8 Ways to Control Stormwater Runoff on Your Property

If your home deals with excess water from roof downspouts and neighboring properties during storm events, redirecting or capturing runoff can provide better management. Keep on reading to learn about effective runoff mitigation tips that do not cost a bundle.

What Is Stormwater Runoff?

Runoff is excess water that the land cannot absorb. Impervious surfaces, such as sidewalks, streets and rooftops, connect to some sort of drainage so they do not collect runoff during rainfalls. In many communities, these drainage systems unload into natural waterways.

Is Stormwater Runoff a Problem?

When there are large volumes of stormwater runoff, storm drains can become overwhelmed and localized flooding can occur. Runoff picks up sediment and other pollutants, which can end up in nearby streams, rivers, creeks or ponds. It is also a waste because water that does not soak into soil cannot be used to recharge groundwater sources.

Why Should Stormwater Runoff Be Controlled?

Essentially, you want to manage stormwater runoff to decrease its volume and prevent pollution. When stormwater stays close to where it falls, the chances of soil erosion and the amount of pollutants that are carried to surface water are significantly reduced.

How Do You Manage Stormwater Runoff?

The U.S. Environmental Protection Agency (EPA) says that you can control stormwater runoff by slowing it down, spreading it out and soaking it into the ground. Here are some affordable solutions to do just that:

1. Use a rain barrel. A rain barrel is a low-cost system that collects runoff from your roof. It is attached to the end of a downspout and stores water that can be used for watering your garden. It comes in various shapes and sizes, and can hold around 50 gallons of water. A larger barrel can hold up to thousands of gallons. Unless you have a cistern, this relatively inexpensive and easy-to-install tank usually does not provide sufficient storage to notably reduce the amount of runoff that flows to your lawn during severe storms. Instead, it acts as a useful addition to other runoff mitigation systems to increase the amount of runoff that is captured.

2. Create a rain garden. A rain garden is a planted landscape that sits below the level of its surroundings. Situated in the path of runoff flow, it is designed to encourage the soil to absorb more rainwater. In the event of a storm, the runoff will accumulate on the surface of the rain garden and seep into the soil, filtering the water before it enters the local waterways.

In a rain garden, the natural soil is substituted for a mixture of topsoil, sand and organic compost. Its depth varies depending on the resources, although 18 inches is often considered the minimum. Placing a bed of sand or gravel underneath the amended soil is optional.

A rain garden can be an excellent solution for a widespread drainage issue in your backyard. Like rain barrels, it comes in many sizes and styles. A larger and deeper landscape will expectedly treat more runoff while a smaller and shallower landscape will treat less.

3. Add a downspout extension. Redirecting runoff can be as simple as adding a downspout extension. This device is typically made from polyvinyl chloride (PVC) or metal and attaches to the bottom of your existing downspout. Ideally, a downspout extension should carry rainwater runoff at least three to five feet away from your home. Bear in mind that not all properties are suited for redirection. For example, if the slope of your roof is too steep or your lawn is small in comparison to your roof, a rain barrel or rain garden is generally the better option.

Using a splash block at the end of the downspout extension is also good for directing the runoff away from the foundation walls and into a more appropriate area. This device is typically rectangular and has a close-ended side placed right underneath the downspout.

4. Use a compost blanket or soil amendment. When you add compost to urban and suburban soil, which is often dense and compacted, it reduces its density and improves its structure. As a result, the soil becomes more porous, thus promoting infiltration and reducing runoff. Soil amendments function similarly in terms of biochemical and structural benefits.

A compost blanket is a low-intensity method. You can either purchase compost from garden centers or get leaf mulch from pick-up sites near you. You can even recycle organic matter you already have on-site, such as grass clippings or mowed leaves on the lawn. This organic matter will break down and decompose in the soil, although it will take quite a while to see the change.

For a more intense approach, make use of heavy-duty soil amendment. It is more costly, but the results are more immediate and visible. You can either hire a landscaper or rent a rototiller to do it. Amending the soil offers a lot of benefits, including providing nutrients for plant recovery, lessening the amount of irrigation and improving soil drainage.

5. Build a swale. A swale is a dug-out, sloped ditch in a landform. It can be either natural or artificial. If the sloping landscape in your backyard creates a risk of serious erosion, you can build a swale to help channel runoff as it flows to a drain. When the downpour is modest, the mound on the downhill side of the channel causes water to back up into the swale just long enough for it to seep into the ground.

A swale can also be a decorative landscape feature, such as a dry creek lined with smooth stones. This is preferred in locations where grass does not grow well. In areas with frequent torrential downpours, swales typically require more sophisticated engineering.

6. Install a catch basin. A catch basin is a container buried in the ground to receive and distribute unwanted water around a home. Its top is open, but covered with a slotted grate to allow water to pass through while filtering leaves and other debris. On the other side of the basin, there are holes for attached pipes that transport water away from the basin and into a spot where it cannot cause damage to the property.

Depending on the size of the catch basin, this device should be about 12 to 18 inches away from the foundation. Meanwhile, the pipes should have a decline of ¼ inch per 8 to 10 feet. If the tubes are sloping downhill, you can dig the trench to a uniform depth. If there is no slope, then you need the trench to decline.

7. Use a French drain. A French drain is a trench dug in the ground in problematic areas in the yard. It consists of a perforated pipe enclosed in water-permeable fabric and then covered with layers of gravel or stones. The fabric is used to prevent weeds and other debris from blocking the holes in the pipe, whereas the gravel or stones allow the water from your gutter installation system to flow more freely toward a municipal drain or any other drainage location.

If your basement experiences recurring floods or your foundation has sustained damage, install this basic design around the perimeter of your home to effectively drain excess runoff.