Tom Walski, Ph.D., P.E.

Thomas Walski is a senior product manager at Bentley Systems, Inc. He has 40 years of experience in applied hydraulics. He is author of hundreds of journal papers and conference presentations and is the author or co-author of several books. He has won numerous awards for his work such as the best distribution and plant operation paper in the Journal AWWA on three occasions. In addition to developing software, he has served as a distribution system operations manager, engineering manager for a large water company, executive director at a regional sewer system and a university professor.

Law of Conservation of Ca (Rational Method version)

May 10, 2021

We all know that as two flows meet, according to the Law of Conservation of Mass, the resulting flow will be the sum of the two flows.

The Law of Conservation of Fixture Units

April 29, 2021

Last week my blog had what I’ll call the pseudo-Law of Conservation of Turbidity. 

Law of Conservation of Turbidity

April 27, 2021

We’re all familiar with the application of laws of conservation of mass and energy in models of water distribution systems. But did you know that..

Connecting Upstream/Downstream Systems: The Right Way vs. Ways Different People Do It

April 19, 2021

In a pipe network, all elements are connected such that changing anything at any location impacts the entire network.

Fun with the Navier-Stokes Equations

April 14, 2021

If you try to solve for the velocity at any point in a three-dimensional, Newtonian fluid, the correct equations you must solve are the..

Garbage In – Garbage Out

April 2, 2021

Recently, we’ve had some discussion on our Bentley’s Hydraulics and Hydrology communities forum on fixing a model where the piping at..


March 31, 2021

When I would walk into an engineering office (before the pandemic), I would be concerned by the lack of books on the shelves. I’m told that..

Part 2: Beyond Hydraulics – Real World Water and Sewer System Design

March 24, 2021

Welcome back for the second part of our “Real World Design” in hydraulics and hydrology! In the first part, we covered types of system design and..

Part 1: Beyond Hydraulics – Real World Water and Sewer System Design

March 18, 2021

Engineering schools teach the fundamentals of water distribution system design. Bentley’s training supplements that with training on the modeling..

Wave Speed for Transient Analysis

March 8, 2021

One of the most important inputs to transient analysis is the speed of the pressure wave (called celerity) moving through the pipes. The speed..