The problem was that the people who developed the data underlying the GIS/CAD (I’ll call it GIS in this blog) used to build the model were not careful in how they laid out intersections. They would run the same pipe down several blocks without consideration of whether crossing pipes were interconnected. While we have tools in our model to clean up these issues (View > Network Navigator), it is best to avoid them from the start. Read Tom Walski’s blog and learn how to fix a model where the piping at intersections was poorly represented.

The exact right-of-way for a pipe or land acquisition for a tank or pump station is not generally considered in explicitly in master planning but can have a significant effect on costs. Costs can vary dramatically and are not simply a function of diameter. Over a reasonable range of pipe sizes, the effects of laying condition far outweigh the effect of pipe size in determining cost.

This blog series attempts to present some important considerations in system design that are important but generally are overlooked in schools. Experienced engineers will be familiar with these issues, but inexperienced engineers run into them frequently until they learn.

One of the most important inputs to transient analysis is the speed of the pressure wave (called celerity) moving through the pipes. The speed depends on the fluid properties and pipe properties and has a significant impact on the magnitude of the transient pressure wave and the speed at which it moves through the pipes.

The current technology for converting a constant speed pump into a variable speed pump is a variable frequency drive (VFD). In certain situations, converting a pump into a variable speed pump can save a considerable amount of energy. However, in some cases, installing a VFD won’t even pay for the cost of the VFD, and in others, it’s possible to use even more energy by using variable speed pumping. How can that be?

Isolation valves are an essential part of water distribution systems. Without them, a single pipe break can shut down an entire system while repairs are performed.

The concepts of tractive force design for sewers have been around for a long time. (Actually, the term “tractive force” is incorrect as “tractive stress” does have units of force per unit area along the pipe wall in the direction of flow.)