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Service 03

Hydraulic Modelling
1D/2D flood simulation.

Advanced 1D and 2D hydraulic simulations predicting flood depth, velocity and flow paths — the technical backbone underpinning every credible flood risk study, dam safety assessment, and drainage design.

HEC-RASMIKE FloodInfoWorks ICM1D/2D coupledRiver systems10–21 days
At a glance
10–21 days
Standard delivery
1D/2D
Model capability
RP1000
Max return period
Every study includes
  • 1D river & channel modelling — steady and unsteady flow
  • 2D floodplain inundation across complex terrain
  • Bridge, culvert & hydraulic structure assessment
  • Model calibration against historical flood events
  • Named engineer · Post-delivery support
HEC-RAS
Primary modelling tool
1D–2D
Coupled capability
RP2–1000
Return periods
MIKE Flood
Complex sites
What it is

Hydraulic Modelling — what HYDRisk delivers.

Hydraulic modelling is the technical engine behind every flood risk assessment. It takes hydrological outputs — peak discharges, flood hydrographs — and converts them into spatial predictions of where water will go, how deep it will be, how fast it will flow, and how long the flooding will last.

HYDRisk hydraulic models are built from site-specific geometric data — not generic DEM datasets applied without verification. Every model is calibrated against available observed flood data, and validated against independent sources before results are accepted.

The choice of modelling approach — 1D steady-state, 1D unsteady, 2D dynamic, or coupled 1D-2D — is made on a project-by-project basis based on the hydraulic complexity of the site, the precision required, and the regulatory framework being satisfied. We do not apply a standard approach regardless of context.

Outputs are delivered as GIS-format flood hazard maps in GeoTIFF and Shapefile — directly usable in planning portals, design software and client GIS systems — alongside a structured technical report.

Why model selection matters
“The difference between 1D and 2D modelling is the difference between a result that satisfies a lender's technical advisor and one that raises questions.”
Model approach matched to site complexity
Calibrated — not generic DEM assumptions
GIS-ready GeoTIFF & Shapefile outputs
Model files delivered with every study
Why it matters

Four reasons this service is critical to your project.

Understanding what this study delivers — and what happens without it — is the fastest way to evaluate whether your project needs it.

1D/2D modelling is the only accurate way to predict flood extent
Flood maps produced without a calibrated hydraulic model are based on assumptions, not physics. Lender advisors and regulators increasingly reject reports lacking real modelling behind the flood extent.
Bridge and culvert failures are predictable — and preventable
Most infrastructure flood failures occur at hydraulic structures where capacity is exceeded. A model identifies these failure points before construction, at a fraction of the cost of post-failure repair.
Dam & embankment safety requires breach hydraulics
Any dam or flood storage structure must be assessed for overtopping and breach risk. Downstream hydraulic modelling is a regulatory requirement and essential input for emergency planning.
Uncalibrated models mislead design decisions
A model that has not been validated against observed flood behaviour can under- or over-state risk. Calibration is what turns a simulation into evidence a lender or regulator can rely on.
What we deliver

Specific deliverables — not vague promises.

Every HYDRisk study produces a defined set of technical outputs — here is exactly what you receive.

Technical analysis outputs
  • 1D river hydraulic model — steady-state and unsteady flow simulation
  • 2D floodplain inundation model across full extent of interest
  • Coupled 1D-2D model for river/floodplain interaction sites
  • Flood depth, velocity and hazard maps — all return periods
  • Bridge and culvert capacity assessment — pre/post design changes
  • Model sensitivity analysis and uncertainty quantification
GIS & report deliverables
  • Flood inundation maps — GeoTIFF & Shapefile per return period
  • Flood hazard maps — depth, velocity, composite classification
  • Hydraulic model report — geometry, calibration and results
  • Model files — HEC-RAS or MIKE Flood — for client/regulator review
  • AutoCAD DXF overlay for structural design team integration
  • Executive summary — suitable for non-technical stakeholders
Model files: All hydraulic model files (HEC-RAS, MIKE) delivered with results. Geometry, boundary conditions and calibration data included. GIS outputs in GeoTIFF and Shapefile.
Request a scope →
Tools & methodology

Industry-standard tools. Region-specific data.

Every tool we use is the same software trusted by government agencies, major engineering firms and regulatory bodies worldwide.

HEC-RAS
US Army Corps of Engineers
Global standard for 1D/2D hydraulic flood modelling — river systems, floodplain inundation, infrastructure hydraulic assessment.
Steady & unsteadyDam breach
MIKE Flood
DHI Group
Advanced coupled 1D-2D flood simulation for complex urban, coastal and estuarine environments requiring high resolution.
Urban floodingCoastal
InfoWorks ICM
Autodesk / Innovyze
Integrated catchment modelling for combined sewer and urban drainage hydraulic assessment.
Urban drainageSewer networks

Step-by-step methodology

Step 01
Data & geometry collection
Survey data, DEM processing, channel cross-sections, structure geometry, roughness coefficients, flood records.
Step 02
Model build & geometry
Geometry built from terrain data. River network delineated. Boundary conditions from hydrological outputs.
Step 03
Model calibration
Observed flood data used to calibrate roughness values and model parameters. Calibration report produced.
Step 04
Flood scenario simulation
Simulation for all required return periods (RP2–RP1000). Depth, velocity, duration and hazard outputs extracted.
Step 05
GIS map production
Inundation rasters processed in QGIS/ArcGIS. Hazard classification applied. Maps formatted for planning portals.
Step 06
Technical report
Hydraulic model report covering geometry, calibration, scenarios and results. Model files delivered.
Regional applicability

Calibrated for your region and regulatory framework.

Methodology, data sources and regulatory requirements differ between geographies. HYDRisk delivers the right approach for every region.

United States — Primary market
FEMA-aligned methodology
NOAA rainfall, USGS discharge, FEMA floodplain standards and state-level compliance.
Regulatory frameworks
FEMA NFIPUSACE
  • NOAA Atlas 14 rainfall for frequency analysis
  • USGS discharge data for calibration
  • FEMA FIRM map review & compliance reporting
Middle East & GCC
GCC-specific methodology
GSMaP rainfall, arid-region hydrology, wadi flash flood methods, GCC regulatory compliance.
Regulatory frameworks
UAE MunicipalityAshghal (Qatar)
  • GSMaP satellite rainfall for arid catchments
  • UAE, Saudi Arabia, Qatar, Oman, Kuwait coverage
  • Bankable studies for GCC lenders
International
IFC & global methodology
ERA5 reanalysis, CMIP6 projections, IFC Performance Standards, Equator Principles compliance.
Regulatory frameworks
IFC PS1 & PS4Equator Principles
  • IFC Performance Standards PS1 & PS4 compliance
  • Equator Principles E&S due diligence
  • Remote delivery — any geography covered
Related services

Services often commissioned alongside this study.

Service 01
Flood Risk Assessment
Every FRA relies on hydraulic modelling to produce the flood extent outputs regulators and lenders require.
View service →
Service 04
Hydrological Studies
Peak discharge outputs are the boundary conditions that feed directly into the hydraulic model.
View service →
Service 08
Dam Break & River Flood Modelling
Dam safety hydraulic modelling — breach simulation, flood wave propagation and downstream hazard mapping.
View service →

Ready to commission your hydraulic model?

Tell us your site, river system, and study purpose. We will recommend the right modelling approach and have a fixed-fee scope back within 24 hours.

Get a free consultation →
Proposal within 24hFixed-fee pricingNo obligation