As you could probably tell from the number of posts I’ve written on the subject, stormwater fascinates me. Not that I particularly like rain or snow (particularly after this winter!). But, as an environmental concern and legal and policy issue, there are few subjects that can match both its simplicity – we all know what stormwater is – and its complexity – figuring out how to effectively control it has proven to be one of the more intransigent problems confronting EPA and the states. In fact, one of the very first cases I worked on over 25 years ago involved stormwater, and, despite some progress, the legal and policy debates over stormwater continue today. Given my interest in the topic, my next few posts are going to focus on stormwater.
What is it about stormwater? To begin, it’s well-established that stormwater discharges – both point and non-point – are significant contributors to surface water quality impairment. Major water bodies, such as the Chesapeake Bay and the Mississippi River, are not achieving water quality standards to a significant extent because of the contribution of stormwater containing nutrients and other pollutants. That stormwater presents an environmental problem that still needs to be addressed is difficult to dispute.
Easy enough, but figuring how to deal with stormwater remains a thorny issue. Part of the difficulty arises from the Clean Water Act itself - the way in which it divides responsibilities between the federal and state governments; how it defines which stormwater discharges are to be controlled and which are exempt; and how the non-stormwater provisions of the Act interact with the Act’s stormwater mandates. These tensions are what I intend to explore over several posts. I’ll start in this post by describing the general framework of the Clean Water Act’s regulation of stormwater.
The Clean Water Act divides sources of pollution into two general categories: (1) point and (2) non-point. Point sources are discernible, confined and discrete conveyances, such as pipes, ditches, tunnels, and conduits of any type. Non-point sources are everything else – think sheet flow that enters a water body but not through a pipe, ditch or culvert. And, as I previously explained, the Act exempts some discharges which would otherwise appear to qualify as “point source” discharges, such as irrigation flow returns and stormwater from certain agricultural or silvicultural activities. In essence, such discharges are considered “non-point” discharges. Stormwater, of course, enters water through both point and non-point sources.
The Act then divides responsibility for point and non-point sources between U.S. EPA and the states. EPA is authorized to issue general rules for point source discharges, including stormwater discharges from point sources, and establish a nationwide permit program for such discharges. States can submit a request to EPA to assume responsibility for that point source discharge permit program assuming their program meets the minimum qualifications established by EPA. In general terms, however, point source discharges are a federal responsibility which can be shared with the states who typically take over their permitting.
That’s not the case for non-point sources. EPA is prohibited from establishing requirements for non-point sources; only states may take direct action to address these sources. The rationale is that the most effective way to regulate sheet flow/non-point sources - such as runoff from urban and suburban development – is to regulate land use. Land use regulation has historically been, and continues to be, an issue of state and local concern. Congress did not want EPA, through the Clean Water Act, to become involved in or be responsible for such local land use decisions.
While there are sound reasons for the Act’s division of responsibility between the federal and state governments, there’s no question that it restrains EPA’s authority over stormwater. Because EPA cannot regulate non-point sources/sheet flow, it can’t directly address a significant portion of the problem. This doesn’t mean non-point sources go unregulated, only that it is more difficult to control them. Total Maximum Daily Loads (TMDLs) are the most obvious approach. If a water body is impaired (i.e., does not meet water quality standards), a state must establish a TMDL, in which the state specifies the maximum allowable loads from both point and non-point sources to ensure attainment of water quality standards.
The Clean Water Act contains special provisions for permitting of point source stormwater discharges. The Act requires stormwater permits for (1) industrial activities, (2) medium and large municipal separate sewer systems, and, of particular interest of late (3) sources which EPA or a state determines contribute to violations of water quality standards or which are significant contributors of pollutants (the so-called “residual authority”).
In my next few posts, I intend to review some of the more interesting current stormwater issues, including attempts by NGOs to have EPA exercise its residual authority to control stormwater, EPA’s revised effluent guidelines for the construction industry, and others. Stay tuned.