From Jeffrey Collier of GT West Palm Beach:

On May 2, 2011, the U.S. Environmental Protection Agency and the U.S. Army Corps of Engineers published proposed joint guidance ("Proposed Guidance") describing how the agencies will identify waters regulated pursuant to Section 404 of the Clean Water Act ("CWA").  The Proposed Guidance is intended to clarify and implement the Supreme Court’s decisions in Solid Waste Agency of Northern Cook County v. U.S. Army Corps of Engineers ("SWANCC"), 531 U.S. 159 (2001), and Rapanos v. United States, 547 U.S. 715 (2006).  The Proposed Guidance asserts that it is further intended to reaffirm federal jurisdiction over waters that currently lack clear protection under the law, and to provide clearer, more predictable guidelines to reduce uncertainty and delay for businesses and regulators. 

The Proposed Guidance allows the EPA and the Corps to expand the universe of waters covered under Justice Kennedy’s Rapanos "significant nexus" text by allowing the use of a "watershed analysis" to aggregate similarly situated waters and wetlands within a watershed without requiring the kind of detailed site-specific analysis for individual adjacent wetlands required under the current Guidance.  The agencies acknowledge that the number of water bodies found subject to CWA jurisdiction will increase greatly under the new guidance.  The costs of such expansion of jurisdiction will be felt by the regulated community.

The comment period for the Proposed Guidance has been extended from July 1, 2011 to July 31, 2011.  The Proposed Guidance would supersede existing guidance documents including the 2008 Bush Administration Guidance (the 2008 Guidance will remain in effect until the Proposed Guidance is issued).  After the Proposed Guidance is issued, the agencies will likely conduct a formal rulemaking process to further clarify the extent of the CWA jurisdiction.