When developing regional groundwater models, it is often necessary to represent complex river systems which may exist over a drainage basin. In order to simplify the representation of such river systems in a 3D regional groundwater model, SoilVision Systems Ltd. has implemented a special Rivers object which can be used to represent complex river systems on the top surface of a numerical model. The implementation of the Rivers object is another aspect which makes SVFlux™ the ideal groundwater model choice for regional groundwater flow.
The Rivers object manager is implemented off of the Model > Boundaries > River Manager menu. Single or multiple river systems can be represented without the need to calculate the Z-coordinate over complex topography. Each river object can be represented as a single or multi-line segment object. The implementation also allows mesh spacing to be sent along the object. The river object is assumed to have a head boundary condition equal to the elevation of the topography at the particular (X, Y) coordinate. The mesh generation responds to the applied River objects such that node points are placed along the extents of each river object.
The value of such a Rivers object is apparent in the modeling of the Waterloo regional model. In this model, there are a number of rivers which cross the model domain at various points. The Rivers object allows easy input of such complex river systems. Their resulting influence on the flow regime can then be calculated after running the numerical model. If there are high gradients next to the Rivers object then the automatic mesh refinement will respond to these situations and refine the mesh accordingly. The figures below show the initial model set up for the Waterloo numerical model. The location of the rivers in the model can be seen. The use of the River object is therefore a productivity tool that allows faster creation of more complex regional groundwater models.