[Originally published in The Wendel Report, Spring 2010 issue.]
California's long-awaited issuance of the new Construction General Storm Water Permit last fall was big news, but there's more to come. US EPA is gathering information in preparation for drafting new and expanded storm water regulations. By all indications, the new regulations will address site development and design, thus directly impacting architects, builders and developers.
Many of the nation's surface waters remain impaired by urban runoff because impervious surfaces cause larger flows that erode channels and transport sediment and urban pollutants to surface waters. To keep the problem from getting worse, EPA is looking to impose stringent requirements on new development and redevelopment projects to implement measures to maintain post-construction flows at pre- construction levels. Common strategies to maintain the post- construction "water balance" include infiltration and capture and reuse of storm runoff. These strategies are also being pursued in California to ease increasingly severe water supply shortages. In the last several years, California has required larger municipalities to impose similar restrictions on new development and redevelopment projects, and the new Construction Permit now extends those requirements to smaller communities. Many have found that designing sites to meet these requirements can be challenging and costly, especially when clay soils or limited space make pervious surfaces and onsite storage options impractical. In some urban settings, the space requirements of such features may even be misaligned with another environmental effort: increasing public transit use to reduce green house gas emissions by increasing urban density. The new rules may go so far as to shift the basis of storm water permit requirements to impervious surface areas or storm water flows rather than simply site use.
To address problems caused by existing infrastructure, staff are also considering retrofitting requirements. As much of the country's aging infrastructure will have to be replaced in upcoming years, EPA sees an opportunity to refocus conveyance system design on water quality protection as well as flood control.
It is too early to know how EPA's approach will compare with or change California's program. California's experience may serve as a model for EPA, or merely a starting point. And some are worried that applying a single national standard to the wide variety of climates, soils and geography may compound the already difficult challenges of storm water management.
EPA held listening sessions in five major cities during January, and solicited public comments to inform its rule making. EPA has targeted September 2011 for the release of its draft rule. At that time, the public will have an opportunity to comment on the specifics of the agency's proposal. EPA hopes to adopt final regulations in 2012.