t 0.02 sinitial state
2D inundation,
solved on the GPU.
Deceris Inundation is an open-source 2D shallow-water solver for polygonal meshes, implemented with Vulkan.
Model flood depth, momentum and propagation through time — then inspect exactly how the result was produced.
01Hydrodynamics through time
Flooding is not an extent.
An inundation map tells you where water ended up. A hydraulic model describes how it got there.
Deceris Inundation evolves water depth and momentum over terrain through time using the two-dimensional shallow-water equations.
t 0.49 swave release
t 0.96 sradial front
t 1.50 spropagated field
hwater depth
|u|velocity
tₐarrival time
Ωinundation extent
02How it works
A finite-volume solver on polygonal meshes.
Geometry is prepared in Python. The numerical state is advanced on the GPU through HLLC fluxes, SSP-RK2 integration and CFL-controlled timesteps.
computational fieldcell view · 12.5 m
geometryMesh the terrainstage 1 / 4
Mesh inputspolygonal cells · optional bed elevation
GPKGSHPGeoParquetParquetOBJ03 Architecture
Why Vulkan?
GPU compute is part of the solver architecture, not an optimisation added after the numerical model.
Deceris Inundation uses Vulkan through Kompute to keep the computational core separate from a vendor-specific compute API.
MoltenVK supports development and correctness work on macOS.
workflowPython API
dispatchKompute
computeVulkan
LinuxNVIDIA GPU
macOSMoltenVK
04Validation
Evidence before claims.
Numerical software should be judged against problems with known or independently published behaviour.
Deceris Inundation is tested against analytical solutions and published Environment Agency / Heriot-Watt 2D hydraulic benchmark cases.
6validation suites
solver output
Analytical dam-break
Can the scheme reproduce a known solution?
The one-dimensional wet-bed dam-break compares numerical depth directly with the closed-form Stoker solution.
L1 error 0.0077acceptance gate 0.05
solver output
EA Test 3 · longitudinal side view
Watch momentum carry the surge across the crest.
The profile exposes the mechanism hidden in plan view: a fast bore descends the 1:200 slope, nearly fills the first depression, crosses the obstruction through conserved momentum, and leaves a disconnected pond in the second basin.
Bed elevation and water-surface profile along the domain centreline.
point 2 rise 0.047 mstill-water control 0.000 m
solver output
EA Test 3 · momentum obstruction
Does momentum carry water over the crest?
The incoming wave nearly fills the first depression. Conserved momentum carries part of the flow across the obstruction and into the second basin.
point 2 rise 0.047 mcontrol point 0.000 m
solver output
EA Test 2 · floodplain depressions
Can wet and dry regions remain physically distinct?
Water fills a sequence of depressions over complex topography while published far-field gauges remain dry.
storage ratio 0.99916 published gauges
solver output
EA Test 4 · flood propagation
Does the flood front arrive at the right time?
Six gauges track the advancing front against an axisymmetric reference over an extended flat floodplain.
worst arrival error 6.3%6 gauge locations
$ just benchmark-obstruction --backend gpu_resident_batch[mesh] obstruction-dem2010-150x50.parquet
[solver] Vulkan · gpu_resident_batch
[run] t = 900.0 s · snapshots saved
[gate] point_2_rise = 0.047 m
[artifact] summary.json · gauges.csv · manifest.json
[result] PASS
05 Reproducibility
Results with receipts.
Benchmark outputs are not screenshots assembled for the website. The harness produces the underlying data, plots, artifacts and provenance used to publish each result.
- benchmark configuration
- raw output and gauge series
- artifact hashes and manifest
- reproduction command
06 Existing workflows
Bring your mesh.
Deceris Inundation operates on polygonal computational cells. The initial release is for researchers and engineers who want to experiment with, inspect and extend a GPU-based 2D hydraulic solver.
GeoPackage GIS Shapefile GIS GeoParquet GIS Parquet GIS OBJ MESH
mesh preprocessingedges · CSR adjacency · cache
simulationdepth · momentum · time
07 Open source
The solver should be inspectable.
The numerical implementation, GPU shaders, benchmark harnesses and workflow API are being released under a permissive open-source licence.
Read the equations in code. Change them. Run the benchmarks again.
Open the source Licence · Apache-2.0flux.pysolver.pyworkflow.py
42float cL = sqrt(pc.g * max(hL, 0.0));
43float cR = sqrt(pc.g * max(hR, 0.0));
44
45float SL = min(unL - cL, u_roe - c_roe);
46float SR = max(unR + cR, u_roe + c_roe);
47
48if (SL >= 0.0) F = FL;
49else if (SM >= 0.0) F = FsL;
50else if (SR >= 0.0) F = FsR;
51else F = FR;
The solver answers
Where does the water go?
Deceris asks
What does that mean?
decerisInundationdepth · velocity · timing
buildingsinfrastructurepopulation
impact modelConsequencesexposure · disruption · loss
compareWhat-if scenariosevents · interventions · assumptions
follow the wateroutput → exposure → consequence → comparison
Deceris is a platform for exploring scenarios instead of stopping at a single model run. Change the event, intervention or assumption; then compare how the consequences move.
Try Deceris