Water Balance Model website also hosts the "official" QUALHYMO hydrologic simulation model


logo - wbm powered by qualhymo (360p)


Commitment by Inter-Provincial Partnership will preserve legacy of tool developed by Dr. Charles Rowney

The British Columbia Inter-Governmental Partnership (BCIGP) and Dr. Charles Rowney have announced that the “official” QUALHYMO hydrologic engine will reside on the Water Balance Model for Canada website.

“Having both tools accessible from the same website provides drainage modellers with a choice, depending on the modelling objectives and the capabilities of the user,” stated Ted van der Gulik, BCIGP Chair. “There is an existing QUALHYMO community that comprises long-term and advanced users, and we see this is a way to introduce them to the potential of the Water Balance Model powered by QUALHYMO.”

The BCIGP is collaborating with the Alberta Low Impact Development Partnership and the Toronto and Region Conservation Authority to create an Inter-Provincial Partnership that will promote Canada-wide use of ‘green’ development practices.The three share a vision regarding the timeliness and appropriateness of QUALHYMO as the pan-Canadian hydrologic engine.


Stand-alone QUALHYMO

The QUALHYMO (QUALity HYdrologic MOdel) continuous hydrologic simulation model was developed in the early 1980s by Dr. Rowney for the Ontario Ministry of Environment, and is the tool of choice by experts in Ontario and Alberta. Then simulation methodology includes rainfall/runoff and snowmelt processes.

QUALHYMO can simulate surface hydrology as well as pollutant loads associated with surface runoff, and can route flows and pollutant loads through stream channels and rainwater/stormwater management facilities such as detention ponds. Pollutant removal processes that occur along channels or within ponds can be explicitly simulated.

Charles rowney (160p)“The stand-alone QUALHYMO and the Water Balance Model powered by QUALHYMO serve different needs,” explained Dr. Rowney. “A key message is that the stand-alone QUALHYMO has a comprehensive suite of analytical capabilities, of which the Water Balance Model currently uses only a portion. For this reason, we use the term ‘exposed features’ to describe the set of capabilities that are called upon by a user of the Water Balance Model interface.”

“Over time, we envision that we will expose more QUALHYMO features in order to provide the power users with enhanced capabilities when they apply the Water Balance Model,” added Ted van der Gulik. “Our immediate priority in promoting use of the Water Balance Model, however, is to provide a bridge between engineering and planning, and ultimately influence the greening of the built environment.” 


Greening the Built Environment

“The desired outcome in creating the Water Balance Model powered by QUALHYMO is that it will be a place to get dependable answers, a place where efficient and secure access to data, tools and methods is consolidated on an agreed common platform,” elaborated Dr. Charles Rowney. 

“Rather than expending effort re-inventing calculation methods and chasing routine data, stakeholders will focus on developing the results they seek in an accessible, flexible and proven environment that has been delivered with the features they have specified.  This tool is the professional computational and communication backbone that will take us towards the sustainable reality of a greening of the built environment.”



Kim stephens (120p)According to Kim Stephens, BCIGP Project Coordinator, “Over the 20 years or so following the initial release of QUALHYMO, no substantive control or development was attempted by Charles Rowney, because of his concern that such activity could conflict with the interests of the firms he was affiliated with. It is now possible for him to respond to requests for the further evolution of the software without any encumbrances, and this is great timing from a WBM perspective.”

“As well as next steps related to technical and support considerations, one thing we’ve discussed with Charles is responding to what we might call the legacy of the unmanaged circulation of QUALHYMO that has occurred over the years,” explained Stephens. “There are now versions of QUALHYMO floating about that may or may not be the ‘real thing’.” 


‘The Real Thing’

Stephens elaborated on this aspect as follows: “Over the last decade, there was one related model that Charles felt was a credible and managed effort (the QHM model circulated by the Technical University of Nova Scotia) but that is a proprietary model with a life of its own, and it is not known that all other QUALHYMO versions were as carefully handled as that one.”

“Even if they were, a multiplicity of QUALHYMO versions could cause confusion as we move forward in a managed process such as we’re committed to with the WBM,” continued Stephens. “So we needed a way to provide a confirmation to users that they were downloading a genuine copy of the model without tying it down with dongles or other paraphernalia commonly used in proprietary products.

According to Stephens, “To address the need for users to have access to genuine versions of QUALHYMO, Charles Rowney has taken steps to ensure that releases of the model are distributed by credible agencies committed to ensuring that the current version, and only the current version, is available.  The first of these agencies is the Water Balance Model.” 


What it means to be the “official home”

“By designating the Water Balance Model as the home of the official QUALHYMO, and with Charles committing to uploading new distributions to this home as they are produced, the Inter-Provincial Partnership believes this will both ensure the long-term integrity of the model and preserve Dr. Rowney’s legacy,” concluded Kim Stephens.

In Charles’ words, “During that 20-year period, the code was available to developers and users, and it seems that a number of alternative versions of QUALHYMO have appeared as a result. A casual survey suggests that these versions vary in their approaches to coding and simulation.”

“Discussions with individuals in the field suggest that the multiplicity of versions has led to a multiplicity of issues,” continues Dr. Rowney. “Moving to a formal distribution model lets us avoid confusion over which version is which, without making users cope with hardware or software locks.  In return, we’re counting on users to abide by the license agreement, which means that they’ll download what they need but not circulate it further.  I think this will work to the benefit of all users, without adding a lot of cost or needless restrictions to the model.”


Posted August 2008