Harnessing the Power of Swales: Small Dams with Big Benefits
Ever wonder what makes water stop in its tracks? For many, the answer might be dams—those massive structures we've built around the world to control and manage water flow. While that’s certainly true, there’s another, more localized approach you might not have considered: swales.
Swales are essentially small, meaningful dams designed to hold and slow water in place. Unlike the towering concrete dams we’re used to seeing, swales are simple, versatile, and can make a huge impact—especially in places like Sierra Vista. Curious about how they work and why they matter? Let’s dig in (pun intended).
Why Build a Swale?
The benefits of swales are numerous, particularly in areas prone to water runoff or drought. Here’s why they’re worth considering:
Free Water Management: Swales stop water in place and allow you to use it naturally—no cost, no complicated systems required.
Recharging Groundwater: Water that sinks into the ground from swales contributes to the local water table, benefiting not just your property but the surrounding environment.
Efficient Gardening: If you’re into sustainable gardening, swales can reduce your water usage. You can design them to be any size you need, perfectly tailored to your space and goals.
Getting Started with Swales
Creating a swale is simpler than it sounds. Start by assessing your needs and determining where water tends to flow on your property. Once you’ve identified the right spot:
Dig a trench along the water flow.
Use the soil from the trench to build a berm (a raised wall) on the downhill side of the trench.
Consider incorporating organic matter—such as straw or chopped leaves—into the soil to enhance water retention.
Tools You’ll Need
A shovel, broad fork, or even a rototiller will get the job done. For larger projects, heavier equipment might be helpful, but for most backyard-scale swales, simple hand tools are all you need.
Types of Swales
Swales on Contour
These swales follow the natural curve or slope of the land, and are dug so the ditch is level while curving horizontally with the slope of the land. On steeper slopes, multiple swales are placed closer together to capture water effectively. On flatter land, they can be spaced farther apart to allow rainwater to soak into the ground gradually.
Key tips:
Keep the sides of the swale flared—three to four times wider than their height.
Ensure the bottom is flat, and the walls have a gentle slope.
Smile Swales
These swales have been used for centuries and remain a powerful tool in combating desertification. For example, they’re being utilized on a large scale south of the Sahara Desert to prevent its spread.
A simple design features a half-circle berm, which determines the swale’s size, usually 15 feet or 5 meters at the “opening”.
Compound smile swales can include rectangles or depressions in front of the berm for even greater water storage and absorption.
Why Swales Work
Swales slow the flow of water, allowing it to sink into the soil rather than running off. Over time, this helps restore the land, recharge aquifers, and support plant growth—all while preventing erosion and runoff.
Ready to Build Your Swale?
Whether you’re looking to enhance your backyard or contribute to a larger sustainability effort, swales are a practical, impactful solution. By embracing this ancient but effective technique, you can manage water naturally, support local ecosystems, and even grow your garden with less effort.
Start small, dig deep, and watch the benefits flow!
