In the interest of helping to avoid misunderstandings about DDOE’s proposed rulemaking on stormwater management and soil erosion and sediment control, DDOE documents below some of the misconceptions that it has encountered, along with DDOE’s attempt to briefly clarify the rule’s provisions.
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Misconception: Regulated sites must prove that they can’t achieve retention on site before being allowed to achieve retention off site.
DDOE Clarification: After achieving on-site retention for a minimum of 50% of the required Stormwater Retention Volume (SWRv), a regulated site is free to use off-site retention for the remaining volume, without first having to show or prove anything about on-site retention capacity. However, a regulated site cannot retain less than 50% of the SWRv on site, unless the applicant proves that it is technically infeasible or environmentally harmful to retain that volume on site.
Misconception: Most development sites are not a big part of the stormwater pollution problem. It is sites like gas stations that handle gas, oil, and other potential pollutants that are causing stormwater pollution.
DDOE Clarification: Though stormwater pollution is partially a problem of individuals intentionally or carelessly dumping oil or other products down storm drains or on the ground to wash into storm drains, it is largely an unintentional consequence of rainwater falling on rooftops, parking lots, and other impervious surfaces. Stormwater runs off these surfaces, not only carrying the pollutants in its path, but also accumulating with powerful erosive force that gouges out streambanks and degrades water quality and aquatic habitat. Though sites like gas stations have impervious surface and contribute to this, they are only a small part of the total impervious area, and the District’s existing stormwater management regulations have requirements for installing technologies to remove oil and grease from stormwater flowing into Best Management Practices installed on sites like these (21 DCMR § 529.2).
Just as people are not intentionally setting out to pollute the air when they turn on their cars, developers and property owners are not intentionally setting out to pollute waterbodies every time it rains. Nonetheless, this pollution is a problem that we must address, and the District’s proposed rulemaking will help the District to gradually reduce the harmful impact on the District’s waterbodies. Just as new federal standards for automobile emissions or fuel efficiency apply to newly manufactured cars rather than immediately impacting the owners of existing cars, these stormwater management requirements do not immediately impact all developed areas in the District. Instead, they are triggered only when a developer undertakes a large construction project. This is consistent with how stormwater has been regulated by the District for more than two decades and with how it is regulated by other jurisdictions. It is also consistent with other types of regulations, including for automobiles, mentioned above, and other sources of air pollution. For example, under the Clean Air Act, any new construction of, or modification to, a major source of air pollution requires emission control upgrades at the time of development/installation.