Open-Source Modeling Framework

Flow and Transport in Karst Systems

openKARST simulates flow and transport in complex karst conduit networks using the full Saint Venant equations. It handles mixed free-surface and pressurized flow, complex conduit geometries, transient and steady-state behavior, and friction laws including Darcy–Weisbach (using the Churchill friction factor correlation) and Manning. Ongoing development extends the framework toward coupling with porous media and catchment-scale hydrological processes.

News

Model Capabilities

openKARST provides a flexible framework for simulating flow and transport in complex karst conduit networks. While currently focused on conduit-dominated systems, the model is actively being extended toward broader hydrogeological applications, including recharge-driven forcing and more complex conduit–matrix exchange processes.

Hydrodynamic Flow Solver & Simulation

Fully transient and steady-state Saint Venant solver for free-surface and pressurized flow, optimized with vectorized NumPy operations. Support for diverse boundary conditions (water depth, flux, constant or time-series forcing).

Solute Transport & Particle Tracking

Supports advection–dispersion modeling and particle-tracking for analyzing transport under steady-state and transient conditions.

Flexible Conduit & Network Geometry

Handles real or synthetic diameter profiles, roughness distributions, and large conduit networks, including imports from external databases.

Friction & Hydraulic Formulations

Supports two friction modes: a full Churchill formulation (Darcy-Weisbach for both free-surface and pressurized flow) and a hybrid approach using Manning for free-surface and Churchill for pressurized conditions.

Visualization, Dashboards & Data Export

Interactive browser-based analysis with Plotly/Dash, including customizable observation points, and VTK export for advanced 3D visualization, rendering, and post-processing in ParaView.

Hydrogeological Coupling (In Development)

Active development toward hydrological coupling, reservoir-based phreatic exchange, and future integration with porous-matrix models.

Example Simulations

openKARST supports a variety of flow and transport scenarios, including transient pulse injections, solute transport, and simulations using real or synthetic conduit geometries. The examples below illustrate typical applications.

Transient Flow in Large 3D Karst Networks

openKARST supports stationary and transient simulations in large karst conduit networks, resolving flow propagation, network-scale connectivity, pressurization dynamics, and delayed system responses across highly interconnected geometries.

Free-Surface and Pressurized Flow

openKARST resolves transitions between free-surface and pressurized flow using the full Saint Venant equations. This allows simulation of wetting and drying fronts, rapid inflow events, and pressurization in partially flooded conduits, supporting realistic modeling of transient karst responses.

Advection-Dispersion Transport

openKARST includes an implementation of the 1D advection–dispersion equation for solute transport in conduit networks. This enables simulation of breakthrough behavior, dispersion effects, and early/late tailing phenomena in complex network structures.

Particle Tracking & Transport Pathways

openKARST provides particle-tracking capabilities for analyzing flow paths, travel-time distributions, and preferential transport in complex conduit networks. This enables assessment of connectivity, flow partitioning, and system-scale transport behavior.

About the Project

openKARST is an open-source framework for simulating flow and transport in karst conduit networks. The model is developed within the European Research Council project KARST: Predicting flow and transport in complex karst systems, which aims to advance our ability to model extreme events, network-scale processes, and multi-scale hydrodynamic behavior in karst aquifers.

The KARST project addresses fundamental challenges in understanding flow and transport in complex subsurface environments, including conduit-scale dynamics, catchment-scale network structures, and the development of new upscaled modeling approaches. More information is available on the ERC KARST project website.

Publications

Kordilla, J., Dentz, M., Hidalgo, J. (2025)
openKARST: A novel open-source flow simulator for karst systems
Computers & Geosciences, 106066
https://doi.org/10.1016/j.cageo.2025.106066

Get Started with openKARST

Whether you’re new to karst modeling or integrating openKARST into research workflows, the documentation and GitHub repository provide everything you need to begin. For feedback, questions, or potential collaborations, you can always reach out.