A 2006 Supreme Court decision has seriously hindered EPA's ability to enforce the Clean Water Act, according to new documents released by two House Committee chairmen.

The decision in the case, which pertained to enforcement of the act in non-navigable wetlands, made a real mess of things. According to The Washington Post, "That 5 to 4 decision, known as Rapanos v. United States, held that the Army Corps of Engineers had exceeded its authority when it denied two Michigan developers permits to build on wetlands…"

But the majority opinion was split. While four of the five wanted to kneecap the Corps' ability to preserve wetlands from development, the other, Justice Kennedy, wrote a separate opinion to advocate for case-by-case evaluation.

Even though the Rapanos case related to an Army Corps of Engineers permitting decision, it had big implications for the Clean Water Act at large and EPA's enforcement of it. That led the Corps and EPA to issue a joint guidance document that attempts to clarify federal enforcement obligations in the wake of the decision.

But apparently, the guidance isn't working. In a memo released by Reps. Henry Waxman (D-CA) and James Oberstar (D-MN), EPA admits that the uncertainty created by the Rapanos decision has forced staff to abandon or alter enforcement actions against wetland polluters. From the memo:

Data collected from the regions shows that a significant portion of the CWA enforcement docket has been adversely affected. While we are not able to distinguish whether these impacts are due primarily to the Rapanos decision or to the Guidance, this information revealed that from July 2006 to the present, [EPA regional offices] decided not to pursue formal enforcement in 304 separate instances where there were potential CWA violations because of jurisdictional uncertainty. In addition, the regions identified 147 instances where the priority of an enforcement case was lowered due to jurisdictional concerns. Finally, the regions indicated that lack of CWA jurisdiction has been asserted as an affirmative defense in 61 enforcement cases since July 2006. Thus, since July 2006, the Rapanos decision or the Guidance negatively affected approximately 500 enforcement cases.

Waxman and Oberstar wrote a critical letter to EPA Administrator Stephen Johnson because "instead of sounding the alarm about the EPA's enforcement problems, the agency's public statements have minimized the impact of the Rapanos decision."