Bioswales – Natural Stormwater Management Systems
Urban development creates a critical environmental challenge: impervious surfaces like parking lots, buildings, and roadways prevent natural water absorption, causing stormwater to rush across these surfaces and collect harmful contaminants. This unfiltered runoff carries motor oil, heavy metals, fertilizers, pesticides, and road salt directly into storm drains and waterways, leading to contaminated drinking water sources, toxic algae blooms, and degraded aquatic ecosystems. Traditional stormwater systems simply channel this polluted water away without addressing water quality or restoring natural hydrological cycles.
Bioswales offer a better solution. These engineered landscape features capture and filter stormwater runoff at its source, mimicking natural wetland processes to remove pollutants through biological and physical filtration. By intercepting contaminated runoff and returning clean water to the ground, bioswales protect waterways while reducing flood risk and creating functional green space in urban environments.
How They Work
As stormwater flows into bioswale areas, it percolates through specially designed filtration media that removes pollutants including phosphates, nitrates, hydrocarbons, and heavy metals. Beyond water quality improvement, bioswales serve two additional critical functions: they reduce the volume of stormwater entering municipal drainage systems during heavy rainfall events, and they facilitate groundwater recharge by allowing filtered water to infiltrate back into the soil.
Plant Selection
Vegetation in bioswales is carefully chosen based on multiple criteria. Selected plants must slow water velocity as it moves through the system while actively absorbing specific contaminants such as heavy metals, nitrates, and phosphates. These species must also demonstrate resilience to extreme moisture fluctuations—thriving during both flood conditions and extended dry periods.
Soil Composition
Bioswale soil blends are engineered mixtures typically containing sand, compost, and clay in specific proportions. Sand comprises the largest component due to its high porosity, which enables efficient water filtration. Compost serves a dual purpose: it moderates infiltration rates to prevent water from passing through too quickly, while providing organic matter that supports plant growth and enhances pollutant capture through biological processes. Clay contributes essential minerals for plant health but is limited to less than 5% of the total volume—higher concentrations would impede water movement and compromise the system’s functionality.
Next-Generation Bioswales: How Country Oaks Transforms Recycled Materials into High-Performance Filtration
Country Oaks leverages recyclable materials to manufacture bioswale systems that outperform conventional designs while advancing environmental sustainability.
Recycled Glass Sand – A Superior Alternative
Our pulverized glass originates from residential curbside recycling programs. Through a two-stage hammermill process, we round all sharp edges and screen the material to a uniform particle size optimized for bioswale drainage.
Unlike conventional quarried sand composed of calcium carbonate, our glass-based medium offers distinct advantages. Traditional calcium carbonate sand leaches calcium as water passes through, elevating soil pH levels. This increase binds essential nutrients, making them unavailable for plant uptake—a significant problem since landscape designers typically specify lower pH ranges to maximize nutrient availability.
Glass sand, derived from silica, provides multiple benefits. Silica strengthens plant structure while maintaining a more neutral pH that keeps nutrients accessible. Additionally, the drainage characteristics of glass sand significantly exceed those of quarried alternatives.
STA-Certified Compost
Country Oaks produces compost certified through the U.S. Composting Council’s Seal of Testing Assurance (STA) program. Complete test results are available to all customers, documenting compost composition, maturity levels, pH, heavy metal content, organic matter, pathogen levels, and weed seed presence. Only materials meeting the program’s rigorous standards receive STA certification.
High-Performance Biochar
We manufacture premium biochar through the pyrolysis of northern Michigan red pine, yielding a high-carbon, low-ash product with exceptional cation exchange capacity. When incorporated into bioswale systems, this biochar effectively captures phosphorus, nitrates, hydrocarbons, heavy metals, and even PFAS compounds. Many captured pollutants are subsequently absorbed by bioswale vegetation, permanently removing them from the water cycle.
This filtration capability is critical for preventing nutrient overload that causes algae blooms and oxygen-depleted dead zones in downstream waterways and lakes.
Ready to Implement a Superior Bioswale Solution?
Country Oaks Landscape Supply combines decades of environmental expertise with innovative recycled materials to deliver bioswale systems that exceed industry standards. Whether you’re planning a new development, retrofitting existing stormwater infrastructure, or seeking STA-certified compost and engineered soil blends for your project, our team is ready to help.
Contact us today to discuss your stormwater management needs, request product specifications and test results, or schedule a consultation with our bioswale design specialists.