The Art of Hydraulic Modelling

28 augustus 2018

By Rameshwari Bhoyar

Modelling- Seems a fancy term and it is, in the technical world! Every time I tell people I am into modelling I watch them double take and immediately think I walk on the ramp as hydraulic modelling is not popularly known yet. Models walking on ramp display how the clothes will look, hydraulic model shows how the water behaves/looks in the natural and built environment- i.e. water flowing through the rivers, clean water coming to our homes, wastewater discharged after the use or the waves in our shores. Hydraulic models replicate natural environment in our computers and are studied in-depth for cause and effect.

When the water is discharged from our houses, commercial premises or industries, it flows through a series of pipe networks to treatment plants, and from there to rivers or oceans. Our projects comprise of modelling the network, and the natural water bodies as per the project requirement which are analyzed, updated, and simulated for different return periods and durations. The critical duration serves as a basis for analysis and solution capacity. The flows within the model are calibrated and validated against the historical and real-time field measurements (using flow monitors for pipes, ADCPs for tide and current, depth monitors for wet wells).

Wastewater and Stormwater Pipe Network Modelling

Wastewater and stormwater modelling deals with pipe networks that carry domestic, industrial and storm water that are generated within an area of consideration and flows into treatment plants or water bodies. In olden days, the pipe networks were designed to take the combined flow of wastewater and stormwater. However, during extreme events like high intensity rainfall, the pressure on the system is found to be elevated.

Therefore, in the new areas, separate systems, where stormwater and wastewater flow in different pipes are being built and slowly combined systems are getting migrated towards separate systems.

We model and run simulations on these networks to check if the systems can be separated and also check for area constraints, capacity requirements and effects of the change in downstream areas.

Flood depth and extent of stormwater in/around a building

With ever growing cities and towns, new developments add pressure on the existing network. So we study the effects of every such developments (major or minor) on the system and if those are found to be detrimental then we look for alternatives to connect the development.

Integrated modelling involves building of the pipe network and rivers/channels in the model. We can study the effect of the pipe network discharge on the river/channel. It also helps us in determining the change in water level in the river, the course of water flow in case of flooding, and the vulnerable areas during storm events.

Before video: This is a stormwater modelling video of a simulation, before applying the solution – all the water is flowing into the houses. 

After: This is after the solution, where the ponds, swales are capturing the water thus reducing the overflow in the developed areas. 


Coastal engineering and modelling are primarily concerned with the specific demands posed by constructing at or near the coast like ports, harbors, marine outfalls etc., as well as the development of the coast itself. The understanding of waves, tides, sediment transport, storm surges, tsunamis and its impact on the coast/nearshore is essential for a coastal engineer/modeller to plan for the construction of man-made structures like ports as well as to deal with morphological changes of coastal topography. The areas of interest in coastal engineering include the coasts of the oceans, seas, marginal seas, estuaries and big lakes.

In the analysis of the coastal hydrodynamic processes, numerical and physical modelling are often employed to simulate the main phenomena in the coastal region and the results are used as acceptable justification to major decisions: location of ports, creation of man-made islands, sewage/thermal plant/de-salination plant discharges and ecological reserves.

Tsunami Model


Computational fluid dynamics (CFD) is a branch of fluid mechanics that uses numerical analysis and data structures to solve and analyze problems that involve fluid flows (gases or liquids). In the built environment we often need to understand air movement and its effects on temperature distributions and dispersion/mixing of gasses, smoke and other pollutants. CFD analysis therefore involves the understanding of interaction of liquids and/or gases with the surfaces using computer simulations. Some of the applications of CFD involves HVAC (Heating Ventilation & Air conditioning) analysis in metro stations and buildings , external aerodynamics around sky raisers , fire simulation of offshore/onshore & process facilities and in tunnels.

CFD analysis inside a building

Modelling also serves as a basis for designing as it validates the design done by designers. It also helps in selecting the most feasible and workable option that can be used for further stages of designing.

We have worked on a lot of magnificent projects for different countries such as Drain London, UK, Regional Coastal Water Quality Modelling – Dwr Cymru Welsh Water (DCWW), UK, Al- Khor, Qatar, E40-E314, Belgium.

Modelling is a niche field. It feels incredible to work on something that few people do around the world and be a part of sustainable growth.  Our projects not only help us gain technical understanding in modelling and designing but also gives us satisfaction of helping people and making their living environment better.

GEC has expertise in wastewater, river, stormwater, coastal and CFD modelling.  For more information please get in touch with