01 / REGIONALCatchment-scale insight
Regional assessment
Fast answers for catchment-scale questions.
- Water balances
- Runoff and recharge
- Water availability
- Scenario testing
Water doesn’t work in silos. Neither should your models.
HydroOne
One catchment. One connected system.
Integrated water modelling from land surface to groundwater.
Hydro One connects surface water, soil water, groundwater and water demand in a single modelling framework.
△ Choose your level of detail△ Built to connect△ Modelling that scales with you
One hydrological system
Integrated water modelling
from land surface
to groundwater.
Hydro One connects surface water, soil water, groundwater, and water demand in a single modelling framework.
Choose your level of detail
Model at the scale you need.
Scale your modelling from rapid regional assessments through to fully coupled physical simulation.
02 / DETAILEDProcess-level understanding
Detailed simulation
Physics-based modelling for complex investigations.
- Flooding and overland flow
- Groundwater systems
- Infiltration and recharge
- Surface water interactions
From surface water, through the unsaturated zone, to the aquifer.
Explore the six modules by water-system component or modelling question.
6 modules
01 / SURFACE WATER
Rainfall, runoff and flooding
Flooding + overland flow02
FloodWarp
Simulate overland and floodplain flow with a two-dimensional, first-order finite-volume solver of the full shallow-water equations.
Where will floodwater go, and how deep will it get?
Methods + outputs
MethodFull two-dimensional shallow-water equations solved using a first-order finite-volume method (FV1). A local-inertial formulation is available as a reduced-complexity alternative.
OutputsInundation extent, water depths, flow pathways and hydrograph timing.
Catchment water balances01
Regional Runoff + Recharge
Assess catchment water balances with fast kinematic routing for runoff, run-on and recharge.
How does water move through a catchment, and what becomes recharge?
Methods + outputs
MethodKinematic-wave surface routing combined with soil-water balance accounting for catchment-scale runoff and recharge assessment.
Use forWater balances, runoff and recharge, water availability and scenario testing.
02 / SOIL WATER
Moisture, infiltration, recharge and crop use
Soil moisture + recharge03
Rushton
Track daily root-zone water storage, evapotranspiration, runoff and groundwater recharge.
How much water stays in the soil or becomes recharge?
Methods + outputs
MethodConservative Rushton-style daily water balance with soil moisture deficit, evapotranspiration stress and near-surface retention. Scalar and gridded engines include NumPy reference and Warp GPU implementations.
OutputsSoil moisture deficit, evapotranspiration, runoff and recharge.
Agricultural water04
Irrigation Demand
Connect crop-water demand and irrigation scheduling with delivery capacity, efficiency and abstraction accounting.
When is irrigation needed, and how much water is required?
Methods + outputs
MethodReference evapotranspiration and crop coefficients, depletion-based scheduling and coupled soil storage. Includes an accelerated fused GPU implementation.
OutputsCrop demand, irrigation applications, soil-water depletion and abstraction requirements.
03 / GROUNDWATER + SUBSURFACE
Aquifers, groundwater exchange and variably saturated flow
Variably saturated flow05
RichardsWarp
Simulate unsaturated and saturated flow through porous media, including infiltration, drainage and wetting fronts.
How does water move through the unsaturated zone?
Methods + outputs
MethodPressure-head Richards equation with van Genuchten–Mualem hydraulic properties. One- and three-dimensional research solvers with implicit CPU/GPU execution.
InvestigateInfiltration, drainage, wetting fronts, soil hydraulic heterogeneity and recharge processes.
Groundwater dynamics06
DarcyWarp
Model groundwater flow in two and three dimensions, including hydraulic heads, transient storage and head-dependent exchanges.
How will aquifer heads, storage and exchanges respond?
Methods + outputs
MethodSaturated and unconfined groundwater flow with CPU/GPU iterative solvers. The 3D implementation includes Cartesian and terrain-following grids.
OutputsGroundwater heads, aquifer storage, boundary exchanges and scenario response.
AvailabilityThe main branch provides 2D modelling. The 3D implementation is available on the dev branch.
View on GitHub
Explore 3D on dev Read the paper
Durney & Fourie (2026)
Environmental Modelling & Software, 204, 107081.Open access
Applied examples + numerical evidence
Real places. Inspectable modelling.
Explore a flood demonstration, a regional groundwater application and a field-data drainage comparison. Each example illustrates a different modelling capability.
Orton Bradley / regional landscapeFloodWarpReal-terrain demonstration
Orton Bradley Park
Banks Peninsula · Canterbury
A 72-hour rainfall-driven flood simulation on a 5 m grid, with maximum-depth maps and direct numerical comparisons against LISFLOOD-FP FV1.
- Grid resolution
- 5 m
- Duration
- 72 h
- Active area
- 14 km²
Research demonstration. Design-storm simulation and inter-model comparison, not a calibrated observed flood event or an official hazard assessment.
DarcyWarpRegional application
Canterbury regional groundwater modelling
Environment Canterbury · New Zealand
A 45,000 km² steady-state groundwater model developed using DarcyWarp for Environment Canterbury. The model formed the basis for 1,435 accepted, calibration-constrained NSMC realisations.
- Modelled area
- 45,000 km²
- Model type
- Steady state
- NSMC realisations
- 1,435 accepted
RushtonField-data comparison
Ashley Dene — soil drainage
Canterbury · New Zealand
Rushton simulations compared with drainage measured in three ryegrass–clover pasture lysimeters at Ashley Dene. The comparison uses measured rainfall, a +10% rainfall sensitivity and ERA5-derived Penman–Monteith potential evapotranspiration, with two predefined soil-parameter cases. No calibration to drainage observations was undertaken.
- Observed drainage
- 3 lysimeters
- Parameter cases
- 300 / 600 mm
- Calibration
- None
Comparison scope. Reported NSE values describe monthly drainage over complete matched months; cumulative curves show the accumulated totals. Lysimeter drainage is not necessarily groundwater-table recharge.
Numerical verification
DarcyWarp: a reproducible analytical check
A small synthetic confined aquifer with uniform recharge, fixed heads and no-flow sides. The numerical head profile is checked against an analytical solution, separate from the Canterbury model.
Built to connect
Follow the water.
Connect the processes.
Surface water, soil water, groundwater and water demand are parts of the same hydrological system. Hydro One brings these perspectives together around your modelling question.
- 01
From rainfall to runoff
Understand catchment response, overland flow and flooding.
- 02
Through soils and water use
Represent soil moisture, infiltration, recharge and irrigation demand.
- 03
Into groundwater and back to streams
Investigate aquifer storage, groundwater flow and surface water interactions.
One connected system
One connected water system. A conceptual view of the processes represented across the toolkit; not a simulation output or a map of implemented software links.
A framework for your modelling question
Start with the question.
Choose the right detail.
Bring the processes, methods and computational effort into line with the investigation.
01 / DETAIL
Choose your level of detail
Use rapid water balances and regional routing for broad questions, or detailed surface and subsurface physics where the processes need closer investigation.
02 / CONNECTION
Built to connect
Bring surface water, soil water, groundwater and water demand into a shared modelling framework, with explicit attention to transfers and water balances.
03 / SCALE
Modelling that scales with you
Start with an individual module or regional assessment, then add processes and detail as the question develops.
Working research software
The individual modules are implemented. Coupled workflows, shared interfaces and wider validation continue to develop; the appropriate configuration depends on the application.
Research · Applications · Collaboration
Got a modelling challenge?
Let’s talk.
Talk to Patrick Durney about your catchment, application or research question.