FLASHBACK TO 2011: United States EPA's proposed "Stormwater Rule" explained at StormCon session



Note to Reader:

The United States Environmental Protection Agency (EPA) is required under a 2010  settlement with the Chesapeake Bay Foundation to propose a new rule to  strengthen the stormwater program. The original deadline was September 2011,  and there have been several extensions. 


Capture Rain Where It Falls

“EPA’s long-anticipated stormwater rule is close to being released. At StormCon 2011 in Anaheim, CA, in late August, Jeremy Bauer, an environmental scientist with EPA’s Office of Wastewater Management, gave a presentation outlining the rule,” wrote Janice Kaspersen, editor of Stormwater Magazine, in her blog on October 1, 2011.

According to Jeremy Bauer, “Key elements of the rule’s approach include integrating green infrastructure into project design, viewing stormwater as a resource, and generally slowing the flow of runoff to allow more infiltration, which will not only reduce the volume of runoff but also the amount of pollutants reaching receiving waters.”

“In response to a question from the audience about calculating the amount of runoff retained, Bauer said that EPA is assuming designing for a ‘dry antecedent’—that is, a single storm, rather than conditions in which ponds are partially full or soils partially saturated from a previous storm.”


Elements of the New Stormwater Rule

The “Stormwater Rule” will quantify performance standards for new development and redeveloped sites, based on a specific storm (the 95th percentile storm, for example). Recognizing that there may be site constraints on redevelopment site, and also that redevelopment has environmental benefits compared to developing greenfield sites, the rule will hold redevelopment sites to a lesser standard (a lower percentile storm). Credits may be available for incorporating smart growth principles.

It will require MS4s (i.e. Municipal Separate Storm Sewer Systems) to develop plans to address discharge from existing sites—in other words, retrofits. This requirement applies to municipal, not private, property.

It will extend the protection of the MS4 program, possibly to include areas not now included such as arterial roads connecting urbanized areas.


Municipal Separate Storm Sewer Systems (MS4)

“The US currently has about 6,700 municipal separate storm sewer systems (MS4s), Bauer noted, and these cover about 2% of the country’s land area. Although that area contains a large portion of the population, considerable development falls outside it, such as new development on the margins of MS4s and the thoroughfares connecting them, and some of these areas will be considered for coverage,” reported Janice Kasperson.


To Learn More:

To download and read the complete article by Janice Kaspersen, click on The New Stormwater Rule