"Water Balance Model" incorporates Stream Erosion Module



Protect Watershed Health

The Water Balance Model is a scenario comparison tool. Launched in 2003, it can help local governments create a future watershed vision by informing their decisions about the impacts, or not, of their ‘water footprint’ on watershed health. In December 2011, the Water Balance Model Partnership completed a year-long program to rebuild both the website front-end and the user interface that connects to the QUALHYMO calculation engine.

“The scope of work included extending the QUALHYMO engine and Water Balance Model interface so as to enable  assessment of natural stream sections and development of an erosion index for watershed scenario comparison and development of mitigation methodologies,” announced Ted van der Gulik, Partnership Chair.


More Flow Volume = More Stream Erosion

“Erosion is a key factor in water resources management.  A principal result of increased volumes and rates of flow associated with urbanization is the consequent increase in stream erosion,” states states Jim Dumont, the Partnership’s Engineering Applications Authority.

“This can be an economically important factor as maintenance and hydraulic capacity is affected, and it can also be an ecologically important Jim dumont (120 pixels)factor as habitat is impaired through degradation, aggregation and increased suspended solids transport.” 

“Managing this effect has become a clear requirement that can be addressed through use of the Water Balance Model to assess and to establish mitigation techniques within the watershed.” 


Simulation of Irregular Channel  Shapes

“To enable this, what is needed is the ability to simulate and assess irregular natural channels along with the potential for erosion and the change in that potential resulting from alteration of the watershed through urban development,” continues Dr. Charles Rowney, the Partnership’s Scientific Authority.

“The QUALHYMO engine has some basic capabilities to assess a uniform trapezoidal section, so extending the model to enable irregular channel Dr. charles rowney (120pixels)simulation is a direct extension of what is already within the tool.  This is not a trivial extension, because the requirement is much more complex than what is already in the model, but the existing capabilities are proven and the path forward is clear.” 

“The basic relations that need to be considered are shear force, Stream Power, and Stream Impulse.”