Practical Engineering

Engineers need to be able to predict how water will behave in order to design structures that manage or control it. And fluids don’t always behave the way you’d expect. On this episode of Practical Engineering, we’re talking about one of the most interesting phenomena in open-channel flow: the hydraulic jump.

A weir is a small dam built across a river to control the upstream water level. Weirs have been used for ages to control the flow of water in streams, rivers, and other water bodies. Unlike large dams which create reservoirs, the goal of building a weir across a river isn’t to create storage, but only to gain some control over the water level. Over time, the term weir has taken on a more general definition in engineering to apply to any hydraulic control structure that allows water to flow over its top, often called its crest. In fact, the spillways of many large dams use weirs as control structures. So how do they work?

Dams serve a wide variety of purposes from hydropower to flood control to storage of water for municipal and industrials uses. But when a dam’s useful purpose fades away, the structure itself still remains. Dams come in all shapes and sizes, but contrary to what you might think, the most dangerous dams are often the smallest, also known as low head dams.

A quick overview of how we build underwater structures.

Traffic management in dense urban areas is an extremely complex problem with a host of conflicting goals and challenges. One of the most fundamental of those challenges happens at an intersection, where multiple streams of traffic - including vehicles, bikes and pedestrians - need to safely, and with any luck, efficiently, cross each others’ paths. However we accommodate it now or in future, traffic will continue to be one of the biggest challenges in our urban areas and traffic signals will continue to be one of its solutions.

We normally build a dam to hold water back and store it for use in water supply, irrigation, hydropower, or flood control. But sometimes we have to let some water go. Whether we need it downstream or the impounded water behind the dam is simply too full to store any more, nearly every dam needs a spillway to safely discharge water. The spillway is a critical part of any dam and often the most complex component. So how does it work?

The modern world depends on electricity. It’s a crucial resource, especially in urban areas, but electricity can’t be created, stored, and provided at a later time. The instant it’s produced, it’s used no matter how far apart the producer is from the user. And the infrastructure that makes all this possible is one of humanity’s most important and fascinating engineering achievements: the power grid.

Continuing the series on the power grid by diving deeper into the engineering of large-scale electricity generation.

Untangling the various equipment you might see in an electrical substation.

Discussing some of the fascinating engineering that goes into overhead electric power transmission lines.

The vast majority of our grid-scale storage of electricity uses this clever method.

Exploring the protective systems that keep the power grid from self destructing.

A quick description and demo of this ingenious pump.