Simulation Engine

"Comprehensive model management and results interpretation tools for water engineers"


InfoWorks RS uses an enhanced version of the ISIS engine, world renowned for it's speed and unparalleled control over the simulation. We detail below the reasons why it is the industry-leading solution.

Stable across the widest range of flow conditions

The simulation model is based around the solution of the St Venant equations for open-channel flow using the Preissman 4-point "box" scheme. This can be demonstrated to be stable across a wider range of flow conditions than other generally available solution techniques.

The engine is able to calculate rainfall-runoff hydrographs, carry out flow routing and generate either steady-state (backwater) or full hydrodynamic solutions within a single simulation. Both the steady and unsteady flow solvers are able to solve for super-critical flow conditions.

Handles all network and river structures

Looped and dendritic networks are accommodated, as well as complex floodplains where areas may be defended by embankments or levees. Structures can be incorporated using standard methods, eliminating the need for the user to pre-calculate structure performance curves. Structure operation can be either time-based, or can be operated in logical mode where the user pre-defines a set of logical rules for the structure behaviour.

In Summary

Key features and benefits of the RS hydraulic engine include:
  • Incorporates rainfall-runoff, flow routing, steady-state and full hydrodynamic methods within a single simulation environment.


  • Solves the St Venant equations using the Preissman 4-point scheme. This method of solution can be shown to be stable across a wide range of flow conditions.


  • Unparalleled support for modeling structures including weirs, sluices, bridges pumps and culverts, without the need for pre-calculation of flow-level tables. Complex structure operation policies are included using a unique system of control based on logical rules.


  • Accommodates simulation of flows with high Froude numbers, both in the steady-state and unsteady flow solvers.


  • A range of modeling techniques allows highly complex floodplain to be modeled, including areas protected by embankments or levees.


  • Flexible model construction allows complex systems to be simulated, including dendritic, branching and highly looped systems.


  • The engine is continuously being improved and developed in line with the InfoWorks RS release programme
1989 RIBAMAN Catchment based rainfall-runoff & flow routing package for dendritic networks(DOS)
1989 MICROFLUCOMP Dynamic and steady state modeling package for river channels, structures and floodplains (DOS)
1992 SALMON-F Dynamic and steady state modeling package for river channels, structures and complex floodplains, including looped systems and embanked channel systems (DOS & UNIX)
1992 SALMON-Q Fully featured modeling package for simulating water quality processes in channel systems (DOS & UNIX)
1995 ISIS v1.0 Dynamic and steady state modeling of looped and dendritic river networks, including complex structures and floodplains, with integrated water quality and sediment transport processes which had a limit of 2,000 nodes.
2001 InfoWorks RS Consists of a single environment that integrates hydraulic modeling with comprehensive data management and links to GIS systems, which includes a new limit of 5,000 nodes. (Windows, NT)