Waiting for the Stormwater Rule

As most of us are aware, EPA is working on a new stormwater rule–and has been for well over a year. At StormCon in August, Jeremy Bauer of EPA’s Office of Wastewater Management provided an overview of the upcoming rule, answered audience questions, and noted comments to take back to EPA.

As EPA has long stated–and as Bauer outlined when he spoke at last year’s conference–the new rule will emphasize using green infrastructure and infiltrating stormwater when possible. This is a shift from the old practice of moving runoff offsite to detention ponds or water bodies and attempting to manage peak flows. The emphasis on green infrastructure is not new; EPA has been moving in this direction for some time. The idea, he noted, is to view stormwater as a resource, and to realize that reducing the volume of runoff from a site also reduces the amount of pollutants that ultimately reach water bodies.

Bauer also outlined the four key elements we should expect in the proposed rule:

1. It will establish performance standards for discharges from newly developed and redeveloped sites.
2. Some regulated MS4s will also need to address discharges from existing sites through retrofits.
3. The protection of the MS4 program will be extended.
4. Government-owned maintenance yards will now be designated as industrial sources.

The third point here is an interesting one; it means that in addition to the traditionally defined MS4 regions–for Phase II, this has generally been urbanized areas with populations of 50,000 or more–the new rule will consider additional areas such as the margins of these MS4 regions.

Bauer provided some interesting statistics that help explain why EPA is looking at these “fringe” areas. Currently in the US, 100 million acres are developed; about 25% of that developed area has impervious cover. Another 800,000 acres are being developed every year–much of it on the fringes of existing cities–and by 2040 the annual amount is expected to be about 1.2 million acres. Discharge from impervious cover is about 16 times that of discharge from undeveloped land, and we start to see biological impacts to surface waters when the impervious cover in a watershed is only 1 or 2%. By the time more than 15% of a watershed is impervious, severe degradation of surface waters is usually occurring.

Other points of note: The rule will take existing state programs into account and will allow them to continue if they’re essentially achieving the same result. Site constraints will also be considered, and those that can’t retain the required volume of runoff onsite will have other options, such as offsite mitigation within the same watershed or payment in lieu of retention.

The proposed rule is now scheduled for release June 2013, with the final rule expected by December 2014.

We probably all have opinions as to what we’d like to see in the new rule–the guest editorial on page 8 of this issue offers some detailed and thoughtful suggestions on the topic–and we will all get a chance to respond during the public comment period once the rule is released but before it’s finalized. In the meantime, if you’d like to share your thoughts on what you hope the rule contains, leave a comment below.