April 2010, Vol. 22, No.4


Quality Assurance for Models

There was an interesting discussion in “Hydraulic Forces” (January) regarding the use and practice of hydraulic modeling. The article was about a force main model that appeared to have errors, but most of them turned out to be “creative license” used by the modeler since the basic model wasn’t designed for the situation being modeled.

While I applaud the ingenuity of the modeler to adapt the model to the situation, there are two major problems with the approach described in the article. First, the design engineer/modeler should have documented every adaptation he had made to the model to make it work, and that documentation should have been a part of the facility record. Basically, the situation described is a breakdown in quality assurance. Second, when the modeler knew the model would not work as written, he should have initiated a task to update/revise the model to accurately reflect actual conditions. That is just good science and engineering.

Both of these lessons could have been stated more strongly in the article.


Christopher M. Timm
Vice president/Senior Project Manager
PECOS Management Services Inc.

Albuquerque, N.M. 


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