How do you make a drainage swale?

  1. Step 1: Evaluate the Slope. Construction of a swale begins with analyzing the slope of the yard and water runoff patterns to plan the route for the swale ditch.
  2. Step 2: Lay Out the Swale.
  3. Step 3: Excavate the Swale Ditch.
  4. Step 4: Lay Gravel and Drain Tile.
  5. Step 5: Finish the Swale.

How deep should a drainage swale be?

Six- to 12-inches deep
Step Two: Dig It 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.

How do you size a drainage swale?

When constructing a swale with known side slopes, the width of the swale can be defined in terms of the depth. For example, 3:1 side slopes on a swale indicates that for every 1 foot of depth, each side slope will be 3 feet wide, for a total swale width of 6 feet.

What is a drainage swale?

A grass drainage swale is an open channel that collects water from hard surfaces and allows it to percolate into the ground, reducing the amount of runoff leaving the road or property. The grass covering the side slopes and swale bottom provides a filtration surface for the water and helps to reduce the flow velocity.

How do you make a permaculture swale?

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.

How do you calculate swale?

Swale Volume (gal) = 0.5 depth (feet) x width (feet) x length (feet) x 7.5 gal/ft3

  1. A = Catchment area in square feet (length X width)
  2. R = Rainfall in feet = Rainfall in inches / 12.
  3. There are about 7.5 gallons per cubic foot.
  4. Factor in the number of inches received in a high flow event.

When should you not use a swale?

Swales are not appropriate on steep landscapes. 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.

What is permaculture swale?

A permaculture swale is a shallow trench dug along the land’s contour, with a berm on the downhill side created with soil from the trench. All points along a contour line are exactly the same height above sea level.