Flood modelling services for flood risk assessment and floodplain mapping.

Flood study inputs

A useful flood model starts with the decision, geography and available evidence. We document data quality before translating results into recommendations.

• DEM preparation, terrain review and floodplain context
• Catchment delineation and drainage analysis paths
• Historical rainfall, IDF curves and design-storm assumptions
• River flow records, gauge context and boundary condition notes where available
• Land use, land cover, soil, imperviousness and runoff context
• Hydraulic structures, roads, culverts, outlets and local constraints

Hydrological and hydraulic modelling

Workflows can range from rapid flood susceptibility screening to deeper hydrological and hydraulic modelling support depending on the risk, budget, resolution and available data.

• Rainfall-runoff analysis and hydrograph preparation
• HEC-HMS-style hydrological workflows for catchment response
• 1D river modelling and 2D floodplain or surface-water modelling support
• Urban drainage, road-flow and overland-flow screening
• Flood extent, flood depth, velocity and affected-asset maps where inputs allow
• Calibration, sensitivity and uncertainty notes for review

Decision outputs

Outputs are built for review, not just presentation. Assumptions, scenarios, confidence and limits remain visible so teams can validate the next step.

• Flood risk assessment reports and planning notes
• GIS layers for floodplain mapping, inundation mapping and exposed assets
• Drainage constraint, flow path and outlet maps
• Site or portfolio-level flood screening for insurance, utilities, real estate and infrastructure
• Flood mitigation and flood management strategy notes
• Climate resilience context where future rainfall, river flood or surface-water risk matters
• Recommended field, drainage, survey or engineering validation

Flood modelling methods

The right flood risk mapping method depends on the decision, available terrain, drainage detail, rainfall evidence, design standard and whether the output is for screening, planning, insurance review or engineering validation.

• Conceptual model review: map the main flow routes, receptors, structures, survey needs and model boundaries before detailed hydraulic setup.
• Terrain and DEM conditioning: review sinks, bridges, embankments, flow paths, vertical units and drainage artefacts before modelling runoff or inundation.
• Catchment delineation: derive watersheds, outlets, flow direction, flow accumulation and drainage paths to understand where water concentrates.
• Rainfall and design storm analysis: use historical rainfall records, IDF curves, return periods and climate scenarios to define storm inputs.
• Rainfall-runoff modelling: estimate runoff response using catchment area, slope, land cover, soil, imperviousness and loss assumptions.
• Hydrograph preparation: prepare peak flow, timing and runoff volume inputs for review or downstream hydraulic modelling.
• 1D and 2D hydraulic modelling support: support channel geometry, floodplain mesh, inflow and downstream boundary conditions, roughness, water-surface review and sensitivity notes where detailed modelling is needed.
• Hydraulic model QA: review timestep choice, mass balance, mathematical stability, parameters, outputs and reporting assumptions where model files are available.
• Urban drainage and surface-water screening: evaluate overland flow, road ponding, low points, culverts and drainage constraints in built-up areas.
• Flood susceptibility screening: combine terrain, flow accumulation, water proximity, drainage constraints and land cover where rapid portfolio screening is more appropriate than a full model.
• Inundation and exposure mapping: overlay flood extents, depth classes, roads, structures, parcels, utilities or assets to show what may be affected.
• Scenario and uncertainty review: compare assumptions, data limits, return periods and model sensitivity so results are not treated as false precision.

Common flood modelling use cases

Flood risk assessment is useful whenever a location decision needs evidence before capital, underwriting, design or field time is committed.

• Floodplain mapping for site planning, land acquisition and layout decisions
• Flood exposure screening for property, collateral, insurance and portfolio review
• River, surface-water and urban drainage risk assessment for infrastructure corridors
• Utility, telecom, road and logistics asset resilience screening
• Climate flood risk and rainfall scenario review for long-term planning
• Flood mitigation option comparison before detailed engineering design