Understand Swale vs French Drain: A Comprehensive Guide

Do you want to know the difference between a swale and a french drain? Swale vs french drain is a common question for those new to lawn management. Whether you’re looking for an efficient and economical way to divert runoff or aiming for a greener and healthier home lawn, swales and french drains are powerful tools to achieve these goals.

Both systems structurally provide a way for water to be diverted away from areas, protecting your home and lawn, although there are a few key differences. In this article, we’ll explain the differences between a swale and french drain and how to know which one is best for you.

Differences Between Swale and French Drain

Specifications	Swale	French Drain
Typical Installation	Generally designed alongside roadways and other hard surfaces, like a ditch along the roadside or at the base of the retained earth.	Typically installed along the edges of a home or building foundation or within the lawn to manage surface runoff.
Design	Generally designed with an inherently low grade (between 0.5% and 2%) to allow surface water to slowly flow through	Typically designed with a very low grade (1/8″-1/4″) to funnel surface water through a perforated pipe.
Uses	Can be used for erosion control, water retention, and to temporarily hold, filter, and slowly release surface runoff.	Generally used to filter surface water away from building foundations, and reduce the saturation of the soil near the property line.
Maintenance	May require periodic de-silting, cleaning, enlarging, and/or straightening in order to maintain proper drainage.	Will require occasional auguring or trenching to inspect, repair, or replace the perforated pipe.

Swales and French drains are two very different options when it comes to controlling the flow of surface water around a home or other structure.

A swale is generally designed with an inherently low grade (between .5% and 2%) to allow surface water to slowly flow through it, while a French drain is designed with a very low grade (1/8″-1/4″) to funnel surface water through a perforated pipe.

The typical installation for each is also different. Swales are generally designed alongside roadways and other hard surfaces, like a ditch along the roadside or at the base of the retained earth. French drains, meanwhile, are typically installed along the edges of a home or building foundation or within the lawn to manage surface runoff.

When looking at the uses for each, swales can be used for erosion control, water retention, and to temporarily hold, filter, and slowly release surface runoff, while French drains are generally used to filter surface water away from building foundations, and reduce the saturation of the soil near the property line.

Maintenance is yet another difference between swales and French drains. A swale may require periodic de-silting, cleaning, enlarging, and/or straightening in order to maintain proper drainage, while a French drain will require occasional auguring or trenching to inspect, repair, or replace the perforated pipe.

Overall, both swales and French drains can be effective solutions for managing surface water runoff. The key is to understand the differences in their designs, uses, and maintenance requirements so that you can select the option that best meets your needs and budget.

Swale vs French Drain: A Definitive Guide

Swales and French drains are two of the most popular methods of water management on residential, commercial and agricultural properties. Understanding the differences between the two options can have a huge impact on the success of your landscaping project and can help prevent water damage to your property.

In this guide, we’ll take you through the basic concepts of swales and French drains, the tools and materials you’ll need to get the job done, and the pros and cons of each technique.

What is a Swale?

A swale is a shallow, elongated depression in the ground that’s designed to direct water flow away from an area. It may be created naturally by erosion or manually by digging the soil into a depression with a tool like a backhoe.

Swales typically have gently-sloping sides and usually a flat bottom. They’re usually designed to drain water from a single area and can be lined with vegetation to help slow erosion and improve water retention. Swales are often used to divert surface water runoff away from a house and out towards something like a retention pond, a ditch, or a dry stream bed.

What is a French Drain?

A French drain is also a method to manage excess water flow in a landscaping project. It involves installing a pipe with a perforated bottom and layers of gravel and stone around it, in a depression or trench in the ground.

When water accumulates in the drainage trench, it will fill the system and be piped to a collection area. French drains are typically placed along the foundation of a building to divert water away from the structure or at the base of a slope to help control erosion.

Swale vs French Drain: Tools and Materials

You’ll need different tools and materials for a swale and a French drain. Here’s a brief overview of the supplies needed for each:

Swale

• A shovel or spade, a wheelbarrow, and a mattock
• Compost or soil additives, depending on soil quality
• Rocks or wood chips
• Native vegetation

French Drain

• A shovel or spade, a wheelbarrow, and a post hole digger
• Perforated plastic piping
• A variety of gravel and stone
• Heavy fabric (for wrapping the pipe)
• Sand
• Plastic sheeting (to cover the drain)

The exact type of materials and tools needed will depend on your specific project, so be sure to do some research about your local climate and soil conditions.

