Construction sites that disturb one acre or more of land and discharge into public waters are required to develop a Stormwater Pollution Prevention Plan (SWPPP) when applying for a construction general permit. These plans are designed to limit the exposure of pollution with stormwater runoff to protect local environments.
When most people think of a SWPPP, they probably imagine a number of structural best management practices, such as silt fences and sediment basins. These practices are an essential part of your SWPPP, but you may not be aware of dozens of additional practices.
Site managers have an obligation to invest in or manage stormwater BMPs to ensure they follow proper protections and regulations under their SWPPP. The following is a list of SWPPP best management practices that are an important part of your SWPPP.
What Are Best Management Practices (BMPs)?
In stormwater management, we assign a number of best management practices (BMPs) to our stormwater management plans to optimize our efforts. These BMPs include structural and non-structural strategies designed to limit erosion, reduce pollution, and control the flow of discharge.
BMPs are selected based on the site’s unique requirements and local weather conditions. These BMPs are critical to preserving local environments, communities, and the safety of the work site and to complying with measures of the Clean Water Act.
Benefits of Implementing BMPs in SWPPP
BMPs are an essential aspect of any SWPPP and serve many functions.
- Environmental Protection: The primary goal of BMPs is to protect the environment by minimizing pollution, reducing erosion, and preventing flooding. By effectively managing stormwater runoff, BMPs prevent pollutants from entering rivers, lakes, and other bodies of water, protecting aquatic habitats and drinking water supplies.
- Regulatory Compliance: Construction and industrial sites are required to comply with environmental regulations such as the Clean Water Act. Implementing effective BMPs helps sites meet these regulatory requirements, avoiding potential fines and legal action.
- Improved Site Conditions: BMPs also improve site conditions by controlling erosion, reducing dust, and managing runoff. This not only enhances the appearance of a site but also makes it safer for workers and reduces maintenance costs over time.
- Community Relations: Proper stormwater management can improve relations with the local community by minimizing the negative impact of construction and industrial activities.
Types of SWPPP Best Management Practices
We typically divide BMPs into three different categories when planning a SWPPP:
- Structural BMPs
- Non-Structural BMPs
- Operational BMPs
1. Structural BMPs
When we most commonly think of stormwater BMPs, we think of structural BMPs.
Structural BMPs include physical structures or devices installed at a site to manage and treat stormwater. These practices capture, treat, control, or divert runoff to prevent pollutants from reaching water bodies and prevent flooding.
Uses and Examples of Structural BMPs
- Silt Fences: Silt fences are one of the most commonly used structural BMPs at construction sites. These temporary structures are designed to capture sediment and slow the flow of water. They are made with geotextile fabric that allows water to pass through and sediment to be filtered. Silt fences are most commonly placed on slopes and around the perimeter of worksites where stormwater flows through.
- Wattles: Straw and fiber wattles are rolls of thick tubes typically placed around storm drains or along banks or slopes. They are designed to filter out sediment and other pollutants as water passes through.
- Sediment Basins: Sediment basins are engineered structures that collect and store runoff, allowing sediments and debris to settle before the water is discharged. They are typically used on larger construction sites with significant earth-moving activities. Basins can be permanent or temporary.
- Check Dams: Check dams are small barriers constructed across channels or swales to slow down water flow and allow sediments to settle. These structures are often used in areas with steep slopes to reduce erosion and stabilize stormwater flow.
2. Non-Structural BMPs
Non-structural BMPs are policies and practices designed to minimize the generation of pollutants. These include planning, design, and education efforts that aim to reduce the impact of construction and industrial activities on stormwater quality.
Uses and Examples of Non-Structural BMPs
- Site Planning and Design: Proper site planning and design are critical to minimizing the impact of stormwater runoff. Policies such as phasing construction to limit erosion, minimizing land disturbance to a smaller area, or preserving native vegetation can aid in stormwater efforts.
- Good Housekeeping Practices: Good housekeeping practices are essential to reduce pollution at construction and industrial sites. These include keeping work areas clean, storing chemicals in covered areas, and properly disposing of waste.
- Public Education and Awareness: Training staff on proper SWPPP protocols can ensure that all of the above-mentioned planning and structural BMPs operate to their full efficacy.
- Spill Prevention Plans: A spill prevention and response plan is crucial for any site that stores hazardous materials. Proper personnel training and the use of spill kits can reduce the likelihood of contaminants being introduced into stormwater runoff.
3. Operational BMPs
Operational BMPs are additional practices and operational changes designed to reduce pollutant discharge. These BMPs focus on managing tasks to minimize their impact on stormwater quality.
Uses and Examples of Operational BMPs
- Street Sweeping: Regular street sweeping helps remove pollutants such as oil, grease, and debris from paved surfaces, reducing their potential to mix with runoff and enter stormwater systems.
- Dust Control Measures: During construction, dust can become airborne and eventually be washed into stormwater systems. Implementing dust control measures, such as wetting down exposed soil or using wind barriers, can help minimize this type of pollution.
- Stabilized Construction Entrances: Stabilized construction entrances, typically made of large gravel or other materials, help to shake off dirt from vehicles, reducing sediment transport. This helps keep roads cleaner and prevents sediment from entering stormwater drains.
- Concrete Washouts: Implementing regularly scheduled washouts will help limit the risk of mixing concrete with stormwater runoff, which can be extremely hazardous to aquatic life.
- Waste Management: Placing trash bins around construction sites, ensuring timely waste disposal, and having designated areas for hazardous materials all contribute to effective stormwater pollution prevention.
Challenges in Implementing BMPs
Installing and maintaining site-specific BMPs requires time, labor, and capital. The following is a list of common challenges that site operators need to overcome when implementing and maintaining SWPPP BMPs.
- Site-Specific Conditions: Selecting the right BMPs will depend on many specific conditions, such as the local environment and the site’s topography. An environmental consultant will determine the right BMPs based on their training and experience.
- Maintenance Requirements: BMPs often require regular maintenance to function effectively. For example, SWPPPs require that all site BMPs be inspected and repaired every seven days or after a major rainfall event. Other BMPs, such as sediment basins, require regular cleaning.
- Costs: All BMPs, whether it’s silt fences, phasing construction, or street sweeping, cost money. However, the return on investment by avoiding fines and maintaining positive community relations is always there.
- Training and Awareness: The success of non-structural and operational BMPs largely depends on the awareness and training of personnel, starting with the site manager, vendors, subcontractors, and anyone who interacts with the site during the land development and construction phases. A lack of understanding of the importance of these practices can lead to poor implementation and reduced effectiveness. Continuous training and education are crucial but can be time-consuming.
Installing and maintaining site BMPs is an essential part of stormwater management. For assistance, contact a qualified environmental consultant with experience in drafting a SWPPP and implementing each BMP.
FAQs
What is a SWPPP?
A Stormwater Pollution Prevention Plan (SWPPP) is a document outlining how a site will manage stormwater to prevent pollution using a series of best management practices.
How does a sediment basin work?
A sediment basin collects runoff, allowing heavier sediments to settle before cleaner water is released, reducing sediment pollution.
What is the difference between retention and detention ponds?
Retention ponds permanently store water and slowly release it, while detention ponds temporarily hold runoff to prevent flooding and then drain completely.