Water is essential to life and vital to the progress of civilizations. It's delightful to sit in on a warm summer day or to watch as it falls gracefully into a fountain basin. There’s nothing more peaceful than the sound of rainwater falling on a tin roof, or as relaxing as soaking into a hot bathtub at the end of a long, hard day.
However, water becomes an insidious foe when it starts pouring into your basement or collecting in sodden pools on your lawn.
Drainage, therefore, is a constant concern in landscaping. There are various devices designed to direct water over and through the landscape, each of which serves different purposes and has different benefits.
Sometimes, the terms can get confusing, especially if this is your first time navigating home drainage solutions.
Today, I’d like to clarify the difference between three of the most common water diversion mechanisms: trench drains, French drains, and swales. I’ll explain what each of these are and give you some tips to help you find the right one for your specific needs.
The value of good drainage solutions in your landscape
Investing in good drainage solutions is vital for maintaining the health and aesthetics of your landscape.
Here’s why:
Preventing Water Damage
Water accumulation can cause serious damage to your property. Poor drainage can lead to foundation issues, basement flooding, and erosion.
Properly installed drainage systems such as French drains, trench drains, and swales can mitigate these risks by efficiently directing water away from vulnerable areas.
Enhancing Landscape Health
Excess water can suffocate plant roots, lead to rot, and create an unhealthy environment for your landscape. When you have effective drainage solutions in place, it ensures that your plants and grass receive the right amount of water, promoting healthier growth and a more vibrant garden.
Improving Usability
Waterlogged areas can make parts of your property unusable, turning beautiful lawns into muddy messes. Good drainage solutions can keep your outdoor spaces dry and functional, allowing you to fully enjoy your yard, garden, or patio.
Increasing Property Value
A well-maintained landscape with efficient drainage systems can enhance the value of your property. Potential buyers appreciate the aesthetic appeal and practicality of a home with no drainage issues, making it a worthwhile investment.
Promoting Environmental Sustainability
Drainage solutions like swales support sustainable water management by promoting natural infiltration and groundwater recharge. By reducing runoff and erosion, you’re contributing to environmental conservation and responsible land stewardship.
Cost-Effective in the Long Run
While the initial cost of installing drainage solutions might seem high, the long-term benefits far outweigh the expenses. Preventing water damage, reducing maintenance costs, and increasing property value make it a financially sound decision.
Surface vs. Subsurface Drainage
Before we begin, let's explore some basic drainage concepts.
There are two main types of drainage in the landscape: surface drainage and subsurface drainage. In any given landscape situation, it’s important to first assess what type you are dealing with.
Here’s an overview of both types:
Surface Drainage
As a general rule, we use surface drainage to deal with rainwater, especially heavy rain.
Typically, in this situation, you want the ability to drain large volumes of water away very quickly to avoid flooding and erosion and to prevent it from going where it’s not wanted.
A good example of a surface drainage mechanism is a ditch on the side of a highway. Swales, flumes, and trench drains are also used in various situations to convey water over grass, concrete, or other media.
Subsurface Drainage
In contrast, subsurface drainage deals with groundwater. This can be water that percolates down into the soil from above or bubbles up on your property.
Here in the South, you might have seen groundwater entering a basement that contains a nasty orange substance called bacterial iron. We normally use French drains to deal with that kind of saturation.
Now, let's take a closer look at French drains, trench drains, and swales - and the differences between them.
What Is a French Drain?
Most people assume that the French drain was invented in France, but that’s not the case. It was actually named for its inventor, Henry Flagg French.
French was an American who practically invented the fine art of farmland drainage, mainly to remove waste-contaminated water from feedlots and help prevent disease. He wrote a book called “Farm Drainage” in 1859 that became the basis of modern drainage.
The French drain is a true subsurface structure meant to address water that saturates the soil. Water will always seek the path of least resistance. When water flows through soil, it's typically under a lot of hydrostatic pressure.
Often, there will be a harder layer of soil or even rock under the top layer of soil. In this case, the hydrostatic force pushes the water both downward and transversely, which is why it’s so common for water to move sideways through a foundation.
When water comes to a foundation wall, it tends to seep through any chink or crack in the mortar.
A French drain works to keep your basement dry by diverting water from the surrounding soil into an underground barrier trench containing a gravel bed. Water is driven there because the voids in the gravel make it easy for it to travel through, making the gravel bed the path of least resistance.
The water then flows into perforated pipes at the bottom of the trench. From there, it is eventually discharged to an outlet, such as a swale, storm sewer, irrigation cistern, or sump. The entire system has to be designed to accommodate the natural flow of water from higher ground to the lowest point.
T. Lake’s French Drain Secrets
I can’t mention French drains without bragging a bit about our methods - because we include a few extra features that most companies don’t:
- Access Points/Cleanouts: We include access points or cleanouts on the lines to facilitate maintenance and prolong the life of the system.
- Separate Downspouts: If we pick up downspouts along the way, we send that water to a separate pipe, so it doesn't backflow into the drainage system.
- Root Intrusion Prevention: The most common problem with French drains is root intrusion; we use a filter fabric as a preventative measure to help keep roots out of the system.