Advantages of Swales and French Drains

Swales and French drains can both be extremely effective for managing water runoff. Here are some of the main advantages of each system:

Benefits of Swales

• Directs water flow away from buildings, roads, and other areas in need of protection from flooding and erosion.
• Can be used to transport surface water to areas of the landscape that need it.
• Aesthetically pleasing, often incorporated into landscaping designs quite naturally.
• Can help recharge groundwater because they are designed to capture and transport runoff into an area where it can slowly infiltrate into the ground.

Benefits of French Drains

• Highly efficient at diverting water away from a structure.
• Can be designed in many shapes and sizes to fit any budget or project.
• Improves soil and plant health by preventing waterlogging.
• Easy to customize, including adjustments to the pipe layout, the slope of the French drain, and the amount of gravel used.

Softscaping vs Hardscaping for Swales and French Drains

Softscaping is the process of planting vegetation and other organic materials in an area. This is usually done in swales, where vegetation can help limit erosion and better absorb water. Typical softscaping materials include native plants, shrubs, trees, sod, and soil additives like compost.

Hardscaping, on the other hand, involves the use of rocks, stones, and other non-organic materials. This is typically used in French drains to add more structural stability and improve drainage. Common hardscaping materials used in French drains include limestone, gravel, sand, and plastic sheeting.

Pros and Cons of Swales vs French Drains

In addition to the advantages of swales and French drains, it’s important to consider the cons of each system before making a decision. Here’s a quick overview of the pros and cons of swales and French drains:

Swales

Pros:

• Easy to install and maintain
• Inexpensive
• Improves water conservation and recharge groundwater
• Can be planted to minimize soil erosion and add aesthetic value

Cons:

• Installation can be labor-intensive depending on the size and scope of the project
• Timing is important – swales must be maintained in order to function properly
• May not be effective for unusually heavy water runoff

French Drains

Pros:

• Highly efficient for controlling water runoff
• Highly customizable
• Easy to install and relatively low maintenance

Cons:

• Materials and installation are more expensive than swales
• Can be unsightly when not properly maintained
• Heavy materials are difficult to rearrange and may need to be completely removed if the landscape design changes

Installing Swales and French Drains

Installing either a swale or a French drain requires a lot of effort and preparation. Here’s a quick summary of each installation process:

Installing a Swale

• Dig out the desired area to create a shallow depression.
• Improve soil quality and fertility with soil additives like compost.
• Add vegetation and mulch to reduce erosion and improve water infiltration.
• Construct any necessary retaining walls to keep plants and soil in place.
• Add rocks or wood chips to the sides of the swale to help slow water flow.
• Connect the swale to an appropriate drainage area.

Installing a French Drain

• Dig a trench in the desired area that’s wide enough for the pipe and gravel.
• Reach a depth of 1-2 feet below the quality soil line.
• Lay the perforated pipe in the bottom of the trench.
• Cover with an inch of sand and a layer of heavy fabric for additional protection.
• Add a 2-3 inch layer of gravel around the pipe.
• Cover the gravel with another layer of fabric and a layer of stones or large rocks.
• Cover with three inches of topsoil.
• Connect the French drain to an appropriate drainage area with a hose.

Frequently Asked Questions (FAQs) About Swales vs French Drains

Wrapping Things Up

When it comes to drainage solutions, a Swale and a French Drain have plenty in common. Both are effective at helping divert water away from an area. However, they do have their differences too. For starters, French Drains require trenches lined with gravel and a pipe filled with perforations, while Swales are simply flat, land-based channels. The drainage abilities of both are also very different. Swales will hold the water and help it spread, while French Drains are designed to channel the water away quickly.

In summary, the choice between Swales and French Drains will depend on your environment and the amount of water you need to drain. If yours is an area with flat land and with large amounts of rain or snowfall, then a Swale might be your best option. If, however, you need to drain a smaller area quickly, then a French Drain should be your choice. Either way, it’s important to understand the differences between a Swale and a French Drain before making your decision.