Mitigating Retail Center Stormwater Issues

Retail centers are community hubs for essential shopping and other activities. Still, their design and tenant mix often pose stormwater management challenges. If not managed properly, these centers can generate significant amounts of pollutants that enter stormwater systems, causing problems ranging from blocked drainage to harmful impacts on aquatic and environmental health. There are numerous challenges, but with essential mitigation strategies, retail centers can manage them effectively to maintain a sustainable, clean environment.

Challenge: Large Areas of Impermeable Surfaces

Retail centers often have extensive asphalt or concrete areas, such as parking lots, rooftops, and sidewalks. Stormwater does not soak into these surfaces, which generates increased runoff from the property into the stormwater system. Large parking areas and rooftops can generate significant runoff that quickly overwhelms a retail center's storm drains, resulting in pooled water near building entrances and parking lots.

To address these issues, embrace effective strategies for mitigating stormwater issues in retail centers, such as upgrading paved areas. Replace standard asphalt and impermeable concrete with permeable pavement types to allow more rainwater to soak into the ground. Additionally, property managers can add bioswales or rain gardens to landscaped areas of the property to retain stormwater and enhance infiltration. To reduce rooftop runoff, consider implementing green roof technology, which generally consists of adding vegetation and growing medium over a waterproof membrane on building roofs to absorb rainwater. This strategy provides added insulation benefits, which can reduce energy costs.

Challenge: Higher Pollutant Loads

Stormwater from retail centers, mainly parking lots, carries pollutants such as grease, oil, heavy metals, garbage, and other debris into stormwater systems. Runoff containing these pollutants goes directly into local waterways through the stormwater management system without additional treatment or filtering.

To address this issue, partner with a commercial storm drain cleaning company to implement a regular maintenance schedule, which ensures debris is consistently removed and drains remain clean and open. Storm drains should include catch basins equipped with filters for sediment and debris and oil-water separators to filtrate the different types of pollutants. Implement regular street sweeping and other maintenance techniques to remove garbage and pollutants from parking lots before storms hit to keep them from entering the stormwater system.

Challenge: High Foot Traffic and Littering

Retail centers experience high foot traffic and typically sell packaged food, snacks, and beverages, which contribute to litter and debris accumulation. Plastic bottles, food wrappers, and other garbage often collect around busy entrances and seating areas. If not routinely cleaned up, the trash and debris can wash into storm drains, causing clogs, blockages, and potential flooding.

To mitigate these problems, retail centers should provide additional trash and recycling bins in critical areas and have them emptied regularly. Educating tenants and customers on proper waste disposal practices and implementing regular staff litter patrols to keep areas clean is also essential.

Challenge: Delivery and Loading Areas

Frequent deliveries and loading activities make retail centers more prone to pollution from leaks or spills of oil, fuel, or other hazardous materials. If not contained and cleaned correctly, these spills can contaminate stormwater runoff. During rainstorms, spilled contaminants can wash into the stormwater system, so it is essential to deal with spills appropriately when they happen. Loading areas can also accumulate large amounts of packaging materials, litter, and trash that can end up in the stormwater system.

Practical strategies for mitigating stormwater issues in retail centers can address these challenges. Develop maintenance routines to regularly clean and maintain loading areas to remove accumulated spills, debris, and other pollutants. Develop protocols to contain spills and implement proper drainage controls, such as spill kits or berms. Additionally, training staff on appropriate spill response is essential. Ensure the area has adequate waste and recycling containers that are regularly emptied, and enhance drainage systems with measures to capture and treat pollutants to filter them out of the stormwater.

Challenge: Seasonal Maintenance

Seasonal activities like landscape maintenance and snow removal in retail centers can introduce additional pollutants into the surrounding environment. Fertilizers and de-icing chemicals like salt can be washed by rainfall into storm drains, contributing to increased chloride levels and other contaminants in nearby lakes and streams. Most de-icing substances are corrosive, damaging cars, roads, bridges, and other retail center infrastructure. Fertilizers can also contaminate stormwater, negatively affecting aquatic life downstream.

To remedy these issues, centers can use alternative de-icers and improved runoff management techniques to keep de-icing chemicals out of stormwater systems. They can also use organic or slow-release fertilizers to enhance their landscapes with native plants. These plants often require less fertilizer or pesticides as they are adapted to the environment.

Challenge: Illegal Dumping

Retail centers face issues with illegal dumping of chemicals or waste due to easy access to dumpsters, storm drains, and other waste disposal mechanisms. Individuals may take advantage of this to avoid disposal costs or disguise the source of the pollutants to avoid accountability. Waste oil and other pollutants are also illegally dumped into retail center storm drains due to negligence or a lack of disposal facilities. This action is very harmful and can cause widespread contamination of local rivers, lakes, and other water bodies.

To minimize illegal dumping, increase signage and surveillance, such as placing security cameras around vulnerable areas, to deter illegal dumping and identify any violators. Regular patrols and improved infrastructure such as covers, grates, and locking mechanisms can offer further protection. Partner with waste management companies to provide affordable, regular waste-removal services and work with local authorities to monitor locations and address reported incidents. Educate tenants on proper waste disposal procedures specific to their business needs.

Challenge: Tenant Practices

Retail centers have a variety of tenants, each with unique practices that may contribute different types of pollution to stormwater. Restaurants and food retailers may pollute with food waste, grease, and cleaning chemical residues. At the same time, car maintenance shops have pollutants such as motor oil, antifreeze, and brake fluid. Tenants such as pet stores, home improvement stores, and a garden center increase pollution risks due to increased organic waste, paints and solvents, construction debris, animal waste, and herbicides or pesticides.

One practical mitigation approach is to develop tenant-specific stormwater management plans with guidelines tailored to each business's pollution risks. Build clauses into lease agreements and clearly state the consequences of non-compliance, such as penalties or lease termination. Perform regular site inspections or audits to ensure that tenants are complying. Provide training and information on best practices and methods for pollution prevention, waste management, and stormwater protection. In addition, improve onsite infrastructure, such as adding specific waste-disposal and recycling areas, sediment traps, oil-and-water separators, and vegetated swales to ensure pollutants are filtered out before runoff enters the stormwater system.

Challenge: Minimal Green Space

Many retail centers are designed with large parking lots and paved areas, leaving little green space to aid in stormwater infiltration. This results in increased runoff volumes that flow directly into storm drains. The water volume can overwhelm the stormwater system, potentially flooding the retail center and surrounding streets.

As one of the effective strategies for mitigating stormwater issues in retail centers, property managers can enhance the grounds with green infrastructure, such as vegetated swales, planted tree boxes, or small park areas that capture and filter stormwater. Additional solutions include adding vegetated buffers around loading docks and parking lots to intercept and absorb stormwater before it enters storm drains. Plant trees on the sides of walkways, as they provide shade, improve the center's aesthetics, and intercept rainfall, allowing it to soak into the soil instead of storm drains. Replace areas containing traditional green lawns with ground cover, shrubs, and native plants that can more effectively filter rainwater to remove pollutants. They also usually require less water, fertilizers, and pesticides, making them eco-friendly solutions. These strategies can add to the property's aesthetics in addition to treating and managing stormwater more effectively.

Take Action to Improve Stormwater Management

Effective retail center stormwater management requires a proactive approach. Scheduling regular catch basin cleaning and other maintenance activities improves stormwater management. Contact CatchAll Environmental today to see how we can help you put your stormwater maintenance on auto-pilot.