A: A swale is simply a shallow ditch that is used to carry off water. Swales are often so wide and so shallow that you do not notice them. On most city lots, where homes are 10 to 15 feet apart, there is a swale between the homes. Such swales collect water from the roofs and yards and carry it to the street.
Q: WHEN SHOULD I USE A SWALE?
A: Advanced will install a swale if you have a surface drainage problem, and you have enough slope to use gravity to get rid of water. We like to use swales when possible because they are virtually maintenance free for homeowners. Because swales must slope downhill, they tend to be deeper as they get longer. For a relatively flat yard, a swale will generally drop 1 inch for every 10 feet of length.
If your yard is flat for 60 feet, and then drops several feet to the street, a swale starting in the back yard would begin at a depth of two inches and be 8 inches deep at the point where it reached the drop to the street. To keep the swale from being too noticeable, we would gradually widen it as it approached the front of your house.
Q: HOW DO I KNOW IF I NEED DRAINAGE SWALE?
A: If water stands within 10 feet of your foundation for more than an hour after rains stop, you may need drainage improvements. Swales are often the easiest drainage to install.
Q: WHAT ARE THE MOST COMMON USES OF SWALES?
A: The easiest way for Advanced to drain your foundation is to have gutters installed and for us to slope the ground away from your foundation. Typically a slope of an inch a foot for 4 to 5 feet is adequate, as long as water is not allowed to stand within 10 feet of your foundation. Away from the side of your foundation, water can be directed into a swale or into surface drains. If grading is not possible, area drains, drains that collect surface water can help. In some situations, shallow French Drains are useful.
Q: WHAT DOES A SWALE COST?
A: Correcting problems in existing swales can cost as little as $500.00. Larger projects start at $1,000. The cost goes up the longer and deeper the swale.