- Heavy Duty Pipes: When installing a French drain under a driveway or road, we use heavy-duty structural corrugated drain pipe, not the stuff from the big box stores which can collapse if a truck drives over it.
- Proper Depth: We also bury our French drains at least 12”-18” deep to avoid collapse.
Does it add to the cost to do it this way? Well, it depends on how you look at it.
When you consider the cost of re-doing a French drain - including all the excavation and disruption to the landscape - we think it’s well worth it to do it right the first time.
What is a Trench Drain?
There’s a lot of confusion between French drains and trench drains because they sound so similar and because the French drain does incorporate a trench. However, unlike the French drain, the trench drain is a surface drainage structure.
A trench drain is a device designed to intercept and collect surface water over a long expanse. It is literally a trench with a grate on top. Trench drains are usually employed across a paved area to drain and direct water away from these surfaces. You see them a lot around commercial buildings like restaurants or loading docks to help keep the pavement in these areas dry and slip-free.
Even though a trench drain is embedded in the ground, it is technically a surface drainage mechanism designed to clear water away fast.
Under the grate is typically a plastic box-shaped trench that acts as a hidden surface water conveyance. A trench drain can be heavy-duty and wide, ranging down to the inch-wide micro drains you’ve probably seen in pool decks.
What’s Better, a French Drain or a Trench Drain?
There’s no single best answer to this question - it depends on the application you need the drainage for. A French drain is ideal for subsurface water issues, particularly if you have problems with basement flooding or groundwater issues. It diverts water away from the foundation, while a trench drain is meant to deal more with surface water issues (like heavy rain run-off in paved areas).
French drains require more complex installation (digging a trench, laying a gravel bed, installing perforated pipes). It’s more permanent and can be more costly to install since it requires more precise planning. Trench drains can be quicker to install, but require regular maintenance. If you don’t regularly clean the grate and trench, you’ll find that they become easily clogged.
French drains do need some maintenance - you’ll need to watch out for root intrusion and sediment buildup - but aren’t as needy as trench drains.
Ultimately, if you are dealing with groundwater or basement flooding, a French drain is your best bet. If your issue is surface water pooling, especially in paved areas, a trench drain is the way to go.
What is a Swale?
Like a trench drain, a swale is a surface water drainage device. However, it’s a lot more subtle in terms of its appearance in the landscape.
A swale is like a ditch, but it’s broad and shallow, and usually covered or lined with turfgrass or other vegetation. The purpose is to slow and control the flow of water to prevent flooding, puddling, and erosion and/or avoid overwhelming the storm drain system.
Any time we can spread water out, we slow it down, and it will percolate naturally into the soil. In fact, this is one of the main differences between a swale and a ditch - ditches tend to be deeper and to concentrate the water flow, increasing its speed and volatility.
Swales are very handy when you don’t want your drainage system to be obvious. A typical swale has a parabolic profile, starting at one edge and gently flowing down and up. You can do one so broad and shallow that it looks like part of the sculpting of the landscape.
For this reason, swales are often used in residential or commercial settings where there are large expanses of turf. You can also use them in sustainable landscape applications for water conservation.
Is a Swale Better Than A French Drain?
When you’re comparing swales to French drains, know that it’s really an apples and oranges situation - each has different applications and advantages depending on the context in which it’s being used.
A swale is best for managing surface water over large, open areas, and is ideal for settings where a natural look is preferred. A French drain is going to be better for subsurface water issues, particularly where groundwater is a problem or you need to protect foundations from water damage.
Remember, a French drain primarily focuses on diverting water away from problem areas, which is effective at resolving specific issues but might not contribute to groundwater recharge like a swale does.
Comparing Drainage Solutions
So how do you decide which kind of drainage solution is best for you? The decision is going to depend on several factors, including the type of water problem you’re facing and the layout of your landscape.
Here’s a quick comparison to help you decide:
French drains:
- Are best for subsurface water issues.
- May be ideal for preventing basement flooding.
- Require more complex installation.
Trench drains:
- Are best for surface water issues.
- May be ideal for paved areas and commercial settings.
- Are easier and quicker to install than French drains.
And finally, swales:
- Are best for surface water issues in large, open areas.
- Are ideal for residential and sustainable landscapes.
- Can blend seamlessly into the landscape.
Can You DIY Your Drainage Solutions?
While it’s possible to tackle drainage solutions on your own, we strongly recommend against it.
Proper installation requires specialized knowledge and equipment to make sure your solution is both effective and durable. It’s simply not worth it to invest all the time and energy in DIYing your drainage solutions only to find out you’ve made a mistake or installed something incorrectly.
After all, incorrectly installed drainage systems can lead to more significant issues down the line, causing more damage and expense.
Why not leave it to the professionals instead? Our team is experienced in assessing drainage needs and implementing the right solution tailored to your property.
Got Drainage?
If you’re dealing with water issues on your property, installing a French drain, trench drain, or swale could be just the solution you’re looking for. However, every property is different, and there are other solutions available as well.
Why not have us take a look? We’d be happy to come out, evaluate your situation, and suggest options that fit your needs and budget.
You can reach us at 478-750-7733, or contact us online to get in touch with one of our landscape drainage experts.
Don’t wait until water becomes the enemy - take action today and protect your property with the right drainage solution.