Watercourses may be defined by line-elements in multiple layers. In combination with the TOPSYSTEM triwaco can simulate virtually any water system. On a regional scale from a delta to karstic terrain and on a local scale from complex drainage systems to entire artificial recharge & recovery schemes.

As part of this it is sometimes useful or even necessary to calculate changes in the surface water system together with changes in groundwater flow.

triwaco for that purpose offers the possibility to do so with either the SF-module or the module TRIFLOW. The SF-module can be used for calculations whereby infiltration from lakes or hollows in the dunes and superficial discharge is considered. TRIFLOW is able to calculate flow rate and surface water levels simultaneously. more >>

triwaco can also be coupled with a surface water model. For on-line coupling of the groundwater model triwaco with a surface water model Royal Haskoning has developed a coupling with DUFLOW and SOBEK (coupling with SOBEK developed toegether with WL | Delft Hydraulics). Currently we are developing an all-purpose coupling module.

Coupling with the surface water model

The coupling with a surface water model (DUFLOW, SOBEK or any other model) is carried out by a specifically designed module. This module runs the seperate models (for instance the groundwater model and surface water model).

Through an iterative process surface water levels calculated by the surface water model are exchanged with the groundwater model after which the groundwater model calulates fluxes which in turn are used by surface water model as boundary conditions. Not only is accounted for fluxes in main watercourses but also secundary watercourses and the drainage/infiltration system (TOPSYSTEEM, SOBEK-RR, DUFLOW-RAM).

Advantages

The coupling module is all-purpose. Watercourses are defined as line-elements and are given a unique user specified ID. This concept allows for easy linkage with other models. This link is defined conceptually and will work for any numerical discretization. So coupling with FLAIRS, MODFLOW, DUFLOW, SOBEK en SIMGRO in any combination is relatively simple to realise.

The modular structure of triwaco has the advantage that the models for groundwater, unstaturated zone and surface water can be created independently from each other. So the models can also be run as seperate models.

In other words triwaco offers the best of both worlds. Both an integrated hydrological modelling environment as well as the possibility to run the seperate models independently.