What's a Wetland, Anyhow?

Science  25 Aug 2006:
Vol. 313, Issue 5790, pp. 1019
DOI: 10.1126/science.1132934

Brooks Hanson Anyone interested in water and environmental science should study the U.S. Supreme Court's opinion—or, more precisely, its three rather different opinions—in the recent case called Rapanos vs. United States. Don't tune out if you're in Asia, Europe, or elsewhere, because this is NOT merely a domestic issue! Water quality is critical internationally, improvements in water quality have been a major source of global public health benefits (see the special section, p. 1067), and U.S. regulatory approaches are sometimes copied elsewhere.

Here's what the Court was facing. The Clean Water Act mandates that the U.S. Army Corps of Engineers issue regulations defining what fits under the act's umbrella term “waters of the United States.” The Court of Appeals for the Sixth Circuit had upheld federal jurisdiction over Michigan wetlands in Rapanos, finding that there were hydrologic connections between the site and nearby ditches and drains, and thence to navigable waters. Defendants appealed to the Supreme Court, which issued its opinions on 19 June 2006.

The Court's fundamental split will surprise few. Justice Scalia, representing the views of Roberts, Alito, Thomas, and himself, offered a very restrictive definition of wetlands: They must have surface connections to navigable waters. That view would have stripped regulatory protection from lands historically treated as wetlands by the Corps of Engineers. On the other side, Justice Stevens, for Souter, Ginsberg, and Breyer, favored a definition that includes groundwater with a significant nexus of connection to more distant navigable waters. Justice Kennedy wrote the decisive opinion, in effect bouncing the matter back to the appellate court. His position favored the “significant nexus” view, adding that the determination would essentially be a scientific matter, within the proper scope of the regulatory agency's authority. That leaves the matter approximately where it was, but the tone of the opinions is revealing with respect to the depth and tenor of the disagreement on the Court.


There are jabs and needles everywhere. Stevens said that Scalia's opinion “disregards its own obligation to interpret laws rather than make them.” The Chief Justice's separate opinion criticized the Corps for failing to issue regulatory revisions after an earlier Court decision, saying that it had an “essentially boundless view of the scope of its power.” Scalia, in what reads like a dissenting opinion, said that the Stevens definition of wetlands was “beyond parody.” Ouch.

This case also signals how different justices might apply science as a guide to decision-making. “Beyond parody” might also fit Scalia's effort to define terms used in hydrology. His search for commonplace labels as proxies for scientific definitions must have left his copy of Webster's Dictionary dog-eared from overuse; the text cites it over and over again. His opinion shows no awareness of what hydrologic investigations have demonstrated about the interconnectedness of ground and surface waters. Neither is there any suggestion that groundwater moves (it does) or that it regularly feeds surface streams or lakes, often keeping these waters flowing between rainstorms. The essential message is: “If you can't see it, it doesn't matter.”

There is a missing precedent here. An earlier Supreme Court case, Borden Ranch and Tsakopoulos vs. U.S. Army Corps of Engineers and U.S. Environmental Protection Agency, ended in a 4-4 tie, thereby letting stand a decision that fined Tsakopoulos for a plowing technique that the government said would damage the underlying wetland. Ironically, Kennedy had recused himself because he knew Tsakopoulos. Given his views in Rapanos, he would likely have sided with the government, creating a precedent that might have moved the Court not to hear Rapanos.

Two take-home lessons seem clear. First, Kennedy is knowledgeable about environmental science; Scalia has little knowledge or perhaps only little interest. Second, despite the meager opportunity for direct scientific input to the Court, concerned scientists could help federal agencies work out realistic scientific standards for defining a “significant nexus” and get those into the Code of Federal Regulations. They might also be useful in the next big case, when the Court will decide whether carbon dioxide is a pollutant under the Clean Air Act. Perhaps they could give the justices something more scientifically helpful than Webster.

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