How deep should swales be?

How deep should swales be?

There are no hard rules about the size of a swale, but the bigger it is the more water it can absorb during a rainstorm. Six- to 12-inches deep and 3- to 4-feet wide are typical dimensions. Smooth out the shape of the berm with a hard metal rake to form a planting bed.

Why are Swales bad?

Swales—in permaculture terminology—are built on contour, which means they run level across the landscape. Any area with more than a fifteen-degree slope (about 1:3.75) isn’t appropriate for installing swales, as the water saturation may cause slides, which could be dangerous.

How do you dig up a swale ditch?

The swale must slope downhill, and has to gradually get deeper, ideally sloping 1 inch for every 10 feet in length. It is best to map out the swale first on paper, and then to mark it on the ground with its runoff point at the end. Dig out the trench with a sturdy shovel.

Are swales effective?

Vegetated swales are most effective on soils that allow infiltration. If infiltration is desired, the underlying soil drainage rate should exceed 0.5 inches per hour. Drainage area and slope: Swales can be used to treat runoff from small drainage areas with up to 5 acres of impervious surface.

What is a natural swale?

A swale is a shady spot, or a sunken or marshy place. Such a swale may be either natural or human-made. Artificial swales are often infiltration basins, designed to manage water runoff, filter pollutants, and increase rainwater infiltration – green instances are the subterm bioswales.

Do swales work in clay soil?

I don’t mean to throw a wrench in the gears, but I put swales in heavy clay, and they do fine. They are slightly off contour, so they drain. They do turn into ponds sometimes, but it hasn’t seemed to be an issue yet. Definitely oversize them if you do install any.

Can you trench with a box blade?

If you’re digging a ditch, all you have to do is set the box blade at an angle and drive forward over where you want to place the ditch. If you need steeper walls, adjust the angle of the box blade so that the ripper jacks dig deeper into the ground and go back over it a second time.

How do you make a swale permaculture?

The general idea behind digging the swale is that it should be about three-times as wide as it is deep, and the berm—the pile of excavated dirt—should be mounded to create the upper part of the bottom side of the swale. Make sure that the base of the swale is level so that the water disperses evenly.

What is the best way to install a swale?

So, ideally, a swale will be installed at the highest point possible but still low enough, downslope, to catch water run-off. From here, spread the water out on level plain by extending the swale on contour for as long as possible, that way water can absorb evenly into the land downhill.

What are swales and how do they work?

Swales are simply ditches on contour (contour is a level line across the landscape), with the excavated soil from the ditch being placed downslope to form a berm. The purpose is to rehydrate landscapes, add texture and microclimates, and to be used as a tree growing system. You can also use swales to increase catchment for ponds.

Should I Fill my Swale trench with mulch?

If your swale trench doesn’t need to be walkable, consider seeding it with cloveror adding a layer of mulch to reduce evaporation. Note: I don’t recommend filling the trench unless the swale is in a highly visible place where aesthetics are important.

How do you level a swale in landscaping?

Using the marked contour line, dig vertically into the hill, piling the dirt on the downhill side of the swale. The depth of the swale should remain the same and can be measured from the established contour line then leveled with a water level or the A-frame later.


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