Tag: infrastructure

The Art of French Drains
Civil engineers face a constant challenge trying to protect their structures from water — both above and below the ground. Subsurface water can build up enough pressure to lift and damage structures, so engineers use subsurface infrastructure — like French drains — to control the water underground. Despite the name (and my title pun), French drains have nothing to do with France. Instead, they are named for Henry French, an author who described their construction and use in the 19th century. These drains use a combination of rocks, mechanical filters, and perforated pipeline to guide subsurface water and drain it away from foundations. (Video and image credit: Practical Engineering)
September 11, 2024
Engineering the City of Venice
In 452, Roman refugees established what became the city of Venice across a series of low-lying marshy islands in a lagoon. With no solid ground available, Venice has needed clever engineering for its infrastructure, as discussed in this Primal Space video. That started with building the first piles — which still survive to this day — by driving long timbers down into harder clay levels. Because these wooden poles sit entirely below the water and are capped with stone foundations, they are preserved against rotting.
As Venice grew over the next thousand years, its citizens had other infrastructure problems to solve. When fresh water needs outstripped what could be delivered by boat from the mainland, Venetians redesigned the substructure of each square to capture, filter, and store rainwater. And to wash away waste, they designed tunnels that use gravity and the daily tides to flush out sewage. (Video and image credit: Primal Space)
September 9, 2024
Fish Ladders Keep Species Swimming
Dams often use fish ladders to help migratory species make their way upstream without interruption. In this video, Grady from Practical Engineering discusses some of the considerations that go into this special infrastructure and what kinds of designs work for different species. The first challenge for any dam is attracting fish to the ladder, which is often done by regulating the water flow at the entrance to create the velocity and turbulence that fish look for when going upstream.
Once fish are in the ladder, they travel up a series of jumps that break the dam’s elevation into manageable steps. Different dams use various baffle designs to create jumps suited to their local species and the way they like to swim. Calmer spots in each section give fish a spot to rest before they carry on. In well-designed systems, the vast majority (97%!) of fish that enter a ladder make it through to the other side. (Video and image credit: Practical Engineering)
Fediverse Reactions
July 3, 2024
Helping Fish Bypass Hydro Power Dams
Many dams in the U.S. were built at a time when their ecological impact was not a major concern. But, thanks to ongoing efforts to study affected species and upgrade infrastructure, many dams now balance human energy needs with the needs of non-humans, like migratory fish populations. In this video, Grady from Practical Engineering takes us behind-the-scenes at McNary Dam in the Pacific Northwest, where special plans and equipment help adult fish swim upstream and juvenile fish pass downstream with as little impact as possible. It’s impressive just how widespread and thorough their infrastructure for letting fish and lampreys through is! There are even facilities to help naturalists track and study the populations passing through. (Video and image credit: Practical Engineering)
June 17, 2024
How Spillway Gates Work
Dams and reservoirs need a way to control their water level, and for many, that’s managed using spillway gates. In this video, Grady from Practical Engineering introduces several types of spillway gates, including their advantages and disadvantages. As always, he’s got neat tabletop demonstrations of each type, and he digs into the practical issues engineers face when building, maintaining, and repairing these critical pieces of infrastructure. (Image and video credit: Practical Engineering)
February 8, 2023
When Reservoirs Run Dry
With the ongoing megadrought in the U.S. Southwest, more and more reservoirs are reaching historic low water levels. So it’s worth asking: what happens when a reservoir runs dry? And what, exactly, does a reservoir do in the first place? In this Practical Engineering video, Grady tackles both questions and takes a look at the many disciplines — beyond just civil engineering — that go into making a functional reservoir. (Image and video credit: Practical Engineering)
August 15, 2022
How Canal Locks Work
For thousands of years, boats have been a critical component of trade, efficiently enabling transport of goods over large distances. But water’s self-leveling creates challenges when moving up and downstream through rivers and canals. To get around this, engineers use locks, which act as a sort of gravity-driven elevator to lift and lower boats to the appropriate water level. In this video from Practical Engineering, we learn about the basic physics behind locks as well as some of the methods engineers use to limit water loss through the lock. (Image and video credit: Practical Engineering)
September 14, 2020
The Engineering of Culverts
Manmade infrastructure often interferes with natural waterways, which is one reason civil engineers turn to culverts, those pipes and concrete tunnels you often see beneath roadways. As simple as they may seem, there’s a lot of engineering that has to go into these artificial waterways to keep flows from backing up and flooding roads. In this video from Practical Engineering, you’ll learn about some of those factors and see through demos just how they impact the flow. (Image and video credit: Practical Engineering)
July 31, 2020
How Spillways Work
Human infrastructure like dams have the challenge of standing up to whatever nature can throw at them. It’s expensive, if not outright impossible, to build to every single contingency, so engineers have developed methods of dealing with problems like excess flow caused by a storm. For dams, one of the ways of dealing with this are spillways, which allow a method of controlled release from a reservoir.
Spillways come in many shapes and sizes, as seen in the video, but there are two general types: those that are actively managed and those that are automatic. An automatic spillway is like the “morning glory” type seen in the middle animation. There’s no on or off for a spillway like this. Instead, once the water level is high enough, water naturally flows out. In that sense, it’s like the overflow holes found in many bathroom sinks.
Controlled spillways are usually managed with gates that can be opened or closed as operators need them. This technique gives more granular control and can even end up being cheaper in some situations because it requires less space to implement. (Video and image credit: Practical Engineering)
June 14, 2019