What Is the Purpose of Swales?

Have you ever noticed a swale and wonder what the purpose behind it is? Well, the swale is an excellent way to transfer water from one location to another. It helps deal with the stormwater without allowing it to cause any damage. 

It is a small channel that may also include native vegetation, trees, or grasses. The swale also plays an essential role in collecting water from driveways and other surfaces like roofs. 

Other than this, people also use it for desert-like areas that require irrigation. So, if you have to deal with stormwater frequently or want to make proper irrigation, we recommend you construct the swales. Further, you will get to know more about the swales. We will make you familiar with that what is the purpose of swales and how to make them.

Should You Construct Swales?

Constructing swale will be an ideal solution for you if you want to store or convey the stormwater runoff. Stormwater is usually challenging to handle, but with the swale, it becomes manageable. 

You can minimize the movement of water and make it flow in the right direction with the help of swale. It will also help you easily remove the pollutants. 

During the dry season, the swale only holds little water. Once it gets heavy rainfall, the water will move in the swale. However, the flow of the rainfall water will be slow because of the grass present in the swale. It also filters the organic matter and breaks it down naturally.

Advantages of Swales

Following are some of the benefits of swales.

  • It will help you quickly connect to the landscaping.
  • With the help of swale, you can minimize the pace as well as the volume of stormwater.
  • You can easily locate the blockage and pollution if you have swale constructed.
  • Swale is an ideal way to get rid of urban pollutants.
Disadvantages of Swales

Though swale is helpful, it has a few disadvantages as well. The following points will let you know about the weaknesses of the swale.

  • If you have a steep area, then the swale will not be suitable for you. Avoid constructing the swale in a steep area. Apart from the steep area, you should avoid building swale on an area with roadside parking.
  • You might also find it challenging to grow trees in the swale.
  • The swale might cause difficulty in the pipework.
How to Construct Swales?

Constructing swales is not easy, but you can make it less complicated if you know the proper process. Besides, before making the swales, make sure that you have the budget, right location, and proper knowledge so that you do not have any issues in the process. So, follow the given steps if you plan to construct swales.

Step 1: Check the Water Site

The first thing you need to do is to examine the water on your site. Make sure to observe the water flow so that you can make the right decision. You should also have proper knowledge about your yard. 

Learn that from where the water is coming. You should also examine the exact location where the water is going. Furthermore, learn the drainage patterns of your area, which will help you know the exact location where to construct the swales. 

Also, observe the steep slopes and find annual rainfall to know that rainfall occurs more at what time of the year. If you want, you can even make a whole-system water plan that will make things more manageable.

Step 2: Locate Suitable Location for Permaculture Swale

Locating a suitable place for permaculture swale is another essential thing to do before starting making swales. A permaculture swale will help you store the rainwater and use it to irrigate the planting area. Before choosing a suitable location for permaculture swale, you will need to follow some rules given below.

  • Ensure that the swale is around 10 feet away from the building, which will protect the building from any damage. Also, ensure that water drainage should also be away from the building.
  • Other than this, also check how far the swale is from a steep slope. Try keeping the length of the swale from a septic drain field or the steep slope around 18 feet away.
  • Also, examine the infiltration rate before starting the process. Make sure that this rate is at least 1 inch per hour.

These are the rules you should keep in mind if you want to select a suitable location for permaculture swale. However, keep in mind that if you live in a place with a high water table or a highly steep slope, you should avoid this strategy as it might not work in that case.

Step 3: Make Contour Line

After that, you will need to make contour lines. For this process, you can utilize a contour level and a utility flag. Both the utility flag and contour level will make the marking easier. Other than this, you can also use the A-frame level if you want. 

Further, make sure that the line is after every 6 feet. Make sure that the lines are accurate so that you get the best result. If the contour lines are not correct, you might end up building the wrong swale. Therefore, be careful with the contour lines.

Step 4: Dig a Trench

What Is the Purpose of Swales?

Once you are done marking contour lines, the other thing you require is to dig a trench. The marked contour lines will help you in digging a trench accurately. You can adjust the depth and width of the trench as per your wish. 

However, it is recommended to keep the depth of a trench to around 6 inches to 1.5 feet deep. Other than the depth, carefully choose the trench width. Mostly trench comes with a width of around 18 inches to 2 feet. 

The length of the trench depends on various factors. You will need to consider the available space and your requirements while constructing the trench length. Therefore, you can vary the length of the trench as per your need.

Step 5: Make A Berm

After digging the trench, you will extract soil from the ground. You can mound the soil after digging it from the trench and make a berm using it. Make sure to put it on the downhill side. Try making a berm on both sides of the trench.

Step 6: Test the Swale Level

Now you will require checking the level of the swale. Various materials are available that can help you in this task. We would prefer you choosing the A-frame level as it will make testing the swale level much easier. 

Upon testing, if you notice any uneven spots, make sure to fix them. It is also recommended to test the swale when it is raining heavily because, at that time, you will know the durability of your newly constructed swale. If the swale gets overflowed, you will need to make it wider, deeper, and longer.

Step 7: Plant the Swale

What Is the Purpose of Swales?

After that, you will begin the plantation of the swale. Make sure to choose perennials that grow permanently. You can also prefer those plants with thirsty roots, which will help you keep the system stable. 

If you live in a desert area, you will require planting the plants in the swale trench. On the other hand, if you live in a non-desert area, make sure to plant the berm.

Step 8: Build Redundancy

Once you are done with planting the swale, the other thing you require is to construct the redundancy in the swale system. You should also know where you will waste the water if the swale overflows. 

Try building a redundancy that can withstand heavy rain events. Ensure to have a proper plan so that you construct proper swales.

Step 9: Add Aesthetic Details

Do you want to give a better look at your swale? If yes, then you should also focus on the aesthetic details. In residential spaces, people usually focus more on the aesthetic details. 

Make sure that the swale is visually pleasing. You can also use wood chips or gravel to fill the trench, which will help you make a better walkable pathway. Other than this, you can also add large rocks to make it seem more elegant. 

You can add a rock border to the berm. It is up to you what you want to do to add more aesthetic details to the swale. So, these steps will help you construct the swale. The best thing is swale does not require much maintenance.


If you want to control water flow and maintain the water quality, then try constructing the swale. The swale will also give a better look to your landscape and keep you free from the stormwater. 

It will also protect the surface from erosion. However, before starting making the swale, make sure to examine your property properly. Examine whether you have sloping or linear land and check whether it will be appropriate to make the swale in your area or not.

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