When you think of weir boxes, you’ll typically think of measuring open flow systems, but that’s just the primary use of these handy tools. Weir boxes can also be used to measure the health of a dam in addition to serving as a capture point for any excess seepage from the larger dam structure.
Dams are vital structures that can fundamentally change the way an entire water flow operates. With such substantial changes in play, it’s absolutely essential for the dam to maintain peak condition for as long as possible. Learn how weir boxes can measure dam health and discover what you need to do to get an idea of a dam’s status.
Dam Seepage
While dams are meant to impound water, there’s always going to be a bit of seepage through the dam and its underlying foundation. While the seepage is typically accounted for in normal dam planning, it’s important to ensure that the seepage is only carrying water and not any material from the dam itself.
If the seepage is carrying dam material with it, it’s a sure sign that the dam is breaking down. After all, the dam should be staying in place entirely even if a bit of water is breaking through the cracks and the foundation. Catching seepage flows is obvious, but you also need a weir box to determine whether or not the seepage has dam material. Additionally, a weir box is needed to measure the flow rate to ensure water isn’t escaping too quickly.
Why You Need a Weir Box
When it comes to simply measuring flow rates, a flume is all you really need. They do a great job at documenting the trends and flow rates of dam seepage, but they’re specifically designed to pass solids, so they’re not effective for assessing whether or not any dam breakthrough is included within the seepage.
A weir box, on the other hand, can accomplish everything a flume can along with an added benefit. Not only will weir boxes provide you with flow rate measurements, but they serve as a capture point for breakthrough material as well. This is possible thanks to the upstream weir pool.
How Weir Pools Work
Weir pools are key for weir boxes to capture sediment. This is because they slow the flow down as it approaches the weir crest. When the water slows, the trapped sediment drops from the stream and lands behind the weir plate, where it builds up over time. This can actually be a hassle to deal with in other scenarios, but for measuring dam health, it’s exactly what’s needed.
If you’re looking to push your sediment collection efficiency even further, you can use overflow/underflow baffles, which condition the seepage flow even further before reaching the weir pool. Combine these baffles with a weir pool, and you’ll be in a good position to collect sediment within the dam seepage to analyze its composition.
Find Your Own Weir Box
Seeing how useful weir boxes can be for measuring dam health, it’s time to find one of your own that can keep track of a dam’s condition. That’s where Tracom can help. We have a wide selection of options available that can be customized for your specific needs regarding flow rates and composition. Contact us today to get started!
