Fall is here and winter is right around the corner, bringing with it rain and snow.  In large volumes, the rain or snowmelt can create stormwater runoff if it doesn't seep into the ground. Stormwater management is an issue that developers need to think about when planning out their sites, not only to protect their property against damage, but also to ensure compliance with the regulations imposed by state and local agencies.  Lack or improper development of stormwater measures could affect the integrity of building structures and surrounding areas.

Complying With Stormwater Regulations

There are various ways to mitigate stormwater issues, which I recently discussed as part of a webinar produced and aired by the Strafford, an industry provider of professional Continuing Legal/Education credits. The webinar (titled “Stormwater Discharge and CWA Compliance After EPA Rule Revisions and Recent High Profile Spills”) provided clarification on the recently revised stormwater discharge permit requirements. A number of recent projects I worked on brought to light key issues and concerns for complying with these stormwater discharge permitting requirements.  I was able to share some best management practices and give an overview of the current trends as they relate to state mandated stormwater discharge permits  (For more about that see here. Strafford has also made the actual recording of the webinar available via their website)

Stormwater – When Rain and Snow Becomes an Issue
Stormwater occurs naturally, from rain or melting snow, which runs off streets, lawns, and other sites. When stormwater is absorbed into the ground, it is naturally filtered and allowed to replenish the soil or flow into bodies of water, such as streams and rivers. But when land is developed with impervious surfaces, such as pavement, it prevents precipitation from soaking back into the ground. As a result, the water can rapidly drain into storm drains, sewer systems, drainage ditches and other areas that are not equipped for this volume of run-off.  This causes a variety of problems including stream flooding and bank erosion; habitat destruction; infrastructure damages; and contaminated streams, rivers, and coastal water.

Following Best Management Practices (BMP) Manual guidelines

Traditionally, stormwater management design has consisted of the collection of stormwater through piped networks and transporting it to an offsite location - either directly to a stream, river or a water basin, or into a combined sewer system that goes into a wastewater treatment plant. Other methods of stormwater management include Low impact development (LID) and wet weather green infrastructure.

The Environmental Protection Agency has published a menu of stormwater Best Management Practices (BMP) for controlling storm runoff.  The manual gives engineers the opportunity to incorporate a variety of stormwater management devices into their site designs. Many States have developed their own regulations based on this manual, which stipulate the measures that builders and property owners must implement to manage stormwater issues.  The New Jersey Stormwater Best Management Practices Manual for example states that if the design of any development disturbs at least one acre of land or increases impervious surfaces by at least ¼ of an acre the engineer must incorporate structural and/or non-structural stormwater management measures that prevent the loss of groundwater recharge at the site.

Stormwater Management In Urban Areas

In urban areas it is more difficult to manage stormwater, due in part to the lack of land available to create large basins or large structural drainage systems. Non-structural systems are a much more feasible way to mitigate stormwater issues. Some of these non-structural measures can include the installation of porous pavement, rain gardens, downspout planters, green roofs, or underground systems (or 'grey stormwater systems').  The benefit of adding features such as natural plants, decorative porous pavement, and green roofs is two-fold: in addition to addressing the stormwater problem and managing a potential threat to infrastructure and environment, these features improve properties values by adding pleasing aesthetic elements. The Best Management Practice Manual on your State's DEP will provide further detail on requirements and recommended measures.