Sediment is usually the main pollutant of concern; according to the EPA, sediment runoff rates from construction sites are typically 10 to 20 times greater than the rates from agricultural lands, and 1,000 to 2,000 times greater than those of forest lands. In fact, during a short period of time, construction sites can contribute more sediment to streams than can be deposited naturally over several decades. In addition, common construction materials may contribute to pollutants other than sediment, along with construction-related waste.
Following the “golden rules” of construction stormwater management will put you on track to meet compliance standards and minimize stormwater pollution.
Reduce soil erosion. The easiest way to keep sediment out of waterways? Prevent the erosion in the first place. Contributions to an increase in erosion are:
- Removing vegetation
- Exposing sub-soil to weathering and vehicle traffic
- Reshaping the land
- Allowing gullies to form and grow
- Longer/steeper slopes
By minimizing these factors on your site, erosion both during and after construction will significantly decrease. Erosion prevention measures are a specific set of approved best management practices (BMPs) that are used during and after construction site preparation in order to safely convey clean water to storm drains or towards downstream waterways. Such measures include but are not limited to: phasing and construction sequencing, surface roughening, temporary seeding, mulching, erosion control blankets, and reinforcement matting.
Remove the sediment. Sediment control BMPs are used to reduce and/or eliminate the amount of sediment and other pollutants that are found in surface water runoff. Sediment control measures, such as silt fences, are usually passive systems that rely on filtering or settling the particles out of the wind or water that is transporting them.
Manage construction material and equipment. Materials associated with construction activities must be delivered, used, and stored according to practices that prevent these materials from polluting receiving waters. Typical materials include PCC components, petroleum products, pesticides, herbicides, fertilizers, detergents, plasters, acids, lime, glues, adhesives, paints, and solvents. Solid construction wastes must be collected, stored, and disposed of using practices that minimize contact with storm water. Solid wastes include such items as used brick, mortar, timber, steel, vegetation/landscaping waste, empty material containers, and litter.
Inspect and maintain. Routine inspections are an integral part of regularly performed maintenance activities–cleaning, repair, and replacement–necessary to ensure the integrity and effectiveness of BMPs. Construction site activities can damage BMPs, and routine inspection and maintenance minimizes the work required to prepare a site before a rain event, and it helps protect a site from unforeseen rains. Inspections should also occur before and after rain events.
Amanda Czepiel, J.D., is a Legal Editor for BLR’s environmental law publications. Ms. Czepiel has over 6 years of experience as an attorney and writer in the field of environmental compliance resources and has published numerous articles on a variety of environmental law topics, including wastewater and NPDES permitting, brownfields and contaminated sites remediation, oil spill prevention, wetlands, and corporate sustainability. Before starting her career in publishing, Ms. Czepiel worked in hospitality consulting and for various non-profit organizations and government agencies in the environmental field. Ms. Czepiel received her law degree from the University of Connecticut School of Law.