller provides ten different weir types, radial and vertical sluice gates, circular or rectangular orifices and three different bridge types. Additionally, selected structures can be configured with automatic operation that incorporates logical control rules. These can activate different operating modes as user defined trigger points are reached in your model simulations.

There are many other units available to help incorporate other hydraulic effects and processes within your models. These include reservoir, manhole, pond, gauge, blockage, breach, pump and many more.

When defining your model in Flood Modeller, you are not just limited to applying each structure in isolation. They can be combined in parallel or in series, enabling representations of scenarios such as; flows under a road bridge coupled with flooding over the roadway or multiple parallel sluice gates all with independent operating rules.


If you need to model flow through a culvert, orifice or weir, and don't require a full 1D river network, use Flood Modeller’s automated structure wizard. This tool is designed to automatically add these units to your 2D domain and simplify your model build. Additionally, it enables you to customise the culvert structures design based on guidelines set by the Construction Industry Research and Information Association (CIRIA), a neutral, independent and not-for-profit body.

Levee types structures can now be included in 1D River cross sections. When present the 1D solver will calculate different water levels across a single 1D section; for left bank, right bank and main channel. This enables 1D River sections to more accurately represent extended sections which can contain lower lying areas disconnected from the main channel. With levee markers in place these disconnected areas will only become wet after water levels exceed the river bank heights, instead of a single 1D water level being calculated and applied across the entire section.

1D River cross section plotting tool has also been enhanced to display left, right and main channel water levels for cross sections containing levees. All three water level datasets can also be animated in cross section charts.

Logical rules

The 1D river solver includes a Rules unit which can represent a generalised logical controller, where output variables are set according to user-defined logical rules.


By defining a series of rules, you can precisely control the behaviour of an associated structure during a simulation. Typical uses for rules include controlling the gate opening of a sluice according to conditions within the remainder of the network; turning a pump on or off according to levels and flows at local or remote point in the model; and directly setting an abstraction depending on hydraulic conditions at specific location.

Flood Modeller provides a wide-range of logical rule options. They can include conditions that depend on arithmetic or logical conditions and/or the status of certain hydraulic variables within the hydraulic network.

For most cases, operational rules will be contained in the main Flood Modeller data file. For greater flexibility or to benefit real-time operational use the operational rules can be defined within a separate data file.

Schedule a 30 minute Flood Modeller demo

If you're new to Flood Modeller, request a live demo to find out more about the available structures and how you can apply the software on your projects.

Laptop with software screenshot (Forsyth
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