Swale drains, French drains, Trench drains, and Slot drains: which is best for you?
That depends on your application and your yard.
Slot Drains are best for hardscaped yards, patios, pool decks, driveways, and parking lots. They can accept high flow rates while remaining mostly invisible, providing excellent drainage without disrupting aesthetics or accessibility.
French Drains are best for removing excess moisture from softscaped yards. They are buried below the ground and allow moisture to seep into a concealed pipe and drain out of the yard.
Trench Drains are best for commercial and industrial applications with large volumes of liquids and solids. Trench drains are functional workhorses, but their wide grates disrupt accessibility and design aesthetics. Trench drains are also available with designer grates, but these often limit flow.
Swale Drains are best for large yards, parks, and conservation areas. They become shallow open ditches when it rains, and not everyone wants a creek running through their yard every time it storms.
Slot Drain System
A slot drain is a grateless linear drainage system with a narrow, elongated slot-like opening along the top, available in ½″, 1″, and 1 ¼″ widths. This inlet can accept flow rates of up to 27 GPM per foot of drain while diverting water into the large, pre-sloped body hidden underground. This setup lets slot drains manage high volumes of water, even from extreme rainfall events.
Designers and landscape architects often choose slot drains for their looks. On luxury projects, they can drain large areas while remaining nearly invisible to the naked eye. Even though they are minimalist, slot drains are still easy to maintain. Finding clogs and retrieving lost items is simple thanks to clever system design, including accessible catch basins and integrated strainer baskets.
Slot Drain Systems offers a range of slot drains. The versatile 7000 Series is the workhorse of landscape design. The 4000 Series has one flat side so it can be placed directly against a wall. The Radius Slot Drain is custom-curved to match flow aesthetics. The 6000 Series is designed to fit into shallow slabs where other drains are too deep. You can view the full range of Slot Drain Systems here.
It’s important to remember that slot drains need to be packed in solid substrate or encased in concrete, so they can only be used in hardscape areas. For softscape areas, French drains are a better choice.
French Drain System
(Photo by http://www.sacstatesnow.com)
The French drain system is one of the oldest and most well-known drainage systems still in use today. Contrary to its name, the French drain did not originate in France, but is named for its inventor, Henry Flagg French. French created this system as a form of “farm drainage,” and it has become the basis of all modern-day systems.
When water flows through soil, it tends to take the path of least resistance. If no water management is done, in terms of grading and landscaping, the water can end up pooling in the yard or near the foundations of buildings. Over time, excessive water leads to dead patches on the lawn and/or damage to buildings. A French drain creates a path of low resistance, diverting water away from problem areas.
A French drain is a subsurface channel made from a perforated pipe installed in a sloped trench and buried in permeable aggregate like river rock. This provides an easier route for the water to travel.
French drains keep wet yards dry. They collect surface and subsurface moisture, as water easily penetrates the gravel and seeps into the buried pipe. The pipe then carries the water from wherever the drain starts–usually close to the foundation of a structure–to where it ends, usually at a cistern, storm sewer, or swale.
French drain systems are designed to work with gravity, transporting water from the highest point to the lowest.
Trench Drain System
(Photo by https://emswcd.org)
Trench drains are often confused with French drains, but unlike French drains, which are subsurface systems, trench drains are surface systems.
A trench drain is a linear drainage system consisting of a trough-shaped channel covered with a grate. Trench drains and slot drains have similarities, but trench drains have a wide inlet with a grate, while slot drains have a narrow inlet with no grate. Just like slot drains, trench drains are embedded in concrete or packed substrate for structural stability. Trench Drains can be made from cast iron, plastic, fiber-reinforced polymer, or stainless steel.
Trench Drains are designed to manage large, sudden volumes of liquids and solids. Trench drains are placed outdoors for stormwater management and indoors to keep industrial settings safe and dry. Stainless steel trench drains have specialized grates that can handle very heavy loads like trucks and forklifts.
Trench drains are found in processing plants, shipping/receiving zones, and architectural landscape design. Hygienic trench drains are used extensively in food and beverage and pharmaceutical processing. Trench drains equipped with catch basins and strainer baskets can manage solids in places like potato processing plants.
Swale Drain System
(Photo by https://permacultureapprentice.com)
A swale drain is a shallow ditch lined with turf grass or similar vegetation. They are broad and shallow, which sets them apart from trench or French drains.
Swale drains control outdoor water runoff. They prevent flooding, puddling, and erosion of the surrounding soil. They also help keep storm drains (part of city stormwater systems) from being overwhelmed by a sudden influx of water. Because they are wide and shallow, swale drains spread water over a large surface, containing runoff so it can gradually drain into stormwater systems.
For a subtle drainage solution, swale drains are a great option to consider. They typically have a curved profile that starts from one edge and flows gently down and then up, allowing even extensive swales to look as if they are part of the sculpting of the surrounding landscape. Because of this, they are often used in residential and commercial areas, and even in sustainable landscapes as a means of water conservation.
QUESTIONS?
Do you have questions about how a drain system may benefit your commercial landscaping project? Contact one of our drainage experts today.
