Pluvial Flood Simulator
Pick a site, set a rainfall depth, and press Run. The Continuuiti Pluvial Flood Solver moves that rainfall across real terrain and shows where the water actually collects. Buildings are stamped into the ground, so water is pushed around them rather than through them. It is the same solver that runs on the Continuuiti platform, where you can point it at your own locations.
The pluvial flood simulator needs JavaScript and WebGL. Enable both, or open this page on a desktop browser.
How this flood simulation moves water across the ground
Most quick flood visuals shade everything below a chosen elevation. That answers a different question: what would be wet if water arrived from somewhere else. A flood simulation has to move the water instead. Rain falls on the grid, runs downhill across a real surface, and collects in the dips.
The terrain is subdivided to roughly ten metre cells and building footprints are stamped into it as obstacles. That distinction matters most in dense blocks, where the gap between two buildings decides whether water drains away or backs up against a wall. The depth matrix beside the plan view reports a value for every cell around the site, so you can read the numbers rather than judge a colour.
Drainage behaviour changes what the flood simulation returns
Each site loads on selection, so you only download the one you are looking at. Terrain quality, vertical error and the source licences are listed inside the tool once a site is chosen.
| Site | What it shows | Buildings |
|---|---|---|
| Meyerland, Houston | Low-relief suburban ground, flooded repeatedly since 2015. | 1,878 |
| Kampung Melayu, Jakarta | Dense kampung on the Ciliwung riverbank, where spacing between structures drives the result. | 5,303 |
| Mexicali, Baja California | Arid valley floor on an irrigation grid, where drainage is engineered rather than natural. | 1,653 |
| Bund Garden, Pune | Dense monsoon-season city block on a plateau. | 4,801 |
| Porto Belo, Santa Catarina | Coastal Brazilian town where the ground sits close to sea level. | 262 |
| Braço do Norte, Santa Catarina | Steep valley town where rainfall runs off fast and ponds in narrow pockets. | 381 |
Run a flood simulation at your property address
Generate the terrain for any address on Earth and run the same solver across the rainfall scenarios you choose.
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Every flood simulation starts with a terrain bundle
Before any water moves, the ground has to be assembled. Continuuiti’s site bundle service resolves a single coordinate into three aligned layers across a two kilometre box: a bare-earth elevation grid, building footprints, and road centrelines.
The solver then refines that grid to a working mesh of roughly ten metres and stamps the footprints in as obstacles. Water is routed around structures instead of passing through them, which is what makes the gaps between buildings matter. Each bundle also carries a per-cell vertical uncertainty band, so the terrain reports its own error rather than presenting a single elevation as exact.
What a flood model needs before you can act on it
Three things decide whether a flood model is worth acting on at a single address.
The data sources are named. Every layer is published, licensed and citable, and the tool names the exact stack for whichever site you have selected alongside the vertical error of its terrain. A tool that will not tell you which elevation model it used cannot be checked against anything.
The output is a depth for every cell. A ten metre grid of depths shows which side of a building fills first and how deep the water gets there. Summary risk scores compress all of that into a single figure for the whole location.
The depths come from a physics based solver. The model routes rainfall over the terrain and solves the movement of water, then reports inundation depth across the two kilometre box centred on the selected site, under the solver parameters set for that run.
Run this flood simulation on your own locations
The sites here are worked examples with the controls fixed at platform defaults. An account opens the rest of the model.
- Any coordinate on Earth. The bundle service fetches terrain, footprints and roads for the point you give it and returns depths on the same grid.
- Storm forcing over a duration. Apply a rainfall depth as an instant volume or spread it across a storm of a set length. Duration is what lets a depth be tied to a return period.
- Solver parameters. Manning’s n for surface roughness, CFL and q-centering controls on the numerical scheme, closed-wall or free-draining boundaries with an adjustable apron, mesh subdivision, and the default wall height used when a footprint carries no measured height.
- Export. Take the solved terrain and the depth field out as data for your own reporting.
Create a free account to run it on your own sites.
Where a pluvial flood simulation is used
A flood simulation produces a depth grid, and that output feeds several different decisions.
Site and property risk assessment. A depth grid at ten metres answers which part of a site floods and how deep, which a portfolio-level score cannot.
Transaction due diligence. Screening a portfolio before committing to full engineering assessments narrows the list to the sites that need one.
Loan portfolios and underwriting. Surface water exposure at a specific address is a separate question from whether that address sits in a river or coastal flood zone, and a property can fall outside both and still flood from rainfall. Running a book of addresses shows which collateral or which risks warrant a closer look before terms are set.
Physical risk screening for climate disclosure. IFRS S2, ESRS E1 under CSRD, AASB S2 and California SB 261 all require entities to identify physical climate risks and say which data sources and scenarios they used. ESRS E1-2 is explicit that screening must run across hazard types with documented sources. Surface water flooding is a hazard type that river and coastal datasets do not capture, and a run here produces named sources, a stated vertical error and a reproducible method.
Continuuiti supplies the underlying data and analysis. Interpretation, materiality judgements and the disclosure itself remain the reporting entity’s own.
Frequently asked questions
What can I do with the flood depth data?
A depth by itself tells you where water gathers. Paired with a depth-damage curve it becomes a loss estimate. Take the depth this simulation reports for the cell your building sits on and look it up in the free flood damage calculator, which applies FEMA HAZUS and JRC depth-damage functions across 33 building types and returns a damage ratio for structure and contents. Add a replacement value and that ratio becomes a monetary figure. Note the units: this simulation reports depth in metres and the calculator takes feet. Where the rainfall came from a return-period curve, the result is a loss estimate at that return period, which is what a value at risk figure is built from.
How do I decide what rainfall amount to use?
Use the rainfall frequency curve published for your location. An intensity-duration-frequency curve gives the rainfall depth expected for a given storm duration and return period, so a one hour storm at a one in one hundred year return period resolves to a specific number of millimetres. Those curves are local: a curve fitted ninety kilometres away can be wrong by half. Continuuiti supports customers in identifying and applying the right curve for a site. A depth only carries a return period when the storm has a stated duration.
What is a flood simulation?
A flood simulation takes a rainfall depth, applies it to a terrain surface, and computes where the water flows and collects. Unlike a static flood map, it solves the movement of water over time, so you can watch ponding build and see which low points fill first.
How is this different from a flood risk score?
A score compresses a whole location into one number. A flood simulation returns a depth for every cell on the grid, so you can see which part of a site floods, how deep, and which way the water moved to get there.
Does this run on my own address?
Yes. Sign up with Continuuiti to generate the terrain map for your address and run our solver across various rainfall scenarios to understand ponding and pluvial flood risk.
What is the difference between pluvial and fluvial flooding?
Pluvial flooding comes from rain arriving faster than the ground and drains can take it away. Fluvial flooding is a watercourse overtopping its banks. This simulator covers the first case only. For the difference in full, see fluvial and pluvial flood risk compared.
Book a live demo
We will run a flood simulation on a site you pick and walk through the depths, the damage curves and the export on the call.
Free location report, shown live on the call.
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