The Supreme Court declined to hear a challenge to the EPA’s Chesapeake Bay cleanup plan, letting stand a Third Circuit ruling that the program did not violate the Clean Water Act. In order to address stubborn, persistent agricultural pollution in one of the nation’s largest estuaries, the EPA instituted a complex scheme to regulate key pollutants being discharged into the Bay.

Agricultural interests and developers sued, arguing that the cleanup plan went beyond what the Clean Water Act allowed and usurped the powers of the states. Had their arguments been successful, the EPA could have seen its efforts to address stubborn water pollution hampered in a major way.

TMDL = Too Much Dang (Po)lluttion!

The Chesapeake Bay is the largest estuary in the lower 48, with more than 150 rivers from six states draining into its 64,229 square mile basin. In addition to water, from New York, Pennsylvania, Delaware, Maryland, Virginia, and West Virginia, those rivers bring tons of agricultural and other runoff, which reaches the Bay, deteriorating the Bay environment and fish and seafood populations.

Under the Clean Water Act, the EPA’s main tool for fighting water pollution is pollution discharge permits. But, when a waterbody is contaminated by “nonpoint source” pollution like runoff, the CWA allows the EPA to create a “total daily maximum load” for that waterbody. In a TMDL, the Agency sets maximum amounts of specified pollutants a waterbody can receive and allocates the needed reductions among pollution sources.

The World’s Largest TMDL

And that is just what the EPA did with the Chesapeake. In 2010, the Agency issued the Bay TMDL, focused on common the agricultural runoff pollutants nitrogen and phosphorous, as well as sediment. The largest TMDL ever implemented, it was no simple plan. The process established by the TMDL included air pollution reductions, trading and offset systems, and extensive monitoring. And that’s on top of 92 smaller TMDLs for individual segments of the Bay.

When agricultural and development interests sued, they argued that “total daily maximum load” in the Clean Water Act was unambiguous: the EPA could only set a total maximum amount of pollutants dischargeable into a waterbody and nothing more. The Agency could not allocate permissible levels, set target dates, or require assurances.

It was a novel argument and one solidly rejected by the Third Circuit. Under Chevron, the Act’s TMDL language was ambiguous to allow the EPA to determine not just a total number of pollutants but ITAL how ITAL to achieve that goal.

TMDLs Live to Fight Another Day

Were the Supreme Court to accept the petitioner’s appeal, it could have had serious implications for the EPA, the Clean Water Act, and water pollution generally. The Clean Water Act is weakest when it comes to dealing with nonpoint source pollution. Environmentalists have long called on the Agency to make better use of TMDLs to deal with pollution that cannot be pinned to a single pipe or discharger.

With the Bay TMDL, the EPA has finally started to do so. Had the Court taken up the case, all of those efforts could have been put into question, if not halted. For now, however, the Bay TMDL remains intact.

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