When you receive approval from your city or county planning department for your construction project, they will likely include requirements to build a swale on the land. A swale is a commonly used term in modern water management, but using swales to capture groundwater effectively has been around for over a century.
In fact, President Roosevelt directed laborers–the Civilian Conservation Corps—to build hundreds of miles of swales in Arizona during the 1930s to trap water runoff and enhance the soil to encourage plant growth. Here’s a video to show how plant life is flourishing in these swales 60 years later.
What is a swale?
Most land has some slope, often illustrated with contour lines on plot maps. Of course, water runs downhill. For homeowners living on sloped property, unmanaged ground results in waste as applied water quickly runs downhill to culverts, storm drains, or creek beds. As communities have become more conscious about conserving water, additional regulations for installing swales have become common.
To understand how a swale works, imagine a cross-section of land with a bit of a slope. Planners mark the position of the swale depending on the contour of the land. Now imagine a trench of between 6 inches to 1.5 feet deep is dug into the cross-section of land. The actual depth will depend on many factors relevant to the land itself.
The bottom of the trench must be level. As water flows downhill, it drops into the channel and then stops on the level bottom. Instead of flowing quickly on the ground’s surface, the water soaks into the soil and flows downhill but deeper and slower. To further enhance the trench, the dirt dug out of the trench is applied to the downhill side of the trench (the “berm”), raising the height on the trench, so there is more room to hold water.
Homeowners can fortify the swale by planting trees or other plants on the berm. The plants will benefit from the water absorbed into the earth, and root structures will keep the berm’s soil in place.
In areas that experience high water flow, a french drain or similar system can be installed at the base of the trench to help drain excess water away from the area and prevent flooding.
How is a swale different than a ditch?
Swales and ditches are similar, but they serve different purposes. However, a ditch is meant to carry all the water away. Properly constructed ditches are sloped to create water runoff in the direction of a creek, pond, or wastewater runoff collection system.
On the other hand, swales are designed to absorb the water into the ground and allow it to slowly move in deeper layers of soil to provide much-needed water for plants, trees, grass, and shrubs near the swale.
Homeowners that use professionally built swales benefit because they need to apply less water to the ground during dry months of the year. Any watering required is absorbed into the ground to nourish plants and grass rather than running off to the lowest section of the property. Ditches, on the other hand, are limited to removing excess water during wet seasons.
Excavation Oregon can build your swale or other water management system.
When your building project requires clearing or moving land, Excavation Oregon is the team to do it! Based in Southern Oregon, we know the landscape and how to optimize the use of your property. Our crews are experienced, using top-of-the-line equipment to do the job right the first time. With Excavation Oregon by your side, you’ll rest easy knowing your land will be managed correctly, so your dream home or commercial building will stand the test of time. Contact us today to learn more about all the services we offer.