As a property manager in St. Louis, you know the importance of stormwater maintenance. Without it, you would experience flooding and erosion. Stormwater is not simply rainfall. It is runoff from the impervious features of your property: your parking lot, walkways, your building, or anything that gets in the way of rain’s natural path where it can be filtered naturally.
When water runs off roofs or parking lots, it carries with it debris, sediments, toxins, and pollutants. Think about how pristine, white snow quickly becomes a mass of thick, gray sludge after a few days in a parking lot. All of those chemicals and pollutants wash away from the lot as the snow melts or rain falls and makes their way to your bioswale where the toxins are filtered out through the vegetation, stones, soil, and other media. Without your bioswale, they would flow into the beautiful St. Louis streams, creeks, and aquifers. In order to protect the waters of St. Louis, the Metropolitan St. Louis Sewer District requires that businesses follow their Best Management Practices (BMP), which are guidelines for managing stormwater runoff. These include depressed areas of landscaping called bioswales designed with gently sloping sides and vegetation, stones, and soil that filter the water that flows into them. Bioswales are separated into 3 zones. Native plants in the lowest zone are highly tolerant of standing water and the middle zone consists of native plants that tolerate areas that fluctuate in moisture levels. The highest zone has native plants that work well in fighting soil erosion and have a fibrous root system to hold the soil in place.
Once your bioswale has been installed, what do you do with it?
As with most things in life, without proper maintenance, it will eventually break down and be ineffective. In order to work properly and remain in compliance with BMP, your bioswale needs regular check-ups.
Newly installed bioswales need to be inspected after heavy rainfall to ensure they drain properly, as listed in the Inspection and Maintenance Schedule found in the Stormwater Management Facilities Report. If your bioswale has been installed recently, your plants need some help establishing themselves. They need to be heavily watered for the first 90 days and their growth should be closely monitored to determine whether or not they are thriving. While the bioswale is made to filter runoff and therefore should receive an abundance of water with each rainfall, it may need a little help at first. If plants are not healthy, it could be that they do not tolerate the growing area and should be replaced with ones that are better adapted to the growing conditions of your property. This is why it’s essential to use the correct and proper placement of native plants. It reduces having to replant.
Weeds can be a problem for bioswales, and they should not be confused with native plants. Native plants thrive in your area and create an ecosystem, living in harmony with other plants. Unwanted weeds take over and compete with your plants for resources like water, sunlight, and vital nutrients. A bioswale that is cohesive and well-established can better fight off weeds and they become less of a problem. Stay on top of the weed problem by manually removing them by the roots or with spot use of herbicide.
Drought can be a big problem for newly installed bioswales. During the prolonged dry times of drought conditions, plant material may require watering. Once the proper plants are established, however, they should be able to survive their native climates.
Conversely, flooding can be a big issue as well. If there has been an extreme flooding event, your bioswale should be thoroughly inspected for damage. Flooding can cause damage to the structure, clog inlets and outlets, cause banks to collapse, buildup of debris, sediments can clog the garden’s floor and cause plants to die, and restrict stormwater from draining properly. This is why it’s essential to hire a professional company with technicians who are trained in the maintenance of bioswales to perform regular inspections. They know what to look for and can fix the problem quickly.
Although low-maintenance native plants are used in bioswales, this by no means indicates they are no maintenance. It’s important to regularly check for weeds and your plants’ health, replacing them when needed. Some plants will require pruning to remove dead leaves and branches in order to initiate growth or cut back overgrowth. The plants in a bioswale are not for privacy; they are chosen for their ability to filter runoff.
Because the function of a bioswale is to filter stormwater runoff, it’s inevitable that you will have a periodic build-up of sediment and it should be checked for this quarterly and after a heavy rainfall to ensure proper drainage. Any litter or debris should be removed as well.
Bioswales are an important part of any landscape. They can add interest and character to your property, but more importantly, they direct and filter stormwater runoff, reducing flooding, reducing erosion, filtering harmful pollutants, lowering the volume of water entering the storm system, providing food and habitat for wildlife, and increasing biodiversity.
Bluegrass Landscape and Maintenance can install bioswales and maintain them. Call us today at (314) 770-2828 and find out how effectively manage stormwater runoff.