Flood Control Explained: What is a Tilting Weir?

(Photo credit: Martin Childs Ltd)

Effective flood control depends upon proven tools and new technologies we use every day. Some of these tools, like our pump station, use modern innovations to manage large capacities of water in extreme conditions. Others leverage timeless mechanical principles and only a bit of the latest tech. A tilting weir is an example of a tried-and-true tool that’s still effective today.

If you’ve read our fall newsletter, you’re probably already familiar with IFCD 3’s initiative to add a new tilting weir to Valley Ranch’s flood control system. As we continue to work on this project, we wanted to explain the tilting weir and how it will enhance flood control and prevention in our community.

First, What’s a Weir?

It’s important to start by explaining a weir. A weir is a small, dam-like structure that can control how water flows in a river or moving body of water. Weirs often are deployed to adjust the water level of a river to prevent flooding. They’re also used to generate power, direct water flow and serve as a spillway for dams.

What Does Tilting Do?

A more specialized weir can be equipped with hydraulic motors that allow it to tilt. This added functionality gives the tilting weir operator greater control. The operator can make incremental, more precise changes to the water level and flow in the system to reach the desired conditions. The operator also can use a tilting weir to prevent backflow and flooding when downstream water levels rise.

How Will It Help Valley Ranch?

Once installation is complete, the tilting weir will help us drain water more efficiently from our sump to the Elm Fork of the Trinity River. We also expect to activate the pumps less often, which not only prevents wear and tear on the pumps but also conserves energy and lowers expenses.

IFCD 3’s board approved this system addition last year, and the project currently is underway. Valley Ranch’s new tilting weir is expected to be installed and fully functional later this year. Want to see a weir in action? Check out this video from Practical Engineering for a deeper dive into the physics behind this timeless tool.

To stay up-to-date on our flood control news and project updates, follow IFCD 3 on Twitter and Facebook. Plus, explore our Waterways blog for more interesting facts about flood control.